HPMA copolymer conjugates with reduced anti-CD20 antibody for cell-specific drug targeting. I. Synthesis and in vitro evaluation of binding efficacy and cytostatic activity

Czech Academy of Sciences Publication Activity Database

Etrych, Tomáš; Strohalm, Jiří; Kovář, Lubomír; Kabešová, Martina; Říhová, Blanka; Ulbrich, Karel

2009-01-01

Roč. 140, č. 1 (2009), s. 18-26 ISSN 0168-3659 R&D Projects: GA MŠk 1M0505; GA AV ČR IAAX00500803 Institutional research plan: CEZ:AV0Z40500505; CEZ:AV0Z50200510 Keywords : HPMA copolymers * drug delivery systems * doxorubicin * monoclonal anti-CD20 antibody * drug targeting Subject RIV: CD - Macromolecular Chemistry Impact factor: 5.949, year: 2009

Amphiphilic HPMA-LMA copolymers increase the transport of Rhodamine 123 across a BBB model without harming its barrier integrity.

Science.gov (United States)

Hemmelmann, Mirjam; Metz, Verena V; Koynov, Kaloian; Blank, Kerstin; Postina, Rolf; Zentel, Rudolf

2012-10-28

The successful non-invasive treatment of diseases associated with the central nervous system (CNS) is generally limited by poor brain permeability of various developed drugs. The blood-brain barrier (BBB) prevents the passage of therapeutics to their site of action. Polymeric drug delivery systems are promising solutions to effectively transport drugs into the brain. We recently showed that amphiphilic random copolymers based on the hydrophilic p(N-(2-hydroxypropyl)-methacrylamide), pHPMA, possessing randomly distributed hydrophobic p(laurylmethacrylate), pLMA, are able to mediate delivery of domperidone into the brain of mice in vivo. To gain further insight into structure-property relations, a library of carefully designed polymers based on p(HPMA) and p(LMA) was synthesized and tested applying an in vitro BBB model which consisted of human brain microvascular endothelial cells (HBMEC). Our model drug Rhodamine 123 (Rh123) exhibits, like domperidone, a low brain permeability since both substances are recognized by efflux transporters at the BBB. Transport studies investigating the impact of the polymer architecture in relation to the content of hydrophobic LMA revealed that random p(HPMA)-co-p(LMA) having 10mol% LMA is the most auspicious system. The copolymer significantly increased the permeability of Rh123 across the HBMEC monolayer whereas transcytosis of the polymer was very low. Further investigations on the mechanism of transport showed that integrity and barrier function of the BBB model were not harmed by the polymer. According to our results, p(HPMA)-co-p(LMA) copolymers are a promising delivery system for neurological therapeutics and their application might open alternative treatment strategies. Copyright © 2012 Elsevier B.V. All rights reserved.

Conjugated and Entrapped HPMA-PLA Nano-Polymeric Micelles Based Dual Delivery of First Line Anti TB Drugs: Improved and Safe Drug Delivery against Sensitive and Resistant Mycobacterium Tuberculosis.

Science.gov (United States)

Upadhyay, Seema; Khan, Iliyas; Gothwal, Avinash; Pachouri, Praveen K; Bhaskar, N; Gupta, Umesh D; Chauhan, Devendra S; Gupta, Umesh

2017-09-01

First line antiTB drugs have several physical and toxic manifestations which limit their applications. RIF is a hydrophobic drug and has low water solubility and INH is hepatotoxic. The main objective of the study was to synthesize, characterize HPMA-PLA co-polymeric micelles for the effective dual delivery of INH and RIF. HPMA-PLA co-polymer and HPMA-PLA-INH (HPI) conjugates were synthesized and characterized by FT-IR and 1 H-NMR spectroscopy. Later on RIF loaded HPMA-PLA-INH co-polymeric micelles (PMRI) were formulated and characterized for size, zeta potential and surface morphology (SEM, TEM) as well as critical micellar concentration. The safety was assessed through RBC's interaction study. The prepared PMRI were evaluated through MABA assay against sensitive and resistant strains of M. Tuberculosis. Size, zeta and entrapment efficiency for RIF loaded HPMA-PLA-INH polymeric micelles (PMRI) was 87.64 ± 1.98 nm, -19 ± 1.93 mV and 97.2 ± 1.56%, respectively. In vitro release followed controlled and sustained delivery pattern. Sustained release was also supported by release kinetics. Haemolytic toxicity of HPI and PMRI was 8.57 and 7.05% (p PLA polymeric micelles (PMRI) were more effective against sensitive and resistant M tuberculosis. The developed approach can lead to improved patient compliance and reduced dosing in future, offering improved treatment of tuberculosis.

Traceless bioresponsive shielding of adenovirus hexon with HPMA copolymers maintains transduction capacity in vitro and in vivo

Czech Academy of Sciences Publication Activity Database

Prill, J.-M.; Šubr, Vladimír; Pasquarelli, N.; Engler, T.; Hoffmeister, A.; Kochanek, S.; Ulbrich, Karel; Kreppel, F.

2014-01-01

Roč. 9, č. 1 (2014), e82716_1-e82716_15 E-ISSN 1932-6203 Grant - others:AV ČR(CZ) AP0802 Program:Akademická prémie - Praemium Academiae Institutional support: RVO:61389013 Keywords : adenovirus * HPMA copolymers * bioresponsive shielding Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.234, year: 2014

Synthesis and Properties of Star HPMA Copolymer Nanocarriers Synthesised by RAFT Polymerisation Designed for Selective Anticancer Drug Delivery and Imaging.

Science.gov (United States)

Chytil, Petr; Koziolová, Eva; Janoušková, Olga; Kostka, Libor; Ulbrich, Karel; Etrych, Tomáš

2015-06-01

High-molecular-weight star polymer drug nanocarriers intended for the treatment and/or visualisation of solid tumours were synthesised, and their physico-chemical and preliminary in vitro biological properties were determined. The water-soluble star polymer carriers were prepared by the grafting of poly(amido amine) (PAMAM) dendrimers by hetero-telechelic N-(2-hydroxypropyl)methacrylamide (HPMA) copolymers, synthesised by the controlled radical Reversible Addition Fragmentation chain Transfer (RAFT) polymerisation. The well-defined star copolymers with Mw values ranging from 2 · 10(5) to 6 · 10(5) showing a low dispersity (approximately 1.2) were prepared in a high yield. A model anticancer drug, doxorubicin, was bound to the star polymer through a hydrazone bond, enabling the pH-controlled drug release in the target tumour tissue. The activated polymer arm ends of the star copolymer carrier enable a one-point attachment for the targeting ligands and/or a labelling moiety. In this study, the model TAMRA fluorescent dye was used to prove the feasibility of the polymer carrier visualisation by optical imaging in vitro. The tailor-made structure of the star polymer carriers should facilitate the synthesis of targeted polymer-drug conjugates, even polymer theranostics, for simultaneous tumour drug delivery and imaging. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

177Lu-labeled HPMA copolymers utilizing cathepsin B and S cleavable linkers: Synthesis, characterization and preliminary in vivo investigation in a pancreatic cancer model

International Nuclear Information System (INIS)

Ogbomo, Sunny M.; Shi, Wen; Wagh, Nilesh K.; Zhou, Zhengyuan; Brusnahan, Susan K.; Garrison, Jered C.

2013-01-01

Introduction: A major barrier to the advancement of therapeutic nanomedicines has been the non-target toxicity caused by the accumulation of the drug delivery systems in organs associated with the reticuloendothelial system, particularly the liver and spleen. Herein, we report the development of peptide based metabolically active linkers (MALs) that are enzymatically cleaved by cysteine cathepsin B and S, two proteases highly expressed in the liver and spleen. The overall goal of this approach is to utilize the MALs to lower the non-target retention and toxicity of radiolabeled drug delivery systems, thus resulting in higher diagnostic and radiotherapeutic efficacy. Methods: In this study three MALs (MAL0, MAL1 and MAL2) were investigated. MAL1 and MAL2 are composed of known substrates of cathepsin B and S, respectively, while MAL0 is a non-cleavable control. Both MAL1 and MAL2 were shown to undergo enzymatic cleavage with the appropriate cathepsin protease. Subsequent to conjugation to the HPMA copolymer and radiolabeling with 177 Lu, the peptide–polymer conjugates were renamed 177 Lu-metabolically active copolymers ( 177 Lu-MACs) with the corresponding designations: 177 Lu-MAC0, 177 Lu-MAC1 and 177 Lu-MAC2. Results: In vivo evaluation of the 177 Lu-MACs was performed in an HPAC human pancreatic cancer xenograft mouse model. 177 Lu-MAC1 and 177 Lu-MAC2 demonstrated 3.1 and 2.1 fold lower liver retention, respectively, compared to control ( 177 Lu-MAC0) at 72 h post-injection. With regard to spleen retention, 177 Lu-MAC1 and 177 Lu-MAC2 each exhibited a nearly fourfold lower retention, relative to control, at the 72 h time point. However, the tumor accumulation of the 177 Lu-MAC0 was two to three times greater than 177 Lu-MAC1 and 177 Lu-MAC2 at the same time point. The MAL approach demonstrated the capability of substantially reducing the non-target retention of the 177 Lu-labeled HPMA copolymers. Conclusions: While further studies are needed to optimize the

In Vitro and In Vivo Effect of HPMA Copolymer-bound Doxorubicin Targeted to Transferrin Receptor of B-cell Lymphoma 38C13

Czech Academy of Sciences Publication Activity Database

Kovář, Marek; Strohalm, Jiří; Ulbrich, Karel; Říhová, Blanka

2002-01-01

Roč. 10, č. 1 (2002), s. 23-30 ISSN 1061-186X Institutional research plan: CEZ:AV0Z5020903 Keywords : targeting * transferrin * hpma copolymer Subject RIV: EC - Immunology Impact factor: 2.045, year: 2002

Detection and cellular localisation of the synthetic soluble macromolecular drug carrier pHPMA

Energy Technology Data Exchange (ETDEWEB)

Kissel, Maria; Peschke, Peter; Strunz, Anke M.; Kuehnlein, Rainer; Debus, Juergen [Department of Radiation Oncology, E0505, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Subr, Vladimir; Ulbrich, Karel [Institute of Macromolecular Chemistry, Prague (Czech Republic); Friedrich, Eckhard [Division of Biology, University of Koblenz-Landau, Landau (Germany)

2002-08-01

Synthetic macromolecules such as copolymers of N-(2-hydroxypropyl)methacrylamide (pHPMA) are potential carriers for the delivery of drugs owing to their ability to passively accumulate in solid tumours [enhanced permeation and retention (EPR) effect]. To gain further knowledge about the biodistribution and the cellular localisation, poly(HPMA) was prepared for labelling by introducing biotin molecules. Biotinylated pHPMA (5 mol%) was intravenously injected into tumour-bearing rats and the accumulation of biotin-pHPMA was visualised using a streptavidin-alkaline phosphatase technique at day 7 post injection. In spite of the high solubility of pHPMA copolymers and the lack of attachment to cell structures, the biotinylated polymer could be easily detected in tissues fixed in 10% paraformaldehyde-phosphate buffer at 4 C for 48 h. While biotin-pHPMA could be detected intracytoplasmically in liver and spleen, a predominantly interstitial localisation was observed within the anaplastic prostate carcinoma (Dunning R3327-AT1). How biotin as a label influences the biodistribution of poly(HPMA) was assessed by scintigraphy, autoradiography and histology comparing homopolymer poly(HPMA) with biotin-pHPMA. The organ distribution patterns of the two polymers correlated well, except with respect to kidney. It is assumed that the accumulation of biotin-pHPMA in the distal tubuli is due to a biotin transporter in the brush border membrane. The technique presented is useful for a more comprehensive understanding of the biodistribution of soluble macromolecules. (orig.)

Detection and cellular localisation of the synthetic soluble macromolecular drug carrier pHPMA

International Nuclear Information System (INIS)

Kissel, Maria; Peschke, Peter; Strunz, Anke M.; Kuehnlein, Rainer; Debus, Juergen; Subr, Vladimir; Ulbrich, Karel; Friedrich, Eckhard

2002-01-01

Synthetic macromolecules such as copolymers of N-(2-hydroxypropyl)methacrylamide (pHPMA) are potential carriers for the delivery of drugs owing to their ability to passively accumulate in solid tumours [enhanced permeation and retention (EPR) effect]. To gain further knowledge about the biodistribution and the cellular localisation, poly(HPMA) was prepared for labelling by introducing biotin molecules. Biotinylated pHPMA (5 mol%) was intravenously injected into tumour-bearing rats and the accumulation of biotin-pHPMA was visualised using a streptavidin-alkaline phosphatase technique at day 7 post injection. In spite of the high solubility of pHPMA copolymers and the lack of attachment to cell structures, the biotinylated polymer could be easily detected in tissues fixed in 10% paraformaldehyde-phosphate buffer at 4 C for 48 h. While biotin-pHPMA could be detected intracytoplasmically in liver and spleen, a predominantly interstitial localisation was observed within the anaplastic prostate carcinoma (Dunning R3327-AT1). How biotin as a label influences the biodistribution of poly(HPMA) was assessed by scintigraphy, autoradiography and histology comparing homopolymer poly(HPMA) with biotin-pHPMA. The organ distribution patterns of the two polymers correlated well, except with respect to kidney. It is assumed that the accumulation of biotin-pHPMA in the distal tubuli is due to a biotin transporter in the brush border membrane. The technique presented is useful for a more comprehensive understanding of the biodistribution of soluble macromolecules. (orig.)

HPMA-based polymeric micelles for curcumin solubilization and inhibition of cancer cell growth.

Science.gov (United States)

Naksuriya, Ornchuma; Shi, Yang; van Nostrum, Cornelus F; Anuchapreeda, Songyot; Hennink, Wim E; Okonogi, Siriporn

2015-08-01

Curcumin (CM) has been reported as a potential anticancer agent. However, its pharmaceutical applications as therapeutic agent are hampered because of its poor aqueous solubility. The present study explores the advantages of polymeric micelles composed of block copolymers of methoxypoly(ethylene glycol) (mPEG) and N-(2-hydroxypropyl) methacrylamide (HPMA) modified with monolactate, dilactate and benzoyl side groups to enhance CM solubility and inhibitory activity against cancer cells. Amphiphilic block copolymers, ω-methoxypoly(ethylene glycol)-b-(N-(2-benzoyloxypropyl) methacrylamide) (PEG-HPMA-Bz) were synthesized and characterized by (1)H NMR and GPC. One polymer with a molecular weight of 28,000Da was used to formulate CM and compared with other aromatic substituted polymers. CM was loaded by a fast heating method (PEG-HPMA-DL and PEG-HPMA-Bz-L) and a nanoprecipitation method (PEG-HPMA-Bz). Physicochemical characteristics and cytotoxicity/cytocompatibility of the CM loaded polymeric micelles were evaluated. It was found that HPMA-based polymeric micelles significantly enhanced the solubility of CM. The PEG-HPMA-Bz micelles showed the best solubilization properties. CM loaded polymeric micelles showed sustained release of the loading CM for more than 20days. All of CM loaded polymeric micelles formulations showed a significantly potent cytotoxic effect against three cancer cell lines. HPMA-based polymeric micelles are therefore promising nanodelivery systems of CM for cancer therapy. Copyright © 2015 Elsevier B.V. All rights reserved.

Doxorubicin bound to a HPMA copolymer carrier through hydrazone bond is effective also in a cancer cell line with a limited content of lysosomes

Czech Academy of Sciences Publication Activity Database

Říhová, Blanka; Etrych, Tomáš; Pechar, Michal; Jelínková, Markéta; Šťastný, Marek; Hovorka, Ondřej; Kovář, Marek; Ulbrich, Karel

2001-01-01

Roč. 74, - (2001), s. 225-232 ISSN 0168-3659 R&D Projects: GA MZd NC5050; GA ČR GV307/96/K226 Institutional research plan: CEZ:AV0Z5020903 Keywords : HPMA copolymer carrier * proteolytically cleavable bond Subject RIV: EC - Immunology Impact factor: 2.626, year: 2001

Synthesis and properties of star HPMA copolymer nanocarriers synthesised by RAFT polymerisation designed for selective anticancer drug delivery and imaging

Czech Academy of Sciences Publication Activity Database

Chytil, Petr; Koziolová, Eva; Janoušková, Olga; Kostka, Libor; Ulbrich, Karel; Etrych, Tomáš

2015-01-01

Roč. 15, č. 6 (2015), s. 839-850 ISSN 1616-5187 R&D Projects: GA ČR GPP207/11/P551; GA ČR(CZ) GCP207/12/J030; GA MŠk(CZ) EE2.3.30.0029; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61389013 Keywords : drug delivery systems * HPMA copolymers * pH-controlled release Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.680, year: 2015

Star polymer-drug conjugates with pH-controlled drug release and carrier degradation

Czech Academy of Sciences Publication Activity Database

Kostková, Hana; Schindler, Lucie; Kotrchová, Lenka; Kovář, Marek; Šírová, Milada; Kostka, Libor; Etrych, Tomáš

2017-01-01

Roč. 2017, 3 January (2017), s. 1-10, č. článku 8675435. ISSN 1687-4110 R&D Projects: GA MŠk(CZ) LQ1604 Institutional support: RVO:61389013 ; RVO:61388971 Keywords : star conjugate * HPMA copolymer * doxorubicin Subject RIV: CD - Macromolecular Chemistry; EE - Microbiology, Virology (MBU-M) OBOR OECD: Polymer science; Microbiology (MBU-M) Impact factor: 1.871, year: 2016

CONJUGATED BLOCK-COPOLYMERS FOR ELECTROLUMINESCENT DIODES

NARCIS (Netherlands)

Hilberer, A; Gill, R.E; Herrema, J.K; Malliaras, G.G; Wildeman, J.; Hadziioannou, G

In this article we review results obtained in our laboratory on the design and study of new light-emitting polymers. We are interested in the synthesis and characterisation of block copolymers with regularly alternating conjugated and non conjugated sequences. The blocks giving rise to luminescence

The same drug but a different mechanism of action: comparison of free doxorubicin with two different N-(2-hydroxypropyl)methacrylamide copolymer-bound doxorubicin conjugates in EL-4 cancer cell line.

Science.gov (United States)

Kovár, Lubomír; Strohalm, Jirí; Chytil, Petr; Mrkvan, Tomás; Kovár, Marek; Hovorka, Ondrej; Ulbrich, Karel; Ríhová, Blanka

2007-01-01

Doxorubicin is one of the most potent anti-tumor drugs with a broad spectrum of use. To reduce its toxic effect and improve its pharmacokinetics, we conjugated it to an HPMA copolymer carrier that enhances its passive accumulation within solid tumors via the EPR effect and decreases its cytotoxicity to normal, noncancer cells. In this study, we compared the antiproliferative, pro-survival, and death signals triggered in EL-4 cancer cells exposed to free doxorubicin and doxorubicin conjugated to a HPMA copolymer carrier via either enzymatically (PK1) or hydrolytically (HYD) degradable bonds. We have previously shown that the intracellular distribution of free doxorubicin, HYD, and PK1 is markedly different. Here, we demonstrated that these three agents greatly differ also in the antiproliferative effect and cell death signals they trigger. JNK phosphorylation sharply increased in cells treated with HYD, while treatment with free doxorubicin moderately decreased and treatment with PK1 even strongly decreased it. On the other hand, treatment with free doxorubicin greatly increased p38 phosphorylation, while PK1 and HYD increased it slightly. PK1 also significantly increased ERK phosphorylation, while both the free doxorubicin and HYD conjugate slightly decreased it. Long-term inhibition of JNK significantly increased both proliferation and viability of EL-4 cells treated with free doxorubicin, showing that the JNK signaling pathway could be critical for mediating cell death in EL-4 cells exposed to free doxorubicin. Both activation of caspase 3 and decreased binding activity of the p50 subunit of NFkappaB were observed in cells treated with free doxorubicin and HYD, while no such effects were seen in cells incubated with PK1. Analysis of the expression of genes involved in apoptosis and regulation of the cell cycle demonstrated that free doxorubicin and HYD have very similar mechanisms of action, while PK1 has very different characteristics.

Studies on guanidinated N-3-aminopropyl methacrylamide-N-2-hydroxypropyl methacrylamide co-polymers as gene delivery carrier.

Science.gov (United States)

Qin, Zhu; Liu, Wei; Guo, Liang; Li, Xinsong

2012-01-01

Guanidinated N-3-aminopropyl methacrylamide (APMA)-N-2-hydroxypropyl methacrylamide (HPMA) co-polymers were prepared and evaluated to develop novel non-viral gene transfection carriers. The co-polymers were synthesized via radical co-polymerization of APMA and HPMA followed by total guanidination of amino groups, which employed guanidinated APMA (GPMA) for increasing cell-penetrating and HPMA as the positive shielding content. The molecular weight of guanidinated APMA-HPMA co-polymers (GPMA-HPMA) was determined by static light scattering. Furthermore, cytotoxicity and transfection experiments of GPMA-HPMA/pDNA complexes were conducted. A significant decrease of their parent cytotoxicity and an efficient transfection at relative low charge ratios were observed. The cellular distribution of most GPMA-HPMA/pDNA complexes was partially localized in the nucleus, as indicated by confocal laser scanning microscopy. The guanidination strategy employed may lead to non-viral gene delivery carriers that combine satisfactory transfection efficiency and cytotoxicity, which contribute to their cell-penetrating ability.

Comparison between linear and star-like HPMA conjugated pirarubicin (THP) in pharmacokinetics and antitumor activity in tumor bearing mice

Czech Academy of Sciences Publication Activity Database

Nakamura, H.; Koziolová, Eva; Etrych, Tomáš; Chytil, Petr; Fang, J.; Ulbrich, Karel; Maeda, H.

2015-01-01

Roč. 90, February (2015), s. 90-96 ISSN 0939-6411 R&D Projects: GA ČR(CZ) GCP207/12/J030; GA ČR GPP207/11/P551; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61389013 Keywords : HPMA polymer conjugate * pirarubicin (THP) * acid-cleavable linkage Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.975, year: 2015

Comparison of the pharmacological and biological properties of HPMA copolymer-pirarubicin conjugates: A single-chain copolymer conjugate and its biodegradable tandem-diblock copolymer conjugate

Czech Academy of Sciences Publication Activity Database

Etrych, Tomáš; Tsukigawa, K.; Nakamura, H.; Chytil, Petr; Fang, J.; Ulbrich, Karel; Otagiri, M.; Maeda, H.

2017-01-01

Roč. 106, 30 August (2017), s. 10-19 ISSN 0928-0987 R&D Projects: GA ČR(CZ) GA15-02986S; GA MŠk(CZ) LQ1604; GA MŠk(CZ) ED1.1.00/02.0109 Grant - others:AV ČR,Japan Society for the Promotion of Science(CZ) JSPS-16-05 Program:Bilaterální spolupráce Institutional support: RVO:61389013 Keywords : pirarubicin * PHPMA conjugate * tandem-diblock PHPMA conjugate Subject RIV: FR - Pharmacology ; Medidal Chemistry OBOR OECD: Pharmacology and pharmacy Impact factor: 3.756, year: 2016

Treatment with HPMA copolymer-based doxorubicin conjugate containing human immunoglobulin induces long-lasting systemic anti-tumour immunity in mice

Czech Academy of Sciences Publication Activity Database

Šírová, Milada; Strohalm, Jiří; Šubr, Vladimír; Plocová, Daniela; Rossmann, Pavel; Mrkvan, Tomáš; Ulbrich, Karel; Říhová, Blanka

2007-01-01

Roč. 56, - (2007), s. 35-47 ISSN 0340-7004 R&D Projects: GA MŠk 1M0505; GA ČR GA305/05/2268 Institutional research plan: CEZ:AV0Z50200510; CEZ:AV0Z40500505 Keywords : targered tumour therapy * hpma * human immunoglobulin Subject RIV: EE - Microbiology, Virology Impact factor: 3.728, year: 2007

The comparison of in vivo properties of water-soluble HPMA-based polymer conjugates with doxorubicin prepared by controlled RAFT or free radical polymerization

Czech Academy of Sciences Publication Activity Database

Chytil, Petr; Šírová, Milada; Koziolová, Eva; Ulbrich, Karel; Říhová, Blanka; Etrych, Tomáš

2015-01-01

Roč. 64, Suppl. 1 (2015), S41-S49 ISSN 0862-8408 R&D Projects: GA MŠk(CZ) EE2.3.30.0029; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61389013 ; RVO:61388971 Keywords : HPMA copolymers * RAFT polymerization * drug delivery system Subject RIV: EB - Genetics ; Molecular Biology; CE - Biochemistry (MBU-M) Impact factor: 1.643, year: 2015 http://www.biomed.cas.cz/physiolres/pdf/64%20Suppl%201/64_S41.pdf

Direct Cytoplasmic Delivery and Nuclear Targeting Delivery of HPMA-MT Conjugates in a Microtubules Dependent Fashion.

Science.gov (United States)

Zhong, Jiaju; Zhu, Xi; Luo, Kui; Li, Lian; Tang, Manlin; Liu, Yanxi; Zhou, Zhou; Huang, Yuan

2016-09-06

As the hearts of tumor cells, the nucleus is the ultimate target of many chemotherapeutic agents and genes. However, nuclear drug delivery is always hampered by multiple intracellular obstacles, such as low efficiency of lysosome escape and insufficient nuclear trafficking. Herein, an N-(2-hydroxypropyl) methacrylamide (HPMA) polymer-based drug delivery system was designed, which could achieve direct cytoplasmic delivery by a nonendocytic pathway and transport into the nucleus in a microtubules dependent fashion. A special targeting peptide (MT), derived from an endogenic parathyroid hormone-related protein, was conjugated to the polymer backbone, which could accumulate into the nucleus a by microtubule-mediated pathway. The in vitro studies found that low temperature and NaN3 could not influence the cell internalization of the conjugates. Besides, no obvious overlay of the conjugates with lysosome demonstrated that the polymer conjugates could enter the tumor cell cytoplasm by a nonendocytic pathway, thus avoiding the drug degradation in the lysosome. Furthermore, after suppression of the microtubule dynamics with microtubule stabilizing docetaxel (DTX) and destabilizing nocodazole (Noc), the nuclear accumulation of polymeric conjugates was significantly inhibited. Living cells fluorescence recovery after photobleaching study found that the nuclear import rate of conjugates was 2-fold faster compared with the DTX and Noc treated groups. These results demonstrated that the conjugates transported into the nucleus in a microtubules dependent way. Therefore, in addition to direct cytoplasmic delivery, our peptide conjugated polymeric platform could simultaneously mediate nuclear drug accumulation, which may open a new path for further intracellular genes/peptides delivery.

The structure-dependent toxicity, pharmacokinetics and anti-tumour activity of HPMA copolymer conjugates in the treatment of solid tumours and leukaemia

Czech Academy of Sciences Publication Activity Database

Tomalová, Barbora; Šírová, Milada; Rossmann, Pavel; Pola, Robert; Strohalm, Jiří; Chytil, Petr; Černý, Viktor; Tomala, Jakub; Kabešová, Martina; Říhová, Blanka; Ulbrich, Karel; Etrych, Tomáš; Kovář, Marek

2016-01-01

Roč. 223, 10 February (2016), s. 1-10 ISSN 0168-3659 R&D Projects: GA ČR(CZ) GAP301/11/0325; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61388971 ; RVO:61389013 Keywords : HPMA * Doxorubicin * Structure Subject RIV: EE - Microbiology, Virology; CD - Macromolecular Chemistry (UMCH-V) Impact factor: 7.786, year: 2016

HPMA-based block copolymers promote differential drug delivery kinetics for hydrophobic and amphiphilic molecules.

