Biological activity and photostability of biflorin micellar nanostructures.

Science.gov (United States)

Santana, Edson R B; Ferreira-Neto, João P; Yara, Ricardo; Sena, Kêsia X F R; Fontes, Adriana; Lima, Cláudia S A

2015-05-13

Capraria biflora L. is a shrub from the Scrophulariaceae family which produces in its roots a compound named biflorin, an o-naphthoquinone that shows activity against Gram-positive bacteria and fungi and also presents antitumor and antimetastatic activities. However, biflorin is hydrophobic and photosensitive. These properties make its application difficult. In this work we prepared biflorin micellar nanostructures looking for a more effective vehiculation and better preservation of the biological activity. Biflorin was obtained, purified and characterized by UV-Vis, infrared (IR) and 1H- and 13C-NMR. Micellar nanostructures of biflorin were then assembled with Tween 80®, Tween 20® and saline (0.9%) and characterized by UV-Vis spectroscopy and dynamic light scattering (DLS). The results showed that the micellar nanostructures were stable and presented an average size of 8.3 nm. Biflorin micellar nanostructures' photodegradation was evaluated in comparison with biflorin in ethanol. Results showed that the biflorin in micellar nanostructures was better protected from light than biflorin dissolved in ethanol, and also indicated that biflorin in micelles were efficient against Gram-positive bacteria and yeast species. In conclusion, the results showed that the micellar nanostructures could ensure the maintenance of the biological activity of biflorin, conferring photoprotection. Moreover, biflorin vehiculation in aqueous media was improved, favoring its applicability in biological systems.

Biological Activity and Photostability of Biflorin Micellar Nanostructures

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Edson R. B. Santana

2015-05-01

Full Text Available Capraria biflora L. is a shrub from the Scrophulariaceae family which produces in its roots a compound named biflorin, an o-naphthoquinone that shows activity against Gram-positive bacteria and fungi and also presents antitumor and antimetastatic activities. However, biflorin is hydrophobic and photosensitive. These properties make its application difficult. In this work we prepared biflorin micellar nanostructures looking for a more effective vehiculation and better preservation of the biological activity. Biflorin was obtained, purified and characterized by UV-Vis, infrared (IR and 1H- and 13C-NMR. Micellar nanostructures of biflorin were then assembled with Tween 80®, Tween 20® and saline (0.9% and characterized by UV-Vis spectroscopy and dynamic light scattering (DLS. The results showed that the micellar nanostructures were stable and presented an average size of 8.3 nm. Biflorin micellar nanostructures’ photodegradation was evaluated in comparison with biflorin in ethanol. Results showed that the biflorin in micellar nanostructures was better protected from light than biflorin dissolved in ethanol, and also indicated that biflorin in micelles were efficient against Gram-positive bacteria and yeast species. In conclusion, the results showed that the micellar nanostructures could ensure the maintenance of the biological activity of biflorin, conferring photoprotection. Moreover, biflorin vehiculation in aqueous media was improved, favoring its applicability in biological systems.

Micellar polymerization: Computer simulations by dissipative particle dynamics.

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Shupanov, Ruslan; Chertovich, Alexander; Kos, Pavel

2018-07-15

Nowadays, micellar polymerization is widely used in different fields of industry and research, including modern living polymerization technique. However, this process has many variables and there is no comprehensive model to describe all features. This research presents simulation methodology which describes key properties of such reactions to take a guide through a variety of their modifications. Dissipative particle dynamics is used in addition to Monte Carlo scheme to simulate initiation, propagation, and termination events. Influence of initiation probability and different termination processes on final conversion and molecular-weight distribution are presented. We demonstrate that prolonged initiation leads to increasing in polymer average molecular weight, and surface termination events play major role in conversion limitation, in comparison with recombination. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

Two-phase aqueous micellar systems: an alternative method for protein purification

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Rangel-Yagui C. O.

2004-01-01

Full Text Available Two-phase aqueous micellar systems can be exploited in separation science for the extraction/purification of desired biomolecules. This article reviews recent experimental and theoretical work by Blankschtein and co-workers on the use of two-phase aqueous micellar systems for the separation of hydrophilic proteins. The experimental partitioning behavior of the enzyme glucose-6-phosphate dehydrogenase (G6PD in two-phase aqueous micellar systems is also reviewed and new results are presented. Specifically, we discuss very recent work on the purification of G6PD using: i a two-phase aqueous micellar system composed of the nonionic surfactant n-decyl tetra(ethylene oxide (C10E4, and (ii a two-phase aqueous mixed micellar system composed of C10E4 and the cationic surfactant decyltrimethylammonium bromide (C10TAB. Our results indicate that the two-phase aqueous mixed (C10E4/C10TAB micellar system can improve significantly the partitioning behavior of G6PD relative to that observed in the two-phase aqueous C10E4 micellar system.

Micellar Self-Assembly of Recombinant Resilin-/Elastin-Like Block Copolypeptides.

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Weitzhandler, Isaac; Dzuricky, Michael; Hoffmann, Ingo; Garcia Quiroz, Felipe; Gradzielski, Michael; Chilkoti, Ashutosh

2017-08-14

Reported here is the synthesis of perfectly sequence defined, monodisperse diblock copolypeptides of hydrophilic elastin-like and hydrophobic resilin-like polypeptide blocks and characterization of their self-assembly as a function of structural parameters by light scattering, cryo-TEM, and small-angle neutron scattering. A subset of these diblock copolypeptides exhibit lower critical solution temperature and upper critical solution temperature phase behavior and self-assemble into spherical or cylindrical micelles. Their morphologies are dictated by their chain length, degree of hydrophilicity, and hydrophilic weight fraction of the ELP block. We find that (1) independent of the length of the corona-forming ELP block there is a minimum threshold in the length of the RLP block below which self-assembly does not occur, but that once that threshold is crossed, (2) the RLP block length is a unique molecular parameter to independently tune self-assembly and (3) increasing the hydrophobicity of the corona-forming ELP drives a transition from spherical to cylindrical morphology. Unlike the self-assembly of purely ELP-based block copolymers, the self-assembly of RLP-ELPs can be understood by simple principles of polymer physics relating hydrophilic weight fraction and polymer-polymer and polymer-solvent interactions to micellar morphology, which is important as it provides a route for the de novo design of desired nanoscale morphologies from first principles.

Profluorescent PPV-Based Micellar System as a Versatile Probe for Bioimaging and Drug Delivery.

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Zaquen, Neomy; Lu, Hongxu; Chang, Teddy; Mamdooh, Russel; Lutsen, Laurence; Vanderzande, Dirk; Stenzel, Martina; Junkers, Thomas

2016-12-12

Although micelles are commonly used for drug delivery purposes, their long-term fate is often unknown due to photobleaching of the fluorescent labels or the use of toxic materials. Here, we present a metal-free, nontoxic, nonbleaching, fluorescent micelle that can address these shortcomings. A simple, yet versatile, profluorescent micellar system, built from amphiphilic poly(p-phenylenevinylene) (PPV) block copolymers, for use in drug delivery applications is introduced. Polymer micelles made from PPV show excellent stability for up to 1 year and are successfully loaded with anticancer drugs (curcumin or doxorubicin) without requiring introduction of physical or chemical cross-links. The micelles are taken up efficiently by the cells, which triggers disassembly, releasing the encapsulated material. Disassembly of the micelles and drug release is conveniently monitored as fluorescence of the single polymer chains appear, which enables not only to monitor the release of the payload, but in principle also the fate of the polymer over longer periods of time.

Modulating Pluronics micellar rupture with cyclodextrins and drugs: effect of pH and temperature

International Nuclear Information System (INIS)

Valero, M; Dreiss, C A

2014-01-01

Micelles of the triblock copolymer Pluronic F127 can encapsulate drugs with various chemical structures and their architecture has been studied by small-angle neutron scattering (SANS). Interaction with a derivative of β-cyclodextrin, namely, heptakis(2,6-di-O- methyl)-β-cyclodextrin (DIMEB), induces a complete break-up of the micelles, providing a mechanism for drug release. In the presence of drugs partitioned within the micelles, competitive interactions between polymer, drug and cyclodextrin lead to a modulation of the micellar rupture, depending on the nature of the drug and the exact composition of the ternary system. These interactions can be further adjusted by temperature and pH. While the most widely accepted mechanism for the interaction between Pluronics and cyclodextrins is through polypseudorotaxane (PR) formation, involving the threading of β-CD on the polymer backbone, time-resolved SANS experiments show that de-micellisation takes place in less than 100 ms, thus unambiguously ruling out an inclusion complex between the cyclodextrin and the polymer chains

The fabrication of highly ordered block copolymer micellar arrays: control of the separation distances of silicon oxide dots

Science.gov (United States)

Yoo, Hana; Park, Soojin

2010-06-01

We demonstrate the fabrication of highly ordered silicon oxide dotted arrays prepared from polydimethylsiloxane (PDMS) filled nanoporous block copolymer (BCP) films and the preparation of nanoporous, flexible Teflon or polyimide films. Polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) films were annealed in toluene vapor to enhance the lateral order of micellar arrays and were subsequently immersed in alcohol to produce nano-sized pores, which can be used as templates for filling a thin layer of PDMS. When a thin layer of PDMS was spin-coated onto nanoporous BCP films and thermally annealed at a certain temperature, the PDMS was drawn into the pores by capillary action. PDMS filled BCP templates were exposed to oxygen plasma environments in order to fabricate silicon oxide dotted arrays. By addition of PS homopolymer to PS-b-P2VP copolymer, the separation distances of micellar arrays were tuned. As-prepared silicon oxide dotted arrays were used as a hard master for fabricating nanoporous Teflon or polyimide films by spin-coating polymer precursor solutions onto silicon patterns and peeling off. This simple process enables us to fabricate highly ordered nanoporous BCP templates, silicon oxide dots, and flexible nanoporous polymer patterns with feature size of sub-20 nm over 5 cm × 5 cm.

The fabrication of highly ordered block copolymer micellar arrays: control of the separation distances of silicon oxide dots

Energy Technology Data Exchange (ETDEWEB)

Yoo, Hana; Park, Soojin, E-mail: spark@unist.ac.kr [Interdisciplinary School of Green Energy, Ulsan National Institute of Science and Technology, Banyeon-ri 100, Ulsan 689-798 (Korea, Republic of)

2010-06-18

We demonstrate the fabrication of highly ordered silicon oxide dotted arrays prepared from polydimethylsiloxane (PDMS) filled nanoporous block copolymer (BCP) films and the preparation of nanoporous, flexible Teflon or polyimide films. Polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) films were annealed in toluene vapor to enhance the lateral order of micellar arrays and were subsequently immersed in alcohol to produce nano-sized pores, which can be used as templates for filling a thin layer of PDMS. When a thin layer of PDMS was spin-coated onto nanoporous BCP films and thermally annealed at a certain temperature, the PDMS was drawn into the pores by capillary action. PDMS filled BCP templates were exposed to oxygen plasma environments in order to fabricate silicon oxide dotted arrays. By addition of PS homopolymer to PS-b-P2VP copolymer, the separation distances of micellar arrays were tuned. As-prepared silicon oxide dotted arrays were used as a hard master for fabricating nanoporous Teflon or polyimide films by spin-coating polymer precursor solutions onto silicon patterns and peeling off. This simple process enables us to fabricate highly ordered nanoporous BCP templates, silicon oxide dots, and flexible nanoporous polymer patterns with feature size of sub-20 nm over 5 cm x 5 cm.

Principles of Micellar Electrokinetic Capillary Chromatography Applied in Pharmaceutical Analysis

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Árpád Gyéresi

2013-02-01

Full Text Available Since its introduction capillary electrophoresis has shown great potential in areas where electrophoretic techniques have rarely been used before, including here the analysis of pharmaceutical substances. The large majority of pharmaceutical substances are neutral from electrophoretic point of view, consequently separations by the classic capillary zone electrophoresis; where separation is based on the differences between the own electrophoretic mobilities of the analytes; are hard to achieve. Micellar electrokinetic capillary chromatography, a hybrid method that combines chromatographic and electrophoretic separation principles, extends the applicability of capillary electrophoretic methods to neutral analytes. In micellar electrokinetic capillary chromatography, surfactants are added to the buffer solution in concentration above their critical micellar concentrations, consequently micelles are formed; micelles that undergo electrophoretic migration like any other charged particle. The separation is based on the differential partitioning of an analyte between the two-phase system: the mobile aqueous phase and micellar pseudostationary phase. The present paper aims to summarize the basic aspects regarding separation principles and practical applications of micellar electrokinetic capillary chromatography, with particular attention to those relevant in pharmaceutical analysis.

Thinking Outside the 'Block': Alternative Polymer Compositions for Micellar Drug Delivery.

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Jones, Marie-Christine

2015-01-01

With a number of formulations currently in clinical trials, the interest in polymer micelles as drug carriers in unlikely to subside. Historically, linear diblock copolymers have been used as the building blocks for micelle preparation. Yet, recent advances in polymer chemistry have meant that a wider variety of polymer architectures and compositions have become available and been trialed for pharmaceutical applications. This mini-review aims to provide an overview of recent, exciting developments in triblock, graft and hyperbranched polymer chemistries that may change the way polymeric micelles drug formulations are prepared.

Octane-Assisted Reverse Micellar Dyeing of Cotton with Reactive Dyes

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Alan Yiu-lun Tang

2017-12-01

Full Text Available In this study, we investigated the computer colour matching (CCM of cotton fabrics dyed with reactive dye using the octane-assisted reverse micellar approach. The aim of this study is to evaluate the colour quality and compare the accuracy between CCM forecasting and simulated dyeing produced by conventional water-based dyeing and octane-assisted reverse micellar dyeing. First, the calibration of dyeing databases for both dyeing methods was established. Standard samples were dyed with known dye concentrations. Computer colour matching was conducted by using the colour difference formula of International Commission on Illumination (CIE L*a*b*. Experimental results revealed that the predicted concentrations were nearly the same as the expected known concentrations for both dyeing methods. This indicates that octane-assisted reverse micellar dyeing system can achieve colour matching as good as the conventional water-based dyeing system. In addition, when comparing the colour produced by the conventional water-based dyeing system and the octane-assisted reverse micellar dyeing system, the colour difference (ΔE is ≤1, which indicates that the reverse micellar dyeing system could be applied for industrial dyeing with CCM.

Pyrene absorption can be a convenient method for probing critical micellar concentration (cmc) and indexing micellar polarity.

Science.gov (United States)

Basu Ray, Gargi; Chakraborty, Indranil; Moulik, Satya P

2006-02-01

The critical micellar concentration (cmc) of both ionic and non-ionic surfactants can be conveniently determined from the measurements of UV absorption of pyrene in surfactant solution. The results on a number of surfactants have agreed with that realized from pyrene fluorescence measurements as well as that obtained following conductometric, tensiometric and calorimetric methods. The absorbance vs [surfactant] profiles for all the major UV spectral peaks of pyrene have been found to be sigmoidal in nature which were analyzed according to Sigmoidal-Boltzmann equation (SBE) to evaluate the cmcs of the studied surfactants. The difference between the initial and the final asymptotes (a(i) and a(f), respectively) of the sigmoidal profile, Delta a = (a(f)-a(i)) and the slope of the sigmoid, S(sig) have been observed to depend on the type of the surfactant. The Delta a has shown a linear correlation with the ratio of the fluorescence intensities of the first and the third vibronic peaks, I1/I3 of pyrene which is considered as a measure of the environmental polarity (herein micellar interior) of the probe (pyrene). Thus, Delta a values have the prospect for use as another index for the estimation of polarity of micellar interior.

Redox behavior and optical response of nanostructured poly(3,4-ethylenedioxythiophene) films grown in a camphorsulfonic acid based micellar solution

International Nuclear Information System (INIS)

Bhandari, Shweta; Deepa, M.; Singh, S.; Gupta, Govind; Kant, Rama

2008-01-01

Poly(3,4-ethylenedioxythiophene) (PEDOT) films have been electropolymerized from an aqueous micellar solution comprising camphorsulfonic acid (CSA), lithium trifluoromethanesulfonate (LiCF 3 SO 3 ) and EDOT. The inclusion of the dopants CS - and CF 3 SO 3 - in the polymer structure and an unusually high doping level of 0.54 have been ascertained by the X-ray photoelectron spectroscopy. Transmission electron microscopy and atomic force microscopy studies show that the micellar effect of CSA leads to a morphology wherein polymer particles link together to form elongated shapes and also endows the film with a surface roughness of 25-30 nm. These nanostructures permit a facile intercalation-deintercalation of anions in the film during redox cycling. Electrochemical impedance spectroscopy show that the charge transfer phenomenon at the PEDOT-electrolyte interface is dominant in the high frequency region and diffusion controlled ionic movement prevails in the low frequency regime. The use of these films as potential cathodes in electrochromic windows is rationalized not only on the basis of their high scalability and ease of processing but also due to their large coloration efficiency (123 cm 2 C -1 ) and transmission modulation (50%) at a photopic wavelength of 550 nm. But further improvement in color-bleach kinetics and reproducibility of redox behavior is desirable to broaden their spectrum of utility

Micellar Catalysis of Diels-Alder Reactions : Substrate Positioning in the Micelle

NARCIS (Netherlands)

Rispens, Theo; Engberts, Jan B.F.N.

2002-01-01

We have studied the kinetics of the Diels-Alder reactions of cyclopentadiene, sorbyl alcohol, and sorbyltrimethylammonium bromide with a series of N-substituted maleimides in micellar media. Micellar rate constants have been determined and were found to be 20-40 times lower than the respective

Study of the Reaction 2-(p-Nitrophenylethyl Bromide + OH− in Dimeric Micellar Solutions

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María Luisa Moyá

2011-11-01

Full Text Available The dehydrobromination reaction 2-(p-nitrophenylethyl bromide + OH− was investigated in several alkanediyl-a-w-bis(dodecyldimethylammonium bromide, 12-s-12,2Br− (with s = 2, 3, 4, 5, 6, 8, 10, 12 micellar solutions, in the presence of NaOH 5 × 10−3 M. The kinetic data were quantitatively rationalized within the whole surfactant concentration range by using an equation based on the pseudophase ion-exchange model and taking the variations in the micellar ionization degree caused by the morphological transitions into account. The agreement between the theoretical and the experimental data was good in all the dimeric micellar media studied, except for the 12-2-12,2Br− micellar solutions. In this case, the strong tendency to micellar growth shown by the 12-2-12,2Br− micelles could be responsible for the lack of accordance. Results showed that the dimeric micelles accelerate the reaction more than two orders of magnitude as compared to water.

Phase separation in living micellar networks

Science.gov (United States)

Cristobal, G.; Rouch, J.; Curély, J.; Panizza, P.

We present a lattice model based on two n→0 spin vectors, capable of treating the thermodynamics of living networks in micellar solutions at any surfactant concentration. We establish an isomorphism between the coupling constants in the two spin vector Hamiltonian and the surfactant energies involved in the micellar situation. Solving this Hamiltonian in the mean-field approximation allows one to calculate osmotic pressure, aggregation number, free end and cross-link densities at any surfactant concentration. We derive a phase diagram, including changes in topology such as the transition between spheres and rods and between saturated and unsaturated networks. A phase separation can be found between a saturated network and a dilute solution composed of long flexible micelles or a saturated network and a solution of spherical micelles.

Matrix-assisted laser desorption/ionization mass spectrometric analysis of poly(3,4-ethylenedioxythiophene) in solid-state dye-sensitized solar cells: comparison of in situ photoelectrochemical polymerization in aqueous micellar and organic media.

Science.gov (United States)

Zhang, Jinbao; Ellis, Hanna; Yang, Lei; Johansson, Erik M J; Boschloo, Gerrit; Vlachopoulos, Nick; Hagfeldt, Anders; Bergquist, Jonas; Shevchenko, Denys

2015-04-07

Solid-state dye-sensitized solar cells (sDSCs) are devoid of such issues as electrolyte evaporation or leakage and electrode corrosion, which are typical for traditional liquid electrolyte-based DSCs. Poly(3,4-ethylenedioxythiophene) (PEDOT) is one of the most popular and efficient p-type conducting polymers that are used in sDSCs as a solid-state hole-transporting material. The most convenient way to deposit this insoluble polymer into the dye-sensitized mesoporous working electrode is in situ photoelectrochemical polymerization. Apparently, the structure and the physicochemical properties of the generated conducting polymer, which determine the photovoltaic performance of the corresponding solar cell, can be significantly affected by the preparation conditions. Therefore, a simple and fast analytical method that can reveal information on polymer chain length, possible chemical modifications, and impurities is strongly required for the rapid development of efficient solar energy-converting devices. In this contribution, we applied matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) for the analysis of PEDOT directly on sDSCs. It was found that the PEDOT generated in aqueous micellar medium possesses relatively shorter polymeric chains than the PEDOT deposited from an organic medium. Furthermore, the micellar electrolyte promotes a transformation of one of the thiophene terminal units to thiophenone. The introduction of a carbonyl group into the PEDOT molecule impedes the growth of the polymer chain and reduces the conductivity of the final polymer film. Both the simplicity of sample preparation (only application of the organic matrix onto the solar cell is needed) and the rapidity of analysis hold the promise of making MALDI MS an essential tool for the physicochemical characterization of conducting polymer-based sDSCs.

Preparation and in vitro evaluation of folate-receptor-targeted SPION-polymer micelle hybrids for MRI contrast enhancement in cancer imaging

Science.gov (United States)

Mahajan, Shveta; Koul, Veena; Choudhary, Veena; Shishodia, Gauri; Bharti, Alok C.

2013-01-01

Polymer-SPION hybrids were investigated for receptor-mediated localization in tumour tissue. Superparamagnetic iron oxide nanoparticles (SPIONs) prepared by high-temperature decomposition of iron acetylacetonate were monodisperse (9.27 ± 3.37 nm), with high saturation magnetization of 76.8 emu g-1. Amphiphilic copolymers prepared from methyl methacrylate and PEG methacrylate by atom transfer radical polymerization were conjugated with folic acid (for folate-receptor specificity). The folate-conjugated polymer had a low critical micellar concentration (0.4 mg l-1), indicating stability of the micellar formulation. SPION-polymeric micelle clusters were prepared by desolvation of the SPION dispersion/polymer solution in water. Magnetic resonance imaging of the formulation revealed very good contrast enhancement, with transverse (T2) relaxivity of 260.4 mM-1 s-1. The biological evaluation of the SPION micelles included cellular viability assay (MTT) and uptake in HeLa cells. These studies demonstrated the potential use of these nanoplatforms for imaging and targeting.

Au/CdS Hybrid Nanoparticles in Block Copolymer Micellar Shells.

Science.gov (United States)

Koh, Haeng-Deog; Changez, Mohammad; Lee, Jae-Suk

2010-10-18

A polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) micellar structure with a P2VP core containing 5 nm CdS nanoparticles (NPs) and a PS shell formed in toluene that is a good solvent for PS block undergoes the core-shell inversion by excess addition of methanol that is a good solvent for P2VP block. It leads to the formation of micellar shell-embedded CdS NPs in the methanol major phase. The spontaneous crystalline growth of Au NPs on the CdS surfaces positioned at micellar shells without a further reduction process is newly demonstrated. The nanostructure of Au/CdS/PS-b-P2VP hybrid NPs is confirmed by transmission electron microscopy, energy-dispersive X-ray, and UV-Vis absorption. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Stable curcumin-loaded polymeric micellar formulation for enhancing cellular uptake and cytotoxicity to FLT3 overexpressing EoL-1 leukemic cells.

Science.gov (United States)

Tima, Singkome; Anuchapreeda, Songyot; Ampasavate, Chadarat; Berkland, Cory; Okonogi, Siriporn

2017-05-01

The present study aims to develop a stable polymeric micellar formulation of curcumin (CM) with improved solubility and stability, and that is suitable for clinical applications in leukemia patients. CM-loaded polymeric micelles (CM-micelles) were prepared using poloxamers. The chemical structure of the polymers influenced micellar properties. The best formulation of CM-micelles, namely CM-P407, was obtained from poloxamer 407 at drug to polymer ratio of 1:30 and rehydrated with phosphate buffer solution pH 7.4. CM-P407 exhibited the smallest size of 30.3±1.3nm and highest entrapment efficiency of 88.4±4.1%. When stored at -80°C for 60days, CM-P407 retained high protection of CM and had no significant size change. In comparison with CM solution in dimethyl sulfoxide (CM-DMSO), CM kinetic degradation in both formulations followed a pseudo-first-order reaction, but the half-life of CM in CM-P407 was approx. 200 times longer than in CM-DMSO. Regarding the activity against FLT3 overexpressing EoL-1 leukemic cells, CM-P407 showed higher cytotoxicity than CM-DMSO. Moreover, intracellular uptake to leukemic cells of CM-P407 was 2-3 times greater than that of CM-DMSO. These promising results for CM-P407 will be further investigated in rodents and in clinical studies for leukemia treatment. Copyright © 2017 Elsevier B.V. All rights reserved.

Projections for the Production of Bulk Volume Bio-Based Polymers in Europe and Environmental Implications

NARCIS (Netherlands)

Patel, M.K.; Crank, M.

2007-01-01

In this paper we provide an overview of the most important emerging groups of bio-based polymers for bulk volume applications and we discuss market projections for these types of bio-based polymers in the EU, thereby distinguishing between three scenarios. Bio-based polymers are projected to reach a

PH-triggered micellar membrane for controlled release microchips

KAUST Repository

Yang, Xiaoqiang

2011-01-01

A pH-responsive membrane based on polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) block copolymer was developed on a model glass microchip as a promising controlled polymer delivery system. The PS-b-P4VP copolymer assembles into spherical and/or worm-like micelles with styrene block cores and pyridine coronas in selective solvents. The self-assembled worm-like morphology exhibited pH-responsive behaviour due to the protonation of the P4VP block at low pH and it\\'s deprotonation at high pH and thus constituting a switchable "off/on" system. Doxorubicin (Dox) was used as cargo to test the PS-b-P4VP membrane. Luminescence experiments indicated that the membrane was able to store Dox molecules within its micellar structure at neutral pH and then release them as soon as the pH was raised to 8.0. The performance of the cast membrane was predictable and most importantly reproducible. The physiochemical and biological properties were also investigated carefully in terms of morphology, cell viability and cell uptake. This journal is © The Royal Society of Chemistry.

Impact of thermooxidation of phytosteryl and phytostanyl fatty acid esters on cholesterol micellarization in vitro.

Science.gov (United States)

Scholz, Birgit; Weiherer, Renate; Engel, Karl-Heinz

2017-09-01

The effects of thermooxidation of a phytosteryl/-stanyl and a phytostanyl fatty acid ester mixture on cholesterol micellarization were investigated using an in vitro digestion model simulating enzymatic hydrolysis by cholesterol esterase and subsequent competition of the liberated phytosterols/-stanols with cholesterol for incorporation into mixed micelles. As a first step, relationships between different doses of the ester mixtures and the resulting micellarized cholesterol were established. Subsequent subjection of the thermooxidized ester mixtures to the in vitro digestion model resulted in three principal observations: (i) thermal treatment of the ester mixtures led to substantial decreases of the intact esters, (ii) in vitro digestion of cholesterol in the presence of the thermooxidized ester mixtures resulted in significant increases of cholesterol micellarization, and (iii) the extents of the observed effects on cholesterol micellarization were strongly associated to the remaining contents of intact esters. The loss of efficacy to inhibit cholesterol micellarization due to thermally induced losses of intact esters corresponded to a loss of efficacy that would have been induced by an actual removal of these amounts of esters prior to the in vitro digestion. The obtained results suggest that in particular oxidative modifications of the fatty acid moieties might be responsible for the observed increases of cholesterol micellarization. Copyright © 2017 Elsevier Inc. All rights reserved.

Interaction of multiple biomimetic antimicrobial polymers with model bacterial membranes

Energy Technology Data Exchange (ETDEWEB)

Baul, Upayan, E-mail: upayanb@imsc.res.in; Vemparala, Satyavani, E-mail: vani@imsc.res.in [The Institute of Mathematical Sciences, C.I.T. Campus, Taramani, Chennai 600113 (India); Kuroda, Kenichi, E-mail: kkuroda@umich.edu [Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, Michigan 48109 (United States)

2014-08-28

Using atomistic molecular dynamics simulations, interaction of multiple synthetic random copolymers based on methacrylates on prototypical bacterial membranes is investigated. The simulations show that the cationic polymers form a micellar aggregate in water phase and the aggregate, when interacting with the bacterial membrane, induces clustering of oppositely charged anionic lipid molecules to form clusters and enhances ordering of lipid chains. The model bacterial membrane, consequently, develops lateral inhomogeneity in membrane thickness profile compared to polymer-free system. The individual polymers in the aggregate are released into the bacterial membrane in a phased manner and the simulations suggest that the most probable location of the partitioned polymers is near the 1-palmitoyl-2-oleoyl-phosphatidylglycerol (POPG) clusters. The partitioned polymers preferentially adopt facially amphiphilic conformations at lipid-water interface, despite lacking intrinsic secondary structures such as α-helix or β-sheet found in naturally occurring antimicrobial peptides.

The magnetoviscous effect of micellar solutions doped with water based ferrofluids

Energy Technology Data Exchange (ETDEWEB)

Arantes, Fabiana R., E-mail: farantes@if.usp.br [Institute of Physics, University of Sao Paulo (Brazil); Institute of Fluid Mechanics, Technische Universität Dresden (Germany); Odenbach, Stefan, E-mail: stefan.odenbach@tu-dresden.de [Institute of Fluid Mechanics, Technische Universität Dresden (Germany)

2015-09-15

This work presents a magnetorheological study of micellar solutions of potassium laurate and water doped with magnetite nanoparticles, accompanied by auxiliary dynamic light scattering measurements. An increase in the viscosity of the samples under applied field was observed and, furthermore, a considerable magnetoviscous effect was revealed even at magnetic particles' concentrations as low as 0.005–0.01 vol%. This indicates that the rheological behavior of the micelles is changed by the interaction of the magnetic particles with the applied field, leading to different microscopic arrangements in the micellar solutions. - Highlights: • We study the magnetorheological behavior of micellar solutions doped with ferrofluids. • We observe an increase in the viscosity of the samples under an applied field. • We find a large magnetoviscous effect even at low magnetic particles' concentration. • Interaction of particles with the field changes the micelles' rheological behavior.

Molecular motion of micellar solutes: a 13C NMR relaxation study

International Nuclear Information System (INIS)

Stark, R.E.; Kasakevich, M.L.; Granger, J.W.

1982-01-01

A series of simple NMR relaxation experiments have been performed on nitrobenzene and aniline dissolved in the ionic detergents sodium dodecyl sulfate (SDS) and hexadecyltrimethylammonium bromide (CTAB). Using 13 C relaxation rates at various molecular sites, and comparing data obtained in organic media with those for micellar solutions, the viscosity at the solubilization site was estimated and a detailed picture of motional restrictions imposed by the micellar enviroment was derived. Viscosities of 8 to 17 cp indicate a rather fluid environment for solubilized nitrobenzene; both additives exhibit altered motional preferences in CTAB solutions only. As an aid in interpretation of the NMR data, quasi-elastic light scattering and other physical techniques have been used to evaluate the influence of organic solutes on micellar size and shape. The NMR methods are examined critically in terms of their general usefulness for studies of solubilization in detergent micelles. 48 references

Stepwise dynamics of an anionic micellar film - Formation of crown lenses.

Science.gov (United States)

Lee, Jongju; Nikolov, Alex; Wasan, Darsh

2017-06-15

We studied the stepwise thinning of a microscopic circular foam film formed from an anionic micellar solution of sodium dodecyl sulfate (SDS). The foam film formed from the SDS micellar solution thins in a stepwise manner by the formation and expansion of a dark spot(s) of one layer less than the film thickness. During the last stages of film thinning (e.g., a film with one micellar layer), the dark spot expansion occurs via two steps. Initially, a small dark circular spot inside a film of several microns in size is formed, which expands at a constant rate. Then, a ridge along the expanding spot is formed. As the ridge grows, it becomes unstable and breaks into regular crown lenses, which are seen as white spots in the reflected light at the border of the dark spot with the surrounding thicker film. The Rayleigh type of instability contributes to the formation of the lenses, which results in the increase of the dark spot expansion rate with time. We applied the two-dimensional micellar-vacancy diffusion model and took into consideration the effects of the micellar layering and film volume on the rate of the dark spot expansion [Lee et al., 2016] to predict the rate of the dark spot expansion for a 0.06M SDS film in the presence of lenses. We briefly discuss the Rayleigh type of instability in the case of a 0.06M SDS foam film. The goals of this study are to reveal why the crown lenses are formed during the foam film stratification and to elucidate their effect on the rate of spot expansion. Copyright © 2017 Elsevier Inc. All rights reserved.

Micellar liquid chromatography

International Nuclear Information System (INIS)

Basova, Elena M; Ivanov, Vadim M; Shpigun, Oleg A

1999-01-01

Background and possibilities of practical applications of micellar liquid chromatography (MLC) are considered. Various retention models in MLC, the effects of the nature and concentration of surfactants and organic modifiers, pH, temperature and ionic strength on the MLC efficiency and selectivity are discussed. The advantages and limitations of MLC are demonstrated. The performance of MLC is critically evaluated in relationship to the reversed-phase HPLC and ion-pair chromatography. The potential of application of MLC for the analysis of pharmaceuticals including that in biological fluids and separation of inorganic anions, transition metal cations, metal chelates and heteropoly compounds is described. The bibliography includes 146 references.

Encapsulation and covalent binding of molecular payload in enzymatically activated micellar nanocarriers.

Science.gov (United States)

Rosenbaum, Ido; Harnoy, Assaf J; Tirosh, Einat; Buzhor, Marina; Segal, Merav; Frid, Liat; Shaharabani, Rona; Avinery, Ram; Beck, Roy; Amir, Roey J

2015-02-18

The high selectivity and often-observed overexpression of specific disease-associated enzymes make them extremely attractive for triggering the release of hydrophobic drug or probe molecules from stimuli-responsive micellar nanocarriers. Here we utilized highly modular amphiphilic polymeric hybrids, composed of a linear hydrophilic polyethylene glycol (PEG) and an esterase-responsive hydrophobic dendron, to prepare and study two diverse strategies for loading of enzyme-responsive micelles. In the first type of micelles, hydrophobic coumarin-derived dyes were encapsulated noncovalently inside the hydrophobic core of the micelle, which was composed of lipophilic enzyme-responsive dendrons. In the second type of micellar nanocarrier the hydrophobic molecular cargo was covalently linked to the end-groups of the dendron through enzyme-cleavable bonds. These amphiphilic hybrids self-assembled into micellar nanocarriers with their cargo covalently encapsulated within the hydrophobic core. Both types of micelles were highly responsive toward the activating enzyme and released their molecular cargo upon enzymatic stimulus. Importantly, while faster release was observed with noncovalent encapsulation, higher loading capacity and slower release rate were achieved with covalent encapsulation. Our results clearly indicate the great potential of enzyme-responsive micellar delivery platforms due to the ability to tune their payload capacities and release rates by adjusting the loading strategy.

Studies for the use of water soluble chelating polymer in ultra-filtration technique for the removal of uranium from aqueous solutions

International Nuclear Information System (INIS)

Misra, S.K.; Mahatele, A.K.; Tripathi, S.C.; Vijayan, K.; Munshi, S.K.

2005-01-01

Studies were carried out for the removal of uranium from aqueous medium using water soluble chelating polymer by ultra-filtration technique. The water soluble polymers are the option for the surfactants used in the micellar enhanced ultra-filtration technique. More than 95% separation of uranium carried out under different experimental conditions, suggest that the technique can be effectively employed for the removal uranium from the aqueous effluent streams. (author)

Photonics of dyes molecules in reverse micellar solution

International Nuclear Information System (INIS)

Ibragimova, M.R.; Laurinas, V.Ch.

2001-01-01

Spectral luminescent characteristics of the dye acridine orange and eosin has been studied in reverse micellar solutions of sodium bis(2-ethyl-hexyl)sulfosuccinate. It was shown that the increase of the nucleus volume of reverse micelles. (author)

Modification of silica surface by gamma ray induced Ad micellar Polymerization

International Nuclear Information System (INIS)

Buathong, Salukjit; Pongprayoon, Thirawudh; Suwanmala, Phiriyatorn

2005-10-01

Precipitated silica is often added to natural rubber compounds in order to improve performance in commercial application. A problem with using silica as filler is the poor compatibility between silica and natural rubber. In this research, polyisoprene was coated on silica surface by gamma ray induced ad micellar polymerization in order to achieve the better compatibility between silica and natural rubber. The modified silica was characterized by FT-IR, and SEM. The results show that polyisoprene was successfully coated on silica surface via gamma ray induced ad micellar polymerization

Redox reactions in micellar systems. communication 4. Eosin-photosensitized reduction of methylviologen

Energy Technology Data Exchange (ETDEWEB)

Nadtochenko, V.; Dzhabiev, T.S.; Rubtsov, I.V.

1985-12-10

The authors present data on photosensitized reduction of methylviologen (MV/sup 2 +/) by disodium ethylenediaminetetraacetate (EDTA) in micellar systems modeling, in a first approximation, the structural organization of components of the chain of energy and electron transfer in natural photosynthesis. Photosensitized reduction of methylviologen by EDTA in micellar solutions can model photosystem I of plants with structure formation of reagents and transfer of excitation energy before the step of occurrence of a redox reaction in the active center.

Effect of ripening, heat processing, and fat type on the micellarization of pigments from jalapeño peppers.

Science.gov (United States)

Victoria-Campos, Claudia I; Ornelas-Paz, José de Jesús; Yahia, Elhadi M; Jiménez-Castro, Jorge A; Cervantes-Paz, Braulio; Ibarra-Junquera, Vrani; Pérez-Martínez, Jaime David; Zamudio-Flores, Paul B; Escalante-Minakata, Pilar

2013-10-16

Raw and heat-processed (boiled and grilled) jalapeño peppers at three intermediate ripening stages (brown, 50% red, and 75% red) were digested in vitro without fat and in the presence of soybean oil (SO) or beef tallow (BT), and the micellarization of their lipid soluble pigments (LSP) was measured. The micelles from digestions with brown, 50% red, and 75% red peppers contained up to 27, 35, and 29 different LSP, respectively. Boiling and grilling decreased the micellarization of LSP from brown peppers, whereas the opposite was observed with 75% red peppers. Heat processing did not clearly affect the micellarization of LSP from 50% red fruits. The impact of fat on LSP micellarization was ripening-dependent, but the micellarization of the less polar carotenoids was always increased by SO or BT. This positive effect of fat was higher with SO than with BT.

Preparation and in vitro evaluation of folate-receptor-targeted SPION–polymer micelle hybrids for MRI contrast enhancement in cancer imaging

International Nuclear Information System (INIS)

Mahajan, Shveta; Choudhary, Veena; Koul, Veena; Shishodia, Gauri; Bharti, Alok C

2013-01-01

Polymer–SPION hybrids were investigated for receptor-mediated localization in tumour tissue. Superparamagnetic iron oxide nanoparticles (SPIONs) prepared by high-temperature decomposition of iron acetylacetonate were monodisperse (9.27 ± 3.37 nm), with high saturation magnetization of 76.8 emu g −1 . Amphiphilic copolymers prepared from methyl methacrylate and PEG methacrylate by atom transfer radical polymerization were conjugated with folic acid (for folate-receptor specificity). The folate-conjugated polymer had a low critical micellar concentration (0.4 mg l −1 ), indicating stability of the micellar formulation. SPION–polymeric micelle clusters were prepared by desolvation of the SPION dispersion/polymer solution in water. Magnetic resonance imaging of the formulation revealed very good contrast enhancement, with transverse (T 2 ) relaxivity of 260.4 mM −1 s −1 . The biological evaluation of the SPION micelles included cellular viability assay (MTT) and uptake in HeLa cells. These studies demonstrated the potential use of these nanoplatforms for imaging and targeting. (paper)

Critical phenomena and polymer coil-to-globule transition

International Nuclear Information System (INIS)

Chu, B.; Xu Renliang; Wang Zhulun; Zuo Ju

1988-01-01

Small-angle scattering techniques including laser light scattering (LLS), small-angle X-ray scattering (SAXS) and small-angle neutron scattering (SANS) have been useful tools to measure the static and dynamic properties (in terms of critical fluctuations) of fluids, fluid mixtures, polymer and micellar solutions, polymer blends and metallic alloys. A brief review is given of recent results in critical-phenomena experiments using small-angle scattering techniques. Topics of current interest are pointed out, and a guide to the vast literature on critical opalescence is provided. Coil-to-globule transition in polymer solutions has been a classic experimental challenge over the past decade. In order to succeed in reaching the collapsed regime, it becomes important to realize that single coil contraction of a linear polymer molecule in solution takes place in the neighborhood of phase separations. By using the recent development of a small-angle light-scattering spectrometer and by taking advantage of a successful polymer fractionation experiment, the transition behavior of linear polystyrene in cyclohexane from the Θ state to the collapsed regime can be characterized based on both the radius of gyration and the hydrodynamic radius. (orig.)

Self-Assembled Nanocarriers Based on Amphiphilic Natural Polymers for Anti- Cancer Drug Delivery Applications.

Science.gov (United States)

Sabra, Sally; Abdelmoneem, Mona; Abdelwakil, Mahmoud; Mabrouk, Moustafa Taha; Anwar, Doaa; Mohamed, Rania; Khattab, Sherine; Bekhit, Adnan; Elkhodairy, Kadria; Freag, May; Elzoghby, Ahmed

2017-01-01

Micellization provides numerous merits for the delivery of water insoluble anti-cancer therapeutic agents including a nanosized 'core-shell' drug delivery system. Recently, hydrophobically-modified polysaccharides and proteins are attracting much attention as micelle forming polymers to entrap poorly soluble anti-cancer drugs. By virtue of their small size, the self-assembled micelles can passively target tumor tissues via enhanced permeation and retention effect (EPR). Moreover, the amphiphilic micelles can be exploited for active-targeted drug delivery by attaching specific targeting ligands to the outer micellar hydrophilic surface. Here, we review the conjugation techniques, drug loading methods, physicochemical characteristics of the most important amphiphilic polysaccharides and proteins used as anti-cancer drug delivery systems. Attention focuses on the mechanisms of tumor-targeting and enhanced anti-tumor efficacy of the encapsulated drugs. This review will highlight the remarkable advances of hydrophobized polysaccharide and protein micelles and their potential applications as anti-cancer drug delivery nanosystems. Micellar nanocarriers fabricated from amphiphilic natural polymers hold great promise as vehicles for anti-cancer drugs. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

First Example of a Lipophilic Porphyrin-Cardanol Hybrid Embedded in a Cardanol-Based Micellar Nanodispersion

Directory of Open Access Journals (Sweden)

Giuseppe Vasapollo

2012-10-01

Full Text Available Cardanol is a natural and renewable organic raw material obtained as the major chemical component by vacuum distillation of cashew nut shell liquid. In this work a new sustainable procedure for producing cardanol-based micellar nanodispersions having an embedded lipophilic porphyrin itself peripherally functionalized with cardanol substituents (porphyrin-cardanol hybrid has been described for the first time. In particular, cardanol acts as the solvent of the cardanol hybrid porphyrin and cholesterol as well as being the main component of the nanodispersions. In this way a “green” micellar nanodispersion, in which a high percentage of the micellar system is derived from renewable “functional” molecules, has been produced.

Fundamental Characterization of the Micellar Self-Assembly of Sophorolipid Esters.

Science.gov (United States)

Koh, Amanda; Todd, Katherine; Sherbourne, Ezekiel; Gross, Richard A

2017-06-13

Surfactants are ubiquitous constituents of commercial and biological systems that function based on complex structure-dependent interactions. Sophorolipid (SL) n-alkyl esters (SL-esters) comprise a group of modified naturally derived glycolipids from Candida bombicola. Herein, micellar self-assembly behavior as a function of SL-ester chain length was studied. Surface tensions as low as 31.2 mN/m and critical micelle concentrations (CMCs) as low as 1.1 μM were attained for diacetylated SL-decyl ester (dASL-DE) and SL-octyl ester, respectively. For deacetylated SL-esters, CMC values reach a lower limit at SL-ester chains above n-butyl (SL-BE, 1-3 μM). This behavior of SL-esters with increasing hydrophobic tail length is unlike other known surfactants. Diffusion-ordered spectroscopy (DOSY) and T 1 relaxation NMR experiments indicate this behavior is due to a change in intramolecular interactions, which impedes the self-assembly of SL-esters with chain lengths above SL-BE. This hypothesis is supported by micellar thermodynamics where a disruption in trends occurs at n-alkyl ester chain lengths above those of SL-BE and SL-hexyl ester (SL-HE). Diacetylated (dA) SL-esters exhibit an even more unusual trend in that CMC increases from 1.75 to 815 μM for SL-ester chain lengths of dASL-BE and dASL-DE, respectively. Foaming studies, performed to reveal the macroscopic implications of SL-ester micellar behavior, show that the observed instability in foams formed using SL-esters are due to coalescence, which highlights the importance of understanding intermicellar interactions. This work reveals that SL-esters are an important new family of green high-performing surfactants with unique structure-property relationships that can be tuned to optimize micellar characteristics.

Effect of the interaction of heat-processing style and fat type on the micellarization of lipid-soluble pigments from green and red pungent peppers (Capsicum annuum).

Science.gov (United States)

Victoria-Campos, Claudia I; Ornelas-Paz, José de Jesús; Yahia, Elhadi M; Failla, Mark L

2013-04-17

The high diversity of carotenoids and chlorophylls in foods contrasts with the reduced number of pigments that typically are investigated in micellarization studies. In this study, pepper samples (raw and heat-treated) contained 68 individual pigments, but only 38 of them were micellarized after in vitro digestion. The micellarization of pigments was majorly determined by the interaction effect of processing style (food matrix effect) and fat type (saturated and unsaturated). The highest micellarization was observed with raw peppers. Unsaturated fat increased the micellarization of carotenoid esters, while the impact of fat on the micellarization of free carotenoids seemed to be dependent on pigment structure. The micellarization efficiency was diminished as the esterification level of carotenoids increased. The type of fatty acid moiety and the polarity of the carotenoids modulated their micellarization. Chlorophylls were transformed into pheophytins by heat-processing and digestion, with the pheophytins being stable under gastrointestinal conditions. Micellarization of pheophytins was improved by fat.

Glutathione transferase mimics : Micellar catalysis of an enzymic reaction

NARCIS (Netherlands)

Lindkvist, Björn; Weinander, Rolf; Engman, Lars; Koetse, Marc; Engberts, Jan B.F.N.; Morgenstern, Ralf

1997-01-01

Substances that mimic the enzyme action of glutathione transferases (which serve in detoxification) are described. These micellar catalysts enhance the reaction rate between thiols and activated halogenated nitroarenes as well as alpha,beta-unsaturated carbonyls. The nucleophilic aromatic

pH multistage responsive micellar system with charge-switch and PEG layer detachment for co-delivery of paclitaxel and curcumin to synergistically eliminate breast cancer stem cells.

Science.gov (United States)

Yang, Zhe; Sun, Na; Cheng, Rui; Zhao, Chenyang; Liu, Zerong; Li, Xian; Liu, Jie; Tian, Zhongmin

2017-12-01

Several studies have demonstrated that cancer stem cells (CSCs) are responsible for replenishing bulk tumor cells, generating new tumors and causing metastasis and relapse. Although combination therapy with multiple chemotherapeutics is considered to be a promising approach for simultaneously eliminating non-CSCs and CSCs, it is difficult to deliver drugs into the inner region of a solid tumor where the CSCs are located due to a lack of capillaries. Here, we synthesized a pH-sensitive polymer, poly(ethylene glycol)-benzoic imine-poly(γ-benzyl-l-aspartate)-b-poly(1-vinylimidazole) block copolymer (PPBV), to develop a pH multistage responsive micellar system for co-delivering paclitaxel and curcumin and synergistically eliminating breast cancer stem cells (bCSCs) and non-bCSCs. This pH multistage responsive micellar system could intelligently switch its surface charge from neutral to positive, de-shield its PEG layer and reduce its size after long-circulation and extravasation from leaky blood vessels at tumor sites, thus facilitating their cellular uptake and deep tumor penetration. These advantages were also beneficial for the combinational therapy efficacy of PTX and CUR to reach the maximum level and achieve superior tumor inhibition activity and effective bCSCs-killing capacity in vivo. Consequently, this pH multistage responsive micellar system is a powerful platform for collaborative therapy with PTX and CUR to simultaneously eliminate bCSCs and non-CSCs. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ordering fluctuations in a shear-banding wormlike micellar system

DEFF Research Database (Denmark)

Angelico, R.; Rossi, C. Oliviero; Ambrosone, L.

2010-01-01

We present a first investigation about the non-linear flow properties and transient orientational-order fluctuations observed in the shear-thinning lecithin–water–cyclohexane wormlike micellar system at a concentration near to the zero-shear isotropic–nematic phase transition. From rheological...

One electron reduction of acridine orange studied in aqueous micellar medium using pulse radiolysis technique

International Nuclear Information System (INIS)

Goel, Anjali; Guha, S.N.

1994-01-01

Absorption spectrum, decay and formation kinetics of semi reduced species formed by the reaction of hydrated electron (e aq - ) with acridine orange (AO) were evaluated in sodium lauryl sulphate (SLS) micellar medium. Fluorescence and absorption properties of AO were also studied in this micellar system. The results were compared with those in homogenous aqueous medium. (author). 2 refs., 2 figs

El Dorado Micellar-Polymer Demonstration Project. Second annual report, July 1975--May 1976

Energy Technology Data Exchange (ETDEWEB)

Rosenwald, G.W. (ed.)

1976-07-01

Laboratory oil displacement tests were conducted using Shell Oil Co. and Union Oil Co. chemical formulations in both Berea and El Dorado Admire Sandstone cores. Total relative mobility of the oil-water bank created during chemical flooding was measured in Admire Sandstone cores. The values ranged from 0.018 to 0.065 reciprocal centipoise. Four observation wells were drilled, cored, and logged during the year. They were cased with fiberglass and are now being used to monitor fluid properties. A tracer test was conducted by injection of chemical tracers into each of the 18 injection wells. Results indicate that there is no gross channeling in the reservoir. The same conclusion was drawn from results of interference tests. Performance forecasting was utilized to show that maintaining the bottom-hole injection pressures at 400 psia and the producing pressures at 30 psia would increase throughput rates and result in acceptable project life for the 6.4-acre, five-spot patterns. Injection well rates relative to the central injector were computed. These rates will be used as a guide for the operation of injection wells. This plan corresponds to operation at constant bottom-hole pressures for a homogeneous reservoir of uniform thickness. Construction of the fresh water system and injection plant was completed. The injection plant has performed satisfactorily. Injection of pretreatment fluid was started in both patterns on November 18, 1975.Severe loss of injectivity was experienced during the first week of injection. Several likely causes were identified and corrective actions taken. More moderate injectivity problems have continued throughout this reporting period. Additional preventive measures have been undertaken to improve the quality of injected fluids. A procedure was developed to stimulate and clean-up wells damaged by the injection fluid. A preliminary evaluation indicates that combination solvent-acid treatments will increase injection rates to the desired level.

Study of micellar solutions of the 'sodium lauryl sulphate-heavy water' system by using pulsed NMR

International Nuclear Information System (INIS)

Fouchet, C.

1972-01-01

This research thesis reports the study of the nuclear magnetic resonance of protons contained by micellar solutions of sodium lauryl sulphate and heavy water. Relaxation times have been measured with respect to various parameters: concentration, temperature, frequency. The author presents the main properties of micellar solutions and indicate the various possible movements. Then, he addresses the implemented technique, and shows that NMR is sensitive to short range interactions, and allows micellar movements to be studied over an extended rate range. Experimental results are then presented and interpreted [fr

Fluorescence spectroscopic studies on substituted porphyrins in homogeneous solvents and cationic micellar medium

International Nuclear Information System (INIS)

Phukan, Smritakshi; Mishra, Bhupendra; Chandra Shekar, K.P.; Kumar, Anil; Kumar, Dalip; Mitra, Sivaprasad

2013-01-01

Steady state and time-resolved fluorescence properties of porphyrin appended 1,3,4-oxadiazoles and thiazoles were described in homogeneous medium as well as in presence of cationic surfactant cetyltrimethylammonium bromide (CTAB). The electron withdrawing substituent on the porphyrin moiety in both the cases make a donor–spacer–acceptor type of intramolecular photoinduced electron transfer (PET) system resulting substantial quenching in porphyrin fluorescence due to partial energy migration towards the acceptor in the excited state. The increase in fluorescence yield as well as appreciable difference in fluorescence decay behavior in aqueous buffer solution of pH 4.2 from that in chloroform solution is believed due to partial protonation of the porphyrin ring. All the investigated systems show preferential binding into the interfacial region of the micellar sub-domain with varying degree of penetration depending on the nature of the substituent. Almost 2–4 fold increase in fluorescence yield for the probes is explained on the basis of restricted flexibility and corresponding decrease in total nonradiative rate inside the micellar interface layer. - Highlights: ► Synthesis and detail fluorescence studies of a series of porphyrin appended 1,3,4-oxadiazoles and thiazoles. ► Comparison of homogeneous solvent study with that in CTAB. ► Substantial porphyrin fluorescence quenching in donor–spacer–acceptor type system. ► Preferential binding of the substituted porphyrins in micellar sub-domain. ► Appreciable increase in fluorescence yield in micellar interface layer is due to decrease in total nonradiative rate.

A simplified radiometabolite analysis procedure for PET radioligands using a solid phase extraction with micellar medium

International Nuclear Information System (INIS)

Nakao, Ryuji; Halldin, Christer

2013-01-01

A solid phase extraction method has been developed for simple and high-speed direct determination of PET radioligands in plasma. Methods: This methodology makes use of a micellar medium and a solid-phase extraction cartridge for displacement of plasma protein bound radioligand and separation of PET radioligands from their radiometabolites without significant preparation. The plasma samples taken from monkey or human during PET measurements were mixed with a micellar eluent containing an anionic surfactant sodium dodecyl sulphate and loaded onto SPE cartridges. The amount of radioactivity corresponding to parent radioligand (retained on the cartridge) and its radioactive metabolites (eluted with micellar eluent) was measured. Results: Under the optimized conditions, excellent separation of target PET radioligands from their radiometabolites was achieved with a single elution and short run-time of 1 min. This method was successfully applied to study the metabolism for 11 C-labelled radioligands in human or monkey plasma. The amount of parent PET radioligands estimated by micellar solid phase extraction strongly corresponded with that determined by radio-LC. The improved throughput permitted the analysis of a large number of plasma samples (up to 13 samples per one PET study) for accurate estimation of metabolite-corrected input function during quantitative PET imaging studies. Conclusion: Solid phase extraction together with micellar medium is fast, sensitive and easy to use, and therefore it is an attractive alternative method to determine relative composition of PET radioligands in plasma

Energy transfer from triplet aromatic hydrocarbons to Tb3+ and Eu3+ in aqueous micellar solutions

International Nuclear Information System (INIS)

Almgren, M.; Grieser, F.; Thomas, J.K.

1979-01-01

The sensitization of Tb 3+ and Eu 3+ luminescence by energy transfer from aromatic triplet donors like naphthalene, bromonaphthalene, biphenyl, and phenanthrene in micellar sodium lauryl sulfate solution has been studied. Formal second-order rate constants for the energy transfer process in the micellar solutions were determined as 5 x 10 5 and 1.8 x 10 5 M -1 S -1 for transfer from biphenyl to Tb 3+ . The method of converting these rate constants to second-order constants pertaining to the micellar microenvironment is discussed; it is estimated that the transfer process at the micelles is charaterized by rate constants about one order of magnitude smaller than the formal ones. The transfer process is thus extremely slow. 7 figures

Complementary experimental-simulational study of surfactant micellar phase in the extraction process of metallic ions: Effects of temperature and salt concentration

Science.gov (United States)

Soto-Ángeles, Alan Gustavo; Rodríguez-Hidalgo, María del Rosario; Soto-Figueroa, César; Vicente, Luis

2018-02-01

The thermoresponsive micellar phase behaviour that exhibits the Triton-X-100 micelles by temperature effect and addition of salt in the extraction process of metallic ions was explored from mesoscopic and experimental points. In the theoretical study, we analyse the formation of Triton-X-100 micelles, load and stabilization of dithizone molecules and metallic ions extraction inside the micellar core at room temperature; finally, a thermal analysis is presented. In the experimental study, the spectrophotometric outcomes confirm the solubility of the copper-dithizone complex in the micellar core, as well as the extraction of metallic ions of aqueous environment via a cloud-point at 332.2 K. The micellar solutions with salt present a low absorbance value compared with the micellar solutions without salt. The decrease in the absorbance value is attributed to a change in the size of hydrophobic region of colloidal micelles. All transitory stages of extraction process are discussed and analysed in this document.

Ultrafast relaxation dynamics of a biologically relevant probe dansyl at the micellar surface.

Science.gov (United States)

Sarkar, Rupa; Ghosh, Manoranjan; Pal, Samir Kumar

2005-02-01

We report picosecond-resolved measurement of the fluorescence of a well-known biologically relevant probe, dansyl chromophore at the surface of a cationic micelle (cetyltrimethylammonium bromide, CTAB). The dansyl chromophore has environmentally sensitive fluorescence quantum yields and emission maxima, along with large Stokes shift. In order to study the solvation dynamics of the micellar environment, we measured the fluorescence of dansyl chromophore attached to the micellar surface. The fluorescence transients were observed to decay (with time constant approximately 350 ps) in the blue end and rise with similar timescale in the red end, indicative of solvation dynamics of the environment. The solvation correlation function is measured to decay with time constant 338 ps, which is much slower than that of ordinary bulk water. Time-resolved anisotropy of the dansyl chromophore shows a bi-exponential decay with time constants 413 ps (23%) and 1.3 ns (77%), which is considerably slower than that in free solvents revealing the rigidity of the dansyl-micelle complex. Time-resolved area-normalized emission spectroscopic (TRANES) analysis of the time dependent emission spectra of the dansyl chromophore in the micellar environment shows an isoemissive point at 21066 cm-1. This indicates the fluorescence of the chromophore contains emission from two kinds of excited states namely locally excited state (prior to charge transfer) and charge transfer state. The nature of the solvation dynamics in the micellar environments is therefore explored from the time-resolved anisotropy measurement coupled with the TRANES analysis of the fluorescence transients. The time scale of the solvation is important for the mechanism of molecular recognition.

Multicompartment micellar aggregates of linear ABC amphiphiles in solvents selective for the C block: A Monte Carlo simulation

KAUST Repository

Zhu, Yutian

2012-01-01

In the current study, we applied the Monte Carlo method to study the self-assembly of linear ABC amphiphiles composed of two solvophobic A and B blocks and a solvophilic C block. A great number of multicompartment micelles are discovered from the simulations and the detailed phase diagrams for the ABC amphiphiles with different block lengths are obtained. The simulation results reveal that the micellar structure is largely controlled by block length, solvent quality, and incompatibility between the different block types. When the B block is longer than or as same as the terminal A block, a rich variety of micellar structures can be formed from ABC amphiphiles. By adjusting the solvent quality or incompatibility between the different block types, multiple morphological transitions are observed. These morphological sequences are well explained and consistent with all the previous experimental and theoretical studies. Despite the complexity of the micellar structures and morphological transitions observed for the self-assembly of ABC amphiphiles, two important common features of the phase behavior are obtained. In general, the micellar structures obtained in the current study can be divided into zero-dimensional (sphere-like structures, including bumpy-surfaced spheres and sphere-on-sphere structures), one-dimensional (cylinder-like structures, including rod and ring structures), two-dimensional (layer-like structures, including disk, lamella and worm-like and hamburger structures) and three-dimensional (vesicle) structures. It is found that the micellar structures transform from low- to high- dimensional structures when the solvent quality for the solvophobic blocks is decreased. In contrast, the micellar structures transform from high- to low-dimensional structures as the incompatibility between different block types increases. Furthermore, several novel micellar structures, such as the CBABC five-layer vesicle, hamburger, CBA three-layer ring, wormlike shape with

Interaction of antihypertensive drug amiloride with metal ions in micellar medium using fluorescence spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Gujar, Varsha; Pundge, Vijaykumar; Ottoor, Divya, E-mail: divya@chem.unipune.ac.in

2015-05-15

Steady state and life time fluorescence spectroscopy have been employed to study the interaction of antihypertensive drug amiloride with biologically important metal ions i.e. Cu{sup 2+}, Fe{sup 2+}, Ni{sup 2+} and Zn{sup 2+} in various micellar media (anionic SDS (sodium dodecyl sulfate), nonionic TX-100 (triton X-100) and cationic CTAB (cetyl trimethyl ammonium bromide)). It was observed that fluorescence properties of drug remain unaltered in the absence of micellar media with increasing concentration of metal ions. However, addition of Cu{sup 2+}, Fe{sup 2+} and Ni{sup 2+} caused fluorescence quenching of amiloride in the presence of anionic micelle, SDS. Binding of drug with metal ions at the charged micellar interface could be the possible reason for this pH-dependent metal-mediated fluorescence quenching. There were no remarkable changes observed due to metal ions addition when drug was present in cationic and nonionic micellar medium. The binding constant and bimolecular quenching constant were evaluated and compared for the drug–metal complexes using Stern–Volmer equation and fluorescence lifetime values. - Highlights: • Interaction of amiloride with biologically important metal ions, Fe{sup 2+}, Cu{sup 2+}, Ni{sup 2+} and Zn{sup 2+}. • Monitoring the interaction in various micelle at different pH by fluorescence spectroscopy. • Micelles acts as receptor, amiloride as transducer and metal ions as analyte in the present system. • Interaction study provides pH dependent quenching and binding mechanism of drug with metal ions.

Interaction of antihypertensive drug amiloride with metal ions in micellar medium using fluorescence spectroscopy

International Nuclear Information System (INIS)

Gujar, Varsha; Pundge, Vijaykumar; Ottoor, Divya

2015-01-01

Steady state and life time fluorescence spectroscopy have been employed to study the interaction of antihypertensive drug amiloride with biologically important metal ions i.e. Cu 2+ , Fe 2+ , Ni 2+ and Zn 2+ in various micellar media (anionic SDS (sodium dodecyl sulfate), nonionic TX-100 (triton X-100) and cationic CTAB (cetyl trimethyl ammonium bromide)). It was observed that fluorescence properties of drug remain unaltered in the absence of micellar media with increasing concentration of metal ions. However, addition of Cu 2+ , Fe 2+ and Ni 2+ caused fluorescence quenching of amiloride in the presence of anionic micelle, SDS. Binding of drug with metal ions at the charged micellar interface could be the possible reason for this pH-dependent metal-mediated fluorescence quenching. There were no remarkable changes observed due to metal ions addition when drug was present in cationic and nonionic micellar medium. The binding constant and bimolecular quenching constant were evaluated and compared for the drug–metal complexes using Stern–Volmer equation and fluorescence lifetime values. - Highlights: • Interaction of amiloride with biologically important metal ions, Fe 2+ , Cu 2+ , Ni 2+ and Zn 2+ . • Monitoring the interaction in various micelle at different pH by fluorescence spectroscopy. • Micelles acts as receptor, amiloride as transducer and metal ions as analyte in the present system. • Interaction study provides pH dependent quenching and binding mechanism of drug with metal ions

Vertical structures in vibrated wormlike micellar solutions

Science.gov (United States)

Epstein, Tamir; Deegan, Robert

2008-11-01

Vertically vibrated shear thickening particulate suspensions can support a free-standing interfaces oriented parallel to gravity. We find that shear thickening worm-like micellar solutions also support such vertical interfaces. Above a threshold in acceleration, the solution spontaneously accumulates into a labyrinthine pattern characterized by a well-defined vertical edge. The formation of vertical structures is of interest because they are unique to shear-thickening fluids, and they indicate the existence of an unknown stress bearing mechanism.