Science.gov (United States)

Tomcin, Stephanie; Kelsch, Annette; Staff, Roland H; Landfester, Katharina; Zentel, Rudolf; Mailänder, Volker

2016-04-15

We describe a method how polymeric nanoparticles stabilized with (2-hydroxypropyl)methacrylamide (HPMA)-based block copolymers are used as drug delivery systems for a fast release of hydrophobic and a controlled release of an amphiphilic molecule. The versatile method of the miniemulsion solvent-evaporation technique was used to prepare polystyrene (PS) as well as poly-d/l-lactide (PDLLA) nanoparticles. Covalently bound or physically adsorbed fluorescent dyes labeled the particles' core and their block copolymer corona. Confocal laser scanning microscopy (CLSM) in combination with flow cytometry measurements were applied to demonstrate the burst release of a fluorescent hydrophobic drug model without the necessity of nanoparticle uptake. In addition, CLSM studies and quantitative calculations using the image processing program Volocity® show the intracellular detachment of the amphiphilic block copolymer from the particles' core after uptake. Our findings offer the possibility to combine the advantages of a fast release for hydrophobic and a controlled release for an amphiphilic molecule therefore pointing to the possibility to a 'multi-step and multi-site' targeting by one nanocarrier. We describe thoroughly how different components of a nanocarrier end up in cells. This enables different cargos of a nanocarrier having a consecutive release and delivery of distinct components. Most interestingly we demonstrate individual kinetics of distinct components of such a system: first the release of a fluorescent hydrophobic drug model at contact with the cell membrane without the necessity of nanoparticle uptake. Secondly, the intracellular detachment of the amphiphilic block copolymer from the particles' core after uptake occurs. This offers the possibility to combine the advantages of a fast release for a hydrophobic substance at the time of interaction of the nanoparticle with the cell surface and a controlled release for an amphiphilic molecule later on therefore

High-molecular-weight HPMA-based polymer drug carriers for delivery to tumor

Czech Academy of Sciences Publication Activity Database

Kostka, Libor; Etrych, Tomáš

2016-01-01

Roč. 65, Suppl. 2 (2016), S179-S190 ISSN 0862-8408 R&D Projects: GA MŠk(CZ) LO1507 Institutional support: RVO:61389013 Keywords : nanotherapeutics * pH responsive * HPMA copolymers Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.461, year: 2016 http://www.biomed.cas.cz/physiolres/pdf/65%20Suppl%202/65_S179.pdf

Self-Assembly and Crystallization of Conjugated Block Copolymers

Science.gov (United States)

Davidson, Emily Catherine

This dissertation demonstrates the utility of molecular design in conjugated polymers to create diblock copolymers that robustly self-assemble in the melt and confine crystallization upon cooling. This work leverages the model conjugated polymer poly(3-(2'-ethyl)hexylthiophene) (P3EHT), which features a branched side chain, resulting in a dramatically reduced melting temperature (Tm 80°C) relative to the widely-studied poly(3-hexylthiophene) (P3HT) (Tm 200°C). This reduced melting temperature permits an accessible melt phase, without requiring that the segregation strength (chiN) be dramatically increased. Thus, diblock copolymers containing P3EHT demonstrate robust diblock copolymer self-assembly in the melt over a range of compositions and morphologies. Furthermore, confined crystallization in the case of both glassy (polystyrene (PS) matrix block) and soft (polymethylacrylate (PMA) matrix block) confinement is studied, with the finding that even in soft confinement, crystallization is constrained within the diblock microdomains. This success demonstrates the strategy of leveraging molecular design to decrease the driving force for crystallization as a means to achieving robust self-assembly and confined crystallization in conjugated block copolymers. Importantly, despite the relatively flexible nature of P3EHT in the melt, the diblock copolymer phase behavior appears to be significantly impacted by the stiffness (persistence length of 3 nm) of the P3EHT chain compared to the coupled amorphous blocks (persistence length 0.7 nm). In particular, it is shown that the synthesized morphologies are dominated by a very large composition window for lamellar geometries (favored at high P3EHT volume fractions); cylindrical geometries are favored when P3EHT is the minority fraction. This asymmetry of the composition window is attributed to impact of conformational asymmetry (the difference in chain stiffness, as opposed to shape) between conjugated and amorphous blocks

Targeted polymeric anticancer drugs based on HPMA in therapy of HNSCC

Czech Academy of Sciences Publication Activity Database

Bouček, J.; Betka, J.; Strohalm, Jiří; Plocová, Daniela; Šubr, Vladimír; Mrkvan, Tomáš; Ulbrich, Karel; Říhová, Blanka

2006-01-01

Roč. 55, Suppl. 1 (2006), s. 212-213 ISSN 1210-7867. [World Congress of International Federation of Head and Neck Oncologic Societies /3./. 27.06.2006-01.07.2006, Prague] Institutional research plan: CEZ:AV0Z40500505 Keywords : HPMA * HNSCC * polymer drug conjugates Subject RIV: CE - Biochemistry

Drug-conjugated PLA-PEG-PLA copolymers: a novel approach for controlled delivery of hydrophilic drugs by micelle formation.

Science.gov (United States)

Danafar, H; Rostamizadeh, K; Davaran, S; Hamidi, M

2017-12-01

A conjugate of the antihypertensive drug, lisinopril, with triblock poly(lactic acid)-poly(ethylene glycol)-poly(lactic acid) (PLA-PEG-PLA) copolymer was synthesized by the reaction of PLA-PEG-PLA copolymer with lisinopril in the presence of dicyclohexylcarbodiimide and dimethylaminopyridine. The conjugated copolymer was characterized in vitro by hydrogen nuclear magnetic resonance (HNMR), Fourier transform infrared (FTIR), differential scanning calorimetry (DSC) and gel permeation chromatography (GPC) techniques. Then, the lisinopril conjugated PLA-PEG-PLA were self-assembled into micelles in aqueous solution. The resulting micelles were characterized further by various techniques such as dynamic light scattering (DLS) and atomic force microscopy (AFM). The results revealed that the micelles formed by the lisinopril-conjugated PLA-PEG-PLA have spherical structure with the average size of 162 nm. The release behavior of conjugated copolymer, micelles and micelles physically loaded by lisinopril were compared in different media. In vitro release study showed that in contrast to physically loaded micelles, the release rate of micelles consisted of the conjugated copolymer was dependent on pH of media where it was higher at lower pH compared to the neutral medium. Another feature of the conjugated micelles was their more sustained release profile compared to the lisinopril-conjugated copolymer and physically loaded micelles.

Two step mechanisms of tumor selective delivery of N-(2-hydroxypropyl)methacrylamide copolymer conjugated with pirarubicin via an acid-cleavable linkage

Czech Academy of Sciences Publication Activity Database

Nakamura, H.; Etrych, Tomáš; Chytil, Petr; Ohkubo, M.; Fang, J.; Ulbrich, Karel; Maeda, H.

2014-01-01

Roč. 174, 28 January (2014), s. 81-87 ISSN 0168-3659 Grant - others:AV ČR(CZ) AP0802 Program:Akademická prémie - Praemium Academiae Institutional support: RVO:61389013 Keywords : HPMA polymer conjugate * pirarubicin (THP) * tumor selectivity Subject RIV: CD - Macromolecular Chemistry Impact factor: 7.705, year: 2014

Novel IL-2-Poly(HPMA)Nanoconjugate Based Immunotherapy

Czech Academy of Sciences Publication Activity Database

Votavová, Petra; Tomala, Jakub; Šubr, Vladimír; Strohalm, Jiří; Ulbrich, Karel; Říhová, Blanka; Kovář, Marek

2015-01-01

Roč. 11, č. 9 (2015), s. 1662-1673 ISSN 1550-7033 R&D Projects: GA ČR GA13-12885S; GA MŠk(CZ) ED1.1.00/02.0109 Grant - others:AV ČR(CZ) AP0802 Program:Akademická prémie - Praemium Academiae Institutional support: RVO:61388971 ; RVO:61389013 Keywords : Interleukin-2 * N-(2-hydroxypropyl)Methacrylamide * Poly(HPMA) Conjugate Subject RIV: EC - Immunology; EC - Immunology (UMCH-V) Impact factor: 3.929, year: 2015

Aqueous dispersion polymerization: a new paradigm for in situ block copolymer self-assembly in concentrated solution.

Science.gov (United States)

Sugihara, Shinji; Blanazs, Adam; Armes, Steven P; Ryan, Anthony J; Lewis, Andrew L

2011-10-05

Reversible addition-fragmentation chain transfer polymerization has been utilized to polymerize 2-hydroxypropyl methacrylate (HPMA) using a water-soluble macromolecular chain transfer agent based on poly(2-(methacryloyloxy)ethylphosphorylcholine) (PMPC). A detailed phase diagram has been elucidated for this aqueous dispersion polymerization formulation that reliably predicts the precise block compositions associated with well-defined particle morphologies (i.e., pure phases). Unlike the ad hoc approaches described in the literature, this strategy enables the facile, efficient, and reproducible preparation of diblock copolymer spheres, worms, or vesicles directly in concentrated aqueous solution. Chain extension of the highly hydrated zwitterionic PMPC block with HPMA in water at 70 °C produces a hydrophobic poly(2-hydroxypropyl methacrylate) (PHPMA) block, which drives in situ self-assembly to form well-defined diblock copolymer spheres, worms, or vesicles. The final particle morphology obtained at full monomer conversion is dictated by (i) the target degree of polymerization of the PHPMA block and (ii) the total solids concentration at which the HPMA polymerization is conducted. Moreover, if the targeted diblock copolymer composition corresponds to vesicle phase space at full monomer conversion, the in situ particle morphology evolves from spheres to worms to vesicles during the in situ polymerization of HPMA. In the case of PMPC(25)-PHPMA(400) particles, this systematic approach allows the direct, reproducible, and highly efficient preparation of either block copolymer vesicles at up to 25% solids or well-defined worms at 16-25% solids in aqueous solution.

Effect of physicochemical modification on the biodistribution and tumor accumulation of HPMA copolymers

Czech Academy of Sciences Publication Activity Database

Lammers, T.; Kühnlein, R.; Kissel, M.; Šubr, Vladimír; Etrych, Tomáš; Pola, Robert; Pechar, Michal; Ulbrich, Karel; Storm, G.; Huber, P. E.; Peschke, P.

2005-01-01

Roč. 110, č. 1 (2005), s. 103-118 ISSN 0168-3659 R&D Projects: GA ČR GA204/05/2255 Institutional research plan: CEZ:AV0Z40500505 Keywords : HPMA * EPR * drug delivery Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.696, year: 2005

Radioactive labeling of defined HPMA-based polymeric structures using [18F]FETos for in vivo imaging by positron emission tomography

DEFF Research Database (Denmark)

Herth, Matthias Manfred; Barz, Matthias; Moderegger, Dorothea

2009-01-01

and tyramine (3%) to form (18)F-labelable HPMA-polymer precursors. The labeling procedure of the phenolic tyramine moieties via the secondary labeling synthon 2-[(18)F]fluoroethyl-1-tosylate ([(18)F]FETos) provided radiochemical fluoroalkylation yields of ∼80% for block copolymers and >50% for random polymer...

Diketopyrrolopyrrole-diketopyrrolopyrrole-based conjugated copolymer for high-mobility organic field-effect transistors

KAUST Repository

Kanimozhi, Catherine K.

2012-10-10

In this communication, we report the synthesis of a novel diketopyrrolopyrrole-diketopyrrolopyrrole (DPP-DPP)-based conjugated copolymer and its application in high-mobility organic field-effect transistors. Copolymerization of DPP with DPP yields a copolymer with exceptional properties such as extended absorption characteristics (up to ∼1100 nm) and field-effect electron mobility values of >1 cm 2 V -1 s -1. The synthesis of this novel DPP-DPP copolymer in combination with the demonstration of transistors with extremely high electron mobility makes this work an important step toward a new family of DPP-DPP copolymers for application in the general area of organic optoelectronics. © 2012 American Chemical Society.

The structure of polymer carriers controls the efficacy of the experimental combination treatment of tumors with HPMA copolymer conjugates carrying doxorubicin and docetaxel

Czech Academy of Sciences Publication Activity Database

Šírová, Milada; Strohalm, Jiří; Chytil, Petr; Lidický, Ondřej; Tomala, Jakub; Říhová, Blanka; Etrych, Tomáš

2017-01-01

Roč. 246, JAN 28 (2017), s. 1-11 ISSN 0168-3659 R&D Projects: GA ČR(CZ) GA14-12742S; GA ČR(CZ) GA15-02986S; GA MŠk(CZ) LQ1604; GA MŠk(CZ) ED1.1.00/02.0109; GA MZd(CZ) NV16-28600A; GA ČR(CZ) GAP301/12/1254 Institutional support: RVO:61388971 ; RVO:61389013 Keywords : Drug delivery * HPMA * Doxorubicin Subject RIV: EC - Immunology; CD - Macromolecular Chemistry (UMCH-V) OBOR OECD: Immunology; Polymer science (UMCH-V) Impact factor: 7.786, year: 2016

Diketopyrrolopyrrole-diketopyrrolopyrrole-based conjugated copolymer for high-mobility organic field-effect transistors

KAUST Repository

Kanimozhi, Catherine K.; Yaacobi-Gross, Nir; Chou, Kang Wei; Amassian, Aram; Anthopoulos, Thomas D.; Patil, Satish P.

2012-01-01

In this communication, we report the synthesis of a novel diketopyrrolopyrrole-diketopyrrolopyrrole (DPP-DPP)-based conjugated copolymer and its application in high-mobility organic field-effect transistors. Copolymerization of DPP with DPP yields a

Elucidation of the Structure Formation of Polymer-Conjugated Proteins in Solution and Block Copolymer Templates

Science.gov (United States)

Ferebee, Rachel L.

The broader technical objective of this work is to contribute to the development of enzyme-functionalized nanoporous membranes that can function as autonomous and target selective dynamic separators. The scientific objective of the research performed within this thesis is to elucidate the parameters that control the mixing of proteins in organic host materials and in block copolymers templates in particular. A "biomimetic" membrane system that uses enzymes to selectively neutralize targets and trigger a change in permeability of nanopores lined with a pH-responsive polymer has been fabricated and characterized. Mechanical and functional stability, as well as scalability, have been demonstrated for this system. Additional research has focused on the role of polymeric ligands on the solubility characteristics of the model protein, Bovine Serum Albumin (BSA). For this purpose BSA was conjugated with poly(ethylene glycol) (PEG) ligands of varied degree of polymerization and grafting density. Combined static and dynamic light scattering was used (in conjunction with MALDI-TOF) to determine the second virial coefficient in PBS solutions. At a given mass fraction PEG or average number of grafts, the solubility of BSA-PEG conjugates is found to increase with the degree of polymerization of conjugated PEG. This result informs the synthesis of protein-conjugate systems that are optimized for the fabrication of block copolymer blend materials with maximum protein loading. Blends of BSA-PEG conjugates and block copolymer (BCP) matrices were fabricated to evaluate the dispersion morphology and solubility limits in a model system. Electron microscopy was used to evaluate the changes in lamellar spacing with increased filling fraction of BSA-PEG conjugates.

Effect of radiotherapy and hyperthermia on the tumor accumulation of HPMA copolymer-based drug delivery systems

Czech Academy of Sciences Publication Activity Database

Lammers, T.; Peschke, P.; Kühnlein, R.; Šubr, Vladimír; Ulbrich, Karel; Debus, J.; Huber, P. E.; Hennink, W. E.; Storm, G.

2007-01-01

Roč. 117, č. 3 (2007), s. 333-341 ISSN 0168-3659 R&D Projects: GA ČR GA204/05/2255 Institutional research plan: CEZ:AV0Z40500505 Keywords : HPMA * drug delivery * tumor targeting Subject RIV: CD - Macromolecular Chemistry Impact factor: 4.756, year: 2007

Complexation of anionic copolymers of acrylamide and N-(2-hydroxypropyl)methacrylamide with aminoglycoside antibiotics

Science.gov (United States)

Solovskii, M. V.; Tarabukina, E. B.; Amirova, A. I.; Zakharova, N. V.; Smirnova, M. Yu.; Gavrilova, I. I.

2014-03-01

The complexation of aminoglycoside antibiotics neomycin, gentamicin, kanamycin, and amikacin in the form of free bases with carboxyl- and sulfo-containing copolymers of acrylamide and N-(2-hydroxypropyl)methacrylamide (HPMA) in water and water-salt solutions is studied by means of viscometry, equilibrium dialysis, potentiometric titration, and molecular hydrodynamics. Factors influencing the stability of formed copolymer-antibiotic complexes and determinations of their toxicity are established.

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

Targeting angiogenesis-dependent calcified neoplasms using combined polymer therapeutics.

Directory of Open Access Journals (Sweden)

Ehud Segal

Full Text Available There is an immense clinical need for novel therapeutics for the treatment of angiogenesis-dependent calcified neoplasms such as osteosarcomas and bone metastases. We developed a new therapeutic strategy to target bone metastases and calcified neoplasms using combined polymer-bound angiogenesis inhibitors. Using an advanced "living polymerization" technique, the reversible addition-fragmentation chain transfer (RAFT, we conjugated the aminobisphosphonate alendronate (ALN, and the potent anti-angiogenic agent TNP-470 with N-(2-hydroxypropylmethacrylamide (HPMA copolymer through a Glycine-Glycine-Proline-Norleucine linker, cleaved by cathepsin K, a cysteine protease overexpressed at resorption sites in bone tissues. In this approach, dual targeting is achieved. Passive accumulation is possible due to the increase in molecular weight following polymer conjugation of the drugs, thus extravasating from the tumor leaky vessels and not from normal healthy vessels. Active targeting to the calcified tissues is achieved by ALN's affinity to bone mineral.The anti-angiogenic and antitumor potency of HPMA copolymer-ALN-TNP-470 conjugate was evaluated both in vitro and in vivo. We show that free and conjugated ALN-TNP-470 have synergistic anti-angiogenic and antitumor activity by inhibiting proliferation, migration and capillary-like tube formation of endothelial and human osteosarcoma cells in vitro. Evaluation of anti-angiogenic, antitumor activity and body distribution of HPMA copolymer-ALN-TNP-470 conjugate was performed on severe combined immunodeficiency (SCID male mice inoculated with mCherry-labeled MG-63-Ras human osteosarcoma and by modified Miles permeability assay. Our targeted bi-specific conjugate reduced VEGF-induced vascular hyperpermeability by 92% and remarkably inhibited osteosarcoma growth in mice by 96%.This is the first report to describe a new concept of a narrowly-dispersed combined polymer therapeutic designed to target both tumor and

Antitumor activity of IL-2/anti-IL-2 mAb immunocomplexes exerts synergism with that of N-(2-hydroxypropyl)methacrylamide copolymer-bound doxorubicin conjugate due to its low immunosuppressive activity

Czech Academy of Sciences Publication Activity Database

Tomala, Jakub; Chmelová, Helena; Strohalm, Jiří; Ulbrich, Karel; Šírová, Milada; Říhová, Blanka; Kovář, Marek

2011-01-01

Roč. 129, č. 8 (2011), s. 2002-2012 ISSN 0020-7136 R&D Projects: GA AV ČR IAA500200712; GA ČR GD310/08/H077; GA ČR GP301/07/P192; GA MŠk 1M0505 Institutional research plan: CEZ:AV0Z50200510; CEZ:AV0Z40500505 Keywords : IL-2 immunocomplexes * NK cells * HPMA copolymer-bound doxorubicin Subject RIV: EC - Immunology Impact factor: 5.444, year: 2011

PCL-PEG graft copolymers with tunable amphiphilicity as efficient drug delivery systems

Czech Academy of Sciences Publication Activity Database

Al Samad, A.; Bethry, A.; Koziolová, Eva; Netopilík, Miloš; Etrych, Tomáš; Bakkour, Y.; Coudane, J.; El Omar, F.; Nottelet, B.

2016-01-01

Roč. 4, č. 37 (2016), s. 6228-6239 ISSN 2050-750X R&D Projects: GA MŠk(CZ) LO1507; GA ČR(CZ) GA15-02986S Institutional support: RVO:61389013 Keywords : HPMA copolymer * tumor * micelle Subject RIV: CD - Macromolecular Chemistry Impact factor: 4.543, year: 2016

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

Cubosome formulations stabilized by a dansyl-conjugated block copolymer for possible nanomedicine applications.

Science.gov (United States)

Murgia, Sergio; Falchi, Angela Maria; Meli, Valeria; Schillén, Karin; Lippolis, Vito; Monduzzi, Maura; Rosa, Antonella; Schmidt, Judith; Talmon, Yeshayahu; Bizzarri, Ranieri; Caltagirone, Claudia

2015-05-01

We present here an innovative, fluorescent, monoolein-based cubosome dispersion. Rather than embedded within the monoolein palisade, the fluorescent imaging agent, namely dansyl, was conjugated to the terminal ethylene oxide moieties of the block copolymer Pluronic F108. We discuss the physicochemical and photophysical properties of this fluorescent Pluronic and of a cubosome formulation stabilized by a mixture of dansyl-conjugated and non-conjugated Pluronic, also including an anticancer drug (quercetin). Furthermore, we performed biocompatibility tests against HeLa cells to assess internalization and cytotoxicity features of this nanoparticles aqueous dispersion. Cryo-TEM, SAXS, and DLS analysis, proved the bicontinuous cubic inner nanostructure and the morphology of this fluorescent cubosome dispersion, while photophysical measurements and biocompatibility results basically validate their potential use for theranostic nanomedicine applications. Copyright © 2015 Elsevier B.V. All rights reserved.

Ultra-Fast RAFT-HDA Click Conjugation: An Efficient Route to High Molecular Weight Block Copolymers.

Science.gov (United States)

Inglis, Andrew J; Stenzel, Martina H; Barner-Kowollik, Christopher

2009-11-02

The use of the reversible addition fragmentation chain transfer-hetero Diels-Alder (RAFT-HDA) click reaction for the modular construction of block copolymers is extended to the generation of high molecular weight materials. Cyclopentadienyl end-functionalized polystyrene (PS-Cp) prepared via both atom transfer radical polymerization (ATRP) and the RAFT process are conjugated to poly(isobornyl acrylate) (PiBoA) (also prepared via RAFT polymerization) to achieve well-defined block copolymers with molecular weights ranging from 34 000 to over 100 000 g · mol(-1) and with small polydispersities (PDI HDA click chemistry can provide access to high molecular weight block copolymers in a simple and straight-forward fashion. Copyright © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Study on radiation grafting of NASI on sephadex and conjugation of the copolymer with BSA

International Nuclear Information System (INIS)

Yi Min; Li Jun; Wei Jinshan; Ha Hongfei

1997-01-01

N-acryloxysuccinimide (NASI) with a function ester group is grafted on Sephadex G75 and Sephadex G50 separately by radiation technology. The radiation grafting conditions including absorbed dose, dose rate, monomer concentration in solvent are investigated. The conjugation reactions between the grafted copolymers Sephadex G75-NASI, and bovine serum albumin (BSA) or Sephadex G50-NASI and bovine serum albumin (BSA) are followed. The experiment results show that the conjugate of Sephadex G75-NASI with larger holes and BSA (M r = 6.6 x 10 4 ) is obtained successfully, however, the Sephadex G50 with small holes can be only conjugated with neutral red (M r = 2.58 x 10 2 )

Chemical states and electronic properties of the interface between aluminium and a photoluminescent conjugated copolymer containing europium complex

International Nuclear Information System (INIS)

Cai, Q.J.; Ling, Q.D.; Li, S.; Zhu, F.R.; Huang, Wei; Kang, E.T.; Neoh, K.G.

2004-01-01

The chemical states and electronic properties of the interface between thermally evaporated aluminium and a photoluminescent conjugated copolymer containing 9,9'-dihexylfluorene and europium complex-chelated benzoate units in the main chain (PF6-Eu(dbm) 2 phen) were studied in situ by X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). The changes in C 1s, Eu 3d, N 1s, and Al 2p core-level lineshapes with progressive deposition of aluminium atoms were carefully monitored. Aluminium was found to interact with the conjugated backbone of the copolymer to form the Al carbide, Al-O-C complex, and Al(III)-N chelate at the interface. In addition, the europium ions were reduced to the metallic state by the deposited aluminium atoms, which were oxidized and chelated by the 1,10-phenanthroline ligands (phen). The changes in chemical states at the interface suggest that the intramolecular energy transfer process in this copolymer had been affected. Moreover, aluminium also interacted with the bulk-adsorbed oxygen, which migrates to the surface in response to the deposition of aluminium atoms, to form a layer of metal oxides. On the other hand, the evolution of the UPS spectra suggests that the π-states of the conjugated system were affected and an unfavorable dipole layer was induced by the deposited aluminium atoms

Molecular detection of HpmA and HlyA hemolysin of uropathogenic Proteus mirabilis.

Science.gov (United States)

Cestari, Silvia Emanoele; Ludovico, Marilucia Santos; Martins, Fernando Henrique; da Rocha, Sérgio Paulo Dejato; Elias, Waldir Pereira; Pelayo, Jacinta Sanchez

2013-12-01

Urinary tract infection (UTI) is one of the bacterial infections frequently documented in humans. Proteus mirabilis is associated with UTI mainly in individuals with urinary tract abnormality or related with vesicular catheterism and it can be difficult to treat because of the formation of stones in the bladder and kidneys. These stones are formed due to the presence of urease synthesized by the bacteria. Another important factor is that P. mirabilis produces hemolysin HpmA, used by the bacteria to damage the kidney tissues. Proteus spp. samples can also express HlyA hemolysin, similar to that found in Escherichia coli. A total of 211 uropathogenic P. mirabilis isolates were analyzed to detect the presence of the hpmA and hpmB genes by the techniques of polymerase chain reaction (PCR) and dot blot and hlyA by PCR. The hpmA and hpmB genes were expressed by the RT-PCR technique and two P. mirabilis isolates were sequenced for the hpmA and hpmB genes. The presence of the hpmA and hpmB genes was confirmed by PCR in 205 (97.15 %) of the 211 isolates. The dot blot confirmed the presence of the hpmA and hpmB genes in the isolates that did not amplify in the PCR. None of the isolates studied presented the hlyA gene. The hpmA and hpmB genes that were sequenced presented 98 % identity with the same genes of the HI4320 P. mirabilis sample. This study showed that the PCR technique has good sensitivity for detecting the hpmA and hpmB genes of P. mirabilis.

Long-circulating and passively tumor-targeted polymer-drug conjugates improve the efficacy and reduce the toxicity of radiochemotherapy

Czech Academy of Sciences Publication Activity Database

Lammers, T.; Šubr, Vladimír; Ulbrich, Karel; Peschke, P.; Huber, P. E.; Hennink, W. E.; Storm, G.; Kiessling, F.

2010-01-01

Roč. 12, č. 9 (2010), B413-B421 ISSN 1438-1656 R&D Projects: GA MŠk 1M0505 Institutional research plan: CEZ:AV0Z40500505 Keywords : HPMA copolymers * targeting * tumor targeting Subject RIV: EI - Biotechnology ; Bionics Impact factor: 1.746, year: 2010

The pH-dependent and enzymatic release of cytarabine from hydrophilic polymer conjugates

Czech Academy of Sciences Publication Activity Database

Pola, Robert; Janoušková, Olga; Etrych, Tomáš

2016-01-01

Roč. 65, Suppl. 2 (2016), S225-S232 ISSN 0862-8408 R&D Projects: GA MŠk(CZ) LO1507 Institutional support: RVO:61389013 Keywords : HPMA copolymers * drug delivery system * nucleoside analogues Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.461, year: 2016 http://www.biomed.cas.cz/physiolres/pdf/65%20Suppl%202/65_S225.pdf

Overcoming multidrug resistance in Dox-resistant neuroblastoma cell lines via treatment with HPMA copolymer conjugates containing anthracyclines and P-gp inhibitors

Czech Academy of Sciences Publication Activity Database

Koziolová, Eva; Janoušková, Olga; Cuchalová, Lucie; Hvězdová, Zuzana; Hraběta, J.; Eckschlager, T.; Sivák, Ladislav; Ulbrich, Karel; Etrych, Tomáš; Šubr, Vladimír

2016-01-01

Roč. 233, 10 July (2016), s. 136-146 ISSN 0168-3659 R&D Projects: GA ČR(CZ) GAP301/12/1254; GA MŠk(CZ) LO1507 Institutional support: RVO:61389013 ; RVO:61388971 Keywords : N-(2-hydroxypropyl)methacrylamide copolymers * multidrug resistance * P-glycoprotein inhibitors Subject RIV: CD - Macromolecular Chemistry ; FD - Oncology ; Hematology (MBU-M) Impact factor: 7.786, year: 2016

Electrical characterization of fluorinated benzothiadiazole based conjugated copolymer – a promising material for high-performance solar cells

Directory of Open Access Journals (Sweden)

J. Toušek

2015-12-01

Full Text Available Measurements of electrical conductivity, electron work function, carrier mobility of holes and the diffusion length of excitons were performed on samples of conjugated polymers relevant to polymer solar cells. A state of the art fluorinated benzothiadiazole based conjugated copolymer (PBDTTHD − DTBTff was studied and benchmarked against the reference polymer poly-3-hexylthiophene (P3HT. We employed, respectively, four electrode conductivity measurements, Kelvin probe work function measurements, carrier mobility using charge extraction by linearly increasing voltage (CELIV measurements and diffusion length determinaton using surface photovoltage measurements.

Improved Tumor-Specific Drug Accumulation by Polymer Therapeutics with pH-Sensitive Drug Release Overcomes Chemotherapy Resistance.

Science.gov (United States)

Heinrich, Anne-Kathrin; Lucas, Henrike; Schindler, Lucie; Chytil, Petr; Etrych, Tomáš; Mäder, Karsten; Mueller, Thomas

2016-05-01

The success of chemotherapy is limited by poor selectivity of active drugs combined with occurrence of tumor resistance. New star-like structured N-(2-hydroxypropyl) methacrylamide (HPMA) copolymer-based drug delivery systems containing doxorubicin attached via a pH-sensitive hydrazone bond were designed and investigated for their ability to overcome chemotherapy resistance. These conjugates combine two strategies to achieve a high drug concentration selectively at the tumor site: (I) high accumulation by passive tumor targeting based on enhanced permeability and retention effect and (II) pH-sensitive site-specific drug release due to an acidic tumor microenvironment. Mice bearing doxorubicin-resistant xenograft tumors were treated with doxorubicin, PBS, poly HPMA (pHPMA) precursor or pHPMA-doxorubicin conjugate at different equivalent doses of 5 mg/kg bodyweight doxorubicin up to a 7-fold total dose using different treatment schedules. Intratumoral drug accumulation was analyzed by fluorescence imaging utilizing intrinsic fluorescence of doxorubicin. Free doxorubicin induced significant toxicity but hardly any tumor-inhibiting effects. Administering at least a 3-fold dose of pHPMA-doxorubicin conjugate was necessary to induce a transient response, whereas doses of about 5- to 6-fold induced strong regressions. Tumors completely disappeared in some cases. The onset of response was differential delayed depending on the tumor model, which could be ascribed to distinct characteristics of the microenvironment. Further fluorescence imaging-based analyses regarding underlying mechanisms of the delayed response revealed a related switch to a more supporting intratumoral microenvironment for effective drug release. In conclusion, the current study demonstrates that the concept of tumor site-restricted high-dose chemotherapy is able to overcome therapy resistance. Mol Cancer Ther; 15(5); 998-1007. ©2016 AACR. ©2016 American Association for Cancer Research.

Synergistic effect of EMF-BEMER-type pulsed weak electromagnetic field and HPMA-bound doxorubicin on mouse EL4 T-cell lymphoma.

Science.gov (United States)

Říhová, Blanka; Etrych, Tomáš; Šírová, Milada; Tomala, Jakub; Ulbrich, Karel; Kovář, Marek

2011-12-01

We have investigated the effects of low-frequency pulsed electromagnetic field (LF-EMF) produced by BEMER device on experimental mouse T-cell lymphoma EL4 growing on conventional and/or athymic (nude) mice. Exposure to EMF-BEMER slowed down the growth of tumor mass and prolonged the survival of experimental animals. The effect was more pronounced in immuno-compromised nude mice compared to conventional ones. Acceleration of tumor growth was never observed. No measurable levels of Hsp 70 or increased levels of specific anti-EL4 antibodies were detected in the serum taken from experimental mice before and at different intervals during the experiment, i.e. before solid tumor appeared, at the time of its aggressive growth, and at the terminal stage of the disease. A significant synergizing antitumor effect was seen when EL4 tumor-bearing mice were simultaneously exposed to EMF-BEMER and treated with suboptimal dose of synthetic HPMA copolymer-based doxorubicin, DOX(HYD)-HPMA. Such a combination may be especially useful for heavily treated patients suffering from advanced tumor and requiring additional aggressive chemotherapy which, however, at that time could represent almost life-threatening way of medication.

Impact of molecular weight and degree of conjugation on the thermodynamics of DNA complexation and stability of polyethylenimine-graft-poly(ethylene glycol) copolymers.

Science.gov (United States)

Smith, Ryan J; Beck, Rachel W; Prevette, Lisa E

2015-01-01

Poly(ethylene glycol) (PEG) is often conjugated to polyethylenimine (PEI) to provide colloidal stability to PEI-DNA polyplexes and shield charge leading to toxicity. Here, a library of nine cationic copolymers was synthesized by grafting three molecular weights (750, 2000, 5000Da) of PEG to linear PEI at three conjugation ratios. Using isothermal titration calorimetry, we have quantified the thermodynamics of the associations between the copolymers and DNA and determined the extent to which binding is hindered as a function of PEG molecular weight and conjugation ratio. Low conjugation ratios of 750Da PEG to PEI resulted in little decrease in DNA affinity, but a significant decrease-up to two orders of magnitude-was found for the other copolymers. We identified limitations in determination of affinity using indirect assays (electrophoretic mobility shift and ethidium bromide exclusion) commonly used in the field. Dynamic light scattering of the DNA complexes at physiological ionic strength showed that PEI modifications that did not reduce DNA affinity also did not confer significant colloidal stability, a finding that was supported by calorimetric data on the aggregation process. These results quantify the DNA interaction thermodynamics of PEGylated polycations for the first time and indicate that there is an optimum PEG chain length and degree of substitution in the design of agents that have desirable properties for effective in vivo gene delivery. Copyright © 2015 Elsevier B.V. All rights reserved.

Synthesis of a conjugated pyrrolopyridazinedione–benzodithiophene (PPD–BDT) copolymer and its application in organic and hybrid solar cells

KAUST Repository

Knall, Astrid-Caroline

2017-03-30

Herein, we describe the synthesis and characterization of a conjugated donor–acceptor copolymer consisting of a pyrrolopyridazinedione (PPD) acceptor unit, and a benzodithiophene (BDT) donor unit. The polymerization was done via a Stille cross-coupling polycondensation. The resulting PPD–BDT copolymer revealed an optical bandgap of 1.8 eV and good processability from chlorobenzene solutions. In an organic solar cell in combination with PC70BM, the polymer led to a power conversion efficiency of 4.5%. Moreover, the performance of the copolymer was evaluated in polymer/nanocrystal hybrid solar cells using non-toxic CuInS2 nanocrystals as inorganic phase, which were prepared from precursors directly in the polymer matrix without using additional capping ligands. The PPD–BDT/CuInS2 hybrid solar cells showed comparably high photovoltages and a power conversion efficiency of 2.2%.Graphical abstract

Synthesis of a conjugated pyrrolopyridazinedione-benzodithiophene (PPD-BDT) copolymer and its application in organic and hybrid solar cells.

Science.gov (United States)

Knall, Astrid-Caroline; Jones, Andrew O F; Kunert, Birgit; Resel, Roland; Reishofer, David; Zach, Peter W; Kirkus, Mindaugas; McCulloch, Iain; Rath, Thomas

2017-01-01

Herein, we describe the synthesis and characterization of a conjugated donor-acceptor copolymer consisting of a pyrrolopyridazinedione (PPD) acceptor unit, and a benzodithiophene (BDT) donor unit. The polymerization was done via a Stille cross-coupling polycondensation. The resulting PPD-BDT copolymer revealed an optical bandgap of 1.8 eV and good processability from chlorobenzene solutions. In an organic solar cell in combination with PC 70 BM, the polymer led to a power conversion efficiency of 4.5%. Moreover, the performance of the copolymer was evaluated in polymer/nanocrystal hybrid solar cells using non-toxic CuInS 2 nanocrystals as inorganic phase, which were prepared from precursors directly in the polymer matrix without using additional capping ligands. The PPD-BDT/CuInS 2 hybrid solar cells showed comparably high photovoltages and a power conversion efficiency of 2.2%.

Study of the therapeutic benefit of cationic copolymer administration to vascular endothelium under mechanical stress

Science.gov (United States)

Giantsos-Adams, Kristina; Lopez-Quintero, Veronica; Kopeckova, Pavla; Kopecek, Jindrich; Tarbell, John M.; Dull, Randal

2015-01-01

Pulmonary edema and the associated increases in vascular permeability continue to represent a significant clinical problem in the intensive care setting, with no current treatment modality other than supportive care and mechanical ventilation. Therapeutic compound(s) capable of attenuating changes in vascular barrier function would represent a significant advance in critical care medicine. We have previously reported the development of HPMA-based copolymers, targeted to endothelial glycocalyx that are able to enhance barrier function. In this work, we report the refinement of copolymer design and extend our physiological studies todemonstrate that the polymers: 1) reduce both shear stress and pressure-mediated increase in hydraulic conductivity, 2) reduce nitric oxide production in response to elevated hydrostatic pressure and, 3) reduce the capillary filtration coefficient (Kfc) in an isolated perfused mouse lung model. These copolymers represent an important tool for use in mechanotransduction research and a novel strategy for developing clinically useful copolymers for the treatment of vascular permeability. PMID:20932573

Conjugated Polymer Chains Confined in Vertical Nanocylinders of a Block-Copolymer Film: Preparation, Characterization, and Optoelectronic Function

KAUST Repository

Dong, Ban Xuan; Honmou, Yoshihiro; Komiyama, Hideaki; Furumaki, Shu; Iyoda, Tomokazu; Vacha, Martin

2013-01-01

Hybrid materials composed of phase-separated block copolymer films and conjugated polymers of the phenylenevinylene family (PPV) are prepared. The PPV chains are embedded in vertical cylinders of nanometer diameter in the block-copolymer films. The cylinders span continuously the whole film thickness of 70 nm. Incorporation of the PPV chains into the one-dimensional cylinders leads to modified photoluminescence spectra and to large absorption anisotropy. The hybrid films show electroluminescence from the PPV chains in a simple light-emitting device at minute doping concentrations, and also exhibit a factor of 19 increase in electron transport efficiency along the single PPV chains. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Conjugated Polymer Chains Confined in Vertical Nanocylinders of a Block-Copolymer Film: Preparation, Characterization, and Optoelectronic Function

KAUST Repository

Dong, Ban Xuan

2013-01-15

Hybrid materials composed of phase-separated block copolymer films and conjugated polymers of the phenylenevinylene family (PPV) are prepared. The PPV chains are embedded in vertical cylinders of nanometer diameter in the block-copolymer films. The cylinders span continuously the whole film thickness of 70 nm. Incorporation of the PPV chains into the one-dimensional cylinders leads to modified photoluminescence spectra and to large absorption anisotropy. The hybrid films show electroluminescence from the PPV chains in a simple light-emitting device at minute doping concentrations, and also exhibit a factor of 19 increase in electron transport efficiency along the single PPV chains. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

HPMA based macromolecular therapeutics: Internalization, intracellular pathway and cell death depend on the character of covalent bond between the drug and the peptidic spacer and also on spacer composition

Czech Academy of Sciences Publication Activity Database

Hovorka, Ondřej; Etrych, Tomáš; Šubr, Vladimír; Strohalm, Jiří; Ulbrich, Karel; Říhová, Blanka

2006-01-01

Roč. 14, č. 6 (2006), s. 391-403 ISSN 1061-186X R&D Projects: GA ČR GP305/04/P004; GA ČR GA305/05/2268; GA MŠk 1M0505 Institutional research plan: CEZ:AV0Z50200510; CEZ:AV0Z40500505 Keywords : hpma * intracellular transport * polymeric conjugates Subject RIV: EE - Microbiology, Virology Impact factor: 1.699, year: 2006

Air-stable π-conjugated amorphous copolymer field-effect transistors with high mobility of 0.3 cm²/Vs

DEFF Research Database (Denmark)

Georgakopoulos, S.; Gu, Y.; Nielsen, Martin Meedom

2012-01-01

We have fabricated organic bottom-contact top-gate field-effect transistors with an indenofluorene-phenanthrene co-polymer semiconductor, exhibiting ON/OFF ratio of 10(7) and uncommonly high mobility for an amorphous conjugated polymer of up to 0.3 cm(2)/Vs. Lack of crystallinity in this material...

Anti-lymphoma efficacy comparison of anti-Cd20 monoclonal antibody-targeted and non-targeted star-shaped polymer-prodrug conjugates

Czech Academy of Sciences Publication Activity Database

Lidický, Ondřej; Janoušková, Olga; Strohalm, Jiří; Alam, M.; Klener, P.; Etrych, Tomáš

2015-01-01

Roč. 20, č. 11 (2015), s. 19849-19864 ISSN 1420-3049 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0109; GA ČR(CZ) GA15-02986S; GA MŠk(CZ) LO1507 Institutional support: RVO:61389013 Keywords : HPMA copolymers * drug delivery systems * doxorubicin Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.465, year: 2015

High-molecular weight star conjugates containing docetaxel with high anti-tumor activity and low systemic toxicity in vivo

Czech Academy of Sciences Publication Activity Database

Etrych, Tomáš; Strohalm, Jiří; Šírová, Milada; Tomalová, Barbora; Rossmann, Pavel; Říhová, Blanka; Ulbrich, Karel; Kovář, Marek

2015-01-01

Roč. 6, č. 1 (2015), s. 160-170 ISSN 1759-9954 R&D Projects: GA ČR GAP301/11/0325; GA ČR GCP207/12/J030; GA MŠk(CZ) EE2.3.20.0055 Institutional support: RVO:61389013 ; RVO:61388971 Keywords : star polymer * HPMA copolymers * docetaxel Subject RIV: CD - Macromolecular Chemistry ; EC - Immunology (MBU-M) Impact factor: 5.687, year: 2015

Molecular architectures based on π-conjugated block copolymers for global quantum computation

International Nuclear Information System (INIS)

Mujica Martinez, C A; Arce, J C; Reina, J H; Thorwart, M

2009-01-01

We propose a molecular setup for the physical implementation of a barrier global quantum computation scheme based on the electron-doped π-conjugated copolymer architecture of nine blocks PPP-PDA-PPP-PA-(CCH-acene)-PA-PPP-PDA-PPP (where each block is an oligomer). The physical carriers of information are electrons coupled through the Coulomb interaction, and the building block of the computing architecture is composed by three adjacent qubit systems in a quasi-linear arrangement, each of them allowing qubit storage, but with the central qubit exhibiting a third accessible state of electronic energy far away from that of the qubits' transition energy. The third state is reached from one of the computational states by means of an on-resonance coherent laser field, and acts as a barrier mechanism for the direct control of qubit entanglement. Initial estimations of the spontaneous emission decay rates associated to the energy level structure allow us to compute a damping rate of order 10 -7 s, which suggest a not so strong coupling to the environment. Our results offer an all-optical, scalable, proposal for global quantum computing based on semiconducting π-conjugated polymers.

Molecular architectures based on pi-conjugated block copolymers for global quantum computation

Energy Technology Data Exchange (ETDEWEB)

Mujica Martinez, C A; Arce, J C [Universidad del Valle, Departamento de QuImica, A. A. 25360, Cali (Colombia); Reina, J H [Universidad del Valle, Departamento de Fisica, A. A. 25360, Cali (Colombia); Thorwart, M, E-mail: camujica@univalle.edu.c, E-mail: j.reina-estupinan@physics.ox.ac.u, E-mail: jularce@univalle.edu.c [Institut fuer Theoretische Physik IV, Heinrich-Heine-Universitaet Duesseldorf, 40225 Duesseldorf (Germany)

2009-05-01

We propose a molecular setup for the physical implementation of a barrier global quantum computation scheme based on the electron-doped pi-conjugated copolymer architecture of nine blocks PPP-PDA-PPP-PA-(CCH-acene)-PA-PPP-PDA-PPP (where each block is an oligomer). The physical carriers of information are electrons coupled through the Coulomb interaction, and the building block of the computing architecture is composed by three adjacent qubit systems in a quasi-linear arrangement, each of them allowing qubit storage, but with the central qubit exhibiting a third accessible state of electronic energy far away from that of the qubits' transition energy. The third state is reached from one of the computational states by means of an on-resonance coherent laser field, and acts as a barrier mechanism for the direct control of qubit entanglement. Initial estimations of the spontaneous emission decay rates associated to the energy level structure allow us to compute a damping rate of order 10{sup -7} s, which suggest a not so strong coupling to the environment. Our results offer an all-optical, scalable, proposal for global quantum computing based on semiconducting pi-conjugated polymers.

Simultaneous determination of mercapturic acids derived from ethylene oxide (HEMA), propylene oxide (2-HPMA), acrolein (3-HPMA), acrylamide (AAMA) and N,N-dimethylformamide (AMCC) in human urine using liquid chromatography/tandem mass spectrometry.

Science.gov (United States)

Schettgen, Thomas; Musiol, Anita; Kraus, Thomas

2008-09-01

Mercapturic acids are highly important and specific biomarkers of exposure to carcinogenic substances in occupational and environmental medicine. We have developed and validated a reliable, specific and very sensitive method for the simultaneous determination of five mercapturic acids derived from several high-production chemicals used in industry, namely ethylene oxide, propylene oxide, acrylamide, acrolein and N,N-dimethylformamide. Analytes are enriched and cleaned up from urinary matrix by offline solid-phase extraction. The mercapturic acids are subsequently separated by means of high-performance liquid chromatography on a Luna C8 (2) column and specifically quantified by tandem mass spectrometric detection using isotopically labelled analytes as internal standards. The limits of detection (LODs) for N-acetyl-S-2-carbamoylethylcysteine (AAMA) and N-acetyl-S-2-hydroxyethylcysteine (HEMA) were 2.5 microg/L and 0.5 microg/L urine, while for N-acetyl-S-3-hydroxypropylcysteine (3-HPMA), N-acetyl-S-2-hydroxypropylcysteine (2-HPMA) and N-acetyl-S-(N-methylcarbamoyl)cysteine (AMCC) it was 5 microg/L. These LODs were sufficient to detect the background exposure of the general population. We applied the method on spot urine samples of 28 subjects of the general population with no known occupational exposure to these substances. Median levels for AAMA, HEMA, 3-HPMA, 2-HPMA and AMCC in non-smokers (n = 14) were 52.6, 2.0, 155, 7.1 and 113.6 microg/L, respectively. In smokers (n = 14), median levels for AAMA, HEMA, 3-HPMA, 2-HPMA and AMCC were 243, 5.3, 1681, 41.7 and 822 microg/L, respectively. Due to the simultaneous quantification of these mercapturic acids, our method is well suited for the screening of workers with multiple chemical exposures as well as the determination of the background excretion of the general population.

HPMA copolymer-drug conjugates with controlled tumor-specific drug release

Czech Academy of Sciences Publication Activity Database

Chytil, Petr; Koziolová, Eva; Etrych, Tomáš; Ulbrich, Karel

2018-01-01

Roč. 18, č. 1 (2018), s. 1-15, č. článku 1700209. ISSN 1616-5187 R&D Projects: GA ČR(CZ) GA15-02986S; GA ČR(CZ) GA17-13283S; GA ČR(CZ) GA17-08084S; GA MŠk(CZ) LO1507 Institutional support: RVO:61389013 Keywords : biodegradable spacer * controlled drug release * drug delivery systems Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 3.238, year: 2016

Electrical characterization of fluorinated benzothiadiazole based conjugated copolymer – a promising material for high-performance solar cells

DEFF Research Database (Denmark)

Toušek, J.; Toušková, J.; Remeš, Z.

2015-01-01

Measurements of electrical conductivity, electron work function, carrier mobility ofholes and the diffusion length of excitons were performed on samples of conjugatedpolymers relevant to polymer solar cells. A state of the art fluorinated benzothiadiazolebased conjugated copolymer (PBDTTHD − DTBTff......) was studied and benchmarkedagainst the reference polymer poly-3-hexylthiophene (P3HT).We employed,respectively, four electrode conductivity measurements, Kelvin probe work functionmeasurements, carrier mobility using charge extraction by linearly increasing voltage(CELIV) measurements and diffusion length...

Determination of Urine 3-HPMA, a Stable Acrolein Metabolite in a Rat Model of Spinal Cord Injury

Science.gov (United States)

Zheng, Lingxing; Park, Jonghyuck; Walls, Michael; Tully, Melissa; Jannasch, Amber; Cooper, Bruce

2013-01-01

Abstract Acrolein has been suggested to be involved in a variety of pathological conditions. The monitoring of acrolein is of significant importance in delineating the pathogenesis of various diseases. Aimed at overcoming the reactivity and volatility of acrolein, we describe a specific and stable metabolite of acrolein in urine, N-acetyl-S-3-hydroxypropylcysteine (3-HPMA), as a potential surrogate marker for acrolein quantification. Using the LC/MS/MS method, we demonstrated that 3-HPMA was significantly elevated in a dose-dependent manner when acrolein was injected into rats IP or directly into the spinal cord, but not when acrolein scavengers were co-incubated with acrolein solution. A nonlinear mathematic relationship is established between acrolein injected directly into the spinal cord and a correlated dose-dependent increase of 3-HPMA, suggesting the increase of 3-HPMA becomes less apparent as the level of injected acrolein increases. The elevation of 3-HPMA was further detected in the rat spinal cord injury, a pathological condition known to be associated with elevated endogenous acrolein. This finding was further validated by concomitant confirmation of increased acrolein-lysine adducts using established dot immunoblotting techniques. The noninvasive nature of measuring 3-HPMA concentrations in urine allows for long-term monitoring of acrolein in the same animal and ultimately in human clinical studies. Due to wide spread involvement of acrolein in human health, the benefits of this study have the potential to enhance human health significantly. PMID:23697633

Structural and chemical aspects of HPMA copolymers as drug carriers

Czech Academy of Sciences Publication Activity Database

Ulbrich, Karel; Šubr, Vladimír

2010-01-01

Roč. 62, č. 17 (2010), s. 150-166 ISSN 0169-409X R&D Projects: GA AV ČR KAN200200651; GA AV ČR IAAX00500803 Institutional research plan: CEZ:AV0Z40500505 Keywords : drug-delivery systems * N-(2-hydroxypropyl)methacrylamide * polymer drug conjugates Subject RIV: CD - Macromolecular Chemistry Impact factor: 13.577, year: 2010

Quantum dot-polymer conjugates for stable luminescent displays.

Science.gov (United States)

Ghimire, Sushant; Sivadas, Anjaly; Yuyama, Ken-Ichi; Takano, Yuta; Francis, Raju; Biju, Vasudevanpillai

2018-05-23

The broad absorption of light in the UV-Vis-NIR region and the size-based tunable photoluminescence color of semiconductor quantum dots make these tiny crystals one of the most attractive antennae in solar cells and phosphors in electrooptical devices. One of the primary requirements for such real-world applications of quantum dots is their stable and uniform distribution in optically transparent matrices. In this work, we prepare transparent thin films of polymer-quantum dot conjugates, where CdSe/ZnS quantum dots are uniformly distributed at high densities in a chitosan-polystyrene copolymer (CS-g-PS) matrix. Here, quantum dots in an aqueous solution are conjugated to the copolymer by a phase transfer reaction. With the stable conjugation of quantum dots to the copolymer, we prevent undesired phase separation between the two and aggregation of quantum dots. Furthermore, the conjugate allows us to prepare transparent thin films in which quantum dots are uniformly distributed at high densities. The CS-g-PS copolymer helps us in not only preserving the photoluminescence properties of quantum dots in the film but also rendering excellent photostability to quantum dots at the ensemble and single particle levels, making the conjugate a promising material for photoluminescence-based devices.

Effect of side chain position on solar cell performance in cyclopentadithiophene-based copolymers

International Nuclear Information System (INIS)

Lee, Sang Kyu; Seo, Jung Hwa; Cho, Nam Sung; Cho, Shinuk

2012-01-01

The photovoltaic properties of a series of low band-gap conjugated copolymers, in which alkyl side chains were substituted at various positions, were investigated using donor–acceptor (D–A) conjugated copolymers consisting of a cyclopentadithiophene derivative and dithienyl-benzothiadiazole. The base polymer, which has no alkyl side chains, yielded promising power conversion efficiency of 3.8%. Polymers with alkyl side chains, however, exhibited significantly decreased performance. In addition, the effects of processing additive became negligible. The results indicate that substituted side chains, which were introduced to improve solubility, critically affected the optical and electronic properties of D–A conjugated copolymers. Furthermore, the position of the side chain was also very important for controlling the morphological properties of the D–A conjugated copolymers. - Highlights: ► Effect of side chain position on solar cell performance was investigated. ► Polymer without alkyl chains yielded promising power conversion efficiency of 3.8%. ► Position of side chains critically affected the optical and electronic properties.

Interplay of alternative conjugated pathways and steric interactions on the electronic and optical properties of donor-acceptor conjugated polymers

KAUST Repository

Lima, Igo T.; Risko, Chad; Aziz, Saadullah Gary; Da Silva Filho, Demé trio A Da Silva; Bredas, Jean-Luc

2014-01-01

Donor-acceptor π-conjugated copolymers are of interest for a wide range of electronic applications, including field-effect transistors and solar cells. Here, we present a density functional theory (DFT) study of the impact of varying the conjugation pathway on the geometric, electronic, and optical properties of donor-acceptor systems. We consider both linear ("in series"), traditional conjugation among the donor-acceptor moieties versus structures where the acceptor units are appended orthogonally to the linear, donor-only conjugated backbone. Long-range-corrected hybrid functionals are used in the investigation with the values of the tuned long-range separation parameters providing an estimate of the extent of conjugation as a function of the oligomer architecture. Considerable differences in the electronic and optical properties are determined as a function of the nature of the conjugation pathway, features that should be taken into account in the design of donor-acceptor copolymers.

Polymer conjugates of doxorubicin bound through an amide and hydrazone bond: impact of the carrier structure onto synergistic action in the treatment of solid tumours

Czech Academy of Sciences Publication Activity Database

Etrych, Tomáš; Šubr, Vladimír; Laga, Richard; Říhová, Blanka; Ulbrich, Karel

2014-01-01

Roč. 58, 16 July (2014), s. 1-12 ISSN 0928-0987 R&D Projects: GA ČR GAP301/11/0325; GA MŠk EE2.3.30.0029; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61389013 ; RVO:61388971 Keywords : HPMA copolymer * synergistic effect * doxorubicin Subject RIV: CE - Biochemistry; FD - Oncology ; Hematology (MBU-M) Impact factor: 3.350, year: 2014

Dual fluorescent N-(2-hydroxypropyl) methacrylamide-based conjugates for passive tumor targeting with reduction-sensitive drug release: proof of the concept, tumor accumulation, and biodistribution

Czech Academy of Sciences Publication Activity Database

Studenovský, Martin; Heinrich, A. K.; Lucas, H.; Mueller, T.; Mäder, K.; Etrych, Tomáš

2016-01-01

Roč. 31, č. 4 (2016), s. 348-360 ISSN 0883-9115 R&D Projects: GA ČR(CZ) GCP207/12/J030; GA ČR(CZ) GA14-12742S; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61389013 Keywords : HPMA copolymers * reduction-responsive drug release * tumor accumulation Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.310, year: 2016

Styrene-maleic acid-copolymer conjugated zinc protoporphyrin as a candidate drug for tumor-targeted therapy and imaging.