Multiscale Modeling of the Effects of Salt and Perfume Raw Materials on the Rheological Properties of Commercial Threadlike Micellar Solutions.

Science.gov (United States)

Tang, Xueming; Zou, Weizhong; Koenig, Peter H; McConaughy, Shawn D; Weaver, Mike R; Eike, David M; Schmidt, Michael J; Larson, Ronald G

2017-03-23

We link micellar structures to their rheological properties for two surfactant body-wash formulations at various concentrations of salts and perfume raw materials (PRMs) using molecular simulations and micellar-scale modeling, as well as traditional surfactant packing arguments. The two body washes, namely, BW-1EO and BW-3EO, are composed of sodium lauryl ethylene glycol ether sulfate (SLEnS, where n is the average number of ethylene glycol repeat units), cocamidopropyl betaine (CAPB), ACCORD (which is a mixture of six PRMs), and NaCl salt. BW-3EO is an SLE3S-based body wash, whereas BW-1EO is an SLE1S-based body wash. Additional PRMs are also added into the body washes. The effects of temperature, salt, and added PRMs on micellar lengths, breakage times, end-cap free energies, and other properties are obtained from fits of the rheological data to predictions of the "Pointer Algorithm" [ Zou , W. ; Larson , R.G. J. Rheol. 2014 , 58 , 1 - 41 ], which is a simulation method based on the Cates model of micellar dynamics. Changes in these micellar properties are interpreted using the Israelachvili surfactant packing argument. From coarse-grained molecular simulations, we infer how salt modifies the micellar properties by changing the packing between the surfactant head groups, with the micellar radius remaining nearly constant. PRMs do so by partitioning to different locations within the micelles according to their octanol/water partition coefficient P OW and chemical structures, adjusting the packing of the head and/or tail groups, and by changing the micelle radius, in the case of a large hydrophobic PRM. We find that relatively hydrophilic PRMs with log P OW 4, are isolated deep inside the micelle, separating from the tails and swelling the radius of the micelle, leading to shorter micelles and much lower viscosities, leading eventually to swollen-droplet micelles.

Structural and phase transition changes of sodium dodecyl sulfate micellar solution in alcohols probed by small-angle neutron scattering (SANS)

Energy Technology Data Exchange (ETDEWEB)

Putra, Edy Giri Rachman [Neutron Scattering Laboratory, National Nuclear Energy Agency of Indonesia (BATAN), Gedung 40 BATAN, Kawasan Puspiptek Serpong, Tangerang 15314 (Indonesia); Patriati, Arum [Neutron Scattering Laboratory, National Nuclear Energy Agency of Indonesia (BATAN), Gedung 40 BATAN, Kawasan Puspiptek Serpong, Tangerang 15314 (Indonesia); Department of Chemistry, Faculty of Mathematics and Natural Sciences, University of Gadjah Mada, Bulaksumur, Yogyakarta 55281, Indonesia giri@batan.go.id (Indonesia)

2015-04-16

Small-angle neutron scattering (SANS) measurements on 0.3M sodium dodecyl sulfate (SDS) micellar solutions have been performed in the presence of n-alcohols, from ethanol to decanol at different alcohol concentrations, 2–10 wt%. The ellipsoid micellar structure which occurred in the 0.3M SDS in aqueous solution with the size range of 30–50 Å has different behavior at various hydrocarbon chain length and concentration of alcohols. At low concentration and short chain-length of alcohols, such as ethanol, propanol, and butanol, the size of micelles reduced and had a spherical-like structure. The opposite effect occurred as medium to long chain alcohols, such as hexanol, octanol and decanol was added into the 0.3M SDS micellar solutions. The micelles structure changed to be more elongated in major axis and then crossed the critical phase transition from micellar solution into liquid crystal phase as lamellar structure emerged by further addition of alcohols. The inter-lamellar distances were also depending on the hydrocarbon chain length and concentration of alcohols. In the meantime, the persistent micellar structures occurred in addition of medium chain of n-alcohol, pentanol at all concentrations.

Structural and phase transition changes of sodium dodecyl sulfate micellar solution in alcohols probed by small-angle neutron scattering (SANS)

International Nuclear Information System (INIS)

Putra, Edy Giri Rachman; Patriati, Arum

2015-01-01

Small-angle neutron scattering (SANS) measurements on 0.3M sodium dodecyl sulfate (SDS) micellar solutions have been performed in the presence of n-alcohols, from ethanol to decanol at different alcohol concentrations, 2–10 wt%. The ellipsoid micellar structure which occurred in the 0.3M SDS in aqueous solution with the size range of 30–50 Å has different behavior at various hydrocarbon chain length and concentration of alcohols. At low concentration and short chain-length of alcohols, such as ethanol, propanol, and butanol, the size of micelles reduced and had a spherical-like structure. The opposite effect occurred as medium to long chain alcohols, such as hexanol, octanol and decanol was added into the 0.3M SDS micellar solutions. The micelles structure changed to be more elongated in major axis and then crossed the critical phase transition from micellar solution into liquid crystal phase as lamellar structure emerged by further addition of alcohols. The inter-lamellar distances were also depending on the hydrocarbon chain length and concentration of alcohols. In the meantime, the persistent micellar structures occurred in addition of medium chain of n-alcohol, pentanol at all concentrations

Evaluation of new polymers for enhanced oil recovery; Avaliacao de novos polimeros para recuperacao aumentada de petroleo

Energy Technology Data Exchange (ETDEWEB)

Maia, Ana M.S.; Chagas, Emanuel F.; Costa, Marta; Garcia, Rosangela B. [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

2004-07-01

The main polymers used nowadays for enhanced oil recovery, partially hydrolysed polyacrylamides and xanthan gum, show some limitations, such as low tolerance to salt presence and biological degradation. Therefore, it is necessary the improvement of the polymeric properties. With this goal, a new class of polymers, named 'water-soluble polymers hydrophobically modified' or simply 'amphiphilic polymers', has been developed. In this work, it was obtained a water-soluble acrylamide polymer hydrophobically modified with N,N-dihexyl acrylamide, using the micellar copolymerization technique. After the structural and rheological characterization of the copolymer, its performance in porous medium was evaluated through core flood tests in Botucatu sandstone. In the presence of sodium chloride, the amphiphilic copolymer presented a great increase of viscosity, besides values of resistance factor and of residual resistance factor higher than for the commercial polyacrylamide. This behavior can favor the oil recovery, mainly in high salinity and permeability reservoirs, by improving the water flooding sweep efficiency. (author)

Strip waves in vibrated shear-thickening wormlike micellar solutions

Science.gov (United States)

Epstein, T.; Deegan, R. D.

2010-06-01

We present an instability in vertically vibrated dilute wormlike micellar solutions. Above a critical driving acceleration the fluid forms elongated solitary domains of high amplitude waves. We model this instability using a Mathieu equation modified to account for the non-Newtonian character of the fluid. We find that our model successfully reproduces the observed transitions.

Amplification of Chirality through Self-Replication of Micellar Aggregates in Water

KAUST Repository

Bukhriakov, Konstantin; Almahdali, Sarah; Rodionov, Valentin

2015-01-01

We describe a system in which the self-replication of micellar aggregates results in a spontaneous amplification of chirality in the reaction products. In this system, amphiphiles are synthesized from two "clickable" fragments: a water-soluble "head

Transferrin receptor-targeted pH-sensitive micellar system for diminution of drug resistance and targetable delivery in multidrug-resistant breast cancer

Directory of Open Access Journals (Sweden)

Gao W

2017-02-01

Full Text Available Wei Gao,1 Guihua Ye,1 Xiaochuan Duan,1 Xiaoying Yang,1 Victor C Yang1,2 1Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics (Theranostics, School of Pharmacy, Tianjin Medical University, Tianjin, People’s Republic of China; 2Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, Ann Arbor, MI, USA Abstract: The emergence of drug resistance is partially associated with overproduction of transferrin receptor (TfR. To overcome multidrug resistance (MDR and achieve tumor target delivery, we designed a novel biodegradable pH-sensitive micellar system modified with HAIYPRH, a TfR ligand (7pep. First, the polymers poly(l-histidine-coupled polyethylene glycol-2000 (PHIS-PEG2000 and 7pep-modified 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-polyethylene glycol-2000 (7pep-DSPE-PEG2000 were synthesized, and the mixed micelles were prepared by blending of PHIS-PEG2000 and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-polyethylene glycol-2000 (DSPE-PEG2000 or 7pep-DSPE-PEG2000 (7-pep HD micelles. The micelles exhibited good size uniformity, high encapsulation efficiency, and a low critical micelle concentration. By changing the polymer ratio in the micellar formulation, the pH response range was specially tailored to pH ~6.0. When loaded with antitumor drug doxorubicin (DOX, the micelle showed an acid pH-triggering drug release profile. The cellular uptake and cytotoxicity study demonstrated that 7-pep HD micelles could significantly enhance the intracellular level and antitumor efficacy of DOX in multidrug-resistant cells (MCF-7/Adr, which attributed to the synergistic effect of poly(l-histidine-triggered endolysosom escape and TfR-mediated endocytosis. Most importantly, the in vivo imaging study confirmed the targetability of 7-pep HD micelles to MDR tumor. These findings indicated that 7-pep HD micelles would be a promising drug delivery system in the treatment of drug

Transepithelial Transport of Curcumin in Caco-2 Cells Is significantly Enhanced by Micellar Solubilisation.

Science.gov (United States)

Frank, Jan; Schiborr, Christina; Kocher, Alexa; Meins, Jürgen; Behnam, Dariush; Schubert-Zsilavecz, Manfred; Abdel-Tawab, Mona

2017-03-01

Curcumin, the active constituent of Curcuma longa L. (family Zingiberaceae), has gained increasing interest because of its anti-cancer, anti-inflammatory, anti-diabetic, and anti-rheumatic properties associated with good tolerability and safety up to very high doses of 12 g. Nanoscaled micellar formulations on the base of Tween 80 represent a promising strategy to overcome its low oral bioavailability. We therefore aimed to investigate the uptake and transepithelial transport of native curcumin (CUR) vs. a nanoscaled micellar formulation (Sol-CUR) in a Caco-2 cell model. Sol-CUR afforded a higher flux than CUR (39.23 vs. 4.98 μg min -1  cm -2 , respectively). This resulted in a higher P app value of 2.11 × 10 -6  cm/s for Sol-CUR compared to a P app value of 0.56 × 10 -6  cm/s for CUR. Accordingly a nearly 9.5 fold higher amount of curcumin was detected on the basolateral side at the end of the transport experiments after 180 min with Sol-CUR compared to CUR. The determined 3.8-fold improvement in the permeability of curcumin is in agreement with an up to 185-fold increase in the AUC of curcumin observed in humans following the oral administration of the nanoscaled micellar formulation compared to native curcumin. The present study demonstrates that the enhanced oral bioavailability of micellar curcumin formulations is likely a result of enhanced absorption into and increased transport through small intestinal epithelial cells.

Micellar enhanced spectrofluorimetric methods: application to the determination of pyrene

Energy Technology Data Exchange (ETDEWEB)

Singh, H.; Hinze, W.L.

1982-01-01

The effects of cationic hexadecyltrimethylammonium chloride (CTAC), nonionic polyoxyethylene(9.5)p-1,1,3,3-tetramethylbutylphenol, Triton X-100 (TX-100), and anionic sodium dodecylsulfate (NaLS) surfactant micelles upon the spectrofluorimetric determination of pyrene is described. It was found that the intensity of the pyrene fluorescence is enhanced from 3 to 16 times in the presence of the micellar systems. Possible reasons for this micellar induced enhanced fluorescence are discussed. The spectral parameters, fluorescence lifetimes, quantum yields, lower detection limits, and analytical figures of merit for pyrene in CTAC, NaLS, TX-100, ethanol, and water are compared. The detection limit of pyrene in the presence of micelles (approx. 1.0 x 10/sup -10/ M) is about an order of magnitude lower than that possible in alcohol alone. A brief discussion on the predicted general applicability of this new technique in fluorimetric analysis is also given. 4 figures, 2 tables.

Unlocking Chain Exchange in Highly Amphiphilic Block Polymer Micellar Systems: Influence of Agitation.

Science.gov (United States)

Murphy, Ryan P; Kelley, Elizabeth G; Rogers, Simon A; Sullivan, Millicent O; Epps, Thomas H

2014-11-18

Chain exchange between block polymer micelles in highly selective solvents, such as water, is well-known to be arrested under quiescent conditions, yet this work demonstrates that simple agitation methods can induce rapid chain exchange in these solvents. Aqueous solutions containing either pure poly(butadiene- b -ethylene oxide) or pure poly(butadiene- b -ethylene oxide- d 4 ) micelles were combined and then subjected to agitation by vortex mixing, concentric cylinder Couette flow, or nitrogen gas sparging. Subsequently, the extent of chain exchange between micelles was quantified using small angle neutron scattering. Rapid vortex mixing induced chain exchange within minutes, as evidenced by a monotonic decrease in scattered intensity, whereas Couette flow and sparging did not lead to measurable chain exchange over the examined time scale of hours. The linear kinetics with respect to agitation time suggested a surface-limited exchange process at the air-water interface. These findings demonstrate the strong influence of processing conditions on block polymer solution assemblies.

A kinetic study of 1,3-dipolar cycloadditions in micellar media

NARCIS (Netherlands)

Rispens, T; Engberts, JBFN

2003-01-01

The kinetics of the 1,3-dipolar cycloadditions (DC) of benzonitrile oxide with a series of N-substituted maleimides in micellar media have been investigated. Surfactants studied include anionic sodium dodecyl sulfate, cationic cetyltrimethylammonium bromide, and a series of nonionic alkyl

phenylalanine and l-tyrosine as chiral micellar media for the cat

African Journals Online (AJOL)

potential chiral micellar catalysts for the Diels-Alder reaction between methyl acrylate and .... hydrophobic effects, electrostatic interactions and the accompanying medium effects. In the case .... liquids as effective organocatalysts for Diels-Alder reaction. Green Chem. 2014, 16 .... Colloids and Surfaces A: Physicochem.

Retention of bile salts in micellar electrokinetic chromatography: relation of capacity factor to octanol-water partition coefficient and critical micellar concentration.

Science.gov (United States)

Lucangioli, S E; Carducci, C N; Tripodi, V P; Kenndler, E

2001-12-25

The capacity factors of 16 anionic cholates (from six bile salts, including their glyco- and tauro-conjugates) were determined in a micellar electrokinetic chromatography (MEKC) system consisting of buffer, pH 7.5 (phosphate-boric acid; 20 mmol/l) with 50 mmol/l sodium dodecyl sulfate (SDS) as micelle former and 10% acetonitrile as organic modifier. The capacity factors of the fully dissociated, negatively charged analytes (ranging between 0.2 and 60) were calculated from their mobilities, with a reference background electrolyte (BGE) without SDS representing "free" solution. For comparison, the capacity factors were derived for a second reference BGE where the SDS concentration (5 mmol/l) is close to the critical micellar concentration (CMC). The capacity factors are compared with the logarithm of the octanol-water partition coefficient, log Pow, as measure for lipophilicity. Clear disagreement between these two parameters is found especially for epimeric cholates with the hydroxy group in position 7. In contrast, fair relation between the capacity factor of the analytes and their CMC is observed both depending strongly on the orientation of the OH groups, and tauro-conjugation as well. In this respect the retention behaviour of the bile salts in MEKC seems to reflect their role as detergents in living systems, and might serve as model parameter beyond lipophilicity.

Modulated photophysics of 2-anthracene sulphonate in micellar assembly

International Nuclear Information System (INIS)

Rana, Dipak Kumar; Sarkar, Arindam; Dhar, Sayaree; Mandal, Tapas Kumar; Bhattacharya, Subhash Chandra

2010-01-01

The association of a non-ionic surfactant of polyoxyethylene-p-(1,1,3,3-tetramethylbutyl)phenyl ether (Triton X) series with 2-AS in aqueous solution has been studied by means of steady-state, time-resolved fluorescence and fluorescence anisotropy techniques. The effect of the hydrophobic chain length on the structural dynamism of the fluorophore has been reported. Experimental results demonstrate that the equilibrium of this dynamism is sensitive to the environment. The association constant of the probe molecule with the non-ionic micelles of Triton X (TX), location of the probe in the micellar environment, have been determined from the change in emission characteristics of the probe as a function of surfactant concentration. The rate constant of quenching and mode of quenching of probe in micellar media have been ascertained. Quantitative estimates of the micropolarity at the binding sites of the probe molecule have been determined. Some of the environment-dependent relevant fluorescence parameters, fluorescence anisotropy (r), have been monitored for exploring the imposed motional restriction of the microenvironment around the probe. An attempt has been made to correlate the steady-state results with time resolved study.

αvβ3 integrin-targeted micellar mertansine prodrug effectively inhibits triple-negative breast cancer in vivo

Directory of Open Access Journals (Sweden)

Zhong P

2017-10-01

Full Text Available Ping Zhong,1,2 Xiaolei Gu,1,2 Ru Cheng,1,2 Chao Deng,1,2 Fenghua Meng,1,2 Zhiyuan Zhong1,2 1Biomedical Polymers Laboratory, 2Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, China Abstract: Antibody-mertansine (DM1 conjugates (AMCs are among the very few active targeting therapeutics that are approved or clinically investigated for treating various cancers including metastatic breast cancer. However, none of the AMCs are effective for the treatment of triple-negative breast cancers (TNBCs. Here, we show that cRGD-decorated, redox-activatable micellar mertansine prodrug (cRGD-MMP can effectively target and deliver DM1 to αvβ3 integrin overexpressing MDA-MB-231 TNBC xenografts in nude mice, resulting in potent tumor growth inhibition. 3-(4,5-Dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT assays showed that cRGD-MMP had obvious targetability to MDA-MB-231 cells with a low half-maximal inhibitory concentration (IC50 of 0.18 µM, which was close to that of free DM1 and 2.2-fold lower than that of micellar mertansine prodrug (MMP; nontargeting control. The confocal microscopy studies demonstrated that cRGD-MMP mediated a clearly more efficient cellular uptake and intracellular release of doxorubicin (used as a fluorescent anticancer drug model in MDA-MB-231 cells. Notably, cRGD-MMP loaded with 1,1'-dioctadecyltetramethyl indotricarbocyanine iodide (DiR; a hydrophobic near-infrared dye was shown to quickly accumulate in the MDA-MB-231 tumor with strong DiR fluorescence from 2 to 24 h post injection. MMP loaded with DiR could also accumulate in the tumor, although significantly less than cRGD-MMP. The biodistribution studies revealed a high DM1 accumulation of 8.1%ID/g in the tumor for cRGD-MMP at 12 h post injection. The therapeutic results demonstrated that cRGD-MMP effectively suppressed MDA-MB-231 tumor growth at

Evolution of ZnS Nanoparticles via Facile CTAB Aqueous Micellar Solution Route: A Study on Controlling Parameters

Directory of Open Access Journals (Sweden)

Gradzielski Michael

2008-01-01

Full Text Available Abstract Synthesis of semiconductor nanoparticles with new photophysical properties is an area of special interest. Here, we report synthesis of ZnS nanoparticles in aqueous micellar solution of Cetyltrimethylammonium bromide (CTAB. The size of ZnS nanodispersions in aqueous micellar solution has been calculated using UV-vis spectroscopy, XRD, SAXS, and TEM measurements. The nanoparticles are found to be polydispersed in the size range 6–15 nm. Surface passivation by surfactant molecules has been studied using FTIR and fluorescence spectroscopy. The nanoparticles have been better stabilized using CTAB concentration above 1 mM. Furthermore, room temperature absorption and fluorescence emission of powdered ZnS nanoparticles after redispersion in water have also been investigated and compared with that in aqueous micellar solution. Time-dependent absorption behavior reveals that the formation of ZnS nanoparticles depends on CTAB concentration and was complete within 25 min.

Preparation of a Mini-Library of Thermo-Responsive Star (NVCL/NVP-VAc Polymers with Tailored Properties Using a Hexafunctional Xanthate RAFT Agent

Directory of Open Access Journals (Sweden)

Norma Aidé Cortez-Lemus

2017-12-01

Full Text Available A mini-library of star-shaped thermoresponsive polymers having six arms was prepared using a hexafunctional xanthate by reversible addition–fragmentation chain transfer (RAFT polymerization. Star polymers with homopolymeric arms of poly(N-vinylcaprolactam (PNVCL, copolymeric arms of poly(N-vinylcaprolactam-co-N-vinylpyrrolidone (PNVCL-co-PNVP and also arms of block copolymers of PNVCL-b-PVAc, (PNVCL-co-PNVP-b-PVAc, and combinations of them changing the order of the block was achieved exploiting the R-RAFT synthetic methodology (or R-group approach, wherein the thiocarbonyl group is transferred to the polymeric chain end. Taking advantage of the RAFT benefits, the molecular weight of the star polymers was controlled (Mn = 11,880–153,400 g/mol to yield star polymers of different sizes and lower critical solution temperature (LCST values. Removing the xanthate group of the star polymers allowed for the introduction of specific functional groups at the ends of the star arms and resulted in an increase of the LCST values. Star PNVCL-b-PVAc diblock copolymers with PVAc contents of 5–26 mol % were prepared; the hydrophobic segment (PVAc is located at the end of the star arms. Interestingly, when the PVAc content was 5–7 mol %, the hydrodynamic diameter (Dh value of the aggregates formed in water was almost the same sa the Dh of the corresponding PNVCL star homopolymers. It is proposed that these star block copolymers self-assemble into single flowerlike micelles, showing great stability in aqueous solution. Star block copolymers with the PVAc hydrophobic block in the core of the star, such as PVAc-b-(PNVCL-co-PNVP, form micellar aggregates in aqueous solution with Dh values in the range from ~115 to 245 nm while maintaining a thermoresponsive behavior. Micellar aggregates of selected star polymers were used to encapsulate methotrexate (MTX showing their potential in the temperature controlled release of this antineoplasic drug. The importance

Polymeric micellar pH-sensitive drug delivery system for doxorubicin.

Science.gov (United States)

Hrubý, Martin; Konák, Cestmír; Ulbrich, Karel

2005-03-02

A novel polymeric micellar pH-sensitive system for delivery of doxorubicin (DOX) is described. Polymeric micelles were prepared by self-assembly of amphiphilic diblock copolymers in aqueous solutions. The copolymers consist of a biocompatible hydrophilic poly(ethylene oxide) (PEO) block and a hydrophobic block containing covalently bound anthracycline antibiotic DOX. The starting block copolymers poly(ethylene oxide)-block-poly(allyl glycidyl ether) (PEO-PAGE) with a very narrow molecular weight distribution (Mw/Mn ca. 1.05) were prepared by anionic ring opening polymerization using sodium salt of poly(ethylene oxide) monomethyl ether as macroinitiator and allyl glycidyl ether as functional monomer. The copolymers were covalently modified via reactive double bonds by the addition of methyl sulfanylacetate. The resulting ester subsequently reacted with hydrazine hydrate yielding polymer hydrazide. The hydrazide was coupled with DOX yielding pH-sensitive hydrazone bonds between the drug and carrier. The resulting conjugate containing ca. 3 wt.% DOX forms micelles with Rh(a)=104 nm in phosphate-buffered saline. After incubation in buffers at 37 degrees C DOX was released faster at pH 5.0 (close to pH in endosomes; 43% DOX released within 24 h) than at pH 7.4 (pH of blood plasma; 16% DOX released within 24 h). Cleavage of hydrazone bonds between DOX and carrier continues even after plateau in the DOX release from micelles incubated in aqueous solutions is reached.

Effect of tartarate and citrate based food additives on the micellar properties of sodium dodecylsulfate for prospective use as food emulsifier.

Science.gov (United States)

Banipal, Tarlok S; Kaur, Harjinder; Kaur, Amanpreet; Banipal, Parampaul K

2016-01-01

Citrate and tartarate based food preservatives can be used to enhance the emulsifying properties of sodium dodecylsulfate (SDS) based micellar system and thus making it appropriate for food applications. Exploration of interactions between the two species is the key constraint for execution of such ideas. In this work various micellar and thermodynamic parameters of SDS like critical micellar concentration (CMC), standard Gibbs free energy of micellization (ΔG(0)mic.) etc. have been calculated in different concentrations of disodium tartarate (DST) and trisodium citrate (TSC) in the temperature range (288.15-318.15)K from the conductivity and surface tension measurements. The parameters obtained from these studies reveal the competitive nature of both the additives with SDS for available positions at the air/water interface. TSC is found to be more effective additive in order to make SDS micellar system better for its potential applications as food emulsifier. Copyright © 2015 Elsevier Ltd. All rights reserved.

Determination of patulin in commercial apple juice by micellar electrokinetic chromatography.

Science.gov (United States)

Murillo, M; González-Peñas, E; Amézqueta, S

2008-01-01

A novel and validated micellar electrokinetic capillary chromatography (MEKC) method using ultraviolet detection (UV) has been applied to the quantitative analysis of patulin (PAT) in commercial apple juice. Patulin was extracted from samples with an ethylacetate solution. The micellar electrokinetic capillary chromatography (MECK) parameters studied for method optimization were buffer composition, voltage, temperature, and a separation between PAT and 5-hydroxymethylfurfural (HMF) (main interference in apple juice PAT analysis) peaks until reaching baseline. The method passes a series of validation tests including selectivity, linearity, limit of detection and quantification (0.7 and 2.5 microgL(-1), respectively), precision (within and between-day variability) and recovery (80.2% RSD=4%), accuracy, and robustness. This method was successfully applied to the measurement of 20 apple juice samples obtained from different supermarkets. One hundred percent of the samples were contaminated with a level greater than the limit of detection, with mean and median values of 41.3 and 35.7 microgL(-1), respectively.

Thermodynamic analysis of unimer-micelle and sphere-to-rod micellar transitions of aqueous solutions of sodium dodecylbenzenesulfonate

International Nuclear Information System (INIS)

Valente, Artur J.M.; López Cascales, J.J.; Fernández Romero, Antonio J.

2014-01-01

Highlights: • Unimer-micelle and sphere-to-rod micellar transitions were observed to sodium dodecylbenzenesulfonate in aqueous solutions. • Two micellar transitions were seen by electrical conductivity and surface tension. • An anomalous ΔS 0 and ΔH 0 increase with T was found for the second critical transition. • More stable aggregates are evidenced for spherical micelles than for the other shapes. - Abstract: Temperature dependence of specific conductivity of sodium dodecylbenzenesulfonate (NaDBS) aqueous solutions was analyzed. Two breaks on the plot appeared for all temperature, which suggest two micellar transitions. This has been corroborated by surface tension measurements. The first transition concentration occurs at the critical micelle concentration (CMC), whilst the second critical concentration (so-called transition micellar concentration, TMC) is due to a sphere-to-rod micelles transition. The dependence of CMC and TMC on the temperature allows the computation of the corresponding thermodynamic functions: Gibbs free energy, enthalpy and entropy changes. For the CMC, enthalpy and entropy increments were found that decrease with the temperature values. However, an anomalous behavior was obtained for the TMC, where both ΔS 0 and ΔH 0 values raised with the temperature increase. However, for both transitions, an (enthalpy + entropy) compensation is observed. These results will be compared with similar systems reported in the literature

Probing the amphiphile micellar to hexagonal phase transition using Positron Annihilation Lifetime Spectroscopy.

Science.gov (United States)

Dong, Aurelia W; Fong, Celesta; Hill, Anita J; Boyd, Ben J; Drummond, Calum J

2013-07-15

Positron Annihilation Lifetime Spectroscopy (PALS) has been utilised only sparingly for structural characterisation in self assembled materials. Inconsistencies in approaches to experimental configuration and data analysis between studies has complicated comparisons between studies, meaning that the technique has not provided a cohesive data set across the study of different self assembled systems that advance the technique towards an important tool in soft matter research. In the current work a systematic study was conducted using ionic and non-ionic micellar systems with increasing surfactant concentration to probe positron behaviour on changes between micellar phase structures, and data analysed using contemporary approaches to fit four component spectra. A characteristic orthopositronium lifetime (in the organic regions) of 3.5±0.2 ns was obtained for the hexagonal phase for surfactants with C12 alkyl chains. Chemical quenching of the positron species was also observed for systems with ionic amphiphiles. The application of PALS has also highlighted an inconsistency in the published phase diagram for the octa(ethylene oxide) monododecyl ether (C12EO8) system. These results provide new insight into how the physical properties of micellar systems can be related to PALS parameters and means that the PALS technique can be applied to other more complex self-assembled amphiphile systems. Copyright © 2013 Elsevier Inc. All rights reserved.

phenylalanine and l-tyrosine as chiral micellar media for the cat

African Journals Online (AJOL)

polar solvents [15-18]. Hence, surfactants offer the possibility for organic reactions to occur in aqueous media, and from the viewpoint of green chemistry, water is safer, harmless and environmentally benign [19]. However, there has been limited work on the use of chiral micellar media to catalyze Diels-. Alder reactions.

Phase behavior and micellar properties of carboxylic acid end group modified pluronic surfactants

NARCIS (Netherlands)

Custers, J.P.A.; Broeke, van den L.J.P.; Keurentjes, J.T.F.

2007-01-01

The micellar behavior of three different carboxylic acid end standing (CAE) surfactants has been characterized using conductometry, differential scanning calorimetry, isothermal titration calorimetry, and dynamic light scattering. The CAE surfactants are modified high molecular weight Pluronic

Structural study of the AOT reverse micellar system. Influence of attractive interactions induced by the solubilisation of native and modified proteins

International Nuclear Information System (INIS)

Cassin, Guillaume

1994-01-01

This research thesis reports the study of the influence of intra-micellar attractions on the thermodynamic behaviour of reverse micellar systems, as well as of the effects induced by the solubilisation of natives or modified proteins. The author proposes a model to explain the decrease of attractions between droplets when the volume fraction occupied by reverse micelles increases. This model which highlights the importance of depletion forces between reverse micelles, allows the building up of a theoretical relationship between the bonding parameter and the volume fraction of reverse micelles. In order to understand the appearance of an attractive term related to the solubilisation of native cytochrome-c in these systems, this protein has been chemically modified. The author highlights the role of the charge born by a micellar probe on the thermodynamic behaviour of micro-emulsions. Then, the author applies the model of dimerizing adhesive spheres to reverse micellar systems containing native cytochrome-c. He shows that theoretical predictions of this model are in agreement with obtained experimental results [fr

Computer Color Matching and Levelness of PEG-Based Reverse Micellar Decamethyl cyclopentasiloxane (D5 Solvent-Assisted Reactive Dyeing on Cotton Fiber

Directory of Open Access Journals (Sweden)

Alan Y. L. Tang

2017-07-01

Full Text Available The color matching and levelness of cotton fabrics dyed with reactive dye, in a non-aqueous environmentally-friendly medium of decamethylcyclopentasiloxane (D5, was investigated using the non-ionic surfactant reverse-micellar approach comprised of poly(ethylene glycol-based surfactant. The calibration dyeing databases for both conventional water-based dyeing and D5-assisted reverse micellar dyeing were established, along with the dyeing of standard samples with predetermined concentrations. Computer color matching (CCM was conducted by using different color difference formulae for both dyeing methods. Experimental results reveal that the measured concentrations were nearly the same as the expected concentrations for both methods. This indicates that the D5-assisted non-ionic reverse micellar dyeing approach can achieve color matching as good as the conventional dyeing system. The levelness of the dyed samples was measured according to the relative unlevelness indices (RUI, and the results reveal that the samples dyed by the D5 reverse micellar dyeing system can achieve good to excellent levelness comparable to that of the conventional dyeing system.

Intermolecular electron transfer between coumarin dyes and aromatic amines in Triton-X-100 micellar solutions: Evidence for Marcus inverted region

Science.gov (United States)

Kumbhakar, Manoj; Nath, Sukhendu; Mukherjee, Tulsi; Pal, Haridas

2004-02-01

Photoinduced electron transfer (ET) between coumarin dyes and aromatic amines has been investigated in Triton-X-100 micellar solutions and the results have been compared with those observed earlier in homogeneous medium. Significant static quenching of the coumarin fluorescence due to the presence of high concentration of amines around the coumarin fluorophore in the micelles has been observed in steady-state fluorescence studies. Time-resolved studies with nanosecond resolutions mostly show the dynamic part of the quenching for the excited coumarin dyes by the amine quenchers. A correlation of the quenching rate constants, estimated from the time-resolved measurements, with the free energy changes (ΔG0) of the ET reactions shows the typical bell shaped curve as predicted by Marcus outer-sphere ET theory. The inversion in the ET rates for the present systems occurs at an exergonicity (-ΔG0) of ~0.7-0.8 eV, which is unusually low considering the polarity of the Palisade layer of the micelles where the reactants reside. Present results have been rationalized on the basis of the two dimensional ET model assuming that the solvent relaxation in micellar media is much slower than the rate of the ET process. Detailed analysis of the experimental data shows that the diffusional model of the bimolecular quenching kinetics is not applicable for the ET reactions in the micellar solutions. In the present systems, the reactions can be better visualized as equivalent to intramolecular electron transfer processes, with statistical distribution of the donors and acceptors in the micelles. A low electron coupling (Vel) parameter is estimated from the correlation of the experimentally observed and the theoretically calculated ET rates, which indicates that the average donor-acceptor separation in the micellar ET reactions is substantially larger than for the donor-acceptor contact distance. Comparison of the Vel values in the micellar solution and in the donor-acceptor close

Microstructural evolution of a model, shear-banding micellar solution during shear startup and cessation.

Science.gov (United States)

López-Barrón, Carlos R; Gurnon, A Kate; Eberle, Aaron P R; Porcar, Lionel; Wagner, Norman J

2014-04-01

We present direct measurements of the evolution of the segmental-level microstructure of a stable shear-banding polymerlike micelle solution during flow startup and cessation in the plane of flow. These measurements provide a definitive, quantitative microstructural understanding of the stages observed during flow startup: an initial elastic response with limited alignment that yields with a large stress overshoot to a homogeneous flow with associated micellar alignment that persists for approximately three relaxation times. This transient is followed by a shear (kink) band formation with a flow-aligned low-viscosity band that exhibits shear-induced concentration fluctuations and coexists with a nearly isotropic band of homogenous, highly viscoelastic micellar solution. Stable, steady banding flow is achieved only after approximately two reptation times. Flow cessation from this shear-banded state is also found to be nontrivial, exhibiting an initial fast relaxation with only minor structural relaxation, followed by a slower relaxation of the aligned micellar fluid with the equilibrium fluid's characteristic relaxation time. These measurements resolve a controversy in the literature surrounding the mechanism of shear banding in entangled wormlike micelles and, by means of comparison to existing literature, provide further insights into the mechanisms driving shear-banding instabilities in related systems. The methods and instrumentation described should find broad use in exploring complex fluid rheology and testing microstructure-based constitutive equations.

Micellar copolymerization of poly(acrylamide-g-propylene oxide): rheological evaluation and solution characterization; Copolimerizacao micelar de poli(acrilamida-g-oxido de propileno): avaliacao reologica e caracterizacao de suas solucoes

Energy Technology Data Exchange (ETDEWEB)

Sadicoff, Bianca L.; Brandao, Edimir M.; Lucas, Elizabete F. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Macromoleculas]. E-mail: elucas@ima.ufrj.br; Amorim, Marcia C.V. [Universidade Estadual, Rio de Janeiro, RJ (Brazil). Inst. de Quimica

2001-06-01

Graft copolymers of polyacrylamide and poly(propylene oxide) were synthesized by a micellar copolymerization technique. The rheological properties of the copolymers solutions were evaluated and compared with literature data for solutions of the same copolymers, synthesized by solution polymerization. The effect of hydrophobe content, salt addition and surfactant addition on the rheological properties were also investigated. Increasing hydrophobe content resulted in higher solution viscosities in the semi-dilute regime. Upon addition of salts, the hydrophobic groups associated to minimize their exposure to water. In the semi-dilute region, higher contents of surfactant added resulted in lower reduced viscosities of the polymer solutions. The copolymers were qualitatively characterized by infra-red spectrometry. (author)

Complexation of lysozyme with sodium caseinate and micellar casein in aqueous buffered solutions

NARCIS (Netherlands)

Antonov, Y.A.; Moldenaers, P.; Cardinaels, R.M.

We present an extended structural and morphological study of the complexation of lysozyme (Lys) with sodium caseinate (SC) and micellar casein (MC) by means of turbidity measurements, phase analysis, dynamic, static and electrophoretic light scattering, bright-field and confocal laser scanning

Spectroscopic studies on the molecular interaction between salicylic acid and riboflavin (B{sub 2}) in micellar solution

Energy Technology Data Exchange (ETDEWEB)

Bhattar, S.L.; Kolekar, G.B. [Fluorescence Spectroscopy Research Laboratory, Department of Chemistry, Shivaji University, Kolhapur-416 004, Maharashtra (India); Patil, S.R., E-mail: srp_fsl@rediffmail.co [Fluorescence Spectroscopy Research Laboratory, Department of Chemistry, Shivaji University, Kolhapur-416 004, Maharashtra (India)

2010-03-15

The interaction between salicylic acid (SA) and riboflavin (RF) was studied by Fluorescence Resonance Energy Transfer (FRET) in micellar solution. The riboflavin strongly quenches the intrinsic fluorescence of SA by radiative energy transfer. The extent of energy transfer in sodium dodecyl sulphate (SDS) micellar solution of different concentration is quantified from the energy transfer efficiency data. It is seen that the energy transfer is more efficient in the micellar solution. The critical energy transfer distance (R{sub 0}) was determined from which the mean distance between SA and RF molecules was calculated. The quenching was found to fit into Stern-Volmer relation. The results on variation of Stern-Volmer constant (K{sub sv}) with quencher concentration obtained at different temperatures suggested the formation of complex between SA and RF. The association constant of complex formation was estimated and found to decrease with temperature. The values of thermodynamic parameters DELTAH, DELTAG and DELTAS at different temperatures were estimated and the results indicated that the molecular interaction between SA and RF is electrostatic in nature.

Micellar solubilization in strongly interacting binary surfactant systems. [Binary surfactant systems of: dodecyltrimethylammonium chloride + sodium dodecyl sulfate; benzyldimethyltetradecylammonium chloride + tetradecyltrimethylammonium chloride

Energy Technology Data Exchange (ETDEWEB)

Treiner, C. (Universite Pierre et Marie Curie, Paris (France)); Nortz, M.; Vaution, C. (Faculte de Pharmacie de Paris-sud, Chatenay-Malabry (France))

1990-07-01

The apparent partition coefficient P of barbituric acids between micelles and water has been determined in mixed binary surfactant solutions from solubility measurements in the whole micellar composition range. The binary systems chosen ranged from the strongly interacting system dodecyltrimethylammonium chloride + sodium dodecyl sulfate to weakly interacting systems such as benzyldimethyltetradecylammonium chloride + tetradecyltrimethyammonium chloride. In all cases studied, mixed micelle formation is unfavorable to micellar solubilization. A correlation is found between the unlike surfactants interaction energy, as measured by the regular solution parameter {beta} and the solute partition coefficient change upon surfactant mixing. By use of literature data on micellar solubilization in binary surfactant solutions, it is shown that the change of P for solutes which are solubilized by surface adsorption is generally governed by the sign and amplitude of the interaction parameter {beta}.

Mixtures of lecithin and bile salt can form highly viscous wormlike micellar solutions in water.

Science.gov (United States)

Cheng, Chih-Yang; Oh, Hyuntaek; Wang, Ting-Yu; Raghavan, Srinivasa R; Tung, Shih-Huang

2014-09-02

The self-assembly of biological surfactants in water is an important topic for study because of its relevance to physiological processes. Two common types of biosurfactants are lecithin (phosphatidylcholine) and bile salts, which are both present in bile and involved in digestion. Previous studies on lecithin-bile salt mixtures have reported the formation of short, rodlike micelles. Here, we show that lecithin-bile salt micelles can be further induced to grow into long, flexible wormlike structures. The formation of long worms and their resultant entanglement into transient networks is reflected in the rheology: the fluids become viscoelastic and exhibit Maxwellian behavior, and their zero-shear viscosity can be up to a 1000-fold higher than that of water. The presence of worms is further confirmed by data from small-angle neutron and X-ray scattering and from cryo-transmission electron microscopy (cryo-TEM). We find that micellar growth peaks at a specific molar ratio (near equimolar) of bile salt:lecithin, which suggests a strong binding interaction between the two species. In addition, micellar growth also requires a sufficient concentration of background electrolyte such as NaCl or sodium citrate that serves to screen the electrostatic repulsion of the amphiphiles and to "salt out" the amphiphiles. We postulate a mechanism based on changes in the molecular geometry caused by bile salts and electrolytes to explain the micellar growth.

Can neutral analytes be concentrated by transient isotachophoresis in micellar electrokinetic chromatography and how much?

Science.gov (United States)

Matczuk, Magdalena; Foteeva, Lidia S; Jarosz, Maciej; Galanski, Markus; Keppler, Bernhard K; Hirokawa, Takeshi; Timerbaev, Andrei R

2014-06-06

Transient isotachophoresis (tITP) is a versatile sample preconcentration technique that uses ITP to focus electrically charged analytes at the initial stage of CE analysis. However, according to the ruling principle of tITP, uncharged analytes are beyond its capacity while being separated and detected by micellar electrokinetic chromatography (MEKC). On the other hand, when these are charged micelles that undergo the tITP focusing, one can anticipate the concentration effect, resulting from the formation of transient micellar stack at moving sample/background electrolyte (BGE) boundary, which increasingly accumulates the analytes. This work expands the enrichment potential of tITP for MEKC by demonstrating the quantitative analysis of uncharged metal-based drugs from highly saline samples and introducing to the BGE solution anionic surfactants and buffer (terminating) co-ions of different mobility and concentration to optimize performance. Metallodrugs of assorted lipophilicity were chosen so as to explore whether their varying affinity toward micelles plays the role. In addition to altering the sample and BGE composition, optimization of the detection capability was achieved due to fine-tuning operational variables such as sample volume, separation voltage and pressure, etc. The results of optimization trials shed light on the mechanism of micellar tITP and render effective determination of selected drugs in human urine, with practical limits of detection using conventional UV detector. Copyright © 2014 Elsevier B.V. All rights reserved.

Effect of the hydrophilic block length on the surface-active and micellar thermodynamic properties of oxyethylene-oxybutylene diblock copolymers in aqueous solution

International Nuclear Information System (INIS)

Khan, A.; Usman, M.; Siddiq, M.; Fatima, G.; Harrison, W.

2009-01-01

The effect of hydrophilic block length on the surface and micellar thermodynamic properties of aqueous solution of E/sub 40/B/sub 8/, E/sub 80/B/sub 8/ and E/sub 120/B/sub 8/ diblock copolymers, were studied by surface tension measurements over a wide concentration and temperature range; where E stands for an oxyethylene unit and B for an oxybutylene unit. Like conventional surfactants, two breaks (change in the slope) were observed in the surface tension vs logarithm of concentration curve for all the three copolymers. Surface tension measurements were used to estimate surface excess concentrations (r m), area per molecule at air/water interface a and thermodynamic parameters for all adsorption of the pre-micellar region in the temperature range 20 to 50 degree C. Likewise the critical micelle concentration, CMC and thermodynamic parameters for micellization were also calculated for the post-micellar solutions at all temperatures. For comparison the thermodynamic parameters of adsorption and micellization are discussed in detail. The impact of varying E-block length and temperature on all calculated parameters are also discussed. This study shows the importance of hydrophobic-hydrophilic-balance (HHB) of copolymers on various surface and micellar properties. (author)

Influence of molar mass, dispersity, and type and location of hydrophobic side chain moieties on the critical micellar concentration and stability of amphiphilic HPMA-based polymer drug carriers

Czech Academy of Sciences Publication Activity Database

Filippov, Sergey K.; Vishnevetskaya, N. S.; Niebuur, B.-J.; Koziolová, Eva; Lomkova, Ekaterina A.; Chytil, Petr; Etrych, Tomáš; Papadakis, C. M.

2017-01-01

Roč. 295, č. 8 (2017), s. 1313-1325 ISSN 0303-402X R&D Projects: GA MZd(CZ) NV16-28600A; GA ČR(CZ) GC15-10527J Institutional support: RVO:61389013 Keywords : drug delivery * HPMA copolymers * fluorescence correlation spectroscopy Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 1.723, year: 2016

Interactions between 9,10-anthraquinone and aromatic amines in homogeneous and micellar media: A laser flash photolysis and magnetic field effect study

International Nuclear Information System (INIS)

Chowdhury, Adity; Basu, Samita

2006-01-01

The interactions between 9,10-anthraquinone (AQ) and different aromatic amines, N,N-dimethylaniline and 4,4'-bis (dimethylamino) diphenylmethane (DMDPM), have been studied using absorption, steady-state fluorescence, and laser flash photolysis techniques in organic homogeneous and heterogeneous micellar media. In polar organic homogeneous medium, electron transfer (ET) occurs from amines to excited AQ. In micellar medium, similar intermolecular ET is observed. However, in latter medium, ET predominates over hydrogen abstraction from micelles by excited AQ itself. The occurrence of ET has been further supported by the application of an external magnetic field during laser flash photolysis experiments, which modulates the yield of radical ion pairs formed through ET. Another novel feature, which has also been discussed here, is the abnormal behavior of DMDPM in micellar medium pertaining to energy transfer

The Mobile Phase Motion in Ascending Micellar Thin-Layer Chromatography with Normal-Phase Plates

NARCIS (Netherlands)

Boichenko, Alexander P.; Makhno, Iryna V.; Renkevich, Anton Yu.; Loginova, Lidia P.

2011-01-01

The physical chemical characteristics (surface tension and viscosity) of micellar mobile phases based on the cationic surfactant cetylpiridinium chloride and additives of alcohols (ethanol, 1-propanol, 1-butanol, 1-pentanol) have been obtained in this work. The effect of mobile phase properties on

Atmospheric pressure photoionization for enhanced compatibility in on-line micellar electrokinetic chromatography-mass spectrometry

NARCIS (Netherlands)

Mol, Roelof; De Jong, Gerhardus J.; Somsen, Govert W.

2005-01-01

Atmospheric pressure photoionization (APPI) is presented as a novel means for the combination of micellar electrokinetic chromatography (MEKC) and mass spectrometry (MS). The on-line coupling is achieved using an adapted sheath flow interface installed on an orthogonal APPI source. Acetone or

Organisation and shape of micellar solutions of block copolymers

Science.gov (United States)

Gaspard, J. P.; Creutz, S.; Bouchat, Ph.; Jérôme, R.; Cohen Stuart, M.

1997-02-01

Diblock copolymers of polymethacrylic acid sodium salt, forming the hair, and styrene derivatives have been studied in aqueous solutions by SANS and SAXS. The influence of both the chemical nature and the length of the hydrophobic bloxk on the size and shape of micelles have been investigated. The micellar core size is in agreement with the theoretical evaluation for copolymers with a short hydrophobic sequence. In contrast, in case of larger hydrophobic blocks, the measured size is incompatible with a star-like model. Various hypotheses are presented for the latter.

Clickable antifouling polymer brushes for polymer pen lithography

Czech Academy of Sciences Publication Activity Database

Bog, U.; de los Santos Pereira, Andres; Mueller, S. L.; Havenridge, S.; Parrillo, Viviana; Bruns, M.; Holmes, A. E.; Rodriguez-Emmenegger, C.; Fuchs, H.; Hirtz, M.

2017-01-01

Roč. 9, č. 13 (2017), s. 12109-12117 ISSN 1944-8244 R&D Projects: GA ČR(CZ) GJ15-09368Y Institutional support: RVO:61389013 Keywords : antifouling * biofunctional interfaces * polymer brushes Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 7.504, year: 2016

Recent Progress in Functional Micellar Carriers with Intrinsic Therapeutic Activities for Anticancer Drug Delivery.

Science.gov (United States)

Qu, Ying; Chu, BingYang; Shi, Kun; Peng, JinRong; Qian, ZhiYong

2017-12-01

Polymeric micelles have presented superior delivery properties for poorly water-soluble chemotherapeutic agents. However, it remains discouraging that there may be some additional short or long-term toxicities caused by the metabolites of high quantities of carriers. If carriers had simultaneous therapeutic effects with the drug, these issues would not be a concern. For this, carriers not only simply act as drug carriers, but also exert an intrinsic therapeutic effect as a therapeutic agent. The functional micellar carriers would be beneficial to maximize the anticancer effect, overcome the drug resistance and reduce the systemic toxicity. In this review, we aim to summarize the recent progress on the development of functional micellar carriers with intrinsic anticancer activities for the delivery of anticancer drugs. This review focuses on the design strategies, properties of carriers and the drug loading behavior. In addition, the combinational therapeutic effects between carriers and chemotherapeutic agents are also discussed.

ASP project. Dissolved oxygen issues in ASP project

Directory of Open Access Journals (Sweden)

M.Y. Bondar

2018-03-01

Full Text Available The article presents the latest results of studies about the effect of dissolved oxygen on the efficiency of the ASP flooding project implemented by Salym Petroleum Development N.V.. Pilot project on experimental injection of anionic surfactant solutions, soda and polymer into the reservoir for enhanced oil recovery (ASP project has been implemented since 2016. The stability of one of the components of the ASP polymer is strongly dependent on the presence of iron, stiffness cations and dissolved oxygen in the water. Since the polymer is used for injection at two stages of the project, which are essential and the longest, at the design stage of ASP project a whole complex of polymer protection had been established against negative factors, in particular from the influence of oxygen, which causes not only oxygen corrosion but also irreversible destruction polymer chains. In the paper, studies on the stability of polymer solutions are described, an analysis of viscosity loss with time in the presence of iron and oxygen for polymer solutions is carried out. The choice of chemical deoxygenation method for the control of dissolved oxygen is substantiated. The program of laboratory studies of the ASP project and the analytical instruments used are described. The technological scheme of the ASP process is presented, and recommendations for the implementation of the technology are given.

Micelles from lipid derivatives of water-soluble polymers as delivery systems for poorly soluble drugs.

Science.gov (United States)

Lukyanov, Anatoly N; Torchilin, Vladimir P

2004-05-07

Polymeric micelles have a whole set of unique characteristics, which make them very promising drug carriers, in particular, for poorly soluble drugs. Our review article focuses on micelles prepared from conjugates of water-soluble polymers, such as polyethylene glycol (PEG) or polyvinyl pyrrolidone (PVP), with phospholipids or long-chain fatty acids. The preparation of micelles from certain polymer-lipid conjugates and the loading of these micelles with various poorly soluble anticancer agents are discussed. The data on the characterization of micellar preparations in terms of their morphology, stability, longevity in circulation, and ability to spontaneously accumulate in experimental tumors via the enhanced permeability and retention (EPR) effect are presented. The review also considers the preparation of targeted immunomicelles with specific antibodies attached to their surface. Available in vivo results on the efficiency of anticancer drugs incorporated into plain micelles and immunomicelles in animal models are also discussed.

Enhancement of Polymer Cytocompatibility by Nanostructuring of Polymer Surface

Czech Academy of Sciences Publication Activity Database

Slepička, P.; Kasálková-Slepičková, N.; Bačáková, Lucie; Kolská, Z.; Švorčík, V.

2012-01-01

Roč. 2012, č. 2012 (2012), ID527403 ISSN 1687-4110 R&D Projects: GA ČR(CZ) GBP108/12/G108 Institutional support: RVO:67985823 Keywords : polymer cytocompatibility * polymer surface * nanotechnology Subject RIV: EI - Biotechnology ; Bionics Impact factor: 1.547, year: 2012

Effect of calcium chelators on physical changes in casein micelles in concentrated micellar casein solutions

NARCIS (Netherlands)

Kort, de E.J.P.; Minor, M.; Snoeren, T.H.M.; Hooijdonk, van A.C.M.; Linden, van der E.

2011-01-01

The effect of calcium chelators on physical changes of casein micelles in concentrated micellar casein solutions was investigated by measuring calcium-ion activity, viscosity and turbidity, and performing ultracentrifugation. The highest viscosities were measured on addition of sodium

Self-consistent field theoretic simulations of amphiphilic triblock copolymer solutions: Polymer concentration and chain length effects

Directory of Open Access Journals (Sweden)

X.-G. Han

2014-06-01

Full Text Available Using the self-consistent field lattice model, polymer concentration φP and chain length N (keeping the length ratio of hydrophobic to hydrophilic blocks constant the effects on temperature-dependent behavior of micelles are studied, in amphiphilic symmetric ABA triblock copolymer solutions. When chain length is increased, at fixed φP, micelles occur at higher temperature. The variations of average volume fraction of stickers φcos and the lattice site numbers Ncols at the micellar cores with temperature are dependent on N and φP, which demonstrates that the aggregation of micelles depends on N and φP. Moreover, when φP is increased, firstly a peak appears on the curve of specific heat CV for unimer-micelle transition, and then in addition a primary peak, the secondary peak, which results from the remicellization, is observed on the curve of CV. For a long chain, in intermediate and high concentration regimes, the shape of specific heat peak markedly changes, and the peak tends to be a more broad peak. Finally, the aggregation behavior of micelles is explained by the aggregation way of amphiphilic triblock copolymer. The obtained results are helpful in understanding the micellar aggregation process.

Differential thermodynamic signature of carbon nanomaterials using amphiphilic micellar probe

Science.gov (United States)

Bhattacharyya, Tamoghna; Dasgupta, Anjan Kr

2018-04-01

The thermodynamic signature of single-wall carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs) and reduced graphene oxide (rG-O) using amphiphilic micellar probe has been explored. The study reveals an intricate correlation between nano-surface topology and calorimetric profile of SWCNTs, MWCNTs and rG-O. The critical micelle concentration (CMC) is found to be sensitive to the topological diversity of nanomaterials. The study explores a thermodynamic approach to characterize the nano-surface topology of SWCNTs, MWCNTs and graphene surface.

Rheological Properties of Hydrophobically Associative Copolymers Prepared in a Mixed Micellar Method Based on Methacryloxyethyl-dimethyl Cetyl Ammonium Chloride as Surfmer

Directory of Open Access Journals (Sweden)

Rui Liu

2014-01-01

Full Text Available A novel cationic surfmer, methacryloxyethyl-dimethyl cetyl ammonium chloride (DMDCC, is synthesized. The micellar properties, including critical micelle concentration and aggregation number, of DMDCC-SDS mixed micelle system are studied using conductivity measurement and a steady-state fluorescence technique. A series of water-soluble associative copolymers with acrylamide and DMDCC are prepared using the mixed micellar polymerization. Compared to conventional micellar polymerization, this new method could not only reasonably adjust the length of the hydrophobic microblock, that is, NH, but also sharply reduce the amount of surfactant. Their rheological properties related to hydrophobic microblock and stickers are studied by the combination of steady flow and linear viscoelasticity experiments. The results indicate that both the hydrophobic content and, especially the length of the hydrophobic microblock are the dominating factors effecting the intermolecular hydrophobic association. The presence of salt influences the dynamics of copolymers, resulting in the variation of solution characters. Viscosity measurement indicates that mixed micelles between the copolymer chain and SDS molecules serving as junction bridges for transitional network remarkably enhance the viscosity. Moreover, the microscopic structures of copolymers at different experimental conditions are conducted by ESEM. This method gives us an insight into the preparation of hydrophobically associative water-soluble copolymers by cationic surfmer-anionic surfactant mixed micellar polymerization with good performance.

Responsive micellar films of amphiphilic block copolymer micelles: control on micelle opening and closing.

Science.gov (United States)

Chen, Zhiquan; He, Changcheng; Li, Fengbin; Tong, Ling; Liao, Xingzhi; Wang, Yong

2010-06-01

We reported the deliberate control on the micelle opening and closing of amphiphilic polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) micellar films by exposing them to selective solvents. We first treated the micellar films with polar solvents including ethanol and water (pH = 4, 8, and 12) that have different affinities to P2VP. We observed opening of the micelles in all the cases. Both the size of opened pores and the opening rate are dependent on the solvency of different solvents for P2VP. We then explored the closing behavior of the opened micelles using solvents having different affinities to PS. We found that the opened micelles were recovered to their initial closed micelle forms. The recovery was accompanied by a slow micelle disassociation process which gradually reduced the micelle size. The rates of the micelle closing and disassociation are also dependent on the solvency of different solvents for PS.

Mechanistic Analysis of Cocrystal Dissolution as a Function of pH and Micellar Solubilization.

Science.gov (United States)

Cao, Fengjuan; Amidon, Gordon L; Rodriguez-Hornedo, Nair; Amidon, Gregory E

2016-03-07

The purpose of this work is to provide a mechanistic understanding of the dissolution behavior of cocrystals under the influence of ionization and micellar solubilization. Mass transport models were developed by applying Fick's law of diffusion to dissolution with simultaneous chemical reactions in the hydrodynamic boundary layer adjacent to the dissolving cocrystal surface to predict the pH at the dissolving solid-liquid interface (i.e., interfacial pH) and the flux of cocrystals. To evaluate the predictive power of these models, dissolution studies of carbamazepine-saccharin (CBZ-SAC) and carbamazepine-salicylic acid (CBZ-SLC) cocrystals were performed at varied pH and surfactant concentrations above the critical stabilization concentration (CSC), where the cocrystals were thermodynamically stable. The findings in this work demonstrate that the pH dependent dissolution behavior of cocrystals with ionizable components is dependent on interfacial pH. This mass transport analysis demonstrates the importance of pH, cocrystal solubility, diffusivity, and micellar solubilization on the dissolution rates of cocrystals.

Removal of phenol from synthetic waste water using Gemini micellar-enhanced ultrafiltration (GMEUF)

Energy Technology Data Exchange (ETDEWEB)

Zhang, Wenxiang [MOE Key Laboratory of Regional Energy and Environmental Systems Optimization, Resources and Environmental Research Academy, North China Electric Power University, Beijing 102206 (China); Huang, Guohe, E-mail: huang@iseis.org [MOE Key Laboratory of Regional Energy and Environmental Systems Optimization, Resources and Environmental Research Academy, North China Electric Power University, Beijing 102206 (China); Wei, Jia [Faculty of Engineering and Applied Science, University of Regina, Regina, Saskatchewan, Canada S4S 0A2 (Canada); Li, Huiqin; Zheng, Rubing; Zhou, Ya [MOE Key Laboratory of Regional Energy and Environmental Systems Optimization, Resources and Environmental Research Academy, North China Electric Power University, Beijing 102206 (China)

2012-10-15

Highlights: Black-Right-Pointing-Pointer Gemini surfactant micellar enhanced ultrafiltration was used to remove phenol. Black-Right-Pointing-Pointer The effect of different hydrophilic head groups of surfactant was analyzed. Black-Right-Pointing-Pointer SEM, ATR-FTIR and mercury porosimeter were applied to elucidate membrane fouling. Black-Right-Pointing-Pointer Gemini surfactant had superior performance in comparing with conventional surfactant. - Abstract: Comprehensive studies were conducted on the phenol wastewater ultrafiltration (UF) with the help of various concentrations of cationic Gemini surfactant (N1-dodecyl-N1,N1,N2,N2-tetramethyl-N2-octylethane-1,2-diaminium bromide, CG), conventional cationic surfactant (dodecyl trimethyl ammonium bromide, DTAB), anionic surfactant (sodium dodecyl sulfate, SDS) and nonionic surfactant ((dodecyloxy)polyethoxyethanol, Brij35). A flat sheet module with polyethersulfone (PES) membrane was employed in this investigation. The effects of feed concentration (phenol and surfactant) on the retention of phenol and surfactant, permeate flux and membrane fouling by micelles were evaluated. The distribution coefficient (D), the loading of the micelles (L{sub m}) and the equilibrium distribution constant (K) were also utilized to estimate the micellar-enhanced ultrafiltration ability for phenol. Scanning electron microscope (SEM), Fourier transform infrared spectrometer with attenuated total reflectance accessory (ATR-FTIR) and mercury porosimeter were applied to analyze membrane surface morphology, membrane material characteristics and membrane fouling for the original and fouled membranes. Based on the above analysis, the performance of the selected Gemini surfactant was proved superior in the following aspects: retention of phenol/surfactant (peak value is 95.8% for phenol retention), permeate flux and membrane fouling with respect to other conventional surfactants possessing equal alkyl chain length. These results demonstrated

The Nature of the Micellar Stern Region As Studied by Reaction Kinetics. 2

NARCIS (Netherlands)

Buurma, Niklaas J.; Serena, Paola; Blandamer, Michael J.; Engberts, Jan B.F.N.