Science.gov (United States)

Fang, Jun; Tsukigawa, Kenji; Liao, Long; Yin, Hongzhuan; Eguchi, Kanami; Maeda, Hiroshi

2016-01-01

Previous studies indicated the potential of zinc protoporphyrin (ZnPP) as an antitumor agent targeting to the tumor survival factor heme oxygenase-1, and/or for photodynamic therapy (PDT). In this study, to achieve tumor-targeted delivery, styrene-maleic acid-copolymer conjugated ZnPP (SMA-ZnPP) was synthesized via amide bond, which showed good water solubility, having ZnPP loading of 15%. More importantly, it forms micelles in aqueous solution with a mean particle size of 111.6 nm, whereas it has an apparent Mw of 65 kDa. This micelle formation was not detracted by serum albumin, suggesting it is stable in circulation. Further SMA-ZnPP conjugate will behave as an albumin complex in blood with much larger size (235 kDa) by virtue of the albumin binding property of SMA. Consequently, SMA-ZnPP conjugate exhibited prolonged circulating retention and preferential tumor accumulation by taking advantage of enhanced permeability and retention (EPR) effect. Clear tumor imaging was thus achieved by detecting the fluorescence of ZnPP. In addition, the cytotoxicity and PDT effect of SMA-ZnPP conjugate was confirmed in human cervical cancer HeLa cells. Light irradiation remarkably increased the cytotoxicity (IC50, from 33 to 5 μM). These findings may provide new options and knowledge for developing ZnPP based anticancer theranostic drugs.

Co-crystallization phase transformations in all π-conjugated block copolymers with different main-chain moieties.

Science.gov (United States)

Lee, Yi-Huan; Chen, Wei-Chih; Yang, Yi-Lung; Chiang, Chi-Ju; Yokozawa, Tsutomu; Dai, Chi-An

2014-05-21

Driven by molecular affinity and balance in the crystallization kinetics, the ability to co-crystallize dissimilar yet self-crystallizable blocks of a block copolymer (BCP) into a uniform domain may strongly affect its phase diagram. In this study, we synthesize a new series of crystalline and monodisperse all-π-conjugated poly(2,5-dihexyloxy-p-phenylene)-b-poly(3-(2-ethylhexyl)thiophene) (PPP-P3EHT) BCPs and investigate this multi-crystallization effect. Despite vastly different side-chain and main-chain structures, PPP and P3EHT blocks are able to co-crystallize into a single uniform domain comprising PPP and P3EHT main-chains with mutually interdigitated side-chains spaced in-between. With increasing P3EHT fraction, PPP-P3EHTs undergo sequential phase transitions and form hierarchical superstructures including predominately PPP nanofibrils, co-crystalline nanofibrils, a bilayer co-crystalline/pure P3EHT lamellar structure, a microphase-separated bilayer PPP-P3EHT lamellar structure, and finally P3EHT nanofibrils. In particular, the presence of the new co-crystalline lamellar structure is the manifestation of the interaction balance between self-crystallization and co-crystallization of the dissimilar polymers on the resulting nanostructure of the BCP. The current study demonstrates the co-crystallization nature of all-conjugated BCPs with different main-chain moieties and may provide new guidelines for the organization of π-conjugated BCPs for future optoelectronic applications.

Preparation of Fe3 O4 @ion imprinted poly(MMA-HPMA-DVB)magnetic composite and its selective adsorption to Ni(Ⅱ)%磁性Fe3O4@离子印迹聚(MMA-HPMA-DVB)复合材料的合成及其对水中Ni(Ⅱ)选择性吸附

Institute of Scientific and Technical Information of China (English)

王燕; 叶思; 吕珊珊; 张佳丽; 沈昊宇; 叶仙森

2017-01-01

采用超声协助悬浮聚合法以Ni(Ⅱ)离子为模板制备了氨基功能化纳米Fe3O4-离子印迹聚(甲基丙烯酸甲酯(MMA)-3-(2-氨基乙基胺)-2-甲基丙烯酸羟丙酯(HPMA)-二乙烯基苯(DVB))磁性复合材料(Fe3O4@ion im-printed poly(MMA-HPMA-DVB),Fe3 O4@IIP(MMA-HPMA-DVB)).通过EA、XRD、FTIR、TEM、VSM等手段对Fe3O4@IIP(MMA-HPMA-DVB)的组成、结构、形貌、磁性等进行了表征,并研究了其吸附水中Ni(Ⅱ)的性能.结果表明:合成的Fe3O4@IIP(MMA-HPMA-DVB)平均粒径为100 nm,饱和磁化强度为43.8 emu/g;共聚单体甲基丙烯酸甲酯(MMA)的羰基通过氢键与Fe3O4表面羟基结合,有利于Fe3O4@IIP(MMA-HPMA-DVB)的核-壳结构的形成与稳定;Fe3O4@IIP(MMA-HPMA-DVB)对Ni(Ⅱ)的吸附受溶液pH值影响较小;等温吸附线符合Langmuir模型,饱和吸附量(q m,c=500 mg/g,q m,e=478 mg/g)高于非离子印迹材料(Fe3 O4@none-ion imprinted poly(MMA-HPMA-DVB),Fe3 O4@NIP(MMA-HPMA-DVB)),q m,c=90.9 mg/g,q m,e=83.8 mg/g).吸附过程可在5 min内达到平衡,符合准二级动力学模型.Fe3 O4@IIP(MMA-HPMA-DVB)能高选择性地有效吸附水中Ni(Ⅱ),对Ni(Ⅱ)的印迹因子(α)为1.9,对几种常见共存离子的选择性因子(β)>7.7,是潜在的高选择性吸附和回收Ni(Ⅱ)的功能材料.%An amino-functionalized Fe3 O4-ion imprinted poly(methyl methacrylate (MMA)-3-(2-amino-ethylami-no)-2-hydroxypropyl methacrylate (HPMA)-divinylbenzene(DVB))magnetic composite (Fe3 O4 @ion imprinted po-ly(IIP)(MMA-HPMA-DVB))was synthesized via ultrasonic assisted suspension polymerization with nickel(Ⅱ)as ion imprinting template.The Fe3 O4 @IIP(MMA-HPMA-DVB)was characterized by EA,XRD,FTIR,TEM,TG and VSM.The application for its adsorption properties on Ni(Ⅱ)from water was investigated.The results show that the Fe3 O4 @IIP(MMA-HPMA-DVB)has an average size of 100 nm,with the saturation magnetization intensity of 43.8 emu/g.The carbonyl group of the co-monomer methyl methacrylate (MMA)can connect

Amphiphilic block copolymers for biomedical applications

Science.gov (United States)

Zupancich, John Andrew

Amphiphilic block copolymer self-assembly provides a versatile means to prepare nanoscale objects in solution. Control over aggregate shape is granted through manipulation of amphiphile composition and the synthesis of well-defined polymers offers the potential to produce micelles with geometries optimized for specific applications. Currently, polymer micelles are being investigated as vehicles for the delivery of therapeutics and attempts to increase efficacy has motivated efforts to incorporate bioactive ligands and stimuli-responsive character into these structures. This thesis reports the synthesis and self-assembly of biocompatible, degradable polymeric amphiphiles. Spherical, cylindrical, and bilayered vesicle structures were generated spontaneously by the direct dispersion of poly(ethylene oxide)-b-poly(gamma-methyl-ε-caprolactone) block copolymers in water and solutions were characterized with cryogenic transmission electron microscopy (cryo-TEM). The dependence of micelle structure on diblock copolymer composition was examined through the systematic variation of the hydrophobic block molecular weight. A continuous evolution of morphology was observed with coexistence of aggregate structures occurring in windows of composition intermediate to that of pure spheres, cylinders and vesicles. A number of heterobifunctional poly(ethylene oxide) polymers were synthesized for the preparation of ligand-functionalized amphiphilic diblock copolymers. The effect of ligand conjugation on block copolymer self-assembly and micelle morphology was also examined. An RGD-containing peptide sequence was efficiently conjugated to a set of well characterized poly(ethylene oxide)-b-poly(butadiene) copolymers. The reported aggregate morphologies of peptide-functionalized polymeric amphiphiles deviated from canonical structures and the micelle clustering, cylinder fragmentation, network formation, and multilayer vesicle generation documented with cryo-TEM was attributed to

Dual fluorescent HPMA copolymers for passive tumor targeting with pH-sensitive drug release: synthesis and characterization of distribution and tumor accumulation in mice by noninvasive multispectral optical imaging

Czech Academy of Sciences Publication Activity Database

Hoffmann, S.; Vystrčilová, Lucie; Ulbrich, Karel; Etrych, Tomáš; Caysa, H.; Mueller, T.; Mäder, K.

2012-01-01

Roč. 13, č. 3 (2012), s. 652-663 ISSN 1525-7797 R&D Projects: GA AV ČR IAAX00500803; GA ČR GAP301/11/0325 Institutional research plan: CEZ:AV0Z40500505 Keywords : fluorescence dyes * star -like HPMA polymer carriers * diagnostics of tumors Subject RIV: EC - Immunology Impact factor: 5.371, year: 2012

Determination of Urine 3-HPMA, a Stable Acrolein Metabolite in a Rat Model of Spinal Cord Injury

OpenAIRE

Zheng, Lingxing; Park, Jonghyuck; Walls, Michael; Tully, Melissa; Jannasch, Amber; Cooper, Bruce; Shi, Riyi

2013-01-01

Acrolein has been suggested to be involved in a variety of pathological conditions. The monitoring of acrolein is of significant importance in delineating the pathogenesis of various diseases. Aimed at overcoming the reactivity and volatility of acrolein, we describe a specific and stable metabolite of acrolein in urine, N-acetyl-S-3-hydroxypropylcysteine (3-HPMA), as a potential surrogate marker for acrolein quantification. Using the LC/MS/MS method, we demonstrated that 3-HPMA was significa...

Facile Synthesis of Well-Defined MDMO-PPV Containing (TriBlock—Copolymers via Controlled Radical Polymerization and CuAAC Conjugation

Directory of Open Access Journals (Sweden)

Neomy Zaquen

2015-02-01

Full Text Available A systematic investigation into the chain transfer polymerization of the so-called radical precursor polymerization of poly(p-phenylene vinylene (PPV materials is presented. Polymerizations are characterized by systematic variation of chain transfer agent (CTA concentration and reaction temperature. For the chain transfer constant, a negative activation energy of −12.8 kJ·mol−1 was deduced. Good control over molecular weight is achieved for both the sulfinyl and the dithiocarbamate route (DTC. PPVs with molecular weights ranging from thousands to ten thousands g·mol−1 were obtained. To allow for a meaningful analysis of the CTA influence, Mark–Houwink–Kuhn–Sakurada (MHKS parameters were determined for conjugated MDMO-PPV ([2-methoxy-5-(3',7'-dimethyloctyloxy]-1,4-phenylenevinylene to α = 0.809 and k = 0.00002 mL·g−1. Further, high-endgroup fidelity of the CBr4-derived PPVs was proven via chain extension experiments. MDMO-PPV-Br was successfully used as macroinitiator in atom transfer radical polymerization (ATRP with acrylates and styrene. A more polar PPV counterpart was chain extended by an acrylate in single-electron transfer living radical polymerization (SET-LRP. In a last step, copper-catalyzed azide alkyne cycloaddition (CuAAC was used to synthesize block copolymer structures. Direct azidation followed by macromolecular conjugation showed only partial success, while the successive chain extension via ATRP followed by CuAAC afforded triblock copolymers of the poly(p-phenylene vinylene-block-poly(tert-butyl acrylate-block-poly(ethylene glycol (PPV-b-PtBuA-b-PEG.

Theory of Primary Photoexcitations in Donor-Acceptor Copolymers

OpenAIRE

Aryanpour, Karan; Dutta, Tirthankar; Huynh, Uyen N. V.; Vardeny, Zeev Valy; Mazumdar, Sumit

2015-01-01

We present a generic theory of primary photoexcitations in low band gap donor-acceptor conjugated copolymers. Because of the combined effects of strong electron correlations and broken symmetry, there is considerable mixing between a charge-transfer exciton and an energetically proximate triplet-triplet state with an overall spin singlet. The triplet-triplet state, optically forbidden in homopolymers, is allowed in donor-acceptor copolymers. For an intermediate difference in electron affiniti...

Non-covalent functionalization of carbon nanotubes: Controlling Chirality Selectivity via Alkyl Groups of Conjugated Co-Polymers

Science.gov (United States)

Weight, Braden; Gifford, Brendan; Kilina, Svetlana

Carbon nanotubes (CNTs) play an important role in nanotechnology, including electronics, chemical sensors, and solar cells. Their electronic and optical properties depend on the size and geometry (chirality) of the nanotube. However, one main concern regarding nanotube application in optoelectronic devices is the difficulty of separating them based upon chirality after synthesis, as all known synthesis methods produce more than one chirality simultaneously. To get around this, one method is the functionalization of the CNTs via non-covalent bonding of co-polymers by wrapping them around the tube. We use force field simulations to explore the effects of various structural manipulations to the co-polymer 9,9-dialkylfluorenyl-2,7-diyl bipyridine (PFO-BPY) to find the preferential mechanisms of selective interactions between the PFO-BPY and CNTs of various chiralities. In particular, we focus on the effect of the branching in alkyl side-groups of PFO-BPY on their binding to the CNT surface. We have observed correlations between the side-group structures and their wrapping morphology on the CNT-Polymer interactions. Our calculations demonstrate that the branching in the position closest to the conjugated backboned results in the strongest interaction with all CNT. This research was supported by the National Science Foundation (CHE 1413614) and the Center for Computationally-Assisted Science and Technology at NDSU.

An Inter-Laboratory Comparison for the Urinary Acrolein Biomarker 3-Hydroxypropyl-Mercapturic Acid (3-HPMA

Directory of Open Access Journals (Sweden)

Scherer Gerhard

2017-01-01

Full Text Available An inter-laboratory comparison study on the acrolein biomarker of exposure 3-hydroxypropyl-mercapturic acid (3-HPMA with 12 laboratories from 7 globally distributed countries was performed. The laboratories received coded triplicates of 4 spiked and lyophilized urine samples (LU, 12 samples as well as 5 authentic urine pool samples (PU, 15 samples covering the 3-HPMA concentration range from background (non-smoking to heavy smoking levels for analysis by using their own (in-house analytical method. All laboratories applied liquid chromatography with tandem mass spectrometry (LC-MS/MS, with most of them (10 of 12 using solid phase extraction (SPE as sample work-up procedure. The intra-laboratory variation (indicating repeatability was determined by calculating the standard deviation (sr and the coefficient of variation (CVr of the triplicates, whereas the inter-laboratory variation (indicating reproducibility was determined by calculating the standard deviation between laboratories (sR and the corresponding coefficient of variation (CVR. After removal of outlier samples or laboratories, the mean CVr values for LU and PU test samples ranged from 2.1–3.6% (mean: 2.8% and 2.4–3.7% (mean: 3.3%, respectively, indicating good repeatability for the determination of 3-HPMA in both sample types. CVR for LU and PU test samples ranged from 9.1–31.9% (mean: 18.8% and 13.9–27.0% (mean: 18.5%, respectively, indicating limited reproducibility in 3-HPMA analysis for both sample types. Re-calculation of the PU results by applying an embedded calibration (EC, derived from the reported peak areas for the LU test samples, somewhat improved the CVR values (range: 9.6–28.8%, mean: 16.7%.

Spectral Signatures of Polarons in Conjugated Co-polymers

NARCIS (Netherlands)

Wiebeler, Christian; Tautz, Raphael; Feldmann, Jochen; von Hauff, Elizabeth; Da Como, Enrico; Schumacher, Stefan

2013-01-01

We study electronic and optical properties of the low-bandgap co-polymer PCPDT-BT (poly-cyclopentadithiophene-co-benzothiadiazole) and compare it with the corresponding homo-polymer PCPDT (poly-cyclopentadithiophene). We investigate the linear absorptivity in these systems for neutral molecules and

G3-C12 Peptide Reverses Galectin-3 from Foe to Friend for Active Targeting Cancer Treatment.

Science.gov (United States)

Sun, Wei; Li, Lian; Yang, Qingqing; Shan, Wei; Zhang, Zhirong; Huang, Yuan

2015-11-02

Galectin-3 is overexpressed by numerous carcinomas and is a potential target for active tumor treatments. On the other hand, galectin-3 also plays a key role in cancer progression and prevents cells from undergoing apoptosis, thereby offsetting the benefits of active targeting drugs. However, the relative contribution of the protective antiapoptotic effects of galectin-3 and the proapoptotic effects of galectin-3-targeted therapies has remained yet unrevealed. Here, we show that a galectin-3-binding peptide G3-C12 could reverse galectin-3 from foe to friend for active targeting delivery system. Results showed G3-C12 modified N-(2-hydroxypropyl)methacrylamide copolymer doxorubicin conjugates (G3-C12-HPMA-Dox) could internalize into galectin-3 overexpressed PC-3 cells via a highly specific ligand-receptor pathway (2.2 times higher cellular internalization than HPMA-Dox). The internalized Dox stimulated the translocation of galectin-3 to the mitochondria to prevent from apoptosis. In turn, this caused G3-C12-HPMA-Dox to concentrate into the mitochondria after binding to galectin-3 intracellularly. Initially, mitochondrial galectin-3 weakened Dox-induced mitochondrial damage; however, as time progressed, G3-C12 active-mediation allowed increasing amounts of Dox to be delivered to the mitochondria, which eventually induced higher level of apoptosis than nontargeted copolymers. In addition, G3-C12 downregulates galectin-3 expression, 0.43 times lower than control cells, which could possibly be responsible for the suppressed cell migration. Thus, G3-C12 peptide exerts sequential targeting to both cell membrane and mitochondria via regulating galectin-3, and eventually reverses and overcomes the protective effects of galectin-3; therefore, it could be a promising agent for the treatment of galectin-3-overexpressing cancers.

Uniform two-dimensional square assemblies from conjugated block copolymers driven by π–π interactions with controllable sizes

Energy Technology Data Exchange (ETDEWEB)

Han, Liang; Wang, Meijing; Jia, Xiangmeng; Chen, Wei; Qian, Hujun; He, Feng

2018-02-28

Two-dimensional (2-D) micro- and nano- architectures are attractive because of their unique properties caused by their ultrathin and flat morphologies. However, the formation of 2-D supramolecular highly symmetrical structures with considerable control is still a major challenge. Here, we presented a simple approach for the preparation of regular and homogeneous 2-D fluorescent square noncrystallization micelles with conjugated diblock copolymers PPV12-b-P2VPn through a process of dissolving-cooling-aging. The scale of the formed micelles could be controlled by the ratio of PPV/P2VP blocks and the concentration of the solution. The forming process of the platelet square micelles was analyzed by UV-Vis, DLS and SLS, while the molecular arrangement was characterized by GIXD. The results revealed that the micelles of PPV12-b-P2VPn initially form 1-D structures and then grow into 2-D structures in solution, and the growth is driven by intermolecular π-π interactions with the PPV12 blocks. The formation of 2-D square micelles is induced by herringbone arrangement of the molecules, which is closely related to the presence of the branched alkyl chains attached to conjugated PPV12 cores.

Infrared and ultraviolet spectroscopic studies of low-temperature radiolysis of ethylene - styrene copolymers

International Nuclear Information System (INIS)

Mal'tseva, A.P.; Golikov, V.P.; Leshchenko, S.S.; Karpov, V.L.

1977-01-01

Certain features of low-temperature radiolysis of statistic ethylene-styrene copolymers have been studied by infrared and ultraviolet spectroscopy. It is shown that the nature of the accumulation and decay of trans-vinylene, vinyl and vinylidene double bonds in an ethylene-styrene copolymer is essentially influenced by both the dose absorbed and copolymer composition. A suggestion is made that the ethylene-styrene copolymer is formed when structures are irradiated containing double bonds conjugated with the phenyl rings of styrene groups - which more effectively dissipate the absorbed energy than solitary phenyl rings

Opto-electronic devices from block copolymers and their oligomers.

NARCIS (Netherlands)

Hadziioannou, G

1997-01-01

This paper presents research activities towards the development of polymer materials and devices for optoelectronics, An approach to controlling the conjugation length and transferring the luminescence properties of organic molecules to polymers through black copolymers containing well-defined

Hyperbranched–dendrimer architectural copolymer gene delivery using hyperbranched PEI conjugated to poly(propyleneimine) dendrimers: synthesis, characterization, and evaluation of transfection efficiency

Energy Technology Data Exchange (ETDEWEB)

Alavi, Seyyed Jamal [Ferdowsi University of Mashhad, Department of Chemistry, Faculty of Science (Iran, Islamic Republic of); Gholami, Leila [Mashhad University of Medical Sciences, Department of Modern Sciences and Technologies, School of Medicine (Iran, Islamic Republic of); Askarian, Saeedeh [Mashhad University of Medical Sciences, Department of Medical Biotechnology, School of Medicine (Iran, Islamic Republic of); Darroudi, Majid [Mashhad University of Medical Sciences, Nuclear Medicine Research Center (Iran, Islamic Republic of); Massoudi, Abdolhossein [University of Payam noor, Department of Chemistry (Iran, Islamic Republic of); Rezaee, Mehdi; Kazemi Oskuee, Reza, E-mail: Oskueekr@mums.ac.ir [Mashhad University of Medical Sciences, Department of Medical Biotechnology, School of Medicine (Iran, Islamic Republic of)

2017-02-15

The applications of dendrimer-based vectors seem to be promising in non-viral gene delivery because of their potential for addressing the problems with viral vectors. In this study, generation 3 poly(propyleneimine) (G3-PPI) dendrimers with 1, 4-diaminobutane as a core initiator was synthesized using a divergent growth approach. To increase the hydrophobicity and reduce toxicity, 10% of primary amines of G3-PPI dendrimers were replaced with bromoalkylcarboxylates with different chain lengths (6-bromohexanoic and 10-bromodecanoic). Then, to retain the overall buffering capacity and enhance transfection, the alkylcarboxylate–PPIs were conjugated to 10 kDa branched polyethylenimine (PEI). The results showed that the modified PPI was able to form complexes with the diameter of less than 60 nm with net-positive surface charge around 20 mV. No significant toxicity was observed in modified PPIs; however, the hexanoate conjugated PPI–PEI (PPI-HEX-10% PEI) and the decanoate conjugated PPI–PEI (PPI-DEC-10%-PEI) showed the best transfection efficiency in murine neuroblastoma (Neuro-2a) cell line, even PPI-HEX-10%-PEI showed transfection efficiency equal to standard PEI 25 kDa with reduced toxicity. This study suggested a new series of hyperbranched (PEI)–dendrimer (PPI) architectural copolymers as non-viral gene delivery vectors with high transfection efficiency and low toxicity.

Hyperbranched-dendrimer architectural copolymer gene delivery using hyperbranched PEI conjugated to poly(propyleneimine) dendrimers: synthesis, characterization, and evaluation of transfection efficiency

Science.gov (United States)

Alavi, Seyyed Jamal; Gholami, Leila; Askarian, Saeedeh; Darroudi, Majid; Massoudi, Abdolhossein; Rezaee, Mehdi; Kazemi Oskuee, Reza

2017-02-01

The applications of dendrimer-based vectors seem to be promising in non-viral gene delivery because of their potential for addressing the problems with viral vectors. In this study, generation 3 poly(propyleneimine) (G3-PPI) dendrimers with 1, 4-diaminobutane as a core initiator was synthesized using a divergent growth approach. To increase the hydrophobicity and reduce toxicity, 10% of primary amines of G3-PPI dendrimers were replaced with bromoalkylcarboxylates with different chain lengths (6-bromohexanoic and 10-bromodecanoic). Then, to retain the overall buffering capacity and enhance transfection, the alkylcarboxylate-PPIs were conjugated to 10 kDa branched polyethylenimine (PEI). The results showed that the modified PPI was able to form complexes with the diameter of less than 60 nm with net-positive surface charge around 20 mV. No significant toxicity was observed in modified PPIs; however, the hexanoate conjugated PPI-PEI (PPI-HEX-10% PEI) and the decanoate conjugated PPI-PEI (PPI-DEC-10%-PEI) showed the best transfection efficiency in murine neuroblastoma (Neuro-2a) cell line, even PPI-HEX-10%-PEI showed transfection efficiency equal to standard PEI 25 kDa with reduced toxicity. This study suggested a new series of hyperbranched (PEI)-dendrimer (PPI) architectural copolymers as non-viral gene delivery vectors with high transfection efficiency and low toxicity.

Conjugates of Superoxide Dismutase 1 with Amphiphilic Poly(2-oxazoline) Block Copolymers for Enhanced Brain Delivery: Synthesis, Characterization and Evaluation in Vitro and in Vivo

KAUST Repository

Tong, Jing

2013-01-07

Superoxide dismutase 1 (SOD1) efficiently catalyzes dismutation of superoxide, but its poor delivery to the target sites in the body, such as brain, hinders its use as a therapeutic agent for superoxide-associated disorders. Here to enhance the delivery of SOD1 across the blood-brain barrier (BBB) and in neurons the enzyme was conjugated with poly(2-oxazoline) (POx) block copolymers, P(MeOx-b-BuOx) or P(EtOx-b-BuOx), composed of (1) hydrophilic 2-methyl-2-oxazoline (MeOx) or 2-ethyl-2-oxazoline (EtOx) and (2) hydrophobic 2-butyl-2-oxazoline (BuOx) repeating units. The conjugates contained from 2 to 3 POx chains joining the protein amino groups via cleavable -(ss)- or noncleavable -(cc)- linkers at the BuOx block terminus. They retained 30% to 50% of initial SOD1 activity, were conformationally and thermally stable, and assembled in 8 or 20 nm aggregates in aqueous solution. They had little if any toxicity to CATH.a neurons and displayed enhanced uptake in these neurons as compared to native or PEGylated SOD1. Of the two conjugates, SOD1-(cc)-P(MeOx-b-BuOx) and SOD1-(cc)-P(EtOx-b-BuOx), compared, the latter was entering cells 4 to 7 times faster and at 6 h colocalized predominantly with endoplasmic reticulum (41 ± 3%) and mitochondria (21 ± 2%). Colocalization with endocytosis markers and pathway inhibition assays suggested that it was internalized through lipid raft/caveolae, also employed by the P(EtOx-b-BuOx) copolymer. The SOD activity in cell lysates and ability to attenuate angiotensin II (Ang II)-induced superoxide in live cells were increased for this conjugate compared to SOD1 and PEG-SOD1. Studies in mice showed that SOD1-POx had ca. 1.75 times longer half-life in blood than native SOD1 (28.4 vs 15.9 min) and after iv administration penetrated the BBB significantly faster than albumin to accumulate in brain parenchyma. The conjugate maintained high stability both in serum and in brain (77% vs 84% at 1 h postinjection). Its amount taken up by the brain

Morphology and electrical properties of electrochemically synthesized pyrrole–formyl pyrrole copolymer

Energy Technology Data Exchange (ETDEWEB)

Gholami, Mehrdad, E-mail: mehrdad897@um.edu.my [Department of Chemistry, University of Malaya, Kuala Lumpur 50603 (Malaysia); Department of Chemistry, Marvdasht Branch, Islamic Azad University, P.O. Box 465, Marvdasht (Iran, Islamic Republic of); Nia, Pooria Moozarm, E-mail: pooriamn@yahoo.com [Department of Chemistry, University of Malaya, Kuala Lumpur 50603 (Malaysia); Alias, Yatimah, E-mail: yatimah70@um.edu.my [Department of Chemistry, University of Malaya, Kuala Lumpur 50603 (Malaysia)

2015-12-01

Graphical abstract: - Highlights: • The (Py–co-FPy) copolymer was synthesized electrochemically. • This copolymer has 1.6 times higher surface coverage compared to polypyrrole. • This copolymer showed 2.5 times lower resistance compared to polypyrrole. • The conjugated structure between Py and FPy causes enhancement of conductivity. • This conducting copolymer has a strong potential to be used in various applications. - Abstract: A direct electrochemical copolymerization of pyrrole–formyl pyrrole (Py–co-FPy) was carried out by oxidative copolymerization of formyl pyrrole and pyrrole in LiClO{sub 4} aqueous solution through galvanostatic method. The (Py–co-FPy) copolymer was characterized using Fourier-transform infrared spectroscopy (FT-IR), field emission scanning electron microscope (FESEM), energy-filtering transmission electron microscope (EFTEM), thermal gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The FESEM images showed that the synthesized copolymer had a hollow whelk-like helixes structure, which justifies the enhancement of charge transportation through the copolymer film. Cyclic voltammetry studies revealed that the electrocatalytic activity of synthesized copolymer has improved and the surface coverage in copolymer enhanced 1.6 times compared to polypyrrole alone. Besides, (Py–co-FPy) copolymer showed 2.5 times lower electrochemical charge transfer resistance (R{sub ct}) value in impedance spectroscopy. Therefore, this copolymer has a strong potential to be used in several applications such as sensor applications.