2004-01-01

The nature of rate-retarding effects of cationic micelles on the water-catalyzed hydrolyses of a series of para-substituted 1-benzoyl-1,2,4-triazoles (1a-f) and 1-benzoyl-3-phenyl-1,2,4-triazole (2) has been studied using kinetic methods. A comparison is drawn between medium effects in the micellar

A theory of phase separation in asphaltene-micellar solutions

Energy Technology Data Exchange (ETDEWEB)

Pacheco Sanchez, Juan H. [Instituto Mexicano del Petroleo, Mexico D.F. (Mexico)

2001-08-01

A theory of phase separation in micellar solutions of asphaltene in aromatic hydrocarbons was reported in this paper, based on both the approach of the phase behavior of amphiphile/water micelles, and the self-association of asphaltene in aromatic core. Several experimental techniques have been used by different investigators showing the existence of some kind of critical micellar concentration (CMC) on asphaltenes in aromatic solutions. So, at least asphaltene-monomer and asphaltene-micellar phases are experimentally demonstrated facts. These two phases are the main purpose in this report on a theoretical model. Some results show the temperature versus asphaltene concentration phase diagram. The phase diagram is examined against the limited critical micelle concentration data for asphaltenes-in-toluene systems. Such phase diagram is also qualitatively examined against an experimental demonstration of phase separation. The asphaltene-micelle growth depends on the parameter K responsible for the shape and size of it. At the same time, parameter K depends on both the number of asphaltene-monomer associated in the asphaltene-micelle, and the chemical potentials in the interior and in the periphery of the micelle. An expression for getting the number of asphaltene-monomers self-associated in the asphaltene-micelle was obtained. [Spanish] Se reporta una teoria de separacion de fases en soluciones micelares de asfalteno en hidrocarburos aromaticos, basada tanto en la conducta de fase de micelas formadas por anififilos en agua como en la autoasociacion de asfaltenos en nucleos aromaticos. Se han usado diversas tecnicas experimentales por diferentes investigadores que demuestran la existancia de algun tipo de concentracion micelar critica (CMC) de soluciones de asfaltenos en aromaticos. Entonces, al menos las fases de asfalteno-monomerico y de asfalteno-micelar son hechos experimentalmente demostrados. Esta dos fases son el principal proposito de este reporte en un modelo

Application of Surfactant Micellar Solutions as Extractants and Mobile Phases for TLC-Determination of Purine Bases and Doping Agents in Biological Liquids

Directory of Open Access Journals (Sweden)

Daria Victorovna Yedamenko

2015-04-01

Full Text Available Separation of caffeine and its metabolites (theophylline and theobromine and doping agents (spironolactone, propranolol, and ephedrine and determination of caffeine in serum sample and propranolol and ephedrine in urine were studied on normal-phase thin layers (“Sorbfil-UV-254”. Aqueous organic solvents and aqueous micellar surfactant solutions were compared as the mobile phases for separation. The acceptable separation of purine bases and doping agents was achieved by micellar Thin Layer Chromatography and normal-phase Thin Layer Chromatography. Anionic surfactant solution with added 1-propanol was the best eluent as for caffeine, theophylline, and theobromine separation, as for doping agents. The best characteristics of caffeine extraction from serum, and propranolol and ephedrine from urine were achieved when micellar eluent based on non-ionic Tween-80 surfactant was used. DOI: http://dx.doi.org/10.17807/orbital.v7i1.632

RAFT Synthesis and Self-Assembly of Free-Base Porphyrin Cored Star Polymers

Directory of Open Access Journals (Sweden)

Lin Wu

2011-01-01

Full Text Available Reversible addition fragmentation chain transfer (RAFT synthesis and self-assembly of free-base porphyrin cored star polymers are reported. The polymerization, in the presence of a free-base porphyrin cored chain transfer agent (CTA-FBP, produced porphyrin star polymers with controlled molecular weights and narrow polydispersities for a number of monomers including N, N-dimethylacrylamide (DMA and styrene (St. Well-defined amphiphilic star block copolymers, P-(PS-PDMA4 and P-(PDMA-PS4 (P: porphyrin, were also prepared and used for self-assembly studies. In methanol, a selective solvent for PDMA, spherical micelles were observed for both block copolymers as characterized by TEM. UV-vis studies suggested star-like micelles were formed from P-(PS-PDMA4, while P-(PDMA-PS4 aggregated into flower-like micelles. Spectrophotometric titrations indicated that the optical response of these two micelles to external ions was a function of micellar structures. These structure-related properties will be used for micelle studies and functional material development in the future.

Deracemization of bilirubin as the marker of the chirality of micellar aggregates.

Science.gov (United States)

Sorrenti, Alessandro; Altieri, Barbara; Ceccacci, Francesca; Di Profio, Pietro; Germani, Raimondo; Giansanti, Luisa; Savelli, Gianfranco; Mancini, Giovanna

2012-01-01

The deracemization of bilirubin in micellar aggregates of structurally correlated chiral surfactants was studied by circular dichroism experiments and exploited as the marker of the expression of chirality of the aggregates. The obtained results suggest that the hydrophobic interactions control the transfer of chirality from the monomers to the aggregates, and that different regions of the same aggregate might feature opposite enantiorecognition capabilities. Copyright © 2011 Wiley-Liss, Inc.

Marginalism, quasi-marginalism and critical phenomena in micellar solutions

International Nuclear Information System (INIS)

Reatto, L.

1986-01-01

The observed nonuniversal critical behaviour of some micellar solutions is interpreted in terms of quasi-marginalism, i.e. the presence of a coupling which scales with an exponent very close to the spatial dimensionality. This can give rise to a preasymptotic region with varying effective critical exponents with a final crossover to the Ising ones. The reduced crossover temperature is estimated to be below 10 -6 . The exponents β and γ measured in C 12 e 5 are in good agreement with the scaling law expected to hold for the effective exponents. The model considered by Shnidman is found unable to explain the nonuniversal critical behaviour

Conducting polymer hydrogels

Czech Academy of Sciences Publication Activity Database

Stejskal, Jaroslav

2017-01-01

Roč. 71, č. 2 (2017), s. 269-291 ISSN 0366-6352 R&D Projects: GA ČR(CZ) GA16-02787S Institutional support: RVO:61389013 Keywords : aerogel * conducting polymers * conductivity Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 1.258, year: 2016

Preparation of pH-sensitive amphiphilic block star polymers, their self-assembling characteristics and release behavior on encapsulated molecules

KAUST Repository

Song, Xiaowan

2016-05-28

Poly(ethylene glycol) (PEG), a polymer with excellent biocompatibility, was widely used to form nanoparticles for drug delivery applications. In this paper, based on PEG, a series of pH-sensitive amphiphilic block star polymers of poly(ethylene glycol)-block-poly(ethoxy ethyl glycidyl ether) (PEG-b-PEEGE) with different hydrophobic length were synthesized by living anionic ring-opening polymerization method. The products were characterized using 1H NMR and gel permeation chromatography. These copolymers could self-assemble in aqueous solution to form micellar structure with controlled morphologies. Transmission electron microscopy showed that the nanoparticles are spherical or rodlike with different hydrophilic mass fractions. The pH response of polymeric aggregates from PEG-b-PEEGE was detected by fluorescence probe technique at different pH. A pH-dependent release behavior was observed and pH-responsiveness of PEG-b-PEEGE was affected by the hydrophobic block length. These results demonstrated that star-shaped polymers (PEG-b-PEEGE) are attractive candidates as anticancer drug delivery carriers. © 2016 Springer-Verlag Berlin Heidelberg

Micellar and analytical implications of a new potentiometric PVC sensor based on neutral ion-pair complexes of dodecylmethylimidazolium bromide-sodium dodecylsulfate.

Science.gov (United States)

Sanan, Reshu; Mahajan, Rakesh Kumar

2013-03-15

With an aim to characterize the micellar aggregates of imidazolium based ionic liquids, a new potentiometric PVC sensor based on neutral ion-pair complexes of dodecylmethylimidazolium bromide-sodium dodecylsulfate (C12MeIm(+)DS(-)) has been developed. The electrode exhibited a linear response for the concentration range of 7.9×10(-5)-9.8×10(-3) M with a super-Nernstian slope of 92.94 mV/decade, a response time of 5 s and critical micellar concentration (cmc) of 10.09 mM for C12MeImBr. The performance of the electrode in investigating the cmc of C12MeImBr in the presence of two drugs [promazine hydrochloride (PMZ) and promethazine hydrochloride (PMT)] and three triblock copolymers (P123, L64 and F68) has been found to be satisfactory on comparison with conductivity measurements. Various micellar parameters have been evaluated for the binary mixtures of C12MeImBr with drugs and triblock copolymers using Clint's, Rubingh's, and Motomura's approach. Thus the electrode offers a simple, straightforward and relatively fast technique for the characterization of micellar aggregates of C12MeImBr, complementing existing conventional techniques. Further, the analytical importance of proposed C12MeIm(+)-ISE as end point indicator in potentiometric titrations and for direct determination of cationic surfactants [cetylpyridinium chloride (CPC), tetradecyltrimethylammonium bromide (TTAB), benzalkonium chloride (BC)] in some commercial products was judged by comparing statistically with classical two-phase titration methods. Copyright © 2013 Elsevier Inc. All rights reserved.

Advanced polymer chemistry of organometallic anions

International Nuclear Information System (INIS)

Chamberlin, R.M.; Abney, K.D.; Balaich, G.J.; Fino, S.A.

1997-01-01

This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The objective of the project was to prepare and characterize new polymers incorporating cobalt dicarbollide. Specific goals were to prepare polymerizable cobalt dicarbollide monomers using the nucleophilic substitution route discovered in laboratories and to establish the reaction conditions required to form polymers from these complexes. This one-year project resulted in two publications (in press), and provided the foundation for further investigations into polymer synthesis and characterization using cobalt dicarbollide and other metallocarboranes. Interest in synthesizing organometallic polymers containing the cobalt bis(dicarbollide) anion is motivated by their possible application as cation exchange materials for the remediation of cesium-137 and strontium-90 from nuclear wastes

Jet A fuel recovery using micellar flooding: Design and implementation.

Science.gov (United States)

Kostarelos, Konstantinos; Lenschow, Søren R; Stylianou, Marinos A; de Blanc, Phillip C; Mygind, Mette Marie; Christensen, Anders G

2016-09-01

Surfactants offer two mechanisms for recovering NAPLs: 1) to mobilize NAPL by reducing NAPL/water interfacial tension, and; 2) to increase the NAPL's aqueous solubility-called solubilization-as an enhancement to pump & treat. The second approach has been well-studied and applied successfully in several pilot-scale and a few full-scale tests within the last 15years, known as Surfactant Enhanced Aquifer Remediation (SEAR). A useful source of information for this second approach is the "Surfactant-enhanced aquifer remediation (SEAR) design manual" from the U.S. Navy Facilities Engineering Command. Few attempts, however, have been made at recovering NAPLs using the mobilization approach presented in this paper. Now, a full-scale field implementation of the mobilization approach is planned to recover an LNAPL (Jet A fuel) from a surficial sand aquifer located in Denmark using a smaller amount of surfactant solution and fewer PVs of throughput compared with the SEAR approach. The approach will rely on mobilizing the LNAPL so that it is recovered ahead of the surfactant microemulsion, also known as a micellar flood. This paper will review the laboratory work performed as part of the design for a full-scale implementation of a micellar flood. Completed lab work includes screening of surfactants, phase behavior and detailed salinity scans of the most promising formulations, and generating a ternary diagram to be used for the numerical simulations of the field application. The site owners and regulators were able to make crucial decisions such as the anticipated field results based on this work. Copyright © 2016 Elsevier B.V. All rights reserved.

One electron reduction and absorption characteristics of Cresyl violet in micellar medium

International Nuclear Information System (INIS)

Gawandi, Vijay B.; Guha, S.N.; Hari Mohan

2000-01-01

Effect of surfactant micelles on absorption characteristics of Cresyl violet (CV) and on its redox reactions have been studied. Among the various surfactants investigated anionic surfactants particularly sodium lauryl sulfate (SLS) and sodium dodecyl benzene sulfonate (SDDBS) showed marked effect on these properties. Reactions of hydrated electron in these micellar media were studied using the technique of nanosecond pulse radiolysis. Results of other surfactants, viz.BSS, CTAB and TritonX-100 have also been presented. (author)

DYNAMICS OF POLYMERS AT INTERFACES; FINAL

International Nuclear Information System (INIS)

SMITH, G.S.; MAJEWSKI, J.

1999-01-01

This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). This project addresses fundamental questions concerning the behavior of polymers at interfaces: (1) What processes control the formation of an adsorbed layer on a clean surface? (2) What processes control the displacement of preadsorbed polymers? (3) Can one accurately predict the structure of polymer layers? To answer these questions, using neutron reflectivity, we have studied adsorbed layers of the polymer poly(methyl methacrylate) (PMMA) onto a quartz substrate. The polymer density profiles were derived from the neutron reflectivity data. We have shown that dry films exhibit behavior predicted by mean-field theory in that the equilibrated layer thickness scales with the molecular weight of the polymer. Also, we find that the profiles of the polymers in solution qualitatively agree with those predicted by reflected random walk (RRW) theories, yet the profiles are not in quantitative agreement

Investigation of some locally water-soluble natural polymers as circulation loss control agents during oil fields drilling

Directory of Open Access Journals (Sweden)

A.M. Alsabagh

2014-03-01

Full Text Available Eliminating or controlling lost circulation during drilling process is costly and time-consuming. Polymers play an important role in mud loss control for their viscosity due to their high molecular weight. In this paper, three natural cellulosic polymers (carboxymethyl cellulose, guar gum and potato starch were investigated as lost circulation control material by measuring different filtration parameters such as; spurt loss, fluid loss and permeability plugging tester value according to the American Petroleum Institute (API standard. The experiments were conducted in a permeability plugging apparatus (PPA at a differential pressure of 100 and 300 psi, using 10, 60 and 90 ceramic discs. From the obtained data, it was found that the 0.1% from the carboxymethyl cellulose exhibited the best results in the filtration parameters among 0.3% guar gum and 0.6% potato starch. At the same time the carboxymethyl cellulose (CMC enhanced the rheological properties of the drilling mud better than the two other used natural polymers in the term of gel strength, thixotropy, plastic and apparent viscosity. These results were discussed in the light of the adsorption and micellar formation.

Structural study of concentrated micellar solutions

International Nuclear Information System (INIS)

Zemb, Thomas

1985-01-01

This research thesis reports the study of the structure of concentrated soap-water binary micelles with a comparison of measurements of light, neutrons and X-ray scattering, and the relaxation induced by paramagnetic ions adsorbed at the interface. In the first part, the author discusses the specific sensitivity ranges of different experimental techniques, outlines the resolution which can be obtained with scattering experiments, and proposes a critical analysis of results published in the relevant literature. In a second part, the author discusses the compared results of the application of various techniques (magnetic resonance, X-light and neutron scattering) on the two most used model systems: sodium octanoate and sodium dodecyl sulfate (SDS) in solution. Then, the author addresses the case of ternary systems: study of the influence of the presence of a co-surfactant on the structure, study of the effect of interfacial charge on the micellar structure, use of the same previous quantitative methods to study the disturbances brought to the structure due to the presence of reactants [fr

Multicompartment micellar aggregates of linear ABC amphiphiles in solvents selective for the C block: A Monte Carlo simulation

KAUST Repository

Zhu, Yutian; Yu, Haizhou; Wang, Yongmei; Cui, Jie; Kong, Weixin; Jiang, Wei

2012-01-01

the simulations and the detailed phase diagrams for the ABC amphiphiles with different block lengths are obtained. The simulation results reveal that the micellar structure is largely controlled by block length, solvent quality, and incompatibility between

Dynamic and structural characterisation of micellar solutions of surfactants by spin relaxation and translational diffusion

International Nuclear Information System (INIS)

Mahieu, Nathalie

1992-01-01

The work reported in this research thesis aimed at characterizing micellar phases formed by some surfactants (sodium carboxylates) in aqueous solution. After some recalls on nuclear magnetic resonance dealing with spin relaxation (longitudinal relaxation, transverse relaxation, relaxation in the rotating coordinate system, and crossed relaxation), and comments on the dipolar mechanism responsible of relaxation phenomena, the author presents the methods used for relaxation parameter measurement and the data processing software issued from experiments. He presents experiments which allowed the self-diffusion coefficient to be measured, reports data processing, and addresses problems of special diffusion and of coherence transfers during diffusion measurements. Results of proton relaxation measurements are then presented and discussed. They are used to determine the micellar state of the studied carboxylates. The case of the oleate is also addressed. Measurements of carbon-13 relaxation times are reported, and exploited in terms of structural parameters by using the Relaxator software. An original method of the hetero-nuclear Overhauser method is presented, and used to assess the average distance between water molecules and micelle surface [fr

Evaluation of the numerical solution of polymer flooding; Avaliacao da solucao numerica da injecao de polimeros em reservatorios de petroleo

Energy Technology Data Exchange (ETDEWEB)

Teixeira, Vinicius Ligiero; Pires, Adolfo Puime; Bedrikovetsky, Pavel G. [Universidade Estadual do Norte Fluminense (UENF), Macae, RJ (Brazil). Lab. de Engenharia e Exploracao do Petroleo (LENEP)

2004-07-01

Enhanced Oil Recovery (EOR) methods include injection of different fluids into reservoirs to improve oil displacement. The EOR methods may be classified into the following kinds: injection of chemical solutions, injection of solvents and thermal methods. The chemical fluids most commonly injected are polymers, surfactants, micellar solutions, etc. Displacement of oil by any of these fluids involves complex physico-chemical processes of interphase mass transfer, phase transitions and transport properties changes. These processes can be divided into two main categories: thermodynamical and hydrodynamical ones. They occur simultaneously during the displacement, and are coupled in the modern mathematical models of EOR. The model for one-dimensional displacement of oil by polymer solutions is analyzed in this paper. The Courant number is fixed, and we compare the results of different runs of a numerical simulator with the analytical solution of this problem. Each run corresponds to a different spatial discretization. (author)

Spectroscopic Behavior of Some A3B Type Tetrapyrrolic Complexes in Several Organic Solvents and Micellar Media

Directory of Open Access Journals (Sweden)

Radu Socoteanu

2011-08-01

Full Text Available The paper presents spectral studies of some unsymmetrical A3B tetrapyrrolic, porphyrin-type complexes with Cu(II and Zn(II in different solvents and micellar media aimed at estimating their properties in connection with the living cell. The results indicate that the position of the absorption and emission peaks is mostly influenced by the central metal ion and less by the environmental polarity or the peripheric substituents of the porphyrinic core. The comparison between the overall absorption and emission spectra of the compounds in methanol or cyclohexane vs. direct and reverse Triton X micellar systems, respectively, suggests for all compounds the localization at the interface between the polyethylene oxide chains and the tert-octyl-phenyl etheric residue of the Triton X-100 molecules. These findings could be important when testing the compounds embedded in liposomes or other delivery systems to the targeted cell.

Chiral separation of amino acids in biological fluids by micellar electrokinetic chromatography with laser-induced fluorescence detection.

Science.gov (United States)

Thorsén, G; Bergquist, J

2000-08-18

A method is presented for the chiral analysis of amino acids in biological fluids using micellar electrokinetic chromatography (MEKC) and laser-induced fluorescence (LIF). The amino acids are derivatized with the chiral reagent (+/-)-1-(9-anthryl)-2-propyl chloroformate (APOC) and separated using a mixed micellar separation system. No tedious pre-purification of samples is required. The excellent separation efficiency and good detection capabilities of the MEKC-LIF system are exemplified in the analysis of urine and cerebrospinal fluid. This is the first time MEKC has been reported for chiral analysis of amino acids in biological fluids. The amino acids D-alanine, D-glutamine, and D-aspartic acid have been observed in cerebrospinal fluid, and D-alanine and D-glutamic acid in urine. To the best of our knowledge no measurements of either D-alanine in cerebrospinal fluid or D-glutamic acid in urine have been presented in the literature before.

Interfaced conducting polymers

Czech Academy of Sciences Publication Activity Database

Stejskal, Jaroslav; Bober, Patrycja; Trchová, Miroslava; Nuzhnyy, Dmitry; Bovtun, Viktor; Savinov, Maxim; Petzelt, Jan; Prokeš, J.

2017-01-01

Roč. 224, February (2017), s. 109-115 ISSN 0379-6779 R&D Projects: GA ČR(CZ) GA16-02787S Institutional support: RVO:61389013 ; RVO:68378271 Keywords : polyaniline * polypyrrole * poly(p-phenylenediamine) Subject RIV: CD - Macromolecular Chemistry; CD - Macromolecular Chemistry (FZU-D) OBOR OECD: Polymer science; Polymer science (FZU-D) Impact factor: 2.435, year: 2016

Polymer electronic devices and materials.

Energy Technology Data Exchange (ETDEWEB)

Schubert, William Kent; Baca, Paul Martin; Dirk, Shawn M.; Anderson, G. Ronald; Wheeler, David Roger

2006-01-01

Polymer electronic devices and materials have vast potential for future microsystems and could have many advantages over conventional inorganic semiconductor based systems, including ease of manufacturing, cost, weight, flexibility, and the ability to integrate a wide variety of functions on a single platform. Starting materials and substrates are relatively inexpensive and amenable to mass manufacturing methods. This project attempted to plant the seeds for a new core competency in polymer electronics at Sandia National Laboratories. As part of this effort a wide variety of polymer components and devices, ranging from simple resistors to infrared sensitive devices, were fabricated and characterized. Ink jet printing capabilities were established. In addition to promising results on prototype devices the project highlighted the directions where future investments must be made to establish a viable polymer electronics competency.

Photochemical assessment of UO2+2 complexation in Triton X-100 micellar system

International Nuclear Information System (INIS)

Das, S.K.; Ganguly, B.N.

1994-01-01

This is a report on the spectral characteristics of UO 2 +2 in the excited state in the Triton X-100 micellar medium. The downward curving of the Stern-Volmer plot explains the two kinds of populations of UO 2 +2 upon micellization. A blue shift of the quenched emission is ascribed due to the collisional encounter of UO 2 +2 with the head groups of Triton X-100. (author). 5 refs., 2 figs

Surface dynamics of micellar diblock copolymer films

Science.gov (United States)

Song, Sanghoon; Cha, Wonsuk; Kim, Hyunjung; Jiang, Zhang; Narayanan, Suresh

2011-03-01

We studied the structure and surface dynamics of poly(styrene)-b-poly(dimethylsiloxane) (PS-b-PDMS) diblock copolymer films with micellar PDMS surrounded by PS shells. By `in-situ' high resolution synchrotron x-ray reflectivity and diffuse scattering, we obtained exact thickness, electron density and surface tension. A segregation layer near the top surface was appeared with increasing temperature Surface dynamics were measured as a function of film thickness and temperature by x-ray photon correlation spectroscopy. The best fit to relaxation time constants as a function of in-plane wavevectors were analyzed with a theory based on capillary waves with hydrodynamics with bilayer model Finally the viscosities for the top segregated layer as well as for the bottom layer are obtained at given temperatures This work was supported by National Research Foundation of Korea (R15-2008-006-01001-0), Seoul Research and Business Development Program (10816), and Sogang University Research Grant (2010).

Chemiluminescence from an oxidation reaction of rhodamine B with cerium(IV) in a reversed micellar medium of cetyltrimethylammonium chloride in 1-hexanol-cyclohexane/water.

Science.gov (United States)

Hasanin, Tamer H A; Tsunemine, Yusuke; Tsukahara, Satoshi; Okamoto, Yasuaki; Fujiwara, Terufumi

2011-01-01

The chemiluminescence (CL) emission, observed when rhodamine B (RB) in 1-hexanol-cyclohexane was mixed with cerium(IV) sulfate in sulfuric acid dispersed in a reversed micellar medium of cetyltrimethylammonium chloride (CTAC) in 1-hexanol-cyclohexane/water, was investigated using a flow-injection system. The CL emission from the oxidation reaction of RB with Ce(IV) was found to be stronger in the CTAC reversed micellar solution compared with an aqueous solution. Bearing on the enhancement effect of the CTAC reverse micelles on the RB-Ce(IV) CL, several studies including stopped-flow, fluorescence and electron spin resonance (ESR) spectrometries were performed. Rapid spectral changes of an intermediate in the RB-Ce(IV) reaction in the aqueous and reversed micellar solutions were successfully observed using a stopped-flow method. The effect of the experimental variables, i.e., oxidant concentration, sulfuric acid concentration, the mole fraction of 1-hexanol, water-to-surfactant molar concentration ratio, flow rate, upon the CL intensity was evaluated. Under the experimental conditions optimized for a flow-injection determination of RB based on the new reversed micellar-mediated CL reaction with Ce(IV), a detection limit of 0.08 µmol dm(-3) RB was achieved, and a linear calibration graph was obtained with a dynamic range from 0.5 to 20 µmol dm(-3). The relative standard deviation (n = 6) obtained at an RB concentration of 3 µmol dm(-3) was 3%.

Radiation Synthesis of Superabsorbent Polymers Based on Natural Polymers

International Nuclear Information System (INIS)

Sen, Murat; Hayrabolulu, Hande

2010-01-01

The objectives of proposed research contract were first synthesize superabsorbent polymers based on natural polymers to be used as disposable diapers and soil conditioning materials in agriculture, horticulture and other super adsorbent using industries. We have planned to use the natural polymers; locust beam gum, tara gum, guar gum and sodium alginate on the preparation of natural superabsorbent polymers(SAP). The aqueous solution of natural polymers and their blends with trace amount of monomer and cross-linking agents will be irradiated in paste like conditions by gamma rays for the preparation of cross-linked superabsorbent systems. The water absorption and deswellling capacity of prepared super adsorbents and retention capacity, absorbency under load, suction power, swelling pressure and pet-rewet properties will be determined. Use of these materials instead of synthetic super absorbents will be examined by comparing the performance of finished products. The experimental studies achieved in the second year of project mainly on the effect of radiation on the chemistry of sodium alginate polymers in different irradiation conditions and structure-property relationship particularly with respect to radiation induced changes on the molecular weight of natural polymers and preliminary studies on the synthesis of natural-synthetic hydride super adsorbent polymers were given in details

Analysis of micellar and vesicular lecithin and cholesterol in model bile using 1H- and 31P-NMR

NARCIS (Netherlands)

de Graaf, M. P.; Groen, A. K.; Bovée, W. M.

1995-01-01

The distribution of phospholipid and cholesterol between the vesicular and micellar phases in bile plays an important role in the formation of cholesterol gallstones. Conventional analytical procedures to determine the distribution are potentially unreliable because they disturb the distribution of

Technical note: Development and validation of a new method for the quantification of soluble and micellar calcium, magnesium, and potassium in milk.

Science.gov (United States)

Franzoi, M; Niero, G; Penasa, M; Cassandro, M; De Marchi, M

2018-03-01

Milk mineral content is a key trait for its role in dairy processes such as cheese-making, its use as source of minerals for newborns, and for all traits involving salt-protein interactions. This study investigated a new method for measuring mineral partition between soluble and micellar fractions in bovine milk after rennet coagulation. A new whey dilution step was added to correct the quantification bias due to whey trapped in curd and excluded volume. Moreover, the proposed method allowed the quantification of the diffusible volume after milk coagulation. Milk mineral content and concentration in whey, and diluted whey were quantified by acid digestion and inductively coupled plasma optical emission spectrometry. The repeatability of the method for micellar Ca, Mg, and K was between 2.07 and 8.96%, whereas reproducibility ranged from 4.01 to 9.44%. Recovery of total milk minerals over 3 spiking levels ranged from 92 to 97%. The proposed method provided an accurate estimation of micellar and soluble minerals in milk, and curd diffusible volume. Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Integration of vanadium-mixed addenda Dawson heteropolytungstate within poly(3,4-ethylenedioxythiophene) and poly(2,2'-bithiophene) films by electrodeposition from the nonionic micellar aqueous medium

Energy Technology Data Exchange (ETDEWEB)

Goral, Monika [Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw (Poland); Jouini, Mohamed, E-mail: jouini@univ-paris-diderot.f [Laboratory Interfaces, Traitements, Organisation et DYnamique des Systemes (ITODYS) UMR 7086, Universite Paris Diderot Paris 7 Batiment Lavoisier, 15 Rue Jean Antoine de Baif, 75205 Paris Cedex 13 (France); Perruchot, Christian [Laboratory Interfaces, Traitements, Organisation et DYnamique des Systemes (ITODYS) UMR 7086, Universite Paris Diderot Paris 7 Batiment Lavoisier, 15 Rue Jean Antoine de Baif, 75205 Paris Cedex 13 (France); Miecznikowski, Krzysztof; Rutkowska, Iwona A. [Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw (Poland); Kulesza, Pawel J., E-mail: pkulesza@chem.uw.edu.p [Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw (Poland)

2011-04-01

A comparative study describing immobilization of the Dawson type mixed addenda heteropolyanion, [P{sub 2}W{sub 17}VO{sub 62}]{sup 8-} into conducting polymer films of poly(3,4-ethylenedioxythiophene), PEDOT, and poly(2,2'-bithiophene), PBT, is reported. Electrosynthesis of these hybrid films was performed using a micellar aqueous solution of the nonionic surfactant, polyethylene glycol tert-octylphenyl ether (Triton X-100). Deposited composite films were characterised electrochemically and, on the whole, they exhibited fast electron transfer (ET) properties and relatively high stability towards continuous potential cycling in acidic media. In particular, PEDOT composite showed relatively faster ET properties in comparison to PBT composite. Their permeability was investigated in the presence of cationic and anionic redox probes. Our results implied good mediating capabilities of the [P{sub 2}W{sub 17}V{sup 4+}O{sub 62}]{sup 8-} anion (within the [P{sub 2}W{sub 17}V{sup 4+}O{sub 62}]{sup 8-}-PEDOT hybrid film) towards the iron (III) reduction. The specific electrocatalytic (reductive) capabilities of hybrid films were also studied by probing the reduction of bromate. The films were further characterised by X-ray photoelectron spectroscopy to establish their interfacial elemental composition. Moreover, their surface morphology was imaged by atomic force microscopy and scanning electron microscopy. Results have shown that physicochemical properties of the investigated hybrid films were affected by polymer hydrophobicity.

Covalent and non-covalent curcumin loading in acid-responsive polymeric micellar nanocarriers

Science.gov (United States)

Gao, Min; Chen, Chao; Fan, Aiping; Zhang, Ju; Kong, Deling; Wang, Zheng; Zhao, Yanjun

2015-07-01

Poor aqueous solubility, potential degradation, rapid metabolism and elimination lead to low bioavailability of pleiotropic impotent curcumin. Herein, we report two types of acid-responsive polymeric micelles where curcumin was encapsulated via both covalent and non-covalent modes for enhanced loading capacity and on-demand release. Biodegradable methoxy poly(ethylene glycol)-poly(lactic acid) copolymer (mPEG-PLA) was conjugated with curcumin via a hydrazone linker, generating two conjugates differing in architecture (single-tail versus double-tail) and free curcumin was encapsulated therein. The two micelles exhibited similar hydrodynamic size at 95 ± 3 nm (single-tail) and 96 ± 3 nm (double-tail), but their loading capacities differed significantly at 15.0 ± 0.5% (w/w) (single-tail) and 4.8 ± 0.5% (w/w) (double-tail). Under acidic sink conditions (pH 5.0 and 6.0), curcumin displayed a faster release from the single-tail nanocarrier, which was correlated to a low IC50 of 14.7 ± 1.6 (μg mL-1) compared to the value of double-tail micelle (24.9 ± 1.3 μg mL-1) in HeLa cells. The confocal imaging and flow cytometry analysis demonstrated a superior capability of single-tail micelle for intracellular curcumin delivery, which was a consequence of the higher loading capacity and lower degree of mPEG surface coverage. In conclusion, the dual loading mode is an effective means to increase the drug content in the micellar nanocarriers whose delivery efficiency is highly dependent on its polymer-drug conjugate architecture. This strategy offers an alternative nanoplatform for intracellularly delivering impotent hydrophobic agents (i.e. curcumin) in an efficient stimuli-triggered way, which is valuable for the enhancement of curcumin’s efficacy in managing a diverse range of disorders.

Separation of mercury(II), methylmercury and phenylmercury by micellar high-performance liquid chromatography on short columns

International Nuclear Information System (INIS)

Hutta, M.; Megova, S.; Halko, R.

1998-01-01

Three environmentally and agrochemically important mercury species: methylmercury, phenylmercury and mercury(II) are separated within 4 minutes as bromocomplexes by micellar liquid chromatography using very short reversed-phase (RP) C18 columns (up to 30 mm). The micellar mobile phase containing 0.05M cetyltrimethylammonium bromide (CTMA + Br - ), 1% (v/v) 2-propanol, 0.001M cyclohexylenediaminetetraacetic acid (DCTA) and sulfuric acid (pH 2) showed good selectivity in mixed reversed-phase and anion-exchange mode. The above mentioned separation order in which organomercurials are eluted far behind the void volume of the column, but before the mercury(II) peak is advantageous in all instances where mercury(II) is present in real samples in great excess. Environmental and agrochemical samples contain humic material which does not interfere in this particular system. The low cost photometric detection at 500 nm after post-column derivatization by CTMA + Br - micellized dithizone is almost free from interferences and enables detection limits at the 1-3 ng level (e.g., 0.1 ppm Hg) for 20 μl samples. (author)

Radiation decomposition of alcohols and chloro phenols in micellar systems

International Nuclear Information System (INIS)

Moreno A, J.

1998-01-01

The effect of surfactants on the radiation decomposition yield of alcohols and chloro phenols has been studied with gamma doses of 2, 3, and 5 KGy. These compounds were used as typical pollutants in waste water, and the effect of the water solubility, chemical structure, and the nature of the surfactant, anionic or cationic, was studied. The results show that anionic surfactant like sodium dodecylsulfate (SDS), improve the radiation decomposition yield of ortho-chloro phenol, while cationic surfactant like cetyl trimethylammonium chloride (CTAC), improve the radiation decomposition yield of butyl alcohol. A similar behavior is expected for those alcohols with water solubility close to the studied ones. Surfactant concentrations below critical micellar concentration (CMC), inhibited radiation decomposition for both types of alcohols. However radiation decomposition yield increased when surfactant concentrations were bigger than the CMC. Aromatic alcohols decomposition was more marked than for linear alcohols decomposition. On a mixture of alcohols and chloro phenols in aqueous solution the radiation decomposition yield decreased with increasing surfactant concentration. Nevertheless, there were competitive reactions between the alcohols, surfactants dimers, hydroxyl radical and other reactive species formed on water radiolysis, producing a catalytic positive effect in the decomposition of alcohols. Chemical structure and the number of carbons were not important factors in the radiation decomposition. When an alcohol like ortho-chloro phenol contained an additional chlorine atom, the decomposition of this compound was almost constant. In conclusion the micellar effect depend on both, the nature of the surfactant (anionic or cationic) and the chemical structure of the alcohols. The results of this study are useful for wastewater treatment plants based on the oxidant effect of the hydroxyl radical, like in advanced oxidation processes, or in combined treatment such as

Enhancement of MHC-I antigen presentation via architectural control of pH-responsive, endosomolytic polymer nanoparticles.

Science.gov (United States)

Wilson, John T; Postma, Almar; Keller, Salka; Convertine, Anthony J; Moad, Graeme; Rizzardo, Ezio; Meagher, Laurence; Chiefari, John; Stayton, Patrick S

2015-03-01

Protein-based vaccines offer a number of important advantages over organism-based vaccines but generally elicit poor CD8(+) T cell responses. We have previously demonstrated that pH-responsive, endosomolytic polymers can enhance protein antigen delivery to major histocompatibility complex class I (MHC-I) antigen presentation pathways thereby augmenting CD8(+) T cell responses following immunization. Here, we describe a new family of nanocarriers for protein antigen delivery assembled using architecturally distinct pH-responsive polymers. Reversible addition-fragmentation chain transfer (RAFT) polymerization was used to synthesize linear, hyperbranched, and core-crosslinked copolymers of 2-(N,N-diethylamino)ethyl methacrylate (DEAEMA) and butyl methacrylate (BMA) that were subsequently chain extended with a hydrophilic N,N-dimethylacrylamide (DMA) segment copolymerized with thiol-reactive pyridyl disulfide (PDS) groups. In aqueous solution, polymer chains assembled into 25 nm micellar nanoparticles and enabled efficient and reducible conjugation of a thiolated protein antigen, ovalbumin. Polymers demonstrated pH-dependent membrane-destabilizing activity in an erythrocyte lysis assay, with the hyperbranched and cross-linked polymer architectures exhibiting significantly higher hemolysis at pH ≤ 7.0 than the linear diblock. Antigen delivery with the hyperbranched and cross-linked polymer architecture enhanced in vitro MHC-I antigen presentation relative to free antigen, whereas the linear construct did not have a discernible effect. The hyperbranched system elicited a four- to fivefold increase in MHC-I presentation relative to the cross-linked architecture, demonstrating the superior capacity of the hyperbranched architecture in enhancing MHC-I presentation. This work demonstrates that the architecture of pH-responsive, endosomolytic polymers can have dramatic effects on intracellular antigen delivery, and offers a promising strategy for enhancing CD8(+) T cell

The Oral Bioavailability of Trans-Resveratrol from a Grapevine-Shoot Extract in Healthy Humans is Significantly Increased by Micellar Solubilization.

Science.gov (United States)

Calvo-Castro, Laura A; Schiborr, Christina; David, Franziska; Ehrt, Heidi; Voggel, Jenny; Sus, Nadine; Behnam, Dariush; Bosy-Westphal, Anja; Frank, Jan

2018-05-01

Grapevine-shoot extract Vineatrol30 contains abundant resveratrol monomers and oligomers with health-promoting potential. However, the oral bioavailability of these compounds in humans is low (˂1-2%). The aim of this study was to improve the oral bioavailability of resveratrol from vineatrol by micellar solubilization. Twelve healthy volunteers (six women, six men) randomly ingested a single dose of 500 mg vineatrol (30 mg trans-resveratrol, 75 mg trans-ε-viniferin) as native powder or liquid micelles. Plasma and urine were collected at baseline and over 24 h after intake. Resveratrol and viniferin were analyzed by HPLC. The area under the plasma concentration-time curve (AUC) and mean maximum plasma trans-resveratrol concentrations were 5.0-fold and 10.6-fold higher, respectively, after micellar supplementation relative to the native powder. However, no detectable amounts of trans-ε-viniferin were found in either plasma or urine. The transepithelial permeability of trans-resveratrol and trans-ε-viniferin across differentiated Caco-2 monolayers was consistent to the absorbed fractions in vivo. The oral bioavailability of trans-resveratrol from the grapevine-shoot extract Vineatrol30 was significantly increased using a liquid micellar formulation, without any treatment-related adverse effects, making it a suitable system for improved supplementation of trans-resveratrol. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

USE OF POLYMERS TO RECOVER VISCOUS OIL FROM UNCONVENTIONAL RESERVOIRS

Energy Technology Data Exchange (ETDEWEB)

Randall Seright

2011-09-30

This final technical progress report summarizes work performed the project, 'Use of Polymers to Recover Viscous Oil from Unconventional Reservoirs.' The objective of this three-year research project was to develop methods using water soluble polymers to recover viscous oil from unconventional reservoirs (i.e., on Alaska's North Slope). The project had three technical tasks. First, limits were re-examined and redefined for where polymer flooding technology can be applied with respect to unfavorable displacements. Second, we tested existing and new polymers for effective polymer flooding of viscous oil, and we tested newly proposed mechanisms for oil displacement by polymer solutions. Third, we examined novel methods of using polymer gels to improve sweep efficiency during recovery of unconventional viscous oil. This report details work performed during the project. First, using fractional flow calculations, we examined the potential of polymer flooding for recovering viscous oils when the polymer is able to reduce the residual oil saturation to a value less than that of a waterflood. Second, we extensively investigated the rheology in porous media for a new hydrophobic associative polymer. Third, using simulation and analytical studies, we compared oil recovery efficiency for polymer flooding versus in-depth profile modification (i.e., 'Bright Water') as a function of (1) permeability contrast, (2) relative zone thickness, (3) oil viscosity, (4) polymer solution viscosity, (5) polymer or blocking-agent bank size, and (6) relative costs for polymer versus blocking agent. Fourth, we experimentally established how much polymer flooding can reduce the residual oil saturation in an oil-wet core that is saturated with viscous North Slope crude. Finally, an experimental study compared mechanical degradation of an associative polymer with that of a partially hydrolyzed polyacrylamide. Detailed results from the first two years of the project may be

Optimisation of resolution in micellar electrokinetic chromatography by multivariate evaluation of electrolytes.

Science.gov (United States)

Mikaeli, S; Thorsén, G; Karlberg, B

2001-01-12

A novel approach to multivariate evaluation of separation electrolytes for micellar electrokinetic chromatography is presented. An initial screening of the experimental parameters is performed using a Plackett-Burman design. Significant parameters are further evaluated using full factorial designs. The total resolution of the separation is calculated and used as response. The proposed scheme has been applied to the optimisation of the separation of phenols and the chiral separation of (+)-1-(9-anthryl)-2-propyl chloroformate-derivatized amino acids. A total of eight experimental parameters were evaluated and optimal conditions found in less than 48 experiments.

Cost Effective Polymer Solar Cells Research and Education

Energy Technology Data Exchange (ETDEWEB)

Sun, Sam-Shajing [Norfolk State Univ, Norfolk, VA (United States)

2015-10-13

The technical or research objective of this project is to investigate and develop new polymers and polymer based optoelectronic devices for potentially cost effective (or cost competitive), durable, lightweight, flexible, and high efficiency solar energy conversion applications. The educational objective of this project includes training of future generation scientists, particularly young, under-represented minority scientists, working in the areas related to the emerging organic/polymer based solar energy technologies and related optoelectronic devices. Graduate and undergraduate students will be directly involved in scientific research addressing issues related to the development of polymer based solar cell technology.

Micellar phase boundaries under the influence of ethyl alcohol

International Nuclear Information System (INIS)

Bergeron, Denis E.

2016-01-01

The Compton spectrum quenching technique is used to monitor the effect of ethyl alcohol (EtOH) additions on phase boundaries in two systems. In toluenic solutions of the nonionic surfactant, Triton X-100, EtOH shifts the boundary separating the first clear phase from the first turbid phase to higher water:surfactant ratios. In a commonly used scintillant, Ultima Gold AB, the critical micelle concentration is not shifted. The molecular interactions behind the observations and implications for liquid scintillation counting are discussed. - Highlights: • Compton spectrum quenching technique applied to find micellar phase boundaries. • Toluenic Triton X-100 and Ultima Gold AB investigated. • Ethyl alcohol affects phase boundaries in Triton X-100, not in Ultima Gold AB. • Phase boundary observations discussed in terms of relevant molecular interactions.

Comparison of migration modeling in micellar electrokinetic chromatography by linear regression and by use of an artificial neural network

NARCIS (Netherlands)

Metting, HJ; van Zomeren, PV; van der Ley, CP; Coenegracht, PMJ; de Jong, GJ

2000-01-01

The concentrations of modifier (methanol or acetonitrile) and surfactant (sodium dodecyl sulfate SDS) in the running buffer are important factors influencing the mobility of analytes in micellar electrokinetic chromatography (MEKC). Response surfaces of the effective mobility can be used to predict

Polymer Masks for nanostructuring of graphene

DEFF Research Database (Denmark)

Shvets, Violetta

This PhD project is a part of Center for Nanostructured Graphene (CNG) activities. The aim of the project is to develop a new lithography method for creation of highly ordered nanostructures with as small as possible feature and period sizes. The method should be applicable for graphene nanostruc...... demonstrated the opening of what could be interpreted as a band gap....... polymer masks is developed. Mask fabrication is realized by microtoming of 30-60 nm thin sections from pre-aligned polymer monoliths with different morphologies. The resulting polymer masks are then transferred to both silicon and graphene substrates. Hexagonally packed hole patterns with 10 nm hole...

Correlation between the solubility of aromatic hydrocarbons in water and micellar solutions, with their normal boiling points

International Nuclear Information System (INIS)

Almgren, M.; Grieser, F.; Powell, J.R.; Thomas, J.K.

1979-01-01

A linear correlation between the logarithm of the solubility in water of aromatic hydrocarbons and their normal boiling points is shown. Similarly, the logarithm of the distribution ratio of aromatic hydrocarbons in aqueous micellar solution is shown to be linearly related to the boiling points of the hydrocarbons. 2 figures, 2 tables

Polymers for enhanced oil recovery: fundamentals and selection criteria.

Science.gov (United States)

Rellegadla, Sandeep; Prajapat, Ganshyam; Agrawal, Akhil

2017-06-01

With a rising population, the demand for energy has increased over the years. As per the projections, both fossil fuel and renewables will remain as major energy source (678 quadrillion BTU) till 2030 with fossil fuel contributing 78% of total energy consumption. Hence, attempts are continuously made to make fossil fuel production more sustainable and cheaper. From the past 40 years, polymer flooding has been carried out in marginal oil fields and have proved to be successful in many cases. The common expectation from polymer flooding is to obtain 50% ultimate recovery with 15 to 20% incremental recovery over secondary water flooding. Both naturally derived polymers like xanthan gum and synthetic polymers like partially hydrolyzed polyacrylamide (HPAM) have been used for this purpose. Earlier laboratory and field trials revealed that salinity and temperature are the major issues with the synthetic polymers that lead to polymer degradation and adsorption on the rock surface. Microbial degradation and concentration are major issues with naturally derived polymers leading to loss of viscosity and pore throat plugging. Earlier studies also revealed that polymer flooding is successful in the fields where oil viscosity is quite higher (up to 126 cp) than injection water due to improvement in mobility ratio during polymer flooding. The largest successful polymer flood was reported in China in 1990 where both synthetic and naturally derived polymers were used in nearly 20 projects. The implementation of these projects provides valuable suggestions for further improving the available processes in future. This paper examines the selection criteria of polymer, field characteristics that support polymer floods and recommendation to design a large producing polymer flooding.

Recirculation and reutilization of micellar bile lecithin.

Science.gov (United States)

Robins, S J

1975-09-01

Bile lecithins, solubilized in micellar bile salt and radiolabeled in the 1-acyl fatty acid, phosphorus, and choline positions, were infused in the small bowel of fasted rats. Absorption of each label was virtually complete after 24 h. However, these lecithins were extensively hydrolyzed in the bowel lumen as well as after absorption, and neither the fatty acid nor phosphorus was significantly retained in the enterohepatic circulation or reutilized for biliary lecithin synthesis. In contrast, while choline was also dissociated from absorbed lecithin, choline was instead retained in the liver, reincorporated into newly synthesized hepatic lecithin, and sercreted in biliary lecithin in 10-fold greater amounts than either the fatty acid or phosphorus. However, the extent of choline incorporation into bile lecithin was limited and was not further increased when free choline was directly injected into the portal vein. The data therefore suggest that although only choline of absorbed lecithin is retained in the enterohepatic circulation and preserved for new biliary lecithin synthesis, exogenous choline utilization is regulated by the size of the available hepatic pool.

In situ synthesis of Prussian blue nanoparticles within a biocompatible reverse micellar system for in vivo Cs"+ uptake

International Nuclear Information System (INIS)

Lavaud, Cyril; Kajdan, Marilyn; Long, Jerome; Larionova, Joulia; Guari, Yannick; Compte, Elsa; Maurel, Jean-Claude; Him, Josephine Lai Kee; Bron, Patrick; Oliviero, Erwan

2017-01-01

A new highly stable Prussian blue reverse micellar system comprising ultra-small Prussian blue nanoparticles in Aonyss (Peceolt, b-sitosterol, lecithin, ethanol and water) acts as an in vivo Cs"+ uptake agent presenting higher efficiency compared to commercially available Prussian blue treatment with a significant dose effect. (authors)

Micellar effect on the kinetics of oxidation of methyl blue by Ce(IV in sulfuric acid medium

Directory of Open Access Journals (Sweden)

Mohammed Hassan

2015-01-01

Full Text Available The kinetics of oxidation of methyl blue (MB by Ce(IV in aqueous and surfactant media has been carried out to explore the micellar effect on the rate and kinetic parameters of the reaction. The reaction was found to be first order with respect to both oxidant and substrate and fractional order with respect to H+. The active kinetic species of the oxidant was found to be Ce(SO4+2 based on the effect of ionic strength and sulfate ion on the rate of the reaction. The presence of micelles was found to inhibit the reaction and this effect has been explained by the association of one of the reactants with the micelles leaving the other reactant in the bulk solution. The binding constant and first order rate constant in micellar medium has been obtained by the application of pseudo-phase model to the experimental data. Interestingly, the temperature dependence of the reaction reveals that the reaction has negative activation energy in the absence of micelles, which turns to a positive value in the presence of micelles.

Application of micellar electrokinetic capillary chromatography for routine analysis of different materials

Directory of Open Access Journals (Sweden)

Injac Rade

2008-01-01

Full Text Available Micellar electrokinetic capillary chromatography (MEKC has become a popular mode among the several capillary electro-migration techniques. Most drug analysis can be performed by using MEKC because of its wide applicability. Separation of very complex mixtures, determination of drugs in the biological materials, etc., can be successfully achieved by MEKC. This review surveys typical applications of MEKC analysis. Recent advances in MEKC, especially with solid-phase extraction and large-volume sample stacking, are described. Modes of electrokinetic chromatography including MEKC, a separation theory of MEKC, environmental friendly analysis, and selectivity manipulation in MEKC are also briefly mentioned.

Influence of micellar calcium and phosphorus on rennet coagulation properties of cows milk.

Science.gov (United States)

Malacarne, Massimo; Franceschi, Piero; Formaggioni, Paolo; Sandri, Sandro; Mariani, Primo; Summer, Andrea

2014-05-01

The main requirement for milk processed in most cheese typologies is its rennet coagulation ability. Despite the increasing number of studies, the causes for abnormal coagulation of milk are not fully understood. The aim of this study was to ascertain relationships between milk characteristics and its rennet coagulation ability, focusing on the influence of calcium (Ca) and phosphorus (P). Ca and P are essential constituents of the micelles. Micellar P can be present as part of colloidal calcium phosphate (inorganic-P) or covalently bound to caseins as phosphate groups (casein-P). Eighty one herd milk samples (SCCproperties. Optimal milk was characterised by the highest contents of major constituents, protein fractions and minerals, lowest content of chloride and highest values of titratable acidity. Non-coagulating milk was characterised by the highest values of pH and the lowest of titratable acidity. At micellar level, Optimal milk showed the highest values of colloidal Ca, casein-P and colloidal Mg (g/100 g casein), while Non-coagulating milk showed the lowest values. Interestingly, there was no statistical difference regarding the content of colloidal inorganic-P (g/100 g casein) between Optimal and Non-coagulating milks. Overall, high mineralisation of the micelle (expressed as g inorganic-P/100 g casein) positively affect its rennetability. However, excessive mineralisation could lead to a reduction of the phosphate groups (g casein-P/100 g casein) available for curd formation.

Dominant role of wormlike micelles in temperature-responsive viscoelastic properties of their mixtures with polymeric chains

KAUST Repository

Molchanov, Vyacheslav S.

2013-03-01

Temperature effects on the rheological properties of viscoelastic solutions containing entangled wormlike micelles of potassium oleate and hydrophobically modified polyacrylamide were studied in a wide range of polymer concentrations. A very pronounced drop of viscosity by four orders of magnitude was observed at heating from 20 to 78 °C both in the presence and in the absence of polymer indicating that the wormlike micelles are mainly responsible for this effect. The highly thermosensitive behavior was attributed to the shortening of micellar chains induced by heating. Although the decrease in viscosity is almost the same for both surfactant and surfactant/polymer systems, the absolute values of the viscosity in the presence of polymer are by few orders of magnitude higher, which is due to the formation of a common network of entangled polymer and micellar chains. As a result, the added polymer allows one to get highly temperature responsive system that keeps viscoelastic properties in a much wider range of temperatures, which makes it very promising for various practical applications. © 2012 Elsevier Inc.

Determination of lysergic acid diethylamide (LSD) in mouse blood by capillary electrophoresis/ fluorescence spectroscopy with sweeping techniques in micellar electrokinetic chromatography.

Science.gov (United States)

Fang, Ching; Liu, Ju-Tsung; Chou, Shiu-Huey; Lin, Cheng-Huang

2003-03-01

The separation and on-line concentration of lysergic acid diethylamide (LSD) in mouse blood was achieved by means of capillary electrophoresis/fluorescence spectroscopy using sodium dodecyl sulfate (SDS) as the surfactant. Techniques involving on-line sample concentration, including sweeping micellar electrokinetic chromatography (sweeping-MEKC) and cation-selective exhaustive injection-sweep-micellar electrokinetic chromatography (CSEI-sweep-MEKC) were applied; the optimum on-line concentration and separation conditions were determined. In the analysis of an actual sample, LSD was found in a blood sample from a test mouse (0.1 mg LSD fed to a 20 g mouse; approximately 1/10 to the value of LD(50)). As a result, 120 and 30 ng/mL of LSD was detected at 20 and 60 min, respectively, after ingestion of the doses.

FOR STIMUL-RESPONSIVE POLYMERS WITH ENHANCED EFFICIENCY IN RESERVOIR RECOVERY PROCESSES

Energy Technology Data Exchange (ETDEWEB)

Charles McCormick; Roger Hester

2004-03-26

This report contains a series of terpolymers containing acrylic acid, methacrylamide and a twin-tailed hydrophobic monomer that were synthesized using micellar polymerization methods. These polymer systems were characterized using light scattering, viscometry, and fluorescence methods. Viscosity studies indicate that increasing the nonpolar character of the hydrophobic monomer (longer chain length or twin tailed vs. single tailed) results in enhanced viscosity in aqueous solutions. The interactions of these polymers with surfactants were investigated. These surfactants include sodium dodecyl sulfate (SDS), cetyl trimethyl ammonium bromide (CTAB), Triton X-100. Viscosity measurements of DiC{sub 6}AM and DiC{sub 8}AM mixtures indicate little interaction with SDS, gelation with CTAB, and hemimicelle formation followed by polymer hydrophobe solubilization with Triton X-100. The DiC{sub 10}Am terpolymer shows similar interaction behavior with CTAB and Triton X-100. However, the enhanced hydrophobic nature of the DiC{sub 10} polymer allows complex formation with SDS as confirmed by surface tensiometry. Fluorescence measurements performed on a dansyl labeled DiC{sub 10}Am terpolymer in the presence of increasing amounts of each of the surfactant indicate relative interaction strengths to be CTAB>Triton X-100>SDS. A modified model based on Yamakawa-Fujii and Odjik-Skolnick-Fixman theories was found to describe the contribution of electrostatic forces to the excluded volume of a polyelectrolyte in solution. The model was found to be valid for flexible polymer coils in aqueous salt solutions where intermolecular interactions are minimal. The model suggested that a dimensionless group of parameters termed the dimensionless viscosity should be proportional to the dimensionless ratio of solution screening length to polyion charge spacing. Several sets of experimental data from the literature and from our laboratory have been analyzed according to the model and the results

Micellar effect on metal-ligand complexes of Co(II, Ni(II, Cu(II and Zn(II with citric acid

Directory of Open Access Journals (Sweden)

Nageswara Rao Gollapalli

2009-12-01

Full Text Available Chemical speciation of citric acid complexes of Co(II, Ni(II, Cu(II and Zn(II was investigated pH-metrically in 0.0-2.5% anionic, cationic and neutral micellar media. The primary alkalimetric data were pruned with SCPHD program. The existence of different binary species was established from modeling studies using the computer program MINIQUAD75. Alkalimetric titrations were carried out in different relative concentrations (M:L:X = 1:2:5, 1:3:5, 1:5:3 of metal (M to citric acid. The selection of best chemical models was based on statistical parameters and residual analysis. The species detected were MLH, ML2, ML2H and ML2H2. The trend in variation of stability constants with change in mole fraction of the medium is explained on the basis of electrostatic and non-electrostatic forces. Distributions of the species with pH at different compositions of micellar media are also presented.

Micellar modified spectrophotometric determination of nitrobenzenes based upon reduction with tin(II), diazotisation and coupling with the Bratton-Marshall reagent.

Science.gov (United States)

Escrig-Tena, I; Alvarez Rodríguez, L; Esteve-Romero, J; García-Alvarez-Coque, M C

1998-09-01

Nitrobenzenes, such as the antibiotic chloramphenicol, the vasodilator nicardipine, and the herbicides dinitramin, dinobuton, fenitrothion, methylparathion, oxyfluorfen, parathion, pendimethalin, quintozene, and trifluralin, were determined by using a spectrophotometric method in the visible region (540 nm). The method was based on the reduction of the nitrobenzenes to arylamines with tin(II) chloride, diazotisation of the arylamines and coupling of the diazonium ions with the Bratton-Marshall reagent. The two latter reactions were performed in a micellar medium of sodium dodecyl sulphate. The linear calibration range was 2x10(-6) to 7x10(-5) M (r>0.999), with limits of detection in the 10(-7) M level, which is 2-6 fold lower with respect to the corresponding spectrophotometric procedure in non-micellar medium. The procedure was applied to the analysis of the compounds in commercial preparations (pharmaceuticals and herbicide formulations) and in water samples, with good recoveries.

Micellar induced regioselectivity in the two-step consecutive reaction of SO3(2-) with Br-(CH2CH2)n-Br (n=2-5).

Science.gov (United States)

Currie, Fredrik; Jarvoll, Patrik; Holmberg, Krister; Romsted, Laurence S; Gunaseelan, Krishnan

2007-08-15

High field (800 MHz) (1)H NMR was used to monitor the two-step consecutive reaction of excess SO(3)(2-) with symmetrical bifunctional alpha,omega-dibromoalkanes with butane (DBB), hexane (DBH), octane (DBO), and decane (DBD) chains in CTAB micelles at 25 degrees C. The first-order rate constant for the first substitution step for DBB and DBH is about 5 times faster than for the second, but the kinetics for DBO and DBD were not cleanly first-order. After 40 min, the solution contained about 80% of the intermediate bromoalkanesulfonate from DBB and DBH and the remainder is alkanedisulfonate and unreacted starting material. The same reactions were carried out in homogeneous MeOH/D(2)O solutions at 50 degrees C. The rate constants for all four alpha,omega-dibromoalkanes were first-order throughout the time course of the reaction and the same within +/-10%. However, because micellar solutions are organized on the nanoscale and bring together lipophilic and hydrophilic reactants into a small reaction volume at the micellar interface, they speed this substitution reaction considerably compared to reaction in MeOH/D(2)O. The CTAB micelles also induce a significant regioselectivity in product formation by speeding the first step of the consecutive reaction more than the second. The results are consistent with the bromoalkanesulfonate intermediates having a radial orientation within the micelles with the -CH(2)SO(3)(-) group in the interfacial region and the -CH(2)Br group directed into the micellar core such that the concentration of -CH(2)Br groups in the reactive zone, i.e., the micellar interface, is significantly reduced. These results provide the first example of self-assembled surfactant system altering the relative rates of the reaction steps of a consecutive reaction and, in doing so, enhancing monosubstitution of a symmetrically disubstituted species.

Simultaneous Extraction, Enrichment and Removal of Dyes from Aqueous Solutions Using a Magnetic Aqueous Micellar Two-Phase System

Directory of Open Access Journals (Sweden)

Shuanggen Wu

2017-12-01

Full Text Available The magnetic aqueous micellar two-phase system (MAMTPS has the advantages combined of magnetic solid phase extraction (MSPE and aqueous micellar two-phase system (AMTPS. Thus, MAMTPS based on Fe3O4 magnetic nanoparticles (MNPs and a nonionic surfactant Triton X-114 (TX-114 was developed for the extraction, enrichment and removal of three dyes (Congo red, methyl blue, and methyl violet from aqueous solutions in this study. The MNPs Fe3O4@NH2 was screened as the optimal MNPs benefiting the extraction. Then, the influencing factors of MNPs amount, TX-114 concentration, vibration time, and extraction temperature were investigated in detail. The results showed that the extraction efficiencies of three dyes almost reached 100% using MAMTPS under the optimal conditions; MAMTPS had higher extraction ability than the individual MSPE or AMTPS. Thus, MAMTPS had the advantages of simple operation, high extraction ability, easy recycling of MNPs, and short phase-separation time, which showspotential for use in the extraction and analysis of contaminants from water samples.

An Asymptotic Theory for the Re-Equilibration of a Micellar Surfactant Solution

KAUST Repository

Griffiths, I. M.; Bain, C. D.; Breward, C. J. W.; Chapman, S. J.; Howell, P. D.; Waters, S. L.

2012-01-01

Micellar surfactant solutions are characterized by a distribution of aggregates made up predominantly of premicellar aggregates (monomers, dimers, trimers, etc.) and a region of proper micelles close to the peak aggregation number, connected by an intermediate region containing a very low concentration of aggregates. Such a distribution gives rise to a distinct two-timescale reequilibration following a system dilution, known as the t1 and t2 processes, whose dynamics may be described by the Becker-Döring equations. We use a continuum version of these equations to develop a reduced asymptotic description that elucidates the behavior during each of these processes.© 2012 Society for Industrial and Applied Mathematics.

Self-association of analgesics in aqueous solution: micellar properties of dextropropoxyphene hydrochloride and methadone hydrochloride.

Science.gov (United States)

Attwood, D; Tolley, J A

1980-08-01

The solution properties of several analgesics including dextropropoxyphene hydrochloride, methadone hydrochloride, dextromoramide acid tartrate and dipipanone hydrochloride have been examined using light scattering, conductivity, vapour pressure osmometry and surface tension techniques. A micellar pattern of association was established for dextropropoxyphene hydrochloride and methadone hydrochloride and critical micelle concentrations and aggregation numbers are reported. The hydrophobic contribution to the free energy of micellization of dextropropoxyphene was determined from measurement of the critical micelle concentration in the presence of added electrolyte.

Bond strength investigation of two shot moulded polymer

DEFF Research Database (Denmark)

Islam, Mohammad Aminul

This report on the project “Bond strength investigation of two shot moulded polymers” has been submitted for fulfilling the requirements for the course “Experimental Plastic Technology – 42234” at IPL-DTU. Two shot moulding is a classic manufacturing process to combine two different polymers...... in a single product and it is getting more and more importance day by day. One of the biggest challenges of two shot moulding is to achieve a reasonably good bonding between two polymers. The purpose of this project is to investigate the effects of different process, material and machine parameters...... on the bond strength of two shot moulded polymers. For the experiments two engineering polymers (PS and ABS) were used. After all the experimental work, several parameters were found which could effectively control the bond strength of two shot moulded polymers. This report also presents different aspects...

Determination of adulteration of malachite green in green pea and some prepared foodstuffs by micellar liquid chromatography.

Science.gov (United States)

Ashok, Vipin; Agrawal, Nitasha; Durgbanshi, Abhilasha; Esteve-Romero, Josep; Bose, Devasish

2014-01-01

A simple, fast, and robust micellar LC method was developed for the separation and identification of the nonpermitted color malachite green in green pea and some ready-to-eat foodstuffs. Malachite green (4-[(4-dimethylaminophenyl) phenyl-methyl]-N,N-dimethylaniline) is a hazardous dye that is used to treat fungal and protozoan infections in fish and is a common adulterant (coloring agent) in green pea and other green vegetables because of its green color. In the present work, malachite green was determined in various foodstuffs using a direct injection technique on an RP C18 column with isocratic elution. The optimum mobile phase consisted of 0.15 M sodium dodecyl sulfate (SDS), 6% pentanol buffered at pH 5. Detection was carried out at 620 nm. Malachite green was eluted in 9.2 min without any interference caused by endogenous compounds. Linearities (r > 0.9999), intraday and interday precision (RSD less than 1.00%) in micellar media, and robustness were studied for method validation. LOD and LOQ were 0.10 and 0.25 ppm, respectively. The simplicity of the developed method makes it useful for routine analysis in the area of food QC.