Molecular designing of novel ternary copolymers of donor-acceptor polymers using genetic algorithm

International Nuclear Information System (INIS)

Arora, Vinita; Bakhshi, A.K.

2010-01-01

Graphical abstract: Alternate arrangement of donor acceptor moieties in the carbon backbone chain of an organic conjugated polymer is capable of inducing charge transfer and affects the electronic properties of the copolymer. Genetic algorithm along with simple NFC (negative factor counting) and IIM (inverse iteration method) has been used to optimize the properties of novel ternary copolymers based on polypyrrole PPy, polythiophene PTh and polyfuran PFu (as donor moieties) and containing >C=O and >C=CF 2 bridging units as acceptor moieties. - Abstract: An efficient designing route to novel ternary copolymers consisting of polypyrrole (PPy), polythiophene (PTh) and polyfuran (PFu) is developed with the help of genetic algorithm. Using the band structure results obtained from ab initio crystal orbital (CO) calculations, the electronic structures and conduction properties of real ternary copolymers based on donor acceptor type polymers are investigated. The electron rich heterocyclic rings in the backbone chain of the copolymer are joined together by electron withdrawing groups Y, carbonyl group (>C=O) and difluoromethylene group (>C=CF 2 ) in an attempt to design the conducting polymer with lowest band gap. A comparative study of various electronic properties is presented. The effects of substitution on the behaviour and properties of the copolymers as well as on the density of states (DOS) are discussed. Band gap decreases as a result of substitution on the polymer backbone chain due to decrease in ionization potential and increase in electron affinity values. This is expected to enhance the intrinsic conductivity of the resulting copolymer. Use of alternate donor acceptor moieties within the repeat units should maximize the extended π conjugation.

Molecular designing of novel ternary copolymers of donor-acceptor polymers using genetic algorithm

Energy Technology Data Exchange (ETDEWEB)

Arora, Vinita [Department of Chemistry, University of Delhi, Delhi 110 007 (India); Bakhshi, A.K., E-mail: akbakhshi2000@yahoo.com [Department of Chemistry, University of Delhi, Delhi 110 007 (India)

2010-08-03

Graphical abstract: Alternate arrangement of donor acceptor moieties in the carbon backbone chain of an organic conjugated polymer is capable of inducing charge transfer and affects the electronic properties of the copolymer. Genetic algorithm along with simple NFC (negative factor counting) and IIM (inverse iteration method) has been used to optimize the properties of novel ternary copolymers based on polypyrrole PPy, polythiophene PTh and polyfuran PFu (as donor moieties) and containing >C=O and >C=CF{sub 2} bridging units as acceptor moieties. - Abstract: An efficient designing route to novel ternary copolymers consisting of polypyrrole (PPy), polythiophene (PTh) and polyfuran (PFu) is developed with the help of genetic algorithm. Using the band structure results obtained from ab initio crystal orbital (CO) calculations, the electronic structures and conduction properties of real ternary copolymers based on donor acceptor type polymers are investigated. The electron rich heterocyclic rings in the backbone chain of the copolymer are joined together by electron withdrawing groups Y, carbonyl group (>C=O) and difluoromethylene group (>C=CF{sub 2}) in an attempt to design the conducting polymer with lowest band gap. A comparative study of various electronic properties is presented. The effects of substitution on the behaviour and properties of the copolymers as well as on the density of states (DOS) are discussed. Band gap decreases as a result of substitution on the polymer backbone chain due to decrease in ionization potential and increase in electron affinity values. This is expected to enhance the intrinsic conductivity of the resulting copolymer. Use of alternate donor acceptor moieties within the repeat units should maximize the extended {pi} conjugation.

SYNTHESIS AND CHARACTERIZATION OF NOVEL BIPOLAR PPV-BASED COPOLYMER CONTAINING TRIAZOLE AND CARBAZOLE UNITS

Institute of Scientific and Technical Information of China (English)

Ze Liu; Li-xiang Wang; Xia-bin Jing; Fo-song Wang

2001-01-01

Two new blue light-emitting PPV-based conjugated copolymers containing both an electron-withdrawing unit (triazole-TAZ) and electron-rich moieties (carbazole-CAR and bicarbazole-BCAR) were prepared by Wittig condensation polymerization between the triazole diphosphonium salt and the corresponding dialdehyde monomers. Their structures and properties were characterized by FT-IR, TGA, DSC, UV-Vis, PL spectroscopy and electrochemical measurements. The resulting copolymers are soluble in common organic solvents and thermally stable with a Ts of 147C for TAZ-CAR-PPV and of 157C for TAZ-BCAR-PPV. The maximum photoluminescence wavelengths of TAZ-CAR-PPV and TAZ-BCAR-PPV film appear at 460 nm and 480 nm, respectively. Cyclic voltammetry measurement demonstrates that TAZ-BCAR-PPV has good electrochemical reversibility, while TAZ-CAR-PPV exhibits the irreversible redox process. The triazole unit was found to be an effective π-conjugation interrupter and can play the rigid spacer role in determining the emission colour of the resulting copolymer.

Radiation synthesis of a water-soluble temperature sensitive polymer, activated copolymer and applications in immobilization of proteins

International Nuclear Information System (INIS)

Zhai Maolin; Ha Hongfei; Wu Jilan

1993-01-01

In this work the radiation polymerization of N-isopropylacrylamide (NIPAAM) in aqueous solutions has been carried out and a water-soluble, temperature sensitive polymer and copolymer were obtained by using γ-rays from Co-60 source at room temperature. We have gained the optimum dose and dose-rate of radiation synthesis of linear polyNIPAAM through determining conversion yield and viscosity. In order to immobilize protein (BSA) and enzyme (HRP) into this water-soluble polymer, we prepared an activated copolymer, poly(N-isopropylacrylamide-co-N-acryloxysuccinimide). The BSA and HRP has been immobilized onto the activated copolymer. The BSA (HRP)/copolymer conjugates still kept the original thermally sensitive properties of the linear polyNIPAAM. The conjugation yield of BSA to the activated copolymer decreased with increasing dose. Immobilized HRP was stable at 0 o C for a long time and has, at least, 4 days stability at room temperature. Immobilized HRP activity was lowered when the temperature was raised. This phenomenon was reversible and the immobilized HRP regained activity. The optimum pH of the immobilized HRP shifted from ca.5 upward to ca. 7. (author)

Cathepsin B-sensitive polymers for compartment-specific degradation and nucleic acid release.

Science.gov (United States)

Chu, David S H; Johnson, Russell N; Pun, Suzie H

2012-02-10

Degradable cationic polymers are desirable for in vivo nucleic acid delivery because they offer significantly decreased toxicity over non-degradable counterparts. Peptide linkers provide chemical stability and high specificity for particular endopeptidases but have not been extensively studied for nucleic acid delivery applications. In this work, enzymatically degradable peptide-HPMA copolymers were synthesized by RAFT polymerization of HPMA with methacrylamido-terminated peptide macromonomers, resulting in polymers with low polydispersity and near quantitative incorporation of peptides. Three peptide-HPMA copolymers were evaluated: (i) pHCathK(10), containing peptides composed of the linker phe-lys-phe-leu (FKFL), a substrate of the endosomal/lysosomal endopeptidase cathepsin B, connected to oligo-(L)-lysine for nucleic acid binding, (ii) pHCath(D)K(10), containing the FKFL linker with oligo-(D)-lysine, and (iii) pH(D)Cath(D)K(10), containing all (D) amino acids. Cathepsin B degraded copolymers pHCathK(10) and pHCath(D)K(10) within 1 h while no degradation of pH(D)Cath(D)K(10) was observed. Polyplexes formed with pHCathK(10) copolymers show DNA release by 4 h of treatment with cathepsin B; comparatively, polyplexes formed with pHCath(D)K(10) and pH(D)Cath(D)K(10) show no DNA release within 8 h. Transfection efficiency in HeLa and NIH/3T3 cells were comparable between the copolymers but pHCathK(10) was less toxic. This work demonstrates the successful application of peptide linkers for degradable cationic polymers and DNA release. Copyright © 2011 Elsevier B.V. All rights reserved.

Development of Nanomedicines for Treatment of Posttraumatic Osteoarthritis

Science.gov (United States)

2016-03-01

expression and provided sustained inhibition of osteoclast formation. 15. SUBJECT TERMS nanomedicine, PTOA, DMM, osteoarthritis, prodrug, glucocorticoid ...KEYWORDS: Nanomedicine, PTOA, DMM, osteoarthritis, prodrug, glucocorticoid , dexamethasone, HPMA copolymer 3. ACCOMPLISHMENTS: What were the

72/74As-labeling of HPMA based polymers for long-term in vivo PET imaging

DEFF Research Database (Denmark)

Herth, Matthias M; Barz, Matthias; Jahn, Markus

2010-01-01

In the context of molecular imaging, various polymers based on the clinically approved N-(2-hydroxypropyl)-methacrylamide (HPMA) have been radio-labeled using longer-living positron emitters 72As t1/2=26 h or 74As t1/2=17.8 d. This approach may lead to non-invasive determination of the long...

Theory of Primary Photoexcitations in Donor-Acceptor Copolymers.

Science.gov (United States)

Aryanpour, Karan; Dutta, Tirthankar; Huynh, Uyen N V; Vardeny, Zeev Valy; Mazumdar, Sumit

2015-12-31

We present a generic theory of primary photoexcitations in low band gap donor-acceptor conjugated copolymers. Because of the combined effects of strong electron correlations and broken symmetry, there is considerable mixing between a charge-transfer exciton and an energetically proximate triplet-triplet state with an overall spin singlet. The triplet-triplet state, optically forbidden in homopolymers, is allowed in donor-acceptor copolymers. For an intermediate difference in electron affinities of the donor and the acceptor, the triplet-triplet state can have a stronger oscillator strength than the charge-transfer exciton. We discuss the possibility of intramolecular singlet fission from the triplet-triplet state, and how such fission can be detected experimentally.

Features of radiation chemical processes in ethylene-styrene copolymers

International Nuclear Information System (INIS)

Leshchenko, S.S.; Mal'tseva, A.P.; Iskakov, L.I.; Karpov, V.L.

1976-01-01

A study was made of statistical copolymers of ethylene with styrene to determine their structure and properties and radio-chemical transformations. The styrene content of the copolymers ranged from 1 to 85 mole%. The investigation covered non-irradiated copolymers and those irradiated with doses of 1-1000Mrad at room temperature and at liquid nitrogen temperature. It is shown that styrene units present in the CES inhibited all radio-chemical processes compared with PE irradiated under similar conditions. It is suggested that the radiation resistance of CES with styrene contents up to 10 mole % increases in the course of irradiation as a result of the formation of structures with a high degree of conjugation which are more capable of scattering absorbed energy than in the case of phenyl rings by themselves. The most promising of the CES examined is the one with a styrene content of 5 mole %. The mechanical properties of this copolymer are similar to those of PE, and its radiation resistance rises under service conditions in the presence of ionizing radiation

Neutral Polymeric Micelles for RNA Delivery

Science.gov (United States)

Lundy, Brittany B.; Convertine, Anthony; Miteva, Martina; Stayton, Patrick S.

2013-01-01

RNA interference (RNAi) drugs have significant therapeutic potential but delivery systems with appropriate efficacy and toxicity profiles are still needed. Here, we describe a neutral, ampholytic polymeric delivery system based on conjugatable diblock polymer micelles. The diblock copolymer contains a hydrophilic poly[N-(2-hydroxypropyl) methacrylamide-co-N-(2-(pyridin-2- yldisulfanyl)ethyl)methacrylamide) (poly[HPMA-co-PDSMA]) segment to promote aqueous stability and facilitate thiol-disulfide exchange reactions, and a second ampholytic block composed of propyl acrylic acid (PAA), dimethylaminoethyl methacrylate (DMAEMA), and butyl methacrylate (BMA). The poly[(HPMA-co-PDSMA)-b-(PAA-co-DMAEMA-co-BMA)] was synthesized using Reversible Addition-Fragmentation chain Transfer (RAFT) polymerization with an overall molecular weight of 22,000 g/mol and a PDI of 1.88. Dynamic light scattering and fluorescence measurements indicated that the diblock copolymers self-assemble under aqueous conditions to form polymeric micelles with a hydrodynamic radius and critical micelle concentration of 25 nm and 25 μg/mL respectively. Red blood cell hemolysis experiments show that the neutral hydrophilic micelles have potent membrane destabilizing activity at endosomal pH values. Thiolated siRNA targeting glyceraldehyde 3-phosphate dehydrogenase (GAPDH) was directly conjugated to the polymeric micelles via thiol exchange reactions with the pyridal disulfide groups present in the micelle corona. Maximum silencing activity in HeLa cells was observed at a 1:10 molar ratio of siRNA to polymer following a 48 h incubation period. Under these conditions 90 % mRNA knockdown and 65 % and protein knockdown of at 48 h was achieved with negligible toxicity. In contrast the polymeric micelles lacking a pH-responsive endosomalytic segment demonstrated negligible mRNA and protein knockdown under these conditions. The potent mRNA knockdown and excellent biocompatibility of the neutral siRNA conjugates

Conjugated Polymers Containing BODIPY and Fluorene Units for Sensitive Detection of CN− Ions: Site-Selective Synthesis, Photo-Physical and Electrochemical Properties

Directory of Open Access Journals (Sweden)

Tian He

2017-10-01

Full Text Available Conjugated polymers containing distinct molecular units are expected to be very interesting because of their unique properties endowed by these units and the formed conjugated polymers. Herein, four new conjugated copolymers based on fluorene and 4,4’-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY have been designed and synthesized via Sonogashira polymerization. The fluorene unit was attached to the 3,5- or 2,6-positions of BODIPY by ethynylenes or p-diacetylenebenzene. The obtained polymers show good thermal stability and broad absorption in the wavelength range from 300 to 750 nm. The effects of site-selective copolymerization and conjugation length along the polymer backbone on the optoelectronic and electrochemical properties of these copolymers were systematically studied by UV-Vis spectroscopy, photoluminescence (PL and cyclic voltammetry. Besides, it is found that the BODIPY-based copolymers exhibit selectively sensitive responses to cyanide anions, resulting in obvious change of UV-Vis absorption spectra and significant fluorescence quenching of the polymers among various common anions.

A smart polymeric platform for multistage nucleus-targeted anticancer drug delivery.

Science.gov (United States)

Zhong, Jiaju; Li, Lian; Zhu, Xi; Guan, Shan; Yang, Qingqing; Zhou, Zhou; Zhang, Zhirong; Huang, Yuan

2015-10-01

Tumor cell nucleus-targeted delivery of antitumor agents is of great interest in cancer therapy, since the nucleus is one of the most frequent targets of drug action. Here we report a smart polymeric conjugate platform, which utilizes stimulus-responsive strategies to achieve multistage nuclear drug delivery upon systemic administration. The conjugates composed of a backbone based on N-(2-hydroxypropyl) methacrylamide (HPMA) copolymer and detachable nucleus transport sub-units that sensitive to lysosomal enzyme. The sub-units possess a biforked structure with one end conjugated with the model drug, H1 peptide, and the other end conjugated with a novel pH-responsive targeting peptide (R8NLS) that combining the strength of cell penetrating peptide and nuclear localization sequence. The conjugates exhibited prolonged circulation time and excellent tumor homing ability. And the activation of R8NLS in acidic tumor microenvironment facilitated tissue penetration and cellular internalization. Once internalized into the cell, the sub-units were unleashed for nuclear transport through nuclear pore complex. The unique features resulted in 50-fold increase of nuclear drug accumulation relative to the original polymer-drug conjugates in vitro, and excellent in vivo nuclear drug delivery efficiency. Our report provides a strategy in systemic nuclear drug delivery by combining the microenvironment-responsive structure and detachable sub-units. Copyright © 2015 Elsevier Ltd. All rights reserved.

Carboxylic Terminated Thermo-Responsive Copolymer Hydrogel and Improvement in Peptide Release Profile

Directory of Open Access Journals (Sweden)

Zi-Kun Rao

2018-02-01

Full Text Available To improve the release profile of peptide drugs, thermos-responsive triblock copolymer poly (ε-caprolactone-co-p-dioxanone-b-poly (ethylene glycol-b-poly (ε-caprolactone-co-p-dioxanone (PECP was prepared and end capped by succinic anhydride to give its carboxylic terminated derivative. Both PCEP block copolymer and its end group modified derivative showed temperature-dependent reversible sol-gel transition in water. The carboxylic end group could significantly decrease the sol-gel transition temperature by nearly 10 °C and strengthen the gel due to enhanced intermolecular force among triblock copolymer chains. Furthermore, compared with the original PECP triblock copolymer, HOOC–PECP–COOH copolymer displayed a retarded and sustained release profile for leuprorelin acetate over one month while effectively avoiding the initial burst. The controlled release was believed to be related to the formation of conjugated copolymer-peptide pair by ionic interaction and enhanced solubility of drug molecules into the hydrophobic domains of the hydrogel. Therefore, carboxyl terminated HOOC–PECP–COOH hydrogel was a promising and well-exhibited sustained release carrier for peptide drugs with the advantage of being able to develop injectable formulation by simple mixing.

Curdlan-conjugated PLGA nanoparticles possess macrophage stimulant activity and drug delivery capabilities

CSIR Research Space (South Africa)

Tukulula, M

2015-02-01

Full Text Available There is significant interest in the application of nanoparticles to deliver immunostimulatory signals to cells. We hypothesized that curdlan (immune stimulating polymer) could be conjugated to PLGA and nanoparticles from this copolymer would...

HPMA-based drug delivery system and its interactions of human serum albumin: SAXS, ITC, and NMR study

Czech Academy of Sciences Publication Activity Database

Filippov, Sergey K.; Kaberov, Leonid; Zhang, X.; Niebuur, B.-J.; Chytil, Petr; Etrych, Tomáš; Wieland, F.; Velychkivska, Nadiia; Starovoytova, Larisa; Svergun, D.; Papadakis, C.

2017-01-01

Roč. 254, 20 August (2017), s. 455 ISSN 0065-7727. [ACS National Meeting & Exposition /254./. 20.08.2017-24.08.2017, Washington] R&D Projects: GA ČR(CZ) GC15-10527J Institutional support: RVO:61389013 Keywords : HPMA * human serum albumin * SAXS Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry

Anthradithiophene-Containing Copolymers for Thin-Film Transistors and Photovoltaic Cells

KAUST Repository

Jiang, Ying

2010-08-10

We synthesized anthradithiophene-cyclopentadithiophene conjugated copolymers via Stille coupling. The anthradithiophene core was verified to be superior in stability compared to pentacene toward Diels-Alder cycloaddition and therefore more compatible with fullerenes, acceptor material commonly used in bulk heterojunction (BHJ) photovoltaic cells. The polymers exhibit high film absorption coefficients of 105 cm-1, an order of magnitude higher than previously reported anthradithiophene-dialkylfluorene copolymers. Short-circuit currents exceeding 5 mA/cm2 and a BHJ device efficiency close to 1% were achieved when device morphology was improved with diiodooctane as a solvent additive. This is the highest power conversion efficiency achieved by an acene-containing polymer so far. © 2010 American Chemical Society.

Synthesis and functions of well-defined polymer-drug conjugates as efficient nanocarriers for intravesical chemotherapy of bladder cancer(a).

Science.gov (United States)

Yu, Qingsong; Zhang, Jiajing; Zhang, Guan; Gan, Zhihua

2015-04-01

Novel poly(ethylene glycol) and poly(N-(2-hydroxypropyl)methacrylamide) block copolymer (PEG-b-PHPMA) with well-defined composition was synthesized by RAFT polymerization. Folate and doxorubicin (DOX) were quantitatively introduced into the copolymer. The influences of folate content and pH value on folate receptor (FR) mediated cell endocytosis and pH-responsive DOX release were studied. It has been demonstrated that minimum folate content is needed for the enrichment of hydrophobic folate on the hydrophilic part of polymer conjugates. The cytotoxicity of targetable polymer drug conjugates was much higher than that of non-targetable ones and free DOX. It could be concluded that the folate plays a significant role in targeting and internalization of the conjugates against bladder cancer cells. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The influence of a colonic microbiota on HPMA copolymer lectin conjugates binding in rodent intestine

Czech Academy of Sciences Publication Activity Database

Wróblewski, S.; Říhová, Blanka; Rossmann, Pavel; Hudcovic, Tomáš; Řeháková, Zuzana; Kopečková, P.; Kopeček, J.

2001-01-01

Roč. 9, č. 2 (2001), s. 85-94 ISSN 1061-186X R&D Projects: GA MPO PZ-Z2/24 Institutional research plan: CEZ:AV0Z5020903 Keywords : colonic microflora * germ-free * glycoproteins Subject RIV: EC - Immunology Impact factor: 2.186, year: 2001

Synthesis and Properties of 1,8-Carbazole-Based Conjugated Copolymers

Directory of Open Access Journals (Sweden)

Tsuyoshi Michinobu

2010-07-01

Full Text Available A new series of conjugated carbazole polymers based on the 1,8-carbazolylene unit was synthesized by the Pd-catalyzed polycondensation between the 1,8-diiodocarbazole derivative and various bifunctional counter comonomers. An alkyne spacer was found to be a key to increasing the molecular weight of the resulting polymers. All the obtained polymers showed good solubilities in the common organic solvents, and they were fully characterized by Gel permeation chromatography (GPC, and 1H NMR and infrared (IR spectroscopies. The UV-vis absorption and fluorescence spectra revealed the relationship between the chemical structure and effective conjugation length. The efficiency order of the carbazole connectivity was 2,7-carbazolylene > 1,8-carbazolylene > 3,6-carbazolylene. The electrochemical properties of these polymers suggested the relatively facile oxidation at ca. +0.5–0.7 V vs. Fc/Fc+ or a high potential as p-type semiconductors. The combination of the electrochemical oxidation potentials and the optical band gaps allowed us to estimate the HOMO and LUMO levels of the polymers. It was shown that the energy levels of the 1,8-carbazole-based conjugated polymers can be tunable by selecting the appropriate comonomer structures.

Peptide–polymer ligands for a tandem WW-domain, an adaptive multivalent protein–protein interaction: lessons on the thermodynamic fitness of flexible ligands

Directory of Open Access Journals (Sweden)

Katharina Koschek

2015-05-01

Full Text Available Three polymers, poly(N-(2-hydroxypropylmethacrylamide (pHPMA, hyperbranched polyglycerol (hPG, and dextran were investigated as carriers for multivalent ligands targeting the adaptive tandem WW-domain of formin-binding protein (FBP21. Polymer carriers were conjugated with 3–9 copies of the proline-rich decapeptide GPPPRGPPPR-NH2 (P1. Binding of the obtained peptide–polymer conjugates to the tandem WW-domain was investigated employing isothermal titration calorimetry (ITC to determine the binding affinity, the enthalpic and entropic contributions to free binding energy, and the stoichiometry of binding for all peptide–polymer conjugates. Binding affinities of all multivalent ligands were in the µM range, strongly amplified compared to the monovalent ligand P1 with a KD > 1 mM. In addition, concise differences were observed, pHPMA and hPG carriers showed moderate affinity and bound 2.3–2.8 peptides per protein binding site resulting in the formation of aggregates. Dextran-based conjugates displayed affinities down to 1.2 µM, forming complexes with low stoichiometry, and no precipitation. Experimental results were compared with parameters obtained from molecular dynamics simulations in order to understand the observed differences between the three carrier materials. In summary, the more rigid and condensed peptide–polymer conjugates based on the dextran scaffold seem to be superior to induce multivalent binding and to increase affinity, while the more flexible and dendritic polymers, pHPMA and hPG are suitable to induce crosslinking upon binding.

Synthesis of Donor-Acceptor Conjugated Polymers by "CLICK" Polymerization for OPV applications

DEFF Research Database (Denmark)

Brandt, Rasmus Guldbæk; Yu, Donghong

The intent of this study was to utilize the Copper(I)-catalyzed Azide Alkyne Cycloaddition (CuAAC) as a polymerization technique (“Click” Polymerization) for synthesizing novel π-conjugated low band gap polymers for organic photovoltaic applications (OPV). The chosen approach was to synthesize...... an alternating electron donating (donor, D) and electron withdrawing (acceptor, A) co-polymer. The chosen monomers were well known units, and the novelty lies in using the monomer units with the click methodology. An insoluble alternating copolymer consisting of 2,7-diazido-9,9-dioctyl-9Hflourene and 1...

Immunogenicity of coiled-coil based drug-free macromolecular therapeutics

Czech Academy of Sciences Publication Activity Database

Kverka, Miloslav; Hartley, J.M.; Chu, T.W.; Yang, J.; Heidchen, R.; Kopeček, J.

2014-01-01

Roč. 35, č. 2 (2014), s. 5886-5896 ISSN 1616-0177 R&D Projects: GA MŠk(CZ) EE2.3.30.0003 Grant - others:NIH(US) GM095606 Institutional support: RVO:61388971 Keywords : coiled-coil * enantiomers * HPMA copolymer Subject RIV: EC - Immunology

Pluronic-lysozyme conjugates as anti-adhesive and antibacterial bifunctional polymers for surface coating

NARCIS (Netherlands)

Muszanska, A.K.; Busscher, H.J.; Herrmann, A.; Mei, van der H.C.; Norde, W.

2011-01-01

This paper describes the preparation and characterization of polymer protein conjugates composed of a synthetic triblock copolymer with a central polypropylene oxide (PPO) block and two terminal polyethylene oxide (PEO) segments, Pluronic F-127, and the antibacterial enzyme lysozyme attached to the

Synthesis and Characterization of Smart Block Copolymers for Biomineralization and Biomedical Applications

Energy Technology Data Exchange (ETDEWEB)

Kanapathipillai, Mathumai [Iowa State Univ., Ames, IA (United States)

2008-01-01

moieties depends on the pH of the solution. Polymers with polyzwitterions, anions and cations have been shown to exhibit pH responsive self assembly. Other stimuli responsive polymers include glucose sensitive polymers, calcium ion-sensitive polymers and so on. Progress in living radical polymerization (LRP) methods [10] has made it possible for the facile synthesis of these block copolymer systems with controlled molecular weights and well defined architectures. The overall theme of this work is to develop novel smart block copolymers for biomineralization and biomedical applications. Synthesis and characterization of self-assembling thermoreversible ionic block copolymers as templates in biomimetic nanocomposite synthesis using a bottom-up approach is a novel contribution in this respect. Further, we have extended these families of copolymers to include block copolymer-peptide conjugates to enhance biological specificity. Future directions on this work will focus on enhancing the polymer templating properties for biomineralization by expanding the family of block copolymers with organic polypeptides and biological polypeptide scaffolds as well as a detailed understanding of the polymer-inorganic nanocomposites at the molecular level using small angle scattering analysis. Glucose responsive polymer hydrogels for drug delivery, polymer-ligand conjugates for non-viral therapy and thermoresponsive injectable photocrosslinkable hydrogels for posttraumatic arthritis cartilage healing are other applications of these novel copolymers synthesized in our work.

Exploring Tyrosine-Triazolinedione (TAD) Reactions for the Selective Conjugation and Cross-Linking of N-Carboxyanhydride (NCA) Derived Synthetic Copolypeptides.

Science.gov (United States)

Hanay, Saltuk B; Ritzen, Bas; Brougham, Dermot; Dias, Aylvin A; Heise, Andreas

2017-07-01

Highly efficient functionalization and cross-linking of polypeptides is achieved via tyrosine-triazolinedione (TAD) conjugation chemistry. The feasibility of the reaction is demonstrated by the reaction of 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD) with tyrosine containing block copolymer poly(ethylene glycol)-Tyr 4 as well as a statistical copolymer of tyrosine and lysine (poly(Lys 40 -st-Tyr 10 )) prepared form N-carboxyanhydride polymerization. Selective reaction of PTAD with the tyrosine units is obtained and verified by size exclusion chromatography and NMR spectroscopy. Moreover, two monofunctional and two difunctional TAD molecules are synthesized. It is found that their stability in the aqueous reaction media significantly varied. Under optimized reaction conditions selective functionalization and cross-linking, yielding polypeptide hydrogels, can be achieved. TAD-mediated conjugation can offer an interesting addition in the toolbox of selective (click-like) polypeptide conjugation methodologies as it does not require functional non-natural amino acids. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Peptide-conjugated micelles as a targeting nanocarrier for gene delivery

Energy Technology Data Exchange (ETDEWEB)

Lin, Wen Jen, E-mail: wjlin@ntu.edu.tw; Chien, Wei Hsuan [National Taiwan University, School of Pharmacy, Graduate Institute of Pharmaceutical Sciences (China)

2015-09-15

The aim of this study was to develop peptide-conjugated micelles possessing epidermal growth factor receptor (EGFR) targeting ability for gene delivery. A sequence-modified dodecylpeptide, GE11(2R), with enhancing EGF receptor binding affinity, was applied in this study as a targeting ligand. The active targeting micelles were composed of poly(d,l-lactide-co-glycolide)-poly(ethylene glycol) (PLGA-PEG) copolymer conjugated with GE11(2R)-peptide. The particle sizes of peptide-free and peptide-conjugated micelles were 277.0 ± 5.1 and 308.7 ± 14.5 nm, respectively. The peptide-conjugated micelles demonstrated the cellular uptake significantly higher than peptide-free micelles in EGFR high-expressed MDA-MB-231 and MDA-MB-468 cells due to GE11(2R)-peptide specificity. Furthermore, the peptide-conjugated micelles were able to encapsulate plasmid DNA and expressed cellular transfection higher than peptide-free micelles in EGFR high-expressed cells. The EGFR-targeting delivery micelles enhanced DNA internalized into cells and achieved higher cellular transfection in EGFR high-expressed cells.

Developments in the chemistry and band gap engineering of donor-acceptor substituted conjugated polymers

NARCIS (Netherlands)

Mullekom, van H.A.M.; Vekemans, J.A.J.M.; Havinga, E.E.; Meijer, E.W.

2001-01-01

This paper reviews the tools to manipulate and minimize the band gap of conjugated (co)polymers. The effects of minimization of the bond length alternation and of the incorporation of donor-K-acceptor units are discussed in particular. A systematic study of a series of alternating donor-acceptor

Hydrolytically degradable polymer micelles for anticancer drug delivery to solid tumors

Czech Academy of Sciences Publication Activity Database

Chytil, Petr; Etrych, Tomáš; Kostka, Libor; Ulbrich, Karel

2012-01-01

Roč. 213, č. 8 (2012), s. 858-867 ISSN 1022-1352 R&D Projects: GA AV ČR IAAX00500803; GA ČR GAP301/11/0325 Institutional research plan: CEZ:AV0Z40500505 Keywords : HPMA copolymers * drug delivery systems * doxorubicin Subject RIV: EC - Immunology Impact factor: 2.386, year: 2012

Nanostructure of self-assembled rod-coil block copolymer films for photovoltaic applications

International Nuclear Information System (INIS)

Heiser, T.; Adamopoulos, G.; Brinkmann, M.; Giovanella, U.; Ould-Saad, S.; Brochon, C.; Wetering, K. van de; Hadziioannou, G.

2006-01-01

The nanostructures of a series of rod-coil block copolymers, designed for photovoltaic applications, are studied by atomic force microscopy and transmission electron microscopy. The copolymers are composed of a semiconducting poly-p-phenylenevinylene rod with (2'-ethyl)-hexyloxy side chains and a functionalized coil block of various length and flexibility. Both, as deposited and annealed block copolymer films were investigated. The results show that highly ordered structures are only obtained if the coil block is characterized by a glass transition temperature which is significantly lower than the melting temperature of the alkyl side chains. For this material a high molecular mobility and strong driving force for crystallization of the rigid block can be achieved simultaneously. For the smallest coil to rod length ratio, we found a lamellar morphology with perpendicularly oriented lamellae with respect to the substrate. Electron diffraction data show the presence of a periodical molecular arrangement with a characteristic distance of 0.94 nm that is attributed to the distance between conjugated chains separated by the layers of alkyl sidechains

Nanostructure of self-assembled rod-coil block copolymer films for photovoltaic applications

Energy Technology Data Exchange (ETDEWEB)

Heiser, T. [Institut d' Electronique du Solide et des Systemes (InESS), CNRS/ULP, 23, rue du Loess, F-67037 Strasbourg Cedex 2 (France)]. E-mail: Thomas.Heiser@iness.c-strasbourg.fr; Adamopoulos, G. [Laboratoire d' Ingenierie des Polymeres pour les Hautes Technologies (LIPHT), Ecole Europeenne de Chimie Polymeres et Materiaux (ECPM), 25, rue Becquerel, F-67087 Strasbourg Cedex 2 (France); Brinkmann, M. [Institut Charles Sadron (ICS), CNRS, 6, rue Boussingault, F-67083 Strasbourg Cedex (France); Giovanella, U. [Laboratoire d' Ingenierie des Polymeres pour les Hautes Technologies (LIPHT), Ecole Europeenne de Chimie Polymeres et Materiaux (ECPM), 25, rue Becquerel, F-67087 Strasbourg Cedex 2 (France); Ould-Saad, S. [Institut d' Electronique du Solide et des Systemes (InESS), CNRS/ULP, 23, rue du Loess, F-67037 Strasbourg Cedex 2 (France); Brochon, C. [Laboratoire d' Ingenierie des Polymeres pour les Hautes Technologies (LIPHT), Ecole Europeenne de Chimie Polymeres et Materiaux (ECPM), 25, rue Becquerel, F-67087 Strasbourg Cedex 2 (France); Wetering, K. van de [Laboratoire d' Ingenierie des Polymeres pour les Hautes Technologies (LIPHT), Ecole Europeenne de Chimie Polymeres et Materiaux (ECPM), 25, rue Becquerel, F-67087 Strasbourg Cedex 2 (France); Hadziioannou, G. [Laboratoire d' Ingenierie des Polymeres pour les Hautes Technologies (LIPHT), Ecole Europeenne de Chimie Polymeres et Materiaux (ECPM), 25, rue Becquerel, F-67087 Strasbourg Cedex 2 (France)

2006-07-26

The nanostructures of a series of rod-coil block copolymers, designed for photovoltaic applications, are studied by atomic force microscopy and transmission electron microscopy. The copolymers are composed of a semiconducting poly-p-phenylenevinylene rod with (2'-ethyl)-hexyloxy side chains and a functionalized coil block of various length and flexibility. Both, as deposited and annealed block copolymer films were investigated. The results show that highly ordered structures are only obtained if the coil block is characterized by a glass transition temperature which is significantly lower than the melting temperature of the alkyl side chains. For this material a high molecular mobility and strong driving force for crystallization of the rigid block can be achieved simultaneously. For the smallest coil to rod length ratio, we found a lamellar morphology with perpendicularly oriented lamellae with respect to the substrate. Electron diffraction data show the presence of a periodical molecular arrangement with a characteristic distance of 0.94 nm that is attributed to the distance between conjugated chains separated by the layers of alkyl sidechains.

Synergistic effect of EMF-BEMER-type pulsed weak electromagnetic field and HPMA-bound doxorubicin on mouse EL4 T-cell lymphoma

Czech Academy of Sciences Publication Activity Database

Říhová, Blanka; Etrych, Tomáš; Šírová, Milada; Tomala, Jakub; Ulbrich, Karel; Kovář, Marek

2011-01-01

Roč. 19, č. 10 (2011), s. 890-899 ISSN 1061-186X R&D Projects: GA AV ČR IAA400200702 Institutional research plan: CEZ:AV0Z50200510; CEZ:AV0Z40500505 Keywords : EL4 T-cell lymphoma * athymic mice * DOX(HYD)-HPMA Subject RIV: EC - Immunology Impact factor: 2.696, year: 2011

Solution-Processable Balanced Ambipolar Field-Effect Transistors Based on Carbonyl-Regulated Copolymers.

Science.gov (United States)

Yang, Chengdong; Fang, Renren; Yang, Xiongfa; Chen, Ru; Gao, Jianhua; Fan, Hanghong; Li, Hongxiang; Hu, Wenping

2018-04-04

It is very important to develop ambipolar field effect transistors to construct complementary circuits. To obtain balanced hole- and electron-transport properties, one of the key issues is to regulate the energy levels of the frontier orbitals of the semiconductor materials by structural tailoring, so that they match well with the electrode Fermi levels. Five conjugated copolymers were synthesized and exhibited low LUMO energy levels and narrow bandgaps on account of the strong electron-withdrawing effect of the carbonyl groups. Polymer thin film transistors were prepared by using a solution method and exhibited high and balanced hole and electron mobility of up to 0.46 cm 2  V -1  s -1 , which suggested that these copolymers are promising ambipolar semiconductor materials. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Evaluation of dementia by acrolein, amyloid-β and creatinine.

Science.gov (United States)

Igarashi, Kazuei; Yoshida, Madoka; Waragai, Masaaki; Kashiwagi, Keiko

2015-10-23

Plasma, urine and cerebrospinal fluid (CSF) were examined for biochemical markers of dementia. Protein-conjugated acrolein (PC-Acro) and the amyloid-β (Aβ)40/42 ratio in plasma can be used to detect mild cognitive impairment (MCI) and Alzheimer's disease (AD). In plasma, PC-Acro and the Aβ40/42 ratio in MCI and AD were significantly higher relative to non-demented subjects. Furthermore, urine acrolein metabolite, 3-hydroxypropyl mercapturic acid (3-HPMA)/creatinine (Cre) and amino acid-conjugated acrolein (AC-Acro)/Cre in AD were significantly lower than MCI. It was also shown that reduced urine 3-HPMA/Cre correlated with increased plasma Aβ40/42 ratio in dementia. The Aβ40/PC-Acro ratio in CSF, together with Aβ40 and Aβ40/42 ratio, was lower in AD than MCI. Increased plasma PC-Acro and Aβ40/42 ratio and decreased urine 3-HPMA/Cre correlated with cognitive ability (MMSE). These results indicate that the measurements of acrolein derivatives together with Aβ and Cre in biologic fluids is useful to estimate severity of dementia. Copyright © 2015 Elsevier B.V. All rights reserved.

Copolymers containing meta-pyridylvinylene and para-arylenevinylene fragments: synthesis, quaternization reaction, and photophysical properties

Science.gov (United States)

Barashkov, Nikolay N.; Olivos, Hernando J.; Ferraris, John P.

1997-12-01

We report the Wittig reaction of the diphosphonium salt of 2,6-bis(chloromethyl)pyridine with terephthaldehyde, 2.5- dioctyloxyterephthaldehyde, or 9,10-anthracenedicarbaldehyde to form conjugated copolymers with fragments of 2,6 - pyridylene and para-arylenevinylene. The protonation reaction of poly(para-arylenevinylene)-co-(meta- pyridylvinylene) with hydrochloric acid and the quaternization reaction of poly(2,5-dioctyloxy-1,4- phenylenevinylene)-co-(2,6-pyridylvinylene) with methyl triflate have been investigated by spectrophotometric and fluorescent methods. The absorption, excitation and fluorescence spectra of these copolymers as well as their corresponding model compounds were studied and compared. The photophysical properties of the investigated polymers suggest that these materials could be good candidates for the fabrication of efficient blue and green light-emitting diodes.

Peptide-targeted polymer cancerostatics

Czech Academy of Sciences Publication Activity Database

Böhmová, Eliška; Pola, Robert

2016-01-01

Roč. 65, Suppl. 2 (2016), S153-S164 ISSN 0862-8408 R&D Projects: GA MŠk(CZ) LO1507 Institutional support: RVO:61389013 Keywords : HPMA copolymers * tumor targeting * peptides Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.461, year: 2016 http://www.biomed.cas.cz/physiolres/pdf/65%20Suppl%202/65_S153.pdf

High-molecular-weight polymers containing biodegradable disulfide bonds: synthesis and in vitro verification of intracellular degradation

Czech Academy of Sciences Publication Activity Database

Etrych, Tomáš; Kovář, Lubomír; Šubr, Vladimír; Braunová, Alena; Pechar, Michal; Chytil, Petr; Říhová, Blanka; Ulbrich, Karel

2010-01-01

Roč. 25, č. 1 (2010), s. 5-26 ISSN 0883-9115 R&D Projects: GA AV ČR IAA400500806; GA AV ČR KAN200200651 Institutional research plan: CEZ:AV0Z40500505; CEZ:AV0Z50200510 Keywords : water-soluble polymers * reductive degradation * HPMA copolymers Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.610, year: 2010

HPMA copolymer-doxorubicin conjugates: the effects of molecular weight and architecture on biodistribution and in vivo activity

Czech Academy of Sciences Publication Activity Database

Etrych, Tomáš; Šubr, Vladimír; Strohalm, Jiří; Šírová, Milada; Říhová, Blanka; Ulbrich, Karel

2012-01-01

Roč. 164, č. 3 (2012), s. 346-354 ISSN 0168-3659. [European Symposium on Controlled Drug Delivery /12./. Egmond aan Zee, 04.04.2012-06.04.2012] R&D Projects: GA AV ČR IAAX00500803; GA ČR GAP301/11/0325 Institutional research plan: CEZ:AV0Z40500505; CEZ:AV0Z50200510 Institutional support: RVO:61389013 ; RVO:61388971 Keywords : drug delivery * tumour accumulation * body distribution Subject RIV: CD - Macromolecular Chemistry; EC - Immunology (MBU-M) Impact factor: 7.633, year: 2012

Construction of hydroxypropyl-{beta}-cyclodextrin copolymer nanoparticles and targeting delivery of paclitaxel

Energy Technology Data Exchange (ETDEWEB)

Miao Qinghua; Li Suping; Han Siyuan [National Center for Nanoscience and Technology of China, CAS Key Laboratory for Biological Effects of Nanomaterials and Nanosafety (China); Wang Zhi, E-mail: wangzhi@jlu.edu.cn [Jilin University, Key Laboratory for Molecular Enzymology and Engineering, Ministry of Education (China); Wu Yan, E-mail: wuy@nanoctr.cn; Nie Guangjun, E-mail: niegj@nanoctr.cn [National Center for Nanoscience and Technology of China, CAS Key Laboratory for Biological Effects of Nanomaterials and Nanosafety (China)

2012-08-15

A novel amphiphilic copolymer with p-maleimidophenyl isocyanate-hydroxypropyl-{beta}-cyclodextrin-polylactide-1, 2-dipalmitoyl-sn-glycero-3-phosphoethanolamine to generate copolymer nanoparticles (NPs) has been designed. In order to develop an active targeting system, integrin {alpha}{sub v}{beta}{sub 3}-specific targeting peptide cyclo(Arg-Gly-Asp-D-Phe-Cys), cRGD, was conjugated to the surface of NPs (NPs-RGD). These NPs were used to encapsulate anti-tumor drug, paclitaxel. The resulting NPs exhibited high drug-loading capacity and controlled drug release in vitro at acidic pH. In vitro cytotoxicity assay demonstrates that paclitaxel-loaded NPs-RGD significantly inhibited B16 tumor cell (high {alpha}{sub v}{beta}{sub 3}) proliferation relative to free paclitaxel and paclitaxel-loaded NPs at high concentrations. Paclitaxel-loaded NPs-RGD localized mainly in lysosomes in B16 cells as revealed by confocal microscopy. These results suggest a novel strategy for fabrication-functionalizing hydroxypropyl-{beta}-cyclodextrin copolymer nanoparticles for targeting delivery of paclitaxel to integrin {alpha}{sub v}{beta}{sub 3}-rich tumor cells. These nanocarriers can be readily extended to couple other bioactive molecules for active targeting and delivery of various chemotherapeutic drugs.

Using cyclopenta[2,1-b:3,4-c']dithiophene-4-one as a building block for low-bandgap conjugated copolymers applied in solar cells.

Science.gov (United States)

Zhang, Wei; Cao, Jiamin; Liu, Ying; Xiao, Zuo; Zhu, Weiguo; Zuo, Qiqun; Ding, Liming

2012-09-26

A novel electron-accepting unit cyclopenta[2,1-b:3,4-c']dithiophene-4-one (CPDTO-c'), which is an isomer of CPDTO-b' was developed. CPDTO-c' can be incorporated into the D-A backbone through 5, 7 positions. The 2 position of CPDTO-c' can be easily functionalized with an electron-withdrawing chain. By copolymerizing CPDTO-c' with four different donor units: benzo[1,2-b:4,5-b']dithiophene (BDT), dithieno[3,2-b:2',3'-d]silole (DTS), carbazole, and fluorene, four new conjugated copolymers P1-P4 were obtained. All these polymers have good solubility and low-lying HOMO energy levels (-5.41 ∼ -5.92 eV). Among them, P1 and P2 exhibit broad absorption and narrow optical bandgaps of 1.91 and 1.72 eV, respectively. Solar cells based on P1/PC(71) BM afforded a PCE up to 2.72% and a high V(oc) up to ∼0.9 V. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A new formulation of curcumin using poly (lactic-co-glycolic acid)—polyethylene glycol diblock copolymer as carrier material

International Nuclear Information System (INIS)

Tuyen Dao, Thi Phuong; Nguyen, To Hoai; To, Van Vinh; Ho, Thanh Ha; Nguyen, Tuan Anh; Dang, Mau Chien

2014-01-01

The aim of this study is to fabricate a nanoparticle formulation of curcumin using a relatively new vehicle as the matrix polymer: poly(lactic-co-glycolic acid) (PLGA)- polyethylene glycol (PEG) diblock copolymer, and to investigate the effects of the various processing parameters on the characteristics of nanoparticles (NPs). We successfully synthesized the matrix polymer of PLGA-PEG by conjugation of PLGA copolymer with a carboxylate end group to a heterobifunctional amine-PEG-methoxy using N-(3-dimethylaminopropyl)-N’-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide as conjugation crosslinkers. The composition of the formed product (PLGA-PEG) was characterized with 500 MHz 1 H nuclear magnetic resonance (NMR). The conjugation of PLGA-PEG was confirmed using Fourier transform infrared (FTIR) spectrum study. This diblock copolymer was then used to prepare the curcumin-loaded NPs through nanoprecipitation technique. With this method, we found that the size distribution depends on the type of solvent, the concentration of polymer and the concentration of surfactant. The particle size and size distribution were measured by dynamic light scattering (DLS). Transmission electron microscope (TEM) and scanning electron microscope (SEM) were used to confirm the size, structure and morphology of the successfully prepared NPs. All of our results showed that they are spherical and quite homologous with mean diameter around of 100–300 nm. Further, we evaluated encapsulation efficiency and some characteristics of NPs through high performance liquid chromatography (HPLC) analyses, zeta-potential measurements and x-ray diffraction studies. The HPLC analyses were performed to determine the amount of curcumin entrapped in NPs. The zeta-potential measurements confirmed the stability of NPs and the successful encapsulation of curcumin within NPs and the x-ray diffraction patterns showed the disordered-crystalline phase of curcumin inside the polymeric matrix. (paper)

Linear optical absorption response of poly(vinylidene fluoride - trifluoroethylene) copolymers to high gamma dose

International Nuclear Information System (INIS)

Medeiros, Adriana S.

2009-01-01

Poly(vinylidene fluoride) [PVDF] is a semicrystalline linear homopolymer composed by the repetition of CH 2 - CF 2 monomers. The Poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] is a copolymer which is obtained with the random introduction of fluorinated CHF-CF 2 monomers in the PVDF main chain. PVDF, and also its copolymers with TrFE contents ranging from 18 to 63 wt. %, have long been studied for their striking ferroelectric properties and their applications in actuators, transducers and ferroelectric memory. Recent research work around the world have demonstrated that, for TrFE contents ranging from with 30 to 50 wt. %, the copolymer can have its ferroelectric properties modified by high doses of ionizing radiation, with the appearing of radio-induced relaxor ferroelectric features. These studies have lead us to investigate the possible use of these copolymers as high dose dosemeters, once the reported amount of induced C=C conjugated bonds after X-ray, UV and gamma irradiation seems to be a function of the delivered radiation dose. In a first investigation for doses ranging from 0.1 to 100 kGy we found out a linear relation between the gamma radiation dose and the absorption peak intensities in the UV region of the spectrum, i.e., at 223 and 274 nm. The absorption peak at 223 nm is the most sensitive to gamma rays and can be used for detecting gamma doses ranging from 0.3 to 75 kGy. Simultaneously, the absorption peak at 274 nm can be used for doses ranging from 1 to 100 kGy. Now, in the present work, we extended the investigation to gamma doses up to 3 MGy. Particularly, this study is focused in the optical absorption peak at 274 nm, corresponding to the radio-induction of triplets of conjugated C=C double bonds. The investigation revealed a linear correlation between the gamma dose and peak intensity at 274 nm for gamma doses ranging from 0.1 to more than 750 KGy, with a huge extension of the original usable dose range. Calorimetric data revealed a

Macromolecular HPMA-based nanoparticles with cholesterol for solid-tumor targeting: detailed study of the inner structure of a highly efficient drug delivery system

Czech Academy of Sciences Publication Activity Database

Filippov, Sergey K.; Chytil, Petr; Konarev, P. V.; Dyakonova, M.; Papadakis, C. M.; Zhigunov, Alexander; Pleštil, Josef; Štěpánek, Petr; Etrych, Tomáš; Ulbrich, Karel; Svergun, D. I.

2012-01-01

Roč. 13, č. 8 (2012), s. 2594-2604 ISSN 1525-7797 R&D Projects: GA MŠk ME09059; GA AV ČR IAAX00500803; GA ČR GAP108/12/0640 Institutional research plan: CEZ:AV0Z40500505 Institutional support: RVO:61389013 Keywords : HPMA * cholesterol * SAXS Subject RIV: CD - Macromolecular Chemistry Impact factor: 5.371, year: 2012

Acid-labile pHPMA modification of four-arm oligoaminoamide pDNA polyplexes balances shielding and gene transfer activity in vitro and in vivo

Czech Academy of Sciences Publication Activity Database

Beckert, L.; Kostka, Libor; Kessel, E.; Krhac Levacic, A.; Kostková, Hana; Etrych, Tomáš; Lächelt, U.; Wagner, E.

2016-01-01

Roč. 105, August (2016), s. 85-96 ISSN 0939-6411 R&D Projects: GA MŠk(CZ) LO1507; GA MŠk(CZ) LQ1604; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61389013 Keywords : pH-sensitive shielding * pHPMA * AzMMMan Subject RIV: CD - Macromolecular Chemistry Impact factor: 4.159, year: 2016

Studies of P(VDF-HFP) copolymer applied to gamma dosimetry

International Nuclear Information System (INIS)

Liz, Otavio S.R.; Medeiros, Adriana S.

2011-01-01

When polymeric materials are irradiated by ionizing radiation, the effects are roughly divided into two types, degradation (chain scission) and chain link (crosslinking). These effects are normally identified by spectroscopic analysis in the UV-Vis and Infrared region. Recently, the intensities of optical absorption in the ultraviolet visible region (273 nm) due to radio-induction of conjugated C = C bonds in P(VDF-TrFE) copolymers have been successfully used for high dose gamma dosimetry, for doses ranging from 0.1 to 200 kGy. In this context, there is now an interest to conduct a similar systematic investigation of another fluorinated copolymer of PVDF, the poly(fluorovinylidene-co-hexafluoropropylene) [P(VDF-HFP)], not only in the UV-VIS region but also in the near and mid-infrared region. The copolymer used was obtained by randomly adding 10% molar of [CF2- CF-CF3] monomers in the [CH2-CF2]n main chain of PVDF homopolymer. Preliminary results have shown that the irradiated copolymer has characteristic absorption bands originated by irradiation in the FTIR spectrum. It was found that the 1852 cm -1 band, associated with C = O bonds, have a linear correlation with the absorbed dose for doses ranging from 10 to 750 kGy. The absorption band at 1729 cm -1 , associated to chain oxidation (C = O), has shown a similar behavior and can be used to measure doses from 100 to 1000 kGy. These results indicate that the FTIR absorption bands of gamma irradiated P (VDF-HFP) have great potential to be used in high dose dosimetry, without the addition of dyes. (author)

Studies of P(VDF-HFP) copolymer applied to gamma dosimetry

Energy Technology Data Exchange (ETDEWEB)

Liz, Otavio S.R.; Medeiros, Adriana S. [Universidade Federal de Minas Gerais (DEN/UFMG), Belo Horizonte, MG (Brazil). Dept. de Engenharia Nuclear; Faria, Luiz O., E-mail: farialo@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

2011-07-01

When polymeric materials are irradiated by ionizing radiation, the effects are roughly divided into two types, degradation (chain scission) and chain link (crosslinking). These effects are normally identified by spectroscopic analysis in the UV-Vis and Infrared region. Recently, the intensities of optical absorption in the ultraviolet visible region (273 nm) due to radio-induction of conjugated C = C bonds in P(VDF-TrFE) copolymers have been successfully used for high dose gamma dosimetry, for doses ranging from 0.1 to 200 kGy. In this context, there is now an interest to conduct a similar systematic investigation of another fluorinated copolymer of PVDF, the poly(fluorovinylidene-co-hexafluoropropylene) [P(VDF-HFP)], not only in the UV-VIS region but also in the near and mid-infrared region. The copolymer used was obtained by randomly adding 10% molar of [CF2- CF-CF3] monomers in the [CH2-CF2]n main chain of PVDF homopolymer. Preliminary results have shown that the irradiated copolymer has characteristic absorption bands originated by irradiation in the FTIR spectrum. It was found that the 1852 cm{sup -1} band, associated with C = O bonds, have a linear correlation with the absorbed dose for doses ranging from 10 to 750 kGy. The absorption band at 1729 cm{sup -1}, associated to chain oxidation (C = O), has shown a similar behavior and can be used to measure doses from 100 to 1000 kGy. These results indicate that the FTIR absorption bands of gamma irradiated P (VDF-HFP) have great potential to be used in high dose dosimetry, without the addition of dyes. (author)

Iron oxide-based conjugates for cancer theragnostics

Science.gov (United States)

Phuc Nguyen, Xuan; Tran, Dai Lam; Thu Ha, Phuong; Pham, Hong Nam; Trang Mai, Thu; Linh Pham, Hoai; Le, Van Hong; Do, Hung Manh; Bich Hoa Phan, Thi; Giang Pham, Thi Ha; Nguyen, Dac Tu; Nhung Hoang, Thi My; Lam, Khanh; Quy Nguyen, Thi

2012-09-01

In this paper we first summarize our recent research on fabrication and structure characterization of conjugates of Fe3O4 nanoparticles (MNPs) encapsulated by several organic materials such as oleic acid (OL), starch (ST), dextran (D), chitosan (CS), O-carboxymethyl chitosan (OCMCS) and the copolymer of poly(styrene-co-acrylic acid (St-co-AA)). The ferrofluids stability and toxicity were also considered. The magnetic inductive heating (MIH) curves were measured using a set up with an alternating (ac) magnetic field of strength of 40-100 Oe and frequency of 180-240 kHz. We then present new results dealing with attempting to apply the MNP/copolymer ferrofluid for treatment of Sarcoma 180 tumor. In vitro as well as ex vivo MIH experiments were carried out as preparation steps in order to estimate the proper conditions for the in vivo MIH experiment. As for the latter, we have successfully carried out the treatment of solid tumor of size around 6 × 6 mm inoculated on Swiss mice with use of a dose of 0.3-0.4 mg ml-1 ferrofluid injected subcutaneously into the tumor and field-irradiated for 30 min. Two groups of treated mice recovered in three weeks from MIH treatment three times during the first week. We finally show that curcumin loaded MNP-based conjugates showed themselves to be a potential agent for application as a bimodal contrast enhancer of magnetic resonance imaging (MRI) and fluorescence imaging. Additionally, in vitro and ex vivo studies by these two techniques evidenced that macrophage is capable of uptake and tends to carry the MNPs into a tumor.