Prediction of retention in micellar electrokinetic chromatography based on molecular structural descriptors by using the heuristic method

International Nuclear Information System (INIS)

Liu Huanxiang; Yao Xiaojun; Liu Mancang; Hu Zhide; Fan Botao

2006-01-01

Based on calculated molecular descriptors from the solutes' structure alone, the micelle-water partition coefficients of 103 solutes in micellar electrokinetic chromatography (MEKC) were predicted using the heuristic method (HM). At the same time, in order to show the influence of different molecular descriptors on the micelle-water partition of solute and to well understand the retention mechanism in MEKC, HM was used to build several multivariable linear models using different numbers of molecular descriptors. The best 6-parameter model gave the following results: the square of correlation coefficient R 2 was 0.958 and the mean relative error was 3.98%, which proved that the predictive values were in good agreement with the experimental results. From the built model, it can be concluded that the hydrophobic, H-bond, polar interactions of solutes with the micellar and aqueous phases are the main factors that determine their partitioning behavior. In addition, this paper provided a simple, fast and effective method for predicting the retention of the solutes in MEKC from their structures and gave some insight into structural features related to the retention of the solutes

Controlling the interparticle spacing of Au-salt loaded micelles and Au nanoparticles on flat surfaces.

Science.gov (United States)

Bansmann, J; Kielbassa, S; Hoster, H; Weigl, F; Boyen, H G; Wiedwald, U; Ziemann, P; Behm, R J

2007-09-25

The self-organization of diblock copolymers into micellar structures in an appropriate solvent allows the deposition of well ordered arrays of pure metal and alloy nanoparticles on flat surfaces with narrow distributions in particle size and interparticle spacing. Here we investigated the influence of the materials (substrate and polymer) and deposition parameters (temperature and emersion velocity) on the deposition of metal salt loaded micelles by dip-coating from solution and on the order and inter-particle spacing of the micellar deposits and thus of the metal nanoparticle arrays resulting after plasma removal of the polymer shell. For identical substrate and polymer, variation of the process parameters temperature and emersion velocity enables the controlled modification of the interparticle distance within a certain length regime. Moreover, also the degree of hexagonal order of the final array depends sensitively on these parameters.

Precision moulding of polymer micro components

DEFF Research Database (Denmark)

Tosello, Guido

2008-01-01

The present research work contains a study concerning polymer micro components manufacturing by means of the micro injection moulding (µIM) process. The overall process chain was considered and investigated during the project, including part design and simulation, tooling, process analysis, part...... optimization, quality control, multi-material solutions. A series of experimental investigations were carried out on the influence of the main µIM process factors on the polymer melt flow within micro cavities. These investigations were conducted on a conventional injection moulding machine adapted...... to the production of micro polymer components, as well as on a micro injection moulding machine. A new approach based on coordinate optical measurement of flow markers was developed during the project for the characterization of the melt flow. In-line pressure measurements were also performed to characterize...

The different-ligand complexing of europium with complexones and β-diketones in micellar solution

International Nuclear Information System (INIS)

Svetlova, I.E.; Dobrynina, N.A.; Smirnova, N.S.; Martynenko, L.I.; Evseev, A.M.; Savitskij, A.P.

1989-01-01

Method of pH-metric titration with mathematical simulation was used to study the effect of nonionic surfactant (polyoxyethyleneoctylphenyl este) on stability of europium complexes with cyclohexanediaminetetraacetic and ethylenediaminetetraacetic acids. Optimal conditions for ternary complex formation in the system Eu 3+ -complexone-β-diketone at pH 7.0-9.0 were found. Complex-compositions were determined and their stability constants were calculated. It is shown that complex stability decreases by several orders in micellar solutions, tecause β-diketone introduction to the solution decreases thermodynamic stability of complexes

Removal of Pyrethrin from Aqueous Effluents by Adsorptive Micellar Flocculation

Directory of Open Access Journals (Sweden)

Pardon K. Kuipa

2015-01-01

Full Text Available The equilibrium adsorption of pyrethrin onto aggregates formed by the flocculation of micelles of the surfactant sodium dodecyl sulphate (SDS with aluminium sulphate is reported. The experimental results were analysed using different adsorption isotherms (Langmuir, Freundlich, Redlich-Peterson, Sips, Radke-Prausnitz, Temkin, linear equilibrium, and the Dubin-Radushkevich isotherms. The Freundlich and linear equilibrium isotherms best describe the adsorption of pyrethrin onto SDS micellar flocs, with the Freundlich adsorption constant, KF, and the mass distribution coefficient, KD, of 64.266 ((mg/g(L/mg1/n and 119.65 L/g, respectively. Applicability of the Freundlich adsorption model suggests that heterogeneous surface adsorption affects the adsorption. The mean free energy value estimated using the Dubinin-Radushkevich isotherm was 0.136 kJ/mol indicating that physisorption may be predominant in the adsorption process.

Low Cost Polymer heat Exchangers for Condensing Boilers

Energy Technology Data Exchange (ETDEWEB)

Butcher, Thomas [Brookhaven National Lab. (BNL), Upton, NY (United States); Trojanowski, Rebecca [Brookhaven National Lab. (BNL), Upton, NY (United States); Wei, George [Brookhaven National Lab. (BNL), Upton, NY (United States); Worek, Michael [Brookhaven National Lab. (BNL), Upton, NY (United States)

2015-09-30

Work in this project sought to develop a suitable design for a low cost, corrosion resistant heat exchanger as part of a high efficiency condensing boiler. Based upon the design parameters and cost analysis several geometries and material options were explored. The project also quantified and demonstrated the durability of the selected polymer/filler composite under expected operating conditions. The core material idea included a polymer matrix with fillers for thermal conductivity improvement. While the work focused on conventional heating oil, this concept could also be applicable to natural gas, low sulfur heating oil, and biodiesel- although these are considered to be less challenging environments. An extruded polymer composite heat exchanger was designed, built, and tested during this project, demonstrating technical feasibility of this corrosion-resistant material approach. In such flue gas-to-air heat exchangers, the controlling resistance to heat transfer is in the gas-side convective layer and not in the tube material. For this reason, the lower thermal conductivity polymer composite heat exchanger can achieve overall heat transfer performance comparable to a metal heat exchanger. However, with the polymer composite, the surface temperature on the gas side will be higher, leading to a lower water vapor condensation rate.

Accelerated Characterization of Polymer Properties

Energy Technology Data Exchange (ETDEWEB)

R. Wroczynski; l. Brewer; D. Buckley; M. Burrell; R. Potyrailo

2003-07-30

This report describes the efforts to develop a suite of microanalysis techniques that can rapidly measure a variety of polymer properties of industrial importance, including thermal, photo-oxidative, and color stability; as well as ductility, viscosity, and mechanical and antistatic properties. Additional goals of the project were to direct the development of these techniques toward simultaneous measurements of multiple polymer samples of small size in real time using non-destructive and/or parallel or rapid sequential measurements, to develop microcompounding techniques for preparing polymers with additives, and to demonstrate that samples prepared in the microcompounder could be analyzed directly or used in rapid off-line measurements. These enabling technologies are the crucial precursors to the development of high-throughput screening (HTS) methodologies for the polymer additives industry whereby the rate of development of new additives and polymer formulations can be greatly accelerated.

Protolytic properties and complexation of DL-alpha-alanine and DL-alpha-valine and their dipeptides in aqueous and micellar solutions of surfactants

NARCIS (Netherlands)

Chernyshova, O. S.; Boychenko, Oleksandr; Abdulrahman, H.; Loginova, L. P.

In this work we investigated the effect of the micellar media of anionic (sodium dodecylsulfate, SDS), cationic (cetylpiridinium chloride, CPC) and non-ionic (Brij-35) surfactants on the protolytic properties of amino acids DL-alpha-alanine, DL-alpha-valine and dipeptides

Thermodynamics of Micellar Systems : Comparison of Mass Action and Phase Equilibrium Models for the Calculation of Standard Gibbs Energies of Micelle Formation

NARCIS (Netherlands)

Blandamer, Michael J.; Cullis, Paul M.; Soldi, L. Giorgio; Engberts, Jan B.F.N.; Kacperska, Anna; Os, Nico M. van

1995-01-01

Micellar colloids are distinguished from other colloids by their association-dissociation equilibrium in solution between monomers, counter-ions and micelles. According to classical thermodynamics, the standard Gibbs energy of formation of micelles at fixed temperature and pressure can be related to

Ascorbyl radical disproportionation in reverse micellar systems

Science.gov (United States)

Gębicki, J. L.; Szymańska-Owczarek, M.; Pacholczyk-Sienicka, B.; Jankowski, S.

2018-04-01

Ascorbyl radical was generated by the pulse radiolysis method and observed with the fast kinetic spectrophotometry within reverse micelles stabilized by AOT in n-heptane or by Igepal CO-520 in cyclohexane at different water to surfactant molar ratio, w0. Rate constants for the disproportionation of the ascorbyl radicals were smaller than those for intermicellar exchange for both type of reverse micelles and slower than those in homogeneous aqueous solutions. However, they increased with increasing w0 for AOT/n-heptane system, while they decreased for Igepal CO-520 system. The absorption spectra of ascorbic acid AOT/n-heptane reverse micellar system showed that the "pH" sensed by this molecule is lower than that in respective homogeneous aqueous solutions. The obtained results were rationalized taking into account three main factors (i) preferential location of ascorbic acid molecules in the interfacial region of the both types of reverse micelles; (ii) postulate that the pH of the interface is lower than that of the water pool of reverse micelles and (iii) different structure of the interface of the reverse micelles made by AOT in n-heptane and those formed by Igepal CO-520 I cyclohexane. Some possible consequences of these findings are discussed.

Polymers of phenylenediamines

Czech Academy of Sciences Publication Activity Database

Stejskal, Jaroslav

2015-01-01

Roč. 41, February (2015), s. 1-31 ISSN 0079-6700 R&D Projects: GA ČR(CZ) GA13-00270S Institutional support: RVO:61389013 Keywords : polyphenylenediamine * phenylenediamine * conducting polymers Subject RIV: CD - Macromolecular Chemistry Impact factor: 27.184, year: 2015

Flow-induced immobilization of glucose oxidase in nonionic micellar nanogels for glucose sensing.

Science.gov (United States)

Cardiel, Joshua J; Zhao, Ya; Tonggu, Lige; Wang, Liguo; Chung, Jae-Hyun; Shen, Amy Q

2014-10-21

A simple microfluidic platform was utilized to immobilize glucose oxidase (GOx) in a nonionic micellar scaffold. The immobilization of GOx was verified by using a combination of cryogenic electron microscopy (cryo-EM), scanning electron microscopy (SEM), and ultraviolet spectroscopy (UV) techniques. Chronoamperometric measurements were conducted on nanogel-GOx scaffolds under different glucose concentrations, exhibiting linear amperometric responses. Without impacting the lifetime and denaturation of GOx, the nonionic nanogel provides a favorable microenvironment for GOx in biological media. This flow-induced immobilization method in a nonionic nanogel host matrix opens up new pathways for designing a simple, fast, biocompatible, and cost-effective process to immobilize biomolecules that are averse to ionic environments.

Application of Fluorescence Emission for Characterization of Albendazole and Ricobendazole Micellar Systems: Elucidation of the Molecular Mechanism of Drug Solubilization Process.

Science.gov (United States)

Priotti, Josefina; Leonardi, Darío; Pico, Guillermo; Lamas, María C

2018-04-01

Albendazole (ABZ) and ricobendazole (RBZ) are referred to as class II compounds in the Biopharmaceutical Classification System. These drugs exhibit poor solubility, which profoundly affects their oral bioavailability. Micellar systems are excellent pharmaceutical tools to enhance solubilization and absorption of poorly soluble compounds. Polysorbate 80 (P80), poloxamer 407 (P407), sodium cholate (Na-C), and sodium deoxycholate (Na-DC) have been selected as surfactants to study the solubilization process of these drugs. Fluorescence emission was applied in order to obtain surfactant/fluorophore (S/F) ratio, critical micellar concentration, protection efficiency of micelles, and thermodynamic parameters. Systems were characterized by their size and zeta potential. A blue shift from 350 to 345 nm was observed when ABZ was included in P80, Na-DC, and Na-C micelles, while RBZ showed a slight change in the fluorescence band. P80 showed a significant solubilization capacity: S/F values were 688 for ABZ at pH 4 and 656 for RBZ at pH 6. Additionally, P80 micellar systems presented the smallest size (10 nm) and their size was not affected by pH change. S/F ratio for bile salts was tenfold higher than for the other surfactants. Quenching plots were linear and their constant values (2.17/M for ABZ and 2.29/M for RBZ) decreased with the addition of the surfactants, indicating a protective effect of the micelles. Na-DC showed better protective efficacy for ABZ and RBZ than the other surfactants (constant values 0.54 and 1.57/M, respectively), showing the drug inclusion into the micelles. Entropic parameters were negative in agreement with micelle formation.

Coalinga polymer demonstration project. Fourth annual report, July 1978-July 1979

Energy Technology Data Exchange (ETDEWEB)

Schultz, V.

1980-09-01

A field demonstration test of displacement mobility control in the East Coalinga Field is being conducted in order to determine the relative merits of polymer flooding and waterflooding in a medium viscosity oil reservoir. The injection pattern consists of four inverted 5-spot patterns and an updip area. Water injection began in June 1976 and continued through April 1978. Polymer injection began in May 1978 and is ongoing. The overall production performance for the pilot has been far less than expected. The current oil production rate is currently below the expected primary decline rate. The polymer injection rate is substantially below original predictions and will increase the time required to inject the designed slug volume.

Business, market and intellectual property analysis of polymer solar cells

DEFF Research Database (Denmark)

Damgaard Nielsen, Torben; Cruickshank, C.; Foged, S.

2010-01-01

and manufacturing cost leaves little room for competition on the thin film photovoltaic market. However, polymer solar cells do enable the competitive manufacture of low cost niche products and is viewed as financially viable in its currently available form in a large volume approximation. Finally, it is found......The business potential of polymer solar cells is reviewed and the market opportunities analyzed on the basis of the currently reported and projected performance and manufacturing cost of polymer solar cells. Possible new market areas are identified and described. An overview of the present patent...... and intellectual property situation is also given and a patent map of polymer solar cells is drawn in a European context. It is found that the business potential of polymer solar cells is large when taking the projections for future performance into account while the currently available performance...

Inorganic polymers and materials. Final report

Energy Technology Data Exchange (ETDEWEB)

Sneddon, Larry G.

2001-01-01

This DOE-sponsored project was focused on the design, synthesis, characterization, and applications of new types of boron and silicon polymers with a goal of attaining processable precursors to advanced ceramic materials of technological importance. This work demonstrated a viable design strategy for the systematic formation of polymeric precursors to ceramics based on the controlled functionalization of preformed polymers with pendant groups of suitable compositions and crosslinking properties. Both the new dipentylamine-polyborazylene and pinacolborane-hydridopolysilazane polymers, unlike the parent polyborazylene and other polyborosilazanes, are stable as melts and can be easily spun into polymer fibers. Subsequent pyrolyses of these polymer fibers then provide excellent routes to BN and SiNCB ceramic fibers. The ease of synthesis of both polymer systems suggests new hybrid polymers with a range of substituents appended to polyborazylene or polysilazane backbones, as well as other types of preceramic polymers, should now be readily achieved, thereby allowing even greater control over polymer and ceramic properties. This control should now enable the systematic tailoring of the polymers and derived ceramics for use in different technological applications. Other major recent achievements include the development of new types of metal-catalyzed methods needed for the polymerization and modification of inorganic monomers and polymers, and the modification studies of polyvinylsiloxane and related polymers with substituents that enable the formation of single source precursors to high-strength, sintered SiC ceramics.

Solvation dynamics in triton-X-100 and triton-X-165 micelles: Effect of micellar size and hydration

Science.gov (United States)

Kumbhakar, Manoj; Nath, Sukhendu; Mukherjee, Tulsi; Pal, Haridas

2004-09-01

Dynamic Stokes' shift measurements using coumarin 153 as the fluorescence probe have been carried out to study solvation dynamics in two nonionic micelles, viz., triton-X-100 (TX-100) and triton-X-165 (TX-165). In both the micelles, the solvent relaxation dynamics is biexponential in nature. While the fast solvation time τs1 is seen to be almost similar for both the micelles, the slow solvation time τs2 is found to be appreciably smaller in TX-165 than in TX-100 micelle. Dynamic light scattering measurements indicate that the TX-165 micelles are substantially smaller in size than that of TX-100. Assuming similar core size for both the micelles, as expected from the similar chemical structures of the nonpolar ends for both the surfactants, the Palisade layer is also indicated to be substantially thinner for TX-165 micelles than that of TX-100. The aggregation number of TX-165 micelles is also found to be substantially smaller than that of TX-100 micelles. Fluorescence spectral studies of C153 dye in the two micelles indicate that the Palisade layer of TX-165 micelles is more polar than that of TX-100 micelles. Fluorescence anisotropy measurements indicate that the microviscosity in the Palisade layer of TX-165 micelles is also lower than that of TX-100 micelles. Based on these results it is inferred that the structure of the Palisade layer of TX-165 micelles is quite loose and have higher degree hydration in comparison to that of TX-100 micelles. Due to these structural differences in the Palisade layers of TX-165 and TX-100 micelles the solvation dynamics is faster in the former micelles than in the latter. It has been further inferred that in the present systems the collective response of the water molecules at somewhat away from the probes is responsible for the faster component of the solvation time, which does not reflect much of the structural changes of the micellar Palisade layer. On the contrary, the slower solvation time component, which is mainly due to

Conducting polymers as sorbents of influenza viruses

Czech Academy of Sciences Publication Activity Database

Ivanova, V. T.; Garina, E. O.; Burtseva, E. I.; Kirillova, E. S.; Ivanova, M. V.; Stejskal, Jaroslav; Sapurina, Irina

2017-01-01

Roč. 71, č. 2 (2017), s. 495-503 ISSN 0366-6352 R&D Projects: GA ČR(CZ) GA16-02787S; GA MŠk(CZ) LH14199 Institutional support: RVO:61389013 Keywords : influenza viruses * conducting polymers * polyaniline Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 1.258, year: 2016

Amplification of Chirality through Self-Replication of Micellar Aggregates in Water

KAUST Repository

Bukhriakov, Konstantin

2015-03-17

We describe a system in which the self-replication of micellar aggregates results in a spontaneous amplification of chirality in the reaction products. In this system, amphiphiles are synthesized from two "clickable" fragments: a water-soluble "head" and a hydrophobic "tail". Under biphasic conditions, the reaction is autocatalytic, as aggregates facilitate the transfer of hydrophobic molecules to the aqueous phase. When chiral, partially enantioenriched surfactant heads are used, a strong nonlinear induction of chirality in the reaction products is observed. Preseeding the reaction mixture with an amphiphile of one chirality results in the amplification of this product and therefore information transfer between generations of self-replicating aggregates. Because our amphiphiles are capable of catalysis, information transfer, and self-assembly into bounded structures, they present a plausible model for prenucleic acid "lipid world" entities. © 2015 American Chemical Society.

Cationic polymers in water treatment: Part 1: Treatability of water with cationic polymers

Czech Academy of Sciences Publication Activity Database

Polasek, P.; Mutl, Silvestr

2002-01-01

Roč. 28, č. 1 (2002), s. 69-82 ISSN 0378-4738 R&D Projects: GA AV ČR KSK2067107 Keywords : cationic polymers * treatability * water quality Subject RIV: BK - Fluid Dynamics Impact factor: 0.481, year: 2002

Responsive Amphiphilic Polymers and Membranes for Water Remediation

National Research Council Canada - National Science Library

McCormick, Charles

1998-01-01

.... The foulant is solubilized within the micellar hydrophobic core and the stream is then passed through a microporous membrane, such that most of the organic solute and surfactant remain in the retentate...

Sunscreen synthesis and their immobilisation on polymethylmethacrylate: an integrated project in organic chemistry, polymer chemistry and photochemistry

International Nuclear Information System (INIS)

Murtinho, Dina Maria B.; Serra, Maria Elisa S.; Pineiro, Marta

2010-01-01

Dibenzalacetone and other aldol condensation products are known sunscreens commonly used in cosmetics. This type of compounds can easily be prepared in an Organic Chemistry Lab by reaction of aldehydes with ketones in basic medium. These compounds can be incorporated in poly(methyl methacrylate) and used as UV light absorbers, for example in sunglasses. This project has the advantage of using inexpensive reagents which are readily available in Chemistry Laboratories. This experiment can also be a base starting point for discussions of organic, polymer and photochemistry topics. (author)

Micelles Formed by Polypeptide Containing Polymers Synthesized Via N-Carboxy Anhydrides and Their Application for Cancer Treatment

Directory of Open Access Journals (Sweden)

Dimitrios Skoulas

2017-06-01

Full Text Available The development of multifunctional polymeric materials for biological applications is mainly guided by the goal of achieving the encapsulation of pharmaceutical compounds through a self-assembly process to form nanoconstructs that control the biodistribution of the active compounds, and therefore minimize systemic side effects. Micelles are formed from amphiphilic polymers in a selective solvent. In biological applications, micelles are formed in water, and their cores are loaded with hydrophobic pharmaceutics, where they are solubilized and are usually delivered through the blood compartment. Even though a large number of polymeric materials that form nanocarrier delivery systems has been investigated, a surprisingly small subset of these technologies has demonstrated potentially curative preclinical results, and fewer have progressed towards commercialization. One of the most promising classes of polymeric materials for drug delivery applications is polypeptides, which combine the properties of the conventional polymers with the 3D structure of natural proteins, i.e., α-helices and β-sheets. In this article, the synthetic pathways followed to develop well-defined polymeric micelles based on polypeptides prepared through ring-opening polymerization (ROP of N-carboxy anhydrides are reviewed. Among these works, we focus on studies performed on micellar delivery systems to treat cancer. The review is limited to systems presented from 2000–2017.

Solubilization of Phenol Derivatives in Polymer Micelles Formed by Cationic Block Copolymer

Directory of Open Access Journals (Sweden)

Irma Fuentes

2017-01-01

Full Text Available The aggregation of cationic block copolymers formed by polystyrene (PS and poly(ethyl-4-vinylpyridine (PS-b-PE4VP was studied in aqueous solution. Diblock copolymers of PS and poly(4-vinylpyridine were synthesized by sequential anionic polymerization using BuLi as initiator. Subsequently, the 4-vinylpyridine units were quaternized with ethyl bromide to obtain cationic PS-b-PE4VP block copolymers with different quaternization degree. The self-aggregation of cationic block copolymers was studied by fluorescence probing, whereas the morphology and size of polymer micelles were determined by transmission electronic microscopy. Results indicate that spherical micelles with sizes lower than 100 nm were formed, whereas their micropolarity decreases with increasing quaternization degree. The partition of phenols between the micellar and aqueous phase was studied by using the pseudo-phase model, and the results show that the partition coefficients increase with increasing length of the side alkyl chain and are larger for star micelles. These results are discussed in terms of three-region model.

Simultaneous Determination of Tizanidine, Nimesulide, Aceclofenac and Paracetamol in Tablets and Biological Fluids Using Micellar Liquid Chromatography.

Science.gov (United States)

Belal, Fathalla; Omar, Mahmoud A; Derayea, Sayed; Hammad, Mohamed A; Zayed, Sahar; Saleh, Safaa F

2018-03-01

A simple, sensitive and rapid micellar liquid chromatographic method was developed and validated for simultaneous determination of four drugs, namely, paracetamol (PAR), tizanidine (TZD), aceclofenac (ACF) and nimesulide (NMD). Good chromatographic separation was achieved using Cyano column and micellar mobile phase consisting of 120 mM sodium dodecyl sulfate, 25 mM phosphate buffer and 10% (V/V) butanol. The pH was adjusted to three using phosphoric acid. The total retention time was below 10 min. The analysis was performed at a flow rate of 1 mL/min and a column temperature of 40°C with direct UV detection at 230 nm. Diclofenac sodium was used as the internal standard. The proposed method was validated according to the ICH guidelines and was successfully applied to the analysis of these drugs in their tablet dosage forms with high accuracy. Limits of detection were found to be 0.03, 0.07, 0.033 and 0.11 μg/mL for PAR, ACF, TZD and NMD, respectively. The high sensitivity of developed method permitted its application to the in-vitro determination of the cited drugs in spiked human plasma and urine samples, and the obtained results were satisfactory. However, PAR could not be determined in spiked human urine because its peak overlapped with that of the urine peak.

Benzyl alcohol and block copolymer micellar lithography: a versatile route to assembling gold and in situ generated titania nanoparticles into uniform binary nanoarrays.

Science.gov (United States)

Polleux, Julien; Rasp, Matthias; Louban, Ilia; Plath, Nicole; Feldhoff, Armin; Spatz, Joachim P

2011-08-23

Simultaneous synthesis and assembly of nanoparticles that exhibit unique physicochemical properties are critically important for designing new functional devices at the macroscopic scale. In the present study, we report a simple version of block copolymer micellar lithography (BCML) to synthesize gold and titanium dioxide (TiO(2)) nanoarrays by using benzyl alcohol (BnOH) as a solvent. In contrast to toluene, BnOH can lead to the formation of various gold nanopatterns via salt-induced micellization of polystyrene-block-poly(vinylpyridine) (PS-b-P2VP). In the case of titania, the use of BCML with a nonaqueous sol-gel method, the "benzyl alcohol route", enables the fabrication of nanopatterns made of quasi-hexagonally organized particles or parallel wires upon aging a (BnOH-TiCl(4)-PS(846)-b-P2VP(171))-containing solution for four weeks to grow TiO(2) building blocks in situ. This approach was found to depend mainly on the relative lengths of the polymer blocks, which allows nanoparticle-induced micellization and self-assembly during solvent evaporation. Moreover, this versatile route enables the design of uniform and quasi-ordered gold-TiO(2) binary nanoarrays with a precise particle density due to the absence of graphoepitaxy during the deposition of TiO(2) onto gold nanopatterns. © 2011 American Chemical Society

Flow-injection fluorimetric determination of menadione using on-line photo-reduction in micellar media

Energy Technology Data Exchange (ETDEWEB)

Perez-Ruiz, Tomas; Martinez-Lozano, Carmen; Tomas, Virginia; Martin, Jesus

2004-07-01

A very sensitive fluorimetric method for the determination of menadione using a flow injection system is proposed. The method is based on the on-line reduction of menadione in dodecylsulphate micelles upon irradiation with UV light. The strong fluorescence of the reduced menadione in micellar medium is measured at 410 nm with excitation at 340 nm. The method shows a linear range between 2.42 and 245 ng ml{sup -1} and a limit of detection of 0.18 ng ml{sup -1}. The sample throughput was 90 injections per hour. The applicability of the assay was demonstrated by analysing this vitamin in commercial pharmaceutical preparations.

Flow-injection fluorimetric determination of menadione using on-line photo-reduction in micellar media

International Nuclear Information System (INIS)

Perez-Ruiz, Tomas; Martinez-Lozano, Carmen; Tomas, Virginia; Martin, Jesus

2004-01-01

A very sensitive fluorimetric method for the determination of menadione using a flow injection system is proposed. The method is based on the on-line reduction of menadione in dodecylsulphate micelles upon irradiation with UV light. The strong fluorescence of the reduced menadione in micellar medium is measured at 410 nm with excitation at 340 nm. The method shows a linear range between 2.42 and 245 ng ml -1 and a limit of detection of 0.18 ng ml -1 . The sample throughput was 90 injections per hour. The applicability of the assay was demonstrated by analysing this vitamin in commercial pharmaceutical preparations

Biodegradable micellar HPMA-based polymer-drug conjugates with betulinic acid for passive tumor targeting

Czech Academy of Sciences Publication Activity Database

Lomkova, Ekaterina A.; Chytil, Petr; Janoušková, Olga; Mueller, T.; Lucas, H.; Filippov, Sergey K.; Trhlíková, Olga; Aleshunin, P. A.; Skorik, Y. A.; Ulbrich, Karel; Etrych, Tomáš

2016-01-01

Roč. 17, č. 11 (2016), s. 3493-3507 ISSN 1525-7797 R&D Projects: GA MŠk(CZ) LO1507; GA MŠk(CZ) LQ1604; GA ČR(CZ) GA15-02986S Institutional support: RVO:61389013 Keywords : N-(2-hydroxypropyl)methacrylamide (HPMA) * polymeric micelles * drug delivery Subject RIV: CD - Macromolecular Chemistry Impact factor: 5.246, year: 2016

Online naphazoline quality control by micellar-enhanced spectrofluorimetry.

Science.gov (United States)

Peralta, Cecilia Mariana; Silva, Raúl Alejandro; Fernández, Liliana Patricia; Masi, Adriana Noemí

2011-01-01

The aim of this study was to develop a method for online spectrofluorimetric quality control of naphazoline (NPZ) in pharmaceuticals and raw drugs. A combination of a flow-injection analysis (FIA) system with micellar-enhanced fluorescence detection is presented as a powerful alternative for the rapid and sensitive analysis of naphazoline. Since NPZ shows low native fluorescence, the use of an anionic surfactant, such as sodium dodecyl sulphate (SDS), provides a considerable enhancement of fluorescence intensity and the nature of the technique allows a possible and easy adaptation to a FIA system. Using λ(exc) = 280 nm and λ(em) = 326 nm, a good linear relationship (LOL) was obtained in the range 0.003-10 µg mL(-1) with a detection limit (LOD) of 3 × 10(-4) µg mL(-1) (s/n = 3). Parameters related to the nature of the analytical signal and to the FIA manifold were optimized. Satisfactory recoveries were obtained in the analysis of commercial pharmaceutical formulations. The proposed method is simple, accurate and allows for high-speed sampling and considerably shorter analysis times. In addition, it requires inexpensive equipment and reagents and has easy operational conditions and no side effects, thus avoiding environmental pollution through toxic waste. Copyright © 2011 John Wiley & Sons, Ltd.

Separation Of N-Nitrosamines By Micellar Electrokinetic Chromatography

International Nuclear Information System (INIS)

Nur Amira Md Ali; Mohd Marsin Sanagi; Wan Aini Wan Ibrahim

2014-01-01

A simple and rapid micellar electrokinetic chromatography (MEKC) method was developed for separation of three selected N-Nitrosamines namely N-nitrosodipropylamine (NDPA), N-nitrosodibutylamine (NDBA) and N-nitrosodiphenylamine (NDPhA). The effects of composition of the buffer and its pH, concentration of surfactants on the separation and migration times of nitrosamines were investigated. The instrumental variables affecting sensitivity and resolution such as power supply and injection mode were carefully optimized. The best separation was achieved using 40 mM sodium dodecyl sulfate (SDS) as a surfactant in 10 mM phosphate buffer (pH 8.0) at a temperature of 25 degree Celsius, applied voltage of 29 kV, wavelength of 230 nm and electrokinetic injection of 9 s at 5 kV within 10 min analysis time. Excellent linearity was obtained in the concentration range of 2 to 100 μg/ mL with coefficients of determination, r 2 ≥0.979. This method showed good reproducibility with relative standard deviation (RSDs) value ranging from 2.46 % to 6.61 %. The limits of detection (LOD) and limits of quantification (LOQ) ranged from 0.16 to 0.43 μg/ mL and 0.54 to 1.44 μg/mL respectively. (author)

SALT-INDUCED TRANSITION FROM A MICELLAR TO A LAMELLAR LIQUID-CRYSTALLINE PHASE IN DILUTE MIXTURES OF ANIONIC AND NONIONIC SURFACTANTS IN AQUEOUS-SOLUTION

NARCIS (Netherlands)

SEIN, A; ENGBERTS, JBFN; VANDERLINDEN, E; VANDEPAS, JC

In dilute mixtures of anionic surfactant, sodium dodecylbenzenesulfonate (NaDoBS), and nonionic poly(ethylene oxide) alkyl monoether (C13-15E(7)) a transition from a micellar to a lamellar phase is found at high salting-out electrolyte (NaCit) concentrations. With an increase of the salt

Binding of chloroquine to ionic micelles: Effect of pH and micellar surface charge

Energy Technology Data Exchange (ETDEWEB)

Souza Santos, Marcela de, E-mail: marcelafarmausp77@gmail.com [Departamento de Física e Química, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Avenida do Café, s/n, Ribeirão Preto, São Paulo 14040-903 (Brazil); Perpétua Freire de Morais Del Lama, Maria, E-mail: mpemdel@fcfrp.usp.br [Departamento de Física e Química, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Avenida do Café, s/n, Ribeirão Preto, São Paulo 14040-903 (Brazil); Instituto Nacional de Ciência e Tecnologia de Bioanalítica, Departamento de Química Analítica, Universidade Estadual de Campinas, Cidade Universitária Zeferino Vaz, s/n, Campinas, São Paulo 13083-970 (Brazil); Siuiti Ito, Amando, E-mail: amandosi@ffclrp.usp.br [Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Avenida Bandeirantes, 3900, Ribeirão Preto, São Paulo 14040-901 (Brazil); and others

2014-03-15

The pharmacological action of chloroquine relies on its ability to cross biological membranes in order to accumulate inside lysosomes. The present work aimed at understanding the basis for the interaction between different chloroquine species and ionic micelles of opposite charges, the latter used as a simple membrane model. The sensitivity of absorbance and fluorescence of chloroquine to changes in its local environment was used to probe its interaction with cetyltrimethylammonium micelles presenting bromide (CTAB) and sulfate (CTAS) as counterions, in addition to dodecyl sulfate micelles bearing sodium (SDS) and tetramethylammonium (TMADS) counterions. Counterion exchange was shown to have little effect on drug–micelle interaction. Chloroquine first dissociation constant (pKa{sub 1}) shifted to opposite directions when anionic and cationic micelles were compared. Chloroquine binding constants (K{sub b}) revealed that electrostatic forces mediate charged drug–micelle association, whereas hydrophobic interactions allowed neutral chloroquine to associate with anionic and cationic micelles. Fluorescence quenching studies indicated that monoprotonated chloroquine is inserted deeper into the micelle surface of anionic micelles than its neutral form, the latter being less exposed to the aqueous phase when associated with cationic over anionic assemblies. The findings provide further evidence that chloroquine–micelle interaction is driven by a tight interplay between the drug form and the micellar surface charge, which can have a major effect on the drug biological activity. -- Highlights: • Chloroquine (CQ) pKa{sub 1} increased for SDS micelles and decreased for CTAB micelles. • CQ is solubilized to the surface of both CTAB and SDS micelles. • Monoprotonated CQ is buried deeper into SDS micelles than neutral CQ. • Neutral CQ is less exposed to aqueous phase in CTAB over SDS micelles. • Local pH and micellar surface charge mediate interaction of CQ with

Structural changes induced by high-pressure processing in micellar casein and milk protein concentrates.

Science.gov (United States)

Cadesky, Lee; Walkling-Ribeiro, Markus; Kriner, Kyle T; Karwe, Mukund V; Moraru, Carmen I

2017-09-01

Reconstituted micellar casein concentrates and milk protein concentrates of 2.5 and 10% (wt/vol) protein concentration were subjected to high-pressure processing at pressures from 150 to 450 MPa, for 15 min, at ambient temperature. The structural changes induced in milk proteins by high-pressure processing were investigated using a range of physical, physicochemical, and chemical methods, including dynamic light scattering, rheology, mid-infrared spectroscopy, scanning electron microscopy, proteomics, and soluble mineral analyses. The experimental data clearly indicate pressure-induced changes of casein micelles, as well as denaturation of serum proteins. Calcium-binding α S1 - and α S2 -casein levels increased in the soluble phase after all pressure treatments. Pressurization up to 350 MPa also increased levels of soluble calcium and phosphorus, in all samples and concentrations, whereas treatment at 450 MPa reduced the levels of soluble Ca and P. Experimental data suggest dissociation of calcium phosphate and subsequent casein micelle destabilization as a result of pressure treatment. Treatment of 10% micellar casein concentrate and 10% milk protein concentrate samples at 450 MPa resulted in weak, physical gels, which featured aggregates of uniformly distributed, casein substructures of 15 to 20 nm in diameter. Serum proteins were significantly denatured by pressures above 250 MPa. These results provide information on pressure-induced changes in high-concentration protein systems, and may inform the development on new milk protein-based foods with novel textures and potentially high nutritional quality, of particular interest being the soft gel structures formed at high pressure levels. The Authors. Published by the Federation of Animal Science Societies and Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

A novel, rapid and automated conductometric method to evaluate surfactant-cells interactions by means of critical micellar concentration analysis.

Science.gov (United States)

Tiecco, Matteo; Corte, Laura; Roscini, Luca; Colabella, Claudia; Germani, Raimondo; Cardinali, Gianluigi

2014-07-25

Conductometry is widely used to determine critical micellar concentration and micellar aggregates surface properties of amphiphiles. Current conductivity experiments of surfactant solutions are typically carried out by manual pipetting, yielding some tens reading points within a couple of hours. In order to study the properties of surfactant-cells interactions, each amphiphile must be tested in different conditions against several types of cells. This calls for complex experimental designs making the application of current methods seriously time consuming, especially because long experiments risk to determine alterations of cells, independently of the surfactant action. In this paper we present a novel, accurate and rapid automated procedure to obtain conductometric curves with several hundreds reading points within tens of minutes. The method was validated with surfactant solutions alone and in combination with Saccharomyces cerevisiae cells. An easy-to use R script, calculates conductometric parameters and their statistical significance with a graphic interface to visualize data and results. The validations showed that indeed the procedure works in the same manner with surfactant alone or in combination with cells, yielding around 1000 reading points within 20 min and with high accuracy, as determined by the regression analysis. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Selective micellar electrokinetic chromatographic method for simultaneous determination of some pharmaceutical binary mixtures containing non-steroidal anti-inflammatory drugs

Directory of Open Access Journals (Sweden)

Michael E. El-Kommos

2013-02-01

Full Text Available A simple and selective micellar electrokinetic chromatographic (MEKC method has been developed for the analysis of five pharmaceutical binary mixtures containing three non-steroidal anti-inflammatory drugs (NSAIDs. The investigated mixtures were Ibuprofen (IP–Paracetamol (PC, Ibuprofen (IP–Chlorzoxazone (CZ, Ibuprofen (IP–Methocarbamol (MC, Ketoprofen (KP–Chlorzoxazone (CZ and Diclofenac sodium (DS–Lidocaine hydrochloride (LC. The separation was run for all mixtures using borate buffer (20 mM, pH 9 containing 15% (v/v methanol and 100 mM sodium dodecyl sulphate (SDS at 15 kV and the components were detected at 214 nm. Different factors affecting the electrophoretic mobility of the seven investigated drugs were studied and optimized. The method was validated according to international conference of harmonization (ICH guidelines and United States pharmacopoeia (USP. The method was applied to the analysis of five pharmaceutical binary mixtures in their dosage forms. The results were compared with other reported high performance liquid chromatographic methods and no significant differences were observed. Keywords: Capillary electrophoresis, Micellar electrokinetic chromatographic method, Non-steroidal anti-inflammatory drugs, Pharmaceutical binary mixtures, Pharmaceutical analysis

Impact of Surface Active Ionic Liquids on the Cloud Points of Nonionic Surfactants and the Formation of Aqueous Micellar Two-Phase Systems.

Science.gov (United States)

Vicente, Filipa A; Cardoso, Inês S; Sintra, Tânia E; Lemus, Jesus; Marques, Eduardo F; Ventura, Sónia P M; Coutinho, João A P

2017-09-21

Aqueous micellar two-phase systems (AMTPS) hold a large potential for cloud point extraction of biomolecules but are yet poorly studied and characterized, with few phase diagrams reported for these systems, hence limiting their use in extraction processes. This work reports a systematic investigation of the effect of different surface-active ionic liquids (SAILs)-covering a wide range of molecular properties-upon the clouding behavior of three nonionic Tergitol surfactants. Two different effects of the SAILs on the cloud points and mixed micelle size have been observed: ILs with a more hydrophilic character and lower critical packing parameter (CPP formation of smaller micelles and concomitantly increase the cloud points; in contrast, ILs with a more hydrophobic character and higher CPP (CPP ≥ 1) induce significant micellar growth and a decrease in the cloud points. The latter effect is particularly interesting and unusual for it was accepted that cloud point reduction is only induced by inorganic salts. The effects of nonionic surfactant concentration, SAIL concentration, pH, and micelle ζ potential are also studied and rationalized.

.Pi.-conjugated donor and donor-acceptor metallo-polymers

Czech Academy of Sciences Publication Activity Database

Wild, A.; Schlütter, F.; Pavlov, G. M.; Friebe, Ch.; Festag, G.; Winter, A.; Hager, M. D.; Cimrová, Věra; Schubert, U.S.

2010-01-01

Roč. 31, 9-10 (2010), s. 868-874 ISSN 1022-1336 R&D Projects: GA MŠk(CZ) 1M06031; GA AV ČR IAA4050409 Institutional research plan: CEZ:AV0Z40500505 Keywords : analytical ultracentrifugation * conducting polymers * metallo-polymers Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 4.371, year: 2010

A photochemical study of uranyl ion interaction with the Triton X-100 micellar system

International Nuclear Information System (INIS)

Das, S.K.; Ganguly, B.N.

1996-01-01

This is a report on the spectroscopic characteristics of UO 2 2+ in the excited state in Triton X-100 micellar medium. It also indicates some important results of viscosity and surface tension measurements of the system which have direct relevance to the spectroscopic investigation in the excited state. The quenching of the UO 2 2+ fluorescence due to Triton X-100, upon micellization in the aqueous medium, reveals two kinds of microenvironments of the fluorophore from the Stern-Volmer plot. This has been verified by flash photolytic measurements. A blue shift of the quenched emission spectrum is ascribed to the collisional encounter of UO 2 1 + with the head groups of Triton X-100

Enantioseparation of palonosetron hydrochloride by micellar electrokinetic chromatography with sodium cholate as chiral selector.

Science.gov (United States)

Tian, Kan; Chen, Hongli; Tang, Jianghong; Chen, Xingguo; Hu, Zhide

2006-11-03

The enantioseparation of four stereoisomers of palonosetron hydrochloride by micellar electrokinetic chromatography using sodium cholate as chiral surfactant was described. Sodium cholate was shown to be effective in separating palonosetron hydrochloride stereoisomers. For method optimization, several parameters such as sodium cholate concentration, buffer pH and concentration, the types and concentration of organic modifiers and applied voltage, on the enantioseparation were evaluated and the optimum conditions were obtained as follows: 30 mM borate buffer (pH 9.40) containing 70 mM sodium cholate and 20% (v/v) methanol with an applied voltage of 20 kV. Under these conditions, baseline separation of palonosetron hydrochloride stereoisomers was achieved within 18 min.

Conducting polymer based biomolecular electronic devices

Indian Academy of Sciences (India)

Conducting polymers; LB films; biosensor microactuators; monolayers. ... have been projected for applications for a wide range of biomolecular electronic devices such as optical, electronic, drug-delivery, memory and biosensing devices.

New Solid Polymer Electrolytes for Improved Lithium Batteries

Science.gov (United States)

Hehemann, David G.

2002-01-01

The objective of this work was to identify, synthesize and incorporate into a working prototype, next-generation solid polymer electrolytes, that allow our pre-existing solid-state lithium battery to function better under extreme conditions. We have synthesized polymer electrolytes in which emphasis was placed on the temperature-dependent performance of these candidate electrolytes. This project was designed to produce and integrate novel polymer electrolytes into a lightweight thin-film battery that could easily be scaled up for mass production and adapted to different applications.

Novel Schiff base (DBDDP) selective detection of Fe (III): Dispersed in aqueous solution and encapsulated in silica cross-linked micellar nanoparticles in living cell.

Science.gov (United States)

Gai, Fangyuan; Yin, Li; Fan, Mengmeng; Li, Ling; Grahn, Johnny; Ao, Yuhui; Yang, Xudong; Wu, Xuming; Liu, Yunling; Huo, Qisheng

2018-03-15

This work demonstrated the synthesis of (4E)-4-(4-(diphenylamino)benzylideneamino)-1,2-dihydro-1,5- dimethyl-2-phenylpyrazol-3-one (DBDDP) for Fe (III) detection in aqueous media and in the core of silica cross-linked micellar nanoparticles in living cells. The free DBDDP performed fluorescence enhancement due to Fe (III)-promoted hydrolysis in a mixed aqueous solution, while the DBDDP-doped silica cross-linked micellar nanoparticles (DBDDP-SCMNPs) performed an electron-transfer based fluorescence quenching of Fe (III) in living cells. The quenching fluorescence of DBDDP-SCMNPs and the concentration of Fe (III) exhibited a linear correlation, which was in accordance with the Stern-Volmer equation. Moreover, DBDDP-SCMNPs showed a low limit of detection (LOD) of 0.1 ppm and an excellent selectivity against other metal ions. Due to the good solubility and biocompatibility, DBDDP-SCMNPs could be applied as fluorescence quenching nanosensors in living cells. Copyright © 2017 Elsevier Inc. All rights reserved.

Constrained swelling of polymer networks: characterization of vapor-deposited cross-linked polymer thin films

Czech Academy of Sciences Publication Activity Database

Dušek, Karel; Choukourov, A.; Dušková-Smrčková, Miroslava; Biederman, H.

2014-01-01

Roč. 47, č. 13 (2014), s. 4417-4427 ISSN 0024-9297 R&D Projects: GA ČR GAP101/12/1306 Institutional support: RVO:61389013 Keywords : swelling * cross-linked polymer * elasticity Subject RIV: CD - Macromolecular Chemistry Impact factor: 5.800, year: 2014

Enhancing the lateral-flow immunoassay for detection of proteins using an aqueous two-phase micellar system.

Science.gov (United States)

Mashayekhi, Foad; Le, Alexander M; Nafisi, Parsa M; Wu, Benjamin M; Kamei, Daniel T

2012-10-01

The lateral-flow (immuno)assay (LFA) has been widely investigated for the detection of molecular, macromolecular, and particle targets at the point-of-need due to its ease of use, rapid processing, and minimal power and laboratory equipment requirements. However, for some analytes, such as certain proteins, the detection limit of LFA is inferior to lab-based assays, such as the enzyme-linked immunosorbent assay, and needs to be improved. One solution for improving the detection limit of LFA is to concentrate the target protein in a solution prior to the detection step. In this study, a novel approach was used in the context of an aqueous two-phase micellar system comprised of the nonionic surfactant Triton X-114 to concentrate a model protein, namely transferrin, prior to LFA. Proteins have been shown to partition, or distribute, fairly evenly between the two phases of an aqueous two-phase system, which in turn results in their limited concentration in one of the two phases. Therefore, larger colloidal gold particles decorated with antibodies for transferrin were used in the concentration step to bind to transferrin and aid its partitioning into the top, micelle-poor phase. By manipulating the volume ratio of the two coexisting micellar phases and combining the concentration step with LFA, the transferrin detection limit of LFA was improved by tenfold from 0.5 to 0.05 μg/mL in a predictive manner. In addition to enhancing the sensitivity of LFA, this universal concentration method could also be used to improve other detection assays.

STIR: Microwave Response of Carbon Nanotubes in Polymer Nanocomposite Welds

Science.gov (United States)

2016-01-28

STIR: RDRL-ROE-M: Microwave Response of Carbon Nanotubes in Polymer Nanocomposite Welds Thrust 1 of the STIR project examines the heat response of...polymer composites loaded with carbon nanotubes (CNTs) to microwave irradiation. This involves (1) a study of how CNT loading affects dielectric...properties of polymer composites and (2) a study of how CNT loading affects the heating response to microwave radiation. Our hypothesis is that the

New Secondary Batteries Using Electronically Conductive Polymer Cathodes

Science.gov (United States)

Martin, Charles R.; White, Ralph E.

1991-01-01

A Li/Polypyrrole secondary battery was designed and built, and the effect of controlling the morphology of the polymer on enhancement of counterion diffusion in the polymer phase was explored. The experimental work was done at Colorado State University, while the mathematical modeling of the battery was done at Texas A and M University. Manuscripts and publications resulting from the project are listed.

A micellar model system for the role of zeaxanthin in the non-photochemical quenching process of photosynthesis--chlorophyll fluorescence quenching by the xanthophylls.

Science.gov (United States)

Avital, Shlomo; Brumfeld, Vlad; Malkin, Shmuel

2006-07-01

To get an insight to the mechanism of the zeaxanthin-dependent non-photochemical quenching in photosystem II of photosynthesis, we probed the interaction of some xanthophylls with excited chlorophyll-a by trapping both pigments in micelles of triton X-100. Optimal distribution of pigments among micelles was obtained by proper control of the micelle concentration, using formamide in the reaction mixture, which varies the micellar aggregation number over three orders of magnitude. The optimal reaction mixture was obtained around 40% (v/v) formamide in 0.2-0.4% (v/v) triton X-100 in water. Zeaxanthin in the micellar solution exhibited initially absorption and circular dichroism spectral features corresponding to a J-type aggregate. The spectrum was transformed over time (half-time values vary-an average characteristic figure is roughly 20 min) to give features representing an H-type aggregate. The isosbestic point in the series of spectral curves favors the supposition of a rather simple reaction between two pure J and H-types dimeric species. Violaxanthin exhibited immediately stable spectral features corresponding to a mixture of J-type and more predominately H-type dimers. Lutein, neoxanthin and beta-carotene did not show any aggregated spectral forms in micelles. The spectral features in micelles were compared to spectra in aqueous acetone, where the assignment to various aggregated types was established previously. The specific tendency of zeaxanthin to form the J-type dimer (or aggregate) could be important for its function in photosynthesis. The abilities of five carotenoids (zeaxanthin, violaxanthin, lutein, neoxanthin and beta-carotene) to quench chlorophyll-a fluorescence were compared. Zeaxanthin, in its two micellar dimeric forms, and beta-carotene were comparable good quenchers of chlorophyll-a fluorescence. Violaxanthin was a much weaker quencher, if at all. Lutein and neoxanthin rather enhanced the fluorescence. The implications to non

Solubilization of trace organics in block copolymer micelles for environmental separation using membrane extraction principles. Progress report, May 1, 1992--December 31, 1992

Energy Technology Data Exchange (ETDEWEB)

Hatton, T.A.

1992-12-01

The solubilization of a range of polycyclic aromatic hydrocarbons in block copolymer micelles has been studied as a function of polymer composition, architecture, and temperature. Micelle formation is favored at high temperatures, leading to significant enhancements in solubilization capacity. At low temperatures, however, micelles do not form and the solubilization capacity of the block copolymer solution for the organics is low; this provides a convenient method for the regeneration of micellar solutions used as ``solvents`` in the treatment of contaminated feed streams using membrane extraction principles. It has also been shown (in collaboration with K.P. Johnston of University of Texas, Austin) that supercritical CO{sub 2} can be used effectively for micelle regeneration. Theoretical calculations of the structure of block copolymer micelles in the presence and absence of solutes using self-consistent mean-field lattice theories have successfully captured the trends observed with changing polymer composition and architecture, often quantitatively. The temperature and composition dependence of the micellar properties were determined by allowing the individual polymer segments to assume both polar and non-polar conformations.

Solubilization of trace organics in block copolymer micelles for environmental separation using membrane extraction principles

Energy Technology Data Exchange (ETDEWEB)

Hatton, T.A.

1992-12-01

The solubilization of a range of polycyclic aromatic hydrocarbons in block copolymer micelles has been studied as a function of polymer composition, architecture, and temperature. Micelle formation is favored at high temperatures, leading to significant enhancements in solubilization capacity. At low temperatures, however, micelles do not form and the solubilization capacity of the block copolymer solution for the organics is low; this provides a convenient method for the regeneration of micellar solutions used as solvents'' in the treatment of contaminated feed streams using membrane extraction principles. It has also been shown (in collaboration with K.P. Johnston of University of Texas, Austin) that supercritical CO[sub 2] can be used effectively for micelle regeneration. Theoretical calculations of the structure of block copolymer micelles in the presence and absence of solutes using self-consistent mean-field lattice theories have successfully captured the trends observed with changing polymer composition and architecture, often quantitatively. The temperature and composition dependence of the micellar properties were determined by allowing the individual polymer segments to assume both polar and non-polar conformations.

Polymer OLED White Light Development Program

Energy Technology Data Exchange (ETDEWEB)

Homer Antoniadis; Vi-En Choong; Stelios Choulis; Brian Cumpston; Rahul Gupta; Mathew Mathai; Michael Moyer; Franky So

2005-12-19

OSRAM Opto Semiconductors (OSRAM) successfully completed development, fabrication and characterization of the large area, polymer based white light OLED prototype at their OLED Research and Development (R&D) facility in San Jose, CA. The program, funded by the Department of Energy (DOE), consisted of three key objectives: (1) Develop new polymer materials and device architectures--in order to improve the performance of organic light emitters. (2) Develop processing techniques--in order to demonstrate and enable the manufacturing of large area, white light and color tunable, solid state light sources. (3) Develop new electronics and driving schemes for organic light sources, including color-tunable light sources. The key performance goals are listed. A world record efficiency of 25 lm/W was established for the solution processed white organic device from the significant improvements made during the project. However, the challenges to transfer this technology from an R&D level to a large tile format such as, the robustness of the device and the coating uniformity of large area panels, remain. In this regard, the purity and the blend nature of the materials are two factors that need to be addressed in future work. During the first year, OSRAM's Materials and Device group (M&D) worked closely with the major polymer material suppliers to develop the polymer emissive technology. M&D was successful in demonstrating a 7-8 lm/W white light source which was based on fluorescent materials. However, it became apparent that the major gains in efficiency could only be made if phosphorescent materials were utilized. Thus, in order to improve the performance of the resulting devices, the focus of the project shifted towards development of solution-processable phosphorescent light emitting diodes (PHOLEDs) and device architectures. The result is a higher efficiency than the outlined project milestone.

The added value of 3D polymer deposition on textiles

NARCIS (Netherlands)

Brinks, G.J. (Ger); Warmoeskerken, M.M.C.G. (Marijn)

2013-01-01

The working hypothesis for this research project is that it is possible to develop a new functional polymer printing process for the direct application of conductive polymer onto textiles. We will use the basic extrusion technology that is currently applied in 3D printing. Thus the aim is also

Microporous conjugated polymers via homopolymerization of 2,5-diethynylthiophene

Czech Academy of Sciences Publication Activity Database

Bondarev, D.; Sivkova, Radoslava; Šuly, P.; Polášková, M.; Krejčí, O.; Křikavová, R.; Trávníček, Z.; Zukal, Arnošt; Kubů, Martin; Sedláček, J.

2017-01-01

Roč. 92, July (2017), s. 213-219 ISSN 0014-3057 R&D Projects: GA ČR(CZ) GA15-09637S Institutional support: RVO:61389013 ; RVO:61388955 Keywords : thiophene * microporous * catalysis Subject RIV: CD - Macromolecular Chemistry; CD - Macromolecular Chemistry (UFCH-W) OBOR OECD: Polymer science; Polymer science (UFCH-W) Impact factor: 3.531, year: 2016

Integrated Instrumentation for Light-Emitting Polymers Development

National Research Council Canada - National Science Library

Jen, Alex

2000-01-01

The major objective of this project is to develop an integrated instrumentation that combines the capability of performing spin coating of uniform polymer thin films under an oxygen and moisture free...

Business, market and intellectual property analysis of polymer solar cells

International Nuclear Information System (INIS)

Nielsen, Torben D.; Krebs, Frederik C.; Cruickshank, Craig; Foged, Soeren; Thorsen, Jesper

2010-01-01

The business potential of polymer solar cells is reviewed and the market opportunities analyzed on the basis of the currently reported and projected performance and manufacturing cost of polymer solar cells. Possible new market areas are identified and described. An overview of the present patent and intellectual property situation is also given and a patent map of polymer solar cells is drawn in a European context. It is found that the business potential of polymer solar cells is large when taking the projections for future performance into account while the currently available performance and manufacturing cost leaves little room for competition on the thin film photovoltaic market. However, polymer solar cells do enable the competitive manufacture of low cost niche products and is viewed as financially viable in its currently available form in a large volume approximation. Finally, it is found that the polymer solar cell technology is very poorly protected in Europe with the central patents being valid in only France, Germany, the Netherlands and the United Kingdom. Several countries with a large potential for PV such as Portugal and Greece are completely open and have apparently no relevant patents. This is viewed as a great advantage for the possible commercialization of polymer solar cells in a European setting as the competition for the market will be based on the manufacturing performance rather than domination by a few patent stakeholders. (author)

Controlling of degradation effects in radiation processing of polymers. Second RCM report

International Nuclear Information System (INIS)

2005-08-01

The research and development works carried out by the participants of the CRP (Coordinated Research Project) dealt with natural polymers, synthetic polymers and new techniques for better understanding of radiation degradation of polymers. It includes progress in radiation degradation of polysaccharides from agricultural products (including sodium alginate, carrageenans, chitosan and gum acacia); use of radiation-degradation for doping of conductive polymers; controlling degradation processes in artificial joint implants, surface treatment of materials and food packaging; stabilizer additives for radiation environments; surface treatment of materials; and application of specialized analytical techniques (positron annihilation spectroscopy, ESR, RBS, ERDA, NMR/isotopic-labeling) to gain improved understanding of radiation degradation effects and mechanisms. Projects within the RCM group span the spectrum from fundamental studies through specific technological applications. Participants from Czech Republic, Spain and Turkey benefited from scientific collaboration with Bulgaria on PAS

The role of the solvent in PMMA gel polymer\

Czech Academy of Sciences Publication Activity Database

Vondrák, J.; Musil, M.; Sedlaříková, M.; Kořínek, Radim; Bartušek, Karel; Fedorková, A.

2016-01-01

Roč. 2, č. 1 (2016), s. 6-12 E-ISSN 2300-3545 R&D Projects: GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : gel polymer electrolyte * TGA * NMR spectroscopy * conductivity * sodium polymer electrolyte Subject RIV: BH - Optics, Masers, Lasers https://www.degruyter.com/view/j/eetech.2016.2.issue-1/eetech-2016-0002/eetech-2016-0002.xml

Micellar electrokinetic chromatographic determination of triazine herbicides in water samples.

Science.gov (United States)

Li, Zhi; Zhang, Shuaihua; Yin, Xiaofang; Wang, Chun; Wang, Zhi

2014-09-01

Dispersive liquid-liquid microextraction combined with online sweeping preconcentration in micellar electrokinetic chromatography was developed for the simultaneous determination of five triazine herbicides (atrazine, simazine, propazine, prometon and simetryn) in water samples. Several experimental parameters affecting the extraction efficiencies such as the type and volume of both the extraction and dispersive solvents, the addition of salt to sample solution, the extraction time and the pH of the sample solution were investigated. Under optimum conditions, the linearity of the method was good in the range from 0.33 to 20 ng mL(-1) for simazine, propazine, atrazine and simetryn, and from 0.17 to 20 ng mL(-1) for prometon, respectively. The sensitivity enrichment factors were in the range from 1750 to 2100, depending on the compound. The limit of detection (S/N = 3) ranged from 0.05 to 0.10 ng mL(-1). The developed method was successfully applied to the analysis of the five triazines in river, ground and well waters. © The Author [2013]. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Biocatalytic synthesis of polymeric nanowires by micellar templates of ionic surfactants

Energy Technology Data Exchange (ETDEWEB)

Nazari, K., E-mail: nazarikh@ripi.ir [Research Institute of Petroleum Industry, NIOC, P.O. Box 14665-137, Tehran (Iran, Islamic Republic of); Chemistry Dept., Shahr Rey Islamic Azad University, P.O. Box 18735-334, Tehran (Iran, Islamic Republic of); Adhami, F.; Najjar-Safari, A.; Salmani, S. [Chemistry Dept., Shahr Rey Islamic Azad University, P.O. Box 18735-334, Tehran (Iran, Islamic Republic of); Mahmoudi, A. [Chemistry Dept., Karaj Islamic Azad University, Karaj (Iran, Islamic Republic of)

2011-07-15

Highlights: {yields} Soft-template production of polyguaiacol nanowire was done by peroxidase enzyme. {yields} Main advantage of this simple method is producing soluble encapsulated nanowires. {yields} Nanowire can be easily precipitated and separated by dilution with distilled water. {yields} Size tuned templates of sodium decyl sulfate (d = 2.7 nm) gave nanowires with d = 2-4 nm. {yields} Dried surfactant-coated wires recover freshly on specified and desired applications. -- Abstract: Micelle-templated polyguaiacol nanowires were successfully prepared via polymerization oxidation of guaiacol (o-methoxy phenol) by peroxidase enzyme in the presence of hydrogen peroxide at mild reaction conditions. The dimensions of the prepared nanowires were controlled by tuning the size and shape of the micelle structure via changing and controlling the type, chain length and molar concentrations of the ionic surfactant. The progress of the reaction and estimation of the size of soft micellar templates were followed by UV-Vis spectroscopy and dynamic light scattering (DLS). The resulting micelle encapsulated or purified polyguaiacol nanowires were characterized using transmission electron microscopy (TEM).

Biocatalytic synthesis of polymeric nanowires by micellar templates of ionic surfactants

International Nuclear Information System (INIS)

Nazari, K.; Adhami, F.; Najjar-Safari, A.; Salmani, S.; Mahmoudi, A.

2011-01-01

Highlights: → Soft-template production of polyguaiacol nanowire was done by peroxidase enzyme. → Main advantage of this simple method is producing soluble encapsulated nanowires. → Nanowire can be easily precipitated and separated by dilution with distilled water. → Size tuned templates of sodium decyl sulfate (d = 2.7 nm) gave nanowires with d = 2-4 nm. → Dried surfactant-coated wires recover freshly on specified and desired applications. -- Abstract: Micelle-templated polyguaiacol nanowires were successfully prepared via polymerization oxidation of guaiacol (o-methoxy phenol) by peroxidase enzyme in the presence of hydrogen peroxide at mild reaction conditions. The dimensions of the prepared nanowires were controlled by tuning the size and shape of the micelle structure via changing and controlling the type, chain length and molar concentrations of the ionic surfactant. The progress of the reaction and estimation of the size of soft micellar templates were followed by UV-Vis spectroscopy and dynamic light scattering (DLS). The resulting micelle encapsulated or purified polyguaiacol nanowires were characterized using transmission electron microscopy (TEM).

Determination of Critical Micellar Concentration of Homologous 2-Alkoxyphenylcarbamoyloxyethyl-Morpholinium Chlorides

Directory of Open Access Journals (Sweden)

Lenka Stopková

2018-05-01

Full Text Available The critical micellar concentrations of selected alkyloxy homologues of local anesthetic 4-(2-{[(2-alkoxyphenylcarbamoyl]oxy}ethylmorpholin-4-ium chloride with nc = 2, 4, 5, 6, 7, 8, and 9 carbons in alkyloxy tail were determined by absorption spectroscopy in the UV–vis spectral region with the use of a pyrene probe. Within the homologous series of the studied amphiphilic compounds, the ln(cmc was observed to be dependent linearly on the number of carbon atoms nc in the hydrophobic tail: ln(cmc = 0.705–0.966 nc. The Gibbs free energy, necessary for the transfer of the methylene group of the alkoxy chain from the water phase into the inner part of the micelle at the temperature of 25 °C and pH ≈ 4.5–5.0, was found to be −2.39 kJ/mol. The experimentally determined cmc values showed good correlations with the predicted values of the bulkiness of the alkoxy tail expressed as the molar volume of substituent R, as well as with the surface tension of the compounds.