Iron oxide-based conjugates for cancer theragnostics

International Nuclear Information System (INIS)

Nguyen, Xuan Phuc; Tran, Dai Lam; Ha, Phuong Thu; Pham, Hong Nam; Mai, Thu Trang; Pham, Hoai Linh; Le, Van Hong; Do, Hung Manh; Hoa Phan, Thi Bich; Giang Pham, Thi Ha; Nguyen, Dac Tu; Nhung Hoang, Thi My; Nguyen, Thi Quy; Lam, Khanh

2012-01-01

In this paper we first summarize our recent research on fabrication and structure characterization of conjugates of Fe 3 O 4 nanoparticles (MNPs) encapsulated by several organic materials such as oleic acid (OL), starch (ST), dextran (D), chitosan (CS), O-carboxymethyl chitosan (OCMCS) and the copolymer of poly(styrene-co-acrylic acid (St-co-AA)). The ferrofluids stability and toxicity were also considered. The magnetic inductive heating (MIH) curves were measured using a set up with an alternating (ac) magnetic field of strength of 40–100 Oe and frequency of 180–240 kHz. We then present new results dealing with attempting to apply the MNP/copolymer ferrofluid for treatment of Sarcoma 180 tumor. In vitro as well as ex vivo MIH experiments were carried out as preparation steps in order to estimate the proper conditions for the in vivo MIH experiment. As for the latter, we have successfully carried out the treatment of solid tumor of size around 6 × 6 mm inoculated on Swiss mice with use of a dose of 0.3–0.4 mg ml −1 ferrofluid injected subcutaneously into the tumor and field-irradiated for 30 min. Two groups of treated mice recovered in three weeks from MIH treatment three times during the first week. We finally show that curcumin loaded MNP-based conjugates showed themselves to be a potential agent for application as a bimodal contrast enhancer of magnetic resonance imaging (MRI) and fluorescence imaging. Additionally, in vitro and ex vivo studies by these two techniques evidenced that macrophage is capable of uptake and tends to carry the MNPs into a tumor. (review)

Silicon containing copolymers

CERN Document Server

Amiri, Sahar; Amiri, Sanam

2014-01-01

Silicones have unique properties including thermal oxidative stability, low temperature flow, high compressibility, low surface tension, hydrophobicity and electric properties. These special properties have encouraged the exploration of alternative synthetic routes of well defined controlled microstructures of silicone copolymers, the subject of this Springer Brief. The authors explore the synthesis and characterization of notable block copolymers. Recent advances in controlled radical polymerization techniques leading to the facile synthesis of well-defined silicon based thermo reversible block copolymers?are described along with atom transfer radical polymerization (ATRP), a technique utilized to develop well-defined functional thermo reversible block copolymers. The brief also focuses on Polyrotaxanes and their great potential as stimulus-responsive materials which produce poly (dimethyl siloxane) (PDMS) based thermo reversible block copolymers.

Synthesis and self-assembly behavior of amphiphilic diblock copolymer dextran-block-poly(ε-caprolactone (DEX-b-PCL in aqueous media

Directory of Open Access Journals (Sweden)

2010-10-01

Full Text Available An amphiphilic diblock copolymer, dextran-block-poly(ε-caprolactone (DEX-b-PCL, with a series of welldefined chain lengths of each block was prepared by conjugating a dextran chain with a PCL block via aza-Michael addition reaction under mild conditions. For the dextran block, samples with relatively uniform molecular weight, 3.5 and 6.0 kDa, were used, and the PCL blocks were prepared via ring-opening polymerization at defined ratios of ε-caprolactone to initiator in order to give copolymers with mass fraction of dextran (fDEX ranging from 0.16 to 0.45. When these copolymers were allowed to self-assemble in aqueous solution, the morphology of assembled aggregates varied as a function of fDEX when characterized by transmission electron microscope (TEM, fluorescence microscope (FM and dynamic laser scattering (DLS. As fDEX decreases gradually from 0.45 to 0.16, the morphology of the copolymer assembly changes from spherical micelles to worm-like micelles and eventually to polymersomes, together with an increase in particle sizes.

Synthesis and in vivo magnetic resonance imaging evaluation of biocompatible branched copolymer nanocontrast agents

Directory of Open Access Journals (Sweden)

Jackson AW

2015-09-01

Full Text Available Alexander W Jackson,1,* Prashant Chandrasekharan,2,* Jian Shi,3 Steven P Rannard,4 Quan Liu,5 Chang-Tong Yang,6 Tao He1,7 1Institute of Chemical and Engineering Sciences (ICES, 2Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, Agency for Science Technology and Research (A* STAR, 3Department of Biological Science, National University of Singapore, Singapore; 4Department of Chemistry, University of Liverpool, Liverpool, United Kingdom; 5School of Chemical and Biomedical Engineering, 6Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore; 7School of Chemistry and Chemical Engineering, HeFei University of Technology, Anhui, People’s Republic of China *These authors contributed equally to this work Abstract: Branched copolymer nanoparticles (Dh =20–35 nm possessing 1,4,7, 10-tetraazacyclododecane-N,N',N",N'"-tetraacetic acid macrocycles within their cores have been synthesized and applied as magnetic resonance imaging (MRI nanosized contrast agents in vivo. These nanoparticles have been generated from novel functional monomers via reversible addition–fragmentation chain transfer polymerization. The process is very robust and synthetically straightforward. Chelation with gadolinium and preliminary in vivo experiments have demonstrated promising characteristics as MRI contrast agents with prolonged blood retention time, good biocompatibility, and an intravascular distribution. The ability of these nanoparticles to perfuse and passively target tumor cells through the enhanced permeability and retention effect is also demonstrated. These novel highly functional nanoparticle platforms have succinimidyl ester-activated benzoate functionalities within their corona, which make them suitable for future peptide conjugation and subsequent active cell-targeted MRI or the conjugation of fluorophores for bimodal imaging. We have also demonstrated that these branched copolymer nanoparticles are able to noncovalently

Exploring the origin of high optical absorption in conjugated polymers

KAUST Repository

Vezie, Michelle S.; Few, Sheridan; Meager, Iain; Pieridou, Galatia; Dö rling, Bernhard; Ashraf, Raja Shahid; Goñ i, Alejandro R.; Bronstein, Hugo; McCulloch, Iain; Hayes, Sophia C.; Campoy-Quiles, Mariano; Nelson, Jenny

2016-01-01

The specific optical absorption of an organic semiconductor is critical to the performance of organic optoelectronic devices. For example, higher light-harvesting efficiency can lead to higher photocurrent in solar cells that are limited by sub-optimal electrical transport. Here, we compare over 40 conjugated polymers, and find that many different chemical structures share an apparent maximum in their extinction coefficients. However, a diketopyrrolopyrrole-thienothiophene copolymer shows remarkably high optical absorption at relatively low photon energies. By investigating its backbone structure and conformation with measurements and quantum chemical calculations, we find that the high optical absorption can be explained by the high persistence length of the polymer. Accordingly, we demonstrate high absorption in other polymers with high theoretical persistence length. Visible light harvesting may be enhanced in other conjugated polymers through judicious design of the structure.

Exploring the origin of high optical absorption in conjugated polymers

KAUST Repository

Vezie, Michelle S.

2016-05-16

The specific optical absorption of an organic semiconductor is critical to the performance of organic optoelectronic devices. For example, higher light-harvesting efficiency can lead to higher photocurrent in solar cells that are limited by sub-optimal electrical transport. Here, we compare over 40 conjugated polymers, and find that many different chemical structures share an apparent maximum in their extinction coefficients. However, a diketopyrrolopyrrole-thienothiophene copolymer shows remarkably high optical absorption at relatively low photon energies. By investigating its backbone structure and conformation with measurements and quantum chemical calculations, we find that the high optical absorption can be explained by the high persistence length of the polymer. Accordingly, we demonstrate high absorption in other polymers with high theoretical persistence length. Visible light harvesting may be enhanced in other conjugated polymers through judicious design of the structure.

Fabrication of multicolor fluorescent polyvinyl alcohol through surface modification with conjugated polymers by oxidative polymerization

Science.gov (United States)

Hai, Thien An Phung; Sugimoto, Ryuichi

2018-06-01

A simple method for the preparation of multicolor polyvinyl alcohol (PVA) by chemical oxidative polymerization is introduced. The PVA surface was successfully modified with conjugated polymers composed of 3-hexylthiophene (3HT) and fluorene (F). The incorporation of the 3HT/F copolymer onto the PVA surface was confirmed by Fourier-transform infrared (FT-IR), ultraviolet-visible (UV-vis), and fluorescence spectroscopies, X-ray diffraction (XRD), as well as thermogravimetric analysis (TGA), contact angle, and field-emission scanning electron microscopy (FE-SEM) coupled with energy dispersive X-ray (EDX) analysis. Different 3HT/F ratios on the PVA surface result in optical properties that include multicolor-emission and absorption behavior. The color of the resultant (3HT/F)-g-PVA shifted from red to blue, and the quantum yield increased with increasing F content. The surface hydrophobicity of the modified PVA increased significantly through grafting with the conjugated polymers, with the water contact angle increasing by 30° compared to pristine PVA. The PVA XRD peaks were less intense following surface modification. Thermogravimetric analyses reveal that the thermal stability of the PVA decreases as a result of grafting with the 3HT/F copolymers.

PANI Branches onto Donor-Acceptor Copolymers: Synthesis, Characterization and Electroluminescent Properties of New 2D-Materials

Directory of Open Access Journals (Sweden)

Ignacio A. Jessop

2018-05-01

Full Text Available A new series of two-dimensional statistical conjugated polymers based on aniline and 9,9-dihexylfluorene as donor units and benzo- or naphtho-quinoxaline/thiadiazole derivatives as acceptor moieties, possessing PANI segments as side chains, were designed and synthesized. To investigate the effects of the perpendicular PANI branches on the properties of the main chain, the optical, electrochemical, morphological and electroluminescence properties were studied. The 2D materials tend to possess lower molecular weights and to absorb and to emit light red-shifted compared to the trunk 1D-polymers, in the yellow-red region of the visible spectrum. The 1D- and 2D-conjugated polymers present optical band gaps ranging from 2.15–2.55 eV, HOMO energy levels between −5.37 and −5.60 eV and LUMO energy levels between −3.02 and −3.29 eV. OLED devices based on these copolymers were fabricated. Although the performances were far from optimal due to the high turn-on voltages for which electroluminescence phenomena occur, a maximum luminescence of 55,100 cd/m2 together with a current density of 65 mA/cm2 at 18.5 V were recorded for a 2D-copolymer, PAFC6TBQ-PANI.

Poly(Acrylic Acid-b-Styrene) Amphiphilic Multiblock Copolymers as Building Blocks for the Assembly of Discrete Nanoparticles

Science.gov (United States)

Greene, Anna C.; Zhu, Jiahua; Pochan, Darrin J.; Jia, Xinqiao; Kiick, Kristi L.

2011-01-01

In order to expand the utility of current polymeric micellar systems, we have developed amphiphilic multiblock copolymers containing alternating blocks of poly(acrylic acid) and poly(styrene). Heterotelechelic poly(tert-butyl acrylate-b-styrene) diblock copolymers containing an α-alkyne and an ω-azide were synthesized by atom transfer radical polymerization (ATRP), allowing control over the molecular weight while maintaining narrow polydispersity indices. The multiblock copolymers were constructed by copper-catalyzed azide-alkyne cycloaddition of azide-alkyne end functional diblock copolymers which were then characterized by 1H NMR, FT-IR and SEC. The tert-butyl moieties of the poly(tert-butyl acrylate-b-styrene) multiblock copolymers were easily removed to form the poly(acrylic acid-b-styrene) multiblock copolymer ((PAA-PS)9), which contained up to 9 diblock repeats. The amphiphilic multiblock (PAA-PS)9 (Mn = 73.3 kg/mol) was self-assembled by dissolution into tetrahydrofuran and extensive dialysis against deionized water for 4 days. The critical micelle concentration (CMC) for (PAA-PS)9 was determined by fluorescence spectroscopy using pyrene as a fluorescent probe and was found to be very low at 2 × 10-4 mg/mL. The (PAA-PS)9 multiblock was also analyzed by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The hydrodynamic diameter of the particles was found to be 11 nm. Discrete spherical particles were observed by TEM with an average particle diameter of 14 nm. The poly(acrylic acid) periphery of the spherical particles should allow for future conjugation of biomolecules. PMID:21552373

Effect of N4+ and C4+ ion beam bombardment on the optical and structural characteristics of ethylene-norbornene copolymer (TOPAS)

International Nuclear Information System (INIS)

Siljegovic, M.; Kacarevic-Popovic, Z.M.; Krkljes, A.N.; Stojanovic, Z.; Jovanovic, Z.M.

2011-01-01

Ion bombardment is a suitable tool to modify the optical properties of polymers. In the present study the effect of ion bombardment on the optical absorption of ethylene-norbornene copolymer (TOPAS) was studied using ultraviolet-visible (UV-Vis) and Raman spectroscopy. Polymer samples were bombarded with 60 keV C 4+ and N 4+ ion beams to various fluences ranging from 1.0 x 10 13 to 1.0 x 10 16 cm -2 . The indirect and direct band gaps have been determined. The values of direct band gaps have been found to be greater than the corresponding values of the indirect band gaps. Activation energy has been investigated as the function of ion fluences. The number of carbon atoms per conjugated length is determined according to modified Tauc's equation. The correlation between the optical band gap, activation energy for optical transition and the number of carbon atoms per conjugated length as well as chemical structure changes induced by ion beams irradiation have been discussed in the case of ethylene-norbornene copolymer.

Peptides, proteins and peptide/protein-polymer conjugates as drug delivery system.

Science.gov (United States)

Mukherjee, Biswajit; Karmakar, Swapna D; Hossain, Chowdhury M; Bhattacharya, Sanchari

2014-01-01

In the last few decades, novel drug delivery strategies have been a big priority to the formulation scientists. Peptides and proteins have drawn a special attention for their wide scope in the area. Serum albumin, transferrin, recom- binant proteins, virus capsids etc. are used as carrier for drug and biomolecules. Conjugates of polymers with proteins have also shown strong potency in the field of drug delivery. Polyethylene glycol is one of the most successful polymers that has been used extensively to develop protein conjugated formulations. Besides, polyvinyl pyrrolidone, polylactic-co- glycolic acid, N-(2-hydroxypropyl) methacrylamide copolymer, polyglutamic acid have also been investigated. In this re- view, we will highlight on the most recent overview of various advantages, limitations and marketed products of proteins, peptides and protein/peptide-polymer conjugates as drug carriers, such products in clinical trials and their various uses in the field of modern drug delivery. Understanding the key features of these materials and the vigorous research in this field will develop new drug formulations that will combat various types of life-threatening diseases.

Hyaluronic Acid Graft Copolymers with Cleavable Arms as Potential Intravitreal Drug Delivery Vehicles.

Science.gov (United States)

Borke, Tina; Najberg, Mathie; Ilina, Polina; Bhattacharya, Madhushree; Urtti, Arto; Tenhu, Heikki; Hietala, Sami

2018-01-01

Treatment of retinal diseases currently demands frequent intravitreal injections due to rapid clearance of the therapeutics. The use of high molecular weight polymers can extend the residence time in the vitreous and prolong the injection intervals. This study reports a water soluble graft copolymer as a potential vehicle for sustained intravitreal drug delivery. The copolymer features a high molecular weight hyaluronic acid (HA) backbone and poly(glyceryl glycerol) (PGG) side chains attached via hydrolysable ester linkers. PGG, a polyether with 1,2-diol groups in every repeating unit available for conjugation, serves as a detachable carrier. The influence of synthesis conditions and incubation in physiological media on the molecular weight of HA is studied. The cleavage of the PGG grafts from the HA backbone is quantified and polymer-from-polymer release kinetics are determined. The biocompatibility of the materials is tested in different cell cultures. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bactericidal Specificity and Resistance Profile of Poly(Quaternary Ammonium) Polymers and Protein-Poly(Quaternary Ammonium) Conjugates.

Science.gov (United States)

Ji, Weihang; Koepsel, Richard R; Murata, Hironobu; Zadan, Sawyer; Campbell, Alan S; Russell, Alan J

2017-08-14

Antibacterial polymers are potentially powerful biocides that can destroy bacteria on contact. Debate in the literature has surrounded the mechanism of action of polymeric biocides and the propensity for bacteria to develop resistance to them. There has been particular interest in whether surfaces with covalently coupled polymeric biocides have the same mechanism of action and resistance profile as similar soluble polymeric biocides. We designed and synthesized a series of poly(quaternary ammonium) polymers, with tailorable molecular structures and architectures, to engineer their antibacterial specificity and their ability to delay the development of bacterial resistance. These linear poly(quaternary ammonium) homopolymers and block copolymers, generated using atom transfer radical polymerization, had structure-dependent antibacterial specificity toward Gram positive and negative bacterial species. When single block copolymers contained two polymer segments of differing antibacterial specificity, the polymer combined the specificities of its two components. Nanoparticulate human serum albumin-poly(quaternary ammonium) conjugates of these same polymers, synthesized via "grafting from" atom transfer radical polymerization, were strongly biocidal and also exhibited a marked decrease in the rate of bacterial resistance development relative to linear polymers. These protein-biocide conjugates mimicked the behavior of surface-presented polycationic biocides rather than their nonproteinaceous counterparts.

Olefin–Styrene Copolymers

OpenAIRE

Nunzia Galdi; Antonio Buonerba; Leone Oliva

2016-01-01

In this review are reported some of the most relevant achievements in the chemistry of the ethylene–styrene copolymerization and in the characterization of the copolymer materials. Focus is put on the relationship between the structure of the catalyst and that of the obtained copolymer. On the other hand, the wide variety of copolymer architecture is related to the properties of the material and to the potential utility.

A New Property of Conjugated Polymer PFP: Catalytic Degradation of Methylene Blue Aqueous Solution

Institute of Scientific and Technical Information of China (English)

无

2005-01-01

A new property of conjugated polymer poly(furancarbinol-co-phenol)(PFP) was studied.The target copolymer was used as a catalyst after proper heating treatment. And dye methylene blue (MB) could be fully degraded and largely mineralized on PFP, under natural light or even in dark, in a few minutes. Furthermore, the catalytic activity could be preserved after several runs and the catalyst was readily separated. The effect of calcination temperature was also observed.

HPMA conjugates and immunogenic cancer cell death

Czech Academy of Sciences Publication Activity Database

Kovář, Lubomír; Etrych, Tomáš; Kabešová, Martina; Strohalm, Jiří; Ulbrich, Karel; Říhová, Blanka

2009-01-01

Roč. 39, - (2009), s. 523-523 ISSN 0014-2980. [European Congress of Immunology /2./. 13.09.2009-16.09.2009, Berlin] Institutional research plan: CEZ:AV0Z50200510; CEZ:AV0Z40500505 Keywords : doxorubicin * tumor Subject RIV: EC - Immunology

A tumor-targeted polymer theranostics platform for positron emission tomography and fluorescence imaging

Czech Academy of Sciences Publication Activity Database

Koziolová, Eva; Goel, S.; Chytil, Petr; Janoušková, Olga; Barnhart, T. E.; Cai, W.; Etrych, Tomáš

2017-01-01

Roč. 9, č. 30 (2017), s. 10906-10918 ISSN 2040-3364 R&D Projects: GA ČR(CZ) GA15-02986S; GA MZd(CZ) NV16-28594A; GA MŠk(CZ) LO1507 Institutional support: RVO:61389013 Keywords : N-(2-hydroxypropyl)methacrylamide (HPMA) copolymers * positron emission tomography ( PET ) * fluorescence imaging Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 7.367, year: 2016

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

Photoluminescence and solid state properties of rigid pi- conjugated polymers with applications to LED: Alkyl- substituted p-phenyleneethynylene polymers and triblock copolymers

Science.gov (United States)

Huang, Wen-Yao

A series of substituted poly(p-phenyleneethynylene)s, PPE, were synthesized by alkyne metathesis. The substituents dibutyl (a), dioctyl (b), ditetradecyl (c), di-2-ethylhexyl (d) and di-2-cyclohexylethyl; (e)were placed on the 2,5 positions of the phenyl rings. X-ray diffraction studies indicated that the main chains of each polymer were arranged in regular, layered arrays. Liquid crystalline structures were observed by polarized optical microscopy in PPE 4b, 4c and 4d. The temperatures of isotropization of the liquid crystalline structures coincided with the disordering temperatures determined by differential scanning calorimetry. The UV absorption spectra showed a gradual blue shift of the λmax for all these polymers, suggesting a decrease in the electronic delocalization along the chain as the size and geometry of the side group changed. The photoluminescence spectra in dilute toluene solutions are consistent with vibronic coupling and emission from localized excited states. The emission spectra of thin films show characteristics typical of excimer or aggregate formation in the solid state. Lastly, an improved method of molecular weight determination by end group analysis was devised. Molecular organization and orientation in thin films (~100 nm) of a triblock copolymer, PPEPEG, was studied. The morphology of the thin film can be visualized as consisting of PMMA as the major phase in which domains of vertically oriented triblock copolymers are dispersed with PEG groups facing the air-film interface. The molecular and supramolecular structure of a series of well-defined fully conjugated poly(2,5- diakyl-p-phenyleneethynylene)s, PPE, in toluene has been studied in the sol state and in the gel state by surface tension and photoluminescence measurements. Poly (2,6[4- phenyl quinoline]), I, and poly (2,6[p-phenylene] 4- phenyl quinoline), II, were synthesized by the self- condensation of 5-acetyl-2-aminobezophenone and 4-amino- 4 '-acetyl-3-benzoyl biphenyl

Rationally Engineering Phototherapy Modules of Eosin-Conjugated Responsive Polymeric Nanocarriers via Intracellular Endocytic pH Gradients.

Science.gov (United States)

Liu, Guhuan; Hu, Jinming; Zhang, Guoying; Liu, Shiyong

2015-07-15

Spatiotemporal switching of respective phototherapy modes at the cellular level with minimum side effects and high therapeutic efficacy is a major challenge for cancer phototherapy. Herein we demonstrate how to address this issue by employing photosensitizer-conjugated pH-responsive block copolymers in combination with intracellular endocytic pH gradients. At neutral pH corresponding to extracellular and cytosol milieu, the copolymers self-assemble into micelles with prominently quenched fluorescence emission and low (1)O2 generation capability, favoring a highly efficient photothermal module. Under mildly acidic pH associated with endolysosomes, protonation-triggered micelle-to-unimer transition results in recovered emission and enhanced photodynamic (1)O2 efficiency, which synergistically actuates release of encapsulated drugs, endosomal escape, and photochemical internalization processes.

Blends of Styrene-Butadiene-Styrene Triblock Copolymer with Random Styrene-Maleic Anhydride Copolymers

NARCIS (Netherlands)

Piccini, Maria Teresa; Ruggeri, Giacomo; Passaglia, Elisa; Picchioni, Francesco; Aglietto, Mauro

2002-01-01

Blends of styrene-butadiene-styrene triblock copolymer (SBS) with random styrene-maleic anhydride copolymers (PS-co-MA), having different MA content, were prepared in a Brabender Plastigraph mixer. The presence of polystyrene (PS) blocks in the SBS copolymer and the high styrene content (93 and 86

Main-chain supramolecular block copolymers.

Science.gov (United States)

Yang, Si Kyung; Ambade, Ashootosh V; Weck, Marcus

2011-01-01

Block copolymers are key building blocks for a variety of applications ranging from electronic devices to drug delivery. The material properties of block copolymers can be tuned and potentially improved by introducing noncovalent interactions in place of covalent linkages between polymeric blocks resulting in the formation of supramolecular block copolymers. Such materials combine the microphase separation behavior inherent to block copolymers with the responsiveness of supramolecular materials thereby affording dynamic and reversible materials. This tutorial review covers recent advances in main-chain supramolecular block copolymers and describes the design principles, synthetic approaches, advantages, and potential applications.

Amphiphilic graft copolymer based on poly(styrene-co-maleic anhydride) with low molecular weight polyethylenimine for efficient gene delivery

Science.gov (United States)

Duan, Xiaopin; Xiao, Jisheng; Yin, Qi; Zhang, Zhiwen; Mao, Shirui; Li, Yaping

2012-01-01

Background and methods A new amphiphilic comb-shaped copolymer (SP) was synthesized by conjugating poly(styrene-co-maleic anhydride) with low molecular weight polyethyleneimine for gene delivery. Fourier transform infrared spectrum, 1H nuclear magnetic resonance, and gel permeation chromatography were used to characterize the graft copolymer. Results The buffering capability of SP was similar to that of polyethyleneimine within the endosomal pH range. The copolymer could condense DNA effectively to form complexes with a positive charge (13–30 mV) and a small particle size (130–200 nm) at N/P ratios between 5 and 20, and protect DNA from degradation by DNase I. In addition, SP showed much lower cytotoxicity than polyethyleneimine 25,000. Importantly, the gene transfection activity and cellular uptake of SP-DNA complexes were all markedly higher than that of complexes of polyethyleneimine 25,000 and DNA in MCF-7 and MCF-7/ADR cell lines. Conclusion This work highlights the promise of SP as a safe and efficient synthetic vector for DNA delivery. PMID:23028224

Probing the Relation Between Charge Transport and Supramolecular Organization Down to Ångström Resolution in a Benzothiadiazole‐Cyclopentadithiophene Copolymer

DEFF Research Database (Denmark)

Niedzialek, Dorota; Lemaur, Vincent; Dudenko, Dmytro

2013-01-01

Molecular modeling shows that longitudinal displacement of the backbones by a couple of ångströms has a profound impact on the electronic coupling mediating charge transport in a conjugated copolymer. These changes can be probed by monitoring the calculated X-ray scattering patterns and NMR chemi...... chemical shifts as a function of sliding of the polymer chains and comparing them to experiment....

Improved tumor-specific drug accumulation by polymer therapeutics with pH-sensitive drug release overcomes chemotherapy resistance

Czech Academy of Sciences Publication Activity Database

Heinrich, A. K.; Lucas, H.; Schindler, Lucie; Chytil, Petr; Etrych, Tomáš; Mäder, K.; Mueller, T.

2016-01-01

Roč. 15, č. 5 (2016), s. 998-1007 ISSN 1535-7163 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0109; GA ČR(CZ) GA15-02986S; GA ČR(CZ) GCP207/12/J030; GA ČR(CZ) GA14-12742S Institutional support: RVO:61389013 Keywords : HPMA copolymers * doxorubicin * pH-sensitivity Subject RIV: CD - Macromolecular Chemistry Impact factor: 5.764, year: 2016

Polyaspartamide-Polylactide Graft Copolymers with Tunable Properties for the Realization of Fluorescent Nanoparticles for Imaging.