O-(β-hydroxyethylrutosides determination by micellar flow injection (FI-spectrofluorimetry

Directory of Open Access Journals (Sweden)

Cecilia Mariana Peralta

2014-12-01

Full Text Available A simple, eco-friendly, sensitive and economic flow injection spectrofluorimetric method was developed for the determination of O-(β-hydroxyethylrutosides. The procedure was based on the use of an anionic surfactant such as sodium dodecyl sulfate to provide an appreciable O-(β-hydroxyethylrutosides fluorescence enhancement, increasing considerably the sensitivity of detection. All the variables affecting the fluorescence intensity were studied and optimized. The flow rate was 5 mL/min with detection at 450 nm (after excitation at 346 nm. A linear correlation between drug amount and peak area was established for O-(β-hydroxyethylrutosides in the range of 0.01–200 µg/mL with a detection limit of 0.001 µg/mL (s/n=3. Validation processes were performed by recovering studies with satisfactory results. The new methodology can be employed for the routine analysis of O-(β-hydroxyethylrutosides in bulks as well as in commercial formulations. Keywords: O-(β-hydroxyethylrutosides, Micellar enhancement, Flow injection, Spectrofluorimetry, Pharmaceuticals

Overview of ENEA's Projects on lithium batteries

Science.gov (United States)

Alessandrini, F.; Conte, M.; Passerini, S.; Prosini, P. P.

The increasing need of high performance batteries in various small-scale and large-scale applications (portable electronics, notebooks, palmtops, cellular phones, electric vehicles, UPS, load levelling) in Italy is motivating the R&D efforts of various public and private organizations. Research of lithium batteries in Italy goes back to the beginning of the technological development of primary and secondary lithium systems with national know-how spread in various academic and public institutions with a few private stakeholders. In the field of lithium polymer batteries, ENEA has been dedicating significant efforts in almost two decades to promote and carry out basic R&D and pre-industrial development projects. In recent years, three major national projects have been performed and coordinated by ENEA in co-operation with some universities, governmental research organizations and industry. In these projects novel polymer electrolytes with ceramic additives, low cost manganese oxide-based composite cathodes, environmentally friendly process for polymer electrolyte, fabrication processes of components and cells have been investigated and developed in order to fulfill long-term needs of cost-effective and highly performant lithium polymer batteries.

Physically persistent stabilizers by functionalization of polymers

Czech Academy of Sciences Publication Activity Database

Pospíšil, Jan; Habicher, W. D.; Nešpůrek, Stanislav

2001-01-01

Roč. 164, - (2001), s. 389-399 ISSN 1022-1360. [Reactive Polymers in Inhomogeneous Systems, in Melts and at Interfaces. Dresden, 16.07.2000-19.07.2000] R&D Projects: GA MŠk ME 184; GA MŠk ME 372; GA AV ČR IAA1050901; GA ČR GA106/98/0700; GA AV ČR KSK4050111 Institutional research plan: CEZ:AV0Z4050913 Keywords : nonvolatile antioxidants * photostabilizers * polymers Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.634, year: 2001

Investigation of the possibilities for application of NORM into polymer materials

OpenAIRE

Srebrenkoska, Vineta

2016-01-01

The main aim of the proposed STSM project is to perform: • Comparison of fly ash characteristics (chemical composition, granulometry and density) from different origins: Slovenia and Macedonia. • Characterization of the polymer materials: thermoset and thermoplastic. • Estimate the possibilities for preparing of the composites based on fly ash as NORM material from different origins and polymers. The analyses of the inorganic fillers and organic polymer matrices will be made in or...

Conducting polymer colloids, hydrogels, and cryogels: common start to various destinations

Czech Academy of Sciences Publication Activity Database

Stejskal, Jaroslav; Bober, Patrycja

2018-01-01

Roč. 296, č. 5 (2018), s. 989-994 ISSN 0303-402X R&D Projects: GA ČR(CZ) GA16-02787S Institutional support: RVO:61389013 Keywords : conducting polymer * polyaniline * colloidal dispersion Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 1.723, year: 2016

Conductive polymer composites with carbonic fillers: Shear induced electrical behaviour

Czech Academy of Sciences Publication Activity Database

Starý, Zdeněk; Krückel, J.

2018-01-01

Roč. 139, 14 March (2018), s. 52-59 ISSN 0032-3861 R&D Projects: GA ČR(CZ) GA17-05654S; GA MŠk(CZ) LO1507 Institutional support: RVO:61389013 Keywords : polymer-matrix composites * carbon fibres * electrical properties Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer sci ence Impact factor: 3.684, year: 2016

Novel, Solvent-Free, Single Ion Conductive Polymer Electrolytes

National Research Council Canada - National Science Library

Florjanczyk, Zbigniew

2008-01-01

This project report concerns studies on the synthesis of new polymer electrolytes for application in lithium and lithium-ion batteries characterized by limited participation of anions in the transport...

Industrialization of polymer solar cells - phase 1

Energy Technology Data Exchange (ETDEWEB)

Lauritzen, H.; Krebs, F.C. [Technical Univ. of Denmark. DTU Energy Conversion, DTU Risoe Campus, Roskilde (Denmark); Andersen, Rasmus B. [Mekoprint A/S, Stoevrimg (Denmark); Bork, J.; Bentzen, B.

2012-03-15

A three-phased project with the objective to industrialize DTU's basic polymer solar cell technology was started in the summer of 2009. The technology comprises a specific design of the polymer solar cell and a corresponding roll-to-roll manufacturing process. This basic technology is referred to as ProcessOne in the open literature. The present report relates to the project's phase 1.The key tasks in phase 1 are to stream-line DTU's tech-nology for the industrial utilization, to demonstrate production according to this stream-lined technology at Mekoprint A/S and finally to fertilize the market for polymer solar cells by demonstrating their use in appli-cations that harmonize with their present maturity level. The main focus in the stream-lining of DTU's technology has been to demonstrate a convincing rate of reduction for the production cost, and thereby make a competitive price plausible. This has been materialized as a learning curve showing that the polymer technology presently develops considerably faster than the silicon technology. The polymer solar cells will, under the assumption that both technologies follow a projection of the learning curve, gain a cost-leading position within a reasonable time. A production cost of 5 Euro/Wp has already been demonstrated in DTU's pilot plant, and a road map for the further decrease to 1 Euro/Wp is drawn. This target is expected to be reached in 2013 in the ongoing phase 2 of the project. Another activity essential for the industrialization has been the launch of specialized materials, equipment and services required for the processing of DTU's polymer solar cells. Relevant products and services are made available for sale on DTU's homepage, www.energyconversion.dtu.dk. A production line for polymer solar cells has been established at Mekoprint. For this a retrofit solution was chosen where the core of an existing screen-printing line was dismantled and fitted to a slot-die printing head manufactured in DTU's workshop

Temperature-induced phase separation and hydration in aqueous polymer solutions studied by NMR and IR spectroscopy: comparison of poly(N-vinylcaprolactam) and acrylamide-based polymers

Czech Academy of Sciences Publication Activity Database

Spěváček, Jiří; Dybal, Jiří

2014-01-01

Roč. 336, č. 1 (2014), s. 39-46 ISSN 1022-1360. [International IUPAC Conference on Polymer-Solvent Complexes and Intercalates /9./ - POLYSOLVAT-9. Kiev, 11.09.2012-14.09.2012] R&D Projects: GA ČR GA202/09/1281 Institutional support: RVO:61389013 Keywords : aqueous polymer solutions * FT-IR * NMR Subject RIV: CD - Macromolecular Chemistry

A pH-responsive wormlike micellar system of a noncovalent interaction-based surfactant with a tunable molecular structure.

Science.gov (United States)

Kang, Wanli; Wang, Pengxiang; Fan, Haiming; Yang, Hongbin; Dai, Caili; Yin, Xia; Zhao, Yilu; Guo, Shujun

2017-02-08

Responsive wormlike micelles are very useful in a number of applications, whereas it is still challenging to create dramatic viscosity changes in wormlike micellar systems. Here we developed a pH-responsive wormlike micellar system based on a noncovalent constructed surfactant, which is formed by the complexation of N-erucamidopropyl-N,N-dimethylamine (UC 22 AMPM) and citric acid at the molar ratio of 3 : 1 (EACA). The phase behavior, aggregate microstructure and viscoelasticity of EACA solutions were investigated by macroscopic appearance observation, rheological and cryo-TEM measurements. It was found that the phase behavior of EACA solutions undergoes transition from transparent viscoelastic fluids to opalescent solutions and then phase separation with white floaters upon increasing the pH. Upon increasing the pH from 2.03 to 6.17, the viscosity of wormlike micelles in the transparent solutions continuously increased and reached ∼683 000 mPa s at pH 6.17. As the pH was adjusted to 7.31, the opalescent solution shows a water-like flowing behaviour and the η 0 rapidly declines to ∼1 mPa s. Thus, dramatic viscosity changes of about 6 magnitudes can be triggered by varying the pH values without any deterioration of the EACA system. This drastic variation in rheological behavior is attributed to the pH dependent interaction between UC 22 AMPM and citric acid. Furthermore, the dependence on concentration and temperature of the rheological behavior of EACA solutions was also studied to assist in obtaining the desired pH-responsive viscosity changes.

Sequential optimization of methotrexate encapsulation in micellar nano-networks of polyethyleneimine ionomer containing redox-sensitive cross-links.

Science.gov (United States)

Abolmaali, Samira Sadat; Tamaddon, Ali; Yousefi, Gholamhossein; Javidnia, Katayoun; Dinarvand, Rasoul

2014-01-01

A functional polycation nanonetwork was developed for delivery of water soluble chemotherapeutic agents. The complexes of polyethyleneimine grafted methoxy polyethylene glycol (PEI-g-mPEG) and Zn(2+) were utilized as the micellar template for cross-linking with dithiodipropionic acid, followed by an acidic pH dialysis to remove the metal ion from the micellar template. The synthesis method was optimized according to pH, the molar ratio of Zn(2+), and the cross-link ratio. The atomic force microscopy showed soft, discrete, and uniform nano-networks. They were sensitive to the simulated reductive environment as determined by Ellman's assay. They showed few positive ζ potential and an average hydrodynamic diameter of 162±10 nm, which decreased to 49±11 nm upon dehydration. The ionic character of the nano-networks allowed the achievement of a higher-loading capacity of methotrexate (MTX), approximately 57% weight per weight, depending on the cross-link and the drug feed ratios. The nano-networks actively loaded with MTX presented some suitable properties, such as the hydrodynamic size of 117±16 nm, polydispersity index of 0.22, and a prolonged swelling-controlled release profile over 24 hours that boosted following reductive activation of the nanonetwork biodegradation. Unlike the PEI ionomer, the nano-networks provided an acceptable cytotoxicity profile. The drug-loaded nano-networks exhibited more specific cytotoxicity against human hepatocellular carcinoma cells if compared to free MTX at concentrations above 1 μM. The enhanced antitumor activity in vitro might be attributed to endocytic entry of MTX-loaded nano-networks that was found in the epifluorescence microscopy experiment for the fluorophore-labeled nano-networks.

Polymer nanocomposites: polymer and particle dynamics

KAUST Repository

Kim, Daniel

2012-01-01

Polymer nanocomposites containing nanoparticles smaller than the random coil size of their host polymer chains are known to exhibit unique properties, such as lower viscosity and glass transition temperature relative to the neat polymer melt. It has been hypothesized that these unusual properties result from fast diffusion of the nanostructures in the host polymer, which facilitates polymer chain relaxation by constraint release and other processes. In this study, the effects of addition of sterically stabilized inorganic nanoparticles to entangled cis-1,4-polyisoprene and polydimethylsiloxane on the overall rheology of nanocomposites are discussed. In addition, insights about the relaxation of the host polymer chains and transport properties of nanoparticles in entangled polymer nanocomposites are presented. The nanoparticles are found to act as effective plasticizers for their entangled linear hosts, and below a critical, chemistry and molecular-weight dependent particle volume fraction, lead to reduced viscosity, glass transition temperature, number of entanglements, and polymer relaxation time. We also find that the particle motions in the polymer host are hyperdiffusive and at the nanoparticle length scale, the polymer host acts like a simple, ideal fluid and the composites\\' viscosity rises with increasing particle concentration. © 2012 The Royal Society of Chemistry.

Application des techniques de diffusion de la lumière des rayons x et des neutrons à l'étude des systèmes colloïdaux. Deuxième partie : étude des différents systèmes : polymères en solution à l'état solide, solutions micellaires, systèmes fractals Application of Light, X-Ray and Neutron Diffusion Techniques to the Study of Colloidal Systems. Part Two: Research on Different Systems: Polymers in Solution in the Solid State, Micellar Solutions, Fractals Systems

Directory of Open Access Journals (Sweden)

Espinat D.

2006-11-01

article takes up polymer and colloidal solutions. Particular attention is paid to the importance of scattering techniques for characterizing polymers in solution and micellar solutions. A look is also taken at the information that central scattering can provide on the macrostructure of crystallized or amorphous polymers in a solid state. Many systems have a structure of the fractal type. After describing several examples, the article demonstrates that scattering methods can provide some information about materials, and especially about the fractal dimension.

Conducting polymers: Synthesis and industrial applications

Energy Technology Data Exchange (ETDEWEB)

Gottesfeld, S. [Los Alamos National Laboratory, NM (United States)

1995-05-01

The Conducting Polymer project funded by the AIM Materials Program is developing new methods for the synthesis of electronically conducting polymers and is evaluating new industrial applications for these materials which will result in significant reductions in energy usage or industrial waste. The applications specifically addressed during FY 1994 are electrochemical capacitors and membranes for gas separation. As an active material in electrochemical capacitors, conducting polymers have the potential of storing large amounts of electrical energy in low cost materials. Such devices are needed in electronics for power failure back-up and peak power, in power supplies for filtering, and in electric vehicles for peak power and load leveling. As a gas electrically adapt the membrane for specific gas combinations. Potential energy savings in the US. for this application are estimated at 1 to 3 quads/yr.

Diffusion and localization of o-Ps in Dsub(2)O determined from positron annihilation in SDS micellar solutions

International Nuclear Information System (INIS)

Vass, Sz.; Kajcsos, Zs.; Molnar, B.

1985-04-01

A microscopic diffusion model is presented for the determination of orthopositronium (o-Ps) lifetime in micellar solutions. Among other parameters, the lifetime density function depends on the o-Ps diffusion coefficient in the water phase. Orthopositronium diffusion coefficients are determined by fitting this lifetime density function to positron annihilation spectra obtained from 1 mol/dmsup(3) solution of sodium dodecylsulphate (SDS) in Dsub(2)O at different temperatures. The activation energy of the o-Ps diffusion in Dsub(2)O obtained from the Arrhenius-plot as Esub(a)=(0.9sub(22)+-0.1sub(03)) eV indicates strong localization. (author)

Coupling the Alkaline-Surfactant-Polymer Technology and The Gelation Technology to Maximize Oil Production

Energy Technology Data Exchange (ETDEWEB)

Malcolm Pitts; Jie Qi; Dan Wilson; Phil Dowling; David Stewart; Bill Jones

2005-12-01

Performance and produced polymer evaluation of four alkaline-surfactant-polymer projects concluded that only one of the projects could have benefited from combining the alkaline-surfactant-polymer and gelation technologies. Cambridge, the 1993 Daqing, Mellott Ranch, and the Wardlaw alkaline-surfacant-polymer floods were studied. An initial gel treatment followed by an alkaline-surfactant-polymer flood in the Wardlaw field would have been a benefit due to reduction of fracture flow. Numerical simulation demonstrated that reducing the permeability of a high permeability zone of a reservoir with gel improved both waterflood and alkaline-surfactant-polymer flood oil recovery. A Minnelusa reservoir with both A and B sand production was simulated. A and B sands are separated by a shale layer. A sand and B sand waterflood oil recovery was improved by 196,000 bbls or 3.3% OOIP when a gel was placed in the B sand. Alkaline-surfactant-polymer flood oil recovery improvement over a waterflood was 392,000 bbls or 6.5% OOIP. Placing a gel into the B sand prior to an alkaline-surfactant-polymer flood resulted in 989,000 bbl or 16.4% OOIP more oil than only water injection. A sand and B sand alkaline-surfactant-polymer flood oil recovery was improved by 596,000 bbls or 9.9% OOIP when a gel was placed in the B sand.

DEVELOPMENT OF A LOW COST CAMERA FOR AGING ACCELERATED POLYMERS

Directory of Open Access Journals (Sweden)

Carlos Henrique Duarte Felisbino

2018-03-01

Full Text Available The objective of this paper is to describe the design, construction and testing of a low cost chamber for accelerated aging of polymers that meets a low and high ultraviolet radiation cycle on the test specimens in accordance with ASTM G154. The methodology was based on the survey of the standards related to the tests of accelerated aging of polymers and of the existing equipment, providing the subsidies for the development of the project, which was validated by the construction and evaluation of its performance. The camera control is performed by an Arduino-based electronic system and uses commercially available components that meet project specifications. The equipment met the requirements for both the specifications and the low cost and will integrate the laboratories of the University of Mogi das Cruzes (UMC, Villa-Lobos campus, to carry out tests on polymer materials.

NATURAL GAS HYDRATES STORAGE PROJECT PHASE II. CONCEPTUAL DESIGN AND ECONOMIC STUDY

Energy Technology Data Exchange (ETDEWEB)

R.E. Rogers

1999-09-27

DOE Contract DE-AC26-97FT33203 studied feasibility of utilizing the natural-gas storage property of gas hydrates, so abundantly demonstrated in nature, as an economical industrial process to allow expanded use of the clean-burning fuel in power plants. The laboratory work achieved breakthroughs: (1) Gas hydrates were found to form orders of magnitude faster in an unstirred system with surfactant-water micellar solutions. (2) Hydrate particles were found to self-pack by adsorption on cold metal surfaces from the micellar solutions. (3) Interstitial micellar-water of the packed particles were found to continue forming hydrates. (4) Aluminum surfaces were found to most actively collect the hydrate particles. These laboratory developments were the bases of a conceptual design for a large-scale process where simplification enhances economy. In the design, hydrates form, store, and decompose in the same tank in which gas is pressurized to 550 psi above unstirred micellar solution, chilled by a brine circulating through a bank of aluminum tubing in the tank employing gas-fired refrigeration. Hydrates form on aluminum plates suspended in the chilled micellar solution. A low-grade heat source, such as 110 F water of a power plant, circulates through the tubing bank to release stored gas. The design allows a formation/storage/decomposition cycle in a 24-hour period of 2,254,000 scf of natural gas; the capability of multiple cycles is an advantage of the process. The development costs and the user costs of storing natural gas in a scaled hydrate process were estimated to be competitive with conventional storage means if multiple cycles of hydrate storage were used. If more than 54 cycles/year were used, hydrate development costs per Mscf would be better than development costs of depleted reservoir storage; above 125 cycles/year, hydrate user costs would be lower than user costs of depleted reservoir storage.

Shape-selective synthesis of non-micellar cobalt oxide (CoO) nanomaterials by microwave irradiations

International Nuclear Information System (INIS)

Kundu, Subrata; Jayachandran, M.

2013-01-01

Shape-selective formation of CoO nanoparticles has been developed using a simple one-step in situ non-micellar microwave (MW) heating method. CoO NPs were synthesized by mixing aqueous CoCl 2 ·6H 2 O solution with poly (vinyl) alcohol (PVA) in the presence of sodium hydroxide (NaOH). The reaction mixture was irradiated using MW for a total time of 2 min. This process exclusively generated different shapes like nanosphere, nanosheet, and nanodendrite structures just by tuning the Co(II) ion to PVA molar ratios and controlling other reaction parameters. The proposed synthesis method is efficient, straightforward, reproducible, and robust. Other than in catalysis, these cobalt oxide nanomaterials can be used for making pigments, battery materials, for developing solid state sensors, and also as an anisotropy source for magnetic recording.Graphical Abstract

Tuning the probe location on zwitterionic micellar system with variation of pH and addition of surfactants with different alkyl chains: solvent and rotational relaxation studies.

Science.gov (United States)

Banerjee, Chiranjib; Mandal, Sarthak; Ghosh, Surajit; Rao, Vishal Govind; Sarkar, Nilmoni

2012-09-13

In this manuscript, we have modulated the location of an anionic probe, Coumarin-343 (C-343) in a zwitterionic (N-hexadecyl-N,N-dimethylammonio-1-propanesulfonate (SB-16)) micellar system by three different approaches. The effect of addition of the surfactant sodium dodecyl sulfate (SDS) and the room temperature ionic liquid (RTIL), 1-ethyl-3-methylimidazolium octylsulfate (EmimOs) and N,N-dimethylethanol hexanoate (DAH), to the micellar solution has been studied. The effect of pH variation has been studied as well using solvent and rotational measurements. Migration of the anionic probe, C-343, from the palisade layer of SB-16 micelle to the bulk water has been observed to varying extents with the addition of SDS and EmimOs. The effect is much more pronounced in the presence of SDS and can be ascribed to the presence of the long alkyl (dodecyl) chain on SDS which can easily orient itself and fuse inside the SB-16 micelle and facilitate the observed migration of the probe molecule. This phenomenon is confirmed by faster solvation and rotational relaxation of the investigated probe molecule. The analogous fusion process is difficult in case of EmimOs and DAH because of their comparatively smaller alkyl (octyl and hexanoate) chain. However, the direction of C-343 migration is reversed with the decrease of pH of the SB-16 micellar medium. An increase in the average solvation and rotational relaxation time of the probe in acidic medium has been observed. Since experimental conditions are maintained such that the probe molecules and the zwitterionic SB-16 micelles remain oppositely charged, the observed results can be attributed to the increased electrostatic interaction (attractive) between them. Temperature dependent study also supports this finding.

Modeling the Coupled Chemo-Thermo-Mechanical Behavior of Amorphous Polymer Networks.

Energy Technology Data Exchange (ETDEWEB)

Zimmerman, Jonathan A. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Nguyen, Thao D. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Xiao, Rui [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

2015-02-01

Amorphous polymers exhibit a rich landscape of time-dependent behavior including viscoelasticity, structural relaxation, and viscoplasticity. These time-dependent mechanisms can be exploited to achieve shape-memory behavior, which allows the material to store a programmed deformed shape indefinitely and to recover entirely the undeformed shape in response to specific environmental stimulus. The shape-memory performance of amorphous polymers depends on the coordination of multiple physical mechanisms, and considerable opportunities exist to tailor the polymer structure and shape-memory programming procedure to achieve the desired performance. The goal of this project was to use a combination of theoretical, numerical and experimental methods to investigate the effect of shape memory programming, thermo-mechanical properties, and physical and environmental aging on the shape memory performance. Physical and environmental aging occurs during storage and through exposure to solvents, such as water, and can significantly alter the viscoelastic behavior and shape memory behavior of amorphous polymers. This project – executed primarily by Professor Thao Nguyen and Graduate Student Rui Xiao at Johns Hopkins University in support of a DOE/NNSA Presidential Early Career Award in Science and Engineering (PECASE) – developed a theoretical framework for chemothermo- mechanical behavior of amorphous polymers to model the effects of physical aging and solvent-induced environmental factors on their thermoviscoelastic behavior.

Nanoscale isoindigo-carriers: self-assembly and tunable properties

Directory of Open Access Journals (Sweden)

Tatiana N. Pashirova

2017-02-01

Full Text Available Over the last decade isoindigo derivatives have attracted much attention due to their high potential in pharmacy and in the chemistry of materials. In addition, isoindigo derivatives can be modified to form supramolecular structures with tunable morphologies for the use in drug delivery. Amphiphilic long-chain dialkylated isoindigos have the ability to form stable solid nanoparticles via a simple nanoprecipitation technique. Their self-assembly was investigated using tensiometry, dynamic light scattering, spectrophotometry, and fluorometry. The critical association concentrations and aggregate sizes were measured. The hydrophilic–lipophilic balance of alkylated isoindigo derivatives strongly influences aggregate morphology. In the case of short-chain dialkylated isoindigo derivatives, supramolecular polymers of 200 to 700 nm were formed. For long-chain dialkylated isoindigo derivatives, micellar aggregates of 100 to 200 nm were observed. Using micellar surfactant water-soluble forms of monosubstituted 1-hexadecylisoindigo as well as 1,1′-dimethylisoindigo were prepared for the first time. The formation of mixed micellar structures of different types in micellar anionic surfactant solutions (sodium dodecyl sulfate was determined. These findings are of practical importance and are of potential interest for the design of drug delivery systems and new nanomaterials.

NCAP projection displays: key issues for commercialization

Science.gov (United States)

Tomita, Akira; Jones, Philip J.

1992-06-01

Recently there has been much interest in a new polymer nematic dispersion technology, often called as NCAP, PDLC, PNLC, LCPC, etc., since projection displays using this technology have been shown to produce much brighter display images than projectors using conventional twisted nematic (TN) lightvalves. For commercializing projection displays based on this polymer nematic dispersion technology, the new materials must not only meet various electro- optic requirements, e.g., operational voltage, `off-state'' scattering angle, voltage holding ratio and hysteresis, but must also be stable over the lifetime of the product. This paper reports recent progress in the development of NCAP based projection displays and discusses some of the key commercialization issues.

A new application of micellar liquid chromatography in the determination of free ampicillin concentration in the drug-human serum albumin standard solution in comparison with the adsorption method.

Science.gov (United States)

Stępnik, Katarzyna E; Malinowska, Irena; Maciejewska, Małgorzata

2016-06-01

The determination of free drug concentration is a very important issue in the field of pharmacology because only the unbound drug fraction can achieve a pharmacological effect. Due to the ability to solubilize many different compounds in micellar aggregates, micellar liquid chromatography (MLC) can be used for direct determination of free drug concentration. Proteins are not retained on the stationary phase probably due to the formation of protein - surfactant complexes which are excluded from the pores of stationary phase. The micellar method is simple and fast. It does not require any pre-preparation of the tested samples for analysis. The main aim of this paper is to demonstrate a completely new applicability of the analytical use of MLC concerning the determination of free drug concentration in the standard solution of human serum albumin. The well-known adsorption method using RP-HPLC and the spectrophotometric technique was applied as the reference method. The results show that the free drug concentration value obtained in the MLC system (based on the RP-8 stationary phase and CTAB) is similar to that obtained by the adsorption method: both RP-HPLC (95.83μgmL(-1), 79.86% of free form) and spectrophotometry (95.71μgmL(-1), 79.76%). In the MLC the free drug concentration was 93.98μgmL(-1) (78.3%). This indicates that the obtained results are within the analytical range of % of free ampicillin fraction and the MLC with direct sample injection can be treated like a promising method for the determination of free drug concentration. Copyright © 2016 Elsevier B.V. All rights reserved.

Simultaneous Determination of Eosin-Yellow and Ponceau-S Using H-Point Standard Addition Method in Micellar Media

Directory of Open Access Journals (Sweden)

Amandeep Kaur

2012-01-01

Full Text Available H-point standard addition method (HPSAM is developed for simultaneous determination of eosin-Y and ponceau-s in micellar media. Nickel chloride (NiCl2 is used as chromogenic reagent for complexes formation of eosin-Y and ponceau-S food colorants. The measurements were carried out using sodium lauryl sulphate as a surfactant, in buffered solution at pH 6.0. The concentration range of 0.115-2.53 μg/mL of eosin-Y and 0.159-3.80 μg/mL of ponceau-S. The proposed procedures have been applied successfully for the simultaneous determination of eosin-Y and ponceau-S in synthetic binary mixtures and real samples.

Topographic characterization of nanostructures on curved polymer surfaces

DEFF Research Database (Denmark)

Feidenhans'l, Nikolaj Agentoft; Petersen, Jan C.; Taboryski, Rafael J.

2014-01-01

The availability of portable instrumentation for characterizing surface topography on the micro- and nanometer scale is very limited. Particular the handling of curved surfaces, both concave and convex, is complicated or not possible on current instrumentation. However, the currently growing use...... method with a portable instrument that can be used in a production environment, and topographically characterize nanometer-scale surface structures on both flat and curved surfaces. To facilitate the commercialization of injection moulded polymer parts featuring nanostructures, it is pivotal...... of injection moulding of polymer parts featuring nanostructured surfaces, requires an instrument that can characterize these structures to ensure replication-confidence between master structure and replicated polymer parts. This project concerns the development of a metrological traceable quality control...

Water-soluble chelating polymers for removal of actinides from wastewater

International Nuclear Information System (INIS)

Jarvinen, G.D.

1997-01-01

Polymer filtration is a technology under development to selectively recover valuable or regulated metal ions from process or wastewaters. The technology uses water-soluble chelating polymers that are designed to selectively bind with metal ions in aqueous solutions. The polymers have a sufficiently large molecular weight that they can be separated and concentrated using available ultrafiltration (UF) technology. The UF range is generally considered to include molecular weights from about 3000 to several million daltons and particles sizes of about 2 to 1000 nm. Water and smaller unbound components of the solution pass freely through the UF membrane. The polymers can then be reused by changing the solution conditions to release the metal ions that are recovered in concentrated form for recycle or disposal. Some of the advantages of polymer filtration relative to technology now in use are rapid binding kinetics, high selectivity, low energy and capital costs, and a small equipment footprint. Some potential commercial applications include electroplating rinse waters, photographic processing, nuclear power plant cooling water; remediation of contaminated soils and groundwater; removal of mercury contamination; and textile, paint and dye production. The purpose of this project is to evaluate this technology to remove plutonium, americium, and other regulated metal ions from various process and waste streams found in nuclear facilities. The work involves preparation of the water-soluble chelating polymers; small-scale testing of the chelating polymer systems for the required solubility, UF properties, selectivity and binding constants; followed by an engineering assessment at a larger scale to allow comparison to competing separation technologies. This project focuses on metal-ion contaminants in waste streams at the Plutonium Facility and the Waste Treatment Facility at LANL. Potential applications at other DOE facilities are also apparent

Water-soluble chelating polymers for removal of actinides from wastewater

Energy Technology Data Exchange (ETDEWEB)

Jarvinen, G.D. [Los Alamos National Lab., NM (United States)

1997-10-01

Polymer filtration is a technology under development to selectively recover valuable or regulated metal ions from process or wastewaters. The technology uses water-soluble chelating polymers that are designed to selectively bind with metal ions in aqueous solutions. The polymers have a sufficiently large molecular weight that they can be separated and concentrated using available ultrafiltration (UF) technology. The UF range is generally considered to include molecular weights from about 3000 to several million daltons and particles sizes of about 2 to 1000 nm. Water and smaller unbound components of the solution pass freely through the UF membrane. The polymers can then be reused by changing the solution conditions to release the metal ions that are recovered in concentrated form for recycle or disposal. Some of the advantages of polymer filtration relative to technology now in use are rapid binding kinetics, high selectivity, low energy and capital costs, and a small equipment footprint. Some potential commercial applications include electroplating rinse waters, photographic processing, nuclear power plant cooling water; remediation of contaminated soils and groundwater; removal of mercury contamination; and textile, paint and dye production. The purpose of this project is to evaluate this technology to remove plutonium, americium, and other regulated metal ions from various process and waste streams found in nuclear facilities. The work involves preparation of the water-soluble chelating polymers; small-scale testing of the chelating polymer systems for the required solubility, UF properties, selectivity and binding constants; followed by an engineering assessment at a larger scale to allow comparison to competing separation technologies. This project focuses on metal-ion contaminants in waste streams at the Plutonium Facility and the Waste Treatment Facility at LANL. Potential applications at other DOE facilities are also apparent.

Importance of critical micellar concentration for the prediction of solubility enhancement in biorelevant media.

Science.gov (United States)

Ottaviani, G; Wendelspiess, S; Alvarez-Sánchez, R

2015-04-06

This study evaluated if the intrinsic surface properties of compounds are related to the solubility enhancement (SE) typically observed in biorelevant media like fasted state simulated intestinal fluids (FaSSIF). The solubility of 51 chemically diverse compounds was measured in FaSSIF and in phosphate buffer and the surface activity parameters were determined. This study showed that the compound critical micellar concentration parameter (CMC) correlates strongly with the solubility enhancement (SE) observed in FaSSIF compared to phosphate buffer. Thus, the intrinsic capacity of molecules to form micelles is also a determinant for each compound's affinity to the micelles of biorelevant surfactants. CMC correlated better with SE than lipophilicity (logD), especially over the logD range typically covered by drugs (2 < logD < 4). CMC can become useful to guide drug discovery scientists to better diagnose, improve, and predict solubility in biorelevant media, thereby enhancing oral bioavailability of drug candidates.

Funnel-type etched ion tracks in polymers

Czech Academy of Sciences Publication Activity Database

Fink, Dietmar; Vacík, Jiří; Hnatowicz, Vladimír; Munoz, G. H.; Alfonta, L.; Klinkovich, I.

2010-01-01

Roč. 165, č. 5 (2010), s. 343-361 ISSN 1042-0150 R&D Projects: GA AV ČR(CZ) KAN400480701 Institutional research plan: CEZ:AV0Z10480505 Keywords : tracks * polymers * etching Subject RIV: JJ - Other Materials Impact factor: 0.660, year: 2010

Liquid-liquid extraction and separation of VIII group elements, especially ruthenium, by synergic combinations or aromatic polyimines and micellar cationic exchangers

International Nuclear Information System (INIS)

Vitart, X.

1991-01-01

This thesis aims to characterize and to quantify the chemical equilibria involved in d-elements liquid-liquid extraction systems, especially elements belonging to the VIII group (Fe, Ni, Co, Ru, Rh, Pd, Pt). These systems are composed of synergic combination of aromatic polyimines and micellar cationic exchangers. Substitutions are first performed in aqueous acidic media by aromatic polyimines; then extractions are operated using micellic canionic exchangers. Chemical equilibria, selectivity effects, especially those due to ion-pair formations, kinetics, extractant behaviour are analysed and quantified [fr

Magnetic field processing of inorganic polymers

Energy Technology Data Exchange (ETDEWEB)

Kunerth, D.C.; Peterson, E.S. [Idaho National Engineering Laboratory, Idaho Falls, ID (United States)

1995-05-01

The purpose of this project is to investigate, understand, and demonstrate the use of magnetic field processing (MFP) to modify the properties of inorganic-based polymers and to develop the basic technical knowledge required for industrial implementation. Polyphosphazene membranes for chemical separation applications are being emphasized by this project. Previous work demonstrated that magnetic fields, appropriately applied during processing, can be used to beneficially modify membrane morphology. MFP membranes have significantly increased flux capabilities while maintaining the same chemical selectivity as the unprocessed membranes.

A review on development of analytical methods to determine monitorable drugs in serum and urine by micellar liquid chromatography using direct injection.

Science.gov (United States)

Esteve-Romero, Josep; Albiol-Chiva, Jaume; Peris-Vicente, Juan

2016-07-05

Therapeutic drug monitoring is a common practice in clinical studies. It requires the quantification of drugs in biological fluids. Micellar liquid chromatography (MLC), a well-established branch of Reverse Phase-High Performance Liquid Chromatography (RP-HPLC), has been proven by many researchers as a useful tool for the analysis of these matrices. This review presents several analytical methods, taken from the literature, devoted to the determination of several monitorable drugs in serum and urine by micellar liquid chromatography. The studied groups are: anticonvulsants, antiarrhythmics, tricyclic antidepressants, selective serotonin reuptake inhibitors, analgesics and bronchodilators. We detail the optimization strategy of the sample preparation and the main chromatographic conditions, such as the type of column, mobile phase composition (surfactant, organic solvent and pH), and detection. The finally selected experimental parameters, the validation, and some applications have also been described. In addition, their performances and advantages have been discussed. The main ones were the possibility of direct injection, and the efficient chromatographic elution, in spite of the complexity of the biological fluids. For each substance, the measured concentrations were accurate and precise at their respective therapeutic range. It was found that the MLC-procedures are fast, simple, inexpensive, ecofriendly, safe, selective, enough sensitive and reliable. Therefore, they represent an excellent alternative for the determination of drugs in serum and urine for monitoring purposes. Copyright © 2016 Elsevier B.V. All rights reserved.

Chelating water-soluble polymers for waste minimization

International Nuclear Information System (INIS)

Smith, B.; Cournoyer, M.; Duran, B.; Ford, D.; Gibson, R.; Lin, M.; Meck, A.; Robinson, P.; Robison, T.

1996-01-01

Within the DOE complex and in industry there is a tremendous need for advanced metal ion recovery and waste minimization techniques. This project sought to employ capabilities for ligand-design and separations chemistry in which one can develop and evaluate water- soluble chelating polymers for recovering actinides and toxic metals from various process streams. Focus of this work was (1) to develop and select a set of water-soluble polymers suitable for a selected waste stream and (2) demonstrate this technology in 2 areas: removal of (a) actinides and toxic RCRA metals from waste water and (b) recovery of Cu and other precious metals from industrial process streams including from solid catalysts and aqueous waste streams. The R ampersand D was done in 4 phases for each of the 2 target areas: polymer synthesis for scaleup, equipment assembly, process demonstration at a DOE or industrial site, and advanced ligand/polymer synthesis. The TA- 50 site at Los Alamos was thought to be appropriate due to logistics and to its being representative of similar problems throughout the DOE complex

Star-Branched Polymers (Star Polymers)

KAUST Repository

Hirao, Akira

2015-09-01

The synthesis of well-defined regular and asymmetric mixed arm (hereinafter miktoarm) star-branched polymers by the living anionic polymerization is reviewed in this chapter. In particular, much attention is being devoted to the synthetic development of miktoarm star polymers since 2000. At the present time, the almost all types of multiarmed and multicomponent miktoarm star polymers have become feasible by using recently developed iterative strategy. For example, the following well-defined stars have been successfully synthesized: 3-arm ABC, 4-arm ABCD, 5-arm ABCDE, 6-arm ABCDEF, 7-arm ABCDEFG, 6-arm ABC, 9-arm ABC, 12-arm ABC, 13-arm ABCD, 9-arm AB, 17-arm AB, 33-arm AB, 7-arm ABC, 15-arm ABCD, and 31-arm ABCDE miktoarm star polymers, most of which are quite new and difficult to synthesize by the end of the 1990s. Several new specialty functional star polymers composed of vinyl polymer segments and rigid rodlike poly(acetylene) arms, helical polypeptide, or helical poly(hexyl isocyanate) arms are introduced.

Radiation processing of natural polymers: The IAEA contribution

Science.gov (United States)

Haji-Saeid, Mohammad; Safrany, Agnes; Sampa, Maria Helena de O.; Ramamoorthy, Natesan

2010-03-01

Radiation processing offers a clean and additive-free method for preparation of value-added novel materials based on renewable, non-toxic, and biodegradable natural polymers. Crosslinked natural polymers can be used as hydrogel wound dressings, face cleaning cosmetic masks, adsorbents of toxins, and non-bedsore mats; while low molecular weight products show antibiotic, antioxidant, and plant-growth promoting properties. Recognizing the potential benefits that radiation technology can offer for processing of natural polymers into useful products, the IAEA implemented a coordinated research project (CRP) on "Development of Radiation-processed products of Natural Polymers for application in Agriculture, Healthcare, Industry and Environment". This CRP was launched at the end of 2007 with participation of 16 MS to help connecting radiation technology and end-users to derive enhanced benefits from these new value-added products of radiation-processed natural materials. In this paper the results of activities in participating MS related to this work will be presented.

Radiation processing of natural polymers: The IAEA contribution

International Nuclear Information System (INIS)

Haji-Saeid, Mohammad; Safrany, Agnes; Sampa, Maria Helena de O.; Ramamoorthy, Natesan

2010-01-01

Radiation processing offers a clean and additive-free method for preparation of value-added novel materials based on renewable, non-toxic, and biodegradable natural polymers. Crosslinked natural polymers can be used as hydrogel wound dressings, face cleaning cosmetic masks, adsorbents of toxins, and non-bedsore mats; while low molecular weight products show antibiotic, antioxidant, and plant-growth promoting properties. Recognizing the potential benefits that radiation technology can offer for processing of natural polymers into useful products, the IAEA implemented a coordinated research project (CRP) on 'Development of Radiation-processed products of Natural Polymers for application in Agriculture, Healthcare, Industry and Environment'. This CRP was launched at the end of 2007 with participation of 16 MS to help connecting radiation technology and end-users to derive enhanced benefits from these new value-added products of radiation-processed natural materials. In this paper the results of activities in participating MS related to this work will be presented.

Polymer nanocomposites: polymer and particle dynamics

KAUST Repository

Kim, Daniel; Srivastava, Samanvaya; Narayanan, Suresh; Archer, Lynden A.

2012-01-01

Polymer nanocomposites containing nanoparticles smaller than the random coil size of their host polymer chains are known to exhibit unique properties, such as lower viscosity and glass transition temperature relative to the neat polymer melt. It has

Production efficiency of micellar casein concentrate using polymeric spiral-wound microfiltration membranes.

Science.gov (United States)

Beckman, S L; Zulewska, J; Newbold, M; Barbano, D M

2010-10-01

Most current research has focused on using ceramic microfiltration (MF) membranes for micellar casein concentrate production, but little research has focused on the use of polymeric spiral-wound (SW) MF membranes. A method for the production of a serum protein (SP)-reduced micellar casein concentrate using SW MF was compared with a ceramic MF membrane. Pasteurized (79°C, 18s) skim milk (1,100 kg) was microfiltered at 50°C [about 3 × concentration] using a 0.3-μm polyvinylidene fluoride spiral-wound membrane, bleed-and-feed, 3-stage process, using 2 diafiltration stages, where the retentate was diluted 1:2 with reverse osmosis water. Skim milk, permeate, and retentate were analyzed for SP content, and the reduction of SP from skim milk was determined. Theoretically, 68% of the SP content of skim milk can be removed using a single-stage 3× MF. If 2 subsequent water diafiltration stages are used, an additional 22% and 7% of the SP can be removed, respectively, giving a total SP removal of 97%. Removal of SP greater than 95% has been achieved using a 0.1-μm pore size ceramic uniform transmembrane pressure (UTP) MF membrane after a 3-stage MF with diafiltration process. One stage of MF plus 2 stages of diafiltration of 50°C skim milk using a polyvinylidene fluoride polymeric SW 0.3-μm membrane yielded a total SP reduction of only 70.3% (stages 1, 2, and 3: 38.6, 20.8, and 10.9%, respectively). The SP removal rate for the polymeric SW MF membrane was lower in all 3 stages of processing (stages 1, 2, and 3: 0.05, 0.04, and 0.03 kg/m(2) per hour, respectively) than that of the comparable ceramic UTP MF membrane (stages 1, 2, and 3: 0.30, 0.11, and 0.06 kg/m(2) per hour, respectively), indicating that SW MF is less efficient at removing SP from 50°C skim milk than the ceramic UTP system. To estimate the number of steps required for the SW system to reach 95% SP removal, the third-stage SP removal rate (27.4% of the starting material SP content) was used to

Demonstration of Thermally Sprayed Metal and Polymer Coatings for Steel Structures at Fort Bragg, NC

Science.gov (United States)

2017-09-01

ER D C/ CE RL T R- 17 -3 0 DoD Corrosion Prevention and Control Program Demonstration of Thermally Sprayed Metal and Polymer Coatings...and Polymer Coatings for Steel Structures at Fort Bragg, NC Final Report on Project F07-AR10 Larry D. Stephenson, Alfred D. Beitelman, Richard G...5 2.1.2 Thermoplastic polymer coating (flame spray

Electroluminescence of Multicomponent Conjugated Polymers. 1. Roles of Polymer/Polymer Interfaces in Emission Enhancement and Voltage-Tunable Multicolor Emission in Semiconducting Polymer/Polymer Heterojunctions

National Research Council Canada - National Science Library

Zhang, Xuejun, Ph.D

1999-01-01

Effects of the electronic structure of polymer/polymer interfaces on the electroluminescence efficiency and tunable multicolor emission of polymer heterojunction light-emitting diodes were explored...

Fabrication of Micrometer- and Nanometer-Scale Polymer Structures by Visible Light Induced Dielectrophoresis (DEP Force

Directory of Open Access Journals (Sweden)

Wen J. Li

2011-12-01

Full Text Available We report in this paper a novel, inexpensive and flexible method for fabricating micrometer- and nanometer-scale three-dimensional (3D polymer structures using visible light sources instead of ultra-violet (UV light sources or lasers. This method also does not require the conventional micro-photolithographic technique (i.e., photolithographic masks for patterning and fabricating polymer structures such as hydrogels. The major materials and methods required for this novel fabrication technology are: (1 any cross-linked network of photoactive polymers (examples of fabricated poly(ethylene glycol (PEG-diacrylate hydrogel structures are shown in this paper; (2 an Optically-induced Dielectrophoresis (ODEP System which includes an “ODEP chip” (i.e., any chip that changes its surface conductivity when exposed to visible light, an optical microscope, a projector, and a computer; and (3 an animator software hosted on a computer that can generate virtual or dynamic patterns which can be projected onto the “ODEP chip” through the use of a projector and a condenser lens. Essentially, by placing a photosensitive polymer solution inside the microfluidic platform formed by the “ODEP chip” bonded to another substrate, and applying an alternating current (a.c. electrical potential across the polymer solution (typically ~20 Vp-p at 10 kHz, solid polymer micro/nano structures can then be formed on the “ODEP chip” surface when visible-light is projected onto the chip. The 2D lateral geometry (x and y dimensions and the thickness (height of the micro/nano structures are dictated by the image geometry of the visible light projected onto the “ODEP chip” and also the time duration of projection. Typically, after an image projection with intensity ranging from ~0.2 to 0.4 mW/cm2 for 10 s, ~200 nm high structures can be formed. In our current system, the thickness of these polymer structures can be controlled to form from ~200 nanometers to ~3

3D optical printing of piezoelectric nanoparticle-polymer composite materials.

Science.gov (United States)

Kim, Kanguk; Zhu, Wei; Qu, Xin; Aaronson, Chase; McCall, William R; Chen, Shaochen; Sirbuly, Donald J

2014-10-28

Here we demonstrate that efficient piezoelectric nanoparticle-polymer composite materials can be optically printed into three-dimensional (3D) microstructures using digital projection printing. Piezoelectric polymers were fabricated by incorporating barium titanate (BaTiO3, BTO) nanoparticles into photoliable polymer solutions such as polyethylene glycol diacrylate and exposing to digital optical masks that could be dynamically altered to generate user-defined 3D microstructures. To enhance the mechanical-to-electrical conversion efficiency of the composites, the BTO nanoparticles were chemically modified with acrylate surface groups, which formed direct covalent linkages with the polymer matrix under light exposure. The composites with a 10% mass loading of the chemically modified BTO nanoparticles showed piezoelectric coefficients (d(33)) of ∼ 40 pC/N, which were over 10 times larger than composites synthesized with unmodified BTO nanoparticles and over 2 times larger than composites containing unmodified BTO nanoparticles and carbon nanotubes to boost mechanical stress transfer efficiencies. These results not only provide a tool for fabricating 3D piezoelectric polymers but lay the groundwork for creating highly efficient piezoelectric polymer materials via nanointerfacial tuning.

Progress of the BT-EdF-CEA project. The lithium polymer battery; Avancees du projet BT-EdF-CEA. Batterie lithium polymere

Energy Technology Data Exchange (ETDEWEB)

Marginedes, D.; Majastre, H. [Bollore Technologies, 29 - Quimper (France); Baudry, P.; Lascaud, S. [Electricite de France, 77 - Moret sur Loing (France). Direction des Etudes et Recherches; Bloch, D.; Lebrun, N. [CEA Grenoble, CEREM, 38 (France)

1996-12-31

The lithium-polymer energy storage technology requires the production of thin films of huge surface. The BT-EdF-CEA consortium has studied the various manufacturing techniques of these films and their assembly. The process was chosen according to its productivity, low expensiveness, ecological impact and energy performances with capacities reaching 40 Ah. This paper explains: the objectives and specifications of the project, the advantage of the consortium and the role of the different partners, the results (coating, dry extrusion and battery element manufacturing techniques), and the electrochemical performances of the elements. (J.S.)

Progress of the BT-EdF-CEA project. The lithium polymer battery; Avancees du projet BT-EdF-CEA. Batterie lithium polymere

Energy Technology Data Exchange (ETDEWEB)

Marginedes, D; Majastre, H [Bollore Technologies, 29 - Quimper (France); Baudry, P; Lascaud, S [Electricite de France, 77 - Moret sur Loing (France). Direction des Etudes et Recherches; Bloch, D; Lebrun, N [CEA Grenoble, CEREM, 38 (France)

1997-12-31

The lithium-polymer energy storage technology requires the production of thin films of huge surface. The BT-EdF-CEA consortium has studied the various manufacturing techniques of these films and their assembly. The process was chosen according to its productivity, low expensiveness, ecological impact and energy performances with capacities reaching 40 Ah. This paper explains: the objectives and specifications of the project, the advantage of the consortium and the role of the different partners, the results (coating, dry extrusion and battery element manufacturing techniques), and the electrochemical performances of the elements. (J.S.)

Determination of water-soluble vitamins in multivitamin dietary supplements and in artichokes by micellar electrokinetic chromatography.

Science.gov (United States)

Serni, Enrico; Audino, Valeria; Del Carlo, Sara; Manera, Clementina; Saccomanni, Giuseppe; Macchia, Marco

2013-01-01

Several procedures of extraction with solvents for the simultaneous determination of vitamin C and some vitamins belonging to the B group (thiamine, riboflavine, nicotinic acid and nicotinamide) in multivitamin preparations and in artichokes (Cynara cardunculus subsp. scolymus [L.] Hegi) were developed. Different experimental conditions were used, in terms of heat treatment, composition and pH of the extraction mixture, with particular attention to high-temperature steps; purification of the extracts with solid phase extraction and stabilisation through lyophilisation were discussed. Analyses of the extracts were conducted by capillary electrophoresis in micellar electrokinetic chromatography modality. Borate buffer at pH 8.2 was used, and sodium dodecyl sulphate was added to the background electrolyte as surfactant. A range of linearity was determined and calibration curves were plotted for all the analytes.

Polymer electronics

CERN Document Server

Hsin-Fei, Meng

2013-01-01

Polymer semiconductor is the only semiconductor that can be processed in solution. Electronics made by these flexible materials have many advantages such as large-area solution process, low cost, and high performance. Researchers and companies are increasingly dedicating time and money in polymer electronics. This book focuses on the fundamental materials and device physics of polymer electronics. It describes polymer light-emitting diodes, polymer field-effect transistors, organic vertical transistors, polymer solar cells, and many applications based on polymer electronics. The book also disc

Biodegradable Polymers

OpenAIRE

Vroman, Isabelle; Tighzert, Lan

2009-01-01

Biodegradable materials are used in packaging, agriculture, medicine and other areas. In recent years there has been an increase in interest in biodegradable polymers. Two classes of biodegradable polymers can be distinguished: synthetic or natural polymers. There are polymers produced from feedstocks derived either from petroleum resources (non renewable resources) or from biological resources (renewable resources). In general natural polymers offer fewer advantages than synthetic polymers. ...

PH-triggered micellar membrane for controlled release microchips

KAUST Repository

Yang, Xiaoqiang; Moosa, Basem; Deng, Lin; Zhao, Lan; Khashab, Niveen M.

2011-01-01

A pH-responsive membrane based on polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) block copolymer was developed on a model glass microchip as a promising controlled polymer delivery system. The PS-b-P4VP copolymer assembles into spherical and

Polymer Crowding in Confined Polymer-Nanoparticle Mixtures

Science.gov (United States)

Davis, Wyatt J.; Denton, Alan R.

Crowding can influence the conformations and thus functionality of macromolecules in quasi-two-dimensional environments, such as DNA or proteins confined to a cell membrane. We explore such crowding within a model of polymers as penetrable ellipses, whose shapes are governed by the statistics of a 2D random walk. The principal radii of the polymers fluctuate according to probability distributions of the eigenvalues of the gyration tensor. Within this coarse-grained model, we perform Monte Carlo simulations of mixtures of polymers and hard nanodisks, including trial changes in polymer conformation (shape and orientation). Penetration of polymers by nanodisks is incorporated with a free energy cost predicted by polymer field theory. Over ranges of size ratio and nanodisk density, we analyze the influence of crowding on polymer shape by computing eigenvalue distributions, mean radius of gyration, and mean asphericity of the polymer. We compare results with predictions of free-volume theory and with corresponding results in three dimensions. Our approach may help to interpret recent (and motivate future) experimental studies of biopolymers interacting with cell membranes, with relevance for drug delivery and gene therapy. This work was supported by the National Science Foundation under Grant No. DMR-1106331.

Development of polymer hybrid materials and analyzing techniques for their depletions

International Nuclear Information System (INIS)

Takaya, Haruo; Kobayashi, Yoshinori; Hirata, Koichi; Nakahara, Hisae; Kinugasa, Shinichi; Kamiya, Yoshinori

1999-01-01

The purpose of this research project was to develop new methods for evaluation and analysis of deterioration of polymer materials under radiological environment and its complicated environment including chemical effects. Furthermore, a screening and development for new radio-resistant polymer materials were attempted. In 1996, the third year of this project, the effects of γ-ray exposure on cardo-type polymers, novel high performance molecules were investigated and the early radiochemical changes due to the exposure were studied according to measurement of the life-time of cation. Cardo-type polymers were exposed to γ-ray and the changes in the molecular size and its distribution were analyzed by size exclusion chromatography and multi-angle laser light scattering (SEC/MALLS). Two cardo-type polymers, PI-BP and PA-T were used as the test subjects and polystyrene was as the standard control. Three membranes made from these three polymers were exposed to γ-ray at 0.2-1.2 MGy. The exposed membranes were applied onto SEC/MALLS after dissolving in NMP. The molecular weight of PI-BP was decreased as an increase of the radiation dose and there appeared a peak in a low molecular range when exposed at higher than 0.4 MGy. The molecular weight was decreased depending to the dose for all of the two cardo-type polymers and the control polystyrene sample. The ratio, Mw/Mn for PI-BP was decreased as an increase of the dose, whereas the ratio for PA-T was hardly changed by the exposure. On the contrary, the ratio for the polystyrene sample was greatly changed as an increase of the dose. These results suggest that various molecular-sized chains were produced by the exposure from the molecule, of which size was mono-dispersed before the exposure. (M.N.)

Discrepancies over the onset of surfactant monomer aggregation interpreted by fluorescence, conductivity and surface tension methods

Directory of Open Access Journals (Sweden)

Maria de Fátima Carvalho Costa

1998-06-01

Full Text Available Molecular probe techniques have made important contributions to the determination of microstructure of surfactant assemblies such as size, stability, micropolarity and conformation. Conductivity and surface tension were used to determine the critical aggregation concentration (cac of polymer-surfactant complexes and the critical micellar concentration (cmc of aqueous micellar aggregates. The results are compared with those of fluorescent techniques. Several surfactant systems were examined, 1-butanol-sodium dodecylsulfate (SDS mixtures, solutions containing poly(ethylene oxide-SDS, poly(vinylpyrrolidone-SDS and poly(acrylic acid-alkyltrimethylammonium bromide complexes. We found differences between the cac and cmc values obtained by conductivity or surface tension and those obtained by techniques which use hydrophobic probe.

Thermosetting microemulsions and mixed micellar solutions as drug delivery systems for periodontal anesthesia.

Science.gov (United States)

Scherlund, M; Malmsten, M; Holmqvist, P; Brodin, A

2000-01-20

In the present study, thermosetting microemulsions and mixed micellar solutions were investigated as drug delivery systems for anesthetizing the periodontal pocket. The structure of the systems, consisting of the active ingredients lidocaine and prilocaine, as well as two block copolymers (Lutrol F127 and Lutrol F68), was investigated by NMR spectroscopy and photon correlation spectroscopy (PCS). The results obtained for dilute (1-3% w/w) solutions show discrete micelles with a diameter of 20-30 nm and a critical micellization temperature of 25-35 degrees C. Gel permeation chromatography (GPC) was used to study the distribution of the active ingredients, and indicates a preferential solubilization of the active components in micelles over unimers. Analogous to the Lutrol F127 single component system these formulations display an abrupt gelation on increasing temperature. The gelation temperature was found to depend on both the drug ionization and concentration. These systems have several advantages over emulsion-based formulations including good stability, ease of preparation, increased drug release rate, and improved handling due to the transparency of the formulations.

Diamond structures grown from polymer composite nanofibers

Czech Academy of Sciences Publication Activity Database

Potocký, Štěpán; Kromka, Alexander; Babchenko, Oleg; Rezek, Bohuslav; Martinová, L.; Pokorný, P.

2013-01-01

Roč. 5, č. 6 (2013), s. 519-521 ISSN 2164-6627 R&D Projects: GA ČR GAP108/12/0910; GA ČR GAP205/12/0908 Institutional support: RVO:68378271 Keywords : chemical vapour deposition * composite polymer * nanocrystalline diamond * nanofiber sheet * SEM Subject RIV: BM - Solid Matter Physics ; Magnetism

Understanding Molecular Interactions within Chemically Selective Layered Polymer Assemblies

Energy Technology Data Exchange (ETDEWEB)

Gary J. Blanchard

2009-06-30

This work focuses on two broad issues. These are (1) the molecular origin of the chemical selectivity achieved with ultrathin polymer multilayers, and (2) how the viscoelastic properties of the polymer layers are affected by exposure to solvent and analytes. These issues are inter-related, and to understand them we need to design experiments that probe both the energetic and kinetic aspects of interfacial adsorption processes. This project focuses on controling the chemical structure, thickness, morphology and sequential ordering of polymer layers bound to interfaces using maleimide-vinyl ether and closely related alternating copolymerization chemistry and efficient covalent cross-linking reactions that allow for layer-by-layer polymer deposition. This chemistry has been developed during the funding cycle of this Grant. We have measure the equilibrium constants for interactions between specific layers within the polymer interfaces and size-controlled, surface-functionalized gold nanoparticles. The ability to control both size and functionality of gold nanoparticle model analytes allows us to evaluate the average “pore size” that characterizes our polymer films. We have measured the “bulk” viscosity and shear modulus of the ultrathin polymer films as a function of solvent overlayer identity using quartz crystal microbalance complex impedance measurements. We have measured microscopic viscosity at specific locations within the layered polymer interfaces with time-resolved fluorescence lifetime and depolarization techniques. We combine polymer, cross-linking and nanoparticle synthetic expertise with a host of characterization techniques, including QCM gravimetry and complex impedance analysis, steady state and time-resolved spectroscopies.

Determination of Sodium deoxycolate residues in vaccinal formulation by micellar electrokinetic chromatography

International Nuclear Information System (INIS)

Merchan, Yaima; Lucangioli, Silvia; Carducci, Clyde

2011-01-01

The sodium deoxycholate (DCNa) source is the surfactant used in the biopharmaceutical industry for the solubilization of outer membrane vesicles. It is well known the importance of control of this metabolite in biological materials due to its high toxicity for humans. To demonstrate significant small variations of this metabolite in vaccine formulations it is necessary to use a methodology highly selective, sensitive, specific and reproducible. In this report we used the micellar electrokinetic chromatography (MEKC) in a Capillary Ion Analyzer (Water corp. Milford MA) detection at 185 nm mercury lamp. It employed a fused silica capillary uncoated (Waters Corp. Milford MA). We assessed the purity of 2 lots of sodium deoxycholate and analyzed 15 samples of purified vesicles active pharmaceutical ingredient vaccine formulations. Data were recorded and processed with software Millennium TM (Waters Corp. Milford MA). It was found that lots of sodium deoxycholate containing 1.19 and 0.44% cholic acid and contaminate that 93% of the purified vesicles samples were from 0 to 2.44 mg protein DCNa/100 μg. MECK's results were compared with a kinetic test used to determine bile acids in blood (Merckotest). MECK system showed better results regarding the Merkotest

Investigation of polymer derived ceramics cantilevers for application of high speed atomic force microscopy

Science.gov (United States)

Wu, Chia-Yun

High speed Atomic Force Microscopy (AFM) has a wide variety of applications ranging from nanomanufacturing to biophysics. In order to have higher scanning speed of certain AFM modes, high resonant frequency cantilevers are needed; therefore, the goal of this research is to investigate using polymer derived ceramics for possible applications in making high resonant frequency AFM cantilevers using complex cross sections. The polymer derived ceramic that will be studied, is silicon carbide. Polymer derived ceramics offer a potentially more economic fabrication approach for MEMS due to their relatively low processing temperatures and ease of complex shape design. Photolithography was used to make the desired cantilever shapes with micron scale size followed by a wet etching process to release the cantilevers from the substrates. The whole manufacturing process we use borrow well-developed techniques from the semiconducting industry, and as such this project also could offer the opportunity to reduce the fabrication cost of AFM cantilevers and MEMS in general. The characteristics of silicon carbide made from the precursor polymer, SMP-10 (Starfire Systems), were studied. In order to produce high qualities of silicon carbide cantilevers, where the major concern is defects, proper process parameters needed to be determined. Films of polymer derived ceramics often have defects due to shrinkage during the conversion process. Thus control of defects was a central issue in this study. A second, related concern was preventing oxidation; the polymer derived ceramics we chose is easily oxidized during processing. Establishing an environment without oxygen in the whole process was a significant challenge in the project. The optimization of the parameters for using photolithography and wet etching process was the final and central goal of the project; well established techniques used in microfabrication were modified for use in making the cantilever in the project. The techniques

Polymer Ferroelectric Memory for Flexible Electronics

KAUST Repository

Khan, Mohd Adnan

2013-01-01

With the projected growth of the flexible and plastic electronics industry, there is renewed interest in the research community to develop high performance all-polymeric memory which will be an essential component of any electronic circuit. Some of the efforts in polymer memories are based on different mechanisms such as filamentary conduction, charge trapping effects, dipole alignment, and reduction-oxidation to name a few. Among these the leading candidate are those based on the mechanism of ferroelectricity. Polymer ferroelectric memory can be used in niche applications like smart cards, RFID tags, sensors etc. This dissertation will focus on novel material and device engineering to fabricate high performance low temperature polymeric ferroelectric memory for flexible electronics. We address and find solutions to some fundamental problems affecting all polymer ferroelectric memory like high coercive fields, fatigue and thermal stability issues, poor breakdown strength and poor p-type hole mobilities. Some of the strategies adopted in this dissertation are: Use of different flexible substrates, electrode engineering to improve charge injection and fatigue properties of ferroelectric polymers, large area ink jet printing of ferroelectric memory devices, use of polymer blends to improve insulating properties of ferroelectric polymers and use of oxide semiconductors to fabricate high mobility p-type ferroelectric memory. During the course of this dissertation we have fabricated: the first all-polymer ferroelectric capacitors with solvent modified highly conducting polymeric poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) [PEDOT:PSS] electrodes on plastic substrates with performance as good as devices with metallic Platinum-Gold electrodes on silicon substrates; the first all-polymer high performance ferroelectric memory on banknotes for security applications; novel ferroelectric capacitors based on blends of ferroelectric poly(vinylidene fluoride

Polymer Ferroelectric Memory for Flexible Electronics

KAUST Repository

Khan, Mohd Adnan

2013-11-01

With the projected growth of the flexible and plastic electronics industry, there is renewed interest in the research community to develop high performance all-polymeric memory which will be an essential component of any electronic circuit. Some of the efforts in polymer memories are based on different mechanisms such as filamentary conduction, charge trapping effects, dipole alignment, and reduction-oxidation to name a few. Among these the leading candidate are those based on the mechanism of ferroelectricity. Polymer ferroelectric memory can be used in niche applications like smart cards, RFID tags, sensors etc. This dissertation will focus on novel material and device engineering to fabricate high performance low temperature polymeric ferroelectric memory for flexible electronics. We address and find solutions to some fundamental problems affecting all polymer ferroelectric memory like high coercive fields, fatigue and thermal stability issues, poor breakdown strength and poor p-type hole mobilities. Some of the strategies adopted in this dissertation are: Use of different flexible substrates, electrode engineering to improve charge injection and fatigue properties of ferroelectric polymers, large area ink jet printing of ferroelectric memory devices, use of polymer blends to improve insulating properties of ferroelectric polymers and use of oxide semiconductors to fabricate high mobility p-type ferroelectric memory. During the course of this dissertation we have fabricated: the first all-polymer ferroelectric capacitors with solvent modified highly conducting polymeric poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) [PEDOT:PSS] electrodes on plastic substrates with performance as good as devices with metallic Platinum-Gold electrodes on silicon substrates; the first all-polymer high performance ferroelectric memory on banknotes for security applications; novel ferroelectric capacitors based on blends of ferroelectric poly(vinylidene fluoride

Thermo-acoustical analysis of sodium dodecyl sulfate: Fluconazole (antifungal drug) based micellar system in hydro-ethanol solutions for potential drug topical application

International Nuclear Information System (INIS)

Bhardwaj, Tarun; Bhardwaj, Varun; Sharma, Kundan; Gupta, Abhishek; Cameotra, Swaranjit Singh; Sharma, Poonam

2014-01-01

Highlights: • The mixed micellar system was analyzed for sodium dodecyl sulfate and fluconazole. • Early micellization was found with CMC shift towards lower surfactant concentration. • Negative ΔG m o values suggested that the micelle formation is spontaneous and feasible. • Thermo-acoustical parameters revealed the existence of intermolecular interactions within the molecules. - Abstract: Micellar systems hold excellent drug delivery applications due to their capability to solubilize a large number of hydrophobic and hydrophilic molecules. In this present work, the mixed micelle formation between the anionic surfactant sodium dodecyl sulfate (SDS) and the ‘Azole’ derivative antifungal drug fluconazole (FLZ) have been studied at four temperatures in different hydro-ethanolic solutions. The critical micelle concentration (CMC) was determined by specific conductance techniques and the experimental data was used to calculate several useful thermodynamic parameters, like standard free energy, enthalpy and entropy of micelle formation. Early micellization was found with critical micelle concentration shifting towards lower concentration (CMC) than the standard concentration of SDS in water at 25 °C suggesting that drug and the solvent system facilitates the micellization process. In addition, the transport properties were examined by employing controlled approaches likely, apparent molar volume (ϕ v ), apparent molar adiabatic compression (ϕ k ), and isentropic compression (κ s ) of SDS in presence of FLZ. These parameters revealed the existence of intermolecular interactions within the molecules. Therefore, this study would cast light on utilizing surfactant immobilized FLZ system for better topical biological action

Development of polymer films by the coalescence of polymer particles in powdered and aqueous polymer-modified mortars

International Nuclear Information System (INIS)

Afridi, M.U.K.; Ohama, Y.; Demura, K.; Iqbal, M.Z.

2003-01-01

This paper evaluates and compares the coalescence of polymer particles (continuous polymer films formation) in powdered polymer-modified mortars (PPMMs) and aqueous polymer-modified mortars (APMMs). Polymer-modified mortars (PMMs) using various redispersible polymer powders (powdered cement modifiers) and polymer dispersions (aqueous cement modifiers) were prepared by varying the polymer-cement ratio (P/C) and were tested for the characterization of polymer films using a scanning electron microscope (SEM) after curing for 28 days. It is concluded from the test results that mortar constituents of unmodified mortar (UMM) are loosely joined with each other due to the absence of polymer films, thus having a structure with comparatively lower mechanical and durability characteristics. By contrast, mortar constituents in PPMMs and APMMs are compactly joined with each other due to the presence of interweaving polymer films, thereby forming a monolithic structure with improved mechanical and durability characteristics. However, the results make obvious the poor coalescence of polymer particles or development of inferior quality polymers films in PPMMs as compared to that observed in APMMs. Moreover, PPMMs show less uniform distribution of polymer films as compared to that in APMMs. Different powdered cement modifiers have different film-forming capabilities. However, such difference is hardly recognized in aqueous cement modifiers. The polymer films in PPMMs and APMMs may acquire different structures. They may appear as mesh-like, thread-like, rugged, dense or fibrous with fine or rough surfaces. Development of coherent polymer films is not well pronounced at a P/C of 5% in PPMMs, whereas sometimes coherent polymer films are observed at a P/C of 5% in APMMs. At a P/C of 10% or more, fully developed, coherent polymer films are observed in both PPMMs and APMMs

Ceramic/polymer functionally graded material (FGM) lightweight armor system

Energy Technology Data Exchange (ETDEWEB)

Petrovic, J.J.; McClellan, K.J.

1998-12-31

This is the final report of a two-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Functionally graded material is an enabling technology for lightweight body armor improvements. The objective was to demonstrate the ability to produce functionally graded ceramic-polymer and ceramic-metal lightweight armor materials. This objective involved two aspects. The first and key aspect was the development of graded-porosity boron-carbide ceramic microstructures. The second aspect was the development of techniques for liquid infiltration of lightweight metals and polymers into the graded-porosity ceramic. The authors were successful in synthesizing boron-carbide ceramic microstructures with graded porosity. These graded-porosity boron-carbide hot-pressed pieces were then successfully liquid-infiltrated in vacuum with molten aluminum at 1,300 C, and with liquid polymers at room temperature. Thus, they were able to demonstrate the feasibility of producing boron carbide-aluminum and boron carbide-polymer functionally graded materials.

Neutral Polymer Micelle Carriers with pH-Responsive, Endosome-Releasing Activity Modulate Antigen Trafficking to Enhance CD8 T-Cell Responses

Science.gov (United States)

Keller, Salka; Wilson, John T; Patilea, Gabriela I; Kern, Hanna B; Convertine, Anthony J; Stayton, Patrick S

2014-01-01

Synthetic subunit vaccines need to induce CD8+ cytotoxic T-cell (CTL) responses for effective vaccination against intracellular pathogens. Most subunit vaccines primarily generate humoral immune responses, with a weaker than desired CD8+ cytotoxic T-cell response. Here, a neutral, pH-responsive polymer micelle carrier that alters intracellular antigen trafficking was shown to enhance CD8+ T-cell responses with a correlated increase in cytosolic delivery and a decrease in exocytosis. Polymer diblock carriers consisted of a N-(2-hydroxypropyl) methacrylamide corona block with pendant pyridyl disulfide groups for reversible conjugation of thiolated ovalbumin, and a tercopolymer ampholytic core-forming block composed of propylacrylic acid (PAA), dimethylaminoethyl methacrylate (DMAEMA), and butyl methacrylate (BMA). The diblock copolymers self-assembled into 25–30 nm diameter micellar nanoparticles. Conjugation of ovalbumin to the micelles significantly enhanced antigen cross-presentation in vitro relative to free ovalbumin, an unconjugated physical mixture of ovalbumin and polymer, and a non pH-responsive micelle-ovalbumin control. Mechanistic studies in a murine dendritic cell line (DC2.4) demonstrated micelle-mediated enhancements in intracellular antigen retention and cytosolic antigen accumulation. Approximately 90% of initially internalized ovalbumin-conjugated micelles were retained in cells after 1.5 h, compared to only ~40% for controls. Furthermore, cells dosed with conjugates displayed 67-fold higher cytosolic antigen levels relative to soluble ovalbumin 4 h post uptake. Subcutaneous immunization of mice with ovalbumin-polymer conjugates significantly enhanced antigen-specific CD8+ T cell responses (0.4 % IFN-γ+ of CD8+) compared to immunization with soluble protein, ovalbumin and polymer mixture, and the control micelle without endosome-releasing activity. Additionally, pH-responsive carrier facilitated antigen delivery to antigen presenting cells in the

Neutral polymer micelle carriers with pH-responsive, endosome-releasing activity modulate antigen trafficking to enhance CD8(+) T cell responses.

Science.gov (United States)

Keller, Salka; Wilson, John T; Patilea, Gabriela I; Kern, Hanna B; Convertine, Anthony J; Stayton, Patrick S

2014-10-10

Synthetic subunit vaccines need to induce CD8(+) cytotoxic T cell (CTL) responses for effective vaccination against intracellular pathogens. Most subunit vaccines primarily generate humoral immune responses, with a weaker than desired CD8(+) cytotoxic T cell response. Here, a neutral, pH-responsive polymer micelle carrier that alters intracellular antigen trafficking was shown to enhance CD8(+) T cell responses with a correlated increase in cytosolic delivery and a decrease in exocytosis. Polymer diblock carriers consisted of a N-(2-hydroxypropyl) methacrylamide corona block with pendent pyridyl disulfide groups for reversible conjugation of thiolated ovalbumin, and a tercopolymer ampholytic core-forming block composed of propylacrylic acid (PAA), dimethylaminoethyl methacrylate (DMAEMA), and butyl methacrylate (BMA). The diblock copolymers self-assembled into 25-30nm diameter micellar nanoparticles. Conjugation of ovalbumin to the micelles significantly enhanced antigen cross-presentation in vitro relative to free ovalbumin, an unconjugated physical mixture of ovalbumin and polymer, and a non-pH-responsive micelle-ovalbumin control. Mechanistic studies in a murine dendritic cell line (DC 2.4) demonstrated micelle-mediated enhancements in intracellular antigen retention and cytosolic antigen accumulation. Approximately 90% of initially internalized ovalbumin-conjugated micelles were retained in cells after 1.5h, compared to only ~40% for controls. Furthermore, cells dosed with conjugates displayed 67-fold higher cytosolic antigen levels relative to soluble ovalbumin 4h post uptake. Subcutaneous immunization of mice with ovalbumin-polymer conjugates significantly enhanced antigen-specific CD8(+) T cell responses (0.4% IFN-γ(+) of CD8(+)) compared to immunization with soluble protein, ovalbumin and polymer mixture, and the control micelle without endosome-releasing activity. Additionally, pH-responsive carrier facilitated antigen delivery to antigen presenting cells

Polymer films

Science.gov (United States)

Granick, Steve; Sukhishvili, Svetlana A.

2004-05-25

A film contains a first polymer having a plurality of hydrogen bond donating moieties, and a second polymer having a plurality of hydrogen bond accepting moieties. The second polymer is hydrogen bonded to the first polymer.

Novel polymer vectors of Cu-64

Czech Academy of Sciences Publication Activity Database

Kozempel, J.; Hrubý, Martin; Nováková, Michaela; Kučka, Jan; Lešetický, L.; Lebeda, Ondřej

2009-01-01

Roč. 97, - (2009), s. 747-752 ISSN 0033-8230 R&D Projects: GA AV ČR IAA400480616; GA AV ČR KJB4050408; GA AV ČR KAN200200651 Institutional research plan: CEZ:AV0Z40500505; CEZ:AV0Z10480505 Keywords : copper-64 * polymer * chelating group Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.459, year: 2009

Underwater Fiber Reinforced Polymer (FRP) Wrap Experimental Project

Science.gov (United States)

2018-01-30

In 2017, The Maine Department of Transportation in collaboration with the Kenway Corporation and Construction Divers Inc. (CDI), completed a rehabilitation project on the Rices Bridge (#2715) over the York River in York, Maine. The project was to add...

Adsorption and flocculation by polymers and polymer mixtures.

Science.gov (United States)

Gregory, John; Barany, Sandor

2011-11-14

Polymers of various types are in widespread use as flocculants in several industries. In most cases, polymer adsorption is an essential prerequisite for flocculation and kinetic aspects are very important. The rates of polymer adsorption and of re-conformation (relaxation) of adsorbed chains are key factors that influence the performance of flocculants and their mode of action. Polyelectrolytes often tend to adopt a rather flat adsorbed configuration and in this state their action is mainly through charge effects, including 'electrostatic patch' attraction. When the relaxation rate is quite low, particle collisions may occur while the adsorbed chains are still in an extended state and flocculation by polymer bridging may occur. These effects are now well understood and supported by much experimental evidence. In recent years there has been considerable interest in the use of multi-component flocculants, especially dual-polymer systems. In the latter case, there can be significant advantages over the use of single polymers. Despite some complications, there is a broad understanding of the action of dual polymer systems. In many cases the sequence of addition of the polymers is important and the pre-adsorbed polymer can have two important effects: providing adsorption sites for the second polymer or causing a more extended adsorbed conformation as a result of 'site blocking'. Copyright © 2011 Elsevier B.V. All rights reserved.

Micellar effect on the sensitivity of spectrophotometric Mo(VI) determination based on the formation of gallic acid complex providing evidence for the polyoxoanion structure of molybdate ions

International Nuclear Information System (INIS)

Tascioglu, Senay; Sendil, Olcay; Beyreli, Sivekar

2007-01-01

In this study effects of anionic (sodium dodecyl sulfate, SDS), cationic (cetyltrimethylammonium bromide, CTAB) and nonionic (Triton X-100, TX100) micelles on the sensitivity of spectrophotometric molybdenum(VI) (Mo) determination based on the formation of a binary complex with gallic acid (GA) were investigated. Micellar CTAB was found to enhance the formation of Mo-GA complex. SDS micelles exerted an inhibitory effect while TX100 micelles had no effect on the complex formation. By the optimization of experimental conditions, the determination limit of the method suggested in the literature was lowered from 5.2 x 10 -5 to 4.6 x 10 -6 and to 5.7 x 10 -7 M, in the absence and presence of CTAB, respectively. The mechanism of the effect of CTAB was investigated by spectrophotometric titrations and it was concluded that CTAB did not form a ternary complex with Mo and GA. The stoichiometry of the complex, deduced from the results of spectrophotometric titrations, provided evidence for the formation of para-Mo 7 O 4 6- polyanions at pH 4.5, indicating to the formation of a charge transfer complex between these ions and GA in micellar medium

Molybdenum and tungsten disulfides surface-modified with a conducting polymer, polyaniline, for application in electrorheology

Czech Academy of Sciences Publication Activity Database

Stejskal, Jaroslav; Mrlík, M.; Plachý, T.; Trchová, Miroslava; Kovářová, Jana; Li, Yu

2017-01-01

Roč. 120, November (2017), s. 30-37 ISSN 1381-5148 R&D Projects: GA ČR(CZ) GA17-04109S Institutional support: RVO:61389013 Keywords : molybdenum sulfide * polyaniline * conducting polymer Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 3.151, year: 2016

Smart polymers in drug delivery systems on crossroads: which way deserves following?

Czech Academy of Sciences Publication Activity Database

Hrubý, Martin; Filippov, Sergey K.; Štěpánek, Petr

2015-01-01

Roč. 65, April (2015), s. 82-97 ISSN 0014-3057 R&D Projects: GA ČR GAP304/12/0950; GA MŠk(CZ) LH14292; GA MŠk(CZ) 7F14009; GA ČR(CZ) GA13-08336S Institutional support: RVO:61389013 Keywords : stimuli responsive polymers * drug delivery * thermosensitive polymers Subject RIV: CC - Organic Chemistry Impact factor: 3.485, year: 2015

Influence of topology of highly porous methacrylate polymers on their mechanical properties

Czech Academy of Sciences Publication Activity Database

Paljevac, M.; Kotek, Jiří; Jeřábek, Karel; Krajnc, P.

2018-01-01

Roč. 303, č. 2 (2018), s. 1-8, č. článku 1700337. ISSN 1438-7492 R&D Projects: GA MŠk(CZ) LO1507 Institutional support: RVO:61389013 ; RVO:67985858 Keywords : mechanical properties * methacrylate monoliths * polymer topology Subject RIV: CD - Macromolecular Chemistry; CC - Organic Chemistry (UCHP-M) OBOR OECD: Polymer science; Organic chemistry (UCHP-M) Impact factor: 2.863, year: 2016

Thermoresponsive polymers as promising new materials for local radiotherapy

Czech Academy of Sciences Publication Activity Database

Hrubý, Martin; Šubr, Vladimír; Kučka, J.; Kozempel, J.; Lebeda, Ondřej; Sikora, Antonín

2005-01-01

Roč. 63, č. 4 (2005), s. 423-431 ISSN 0969-8043 R&D Projects: GA AV ČR KJB4050408 Keywords : thermoresponsive * polymer * poly(N-isopropyl acrylamide) Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.757, year: 2005

Controlling of degradation effects in radiation processing of polymers

International Nuclear Information System (INIS)

2009-05-01

The interest of Member States of the IAEA in introducing radiation technology into the polymer and plastics industry is growing. This publication summarizes a number of studies conducted in the framework of a coordinated research project (CRP) on controlling of degradation effects on polymers by radiation processing technologies. It reviews a variety of applications and details the most important results and achievements of the participating centres and laboratories during the course of the CRP. The publication is intended to be of use to scientists implementing the technology and managers of radiation processing facilities

Thermoresponsive polymer nanoparticles co-deliver RSV F trimers with a TLR-7/8 adjuvant

Czech Academy of Sciences Publication Activity Database

Francica, J. R.; Lynn, G. M.; Laga, Richard; Joyce, M. G.; Ruckwardt, T. J.; Morabito, K. M.; Chen, M.; Chaudhuri, R.; Zhang, B.; Sastry, M.; Druz, A.; Ko, K.; Choe, M.; Pechar, Michal; Georgiev, I. S.; Kueltzo, L. A.; Seymour, L. W.; Mascola, J. R.; Kwong, P. D.; Graham, B. S.; Seder, R. A.

2016-01-01

Roč. 27, č. 10 (2016), s. 2372-2385 ISSN 1043-1802 R&D Projects: GA ČR(CZ) GJ16-14957Y; GA MŠk(CZ) LQ1604 Institutional support: RVO:61389013 Keywords : thermoresponsive polymers * polymer vaccines * toll-like receptor agonists Subject RIV: CD - Macromolecular Chemistry Impact factor: 4.818, year: 2016

Comparison of micellar extraction combined with ionic liquid based vortex-assisted liquid-liquid microextraction and modified quick, easy, cheap, effective, rugged, and safe method for the determination of difenoconazole in cowpea.

Science.gov (United States)

Chen, Xiaochu; Bian, Yanli; Liu, Fengmao; Teng, Peipei; Sun, Pan

2017-10-06

Two simple sample pretreatment for the determination of difenoconazole in cowpea was developed including micellar extraction combined with ionic liquid based vortex-assisted liquid-liquid microextraction (ME-IL-VALLME) prior to high performance liquid chromatography (HPLC), and modified quick, easy, cheap, effective, rugged, and safe method (QuEChERS) coupled with HPLC-MS/MS. In ME-IL-VALLME method, the target analyte was extracted by surfactant Tween 20 micellar solution, then the supernatant was diluted with 3mL water to decrease the solubility of micellar solution. Subsequently, the vortex-assisted liquid-liquid microextraction (VALLME) procedure was performed in the diluted extraction solution by using the ionic liquid of 1-hexyl-3-methylimidazolium hexafluorophosphate ([HMIM]PF 6 ) as the extraction solvent and Tween 20 as an emulsifier to enhance the dispersion of the water-immiscible ionic liquid into the aqueous phase. Parameters that affect the extraction have been investigated in both methods Under the optimum conditions, the limits of quantitation were 0.10 and 0.05mgkg -1 , respectively. And good linearity was achieved with the correlation coefficient higher than 0.9941. The relative recoveries ranged from 78.6 to 94.8% and 92.0 to 118.0% with the relative standard deviations (RSD) of 7.9-9.6% and 1.2-3.2%, respectively. Both methods were quick, simple and inexpensive. However, the ME-IL-VALLME method provides higher enrichment factor compared with conventional QuEChERS method. The ME-IL-VALLME method has a strong potential for the determination of difenoconazole in complex vegetable matrices with HPLC. Copyright © 2017 Elsevier B.V. All rights reserved.

Polymer crowding and shape distributions in polymer-nanoparticle mixtures

Energy Technology Data Exchange (ETDEWEB)

Lim, Wei Kang; Denton, Alan R., E-mail: alan.denton@ndsu.edu [Department of Physics, North Dakota State University, Fargo, North Dakota 58108-6050 (United States)

2014-09-21

Macromolecular crowding can influence polymer shapes, which is important for understanding the thermodynamic stability of polymer solutions and the structure and function of biopolymers (proteins, RNA, DNA) under confinement. We explore the influence of nanoparticle crowding on polymer shapes via Monte Carlo simulations and free-volume theory of a coarse-grained model of polymer-nanoparticle mixtures. Exploiting the geometry of random walks, we model polymer coils as effective penetrable ellipsoids, whose shapes fluctuate according to the probability distributions of the eigenvalues of the gyration tensor. Accounting for the entropic cost of a nanoparticle penetrating a larger polymer coil, we compute the crowding-induced shift in the shape distributions, radius of gyration, and asphericity of ideal polymers in a theta solvent. With increased nanoparticle crowding, we find that polymers become more compact (smaller, more spherical), in agreement with predictions of free-volume theory. Our approach can be easily extended to nonideal polymers in good solvents and used to model conformations of biopolymers in crowded environments.

Polymer crowding and shape distributions in polymer-nanoparticle mixtures

International Nuclear Information System (INIS)

Lim, Wei Kang; Denton, Alan R.

2014-01-01

Macromolecular crowding can influence polymer shapes, which is important for understanding the thermodynamic stability of polymer solutions and the structure and function of biopolymers (proteins, RNA, DNA) under confinement. We explore the influence of nanoparticle crowding on polymer shapes via Monte Carlo simulations and free-volume theory of a coarse-grained model of polymer-nanoparticle mixtures. Exploiting the geometry of random walks, we model polymer coils as effective penetrable ellipsoids, whose shapes fluctuate according to the probability distributions of the eigenvalues of the gyration tensor. Accounting for the entropic cost of a nanoparticle penetrating a larger polymer coil, we compute the crowding-induced shift in the shape distributions, radius of gyration, and asphericity of ideal polymers in a theta solvent. With increased nanoparticle crowding, we find that polymers become more compact (smaller, more spherical), in agreement with predictions of free-volume theory. Our approach can be easily extended to nonideal polymers in good solvents and used to model conformations of biopolymers in crowded environments

Electrolyte penetration into high energy ion irradiated polymers

Czech Academy of Sciences Publication Activity Database

Fink, D.; Petrov, A.; Müller, M.; Asmus, T.; Hnatowicz, Vladimír; Vacík, Jiří; Červená, Jarmila

158/159 (2002), s. 228-233 ISSN 0257-8972 R&D Projects: GA AV ČR KSK1010104; GA ČR GA102/01/1324 Keywords : polymers * ion bombardment * defects * diffusion * nanostructrure Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.267, year: 2002

Cation-sensitive compartmentalization in metallacarborane containing polymer nanoparticles

Czech Academy of Sciences Publication Activity Database

Ďorďovič, V.; Uchman, M.; Reza, M.; Ruokolainen, J.; Zhigunov, Alexander; Ivankov, O. I.; Matějíček, P.

2016-01-01

Roč. 6, č. 12 (2016), s. 9884-9892 ISSN 2046-2069 R&D Projects: GA ČR(CZ) GA14-14608S Institutional support: RVO:61389013 Keywords : polymer nanoparticles * metallacarborane * double-hydrophilic block copolymer Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.108, year: 2016

Structure and Dynamics of Polymer/Polymer grafted nanoparticle composite

Science.gov (United States)

Archer, Lynden

Addition of nanoparticles to polymers is a well-practiced methodology for augmenting various properties of the polymer host, including mechanical strength, thermal stability, barrier properties, dimensional stability and wear resistance. Many of these property changes are known to arise from nanoparticle-induced modification of polymer structure and chain dynamics, which are strong functions of the dispersion state of the nanoparticles' and on their relative size (D) to polymer chain dimensions (e.g. Random coil radius Rg or entanglement mesh size a) . This talk will discuss polymer nanocomposites (PNCs) comprised of Polyethylene Glycol (PEG) tethered silica nanoparticles (SiO2-PEG) dispersed in polymers as model systems for investigating phase stability and dynamics of PNCs. On the basis of small-angle X-ray Scattering, it will be shown that favorable enthalpic interactions between particle-tethered chains and a polymer host provides an important mechanism for creating PNCs in which particle aggregation is avoided. The talk will report on polymer and particle scale dynamics in these materials and will show that grafted nanoparticles well dispersed in a polymer host strongly influence the host polymer relaxation dynamics on all timescales and the polymers in turn produce dramatic changes in the nature (from diffusive to hyperdiffusive) and speed of nano particle decorrelation dynamics at the polymer entanglement threshold. A local viscosity model capable of explaining these observations is discussed and the results compared with scaling theories for NP motions in polymers This material is based on work supported by the National Science Foundation Award Nos. DMR-1609125 and CBET-1512297.

The effect of ionizing radiation on biocompatible polymers: From sterilization to radiolysis and hydrogel formation

Czech Academy of Sciences Publication Activity Database

Sedláček, Ondřej; Kučka, Jan; Monnery, B. D.; Šlouf, Miroslav; Vetrík, Miroslav; Hoogenboom, R.; Hrubý, Martin

2017-01-01

Roč. 137, March (2017), s. 1-10 ISSN 0141-3910 R&D Projects: GA ČR(CZ) GA13-08336S; GA MZd(CZ) NV15-25781A; GA MZd(CZ) NV16-30544A; GA MŠk(CZ) LH14079; GA MŠk(CZ) LO1507 Institutional support: RVO:61389013 Keywords : biocompatible polymers * radiation crosslinking * polymer radiotherapeutics Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 3.386, year: 2016

Polymer dynamics from synthetic polymers to proteins

Indian Academy of Sciences (India)

Keywords. Polymer dynamics; reptation; domain dynamics biomolecules. Abstract. Starting from the standard model of polymer motion - the Rouse model - we briefly present some key experimental results on the mesoscopic dynamics of polymer systems. We touch the role of topological confinement as expressed in the ...

Formation of highly structured cubic micellar lipid nanoparticles of soy phosphatidylcholine and glycerol dioleate and their degradation by triacylglycerol lipase.

Science.gov (United States)

Wadsäter, Maria; Barauskas, Justas; Nylander, Tommy; Tiberg, Fredrik

2014-05-28

Lipid nanoparticles of reversed internal phase structures, such as cubic micellar (I2) structure show good drug loading ability of peptides and proteins as well as some small molecules. Due to their controllable small size and inner morphology, such nanoparticles are suitable for drug delivery using several different administration routes, including intravenous, intramuscular, and subcutaneous injection. A very interesting system in this regard, is the two component soy phosphatidylcholine (SPC)/glycerol dioleate (GDO) system, which depending on the ratio of the lipid components form a range of reversed liquid crystalline phases. For a 50/50 (w/w) ratio in excess water, these lipids have been shown to form a reversed cubic micellar (I2) phase of the Fd3m structure. Here, we demonstrate that this SPC/GDO phase, in the presence of small quantities (5-10 wt %) of Polysorbate 80 (P80), can be dispersed into nanoparticles, still with well-defined Fd3m structure. The resulting nanoparticle dispersion has a narrow size distribution and exhibit good long-term stability. In pharmaceutical applications, biodegradation pathways of the drug delivery vehicles and their components are important considerations. In the second part of the study we show how the structure of the particles evolves during exposure to a triacylglycerol lipase (TGL) under physiological-like temperature and pH. TGL catalyzes the lipolytic degradation of acylglycerides, such as GDO, to monoglycerides, glycerol, and free fatty acids. During the degradation, the interior phase of the particles is shown to undergo continuous phase transitions from the reversed I2 structure to structures of less negative curvature (2D hexagonal, bicontinuous cubic, and sponge), ultimately resulting in the formation of multilamellar vesicles.

Determination of the quaternary structural states of bovine casein by small-angle X-ray scattering: submicellar and micellar forms

International Nuclear Information System (INIS)

Kumosinski, T.F.; Pessen, H.; Farrell, H.M. Jr.; Brumberger, H.

1988-01-01

Whole casein occurs in milk as a spherical colloidal complex of protein and salts called the casein micelle, with approximate average radii of 650 A as determined by electron microscopy. Removal of Ca2+ is thought to result in dissociation into smaller noncolloidal protein complexes called submicelles. Hydrodynamic and light scattering studies on whole casein submicelles suggest that they are predominantly spherical particles with a hydrophobic core. To investigate whether the integrity of a hydrophobically stabilized submicellar structure is preserved in the electrostatically stabilized colloidal micellar structure, small-angle X-ray scattering (SAXS) experiments were undertaken on whole casein from bovine milk under submicellar and micellar conditions. All SAXS results showed multiple Gaussian character and could be analyzed best by nonlinear regression in place of the customary Guinier plot. Analysis of the SAXS data for submicellar casein showed two Gaussian components which could be interpreted in terms of a particle with two concentric regions of different electron density, designated as a compact core and a loose shell, respectively. The submicelle was found to have an average molecular weight of 285,000 +/- 14,600 and a mass fraction of higher electron density core, k, of 0.212 +/- 0.028. The radius of gyration of the core, RC, was 37.98 +/- 0.01 A with an electron density difference, delta rho C, of 0.0148 +/- 0.0014 e-/A3, while the loose region had values of RL = 88.2 +/- 0.8 A with delta rho L = 0.0091 +/- 0.0003 e-/A3. Calculated distance distribution functions and normalized scattering curves also were consistent with an overall spherical particle with a concentric spherical inner core of higher electron density. (Abstract Truncated)

Industrialisation of polymer solar cells. Phase 2: Consolidation

Energy Technology Data Exchange (ETDEWEB)

Lauritzen, H.; Gevorgyan, S.; Frausig, J.; Andersen, Rasmus B.; Krebs, F.C.

2013-03-15

The key results from the project are: a firmly anchoring of DTU's basic polymer solar cell technology, ProcessOne, at Mekoprint, improved documented operational lifetime for polymer solar modules, and optimized processing of such modules. Mekoprint has worked determinedly to stabilize their production of ProcessOne devices, to prepare for full scale production and to build a marked for polymer solar cells. Work has been invested in improvement of process tolerances, documentation of the production process, training of process operators and roll-to-roll characterization of the produced solar cells. The planned and conducted actions have been summed up in a SIPOC diagram. Mekoprint's communication with potential customers reveals that lowering the cost, increasing the efficiency and operational life time is important for reaching the commercial market. Activities aimed at penetrating the market for lighting products in 3{sup rd} world countries are intensified. A new solar cell laser pointer is developed and a series of 2000 has been produced for the purpose of creating a commercial focus on polymer solar cells. DTU has established a characterization laboratory for organic photovoltaics (CLOP). The laboratory allows for real-time - and accelerated lifetime testing of solar cells both indoor and outdoor, and thus for the development of reliable methods for predicting life-time from accelerated testing. An operational lifetime of 2 years has, by means of the method, been documented for polymer solar modules encapsulated in a food-packaging barrier. Preliminary accelerated measurements on an equivalent device encapsulated in the same barrier, but in two layers, show a five times improvement of the solar cell stability. On basis of this it is considered that five years operational lifetime is within reach. DTU has improved of their OPV production technology by replacing the purchased vacuum-processed indium-tin-oxide (ITO) electrode by a roll-to-roll processed

Industrialisation of polymer solar cells. Phase 2: Consolidation

Energy Technology Data Exchange (ETDEWEB)

Lauritzen, H.; Gevorgyan, S.; Frausig, J.; Andersen, Rasmus B.; Krebs, F. C.

2013-03-15

The key results from the project are: a firmly anchoring of DTU's basic polymer solar cell technology, ProcessOne, at Mekoprint, improved documented operational lifetime for polymer solar modules, and optimized processing of such modules. Mekoprint has worked determinedly to stabilize their production of ProcessOne devices, to prepare for full scale production and to build a marked for polymer solar cells. Work has been invested in improvement of process tolerances, documentation of the production process, training of process operators and roll-to-roll characterization of the produced solar cells. The planned and conducted actions have been summed up in a SIPOC diagram. Mekoprint's communication with potential customers reveals that lowering the cost, increasing the efficiency and operational life time is important for reaching the commercial market. Activities aimed at penetrating the market for lighting products in 3{sup rd} world countries are intensified. A new solar cell laser pointer is developed and a series of 2000 has been produced for the purpose of creating a commercial focus on polymer solar cells. DTU has established a characterization laboratory for organic photovoltaics (CLOP). The laboratory allows for real-time - and accelerated lifetime testing of solar cells both indoor and outdoor, and thus for the development of reliable methods for predicting life-time from accelerated testing. An operational lifetime of 2 years has, by means of the method, been documented for polymer solar modules encapsulated in a food-packaging barrier. Preliminary accelerated measurements on an equivalent device encapsulated in the same barrier, but in two layers, show a five times improvement of the solar cell stability. On basis of this it is considered that five years operational lifetime is within reach. DTU has improved of their OPV production technology by replacing the purchased vacuum-processed indium-tin-oxide (ITO) electrode by a roll-to-roll processed electrode

Fluorescence resonance energy transfer between perylene and riboflavin in micellar solution and analytical application on determination of vitamin B2

International Nuclear Information System (INIS)

Bhattar, S.L.; Kolekar, G.B.; Patil, S.R.

2008-01-01

Fluorescence resonance energy transfer (FRET) between perylene and riboflavin is studied in micellar solution of sodium dodecyl sulfate. The fluorescence of perylene is quenched by riboflavin and quenching is in accordance with Stern-Volmer relation. The efficiency of energy transfer is found to depend on the concentration of riboflavin. The value of critical energy transfer distance (R 0 ) calculated by using Foster relation is 32.13 A, and as it is less than 50 A, it indicates efficient energy transfer in the present system. The analytical relation was established between extent of sensitization and concentration of riboflavin, which helped to estimate vitamin B 2 directly from pharmaceutical tablets

On the predictions and limitations of the Becker–Döring model for reaction kinetics in micellar surfactant solutions

KAUST Repository

Griffiths, I.M.

2011-08-01

We investigate the breakdown of a system of micellar aggregates in a surfactant solution following an order-one dilution. We derive a mathematical model based on the Becker-Döring system of equations, using realistic expressions for the reaction constants fit to results from Molecular Dynamics simulations. We exploit the largeness of typical aggregation numbers to derive a continuum model, substituting a large system of ordinary differential equations for a partial differential equation in two independent variables: time and aggregate size. Numerical solutions demonstrate that re-equilibration occurs in two distinct stages over well-separated timescales, in agreement with experiment and with previous theories. We conclude by exposing a limitation in the Becker-Döring theory for re-equilibration of surfactant solutions. © 2011 Elsevier Inc.

Polymer compound

NARCIS (Netherlands)

1995-01-01

A Polymer compound comprising a polymer (a) that contains cyclic imidesgroups and a polymer (b) that contains monomer groups with a 2,4-diamino-1,3,5-triazine side group. According to the formula (see formula) whereby themole percentage ratio of the cyclic imides groups in the polymer compoundwith

Responsive copolymers for enhanced petroleum recovery. Quarterly technical progress report, December 21, 1994--March 22, 1995

Energy Technology Data Exchange (ETDEWEB)

McCormick, C.; Hester, R.

1995-05-01

The purpose of this study is to extend the concept of micellar polymerization to more complex systems, and to explore the responsive nature of hydrophobically modified polyelectrolytes by tailoring the microstructure. The synthesis of hydrophobically modified acrylamide/acrylic acid copolymer is described. These types of polymers are of interest as thickening agents utilized in enhanced oil recovery.

Polymer nanotherapeutics to overcome multidrug resistance

Czech Academy of Sciences Publication Activity Database

Braunová, Alena; Kostka, Libor; Sivák, Ladislav; Filippov, Sergey K.; Pechar, Michal; Janoušková, Olga; Šírová, Milada; Etrych, Tomáš

2017-01-01

Roč. 6, 4 (Suppl) (2017), s. 92 ISSN 2325-9604. [International Conference and Exhibition on Nanomedicine and Drug Delivery. 29.05.2017-31.05.2017, Osaka] R&D Projects: GA ČR(CZ) GA16-17207S; GA MZd(CZ) NV16-28600A Institutional support: RVO:61389013 ; RVO:61388971 Keywords : polymer- drug carrier * micelle * controlled drug release Subject RIV: CD - Macromolecular Chemistry

Star Polymers.

Science.gov (United States)

Ren, Jing M; McKenzie, Thomas G; Fu, Qiang; Wong, Edgar H H; Xu, Jiangtao; An, Zesheng; Shanmugam, Sivaprakash; Davis, Thomas P; Boyer, Cyrille; Qiao, Greg G

2016-06-22

Recent advances in controlled/living polymerization techniques and highly efficient coupling chemistries have enabled the facile synthesis of complex polymer architectures with controlled dimensions and functionality. As an example, star polymers consist of many linear polymers fused at a central point with a large number of chain end functionalities. Owing to this exclusive structure, star polymers exhibit some remarkable characteristics and properties unattainable by simple linear polymers. Hence, they constitute a unique class of technologically important nanomaterials that have been utilized or are currently under audition for many applications in life sciences and nanotechnologies. This article first provides a comprehensive summary of synthetic strategies towards star polymers, then reviews the latest developments in the synthesis and characterization methods of star macromolecules, and lastly outlines emerging applications and current commercial use of star-shaped polymers. The aim of this work is to promote star polymer research, generate new avenues of scientific investigation, and provide contemporary perspectives on chemical innovation that may expedite the commercialization of new star nanomaterials. We envision in the not-too-distant future star polymers will play an increasingly important role in materials science and nanotechnology in both academic and industrial settings.

Advances in Biomagnetic Interfacing Concepts Derived from Polymer-Magnetic Particle Complexes

National Research Council Canada - National Science Library

Riffle, Judy S

2005-01-01

Our research on the development and characterization of magnetic nanoparticle-polymer complexes for tile project period 6/1/03-12/31/04 has yielded approximately 10-nm diameter cobalt particles coated...

Thermoresponsive polymer micelles as potential nanosized cancerostatics

Czech Academy of Sciences Publication Activity Database

Laga, Richard; Janoušková, Olga; Ulbrich, Karel; Pola, Robert; Blažková, Jana; Filippov, Sergey K.; Etrych, Tomáš; Pechar, Michal

2015-01-01

Roč. 16, č. 8 (2015), s. 2493-2505 ISSN 1525-7797 R&D Projects: GA MŠk(CZ) EE2.3.30.0029; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61389013 Keywords : RAFT polymerization * polymer therapeutics * thermo-responsive micelles Subject RIV: CE - Biochemistry Impact factor: 5.583, year: 2015

Polymer donors of nitric oxide improve the treatment of experimental solid tumours with nanosized polymer therapeutics

Czech Academy of Sciences Publication Activity Database

Šírová, Milada; Horková, Veronika; Etrych, Tomáš; Chytil, Petr; Říhová, Blanka; Studenovský, Martin

2017-01-01

Roč. 25, 9-10 (2017), s. 796-808 ISSN 1061-186X R&D Projects: GA ČR(CZ) GA14-12742S; GA MZd(CZ) NV16-28600A Institutional support: RVO:61388971 ; RVO:61389013 Keywords : Drug delivery * HPMA copolymers * enhanced EPR effect Subject RIV: EE - Microbiology, Virology; CD - Macromolecular Chemistry (UMCH-V) OBOR OECD: Microbiology; Polymer science (UMCH-V) Impact factor: 3.068, year: 2016

New secondary batteries utilizing electronically conductive polymer cathodes

Science.gov (United States)

Martin, Charles R.; White, Ralph E.

1989-01-01

The objectives of this project are to characterize the transport properties in electronically conductive polymers and to assess the utility of these films as cathodes in lithium/polymer secondary batteries. During this research period, progress has been made in a literature survey of the historical background, methods of preparation, the physical and chemical properties, and potential technological applications of polythiophene. Progress has also been made in the characterization of polypyrrole flat films and fibrillar films. Cyclic voltammetry and potential step chronocoulometry were used to gain information on peak currents and potentials switching reaction rates, charge capacity, and charge retention. Battery charge/discharge studies were also performed.

Shape memory polymers

Energy Technology Data Exchange (ETDEWEB)

Wilson, Thomas S.; Bearinger, Jane P.

2017-08-29

New shape memory polymer compositions, methods for synthesizing new shape memory polymers, and apparatus comprising an actuator and a shape memory polymer wherein the shape memory polymer comprises at least a portion of the actuator. A shape memory polymer comprising a polymer composition which physically forms a network structure wherein the polymer composition has shape-memory behavior and can be formed into a permanent primary shape, re-formed into a stable secondary shape, and controllably actuated to recover the permanent primary shape. Polymers have optimal aliphatic network structures due to minimization of dangling chains by using monomers that are symmetrical and that have matching amine and hydroxl groups providing polymers and polymer foams with clarity, tight (narrow temperature range) single transitions, and high shape recovery and recovery force that are especially useful for implanting in the human body.

Shape memory polymers

Science.gov (United States)

Wilson, Thomas S.; Bearinger, Jane P.

2015-06-09

New shape memory polymer compositions, methods for synthesizing new shape memory polymers, and apparatus comprising an actuator and a shape memory polymer wherein the shape memory polymer comprises at least a portion of the actuator. A shape memory polymer comprising a polymer composition which physically forms a network structure wherein the polymer composition has shape-memory behavior and can be formed into a permanent primary shape, re-formed into a stable secondary shape, and controllably actuated to recover the permanent primary shape. Polymers have optimal aliphatic network structures due to minimization of dangling chains by using monomers that are symmetrical and that have matching amine and hydroxyl groups providing polymers and polymer foams with clarity, tight (narrow temperature range) single transitions, and high shape recovery and recovery force that are especially useful for implanting in the human body.

Polymers – A New Open Access Scientific Journal on Polymer Science

Directory of Open Access Journals (Sweden)

Shu-Kun Lin

2009-12-01

Full Text Available Polymers is a new interdisciplinary, Open Access scientific journal on polymer science, published by Molecular Diversity Preservation International (MDPI. This journal welcomes manuscript submissions on polymer chemistry, macromolecular chemistry, polymer physics, polymer characterization and all related topics. Both synthetic polymers and natural polymers, including biopolymers, are considered. Manuscripts will be thoroughly peer-reviewed in a timely fashion, and papers will be published, if accepted, within 6 to 8 weeks after submission. [...

Acid-base equilibria and solubility of loratadine and desloratadine in water and micellar media.

Science.gov (United States)

Popović, Gordana; Cakar, Mira; Agbaba, Danica

2009-01-15

Acid-base equilibria in homogeneous and heterogeneous systems of two antihistaminics, loratadine and desloratadine were studied spectrophotometrically in Britton-Robinson's buffer at 25 degrees C. Acidity constant of loratadine was found to be pK(a) 5.25 and those of desloratadine pK(a1) 4.41 and pK(a2) 9.97. The values of intrinsic solubilities of loratadine and desloratadine were 8.65x10(-6) M and 3.82x10(-4) M, respectively. Based on the pK(a) values and intrinsic solubilities, solubility curves of these two drugs as a function of pH were calculated. The effects of anionic, cationic and non-ionic surfactants applied in the concentration exceeding critical micelle concentration (cmc) on acid-base properties of loratadine and desloratadine, as well as on intrinsic solubility of loratadine were also examined. The results revealed a shift of pK(a) values in micellar media comparing to the values obtained in water. These shifts (DeltapK(a)) ranged from -2.24 to +1.24.

Functionalized Vegetable Oils for Utilization as Polymer Building Blocks: Office of Industrial Technologies (OIT) Agriculture Project Fact Sheet

International Nuclear Information System (INIS)

Carde, T.

2001-01-01

Vegetable oils such as soybean oil will be converted to novel polymers using hydroformylation and other catalytic processes. These polymers can be used in the construction, automotive, packaging, and electronic sectors

Polymer chemistry (revised edition)

International Nuclear Information System (INIS)

Kim, Jae Mum

1987-02-01

This book deals with polymer chemistry, which is divided into fourteen chapters. The contents of this book are development of polymer chemistry, conception of polymer, measurement of polymer chemistry, conception of polymer, measurement of polymer, molecule structure of polymer, thermal prosperities of solid polymer, basic theory of polymerization, radical polymerization, ion polymerization, radical polymerization, copolymerization, polymerization by step-reaction, polymer reaction, crown polymer and inorganic polymer on classification and process of creation such as polymeric sulfur and carbon fiber.

Integration of conducting polymer network in non-conductive polymer substrates

DEFF Research Database (Denmark)

Hansen, Thomas Steen; West, Keld; Hassager, Ole

2006-01-01

Anew method for integration ofconjugated, inherently conducting polymers into non-conductive polymer substrates has been developed. Alayer of the conducting polymer is polymerised by chemical oxidation, e.g. using Fe(ID) p-toluene sulfonate (ferri tosylate) followed by washing with a solvent which...... simultaneously removes residual and spent oxidant and at the same time dissolves the top layer of the polymer substrate. This results in an integration of the conducting polymer into the surface layers of the polymer substrate. Several combinations of conducting polymers and substrates have been tested...... absorption during sequential reactive ion etching has allowed for analysis of the PEDOT distribution within the surface layer of thePMMA substrate. The surface resistance ofthe conducting polymer layer remains low while the surface layer at the same time adapts some of the mechanical properties...

Method of improving heterogeneous oil reservoir polymer flooding effect by positively-charged gel profile control

Science.gov (United States)

Zhao, Ling; Xia, Huifen

2018-01-01

The project of polymer flooding has achieved great success in Daqing oilfield, and the main oil reservoir recovery can be improved by more than 15%. But, for some strong oil reservoir heterogeneity carrying out polymer flooding, polymer solution will be inefficient and invalid loop problem in the high permeability layer, then cause the larger polymer volume, and a significant reduction in the polymer flooding efficiency. Aiming at this problem, it is studied the method that improves heterogeneous oil reservoir polymer flooding effect by positively-charged gel profile control. The research results show that the polymer physical and chemical reaction of positively-charged gel with the residual polymer in high permeability layer can generate three-dimensional network of polymer, plugging high permeable layer, and increase injection pressure gradient, then improve the effect of polymer flooding development. Under the condition of the same dosage, positively-charged gel profile control can improve the polymer flooding recovery factor by 2.3∼3.8 percentage points. Under the condition of the same polymer flooding recovery factor increase value, after positively-charged gel profile control, it can reduce the polymer volume by 50 %. Applying mechanism of positively-charged gel profile control technology is feasible, cost savings, simple construction, and no environmental pollution, therefore has good application prospect.

Analysis of Dyes Extracted from Millimeter-Size Nylon Fibers by Micellar Electrokinetic Chromatography

International Nuclear Information System (INIS)

Lewis, L.A.

2001-01-01

The Learning Objective is to present to the forensic community a potential qualitative/quantitative method for trace-fiber color comparisons using micellar electrokinetic chromatography (MEKC). Developing a means of analyzing extracted dye constituents from millimeter-size nylon fiber samples was the objective of this research initiative. Aside from ascertaining fiber type, color evaluation and source comparison of trace-fiber evidence plays a critical role in forensic-fiber examinations. Literally thousands of dyes exist to date, including both natural and synthetic compounds. Typically a three-color-dye combination is employed to affect a given color on fiber material. The result of this practice leads to a significant number of potential dye combinations capable of producing a similar color and shade. Since a typical forensic fiber sample is 2 mm or less in length, an ideal forensic dye analysis would qualitatively and quantitatively identify the extracted dye constituents from a sample size of 1 mm or smaller. The goal of this research was to develop an analytical method for comparing individual dye constituents from trace-fiber evidence with dyes extracted from a suspected source, while preserving as much of the original evidence as possible

Influence of buffer zone concentrations on efficiency in partial filling micellar electrokinetic chromatography.

Science.gov (United States)

Michalke, D; Kolb, S; Welsch, T

2001-05-04

The potential of counter pressure-moderated partial filling micellar electrokinetic chromatography (PF-MEKC) was investigated in this work. Plate numbers of homologous omega-phenylalcohols were measured in a two-plug PF-MEKC system varying the concentrations and hence the ionic strengths of the background buffer compared to the sodium dodecyl sulfate-containing separation buffer and the counter pressure on the cathodic buffer reservoir. It was observed that plate numbers are strongly influenced by both the buffer concentrations and the counter pressure. Highest plate numbers were obtained with a buffer system where the concentrations are adjusted such that the electroosmotic flow velocities in both zones are equal. Differences in the local electroosmotic flow velocities of the zones caused by different buffer concentrations are responsible for tremendously reduced plate numbers. The efficiency drop is explained in several models by the formation of an intersegmental pressure which produces a parabolically shaped laminar flow component in both zones. Thus, the electroosmotic plug-like flow profile is distorted and the efficiency is reduced. The effect of counter pressure on efficiency turned out to be very complex in dependence on the buffer system applied.

Thin aligned organic polymer films for liquid crystal devices

International Nuclear Information System (INIS)

Foster, Kathryn Ellen

1997-01-01

This project was designed to investigate the possibility of producing alignment layers for liquid crystal devices by cross-linking thin films containing anisotropic polymer bound chromophores via irradiation with polarised ultraviolet light. Photocross-linkable polymers find use in microelectronics, liquid crystal displays, printing and UV curable lacquers and inks; so there is an increasing incentive for the development of new varieties of photopolymers in general. The synthesis and characterisation of two new photopolymers that are suitable as potential alignment layers for liquid crystal devices are reported in this thesis. The first polymer contains the anthracene chromophore attached via a spacer unit to a methacrylate backbone and the second used a similarly attached aryl azide group. Copolymers of the new monomers with methyl methacrylate were investigated to establish reactivity ratios in order to understand composition drift during polymerisation. (author)

Fluorination of polymers

International Nuclear Information System (INIS)

Du Toit, F.J.

1991-01-01

Polyethylene and polypropylene were reacted with elemental fluorine under carefully controlled conditions to produce fluorocarbon polymers. Fluorination of polymer films resulted in fluorination of only the outer surfaces of the films, while the reaction of elemental fluorine with powdered hydrocarbon polymers produced perfluorocarbon polymers. Existing and newly developed techniques were used to characterize the fluorinated polymers. It was shown that the degree of fluorination was influenced by the surface area of the hydrocarbon material, the concentration, of the fluorine gas, and the time and temperature of fluorination. A fluidized-bed reactor used for the fluorination of polymer powders effectively increased the reaction rate. The surface tension and the oxygen permeability of the fluorinated polymers were studied. The surface tension of hydrocarbon polymers was not influenced by different solvents, but the surface tension of fluorinated polymers was affected by the type of solvent that was used. There were indications that the surface tension was affected by oxygen introduced into the polymer surface during fluorination. Fluorination lowered the permeability of oxygen through hydrocarbon polymers. 55 refs., 51 figs., 26 tabs

Application of electron beam on natural polymer systems. Viscose rayon and polysaccharide derivatives

International Nuclear Information System (INIS)

Kudoh, Hisaaki

2003-01-01

Application of electron accelerator on natural polymers, viscose rayon and polysaccharide derivatives is presented. In Canada at AECL, a high-energy (10 MeV) electron linear accelerator named IMPELA was used to reduce and control molecular weight of cellulose. Recently, under UNDP/RCA/IAEA project, Asian countries had a cooperated research program on this subject. Kinetics of radiation chemistry of polysaccharide derivatives is under investigation by means of pulse radiolysis with a 35 MeV electron linear accelerator. Rate constants between polymers and hydrated electron etc., and characteristics of very long-lived polymer radical were reported. (author)

Electric field induced dewetting at polymer/polymer interfaces

NARCIS (Netherlands)

Lin, Z.Q.; Kerle, T.; Russell, T.P.; Schäffer, E.; Steiner, U

2002-01-01

External electric fields were used to amplify interfacial fluctuations in the air/polymer/polymer system where one polymer dewets the other. Two different hydrodynamic regimes were found as a function of electric field strength. If heterogeneous nucleation leads to the formation of holes before the

Biodegradation of Synthetic Polymers by Composting and Fungal Treatment

Czech Academy of Sciences Publication Activity Database

Šašek, Václav; Vitásek, J.; Chromcová, D.; Prokopová, I.; Brožek, J.; Náhlík, J.

2006-01-01

Roč. 51, č. 5 (2006), s. 425-430 ISSN 0015-5632 R&D Projects: GA ČR GA203/03/0508 Institutional research plan: CEZ:AV0Z50200510 Keywords : biodegradation * composting * synthetic polymers Subject RIV: EE - Microbiology, Virology Impact factor: 0.963, year: 2006

Photo-bleaching of polymer discoloration caused by quinone methides

Czech Academy of Sciences Publication Activity Database

Pospíšil, Jan; Nešpůrek, Stanislav; Zweifel, H.; Kuthan, J.

2002-01-01

Roč. 78, č. 2 (2002), s. 251-255 ISSN 0141-3910 R&D Projects: GA AV ČR IAA1050901 Institutional research plan: CEZ:AV0Z4050913 Keywords : quinone methide * photo- bleaching * polymer discoloration Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.145, year: 2002

All-polymer microfluidic systems for droplet based sample analysis

DEFF Research Database (Denmark)

Poulsen, Carl Esben

In this PhD project, I pursued to develop an all-polymer injection moulded microfluidic platform with integrated droplet based single cell interrogation. To allow for a proper ”one device - one experiment” methodology and to ensure a high relevancy to non-academic settings, the systems presented ...

White polymer light-emitting diode based on polymer blending

International Nuclear Information System (INIS)

Lee, Yong Kyun; Kwon, Soon Kab; Kim, Jun Young; Park, Tae Jin; Song, Dae Ho; Kwon, Jang Hyuk; Choo, Dong Jun; Jang, Jin; Jin, Jae Kyu; You, Hong

2006-01-01

A series of white polymer light emitting devices have been fabricated by using a polymer blending system of polyfluorene-based blue and MEH-PPV red polymers. A device structure of ITO/PEDOT:PSS/polymer/LiF/Al was employed. The white polymer device exhibited a current efficiency of 4.33 cd/A (4,816 cd/m 2 , Q.E. = 1.9 %) and a maximum luminance of 21,430 cd/m 2 at 9.2 V. The CIE coordinates were (0.35, 0.37) at 5 V and (0.29, 0.30) at 9 V.

Lengthening the lifetime of roll-to-roll produced polymer solar cells

DEFF Research Database (Denmark)

Madsen, Morten Vesterager

the knowledge of the degradation mechanisms involved in roll-to-roll coated polymer solar cells. While only a part of the experiments have directly involved roll-to-roll coated devices, most of the work is applicable to coated devices. The first part of the dissertation is devoted to the study of in......The field of polymer solar cells is a field with an exponential growth in the number of published papers. It is a field defined by a set of challenges including; efficiency, stability and processability. Before all of these challenges have been addressed; polymer solar cells...... will not be a commercial success. This dissertation is devoted primarily to the study of the stability of polymer solar cells, and more specifically to designing and verifying experimental techniques, procedures, and automated solutions to stability tests and characterization. The goal of the project was to expand...

Neutron- and light-scattering studies of the liquid-to-glass and glass-to-glass transitions in dense copolymer micellar solutions

International Nuclear Information System (INIS)

Chen Weiren; Chen Sowhsin; Mallamace, Francesco; Glinka, Charles J.; Fratini, Emiliano

2003-01-01

Recent mode coupling theory (MCT) calculations show that if a short-range attractive interaction is added to the pure hard sphere system, one may observe a new type of glass originating from the clustering effect (the attractive glass) as a result of the attractive interaction. This is in addition to the known glass-forming mechanism due to the cage effect in the hard sphere system (the repulsive glass). The calculations also indicate that if the range of attraction is sufficiently short compared to the diameter of the particle, within a certain interval of volume fractions where the two glass-forming mechanisms nearly balance each other, varying the external control parameter, the effective temperature, makes the glass-to-liquid-to-glass reentrance and the glass-to-glass transitions possible. Here we present experimental evidence of both transitions, obtained from small-angle neutron-scattering and photon correlation measurements taken from dense L64 copolymer micellar solutions in heavy water. Varying the temperature in certain predicted volume fraction range triggers a sharp transition between these two different types of glass. In particular, according to MCT, there is an end point (called A 3 singularity) of this glass-to-glass transition line, beyond which the long-time dynamics of the two glasses become identical. Our findings confirm this theoretical prediction. Surprisingly, although the Debye-Waller factors, the long-time limit of the coherent intermediate scattering functions, of these two glasses obtained from photon correlation measurements indeed become identical at the predicted volume fraction, they exhibit distinctly different intermediate time relaxation. Furthermore, our experimental results obtained from volume fractions beyond the end point are characterized by the same features as the repulsive glass obtained before the end point. A complete phase diagram giving the boundaries of the structural arrest transitions for L64 micellar system is

Radiation decomposition of alcohols and chloro phenols in micellar systems; Descomposicion por irradiacion de alcoholes y clorofenoles en sistemas micelares

Energy Technology Data Exchange (ETDEWEB)

Moreno A, J

1999-12-31

The effect of surfactants on the radiation decomposition yield of alcohols and chloro phenols has been studied with gamma doses of 2, 3, and 5 KGy. These compounds were used as typical pollutants in waste water, and the effect of the water solubility, chemical structure, and the nature of the surfactant, anionic or cationic, was studied. The results show that anionic surfactant like sodium dodecylsulfate (SDS), improve the radiation decomposition yield of ortho-chloro phenol, while cationic surfactant like cetyl trimethylammonium chloride (CTAC), improve the radiation decomposition yield of butyl alcohol. A similar behavior is expected for those alcohols with water solubility close to the studied ones. Surfactant concentrations below critical micellar concentration (CMC), inhibited radiation decomposition for both types of alcohols. However radiation decomposition yield increased when surfactant concentrations were bigger than the CMC. Aromatic alcohols decomposition was more marked than for linear alcohols decomposition. On a mixture of alcohols and chloro phenols in aqueous solution the radiation decomposition yield decreased with increasing surfactant concentration. Nevertheless, there were competitive reactions between the alcohols, surfactants dimers, hydroxyl radical and other reactive species formed on water radiolysis, producing a catalytic positive effect in the decomposition of alcohols. Chemical structure and the number of carbons were not important factors in the radiation decomposition. When an alcohol like ortho-chloro phenol contained an additional chlorine atom, the decomposition of this compound was almost constant. In conclusion the micellar effect depend on both, the nature of the surfactant (anionic or cationic) and the chemical structure of the alcohols. The results of this study are useful for wastewater treatment plants based on the oxidant effect of the hydroxyl radical, like in advanced oxidation processes, or in combined treatment such as

Radiation decomposition of alcohols and chloro phenols in micellar systems; Descomposicion por irradiacion de alcoholes y clorofenoles en sistemas micelares

Energy Technology Data Exchange (ETDEWEB)

Moreno A, J

1998-12-31

The effect of surfactants on the radiation decomposition yield of alcohols and chloro phenols has been studied with gamma doses of 2, 3, and 5 KGy. These compounds were used as typical pollutants in waste water, and the effect of the water solubility, chemical structure, and the nature of the surfactant, anionic or cationic, was studied. The results show that anionic surfactant like sodium dodecylsulfate (SDS), improve the radiation decomposition yield of ortho-chloro phenol, while cationic surfactant like cetyl trimethylammonium chloride (CTAC), improve the radiation decomposition yield of butyl alcohol. A similar behavior is expected for those alcohols with water solubility close to the studied ones. Surfactant concentrations below critical micellar concentration (CMC), inhibited radiation decomposition for both types of alcohols. However radiation decomposition yield increased when surfactant concentrations were bigger than the CMC. Aromatic alcohols decomposition was more marked than for linear alcohols decomposition. On a mixture of alcohols and chloro phenols in aqueous solution the radiation decomposition yield decreased with increasing surfactant concentration. Nevertheless, there were competitive reactions between the alcohols, surfactants dimers, hydroxyl radical and other reactive species formed on water radiolysis, producing a catalytic positive effect in the decomposition of alcohols. Chemical structure and the number of carbons were not important factors in the radiation decomposition. When an alcohol like ortho-chloro phenol contained an additional chlorine atom, the decomposition of this compound was almost constant. In conclusion the micellar effect depend on both, the nature of the surfactant (anionic or cationic) and the chemical structure of the alcohols. The results of this study are useful for wastewater treatment plants based on the oxidant effect of the hydroxyl radical, like in advanced oxidation processes, or in combined treatment such as

Study on application of positron lifetime spectroscopy in investigation of radiation influences on nuclear track detector polymer

International Nuclear Information System (INIS)

Khuong Thanh Tuan; Tran Dai Nghiep; Nguyen Manh Hung; Nguyen Duc Thanh; Le Anh Tuyen

2007-01-01

Study on determination of micro porosity of materials using positron lifetime technique is an advanced and promoted tendency in physics and material science presently. In Vietnam, studies in this field have been carried out by some projects funded by VAEC in recent few years, with their object is determination of porosity of oil-contained rock and polymers. This project is established to study the relationship between characteristic of positron lifetime spectra and micro porosity of polymer material, which a type of nuclear track detector made from, after irradiation. The experimental result shows a linear relation of a particular characteristic of lifetime spectra - intensity of lifetime components above 1 ns - and the density of track in polymer created by irradiation. (author)

A Study of Functional Polymer Colloids Prepared Using Thiol-Ene/Yne Click Chemistry

Science.gov (United States)

Durham, Olivia Z.

This project demonstrates the first instance of thiol-ene chemistry as the polymerization method for the production of polymer colloids in two-phase heterogeneous suspensions, miniemulsions, and emulsions. This work was also expanded to thiol-yne chemistry for the production of polymer particles containing increased crosslinking density. The utility of thiol-ene and thiol-yne chemistries for polymerization and polymer modification is well established in bulk systems. These reactions are considered 'click' reactions, which can be defined as processes that are both facile and simple, offering high yields with nearly 100% conversion, no side products, easy product separation, compatibility with a diverse variety of commercially available starting materials, and orthogonality with other chemistries. In addition, thiol-ene and thiol-yne chemistry follow a step-growth mechanism for the development of highly uniform polymer networks, where polymer growth is dependent on the coupling of functional groups. These step-growth polymerization systems are in stark contrast to the chain-growth mechanisms of acrylic and styrenic monomers that have dominated the field of conventional heterogeneous polymerizations. Preliminary studies evaluated the mechanism of particle production in suspension and miniemulsion systems. Monomer droplets were compared to the final polymer particles to confirm that particle growth occurred through the polymerization of monomer droplets. Additional parameters examined include homogenization energy (mechanical mixing), diluent species and concentration, and monomer content. These reactions were conducted using photoinitiation to yield particles in a matter of minutes with diameters in the size range of several microns to hundreds of microns in suspensions or submicron particles in miniemulsions. Improved control over the particle size and size distribution was examined through variation of reaction parameters. In addition, a method of seeded suspension

Fluorescence resonance energy transfer between perylene and riboflavin in micellar solution and analytical application on determination of vitamin B{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Bhattar, S.L.; Kolekar, G.B. [Fluorescence Spectroscopy Research Laboratory, Department of Chemistry, Shivaji University, Kolhapur 416 004, Maharashtra (India); Patil, S.R. [Fluorescence Spectroscopy Research Laboratory, Department of Chemistry, Shivaji University, Kolhapur 416 004, Maharashtra (India)], E-mail: srp_fsl@rediffmail.com

2008-03-15

Fluorescence resonance energy transfer (FRET) between perylene and riboflavin is studied in micellar solution of sodium dodecyl sulfate. The fluorescence of perylene is quenched by riboflavin and quenching is in accordance with Stern-Volmer relation. The efficiency of energy transfer is found to depend on the concentration of riboflavin. The value of critical energy transfer distance (R{sub 0}) calculated by using Foster relation is 32.13 A, and as it is less than 50 A, it indicates efficient energy transfer in the present system. The analytical relation was established between extent of sensitization and concentration of riboflavin, which helped to estimate vitamin B{sub 2} directly from pharmaceutical tablets.

Development of advanced natural polymer using radiation technology

International Nuclear Information System (INIS)

Kang, Phil Hyun; Nho, Young Chang; Jeon, Jun Pyo

2012-01-01

This project was performed to develop the environment-friendly and higher value-added materials using natural polymers derivatives from biotic-resources by radiation technology. To study for structural change of natural polymer by radiation, the effect of electron beam and Gamma ray into four kinds of plants such as Kenaf core, kenaf bast, ock and cornhusk was investigated. As results of analysis about structural change of natural polymer by radiation, efficiently separating process of Lignin was developed by improved decomposition of Lignin with increasing power of radiation. Environ-friendly separating process of Cellulose and Lignin using radiation and water-cook was developed without toxically chemical treatment. Papers were fabricated by cellulose and tensile strength of pulp fabricated by radiation was invested properties of pulp depending on power of radiation. High purity cellulose was fabricated by reduced chemical ratio between hemi-cellulose and Lignin with control of radiative power. Manufacturing process of natural paper highly containing cellulose content was developed using efficient separation of cellulose from ock tree, kenaf core and kenaf bast through radiation technique. Cellulose fiber was fabricated using separated cellulose by radiation through the drying and wetting spinning with methanol and water. Also nano-fiber with Lignin was made by electro-spinning with different ratio between PAN and Lignin. Effect of thermal treatment and carbonization of fabricated nano-fiber was invested. Carbon fiber with Lignin was applied to high value-added a secondary battery used as a cathode in half cell type. The secondary battery with carbon fiber with Lignin used as a cathode showed very efficient performance, which revealed capacity-preservation with 100% during 100 cycles. This project could significantly contribute to national competitiveness with radiation technology and Low-carbon and green-growth industrial technology, based on securement of

Quantitative correlation between counterion (X binding affinity to cationic micelles and X – Induced micellar growth for substituted iodobenzoates (X

Directory of Open Access Journals (Sweden)

Nor Saadah M. Yusof

2017-05-01

Full Text Available A new semi-empirical kinetic (SEK method has been used to calculate the values of KXBr or RXBr (X represents substituted iodobenzoates, with KX and KBr representing CTABr micellar binding constants of counterions X− (in the presence of either spherical or non-spherical micelles and Br− (in the presence of only spherical micelles, respectively. Steady-shear rheological properties of mixed 0.015 M CTABr/[MX] aqueous solutions reveal the presence of flexible wormlike micelles where MX represents sodium 3- and 4-iodobenzoates. The maxima of the plots of viscosity vs. [MX] at 0.015 M CTABr for MX representing sodium 3- and 4-iodobenzoates support the presence of long linear and entangled wormlike micelles.

The effect of caffeine on the reactions of the excited singlet state of pyrene in micellar sodium lauryl sulfate

Science.gov (United States)

Hashimoto, Shuichi; Thomas, J. Kerry

1984-08-01

The effect of caffeine on a few photo-induced reactions of pyrene in micellar sodium lauryl sulfate (NaLS) has been studied. In these systems caffeine complexes with the pyrene (K asso = 85 ± 10 M -1 and also with the other reactants, e.g. Cu 2+ or TI +. The efficiencies of reactions which involve contact, i.e. pyrene excimer formation, and quenching by TI + ions to give the triplet state of pyrene, are significantly reduced in the presence of caffeine, due to geometric inhibitions formed by the complexation processes. The kinetics of photo-induced electron transfer, e.g. between excited pyrene and Cu 2+, are not affected. However, the subsequent reactions of the products are modified and the yield of ionic products is markedly increased.

Application of controlled radiation-induced degradation in polymers: less exploited aspect of radiation processing of polymers

International Nuclear Information System (INIS)

Haji Saeid, M.; Guven, O.

2007-01-01

Industrial use of ionizing radiation treatment has been most successful in applications related to polymeric materials. The polymer, plastics and rubber industries have benefited from the unique advantages of ionizing radiation since its inception as an industrial tool to modify their properties and manufacture novel materials with value addition to the end product. The established and emerging applications of electron beam processing of polymers are based on the well known ultimate effects of ionizing radiation on polymers namely, crosslinking, curing, grafting and chain scissioning. Radiation-induced crosslinking dominates most applications, whereas the chain scissioning effect is much less explored and currently limited to radiation-induced degradation of Teflon, cellulose and polypropylene. The controlling of radiation-induced degradation for achieving a target average molecular weight or distribution has been evaluated for some polysaccharides, biopolymers and waste inner tubes whereas mitigation of the degradative effects of radiation has been analyzed from the point of view of using certain stabilizers, copolymers and annealing at an appropriate temperature. Several new or highly specialized techniques such as positron annihilation lifetime spectroscopy. Rutherford backscattering, elastic recoil detection analysis and solid waste NMR spectroscopy and gas chromatography-mass spectroscopy have been applied to the study or radiation-induced degradation. New information has been collected on the morphological changes associated with radiation-induced degradation processes, including chain scission, oxidation and free volume alteration. The IAEA coordinated research project (CRP) on Controlling of Degradation Effects in Radiation Processing of Polymers dealt with the role and importance of using ionizing radiation in controlling properties of natural and synthetic polymers through its degradative effect. This paper provides a summary of most important results

Polymer Electrolytes

Science.gov (United States)

Hallinan, Daniel T.; Balsara, Nitash P.

2013-07-01

This review article covers applications in which polymer electrolytes are used: lithium batteries, fuel cells, and water desalination. The ideas of electrochemical potential, salt activity, and ion transport are presented in the context of these applications. Potential is defined, and we show how a cell potential measurement can be used to ascertain salt activity. The transport parameters needed to fully specify a binary electrolyte (salt + solvent) are presented. We define five fundamentally different types of homogeneous electrolytes: type I (classical liquid electrolytes), type II (gel electrolytes), type III (dry polymer electrolytes), type IV (dry single-ion-conducting polymer electrolytes), and type V (solvated single-ion-conducting polymer electrolytes). Typical values of transport parameters are provided for all types of electrolytes. Comparison among the values provides insight into the transport mechanisms occurring in polymer electrolytes. It is desirable to decouple the mechanical properties of polymer electrolyte membranes from the ionic conductivity. One way to accomplish this is through the development of microphase-separated polymers, wherein one of the microphases conducts ions while the other enhances the mechanical rigidity of the heterogeneous polymer electrolyte. We cover all three types of conducting polymer electrolyte phases (types III, IV, and V). We present a simple framework that relates the transport parameters of heterogeneous electrolytes to homogeneous analogs. We conclude by discussing electrochemical stability of electrolytes and the effects of water contamination because of their relevance to applications such as lithium ion batteries.

Polymer brush-functionalized chitosan hydrogels as antifouling implant coatings

Czech Academy of Sciences Publication Activity Database

Buzzacchera, I.; Vorobii, M.; Kostina, N. Yu.; de los Santos Pereira, Andres; Riedel, Tomáš; Bruns, M.; Ogieglo, W.; Möller, M.; Wilson, C. J.; Rodriguez-Emmenegger, C.

2017-01-01

Roč. 18, č. 6 (2017), s. 1983-1992 ISSN 1525-7797 R&D Projects: GA ČR(CZ) GBP205/12/G118 Institutional support: RVO:61389013 Keywords : chitosan * hemocompatible * polymer brushes Subject RIV: CE - Biochemistry OBOR OECD: Biochemistry and molecular biology Impact factor: 5.246, year: 2016

Morphological analysis of polymer systems with broad particle size distribution

Czech Academy of Sciences Publication Activity Database

Šlouf, Miroslav; Ostafinska, Aleksandra; Nevoralová, Martina; Fortelný, Ivan

2015-01-01

Roč. 42, April (2015), s. 8-16 ISSN 0142-9418 R&D Projects: GA ČR(CZ) GA14-17921S Institutional support: RVO:61389013 Keywords : polymer blends * morphology * image analysis Subject RIV: JJ - Other Materials Impact factor: 2.350, year: 2015

Pseudo-stationary separation materials for highly parallel separations.

Energy Technology Data Exchange (ETDEWEB)

Singh, Anup K.; Palmer, Christopher (University of Montana, Missoula, MT)

2005-05-01

Goal of this study was to develop and characterize novel polymeric materials as pseudostationary phases in electrokinetic chromatography. Fundamental studies have characterized the chromatographic selectivity of the materials as a function of chemical structure and molecular conformation. The selectivities of the polymers has been studied extensively, resulting in a large body of fundamental knowledge regarding the performance and selectivity of polymeric pseudostationary phases. Two polymers have also been used for amino acid and peptide separations, and with laser induced fluorescence detection. The polymers performed well for the separation of derivatized amino acids, and provided some significant differences in selectivity relative to a commonly used micellar pseudostationary phase. The polymers did not perform well for peptide separations. The polymers were compatible with laser induced fluorescence detection, indicating that they should also be compatible with chip-based separations.

Polymer compositions, polymer films and methods and precursors for forming same

Science.gov (United States)

Klaehn, John R; Peterson, Eric S; Orme, Christopher J

2013-09-24

Stable, high performance polymer compositions including polybenzimidazole (PBI) and a melamine-formaldehyde polymer, such as methylated, poly(melamine-co-formaldehyde), for forming structures such as films, fibers and bulky structures. The polymer compositions may be formed by combining polybenzimidazole with the melamine-formaldehyde polymer to form a precursor. The polybenzimidazole may be reacted and/or intertwined with the melamine-formaldehyde polymer to form the polymer composition. For example, a stable, free-standing film having a thickness of, for example, between about 5 .mu.m and about 30 .mu.m may be formed from the polymer composition. Such films may be used as gas separation membranes and may be submerged into water for extended periods without crazing and cracking. The polymer composition may also be used as a coating on substrates, such as metal and ceramics, or may be used for spinning fibers. Precursors for forming such polymer compositions are also disclosed.

Bioenergy/Biotechnology projects

Energy Technology Data Exchange (ETDEWEB)

Napper, Stan [Louisiana Tech Univ., Ruston, LA (United States); Palmer, James [Louisiana Tech Univ., Ruston, LA (United States); Wilson, Chester [Louisiana Tech Univ., Ruston, LA (United States); Guilbeau, Eric [Louisiana Tech Univ., Ruston, LA (United States); Allouche, Erez [Louisiana Tech Univ., Ruston, LA (United States)

2012-06-30

This report describes the progress of five different projects. The first is an enzyme immobilization study of cellulase to reduce costs of the cellulosic ethanol process. High reusability and use of substrates applicable to large scale production were focus areas for this study. The second project was the development of nanostructured catalysts for conversion of syngas to diesel. Cobalt nanowire catalyst was used in Fischer-Tropsch synthesis. The third project describes work on developing a microfluidic calorimeter to measure reaction rates of enzymes. The fourth project uses inorganic polymer binders that have the advantage of a lower carbon footprint than Portland cement while also providing excellent performance in elevated temperature, high corrosion resistance, high compressive and tensile strengths, and rapid strength gains. The fifth project investigates the potential of turbines in drop structures (such as sewer lines in tall buildings) to recover energy.

Novel Ceramic-Polymer Composite Membranes for the Separation of Hazardous Liquid Waste

Energy Technology Data Exchange (ETDEWEB)

Yoram Cohen

2001-12-01

The present project was conceived to address the need for robust yet selective membranes suitable for operating in harsh ph, solvent, and temperature environments. An important goal of the project was to develop a membrane chemical modification technology that would allow one to tailor-design membranes for targeted separation tasks. The method developed in the present study is based on the process of surface graft polymerization. Using essentially the same base technology of surface modification the research was aimed at demonstrating that improved membranes can be designed for both pervaporation separation and ultrafiltration. In the case of pervaporation, the present study was the first to demonstrate that pervaporation can be achieved with ceramic support membranes modified with an essentially molecular layer of terminally anchored polymer chains. The main advantage of the above approach, relative to other proposed membranes, is that the separating polymer layer is covalently attached to the ceramic support. Therefore, such membranes have a potential use in organic-organic separations where the polymer can swell significantly yet membrane robustness is maintained due to the chemical linkage of the chains to be inorganic support. The above membrane technology was also useful in developing fouling resistant ultrafiltration membranes. The prototype membrane developed in the project was evaluated for the treatment of oil-in-water microemulsions, demonstrating lack of irreversible fouling common with commercial membranes.

Semi-empirical spectrophotometric (SESp) method for the indirect determination of the ratio of cationic micellar binding constants of counterions X⁻ and Br⁻(K(X)/K(Br)).

Science.gov (United States)

Khan, Mohammad Niyaz; Yusof, Nor Saadah Mohd; Razak, Norazizah Abdul

2013-01-01

The semi-empirical spectrophotometric (SESp) method, for the indirect determination of ion exchange constants (K(X)(Br)) of ion exchange processes occurring between counterions (X⁻ and Br⁻) at the cationic micellar surface, is described in this article. The method uses an anionic spectrophotometric probe molecule, N-(2-methoxyphenyl)phthalamate ion (1⁻), which measures the effects of varying concentrations of inert inorganic or organic salt (Na(v)X, v = 1, 2) on absorbance, (A(ob)) at 310 nm, of samples containing constant concentrations of 1⁻, NaOH and cationic micelles. The observed data fit satisfactorily to an empirical equation which gives the values of two empirical constants. These empirical constants lead to the determination of K(X)(Br) (= K(X)/K(Br) with K(X) and K(Br) representing cationic micellar binding constants of counterions X and Br⁻). This method gives values of K(X)(Br) for both moderately hydrophobic and hydrophilic X⁻. The values of K(X)(Br), obtained by using this method, are comparable with the corresponding values of K(X)(Br), obtained by the use of semi-empirical kinetic (SEK) method, for different moderately hydrophobic X. The values of K(X)(Br) for X = Cl⁻ and 2,6-Cl₂C6H₃CO₂⁻, obtained by the use of SESp and SEK methods, are similar to those obtained by the use of other different conventional methods.

Development of quinoxaline based polymers for photovoltaic applications

Czech Academy of Sciences Publication Activity Database

Yuan, J.; Ouyang, J.; Cimrová, Věra; Leclerc, M.; Najari, A.; Zou, Y.

2017-01-01

Roč. 5, č. 8 (2017), s. 1858-1879 ISSN 2050-7526 R&D Projects: GA ČR(CZ) GA13-26542S Institutional support: RVO:61389013 Keywords : conjugated polymers * quinoxaline based * photovoltaic s Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 5.256, year: 2016

One-electron redox potentials and rate of electron transfer in aqueous micellar solution. Partially solubilized quinones

International Nuclear Information System (INIS)

Almgren, M.; Grieser, F.; Thomas, J.K.

1979-01-01

The electron transfer equilibrium between AQS/AQS - and DQ/DQ - (where AQS is sodium 9,10-arthraquinone-2-sulfonate and DQ, duroquinone) has been studied by pulse radiolysis in aqueous micellar solutions of sodium lauryl sulfate. The equilibrium constant is changed as would be expected if AQS, AQS - , and DQ- were all mainly in the aqueous solution, and DQ distributed between the micelles and the aqueous phase with a distribution constant of K/sub D//N = 150 M -1 , in agreement with the independently determined value of this constant. The kinetics of the equilibration show, however, that electron transfer at the micelle surface is important, indicating that also AQS and DQ - are associated with the micelle to some extent. With reasonable assumptions regarding the distribution constants of these species (that have some independent support), the observed catalytic effect of the micelles on the electron transfer from DQ - to AQS can be understood

Environmental monitoring of phenolic pollutants in water by cloud point extraction prior to micellar electrokinetic chromatography.

Science.gov (United States)

Stege, Patricia W; Sombra, Lorena L; Messina, Germán A; Martinez, Luis D; Silva, María F

2009-05-01

Many aromatic compounds can be found in the environment as a result of anthropogenic activities and some of them are highly toxic. The need to determine low concentrations of pollutants requires analytical methods with high sensitivity, selectivity, and resolution for application to soil, sediment, water, and other environmental samples. Complex sample preparation involving analyte isolation and enrichment is generally necessary before the final analysis. The present paper outlines a novel, simple, low-cost, and environmentally friendly method for the simultaneous determination of p-nitrophenol (PNP), p-aminophenol (PAP), and hydroquinone (HQ) by micellar electrokinetic capillary chromatography after preconcentration by cloud point extraction. Enrichment factors of 180 to 200 were achieved. The limits of detection of the analytes for the preconcentration of 50-ml sample volume were 0.10 microg L(-1) for PNP, 0.20 microg L(-1) for PAP, and 0.16 microg L(-1) for HQ. The optimized procedure was applied to the determination of phenolic pollutants in natural waters from San Luis, Argentina.

Development and validation of micellar liquid chromatographic methods for the determination of antibiotics in different matrixes.

Science.gov (United States)

Rambla-Alegre, Maria; Esteve-Romero, Josep; Carda-Broch, Samuel

2011-01-01

Antibiotics are the most important bioactive and chemotherapeutic compounds to be produced by microbiological synthesis, and they have proved their worth in a variety of fields, such as medicinal chemistry, agriculture, and the food industry. Interest in antibiotics has grown in parallel with an increasingly high degree of productivity in the field of analytical applications. Therefore, it is necessary to develop chromatographic procedures capable of determining various drugs simultaneously in the shortest possible time. Micellar liquid chromatography (MLC) is an RP-HPLC technique that offers advantages over conventional HPLC as far as sample preparation, selectivity, and versatility are concerned. Its main advantage is that samples can be injected directly into the chromatographic system with no previous preparation step. This paper mainly focuses on the results of the authors' own recent research and reports the chromatographic conditions for determination of various antibiotics (penicillins, quinolones, and sulfonamides) in different matrixes (pharmaceuticals, biological fluids, and food). The work of other authors on MLC-based antibiotic determination has been included.

Polymer and Polymer Gel of Liquid Crystalline Semiconductors

Institute of Scientific and Technical Information of China (English)

Teppei Shimakawa; Naoki Yoshimoto; Jun-ichi Hanna

2004-01-01

It prepared a polymer and polymer gel of a liquid crystalline (LC) semiconductor having a 2-phenylnaphthalene moiety and studied their charge carrier transport properties by the time-of-flight technique. It is found that polyacrylate having the mesogenic core moiety of 2-phenylnaphtalene (PNP-acrylate) exhibited a comparable mobility of 10-4cm2/Vs in smectic A phase to those in smectic A (SmA) phase of small molecular liquid crystals with the same core moiety, e.g., 6-(4'-octylphenyl)- 2-dodecyloxynaphthalene (8-PNP-O12), and an enhanced mobility up to 10-3cm2/Vs in the LC-glassy phase at room temperature, when mixed with a small amount of 8-PNP-O12. On the other hand, the polymer gel consisting of 20 wt %-hexamethylenediacrylate (HDA)-based cross-linked polymer and 8-PNP-O12 exhibited no degraded mobility when cross-linked at the mesophase. These results indicate that the polymer and polymer composite of liquid crystalline semiconductors provide us with an easy way to realize a quality organic semiconductor thin film for the immediate device applications.

In silico modelling of drug–polymer interactions for pharmaceutical formulations

Science.gov (United States)

Ahmad, Samina; Johnston, Blair F.; Mackay, Simon P.; Schatzlein, Andreas G.; Gellert, Paul; Sengupta, Durba; Uchegbu, Ijeoma F.

2010-01-01

Selecting polymers for drug encapsulation in pharmaceutical formulations is usually made after extensive trial and error experiments. To speed up excipient choice procedures, we have explored coarse-grained computer simulations (dissipative particle dynamics (DPD) and coarse-grained molecular dynamics using the MARTINI force field) of polymer–drug interactions to study the encapsulation of prednisolone (log p = 1.6), paracetamol (log p = 0.3) and isoniazid (log p = −1.1) in poly(l-lactic acid) (PLA) controlled release microspheres, as well as the encapsulation of propofol (log p = 4.1) in bioavailability enhancing quaternary ammonium palmitoyl glycol chitosan (GCPQ) micelles. Simulations have been compared with experimental data. DPD simulations, in good correlation with experimental data, correctly revealed that hydrophobic drugs (prednisolone and paracetamol) could be encapsulated within PLA microspheres and predicted the experimentally observed paracetamol encapsulation levels (5–8% of the initial drug level) in 50 mg ml−1 PLA microspheres, but only when initial paracetamol levels exceeded 5 mg ml−1. However, the mesoscale technique was unable to model the hydrophilic drug (isoniazid) encapsulation (4–9% of the initial drug level) which was observed in experiments. Molecular dynamics simulations using the MARTINI force field indicated that the self-assembly of GCPQ is rapid, with propofol residing at the interface between micellar hydrophobic and hydrophilic groups, and that there is a heterogeneous distribution of propofol within the GCPQ micelle population. GCPQ–propofol experiments also revealed a population of relatively empty and drug-filled GCPQ particles. PMID:20519214

Phototriggered functionalization of hierarchically structured polymer brushes

Czech Academy of Sciences Publication Activity Database

de los Santos Pereira, Andres; Kostina, Nina Yu.; Bruns, M.; Rodriguez-Emmenegger, Cesar; Barner-Kowollik, C.

2015-01-01

Roč. 31, č. 21 (2015), s. 5899-5907 ISSN 0743-7463 R&D Projects: GA ČR(CZ) GJ15-09368Y; GA MŠk(CZ) ED1.1.00/02.0109 Grant - others:OPPK(XE) CZ.2.16/3.1.00/21545 Program:OPPK Institutional support: RVO:61389013 Keywords : polymer brushes * antifouling * click chemistry Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.993, year: 2015

Antifouling polymer brushes displaying antithrombogenic surface properties

Czech Academy of Sciences Publication Activity Database

de los Santos Pereira, Andres; Sheikh, S.; Blaszykowski, C.; Pop-Georgievski, Ognen; Fedorov, K.; Thompson, M.; Rodriguez-Emmenegger, Cesar

2016-01-01

Roč. 17, č. 3 (2016), s. 1179-1185 ISSN 1525-7797 R&D Projects: GA ČR(CZ) GJ15-09368Y; GA MŠk(CZ) ED1.1.00/02.0109 Grant - others:OPPK(XE) CZ.2.16/3.1.00/21545 Program:OPPK Institutional support: RVO:61389013 Keywords : polymer brushes * surface characterization * antifouling surfaces Subject RIV: BO - Biophysics Impact factor: 5.246, year: 2016

Proton-conducting polymer electrolytes based on methacrylates

Czech Academy of Sciences Publication Activity Database

Reiter, Jakub; Velická, Jana; Míka, M.

2008-01-01

Roč. 53, č. 26 (2008), s. 7769-7774 ISSN 0013-4686 R&D Projects: GA ČR GA106/04/1279; GA AV ČR KJB400320701; GA MŠk LC523; GA ČR(CZ) GA104/06/1471 Institutional research plan: CEZ:AV0Z40320502 Keywords : polymer electrolyte * proton conductivity * phosporic acid Subject RIV: CA - Inorganic Chemistry Impact factor: 3.078, year: 2008

Mechanical Behavior of Polymer Nano Bio Composite for Orthopedic Implants

Science.gov (United States)

Marimuthu, K., Dr.; Rajan, Sankar

2018-04-01

The bio-based polymer composites have been the focus of many scientific and research projects, as well as many commercial programs. In recent years, scientists and engineers have been working together to use the inherent strength and performance of the new class of bio-based composites which is compactable with human body and can act as a substitute for living cells. In this stage the polymer composites also stepped into human bone implants as a replacement for metallic implants which was problems like corrosion resistance and high cost. The polymer composite have the advantage that it can be molded to the required shape, the polymers have high corrosion resistance, less weight and low cost. The aim of this research is to develop and analyze the suitable bio compactable polymer composite for human implants. The nano particles reinforced polymer composites provides good mechanical properties and shows good tribological properties especially in the total hip and knee replacements. The graphene oxide powders are bio compactable and acts as anti biotic. GO nano powder where reinforced into High-density polyethylene in various weight percentage of 0.5% to 2%. The performance of GO nano powder shows better tribological properties. The material produced does not cause any pollution to the environment and at the same time it can be bio compactable and sustainable. The product will act environmentally friendly.

Sequential optimization of methotrexate encapsulation in micellar nano-networks of polyethyleneimine ionomer containing redox-sensitive cross-links

Directory of Open Access Journals (Sweden)

Abolmaali SS

2014-06-01

Full Text Available Samira Sadat Abolmaali,1 Ali Tamaddon,1,2 Gholamhossein Yousefi,1,2 Katayoun Javidnia,3 Rasoul Dinarvand41Department of Pharmaceutics, Shiraz School of Pharmacy, 2Center for Nanotechnology in Drug Delivery, 3Medicinal and Natural Products Chemistry Research Center, Shiraz University of Medical Sciences, Shiraz, Iran; 4Nanotechnology Research Centre, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, IranAbstract: A functional polycation nanonetwork was developed for delivery of water soluble chemotherapeutic agents. The complexes of polyethyleneimine grafted methoxy polyethylene glycol (PEI-g-mPEG and Zn2+ were utilized as the micellar template for cross-linking with dithiodipropionic acid, followed by an acidic pH dialysis to remove the metal ion from the micellar template. The synthesis method was optimized according to pH, the molar ratio of Zn2+, and the cross-link ratio. The atomic force microscopy showed soft, discrete, and uniform nano-networks. They were sensitive to the simulated reductive environment as determined by Ellman's assay. They showed few positive ζ potential and an average hydrodynamic diameter of 162±10 nm, which decreased to 49±11 nm upon dehydration. The ionic character of the nano-networks allowed the achievement of a higher-loading capacity of methotrexate (MTX, approximately 57% weight per weight, depending on the cross-link and the drug feed ratios. The nano-networks actively loaded with MTX presented some suitable properties, such as the hydrodynamic size of 117±16 nm, polydispersity index of 0.22, and a prolonged swelling-controlled release profile over 24 hours that boosted following reductive activation of the nanonetwork biodegradation. Unlike the PEI ionomer, the nano-networks provided an acceptable cytotoxicity profile. The drug-loaded nano-networks exhibited more specific cytotoxicity against human hepatocellular carcinoma cells if compared to free MTX at concentrations above 1 µM. The

High Thermal Conductivity Polymer Composites for Low Cost Heat Exchangers

Energy Technology Data Exchange (ETDEWEB)

None

2017-08-01

This factsheet describes a project that identified and evaluated commercially available and state-of-the-art polymer-based material options for manufacturing industrial and commercial non-metallic heat exchangers. A heat exchanger concept was also developed and its performance evaluated with heat transfer modeling tools.

One-step Preparation of Antimicrobial Silver Nanoparticles in Polymer Matrix.

Czech Academy of Sciences Publication Activity Database

Lyutakov, O.; Kalachyova, Y.; Solovyev, Andrey; Vytykačová, S.; Švanda, J.; Siegel, J.; Ulbrich, P.; Švorčík, V.

2015-01-01

Roč. 17, č. 3 (2015), s. 120 ISSN 1388-0764 R&D Projects: GA ČR(CZ) GBP108/12/G108 Institutional support: RVO:67985858 Keywords : polymer * silver nanoparticles * antimicrobial test Subject RIV: JJ - Other Materials Impact factor: 2.101, year: 2015

Passive tumor targeting of polymer therapeutics: in vivo imaging of both the polymer carrier and the enzymatically cleavable drug model

Czech Academy of Sciences Publication Activity Database

Pola, Robert; Heinrich, A. K.; Mueller, T.; Kostka, Libor; Mäder, K.; Pechar, Michal; Etrych, Tomáš

2016-01-01

Roč. 16, č. 11 (2016), s. 1577-1582 ISSN 1616-5187 R&D Projects: GA ČR(CZ) GA15-02986S; GA ČR(CZ) GA16-17207S; GA MŠk(CZ) LO1507 Institutional support: RVO:61389013 Keywords : polymer drug carriers * tumor targeting * enzymatic release Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.238, year: 2016

Avidin-conjugated polymers with monobiotinylated antibody fragments: a new strategy for the noncovalent attachment of recombinant proteins for polymer therapeutics

Czech Academy of Sciences Publication Activity Database

Laga, Richard; Pola, Robert; Ulbrich, Karel; Hořejší, Magdalena; Sieglová, Irena; Král, Vlastimil; Fábry, Milan; Pechar, Michal

2013-01-01

Roč. 28, č. 3 (2013), s. 289-299 ISSN 0883-9115 R&D Projects: GA ČR GCP207/12/J030; GA AV ČR IAAX00500803 Institutional research plan: CEZ:AV0Z50520514 Institutional support: RVO:61389013 ; RVO:68378050 Keywords : avidin-biotin complex * polymer therapeutics * drug targeting Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.500, year: 2013

All-Polymer Microfluidic Systems with integrated Nanostructures for Cell Handling

DEFF Research Database (Denmark)

Matschuk, Maria

There is an increasing need for mass-production of nanostructures with high precision at polymer surfaces, for example to reduce the reflection of light, to reduce the adhesion of smudge, for optical data storage (e.g. Blu-ray discs), and for biological applications. In this project the effects...... of the polymer melt, interfacial effects like wetting and friction play a major role in injection molding of high aspect ratio nanostructures. The interfacial energy between mold and polymer needs to allow filling as well as demolding which are opposing properties: On the one hand, insufficient wetting...... cavity during demolding leading to nanostructural failure. It was found that the mold temperature has a major influence on the replication depth for tested mold coatings while other parameters (melt temperature, injection velocity and pressure, holding pressure and ejection temperature) do not have any...

Dihydroxybenzene/benzoquinone-containing polymers: organic redox polymers

Energy Technology Data Exchange (ETDEWEB)

Moulay, S. [Universite de Blida, Lab. de Chimie-Physique Macromoleculaire, Institut de Chimie Industrielle (Algeria)

2000-08-01

Polymers containing hydroquinone, catechol or their corresponding benzoquinones are a special class of redox polymers. Three pathways of their syntheses are possible: condensation polymerization of suitable monomers, addition polymerization of vinyl monomers containing redox moiety, and chemical attachment of redox unit onto pre-made polymeric matrix. A range of functionalized matrices have been employed such as polyethers, polyesters, polycarbonates, polyurethanes, polyamides and others. Protection of their phenolic functionality has conducted to chemically interesting redox polymer precursors. The presence of a redox moiety coupled with the extant functionalization of the polymer matrix makes the materials very valuable, of wide properties and consequently of vast applicability. For instance, in the oil field, some polymers such as carboxy-methyl-cellulose (CMC) are often applied as to bring about a viscosity improvement and therefore to facilitate the oil drilling. In this regard, Patel evaluated sulfo-alkylated polymeric catechol, namely sulfo-methylated and sulfo-ethylated resins. Indeed, polymeric catechol chemically modified as such exhibited a marked ability to control the viscosity, the gel strength, as well as the filtrate loss of aqueous oil drilling fluids.

Kinetics and mechanism of the cutinase-catalyzed transesterification of oils in AOT reversed micellar system.

Science.gov (United States)

Badenes, Sara M; Lemos, Francisco; Cabral, Joaquim M S

2011-11-01

The kinetics of the enzymatic transesterification between a mixture of triglycerides (oils) and methanol for biodiesel production in a bis(2-ethylhexyl) sodium sulfosuccinate (AOT)/isooctane reversed micellar system, using recombinant cutinase from Fusarium solani pisi as a catalyst, was investigated. In order to describe the results that were obtained, a mechanistic scheme was proposed, based on the literature and on the experimental data. This scheme includes the following reaction steps: the formation of the active enzyme-substrate complex, the addition of an alcohol molecule to the complex followed by the separation of a molecule of the fatty acid alkyl ester and a glycerol moiety, and release of the active enzyme. Enzyme inhibition and deactivation effects due to methanol and glycerol were incorporated in the model. This kinetic model was fitted to the concentration profiles of the fatty acid methyl esters (the components of biodiesel), tri-, di- and monoglycerides, obtained for a 24 h transesterification reaction performed in a stirred batch reactor under different reaction conditions of enzyme and initial substrates concentration.

High-density arrays of titania nanoparticles using monolayer micellar films of diblock copolymers as templates.

Science.gov (United States)

Li, Xue; Lau, King Hang Aaron; Kim, Dong Ha; Knoll, Wolfgang

2005-05-24

Highly dense arrays of titania nanoparticles were fabricated using surface micellar films of poly(styrene-block-2-vinylpyridine) diblock copolymers (PS-b-P2VP) as reaction scaffolds. Titania could be introduced selectively within P2VP nanodomains in PS-b-P2VP films through the binary reaction between water molecules trapped in the P2VP domains and the TiCl(4) vapor precursors. Subsequent UV exposure or oxygen plasma treatment removed the organic matrix, leading to titania nanoparticle arrays on the substrate surface. The diameter of the titania domains and the interparticle distance were defined by the lateral scale present in the microphase-separated morphology of the initial PS-b-P2VP films. The typical diameter of titania nanoparticles obtained by oxygen plasma treatment was of the order of approximately 23 nm. Photoluminescence (PL) properties were investigated for films before and after plasma treatment. Both samples showed PL properties with major physical origin due to self-trapped excitons, indicating that the local environment of the titanium atoms is similar.

Method for bonding a thermoplastic polymer to a thermosetting polymer component

NARCIS (Netherlands)

Van Tooren, M.J.L.

2012-01-01

The invention relates to a method for bonding a thermoplastic polymer to a thermosetting polymer component, the thermoplastic polymer having a melting temperature that exceeds the curing temperature of the thermosetting polymer. The method comprises the steps of providing a cured thermosetting

On the structure of etched ion tracks in polymers

Czech Academy of Sciences Publication Activity Database

Hnatowicz, Vladimír; Vacík, Jiří; Apel, P. Yu.

2016-01-01

Roč. 121, APR (2016), s. 106-109 ISSN 0969-806X R&D Projects: GA ČR(CZ) GBP108/12/G108; GA MŠk(CZ) LM2011019 Institutional support: RVO:61389005 Keywords : polymers * ion tracks * track etching Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.315, year: 2016

Suppressing Pseudomonas aeruginosa adhesion via non-fouling polymer brushes

Czech Academy of Sciences Publication Activity Database

Rodriguez-Emmenegger, Cesar; Decker, A.; Surman, František; Preuss, C. M.; Sedláková, Zdeňka; Zydziak, N.; Barner-Kowollik, C.; Schwartz, T.; Barner, L.

2014-01-01

Roč. 4, č. 110 (2014), s. 64781-64790 ISSN 2046-2069 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0109; GA ČR GAP106/12/1451 Institutional support: RVO:61389013 Keywords : polymer brushes * tissue engineering * biology Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.840, year: 2014

Ion-conducting lithium bis(oxalato)borate-based polymer electrolytes

Czech Academy of Sciences Publication Activity Database

Reiter, Jakub; Dominko, R.; Nádherná, Martina; Jakubec, Ivo

2009-01-01

Roč. 189, č. 1 (2009), s. 133-138 ISSN 0378-7753 R&D Projects: GA MŠk LC523; GA AV ČR KJB400320701 Institutional research plan: CEZ:AV0Z40320502 Keywords : polymer electrolyte * 2-ethoxyethyl methacrylate * lithium -ion battery Subject RIV: CG - Electrochemistry Impact factor: 3.792, year: 2009

Polymer Brushes

NARCIS (Netherlands)

Vos, de W.M.; Kleijn, J.M.; Keizer, de A.; Cosgrove, T.; Cohen Stuart, M.A.

2010-01-01

A polymer brush can be defined as a dense array of polymers end-attached to an interface that stretch out into the surrounding medium. Polymer brushes have been investigated for the past 30 years and have shown to be an extremely useful tool to control interfacial properties. This review is intended

Entangled Polymer Melts in Extensional Flow: Synthesis, Rheology, Neutron Scattering

DEFF Research Database (Denmark)

Dorokhin, Andriy

This thesis contains 5 chapters and reprints in Appendices, combined of both published and unpublished materials. The first chapter is an introduction to the goals, methods and problem identification of the project of the entangled polymer melts in extensional flow, which is aimed to shed some li...

Micellar Liquid Chromatographic Determination of Carbaryl and 1-Naphthol in Water, Soil, and Vegetables

Directory of Open Access Journals (Sweden)

Mei-Liang Chin-Chen

2012-01-01

Full Text Available A liquid chromatographic procedure has been developed for the determination of carbaryl, a phenyl-N-methylcarbamate, and its main metabolite 1-naphthol, using a C18 column (250’mm’ × ’4.6’mm with a micellar mobile phase and fluorescence detection at maximum excitation/emission wavelengths of 225/333’nm, respectively. In the optimization step, surfactants sodium dodecyl sulphate (SDS, Brij-35 and N-cetylpyridinium chloride monohydrate, and organic solvents propanol, butanol, and pentanol were considered. The selected mobile phase was 0.15’M SDS-6% (v/v-pentanol-0.01’M NaH2PO4 buffered at pH 3. Validation studies, according to the ICH Tripartite Guideline, included linearity (r>0.999, limit of detection (5 and 18’ng mL-1, for carbaryl and 1-naphthol, resp., and limit of quantification (15 and 50’ng mL-1, for carbaryl and 1-naphthol, resp., with intra- and interday precisions below 1%, and robustness parameters below 3%. The results show that the procedure was adequate for the routine analysis of these two compounds in water, soil, and vegetables samples.

Origin of shear thickening in semidilute wormlike micellar solutions and evidence of elastic turbulence

International Nuclear Information System (INIS)

Marín-Santibáñez, Benjamín M.; Pérez-González, José; Rodríguez-González, Francisco

2014-01-01

The origin of shear thickening in an equimolar semidilute wormlike micellar solution of cetylpyridinium chloride and sodium salicylate was investigated in this work by using Couette rheometry, flow visualization, and capillary Rheo-particle image velocimetry. The use of the combined methods allowed the discovery of gradient shear banding flow occurring from a critical shear stress and consisting of two main bands, one isotropic (transparent) of high viscosity and one structured (turbid) of low viscosity. Mechanical rheometry indicated macroscopic shear thinning behavior in the shear banding regime. However, local velocimetry showed that the turbid band increased its viscosity along with the shear stress, even though barely reached the value of the viscosity of the isotropic phase. This shear band is the precursor of shear induced structures that subsequently give rise to the average increase in viscosity or apparent shear thickening of the solution. Further increase in the shear stress promoted the growing of the turbid band across the flow region and led to destabilization of the shear banding flow independently of the type of rheometer used, as well as to vorticity banding in Couette flow. At last, vorticity banding disappeared and the flow developed elastic turbulence with chaotic dynamics

Microtome Sliced Block Copolymers and Nanoporous Polymers as Masks for Nanolithography

DEFF Research Database (Denmark)

Shvets, Violetta; Schulte, Lars; Ndoni, Sokol

2014-01-01

Introduction. Block copolymers self-assembling properties are commonly used for creation of very fine nanostructures [1]. Goal of our project is to test new methods of the block-copolymer lithography mask preparation: macroscopic pieces of block-copolymers or nanoporous polymers with cross...... PDMS can be chemically etched from the PB matrix by tetrabutylammonium fluoride in tetrahydrofuran and macroscopic nanoporous PB piece is obtained. Both block-copolymer piece and nanoporous polymer piece were sliced with cryomicrotome perpendicular to the axis of cylinder alignment and flakes...... of etching patterns appear only under the certain parts of thick flakes and are not continuous. Although flakes from block copolymer are thinner and more uniform in thickness than flakes from nanoporous polymer, quality of patterns under nanoporous flakes appeared to be better than under block copolymer...

Preparation of PEO/Clay Nanocomposites Using Organoclay Produced via Micellar Adsorption of CTAB

Science.gov (United States)

Gürses, Ahmet; Ejder-Korucu, Mehtap; Doğar, Çetin

2012-01-01

The aim of this study was the preparation of polyethylene oxide (PEO)/clay nanocomposites using organoclay produced via micellar adsorption of cethyltrimethyl ammonium bromide (CTAB) and their characterisation by X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) spectra, and the investigation of certain mechanical properties of the composites. The results show that the basal distance between the layers increased with the increasing CTAB/clay ratio as parallel with the zeta potential values of particles. By considering the aggregation number of CTAB micelles and interlayer distances of organo-clay, it could be suggested that the predominant micelle geometry at lower CTAB/clay ratios is an ellipsoidal oblate, whereas, at higher CTAB/clay ratios, sphere-ellipsoid transition occurs. The increasing tendency of the exfoliation degree with an increase in clay content may be attributed to easier diffusion of PEO chains to interlayer regions. FT-IR spectra show that the intensity of Si-O stretching vibrations of the organoclays (1050 cm−1) increased, especially in the ratios of 1.0 g/g clay and 1.5 g/g clay with the increasing CTAB content. It was observed that the mechanical properties of the composites are dependent on both the CTAB/clay ratios and clay content of the composites. PMID:23365515

Biodistribution of a radiolabelled thermoresponsive polymer in mice

Czech Academy of Sciences Publication Activity Database

Kučka, Jan; Hrubý, Martin; Lebeda, Ondřej

2010-01-01

Roč. 68, č. 6 (2010), s. 1073-1078 ISSN 0969-8043 R&D Projects: GA ČR GPP207/10/P054; GA MŠk 2B06165 Institutional research plan: CEZ:AV0Z10480505; CEZ:AV0Z40500505 Keywords : Thermoresponsive polymer * I-131 * Local radiotherapy Subject RIV: FR - Pharmacology ; Medidal Chemistry Impact factor: 0.999, year: 2010

New bioerodable thermoresponsive polymers for possible radiotherapeutic applications

Czech Academy of Sciences Publication Activity Database

Hrubý, Martin; Kučka, Jan; Lebeda, Ondřej; Macková, Hana; Babič, Michal; Koňák, Čestmír; Studenovský, Martin; Sikora, Antonín; Kozempel, Ján; Ulbrich, Karel

2007-01-01

Roč. 119, č. 1 (2007), s. 25-33 ISSN 0168-3659 R&D Projects: GA AV ČR IAA400480616; GA AV ČR IAA100500501; GA AV ČR KAN200200651 Institutional research plan: CEZ:AV0Z40500505; CEZ:AV0Z10480505 Keywords : thermoresponsive * polymer * drug delivery Subject RIV: CD - Macromolecular Chemistry Impact factor: 4.756, year: 2007

Microwave-assisted synthesis and micellization behavior of soy-based copoly(2-oxazoline)s.

Science.gov (United States)

Hoogenboom, Richard; Leenen, Mark A M; Huang, Haiying; Fustin, Charles-André; Gohy, Jean-François; Schubert, Ulrich S

2006-01-01

Polymers based on renewable resources are promising candidates for replacing common organic polymers, and thus, for reducing oil consumption. In this contribution we report the microwave-assisted synthesis of block and statistical copolymers from 2-ethyl-2-oxazoline and 2-"soy alkyl"-2-oxazoline via a cationic ring-opening polymerization mechanism. The synthesized copolymers were characterized by gel permeation chromatography and 1 H-NMR spectroscopy. The micellization of these amphiphilic copolymers was investigated by dynamic light scattering and atomic force microscopy to examine the effect of hydrophobic block length and monomer distribution on the resulting micellar characteristics.

Antiviral Polymer Therapeutics

DEFF Research Database (Denmark)

Smith, Anton Allen Abbotsford

2014-01-01

polymerized in a controlled manner with carrier monomers of historically proven biocompatible polymers. The carrier polymers, the loading of ribavirin as well as the size of the polymer were varied systematically with the aid of an automated synthesis platform. These polymers were tested in a cellular assay...... of reversible-addition-fragmentation chain transfer polymerization, which not only controls the size of polymer, but also allows the introduction of a terminal amine on the polymer which can be used for further conjugation. This has allowed for not only fluorescent labeling of the polymer, but also protein...... is mediated through specific transporters, it is thought that the accumulation can be alleviated through the attachment of ribavirin to a macromolecule. To this end, ribavirin was enzymatically modified into a monomer compatible with controlled polymerization techniques. The ribavirin monomers were...

Solubilisation des hydrocarbures dans les solutions micellaires Influence de la structure et de la masse moléculaire Solubilization of Hydrocarbons in Micellar Solutions Influence of Structure and Molecular Weight

Directory of Open Access Journals (Sweden)

Baviere M.

2006-11-01

(paraffines, résines, asphaltènes sur les propriétés interfaciales, d'une part avec le brut de Daqing, pour effectuer des essais complémentaires, d'autre part avec des constituants modèles en solution dans un solvant approprié. Optimizing the formulation of micellar surfactant solutions used for enhanced oil recovery consists in obtaining interfacial tensions that are as low as possible in multiphase systems resulting from the mixing of the injected solution with formation fluids. The solubilization of hydrocarbons by the micellar phases of such systems is linked directly to the interfacial efficiency of surfactants. Indeed, as has been shown by numerous research projects such as the one by Reed and Healy [1], the amount of hydrocarbons solubilized by the surfactant is all the greater as the interfacial tension between the micellar phase and the hydrocarbons is low. This solubilization depends in particular, although to a great extent, on the nature of the hydrocarbons or, for the processes we are concerned with here, of the hydrocarbon mixtures encountered [181. Likewise, the criteria generally used in applying the process to a reservoir may also be fulfilled (temperature, salinity of the water, viscosity of the oil, nature and permeability of the rock, whereas the chemical nature of the oil turns out to be responsible for very mediocre efficiency. Hence this insufficiency of criteria is revealed for relatively heavy oils such as the oil in the Daqing field in China, for which production may still depend on this recovery method, a priori. The solubilization of this oil by the surfactants normally used is extremely reduced and may perhaps even by almost nil. This particularly unfavorable behavior has brought out the need of specifying selection criteria for fields from the standpoint of the nature of the oil, so as to be able to assess the quality of a crude oil and to detect possible difficulties in applying the process-diff iculties linked to the composition of the

Micro fabrication of biodegradable polymer drug delivery devices

DEFF Research Database (Denmark)

Nagstrup, Johan

The pharmaceutical industry is presently facing several obstacles in developing oral drug delivery systems. This is primarily due to the nature of the discovered drug candidates. The discovered drugs often have poor solubility and low permeability across the gastro intestinal epithelium. Furtherm......The pharmaceutical industry is presently facing several obstacles in developing oral drug delivery systems. This is primarily due to the nature of the discovered drug candidates. The discovered drugs often have poor solubility and low permeability across the gastro intestinal epithelium...... permeability and degradation. These systems are for the majority based on traditional materials used in micro technology, such as SU-8, silicon, poly(methyl methacrylate). The next step in developing these new drug delivery systems is to replace classical micro fabrication materials with biodegradable polymers....... In order to successfully do this, methods for fabricating micro structures in biodegradable polymers need to be developed. The goal of this project has been to develop methods for micro fabrication in biodegradable polymers and to use these methods to produce micro systems for oral drug delivery. This has...

Polymer/silicate well treatment techniques: state-of-art and experiences at the AlgyoeField, Hungary

Energy Technology Data Exchange (ETDEWEB)

Lakatos, I.; Lakatos-Szabo, J. [Miskolc Univ. (Hungary). Resarch Inst. of Applied Chemistry; Troemboeczky, S.; Munkacsi, I.; Kosztin, B.; Palasthy, G. [Hungarian Oil and Gas Company, Szolnok (Hungary). Upstream Div.

2000-04-01

By joint application of silicates and polymers, a multifunctional, self-controlling chemical system is formed which works spontaneously even under harsh reservoir conditions, meanwhile the methods remain inexpensive, flexible and adaptable to any production technologies. A concise summary of the technique, its principle and main field projects are discussed in this article. It is shown that the silicates, combined with polymers offer unique opportunity to cure numerous production/injection problems including water shutt-off, profile correction, gas coning, etc. in oil and gas fields. Between 1980 and 1998 the field projects, comprising more than forty well treatments, yielded substantial additional oil production, life time of wells were extended and the overall profitability of the field was significantly increased, meanwhile environmentally friendly chemicals were used. Therefore, the Hungarian experts are convinced that the polymer/silicate method is reasonable alternative wherever and whenever the application of bulk or surface gelation or deposition is arising. (orig.)

Development of Gel Polymer Electrolytes Using Radiation for Lithium Secondary Batteries

Energy Technology Data Exchange (ETDEWEB)

Park, Jung Ki; Lee, Jun Young; Lee, Dong Jin [KAIST, Daejeon (Korea, Republic of)

2010-05-15

Recently, demands of high performance lithium battery are increased. Development of battery materials for high power, high capacity, high safety are also needed. This project deals with the new gel polymer electrolyte based on the microporous matrix with specific functions using radiation techniques.

The coiled coil motif in polymer drug delivery systems

Czech Academy of Sciences Publication Activity Database

Pechar, Michal; Pola, Robert

2013-01-01

Roč. 31, č. 1 (2013), s. 90-96 ISSN 0734-9750 R&D Projects: GA ČR GA203/08/0543; GA MŠk 1M0505 Institutional research plan: CEZ:AV0Z40500505 Keywords : coiled coil * hydrophilic polymer * recombinant protein Subject RIV: CD - Macromolecular Chemistry Impact factor: 8.905, year: 2013

Vapor-Liquid Equilibrium in Diluted Polymer plus Solvent Systems

Czech Academy of Sciences Publication Activity Database

Bogdanić, Grozdana; Wichterle, Ivan

2011-01-01

Roč. 56, č. 4 (2011), s. 1080-1083 ISSN 0021-9568 R&D Projects: GA ČR GA104/07/0444 Grant - others:MZOŠ(HR) 061-0000000-3029 Institutional research plan: CEZ:AV0Z40720504 Keywords : polymer * prediction * total pressure Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.693, year: 2011

Ability of polymer-bound P-glycoprotein inhibitor ritonavir to overcome multidrug resistance in various resistant neuroblastoma cell lines

Czech Academy of Sciences Publication Activity Database

Koziolová, Eva; Chytil, Petr; Etrych, Tomáš; Janoušková, Olga

2017-01-01

Roč. 28, č. 10 (2017), s. 1126-1130 ISSN 0959-4973 R&D Projects: GA MŠk(CZ) LO1507 Institutional support: RVO:61389013 Keywords : drug-delivery polymers * multidrug resistance * N-(2-hydroxypropyl) methacrylamide Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 2.320, year: 2016

Nanoporous polymer electrolyte

Science.gov (United States)

Elliott, Brian [Wheat Ridge, CO; Nguyen, Vinh [Wheat Ridge, CO

2012-04-24

A nanoporous polymer electrolyte and methods for making the polymer electrolyte are disclosed. The polymer electrolyte comprises a crosslinked self-assembly of a polymerizable salt surfactant, wherein the crosslinked self-assembly includes nanopores and wherein the crosslinked self-assembly has a conductivity of at least 1.0.times.10.sup.-6 S/cm at 25.degree. C. The method of making a polymer electrolyte comprises providing a polymerizable salt surfactant. The method further comprises crosslinking the polymerizable salt surfactant to form a nanoporous polymer electrolyte.

Petroleum recovery process utilizing formaldehyde-sulfite-reacted polyacrylamide

Energy Technology Data Exchange (ETDEWEB)

Norton, C.J.; Falk, D.O.

1973-09-25

Micellar slugs followed by thickened water floods were injected into Berea cores (20.4 percent porosity, 398.4 md permeability, see Patent 3,692,113 for pretreatment) for enhanced oil recovery. About 61.1 percent residual oil was produced when the polymer in the thickened water was sulfomethylated hydrolyzed polyacrylamide. However, use of the conventional unhydrolyzed polyacrylamide recovered only 27.7 percent residual oil.

Industrialisation of polymer solar cells. Phase 2: Consolidation

DEFF Research Database (Denmark)

Lauritzen, Hanne; Gevorgyan, Suren; Frausig, Jesper

of the OPV devices – targets that are import both for niche applications and bulk power production. Besides the work dedicated to solving these three key targets, two more activities have been included in the project; a pre-study on OPV solar parks and an evaluation of the business opportunities arising......The present report refers to the project “Industrialization of polymer solar cells – phase 2”. Both the project and this report build directly upon the prior phase 1 where the basic OPV technology, ProcessOne, was transferred to Mekoprint. This second phase focuses on an anchoring......-scale power production. The project represents thus a crossroad, where Mekoprint and DTU gradually differentiate themselves with respect to applications and therefore also their R&D priorities. The key targets of phase 2 relate to production cost, stabilization of the production and operational lifetime...

Non-uniformity of phase structure in immiscible polymer blends

Czech Academy of Sciences Publication Activity Database

Fortelný, Ivan; Lapčíková, Monika; Lednický, František; Starý, Zdeněk; Kruliš, Zdeněk

2008-01-01

Roč. 48, č. 3 (2008), s. 564-571 ISSN 0032-3888 R&D Projects: GA ČR GA106/06/0729; GA ČR GA106/06/0761 Institutional research plan: CEZ:AV0Z40500505 Keywords : polymer blends * melt mixing * non-uniform morphology Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.245, year: 2008

Diamond growth on copper rods from polymer composite nanofibres

Czech Academy of Sciences Publication Activity Database

Varga, Marián; Potocký, Štěpán; Tesárek, P.; Babchenko, Oleg; Davydova, Marina; Kromka, Alexander

2014-01-01

Roč. 312, SEP (2014), s. 220-225 ISSN 0169-4332 R&D Projects: GA ČR(CZ) GBP108/12/G108 Institutional support: RVO:68378271 Keywords : linear antenna MWCVD * diamond * copper * polymer nanofibres Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.711, year: 2014 http://www.sciencedirect.com/science/article/pii/S0169433214011003

New coupling strategy for radionuclide labeling of synthetic polymers

Czech Academy of Sciences Publication Activity Database

Hrubý, Martin; Kučka, Jan; Nováková, Michaela; Macková, Hana; Vetrík, Miroslav

2010-01-01

Roč. 68, č. 2 (2010), s. 334-339 ISSN 0969-8043 R&D Projects: GA AV ČR KAN200200651; GA ČR GA202/09/2078; GA MŠk 1M0505 Institutional research plan: CEZ:AV0Z40500505 Keywords : polymer * radionuclide * labeling Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.999, year: 2010

Fourier-transform infrared spectroscopic study of a fractional-complexed polymer blend

Czech Academy of Sciences Publication Activity Database

Šturcová, Adriana; Kratochvíl, Jaroslav; Dybal, Jiří; Sikora, Antonín

2014-01-01

Roč. 59, October (2014), s. 200-207 ISSN 0014-3057 R&D Projects: GA ČR GAP108/12/0703 Institutional support: RVO:61389013 Keywords : miscible blend * inter-polymer complex * associative phase separation Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.005, year: 2014

Concept of polymer alloy electrolytes: towards room temperature operation of lithium-polymer batteries

International Nuclear Information System (INIS)

Noda, Kazuhiro; Yasuda, Toshikazu; Nishi, Yoshio

2004-01-01

Polymer alloy technique is very powerful tool to tune the ionic conductivity and mechanical strength of polymer electrolyte. A semi-interpenetrating polymer network (semi-IPN) polymer alloy electrolyte, composed of non-cross-linkable siloxane-based polymer and cross-linked 3D network polymer, was prepared. Such polymer alloy electrolyte has quite high ionic conductivity (more than 10 -4 Scm -1 at 25 o C and 10 -5 Scm -1 at -10 o C) and mechanical strength as a separator film with a wide electrochemical stability window. A lithium metal/semi-IPN polymer alloy solid state electrolyte/LiCoO 2 cell demonstrated promising cycle performance with room temperature operation of the energy density of 300Wh/L and better rate performance than conventional PEO based lithium polymer battery ever reported

Nanoscale Reinforced, Polymer Derived Ceramic Matrix Coatings

Energy Technology Data Exchange (ETDEWEB)

Rajendra Bordia

2009-07-31

The goal of this project was to explore and develop a novel class of nanoscale reinforced ceramic coatings for high temperature (600-1000 C) corrosion protection of metallic components in a coal-fired environment. It was focused on developing coatings that are easy to process and low cost. The approach was to use high-yield preceramic polymers loaded with nano-size fillers. The complex interplay of the particles in the polymer, their role in controlling shrinkage and phase evolution during thermal treatment, resulting densification and microstructural evolution, mechanical properties and effectiveness as corrosion protection coatings were investigated. Fe-and Ni-based alloys currently used in coal-fired environments do not possess the requisite corrosion and oxidation resistance for next generation of advanced power systems. One example of this is the power plants that use ultra supercritical steam as the working fluid. The increase in thermal efficiency of the plant and decrease in pollutant emissions are only possible by changing the properties of steam from supercritical to ultra supercritical. However, the conditions, 650 C and 34.5 MPa, are too severe and result in higher rate of corrosion due to higher metal temperatures. Coating the metallic components with ceramics that are resistant to corrosion, oxidation and erosion, is an economical and immediate solution to this problem. Good high temperature corrosion protection ceramic coatings for metallic structures must have a set of properties that are difficult to achieve using established processing techniques. The required properties include ease of coating complex shapes, low processing temperatures, thermal expansion match with metallic structures and good mechanical and chemical properties. Nanoscale reinforced composite coatings in which the matrix is derived from preceramic polymers have the potential to meet these requirements. The research was focused on developing suitable material systems and

Generalized polymer effective charge measurement by capillary isotachophoresis

Czech Academy of Sciences Publication Activity Database

Chamieh, J.; Koval, Dušan; Besson, A.; Kašička, Václav; Cottet, H.

2014-01-01

Roč. 1370, Nov 28 (2014), s. 255-262 ISSN 0021-9673 R&D Projects: GA ČR(CZ) GA13-17224S; GA MŠk 7AMB12FR012 Grant - others:GA AV ČR(CZ) M200551207 Institutional support: RVO:61388963 Keywords : polymer effective charge * polyelectrolyte * isotachophoresis * counter-ion condensation * capillary electrophoresis Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 4.169, year: 2014

Comparative experiments on polymer degradation technique of produced water of polymer flooding oilfield

Science.gov (United States)

Chen, Rong; Qi, Mei; Zhang, Guohui; Yi, Chenggao

2018-02-01

The application of polymer flooding technology in oilfields can result in polymer content increased in produced water. This increasing made produced water quality become poor. The efficiency of produced water processing decreased significantly. Processed water quality seriously exceeded criterion’s stipulation. The presence of the polymer in produced water is the main reason for more difficulties in processing of produced water, therefore the polymer degradation technology is a key coefficient in produced water processing for polymer flooding oilfields. We evaluated several physical and chemical polymer degradation methods with the solution of separated water from polymer flooding oilfields and hydrolyzed polyacrylamide. The experiment results can provide a basis for produced water processing technologies application in polymer flooding oilfields.

Printable, Degradable, and Biocompatible Ion Gels from a Renewable ABA Triblock Polyester and a Low Toxicity Ionic Liquid

Energy Technology Data Exchange (ETDEWEB)

Tang, Boxin; Schneiderman, Deborah K.; Bidoky, Fazel Zare; Frisbie, C.Daniel; Lodge, Timothy P. (UMM)

2017-09-15

We have designed printable, biocompatible, and degradable ion gels by combining a novel ABA triblock aliphatic polyester, poly(ε-decalactone)-b-poly(dl-lactide)-b-poly(ε-decalactone), and a low toxicity ionic liquid, 1-butyl-1-methylpyrrolidinium bistrifluoromethanesulfonylimide ([P14][TFSI]). Due to the favorable compatibility between amorphous poly(dl-lactide) and [P14][TFSI] and the insolubility of the poly(ε-decalactone), the triblock polymer forms self-assembled micellar cross-links similar to thermoplastic elastomers, which ensures similar processing conditions and mechanical robustness during the fabrication of printed electrolyte-gated organic transistor devices. Additionally, the ester backbone in the polymer structure enables efficient hydrolytic degradation of these ion gels compared to those made previously using carbon-backbone polymers.

Polymer blends of poly(2-cyanoethyl vinyl ether) and poly(methyl methacrylate) with improved dielectric properties for flexible electronics

Czech Academy of Sciences Publication Activity Database

Piana, Francesco; Kredatusová, Jana; Paruzel, Bartosz; Pfleger, Jiří

2017-01-01

Roč. 11, č. 9 (2017), s. 731-737 ISSN 1788-618X R&D Projects: GA MŠk(CZ) LO1507 Institutional support: RVO:61389013 Keywords : polymer blends and alloys * dielectric properties * differential scanning calorimetry Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 2.983, year: 2016

Approaches for Making High Performance Polymer Materials from Commodity Polymers

Institute of Scientific and Technical Information of China (English)

Xu Xi

2004-01-01

A brief surrey of ongoing research work done for improving and enhancing the properties of commodity polymers by the author and author's colleagues is given in this paper. A series of high performance polymers and polymer nanomaterials were successfully prepared through irradiation and stress-induced reactions of polymers and hydrogen bonding. The methods proposed are viable, easy in operation, clean and efficient.1. The effect of irradiation source (UV light, electron beam, γ -ray and microwave), irradiation dose, irradiation time and atmosphere etc. on molecular structure of polyolefine during irradiation was studied. The basic rules of dominating oxidation, degradation and cross-linking reactions were mastered. Under the controlled conditions, cross-linking reactions are prevented, some oxygen containing groups are introduced on the molecular chain of polyolefine to facilitate the interface compatibility of their blends. A series of high performance polymer materials: u-HDPE/PA6,u-HDPE/CaCO3, u-iPP/STC, γ-HDPE/STC, γ-LLDPE/ATH, e-HDPE, e-LLDPE and m-HDPEfilled system were prepared (u- ultraviolet light irradiated, γ- γ-ray irradiated, e- electron beam irradiated, m- microwave irradiated)2. The effect of ultrasonic irradiation, jet and pan-milling on structure and changes in properties of polymers were studied. Imposition of critical stress on polymer chain can cause the scission of bonds to form macroradicals. The macroradicals formed in this way may recombine or react with monomer or other radicals to form linear, branched or cross-linked polymers or copolymers. About 20 kinds of block/graft copolymers have been synthesized from polymer-polymer or polymer-monomer through ultrasonic irradiation.Through jet-milling, the molecular weight of PVC is decreased somewhat, the intensity of its crystalline absorption bonds becomes indistinct. The processability, the yield strength, strength at break and elongation at break of PVC get increased quite a lot after

U.S. Department of Energy's initiatives for proliferation prevention in Russia: results of radioactive liquid waste treatment project, year 2

International Nuclear Information System (INIS)

Pokhitonov, Y.; Kamachev, V.; Kelley, D.

2010-10-01

The objective of the project is to engage weapons scientists with training and research programs at selected nuclear sites in Russia and apply high technology polymers to immobilize legacy ILW and HLW liquids that have posed environmental challenges over the years. One compelling advantage of the projects is that V.G. Khlopin Radium Institute and Pacific Nuclear Solutions have been engaged in applied research for seven years to validate the performance and effectiveness of the polymer technology for use with radioactive liquids. With conclusive results of the research work on sixty active and simulant waste streams, the project can focus on actual applications of the technology at Ozersk (Mayak), Sever sk (SCC) Zheleznogorsk (MCC) and Gatchyna rather that on pure research. The long term objective of the project is find viable waste management solutions for serious radioactive and chemical contamination that has existed in Russia and the U. S. for several decades. The polymer technologies may be applied to all radioactive liquid. This paper summarizes the experimental work of the immobilization process and data definition of the most effective polymer compositions in addition to determining the optimum polymer to liquid ratios for economic considerations. (Author)

Physical Properties of Polymers (Ultrastructure Processing of Polymers)

Science.gov (United States)

1982-09-30

vinyl benzene Network-Diluent Systems". 17. J . Appl. Polym. Sci. 28, 219-224 (1983) (with R. Vukovic and W.J. MacKnight) "Compatibility of Some...Temperature of Polymer Networks by Dil uents". 23. J . Appl. Polym. Sci. 28, 1379-1389 (1983) (with R. Vukovic , V. Kuresevic, N. Segudovic, and W.J...AFOSR 80-0101 IV. DATES: 1 January 1980 - 30 September 1982 V. SENIOR RESEARCH PERSONNEL*: Dr. C. Crosby Dr. G. ten Brinke Dr. T. Ellis Dr. R. Vukovic

Microwave synthesis: An alternative approach to synthesize conducting end-capped polymers

Czech Academy of Sciences Publication Activity Database

Marcasuzaa, P.; Reynaud, S.; Grassl, B.; Preud’homme, H.; Desbrieres, J.; Trchová, Miroslava; Donard, O. F. X.

2011-01-01

Roč. 52, č. 1 (2011), s. 33-39 ISSN 0032-3861 Grant - others:Eco-net project (FR) 16256SA Institutional research plan: CEZ:AV0Z40500505 Keywords : tetra-aniline * microwave synthesis * intrinsically conducting polymers Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.438, year: 2011

Supramolecular micellar nanoaggregates based on a novel chitosan/vitamin E succinate copolymer for paclitaxel selective delivery

Directory of Open Access Journals (Sweden)

Lian H

2011-12-01

Full Text Available He Lian1, Jin Sun1, Yan Ping Yu1, Yan Hua Liu2, Wen Cao1, Yong Jun Wang1, Ying Hua Sun1, Si Ling Wang1, Zhong Gui He11School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, 2Department of Pharmaceutics, School of Pharmacy, Ningxia Medical University, Ningxia, People's Republic of ChinaBackground: Nowadays, many cytotoxic anticancer drugs exhibit low solubility and poor tumor selectivity, which means that the drug formulation is very important. For example, in the case of paclitaxel (PTX, Cremophor EL® (BASF, Ludwigshafen, Germany needs to be used as a solubilizer in its clinical formulation (Taxol®, Bristol-Myers Squibb, New York, NY, although it can cause serious side effects. Nanomicellar systems are promising carriers to resolve the above problems, and the polymer chosen is the key element.Methods: In this study, a novel amphiphilic chitosan/vitamin E succinate (CS-VES copolymer was successfully synthesized for self-assembling polymeric micelles. Proton nuclear magnetic resonance spectroscopy and infrared were used to characterize the molecular structure of the copolymer. The PTX-loaded CS-VES polymeric micelles (PTX-micelles were characterized by dynamic light scattering, transmission electron microscopy, X-ray diffraction, and differential scanning calorimetry.Results: The critical micelle concentration of CS-VES was about 12.6 µg/mL, with the degree of amino group substitution being 20.4%. PTX-micelles were prepared by a nanoprecipitation/dispersion technique without any surfactant being involved. PTX-micelles exhibited a drug loading as high as 21.37% and an encapsulation efficiency of 81.12%, with a particle size ranging from 326.3 to 380.8 nm and a zeta potential of +20 mV. In vitro release study showed a near zero-order sustained release, with 51.06%, 50.88%, and 44.35% of the PTX in the micelles being released up to 168 hours at three drug loadings of 7.52%, 14.09%, and 21.37%, respectively. The cellular uptake

[New polymer-drug systems based on natural and synthetic polymers].

Science.gov (United States)

Racoviţă, Stefania; Vasiliu, Silvia; Foia, Liliana

2010-01-01

The great versatility of polymers makes them very useful in the biomedical and pharmaceutical fields. The combination of natural and synthetic polymers leads to new materials with tailored functional properties. The aim of this work consists in the preparation of new drug delivery system based on chitosan (natural polymer) and polybetaines (synthetic polymers), by a simple process, well known in the literature as complex coacervation methods. Also, the adsorption and release studies of two antibiotics as well as the preservation of their bactericidal capacities were performed.

Reprotonation of aniline: A route to various conducting polymer materials

Czech Academy of Sciences Publication Activity Database

Stejskal, Jaroslav; Prokeš, B.; Trchová, Miroslava

2008-01-01

Roč. 68, č. 9 (2008), s. 1355-1361 ISSN 1381-5148 R&D Projects: GA ČR GA202/06/0419; GA ČR GA203/08/0686 Institutional research plan: CEZ:AV0Z40500505 Keywords : acids * conductivity * conducting polymer Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.039, year: 2008

A New Prediction Method for Organic Liquids Sorption into Polymers

Czech Academy of Sciences Publication Activity Database

Randová, A.; Bartovská, L.; Izák, Pavel; Friess, K.

2015-01-01

Roč. 475, FEB 1 (2015), s. 545-551 ISSN 0376-7388 R&D Projects: GA ČR(CZ) GAP106/12/0569; GA MŠk(CZ) LD14094 Institutional support: RVO:67985858 Keywords : organic liquids * liquid non-solvents * polymers Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 5.557, year: 2015

The Recent Developments in Biobased Polymers toward General and Engineering Applications: Polymers that Are Upgraded from Biodegradable Polymers, Analogous to Petroleum-Derived Polymers, and Newly Developed

OpenAIRE

Nakajima, Hajime; Dijkstra, Peter; Loos, Katja

2017-01-01

The main motivation for development of biobased polymers was their biodegradability, which is becoming important due to strong public concern about waste. Reflecting recent changes in the polymer industry, the sustainability of biobased polymers allows them to be used for general and engineering applications. This expansion is driven by the remarkable progress in the processes for refining biomass feedstocks to produce biobased building blocks that allow biobased polymers to have more versati...

Application of temperature responsive polymers for water recovery from mineral tailings

Energy Technology Data Exchange (ETDEWEB)

Franks, G.; O' Shea, J.P.; Qiao, G. [Melbourne Univ., Melbourne (Australia). Australian Mineral Science Research Inst.; Li, H. [Alberta Research Council, Edmonton, AB (Canada)

2008-07-01

The Australian Mineral Science Research Institute ((AMSRI) was built in 2005 as a collaborative research project between industry and academic researchers in Australia. Conventional flocculants produce inter-particle attraction that causes aggregation, rapid sedimentation, and high moisture levels in resulting cakes and sediments. This presentation described a study conducted at the AMSRI to evaluate stimulus responsive flocculation processes for dewatering. Stimuli included pH and temperature. Polymers used in the experiments included non-ionic polymers (PNIPAM) cationic co-polymers (CPNIPAM) and cationic polyacrylamide (PAM). Silica powder, kaolinite, and alumina powder settling results with PNIPAM at 22 degrees and 50 degrees C were investigated. Kaolinite settling results at 22 and 50 degrees C were also investigated. Supernatants at 22 and 50 degrees C were compared. Alumina settling results with PNIPAMs were tested at different charge densities. The effects of non-ionic PNIPAM on water clarity were also evaluated. Results of the study showed that all processes developed in the study have the potential for improving water recovery and reducing the volume of oil sands tailings. Solids flocculation and consolidation appeared to be possible using only a single polymer. It was concluded that polymer performance depends on molecular weight, dosage, and charge density. tabs., figs.

Determination of strobilurin fungicide residues in fruits and vegetables by micellar electrokinetic capillary chromatography with sweeping.

Science.gov (United States)

Wang, Kun; Chen, Guan-hua; Wu, Xian; Shi, Jie; Guo, Dong-shan

2014-02-01

A new assay of micellar electrokinetic capillary chromatography with sweeping was developed to determine azoxystrobin, kresoxim-methyl and pyraclostrobin in fruits and vegetables. The key factors affecting resolution and peak height were studied and the optimum conditions were obtained for separation and enrichment. The running buffer consisted of 40 mM borate, 25 mM sodium dodecyl sulfate and 15% acetonitrile, and its pH was adjusted to 8.4. The sample was injected for 677 nL and the separation voltage was 25 kV. Under the optimum conditions, the enrichment factors of azoxystrobin, kresoxim-methyl and pyraclostrobin were 861, 550 and 403; the linear dynamic ranges were all 0.01-5.0 mg/L; the limits of detection were 0.002, 0.001 and 0.002 mg/kg; the recoveries of spiked samples were 85.1-98.5%, 87.5-97.0% and 89.1-99.1%, respectively. The assay can meet the requirement of maximum residue limits for these three strobilurin fungicides, and has been applied for determining their residues in fruits and vegetables.

Synthesis and antibacterial activity of water-dispersible silver nanoparticles via micellar nanoreactors

Science.gov (United States)

Pofali, Prasad; Shirolikar, Seema; Borde, Lalit; Pattani, Aditya; Dandekar, Prajakta; Jain, Ratnesh

2018-04-01

We have synthesized silver nanoparticles (AgNPs) using micelles of sugar fatty acid ester by dissolving the surfactant in a mixture of iso-octane and n-butanol, with solid-liquid extraction. Highly concentrated, water-dispersible AgNPs were obtained after thorough washing with alcohol, to remove excess of sucrose fatty acid ester DK SS and salt, followed by drying. The particles were characterized for their size, morphology and crystallinity using UV-Visible spectrophotometry, Transmission Electron Microscopy and x-ray diffractometry. Antibacterial study, confirmed the activity of nanoparticles against E. coli, P. aeruginosa and S. aureus, which causes diseases including diarrhoea and several life-threatening infections. Antibacterial activity of E. coli and P. aeruginosa was found to be 2.5 fold and for S. aureus 1.6 fold compared to 50 ppm conc. of Silver Nitrate. Our method of producing nanoparticles is employed as a platform technology for synthesizing other inorganic nanoparticles. This is the first report discussing the use of micellar carriers for obtaining silver nanopowder, to the best of our knowledge, which has the potential to overcome limitations during fabrication of AgNPs using reverse/inverse micelles. Our method yielded nano-sized, water-dispersible AgNPs via an easy and economic approach. The one-pot approach possesses advantages in terms of cost and simplicity, as compared with traditional methods of producing powdered AgNPs using energy intensive and expensive techniques like lyophilisation. The developed method, thus, possesses immense potential for commercial synthesis of AgNPs.

Polymer containing functional end groups is base for new polymers

Science.gov (United States)

Hirshfield, S. M.

1971-01-01

Butadiene is polymerized with lithium-p-lithiophenoxide to produce linear polymer containing oxy-lithium group at one end and active carbon-lithium group at other end. Living polymers represent new approach to preparation of difunctional polymers in which structural features, molecular weight, type and number of end groups are controlled.

Suspensions of polymer-grafted nanoparticles with added polymers-Structure and effective pair-interactions.

Science.gov (United States)

Chandran, Sivasurender; Saw, Shibu; Kandar, A K; Dasgupta, C; Sprung, M; Basu, J K

2015-08-28

We present the results of combined experimental and theoretical (molecular dynamics simulations and integral equation theory) studies of the structure and effective interactions of suspensions of polymer grafted nanoparticles (PGNPs) in the presence of linear polymers. Due to the absence of systematic experimental and theoretical studies of PGNPs, it is widely believed that the structure and effective interactions in such binary mixtures would be very similar to those of an analogous soft colloidal material-star polymers. In our study, polystyrene-grafted gold nanoparticles with functionality f = 70 were mixed with linear polystyrene (PS) of two different molecular weights for obtaining two PGNP:PS size ratios, ξ = 0.14 and 2.76 (where, ξ = Mg/Mm, Mg and Mm being the molecular weights of grafting and matrix polymers, respectively). The experimental structure factor of PGNPs could be modeled with an effective potential (Model-X), which has been found to be widely applicable for star polymers. Similarly, the structure factor of the blends with ξ = 0.14 could be modeled reasonably well, while the structure of blends with ξ = 2.76 could not be captured, especially for high density of added polymers. A model (Model-Y) for effective interactions between PGNPs in a melt of matrix polymers also failed to provide good agreement with the experimental data for samples with ξ = 2.76 and high density of added polymers. We tentatively attribute this anomaly in modeling the structure factor of blends with ξ = 2.76 to the questionable assumption of Model-X in describing the added polymers as star polymers with functionality 2, which gets manifested in both polymer-polymer and polymer-PGNP interactions especially at higher fractions of added polymers. The failure of Model-Y may be due to the neglect of possible many-body interactions among PGNPs mediated by matrix polymers when the fraction of added polymers is high. These observations point to the need for a new framework to

Repair of impact damaged utility poles with fiber reinforced polymers (FRP), phase II.

Science.gov (United States)

2015-06-01

Vehicle collisions with steel or aluminum utility poles are common occurrences that yield substantial but often repairable : damage. This project investigates the use of a fiber-reinforced polymer (FRP) composite system for in situ repair that : mini...

Removal and recovery of toxic metal ions from aqueous waste sites using polymer pendant ligands

International Nuclear Information System (INIS)

Fish, D.

1996-01-01

The purpose of this project is to investigate the use of polymer pendant ligand technology to remove and recover toxic metal ions from DOE aqueous waste sites. Polymer pendant lgiands are organic ligands, anchored to crosslinked, modified divinylbenzene-polystyrene beads, that can selectively complex metal ions. The metal ion removal step usually occurs through a complexation or ion exchange phenomena, thus recovery of the metal ions and reuse of the beads is readily accomplished

Synthesis and evaluation of tetramethylguanidinium-polyethylenimine polymers as efficient gene delivery vectors.

Science.gov (United States)

Mahato, Manohar; Yadav, Santosh; Kumar, Pradeep; Sharma, Ashwani Kumar

2014-01-01

Previously, we demonstrated that 6-(N,N,N',N'-tetramethylguanidinium chloride)-hexanoyl-polyethylenimine (THP) polymers exhibited significantly enhanced transfection efficiency and cell viability. Here, in the present study, we have synthesized a series of N,N,N',N'-tetramethylguanidinium-polyethylenimine (TP1-TP5) polymers via a single-step reaction involving peripheral primary amines of bPEI and varying amounts of 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate (HBTU). These polymers were found to interact efficiently with negatively charged pDNA and formed stable complexes in the size range of ~240-450 nm. Acid-base titration profiles revealed improved buffering capacity of TP polymers as compared to bPEI. Transfection and cytotoxicity assays performed with TP/pDNA complexes on HEK293, CHO, and HeLa cells showed significantly higher transfection efficiency and cell viability with one of the complexes, TP2/pDNA complex, exhibited the highest transfection efficiency (~1.4-2.3-fold) outcompeting native bPEI and the commercially available transfection reagent, Lipofectamine 2000. Compared to previously reported THP polymers, the transfection efficiency of TP/pDNA complexes was found to be lower, as examined by flow cytometry. These results highlight the importance of the hydrophobic C-6 linker in THP polymers in forming compact nanostructures with pDNA, which might lead to efficient uptake and internalization of the complexes; however, the projected TP polymers offer an advantage of their rapid and economical one-step synthesis.

The Recent Developments in Biobased Polymers toward General and Engineering Applications : Polymers that Are Upgraded from Biodegradable Polymers, Analogous to Petroleum-Derived Polymers, and Newly Developed

NARCIS (Netherlands)

Nakajima, Hajime; Dijkstra, Peter; Loos, Katja

2017-01-01

The main motivation for development of biobased polymers was their biodegradability, which is becoming important due to strong public concern about waste. Reflecting recent changes in the polymer industry, the sustainability of biobased polymers allows them to be used for general and engineering

Numerical Modeling of Macroscopic Behavior of Particulate Composite with Crosslinked Polymer Matrix

Czech Academy of Sciences Publication Activity Database

Náhlík, Luboš; Máša, B.; Hutař, Pavel

2011-01-01

Roč. 465, - (2011), s. 129-132 ISSN 1013-9826 R&D Projects: GA ČR GA106/08/1409 Institutional research plan: CEZ:AV0Z20410507 Keywords : Particle reinforced composites * polymer matrix composite * mechanical response Subject RIV: JI - Composite Materials

Physico-chemistry characterization of sulfonated polyacrylamide polymers for use in polymer flooding

Energy Technology Data Exchange (ETDEWEB)

Rashidi, Masoud

2010-07-01

Hydrolyzed polyacrylamide polymer (HPAM) as a feasible and effective viscosifier has been fully studied and used for polymer flooding processes in several oil field, e.g. Daqing oil field. It has been shown that Hydrolyzed polyacrylamide polymers (HPAM) may be a good choice for high temperature condition with no oxygen and no divalent ions presence. At high temperature and high salinity conditions, polymer may precipitates and loss their viscosyfing properties. Also adsorption and retention of polymer in porous medium may change rheological properties of polymers. Thus, the viscosyfing property of polymers is influenced by several important parameters, e.g. salinity, hardness, temperature, adsorption, retention, polymer structure, and etc. By replacing some of carboxylate group of HPAM with another monomer, e.g. sodium salt of acrylic acid and 2-acrylamido-2-methylpropane sulfonic acid (AMPS), effect of high salinity/hardness and temperature seems to be reduced specially for the samples with higher percentage of AMPS co-monomer. The ultimate aim of this work is to develop an understanding of the sulfonated polyacrylamide copolymers with a range of different sulfonation and molecular weight at high salinity and high temperature conditions. Most of the work in this thesis deals with viscosity and adsorption/retention measurements of the sulfonated copolymers and HPAM. The factors which may affect the viscosity of the polymers and have been identified in this work as most likely influencing also adsorption and retention of the polymers are shear rate, polymer concentration, sulfonation degree, molecular weight, NaCl concentration, divalent ion concentration, and temperature. (Author)

Coupling the Alkaline-Surfactant-Polymer Technology and The Gelation Technology to Maximize Oil Production

Energy Technology Data Exchange (ETDEWEB)

Malcolm Pitts; Jie Qi; Dan Wilson; Phil Dowling; David Stewart; Bill Jones

2005-12-01

gel producing the greatest amount. Higher oil recovery could have been due to higher differential pressures across cores. Aluminum citrate-polyacrylamide gels, chromium acetate-polyacrylamide gels, silicate-polymer, and chromium-xanthan gum gels did not alter an alkaline-surfactant-polymer solution's ability to produce incremental oil. Incremental oil was reduced with the resorcinol-formaldehyde gel system. Total waterflood plus chemical flood oil recovery sequence recoveries were generally similar. Performance and produced polymer evaluation of four alkaline-surfactant-polymer projects concluded that only one of the projects could have benefited from combining the alkaline-surfactant-polymer and gelation technologies. Cambridge, the 1993 Daqing, Mellott Ranch, and the Wardlaw alkaline-surfacant-polymer floods were studied. An initial gel treatment followed by an alkaline-surfactant-polymer flood in the Wardlaw field would have been a benefit due to reduction of fracture flow.

Thermosetting Phthalocyanine Polymers

Science.gov (United States)

Fohlen, G.; Parker, J.; Achar, B.

1985-01-01

Group of phthalocyanine polymers resist thermal degradation. Polymers expected semiconducting. Principal applications probably in molded or laminated parts that have to withstand high temperatures. Polymers made from either of two classes of monomer: Bisphthalonitriles with imide linkages or Bisphthalonitriles with ester-imide linkages.

Precise Control over the Rheological Behavior of Associating Stimuli-Responsive Block Copolymer Gels

Directory of Open Access Journals (Sweden)

Jérémy Brassinne

2015-12-01

Full Text Available “Smart” materials have considerably evolved over the last few years for specific applications. They rely on intelligent macromolecules or (supra-molecular motifs to adapt their structure and properties in response to external triggers. Here, a supramolecular stimuli-responsive polymer gel is constructed from heterotelechelic double hydrophilic block copolymers that incorporate thermo-responsive sequences. These macromolecular building units are synthesized via a three-step controlled radical copolymerization and then hierarchically assembled to yield coordination micellar hydrogels. The dynamic mechanical properties of this particular class of materials are studied in shear flow and finely tuned via temperature changes. Notably, rheological experiments show that structurally reinforcing the micellar network nodes leads to precise tuning of the viscoelastic response and yield behavior of the material. Hence, they constitute promising candidates for specific applications, such as mechano-sensors.

21 CFR 888.3560 - Knee joint patellofemorotibial polymer/metal/polymer semi-constrained cemented prosthesis.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint patellofemorotibial polymer/metal... Devices § 888.3560 Knee joint patellofemorotibial polymer/metal/polymer semi-constrained cemented prosthesis. (a) Identification. A knee joint patellofemorotibial polymer/metal/polymer semi-constrained...

Ferritin nanocontainers that self-direct in synthetic polymer systems

Science.gov (United States)

Sengonul, Merih C.

Currently, there are many approaches to introduce functionality into synthetic polymers. Among these, for example, are copolymerization, grafting, and blending methods. However, modifications made by such methods also change the thermodynamics and rheological properties of the polymer system of interest, and each new modification often requires a costly reoptimization of polymer processing. Such a reoptimalization would not be necessary if new functionality could be introduced via a container whose external surface is chemically and physically tuned to interact with the parent polymer. The contents of the container could then be changed without changing other important properties of the parent polymer. In this context this thesis project explores an innovative nanocontainer platform which can be introduced into phase-separating homopolymer blends. Ferritin is a naturally existing nanocontainer that can be used synthetically to package and selectively transport functional moieties to a particular phase that is either in the bulk or on the surface of a homopolymer blend system. The principal focus of this work centers on modifying the surface of wild ferritin to: (1) render modified ferritin soluble in a non-aqueous solvent; and (2) impart it with self-directing properties when exposed to a homopolymer blend surface or incorporated into the bulk of a homopolymer blend. Wild ferritin is water soluble, and this research project successfully modified wild ferritin by grafting either amine-functional poly(ethylene glycol) (PEG) or short-chain alkanes to carbodiimide activated carboxylate groups on ferritin's surface. Such modified ferritin is soluble in dichloromethane (DCM). Modification was confirmed by ion-exchange chromatography, zeta-potential measurements, and electrospray mass spectroscopy. FT-IR was used to quantify the extent of PEGylation of the reaction products through area ratios of the -C-O-C asymmetric stretching vibration of the grafted PEG chains to the

Field-Amplified Sample Injection-Micellar Electrokinetic Chromatography for the Determination of Benzophenones in Food Simulants

Directory of Open Access Journals (Sweden)

Cristina Félez

2015-07-01

Full Text Available A field-amplified sample injection-micellar electrokinetic chromatography (FASI-MEKC method for the determination of 14 benzophenones (BPs in a food simulant used in migration studies of food packaging materials was developed, allowing almost baseline separation in less than 21 min. The use of a 10 mM sodium dodecyl sulfate (SDS solution as sample matrix was mandatory to achieve FASI enhancement of the analyzed BPs. A 21- to 784-fold sensitivity enhancement was achieved with FASI-MEKC, obtaining limits of detection down to 5.1–68.4 µg/L, with acceptable run-to-run precisions (RSD values lower than 22.3% and accuracy (relative errors lower than 21.0%. Method performance was evaluated by quantifying BPs in the food simulant spiked at 500 µg/L (bellow the established specific migration limit for BP (600 µg/L by EU legislation. For a 95% confidence level, no statistical differences were observed between found and spiked concentrations (probability at the confidence level, p value, of 0.55, showing that the proposed FASI-MEKC method is suitable for the analysis of BPs in food packaging migration studies at the levels established by EU legislation.

Capillary sieving electrophoresis and micellar electrokinetic capillary chromatography produce highly correlated separation of tryptic digests

Science.gov (United States)

Dickerson, Jane A.; Dovichi, Norman J.

2011-01-01

We perform two-dimensional capillary electrophoresis on fluorescently labeled proteins and peptides. Capillary sieving electrophoresis was performed in the first dimension and micellar electrokinetic capillary chromatography was performed in the second. A cellular homogenate was labeled with the fluorogenic reagent FQ and separated using the system. This homogenate generated a pair of ridges; the first had essentially constant migration time in the CSE dimension, while the second had essentially constant migration time in the MEKC dimension. In addition a few spots were scattered through the electropherogram. The same homogenate was digested using trypsin, and then labeled and subjected to the two dimensional separation. In this case, the two ridges observed from the original two-dimensional separation disappeared, and were replaced by a set of spots that fell along the diagonal. Those spots were identified using a local-maximum algorithm and each was fit using a two-dimensional Gaussian surface by an unsupervised nonlinear least squares regression algorithm. The migration times of the tryptic digest components were highly correlated (r = 0.862). When the slowest migrating components were eliminated from the analysis, the correlation coefficient improved to r = 0.956. PMID:20564272

Prediction of average droplet size in flowing immiscible polymer blends

Czech Academy of Sciences Publication Activity Database

Fortelný, Ivan; Jůza, Josef

2017-01-01

Roč. 134, č. 35 (2017), s. 1-12, č. článku 45250. ISSN 0021-8995 R&D Projects: GA ČR(CZ) GA14-17921S Institutional support: RVO:61389013 Keywords : coalescence * droplet breakup * phase structure evolution Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 1.860, year: 2016

Photoinduced reversible switching of charge carrier mobility in conjugated polymers

Czech Academy of Sciences Publication Activity Database

Weiter, M.; Navrátil, J.; Vala, M.; Toman, Petr

2009-01-01

Roč. 48, č. 1 (2009), 10401_1-10401_6 ISSN 1286-0042 R&D Projects: GA ČR GA203/06/0285; GA AV ČR KAN401770651 Institutional research plan: CEZ:AV0Z40500505 Keywords : polymers * switch * charge carrier mobility Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.756, year: 2009

New electroluminescent carbazole-containing conjugated polymer: synthesis, photophysics, and electroluminescence

Czech Academy of Sciences Publication Activity Database

Cimrová, Věra; Ulbricht, C.; Dzhabarov, Vagif; Výprachtický, Drahomír; Egbe, D. A. M.

2014-01-01

Roč. 55, č. 24 (2014), s. 6220-6226 ISSN 0032-3861 R&D Projects: GA ČR GAP106/12/0827; GA ČR(CZ) GA13-26542S Institutional support: RVO:61389013 Keywords : carbazole-containing conjugated polymer * synthesis * photophysics and electroluminescence Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.562, year: 2014

Terminology of Polymers Containing Ionizable or Ionic Groups and of Polymers Containing Ions, VII.3

Directory of Open Access Journals (Sweden)

Jarm, V.

2009-10-01

Full Text Available The class of ionic polymers has widespread application in many areas of everyday life, in industrial production, and in the processes of living matter. The properties of ionic polymers depend on the polymer structure, and the nature, content, and location of the ionic groups. To clear differences among various ionic polymers, the IUPAC recommendations present 34 definitionsfor the ionomer, polyacid, polybase, polyampholytic polymer, ion-exchange polymer, polybetaine, polyelectrolyte, intrinsically conducting polymer, solid polymer electrolyte, etc

Assessment of potential increased oil production by polymer-waterflood in northern and southern mid-continent oil fields. Progress report for the quarter ending December 31, 1978

Energy Technology Data Exchange (ETDEWEB)

None

1978-01-01

Six tasks are reported on: geological and engineering study of the DOE-Kewanee polymer-augmented waterflood, review of polymer injection program in this field, evaluation of results of polymer-augmented waterflood in this field, review of geological and engineering characteristics of oil fields now in waterflood as candidates for polymer augmentation, review of fields currently under primary production, and determination of ranges of future increased oil production from the polymer-water process in the project area.

Simple micellar electrokinetic chromatography method for the determination of hydrogen sulfide in hen tissues.

Science.gov (United States)

Kubalczyk, Paweł; Borowczyk, Kamila; Chwatko, Grażyna; Głowacki, Rafał

2015-04-01

A new method for the determination of hydrogen sulfide in hen tissues has been developed and validated. For estimation of hydrogen sulfide content, a sample (0.1 g) of hen tissue was treated according to the procedure consisted of some essential steps: simultaneous homogenization of a tissue and derivatization of hydrogen sulfide to its S-quinolinium derivative with 2-chloro-1-methylquinolinium tetrafluoroborate, separation of so-formed derivative by micellar electrokinetic chromatography with sweeping, and detection and quantitation with the use of UV detector set to measure analytical signals at 375 nm. Effective electrophoretic separation was achieved using fused silica capillary (effective length 41.5 cm, 75 μm id) and 0.05 mol/L, pH 8 phosphate buffer with the addition of 0.04 mol/L SDS and 26% ACN. The lower limit of quantification was 0.12 μmol hydrogen sulfide in 1 g of tissue. The calibration curve prepared in tissue homogenate for hydrogen sulfide showed linearity in the range from 0.15 to 2.0 μmol/g, with the coefficient of correlation 0.9978. The relative standard deviation of the points of the calibration curve varied from 8.3 to 3.2% RSD. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Exploring novel silicon-containing polymers---From preceramic polymers to conducting polymers with nonlinear optical properties

Energy Technology Data Exchange (ETDEWEB)

Pang, Yi.

1991-10-07

Several new types of silicon-containing preceramic polymers, i.e., poly(diorganosilacetylene) and poly(diorganosilvinylene) have been synthesized with molecular weights from 10,000 to 120,000. These polymers could be thermally converted to SiC with a moderate to high char yields. Ready solubility and good processability made these types of polymers attractive in their applications to ceramics. The thermal polymerization of diethynyldiphenyl-silane, which was reported in 1968 to afford poly(diphenylsilyldiacetylene) via dehydrogenation, was reinvestigated. Spectroscopic studies showed that the polymer had a structure of polyacetylene type not diacetylene. Diphenyldiethynylgermane and a series of diorganodiethynylsilances were synthesized. These could be polymerized in the presence of MoCl{sub 5} or WCl{sub 6} to afford a soluble, violet material with Mw as high as 108,000. 100 refs., 56 figs., 16 tabs.

Optical and rheological studies on weak gel-sol transition in aqueous solutions of poly(N-isopropylacrylamide-block-polystyrene

Directory of Open Access Journals (Sweden)

S. Sanjeevi Prasath

2017-07-01

Full Text Available The optical and rheological properties of aqueous solutions of block copolymer composed of low molecular weight poly(N-isopropylacrylamide-b-polystyrene are studied as a function of temperature. From light scattering measurements the block copolymer solution is found to form micelles at very low concentrations and the critical micellar concentration is identified as 0.005 wt%. Apart from the concentration dependence, a unique temperature dependent micelle formation is noted at 34 °C. Further, temperature dependent refractive index measurements shows that the refractive index increases with temperature (beyond the lower critical solution temperature, 31.6 °C of the polymer, and is attributed to the stable rearrangement of the proximal hydrophobic isopropyl-polystyrene chains in the collapsed polymer so as to overcome the steric hindrance effects offered by the hydrophobic chains. In the polymer concentrations investigated for rheological studies, the solution flows, yet manifested solid like behavior with G' > G" with the modulus being frequency dependent and the magnitude of G' two-fold higher than G" implying a weak gel state. Weak gel states are in general noted at high temperatures in most of the polymer systems, contrary to this, in our studies weak gel state is observed at lower temperature. Further, a transition from weak gel to sol state is observed at slightly elevated temperatures. The reason for the existence of weak gel state below the lower critical solution temperature is due to the micellar entanglements of poly(N-isopropylacrylamide-b-polystyrene with one another and whereas above the lower critical solution temperature disentanglement of the micelles makes the system behave like a viscoelastic liquid.

Synthesis of well-defined semitelechelic poly[N-(2-hydroxypropyl)methacrylamide] polymers with functional group at the .alpha.-end of the polymer chain by RAFT polymerization

Czech Academy of Sciences Publication Activity Database

Šubr, Vladimír; Kostka, Libor; Strohalm, Jiří; Etrych, Tomáš; Ulbrich, Karel

2013-01-01

Roč. 46, č. 6 (2013), s. 2100-2108 ISSN 0024-9297 R&D Projects: GA ČR GAP301/12/1254; GA MŠk EE2.3.30.0029 Institutional support: RVO:61389013 Keywords : RAFT polymerization * N-(2-hydroxypropyl)methacrylamide * semitelechelic polymers Subject RIV: CD - Macromolecular Chemistry Impact factor: 5.927, year: 2013

21 CFR 888.3410 - Hip joint metal/polymer or ceramic/polymer semiconstrained resurfacing cemented prosthesis.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint metal/polymer or ceramic/polymer... Devices § 888.3410 Hip joint metal/polymer or ceramic/polymer semiconstrained resurfacing cemented prosthesis. (a) Identification. A hip joint metal/polymer or ceramic/polymer semi-constrained resurfacing...

The Role of IAEA in Coordinating Research and Transferring Technology in Radiation Chemistry and Processing of Polymers

International Nuclear Information System (INIS)

Haji Saeid, M.

2006-01-01

The IAEA has been playing a significant role in fostering developments in radiation technology in general and radiation processing of polymers in particular, among its Member States (MS) and facilitate know-how/technology transfer to developing MS. The former is usually achieved through coordinated research projects (CRP) and thematic technical meetings, while the latter is mainly accomplished through Technical Cooperation (TC) projects. Coordinated research projects encourage research on, and development and practical application of, radiation technology to foster exchange of scientific and technical information. The CRP brings together typically 10 - 15 groups of participants to share and complement core competencies and work on specific areas of development needed to benefit from an emerging radiation technique and its applications. The technical cooperation (TC) programme helps Member States realize their development priorities through the application of appropriate radiation technology. TC builds national capacities through training, expert advice and delivery of equipment. The impact of the IAEA's efforts is visible by the progress noticeable in adoption of radiation technology and/or growth in the range of activities in several MS in different regions. The IAEA has implemented several coordinated research projects (CRP) recently, including one on-going project, in the field of radiation processing of polymeric materials. The CRPs facilitated the acquisition and dissemination of know-how and technology for controlling of degradation effects in radiation processing of polymers, radiation synthesis of stimuli-responsive membranes, hydrogels and absorbents for separation purposes and the use of radiation processing to prepare biomaterials for applications in medicine. A number of technical cooperation projects have been implemented in this field to strengthen the capability of developing Member States and to create awareness in the industries about the technical

Tritium containing polymers having a polymer backbone substantially void of tritium

Science.gov (United States)

Jensen, G.A.; Nelson, D.A.; Molton, P.M.

1992-03-31

A radioluminescent light source comprises a solid mixture of a phosphorescent substance and a tritiated polymer. The solid mixture forms a solid mass having length, width, and thickness dimensions, and is capable of self-support. In one aspect of the invention, the phosphorescent substance comprises solid phosphor particles supported or surrounded within a solid matrix by a tritium containing polymer. The tritium containing polymer comprises a polymer backbone which is essentially void of tritium. 2 figs.

Fundamental radiation effect on polymers energy transfer from radiation to polymer

International Nuclear Information System (INIS)

Seguchi, T.

2007-01-01

Polymer modification as cross-link, chain scission, and graft-polymerization by radiation is initiated by the quantum energy transferred from radiation to polymers. The active species for chemical reactions are produced through ionization or activation of polymer molecules for any radiation source. The energy transfer occurs mainly by ionic interaction between radiation and polymer molecule, and the contribution from the collision interaction is miner. The radiation of electromagnetic wave as X-ray or γ-ray generates the energetic electron which induces ionic interaction with polymer molecule. The energy loss profile along the penetration to polymer material is much different among the radiation sources of EB, γ-ray, and ion beams in the macroscopic mechanism. In this article, the behavior of single event, that is, the event induced by one electron, γ-ray, ion, and neutron is described by the macroscopic mechanism and by the microscopic mechanism. (authors)

High-Temperature Polymer Composites Tested for Hypersonic Rocket Combustor Backup Structure

Science.gov (United States)

Sutter, James K.; Shin, E. Eugene; Thesken, John C.; Fink, Jeffrey E.

2005-01-01

Significant component weight reductions are required to achieve the aggressive thrust-toweight goals for the Rocket Based Combined Cycle (RBCC) third-generation, reusable liquid propellant rocket engine, which is one possible engine for a future single-stage-toorbit vehicle. A collaboration between the NASA Glenn Research Center and Boeing Rocketdyne was formed under the Higher Operating Temperature Propulsion Components (HOTPC) program and, currently, the Ultra-Efficient Engine Technology (UEET) Project to develop carbon-fiber-reinforced high-temperature polymer matrix composites (HTPMCs). This program focused primarily on the combustor backup structure to replace all metallic support components with a much lighter polymer-matrixcomposite- (PMC-) titanium honeycomb sandwich structure.

Advanced polymers in medicine

CERN Document Server

Puoci, Francesco

2014-01-01

The book provides an up-to-date overview of the diverse medical applications of advanced polymers. The book opens by presenting important background information on polymer chemistry and physicochemical characterization of polymers. This serves as essential scientific support for the subsequent chapters, each of which is devoted to the applications of polymers in a particular medical specialty. The coverage is broad, encompassing orthopedics, ophthalmology, tissue engineering, surgery, dentistry, oncology, drug delivery, nephrology, wound dressing and healing, and cardiology. The development of polymers that enhance the biocompatibility of blood-contacting medical devices and the incorporation of polymers within biosensors are also addressed. This book is an excellent guide to the recent advances in polymeric biomaterials and bridges the gap between the research literature and standard textbooks on the applications of polymers in medicine.

Polyaniline: The infrared spectroscopy of conducting polymer nanotubes (IUPAC Technical Report)

Czech Academy of Sciences Publication Activity Database

Trchová, Miroslava; Stejskal, Jaroslav

2011-01-01

Roč. 83, č. 10 (2011), s. 1803-1817 ISSN 0033-4545 R&D Projects: GA MŠk LA09028 Institutional research plan: CEZ:AV0Z40500505 Keywords : aniline oligomers * fourier transform infrared (FTIR) spectroscopy * IUPAC Polymer Division Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.789, year: 2011

Simple kinetic model of ion induced gas emission from polymers

Czech Academy of Sciences Publication Activity Database

Hnatowicz, Vladimír

2004-01-01

Roč. 215, 1/2 (2004), s. 162-168 ISSN 0168-583X R&D Projects: GA ČR GA106/03/0514; GA AV ČR IAA5011301 Institutional research plan: CEZ:AV0Z1048901 Keywords : polymers * ion irradiation * degradation Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 0.997, year: 2004

Formation of long and thin polymer fiber using nondiffracting beam

Czech Academy of Sciences Publication Activity Database

Ježek, Jan; Čižmár, Tomáš; Neděla, Vilém; Zemánek, Pavel

2006-01-01

Roč. 14, č. 19 (2006), s. 8506-8515 ISSN 1094-4087 R&D Projects: GA AV ČR KJB2065404; GA MŠk(CZ) LC06007 Institutional research plan: CEZ:AV0Z20650511 Keywords : fiber design and fabrication * laser beam shaping * polymers Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 4.009, year: 2006

Grafting of functional methacrylate polymer brushes by photoinduced SET-LRP

Czech Academy of Sciences Publication Activity Database

Vorobii, M.; Pop-Georgievski, Ognen; de los Santos Pereira, Andres; Kostina, N. Yu.; Jezorek, R.; Sedláková, Zdeňka; Percec, V.; Rodriguez-Emmenegger, C.

2016-01-01

Roč. 7, č. 45 (2016), s. 6934-6945 ISSN 1759-9954 R&D Projects: GA ČR(CZ) GJ15-09368Y Grant - others:OPPK(XE) CZ.2.16/3.1.00/21545 Program:OPPK Institutional support: RVO:61389013 Keywords : photo-induced polymerization * polymer brushes * spatial control Subject RIV: CD - Macromolecular Chemistry Impact factor: 5.375, year: 2016

A study on the life extension of polymer materials under radiation environment

International Nuclear Information System (INIS)

Park, K. J; Park, S. W.; Jung, K. S.; Cho, S. H.; Seo, H. S.

2001-12-01

The object of this project is to improve the stability and the economics by reducing the radiation-induced oxidation as a factor of degradation of polymer materials used under the radiation environment. In order to attain the objective of this study and to check the effect of diamond-like carbon(DLC) coating on the anti-oxidation reaction, polymer specimens such as ABS, Acryl, Polycarbonate, Polyethylene, Polypropylene, PVC coating DLC thin layer were exposed to high-level gamma radiation, and their irradiation effects were investigated. A plasma-enhanced chemical vapor deposition method was adopted in fabricating a DLC thin film on the polymer specimens, which were irradiated with the non-DLC film deposited specimens under the gamma radiation emitted from Co-60 source from 1x10 5 to 1x10 8 rads exposure. According to the characterization of irradiated specimens from the elapsed time of minimum 4 hours to a maximum of 105 days after the irradiation, the DLC deposition on the polymer surface was revealed to contribute to the improvement on the resistance of the radiation-induced oxidation in this study

Investigating accidents involving aircraft manufactured from polymer composite materials

Science.gov (United States)

Dunn, Leigh

This study looks into the examination of polymer composite wreckage from the perspective of the aircraft accident investigator. It develops an understanding of the process of wreckage examination as well as identifying the potential for visual and macroscopic interpretation of polymer composite aircraft wreckage. The in-field examination of aircraft wreckage, and subsequent interpretations of material failures, can be a significant part of an aircraft accident investigation. As the use of composite materials in aircraft construction increases, the understanding of how macroscopic failure characteristics of composite materials may aid the field investigator is becoming of increasing importance.. The first phase of this research project was to explore how investigation practitioners conduct wreckage examinations. Four accident investigation case studies were examined. The analysis of the case studies provided a framework of the wreckage examination process. Subsequently, a literature survey was conducted to establish the current level of knowledge on the visual and macroscopic interpretation of polymer composite failures. Relevant literature was identified and a compendium of visual and macroscopic characteristics was created. Two full-scale polymer composite wing structures were loaded statically, in an upward bending direction, until each wing structure fractured and separated. The wing structures were subsequently examined for the existence of failure characteristics. The examination revealed that whilst characteristics were present, the fragmentation of the structure destroyed valuable evidence. A hypothetical accident scenario utilising the fractured wing structures was developed, which UK government accident investigators subsequently investigated. This provided refinement to the investigative framework and suggested further guidance on the interpretation of polymer composite failures by accident investigators..

Biomass Biorefinery for the production of Polymers and Fuels

Energy Technology Data Exchange (ETDEWEB)

Dr. Oliver P. Peoples

2008-05-05

The conversion of biomass crops to fuel is receiving considerable attention as a means to reduce our dependence on foreign oil imports and to meet future energy needs. Besides their use for fuel, biomass crops are an attractive vehicle for producing value added products such as biopolymers. Metabolix, Inc. of Cambridge proposes to develop methods for producing biodegradable polymers polyhydroxyalkanoates (PHAs) in green tissue plants as well as utilizating residual plant biomass after polymer extraction for fuel generation to offset the energy required for polymer extraction. The primary plant target is switchgrass, and backup targets are alfalfa and tobacco. The combined polymer and fuel production from the transgenic biomass crops establishes a biorefinery that has the potential to reduce the nation’s dependence on foreign oil imports for both the feedstocks and energy needed for plastic production. Concerns about the widespread use of transgenic crops and the grower’s ability to prevent the contamination of the surrounding environment with foreign genes will be addressed by incorporating and expanding on some of the latest plant biotechnology developed by the project partners of this proposal. This proposal also addresses extraction of PHAs from biomass, modification of PHAs so that they have suitable properties for large volume polymer applications, processing of the PHAs using conversion processes now practiced at large scale (e.g., to film, fiber, and molded parts), conversion of PHA polymers to chemical building blocks, and demonstration of the usefulness of PHAs in large volume applications. The biodegradability of PHAs can also help to reduce solid waste in our landfills. If successful, this program will reduce U.S. dependence on imported oil, as well as contribute jobs and revenue to the agricultural economy and reduce the overall emissions of carbon to the atmosphere.

Applications of functionalized polymers in catalysis. Progress report 3, July 15, 1979-July 1, 1980

Energy Technology Data Exchange (ETDEWEB)

Bergbreiter, D.E.

1980-07-01

Research on applications of polymers in catalysis has encompassed three areas: the use of functionalized polymers to detect soluble intermediates in heterogeneous Group VIII metal catalyzed arene hydrogenations; a study of olefin isomerization and hydrogenations catalyzed by polystyrene supported bis(cyclopentadienyl)titanium dichloride and an alkylmagnesium halide; and the acceleration in rate of an olefin hydrogenation catalyzed by homogeneous rhodium and ruthenium complexes as a result of absorption of triphenylphosphine by silver (I) polystyrenesulfonate. The first project found that polymer bound trapping agents were unable to detect soluble intermediates such as dienes, free radicals, or reducing agents in platinum-catalyzed benzene hydrogenation at 60 psi H/sub 2/ and 30/sup 0/C. The inability to detect diene intermediates was shown to be the result of the lower reactivity of the polymeric reagent versus an active catalyst. The polymer-supported titanium catalysts studied were unusual in that immobilization of a catalyst in this case altered the catalyst's specificity relative to its homogeneous counterpart. Preliminary results from the third project demonstrate the potential of simple functionalized polymers to improve existing homogeneously catalyzed reactions. Rate increases for olefin hydrogenations using C1Rh(Ph/sub 3/P)/sub 3/, HRh(CO)(Ph/sub 3/)/sub 3/, HRu(OAc)(Ph/sub 3/P), H/sub 2/Ru(Ph/sub 3/P)/sub 4/, Cl/sub 2/Ru(Ph/sub 3/P)/sub 3/, and Cl/sub 2/Ru(Ph/sub 3/P)/sub 4/ ranged from 25 to 3000%.

Nature's Mechanisms for Tough, Self-healing Polymers and Polymer Adhesives

Science.gov (United States)

Hansma, Paul

2007-03-01

Spider silk^2 and the natural polymer adhesives in abalone shells^3 and bone^4,5 can give us insights into nature's mechanisms for tough, self-healing polymers and polymer adhesives. The natural polymer adhesives in biomaterials have been optimized by evolution. An optimized polymer adhesive has five characteristics. 1) It holds together the strong elements of the composite. 2) It yields just before the strong elements would otherwise break. 3) It dissipates large amounts of energy as it yields. 4) It self heals after it yields. 5) It takes just a few percent by weight. Both natural polymer adhesives and silk rely on sacrificial bonds and hidden length for toughness and self-healing.^6 A relatively large energy, of order 100eV, is required to stretch a polymer molecule after a weak bond, a sacrificial bond, breaks and liberates hidden length, which was previously hidden, typically in a loop or folded domain, from whatever was stretching the polymer. The bond is called sacrificial if it breaks at forces well below the forces that could otherwise break the polymer backbone, typically greater than 1nN. In many biological cases, the breaking of sacrificial bonds has been found to be reversible, thereby also providing a ``self-healing'' property to the material.^2-4 Individual polymer adhesive molecules based on sacrificial bonds and hidden length can supply forces of order 300pN over distances of 100s of nanometers. Model calculations show that a few percent by weight of adhesives based on these principles could be optimized adhesives for high performance composite materials including nanotube and graphene sheet composites. ^2N. Becker, E. Oroudjev, S. Mutz et al., Nature Materials 2 (4), 278 (2003). ^3B. L. Smith, T. E. Schaffer, M. Viani et al., Nature 399 (6738), 761 (1999). ^4J. B. Thompson, J. H. Kindt, B. Drake et al., Nature 414 (6865), 773 (2001). ^5G. E. Fantner, T. Hassenkam, J. H. Kindt et al., Nature Materials 4, 612 (2005). ^6G. E. Fantner, E. Oroudjev, G

Photoinitiated grafting of porous polymer monoliths and thermoplastic polymers for microfluidic devices

Science.gov (United States)

Frechet, Jean M. J. [Oakland, CA; Svec, Frantisek [Alameda, CA; Rohr, Thomas [Leiden, NL

2008-10-07

A microfluidic device preferably made of a thermoplastic polymer that includes a channel or a multiplicity of channels whose surfaces are modified by photografting. The device further includes a porous polymer monolith prepared via UV initiated polymerization within the channel, and functionalization of the pore surface of the monolith using photografting. Processes for making such surface modifications of thermoplastic polymers and porous polymer monoliths are set forth.

Influence of non-thermal plasma on structural and electrical properties of globular and nanostructured conductive polymer polypyrrole in water suspension

Czech Academy of Sciences Publication Activity Database

Galář, P.; Khun, J.; Kopecký, D.; Scholtz, V.; Trchová, Miroslava; Fučíková, A.; Jirešová, J.; Fišer, L.

2017-01-01

Roč. 7, 08 November (2017), s. 1-10, č. článku 15068. ISSN 2045-2322 R&D Projects: GA ČR(CZ) GA17-04109S Institutional support: RVO:61389013 Keywords : conductive polymer * polypyrrole * plasma Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 4.259, year: 2016

Performance limitations of polymer electrolytes based on ethylene oxide polymers

International Nuclear Information System (INIS)

Buriez, Olivier; Han, Yong Bong; Hou, Jun; Kerr, John B.; Qiao, Jun; Sloop, Steven E.; Tian, Minmin; Wang, Shanger

1999-01-01

Studies of polymer electrolyte solutions for lithium-polymer batteries are described. Two different salts, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and lithium trifluoromethanesulfonate (LiTf), were dissolved in a variety of polymers. The structures were all based upon the ethylene oxide unit for lithium ion solvation and both linear and comb-branch polymer architectures have been examined. Conductivity, salt diffusion coefficient and transference number measurements demonstrate the superior transport properties of the LiTFSI salt over LiTf. Data obtained on all of these polymers combined with LiTFSI salts suggest that there is a limit to the conductivity achievable at room temperature, at least for hosts containing ethylene oxide units. The apparent conductivity limit is 5 x 10-5 S/cm at 25 C. Providing that the polymer chain segment containing the ethylene oxide units is at least 5-6 units long there appears to be little influence of the polymer framework to which the solvating groups are attached. To provide adequate separator function, the mechanical properties may be disconnected from the transport properties by selection of an appropriate architecture combined with an adequately long ethylene oxide chain. For both bulk and interfacial transport of the lithium ions, conductivity data alone is insufficient to understand the processes that occur. Lithium ion transference numbers and salt diffusion coefficients also play a major role in the observed behavior and the transport properties of these polymer electrolyte solutions appear to be quite inadequate for ambient temperature performance. At present, this restricts the use of such systems to high temperature applications. Several suggestions are given to overcome these obstacles

BEAM applications to polymer materials

International Nuclear Information System (INIS)

Tagawa, Seiichi

1994-01-01

Recently papers about beam applications to polymers have been increasing rapidly both in the fundamental and applied fields. Fairly large number of papers have been published in the fundamental aspects of radiation effects of beam applications to polymers such as pulse radiolysis and high density electronic excitation effects. A number of papers have been published in the more applied aspects of beam applications to polymers such as radiation processing and curing. The present paper describes recent beam applications to polymers. 1. Radiation Effects on Polymers; Radiation effects on polymers have been studied for more than 40 years. Most of work on radiation effects on polymers has been carried out by using high energy photon (gamma-ray) and electron beams, since polymers are sensitive to any kinds of ionizing radiation. Even non-ionizing radiation such as ultraviolet and visible light excites electronic excited states of polymers and then photo-chemical reactions of polymers are induced from the electronic excited states. Studies on radiation effects of other ionizing radiation on polymers have not been so popular for a long time. Recently application of new radiation such as ion beams to polymers have been worthy of remark in fields of advanced science and technology, since new radiation beams induce different radiation effects from those induced by high energy gamma-rays and electrons. 2. Beam Applications of Polymers; Recent progress in beam applications to polymers such as radiation processing and curing, x-ray and electron beam microlithography, and applications of new beams such as ion beams to polymers has been reviewed. (author)

Polymer brushes based on PLLA-b-PEO colloids for the preparation of protein resistant PLA surfaces

Czech Academy of Sciences Publication Activity Database

Mázl Chánová, Eliška; Pop-Georgievski, Ognen; Kumorek, Marta M.; Janoušková, Olga; Machová, Luďka; Kubies, Dana; Rypáček, František

2017-01-01

Roč. 5, č. 6 (2017), s. 1130-1143 ISSN 2047-4830 R&D Projects: GA ČR(CZ) GJ15-09368Y; GA MZd(CZ) NV16-28254A; GA MŠk(CZ) LQ1604; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61389013 Keywords : polymer brush * poly(ethylene oxide) * polylactide Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 4.210, year: 2016

Recycling of polymers: a review.

Science.gov (United States)

Ignatyev, Igor A; Thielemans, Wim; Vander Beke, Bob

2014-06-01

Plastics are inexpensive, easy to mold, and lightweight. These and many other advantages make them very promising candidates for commercial applications. In many areas, they have substantially suppressed traditional materials. However, the problem of recycling still is a major challenge. There are both technological and economic issues that restrain the progress in this field. Herein, a state-of-art overview of recycling is provided together with an outlook for the future by using popular polymers such as polyolefins, poly(vinyl chloride), polyurethane, and poly(ethylene terephthalate) as examples. Different types of recycling, primary, secondary, tertiary, quaternary, and biological recycling, are discussed together with related issues, such as compatibilization and cross-linking. There are various projects in the European Union on research and application of these recycling approaches; selected examples are provided in this article. Their progress is mirrored by granted patents, most of which have a very limited scope and narrowly cover certain technologies. Global introduction of waste utilization techniques to the polymer market is currently not fully developed, but has an enormous potential. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Polymer light emitting diodes

International Nuclear Information System (INIS)

Gautier-Thianche, Emmmanuelle

1998-01-01

We study sandwich type semiconducting polymer light emitting diodes; anode/polymer/cathode. ITO is selected as anode, this polymer is a blend of a commercially available polymer with a high hole transport ability: polyvinyl-carbazole and a laser dye: coumarin-515. Magnesium covered with silver is chosen for the anode. We study the influence of polymer thickness and coumarin doping ratio on electroluminescence spectrum, electric characteristics and quantum efficiency. An important drawback is that diodes lifetime remains low. In the second part of our study we determine degradations causes with X-Ray reflectivity experiments. It may be due to ITO very high roughness. We realize a new type of planar electroluminescent device: a channel type electroluminescent device in which polymer layer is inserted into an aluminium channel. Such a device is by far more stable than using classical sandwich structures with the same polymer composition: indeed, charges are generated by internal-field ionization and there is no injection from the electrode to the polymer. This avoids electrochemical reactions at electrodes, thus reducing degradations routes. (author) [fr

Polymers for Combating Biocorrosion

Directory of Open Access Journals (Sweden)

Jing Guo

2018-03-01

Full Text Available Biocorrosion has been considered as big trouble in many industries and marine environments due to causing of great economic loss. The main disadvantages of present approaches to prevent corrosion include being limited by environmental factors, being expensive, inapplicable to field, and sometimes inefficient. Studies show that polymer coatings with anticorrosion and antimicrobial properties have been widely accepted as a novel and effective approach to prevent biocorrosion. The main purpose of this review is to summarize up the progressive status of polymer coatings used for combating microbial corrosion. Polymers used to synthesize protective coatings are generally divided into three categories: (i traditional polymers incorporated with biocides, (ii antibacterial polymers containing quaternary ammonium compounds, and (iii conductive polymers. The strategies to synthesize polymer coatings resort mainly to grafting antibacterial polymers from the metal substrate surface using novel surface-functionalization approaches, such as free radical polymerization, chemically oxidative polymerization, and surface-initiated atom transfer radical polymerization, as opposed to the traditional approaches of dip coating or spin coating.

Self-cleaning skin-like prosthetic polymer surfaces

Science.gov (United States)

Simpson, John T [Clinton, TN; Ivanov, Ilia N [Knoxville, TN; Shibata, Jason [Manhattan Beach, CA

2012-03-27

An external covering and method of making an external covering for hiding the internal endoskeleton of a mechanical (e.g., prosthetic) device that exhibits skin-like qualities is provided. The external covering generally comprises an internal bulk layer in contact with the endoskeleton of the prosthetic device and an external skin layer disposed about the internal bulk layer. The external skin layer is comprised of a polymer composite with carbon nanotubes embedded therein. The outer surface of the skin layer has multiple cone-shaped projections that provide the external skin layer with superhydrophobicity. The carbon nanotubes are preferably vertically aligned between the inner surface and outer surface of the external skin layer in order to provide the skin layer with the ability to transmit heat. Superhydrophobic powders may optionally be used as part of the polymer composite or applied as a coating to the surface of the skin layer to enhance superhydrophobicity.

Inhibitor-decorated Polymer Conjugates Targeting Fibroblast Activation Protein

Czech Academy of Sciences Publication Activity Database

Dvořáková, Petra; Bušek, P.; Knedlík, Tomáš; Schimer, Jiří; Etrych, Tomáš; Kostka, Libor; Stollinová Šromová, L.; Šubr, Vladimír; Šácha, Pavel; Šedo, A.; Konvalinka, Jan

2017-01-01

Roč. 60, č. 20 (2017), s. 8385-8393 ISSN 0022-2623 R&D Projects: GA MZd(CZ) NV15-31379A; GA MŠk(CZ) LM2015064; GA MŠk LO1302 Institutional support: RVO:61388963 ; RVO:61389013 Keywords : dipeptidyl peptidase IV * metastatic colorectal cancer * integral membrane protease Subject RIV: CE - Biochemistry; CD - Macromolecular Chemistry (UMCH-V) OBOR OECD: Biochemistry and molecular biology; Polymer science (UMCH-V) Impact factor: 6.259, year: 2016

Synthesis and Evaluation of Tetramethylguanidinium-Polyethylenimine Polymers as Efficient Gene Delivery Vectors

Directory of Open Access Journals (Sweden)

Manohar Mahato

2014-01-01

Full Text Available Previously, we demonstrated that 6-(N,N,N′,N′-tetramethylguanidinium chloride-hexanoyl-polyethylenimine (THP polymers exhibited significantly enhanced transfection efficiency and cell viability. Here, in the present study, we have synthesized a series of N,N,N′,N′-tetramethylguanidinium-polyethylenimine (TP1-TP5 polymers via a single-step reaction involving peripheral primary amines of bPEI and varying amounts of 2-(1H-benzotriazol-1-yl-1,1,3,3-tetramethyluronium hexafluorophosphate (HBTU. These polymers were found to interact efficiently with negatively charged pDNA and formed stable complexes in the size range of ~240–450 nm. Acid-base titration profiles revealed improved buffering capacity of TP polymers as compared to bPEI. Transfection and cytotoxicity assays performed with TP/pDNA complexes on HEK293, CHO, and HeLa cells showed significantly higher transfection efficiency and cell viability with one of the complexes, TP2/pDNA complex, exhibited the highest transfection efficiency (~1.4–2.3-fold outcompeting native bPEI and the commercially available transfection reagent, Lipofectamine 2000. Compared to previously reported THP polymers, the transfection efficiency of TP/pDNA complexes was found to be lower, as examined by flow cytometry. These results highlight the importance of the hydrophobic C-6 linker in THP polymers in forming compact nanostructures with pDNA, which might lead to efficient uptake and internalization of the complexes; however, the projected TP polymers offer an advantage of their rapid and economical one-step synthesis.

Photoelectrochemical Polymerization of EDOT for Solid State Dye Sensitized Solar Cells: Role of Dye and Solvent

International Nuclear Information System (INIS)

Zhang, Jinbao; Jarboui, Adel; Vlachopoulos, Nick; Jouini, Mohamed; Boschloo, Gerrit

2015-01-01

The aromatic-unit, commercially available, and cost-effective precursor 3, 4-ethylenedioxythiophene (EDOT), was employed instead of bis-EDOT to generate by in-situ photoelectrochemical polymerization (PEP) a conducting polymer-type hole conductor poly (3, 4-ethylenedioxythiophene) (PEDOT) for dye sensitized solar cell (DSC) devices. In order to conduct efficiently the PEP of EDOT, two electrolytic media, aqueous micellar and organic, and two Donor-π-Acceptor sensitizers, were investigated. By using the electrolytic aqueous micellar medium, the PEP was efficient due to the low oxidation potential of the precursor in water. A DSC device based on PEDOT generated from aqueous PEP showed an energy conversion efficiency (η) of 3.0% under 100 mWcm"−"2, higher by two orders of magnitude than that of a DSC device based on PEDOT from organic PEP (η = 0.04%). The comparison of the properties of the as-obtained PEDOT polymers from aqueous and organic PEP by UV–VIS–NIR measurements shows the formation of PEDOT at a highly doped state from aqueous PEP. The thermodynamic and kinetic requirements for efficiency of PEP process in each medium are investigated and discussed on the basis of the light absorption abilities and electrochemical redox potentials measured for the two organic sensitizers.

Rapid Polymer Sequencer

Science.gov (United States)

Stolc, Viktor (Inventor); Brock, Matthew W (Inventor)

2013-01-01

Method and system for rapid and accurate determination of each of a sequence of unknown polymer components, such as nucleic acid components. A self-assembling monolayer of a selected substance is optionally provided on an interior surface of a pipette tip, and the interior surface is immersed in a selected liquid. A selected electrical field is impressed in a longitudinal direction, or in a transverse direction, in the tip region, a polymer sequence is passed through the tip region, and a change in an electrical current signal is measured as each polymer component passes through the tip region. Each of the measured changes in electrical current signals is compared with a database of reference electrical change signals, with each reference signal corresponding to an identified polymer component, to identify the unknown polymer component with a reference polymer component. The nanopore preferably has a pore inner diameter of no more than about 40 nm and is prepared by heating and pulling a very small section of a glass tubing.

PHOTOREFRACTIVE POLYMERS

NARCIS (Netherlands)

Morichere, D; Malliaras, G.G; Krasnikov, V.V.; Bolink, H.J; Hadziioannou, G

The use of polymers as photorefractive materials offers many advantages : flexibility in synthesis, doping, processing and low cost. The required functionalities responsible for photorefractivity, namely charge generation, transport, trapping and linear electrooptic effect are given in the polymer

Photorefractive polymers

NARCIS (Netherlands)

Bolink, Hendrik Jan; Hadziioannou, G

1997-01-01

This thesis describes the synthesis and properties of photorefractive polymers. Photorefractive polymers are materials in which the refractive index can be varied by the interaction with light. Unlike in numerous other photosensitive materials, in photorefractive materials this occurs via