Science.gov (United States)

Craparo, Emanuela Fabiola; Porsio, Barbara; Mauro, Nicolò; Giammona, Gaetano; Cavallaro, Gennara

2015-08-01

Here, the synthesis and the characterization of novel amphiphilic graft copolymers with tunable properties, useful in obtaining polymeric fluorescent nanoparticles for application in imaging, are described. These copolymers are obtained by chemical conjugation of rhodamine B (RhB) moieties, polylactic acid (PLA), and O-(2-aminoethyl)-O'-methyl poly(ethylene glycol) (PEG) on α,β-poly(N-2-hydroxyethyl)-D,L-aspartamide (PHEA). In particular, PHEA is first functionalized with RhB to obtain PHEA-RhB with a derivatization degree in RhB (DDRhB ) equal to 0.55 mol%. By varying the reaction conditions, different amounts of PLA are grafted on PHEA-RhB to obtain PHEA-RhB-PLA with DDPLA equal to 1.9, 4.0, and 6.2 mol%. Then, PEG chains are grafted on PHEA-RhB-PLA derivatives to obtain PHEA-RhB-PLA-PEG graft copolymers. The preparation of polymeric fluorescent nanoparticles with tunable properties and spherical shape is described by using PHEA-RhB-PLA-PEG with DD in PLA and PEG equal to 4.0 and 4.9 mol%, by following easily scaling up processes, such as emulsion-solvent evaporation and high pressure homogenization (HPH)-solvent evaporation techniques. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Enhanced cellular uptake and phototoxicity of Verteporfin-conjugated gold nanoparticles as theranostic nanocarriers for targeted photodynamic therapy and imaging of cancers

Energy Technology Data Exchange (ETDEWEB)

Zhao, Linlin [Tianjin Key Laboratory for Photoelectric Materials and Devices, School of Materials Science & Engineering, Tianjin University of Technology, Tianjin 300384 (China); Graduate School of Energy Science and Technology, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Kim, Tae-Hyun; Kim, Hae-Won [Department of Nanobiomedical Science, Dankook University Graduate School, Cheonan 330-714 (Korea, Republic of); Institute of Tissue Regeneration Engineering (ITREN) & College of Dentistry, Dankook University, Cheonan 330-714 (Korea, Republic of); Ahn, Jin-Chul [Department of Biomedical Science, College of Medicine, Dankook University, Cheonan, 330-714 (Korea, Republic of); Kim, So Yeon, E-mail: kimsy@cnu.ac.kr [Graduate School of Energy Science and Technology, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Department of Chemical Engineering Education, College of Education, Chungnam National University, Daejeon 305-764 (Korea, Republic of)

2016-10-01

Activatable theranostics with the capacity to respond to a given stimulus have recently been intensively explored to develop more specific, individualized therapies for various diseases, and to combine diagnostic and therapeutic capabilities into a single agent. In this work, we designed tumor-targeting ligand-conjugated block copolymer-gold nanoparticle (AuNP) conjugates as multifunctional nanocarriers of the hydrophobic photosensitizer (PS), verteporfin (Verte), for simultaneous photodynamic therapy and imaging of cancers. Folic acid (FA)-conjugated block copolymers composed of polyethylene glycol (PEG) and poly-β-benzyl-L-aspartate (PBLA) were attached to citrate-stabilized AuNPs through a bidentate dihydrolipoic acid (DHLA) linker. The resulting AuNP conjugates (FA-PEG-P(Asp-Hyd)-DHLA-AuNPs) were significantly more stable than unmodified AuNPs, and their optical properties were not affected by pH. The hydrophobic PS, Verte, was covalently incorporated onto the surfaces of the AuNP conjugates through a pH-sensitive linkage, which increased the water solubility of Verte from < 1 μg/ml to > 2000 μg/ml. The size of FA-PEG-P(Asp-Hyd)-DHLA-AuNPs-Verte as determined by light-scattering measurements was about 110.3 nm, and FE-SEM and FE-TEM images showed that these nanoparticles were spherical and showed adequate dispersivity after modification. In particular, an in vitro cell study revealed high intracellular uptake of FA-PEG-P(Asp-Hyd)-DHLA-AuNPs-Verte (about 98.62%) and marked phototoxicity after laser irradiation compared with free Verte. These results suggest that FA-PEG-P(Asp-Hyd)-DHLA-AuNPs-Verte has great potential as an effective nanocarrier for dual imaging and photodynamic therapy. - Highlights: • We designed theranostic nanocarriers for photodynamic therapy and imaging of cancers. • AuNP conjugates had a spherical shape and a narrow size distribution with a mean diameter of 110.3 nm. • Cellular uptake of free Verte was 18.86%, whereas that of Au

Metallo-supramolecular block copolymer micelles

NARCIS (Netherlands)

Gohy, J.M.W.

2009-01-01

Supramolecular copolymers have become of increasing interest in recent years in the search for new materials with tunable properties. In particular, metallo-supramolecular block copolymers in which metal-ligand complexes are introduced in block copolymer architectures, have known important progress,

Strong adsorbability of mercury ions on aniline/sulfoanisidine copolymer nanosorbents.

Science.gov (United States)

Li, Xin-Gui; Feng, Hao; Huang, Mei-Rong

2009-01-01

The highest Hg-ion adsorbance so far, namely up to 2063 mg g(-1), has been achieved by poly(aniline-co-5-sulfo-2-anisidine) nanosorbents. Sorption of Hg ions occurs mainly by redox and chelation mechanisms (see scheme), but also by ion exchange and physisorption.Poly(aniline (AN)-co-5-sulfo-2-anisidine (SA)) nanoparticles were synthesized by chemical oxidative copolymerization of AN and SA monomers, and their extremely strong adsorption of mercury ions in aqueous solution was demonstrated. The reactivity ratios of AN and SA comonomers were found to be 2.05 and 0.02, respectively. While AN monomer tends to homopolymerize, SA monomer tends to copolymerize with AN monomer because of the great steric hindrance and electron-attracting effect of the sulfo groups, despite the effect of conjugation of the methoxyl group with the benzene ring. The effects of initial mercury(II) concentration, sorption time, sorption temperature, ultrasonic treatment, and sorbent dosage on mercury-ion sorption onto AN/SA (50/50) copolymer nanoparticles with a number-average diameter of around 120 nm were significantly optimized. The results show that the maximum Hg-ion sorption capacity on the particulate nanosorbents can even reach 2063 mg of Hg per gram of sorbent, which would be the highest Hg-ion adsorbance so far. The sorption data fit to the Langmuir isotherm, and the process obeys pseudo-second-order kinetics. The IR and UV/Vis spectral data of the Hg-loaded copolymer particles suggest that some mercury(II) was directly reduced by the copolymer to mercury(I) and even mercury(0). A mechanism of sorption between the particles and Hg ions in aqueous solution is proposed, and a physical/ion exchange/chelation/redox sorption ratio of around 2/3/45/50 was found. Copolymer nanoparticles may be one of the most powerful and cost-effective sorbents of mercury ions, with a wide range of potential applications for the efficient removal and even recovery of the mercury ions from aqueous solution.

Organic Diode Rectifiers Based on a High-Performance Conjugated Polymer for a Near-Field Energy-Harvesting Circuit.

Science.gov (United States)

Higgins, Stuart G; Agostinelli, Tiziano; Markham, Steve; Whiteman, Robert; Sirringhaus, Henning

2017-12-01

Organic diodes manufactured on a plastic substrate capable of rectifying a high-frequency radio-frequency identification signal (13.56 MHz), with sufficient power to operate an interactive smart tag, are reported. A high-performance conjugated semiconductor (an indacenodithiophene-benzothiadiazole copolymer) is combined with a carefully optimized architecture to satisfy the electrical requirements for an organic-semiconductor-based logic chip. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Distribution of short block copolymer chains in Binary Blends of Block Copolymers Having Hydrogen Bonding

Science.gov (United States)

Kwak, Jongheon; Han, Sunghyun; Kim, Jin Kon

2014-03-01

A binary mixture of two block copolymers whose blocks are capable of forming the hydrogen bonding allows one to obtain various microdomains that could not be expected for neat block copolymer. For instance, the binary blend of symmetric polystyrene-block-poly(2-vinylpyridine) copolymer (PS-b-P2VP) and polystyrene-block-polyhydroxystyrene copolymer (PS-b-PHS) blends where the hydrogen bonding occurred between P2VP and PHS showed hexagonally packed (HEX) cylindrical and body centered cubic (BCC) spherical microdomains. To know the exact location of short block copolymer chains at the interface, we synthesized deuterated polystyrene-block-polyhydroxystyrene copolymer (dPS-b-PHS) and prepared a binary mixture with PS-b-P2VP. We investigate, via small angle X-ray scattering (SAXS) and neutron reflectivity (NR), the exact location of shorter dPS block chain near the interface of the microdomains.

Mercapturic Acids Derived from the Toxicants Acrolein and Crotonaldehyde in the Urine of Cigarette Smokers from Five Ethnic Groups with Differing Risks for Lung Cancer.

Directory of Open Access Journals (Sweden)

Sungshim L Park

Full Text Available The Multiethnic Cohort epidemiology study has clearly demonstrated that, compared to Whites and for the same number of cigarettes smoked, African Americans and Native Hawaiians have a higher risk for lung cancer whereas Latinos and Japanese Americans have a lower risk. Acrolein and crotonaldehyde are two important constituents of cigarette smoke which have well documented toxic effects and could play a role in lung cancer etiology. Their urinary metabolites 3-hydroxypropylmercapturic acid (3-HPMA and 3-hydroxy-1-methylpropylmercapturic acid (HMPMA, respectively, are validated biomarkers of acrolein and crotonaldehyde exposure. We quantified levels of 3-HPMA and HMPMA in the urine of more than 2200 smokers from these five ethnic groups, and also carried out a genome wide association study using blood samples from these subjects. After adjusting for age, sex, creatinine, and total nicotine equivalents, geometric mean levels of 3-HPMA and HMPMA were significantly different in the five groups (P < 0.0001. Native Hawaiians had the highest and Latinos the lowest geometric mean levels of both 3-HPMA and HMPMA. Levels of 3-HPMA and HMPMA were 3787 and 2759 pmol/ml urine, respectively, in Native Hawaiians and 1720 and 2210 pmol/ml urine in Latinos. These results suggest that acrolein and crotonaldehyde may be involved in lung cancer etiology, and that their divergent levels may partially explain the differing risks of Native Hawaiian and Latino smokers. No strong signals were associated with 3-HPMA in the genome wide association study, suggesting that formation of the glutathione conjugate of acrolein is mainly non-enzymatic, while the top significant association with HMPMA was located on chromosome 12 near the TBX3 gene, but its relationship to HMPMA excretion is not clear.

Effect of temperature and ph on the drug release rate from a polymer conjugate system

International Nuclear Information System (INIS)

Kenawy, E.; Abdel-Hay, F.I.; El-Newehy, M.H.; Ottenbrite, R.M.

2005-01-01

Hydroximide and A-methylhydroxamic acid of poly(ethylene-altmaleic anhydride) (average MW 100-500 k) were used as a carrier for a new drug delivery system. The synthesis of the hydroximide and N methylhydroxamic acid of poly(ethylene-alt-maleic anhydride) were carried out by chemical modification of poly(ethylene-alt-maleic anhydride) with hydroxylamine and N-methyl hydroxylamine, respectively, in N,N- dimethylformamide at room temperature to yield water soluble copolymer. Ketoprofen was reacted with hydroximide and N-methylhydroxamic acid derivatives of poly(ethylene-alt-maleic anhydride) using dicyclohexylcarbodiimide as condensation agent at -5 degree C to yield water insoluble ketoprofen conjugates. All products were characterized by elemental analysis, FTIR and 1HNMR spectra. The in-vitro ketoprofen release was carried out by UV spectrophotometer at max =260 nm. The results demonstrated the effectiveness of hydroximide and N-methylhydroxamic acid of polyethylene-alt-maleic anhydride) as a drug delivery system. The release rates were studied at various ph and temperatures. The copolymer-drug adducts released the drug very slowly at the low ph found in the stomach thus protecting the drug from the action of high concentrations of digestive acids. These results showed the usefulness of hydroxamic acid polymer-drug conjugates as a new drug delivery system for drugs to be targeted to sites in the GI system

Solvent-resistant organic transistors and thermally stable organic photovoltaics based on cross-linkable conjugated polymers

KAUST Repository

Kim, Hyeongjun

2012-01-10

Conjugated polymers, in general, are unstable when exposed to air, solvent, or thermal treatment, and these challenges limit their practical applications. Therefore, it is of great importance to develop new materials or methodologies that can enable organic electronics with air stability, solvent resistance, and thermal stability. Herein, we have developed a simple but powerful approach to achieve solvent-resistant and thermally stable organic electronic devices with a remarkably improved air stability, by introducing an azide cross-linkable group into a conjugated polymer. To demonstrate this concept, we have synthesized polythiophene with azide groups attached to end of the alkyl chain (P3HT-azide). Photo-cross-linking of P3HT-azide copolymers dramatically improves the solvent resistance of the active layer without disrupting the molecular ordering and charge transport. This is the first demonstration of solvent-resistant organic transistors. Furthermore, the bulk-heterojunction organic photovoltaics (BHJ OPVs) containing P3HT-azide copolymers show an average efficiency higher than 3.3% after 40 h annealing at an elevated temperature of 150 °C, which represents one of the most thermally stable OPV devices reported to date. This enhanced stability is due to an in situ compatibilizer that forms at the P3HT/PCBM interface and suppresses macrophase separation. Our approach paves a way toward organic electronics with robust and stable operations. © 2011 American Chemical Society.

Pronounced Side Chain Effects in Triple Bond-Conjugated Polymers Containing Naphthalene Diimides for n-Channel Organic Field-Effect Transistors

KAUST Repository

Nam, Sungho

2018-03-23

Three triple bond-conjugated naphthalene diimide (NDI) copolymers, poly{[N,N′-bis(2-R1)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-[(2,5-bis(2-R2)-1,4-phenylene)bis(ethyn-2,1-diyl)]} (PNDIR1-R2), were synthesized via Sonogashira coupling polymerization with varying alkyl side chains at the nitrogen atoms of the imide ring and 2,5-positions of the 1,4-diethynylbenzene moiety. Considering their identical polymer backbone structures, the side chains were found to have a strong influence on the surface morphology/nanostructure, thus playing a critical role in charge-transporting properties of the three NDI-based copolymers. Among the polymers, the one with an octyldodecyl (OD) chain at the nitrogen atoms of imide ring and a hexadecyloxy (HO) chain at the 2,5-positions of 1,4-diethynylbenzene, P(NDIOD-HO), exhibited the highest electron mobility of 0.016 cm2 V–1 s–1, as compared to NDI-based copolymers with an ethylhexyl chain at the 2,5-positions of 1,4-diethynylbenzene. The enhanced charge mobility in the P(NDIOD-HO) layers is attributed to the well-aligned nano-fiber-like surface morphology and highly ordered packing structure with a dominant edge-on orientation, thus enabling efficient in-plane charge transport. Our results on the molecular structure–charge transport property relationship in these materials may provide an insight into novel design of n-type conjugated polymers for applications in the organic electronics of the future.

Synthesis of a conjugated pyrrolopyridazinedione–benzodithiophene (PPD–BDT) copolymer and its application in organic and hybrid solar cells

KAUST Repository

Knall, Astrid-Caroline; Jones, Andrew O. F.; Kunert, Birgit; Resel, Roland; Reishofer, David; Zach, Peter W.; Kirkus, Mindaugas; McCulloch, Iain; Rath, Thomas

2017-01-01

-coupling polycondensation. The resulting PPD–BDT copolymer revealed an optical bandgap of 1.8 eV and good processability from chlorobenzene solutions. In an organic solar cell in combination with PC70BM, the polymer led to a power conversion efficiency of 4.5%. Moreover

Effect of furan π-bridge on the photovoltaic performance of D-A copolymers based on bi(alkylthio-thienyl)benzodithiophene and fluorobenzotriazole

Institute of Scientific and Technical Information of China (English)

Tinghai Yan; Haijun Bin; Yankang Yang; Lingwei Xue; Zhi-Guo Zhang; Yongfang Li

2017-01-01

The medium band gap donor-acceptor（D-A） copolymer J61 based on bi（alkylthio-thienyl）benzodithiophene as donor unit and fluorobenzotriazole as acceptor unit and thiophene as π-bridge has demonstrated excellent photovoltaic performance as donor material in nonfullerene polymer solar cells（PSCs） with narrow bandgap n-type organic semiconductor ITIC as acceptor.For studying the effect of π-bridges on the photovoltaic performance of the D-A copolymers,here we synthesized a new D-A copolymer J61-F based on the same donor and acceptor units as J61 but with furan π-bridges instead of thiophene.J61-F possesses a deeper the highest occupied molecular orbital（HOMO） level at-5.45 eV in comparison with that（-5.32 eV） of J61.The non-fullerene PSCs based on J61-F:ITIC exhibited a maximum power conversion efficiency（PCE） of 8.24%with a higher open-circuit voltage(Voc) of 0.95 V,which is benefitted from the lower-lying HOMO energy level of J61-F donor material.The results indicate that main chain engineering by changing π-bridges is another effective way to tune the electronic energy levels of the conjugated D-A copolymers for the application as donor materials in non-fullerene PSCs.

Effect of furan n-bridge on the photovoltaic performance of D-A copolymers based on bi(alkylthio-thienyl)benzodithiophene and fluorobenzotriazole

Institute of Scientific and Technical Information of China (English)

Tinghai Yan; Haijun Bin; Yankang Yang; Lingwei Xue; Zhi-Guo Zhang; Yongfang Li

2017-01-01

The medium band gap donor-acceptor (D-A) copolymer J61 based on bi(alkylthio-thienyl)benzodithiophene as donor unit and fluorobenzotriazole as acceptor unit and thiophene as π-bridge has demonstrated excellent photovoltaic performance as donor material in nonfullerene polymer solar cells (PSCs) with narrow bandgap n-type organic semiconductor ITIC as acceptor.For studying the effect of π-bridges on the photovoltaic performance of the D-A copolymers,here we synthesized a new D-A copolymer J61-F based on the same donor and acceptor units as J61 but with furan π-bridges instead ofthiophene.J61-F possesses a deeper the highest occupied molecular orbital (HOMO) level at-5.45 eV in comparison with that (-5.32 eV) of J61.The non-fullerene PSCs based on J61-F:ITIC exhibited a maximum power conversion efficiency (PCE) of 8.24％ with a higher open-circuit voltage (Voo) of 0.95 V,which is benefitted from the lower-lying HOMO energy level of J61-F donor material.The results indicate that main chain engineering by changing π-bridges is another effective way to tune the electronic energy levels of the conjugated D-A copolymers for the application as donor materials in non-fullerene PSCs.

The radiation crosslinking of ethylene copolymers

International Nuclear Information System (INIS)

Burns, N.M.

1979-01-01

The enhanced radiation crosslinking tendency of ethylene-vinyl acetate and ethylene-ethyl acrylate copolymers over ethylene homopolymer is proportional to the comonomer content. This is caused by an increase in the amorphous polymer content and by structure-related factors. The copolymers crosslink by a random process that for ethylene-vinyl acetate copolymer involves some crosslinking through the acetoxy group of the comonomer. While knowledge of the process for the crosslinking of ethylene-ethyl acrylate copolymer is less certain, it is currently believed to occur primarily at the branch point on the polymer backbone. Data relating comonomer content and the molecular weight of the copolymers to the radiation crosslinking levels realized were developed to aid in resin selection by the formulator. Triallyl cyanurate cure accelerator was found to be less effective in ethylene-vinyl acetate copolymer than in homopolymer and to have no effect on gel development in ethylene-ethyl acrylate copolymer. (author)

Impact of the Crystallite Orientation Distribution on Exciton Transport in Donor–Acceptor Conjugated Polymers

KAUST Repository

Ayzner, Alexander L.; Mei, Jianguo; Appleton, Anthony; DeLongchamp, Dean; Nardes, Alexandre; Benight, Stephanie; Kopidakis, Nikos; Toney, Michael F.; Bao, Zhenan

2015-01-01

© 2015 American Chemical Society. Conjugated polymers are widely used materials in organic photovoltaic devices. Owing to their extended electronic wave functions, they often form semicrystalline thin films. In this work, we aim to understand whether distribution of crystallographic orientations affects exciton diffusion using a low-band-gap polymer backbone motif that is representative of the donor/acceptor copolymer class. Using the fact that the polymer side chain can tune the dominant crystallographic orientation in the thin film, we have measured the quenching of polymer photoluminescence, and thus the extent of exciton dissociation, as a function of crystal orientation with respect to a quenching substrate. We find that the crystallite orientation distribution has little effect on the average exciton diffusion length. We suggest several possibilities for the lack of correlation between crystallographic texture and exciton transport in semicrystalline conjugated polymer films.

Impact of the Crystallite Orientation Distribution on Exciton Transport in Donor–Acceptor Conjugated Polymers

KAUST Repository

Ayzner, Alexander L.

2015-12-30

© 2015 American Chemical Society. Conjugated polymers are widely used materials in organic photovoltaic devices. Owing to their extended electronic wave functions, they often form semicrystalline thin films. In this work, we aim to understand whether distribution of crystallographic orientations affects exciton diffusion using a low-band-gap polymer backbone motif that is representative of the donor/acceptor copolymer class. Using the fact that the polymer side chain can tune the dominant crystallographic orientation in the thin film, we have measured the quenching of polymer photoluminescence, and thus the extent of exciton dissociation, as a function of crystal orientation with respect to a quenching substrate. We find that the crystallite orientation distribution has little effect on the average exciton diffusion length. We suggest several possibilities for the lack of correlation between crystallographic texture and exciton transport in semicrystalline conjugated polymer films.

Core/Shell Conjugated Polymer/Quantum Dot Composite Nanofibers through Orthogonal Non-Covalent Interactions

Directory of Open Access Journals (Sweden)

Brad W. Watson

2016-11-01

Full Text Available Nanostructuring organic polymers and organic/inorganic hybrid materials and controlling blend morphologies at the molecular level are the prerequisites for modern electronic devices including biological sensors, light emitting diodes, memory devices and solar cells. To achieve all-around high performance, multiple organic and inorganic entities, each designed for specific functions, are commonly incorporated into a single device. Accurate arrangement of these components is a crucial goal in order to achieve the overall synergistic effects. We describe here a facile methodology of nanostructuring conjugated polymers and inorganic quantum dots into well-ordered core/shell composite nanofibers through cooperation of several orthogonal non-covalent interactions including conjugated polymer crystallization, block copolymer self-assembly and coordination interactions. Our methods provide precise control on the spatial arrangements among the various building blocks that are otherwise incompatible with one another, and should find applications in modern organic electronic devices such as solar cells.

Protein Modification with Amphiphilic Block Copoly(2-oxazoline)s as a New Platform for Enhanced Cellular Delivery

KAUST Repository

Tong, Jing; Luxenhofer, Robert; Yi, Xiang; Jordan, Rainer; Kabanov, Alexander V.

2010-01-01

Several homopolymers, random copolymers and block copolymers based on poly(2-oxazoline)s (POx) were synthesized and conjugated to horseradish peroxidase (HRP) using biodegradable and nonbiodegradable linkers. These conjugates were characterized by amino group titration, polyacrylamide gel electrophoresis (PAGE), isoelectric focusing, enzymatic activity assay and conformation analysis. The conjugates contained on average from about one to two polymer chains per enzyme. From 70% to 90% of enzymatic activity was retained in most cases. Circular dichroism (CD) analysis revealed that HRP modification affected the secondary structure of the apoprotein but did not affect the tertiary structure and heme environment. Enhanced cellular uptake was found in the conjugates of two block copolymers using both MDCK cells and Caco-2 cells, but not in the conjugates of random copolymer and homopolymer. Conjugation with a block copolymer of 2-methyl-2-oxazoline and 2-butyl-2-oxazoline led to the highest cellular uptake as compared to other conjugates. Our data indicates that modification with amphiphilic POx has the potential to modulate and enhance cellular delivery of proteins.

Protein Modification with Amphiphilic Block Copoly(2-oxazoline)s as a New Platform for Enhanced Cellular Delivery

KAUST Repository

Tong, Jing

2010-08-02

Several homopolymers, random copolymers and block copolymers based on poly(2-oxazoline)s (POx) were synthesized and conjugated to horseradish peroxidase (HRP) using biodegradable and nonbiodegradable linkers. These conjugates were characterized by amino group titration, polyacrylamide gel electrophoresis (PAGE), isoelectric focusing, enzymatic activity assay and conformation analysis. The conjugates contained on average from about one to two polymer chains per enzyme. From 70% to 90% of enzymatic activity was retained in most cases. Circular dichroism (CD) analysis revealed that HRP modification affected the secondary structure of the apoprotein but did not affect the tertiary structure and heme environment. Enhanced cellular uptake was found in the conjugates of two block copolymers using both MDCK cells and Caco-2 cells, but not in the conjugates of random copolymer and homopolymer. Conjugation with a block copolymer of 2-methyl-2-oxazoline and 2-butyl-2-oxazoline led to the highest cellular uptake as compared to other conjugates. Our data indicates that modification with amphiphilic POx has the potential to modulate and enhance cellular delivery of proteins.

Solvent polarity effects on supramolecular chirality of a polyfluorene-thiophene copolymer.

Science.gov (United States)

Hirahara, Takashi; Yoshizawa-Fujita, Masahiro; Takeoka, Yuko; Rikukawa, Masahiro

2018-06-01

This study demonstrates the supramolecular chirality control of a conjugated polymer via solvent polarity. We designed and synthesized a chiral polyfluorene-thiophene copolymer having two different chiral side chains at the 9-position of the fluorene unit. Chiral cyclic and alkyl ethers with different polarities were selected as the chiral side chains. The sign of the circular dichroism spectra in the visible wavelength region was affected by the solvent system, resulting from the change of supramolecular structure. The estimation of the solubility parameter revealed that the solubility difference of the side chains contributed to the change of the circular dichroism sign, which was also observed in spin-coated films prepared from good solvents having different polarities. © 2018 Wiley Periodicals, Inc.

Radiation resistance of ethylene-styrene copolymers

International Nuclear Information System (INIS)

Matsumoto, Kaoru; Ikeda, Masaaki; Ohki, Yoshimichi; Kusama, Yasuo; Harashige, Masahiro; Yazaki, Fumihiko.

1988-01-01

In this paper, the radiation resistance of ethylene-styrene copolymer, a polymeric resin developed newly by the authors, is reported. Resin examined were five kinds of ethylene-styrene copolymers: three random and two graft copolymers with different styrene contents. Low-density polyethylene was used as a reference. The samples were irradiated by 60 Co γ-rays to total absorbed doses up to 10 MGy. The mechanical properties of the smaples were examined. Infrared spectroscopy, differential scanning calorimetry and X-ray scattering techniques were used to examine the morphology of the samples. The random copolymers are soft and easy to extend, because benzene rings which exisist highly at random hinder the crystallization. As for the radiation resistance, they are highly resistant to γ-rays in the aspects of carbonyl group formation, gel formation, and elongation. Further, they show even better radiation resistance when proper additives were compounded in. The graft copolymers are hard to extend, because they consist of segregated polystyrene and polyethylene regions which are connected with each other. The tensile strength of irradiated graft copolymers does not decrease below that of unirradiated copolymers, up to a total dose of 10 MGy. As a consequence, it can be said that ethylene-styrene copolymers have good radiation resistance owing to the so-called 'sponge' effect of benzene rings. (author)

HPMA Copolymer-Bound Doxorubicin Induces Immunogenic Tumor Cell Death

Czech Academy of Sciences Publication Activity Database

Šírová, Milada; Kabešová, Martina; Kovář, Lubomír; Etrych, Tomáš; Strohalm, Jiří; Ulbrich, Karel; Říhová, Blanka

2013-01-01

Roč. 20, č. 38 (2013), s. 4815-4826 ISSN 0929-8673 R&D Projects: GA ČR GAP301/12/1254 Institutional support: RVO:61388971 ; RVO:61389013 Keywords : Anti-tumor immune response * calreticulin * heat shock proteins Subject RIV: CE - Biochemistry Impact factor: 3.715, year: 2013

Glycan-decorated HPMA copolymers as high-affinity lectin ligands

Czech Academy of Sciences Publication Activity Database

Bojarová, Pavla; Chytil, Petr; Mikulová, Barbora; Bumba, Ladislav; Konefal, Rafal; Pelantová, Helena; Krejzová, Jana; Slámová, Kristýna; Petrásková, Lucie; Kotrchová, Lenka; Cvačka, Josef; Etrych, Tomáš; Křen, Vladimír

2017-01-01

Roč. 8, č. 17 (2017), s. 2647-2658 ISSN 1759-9954 R&D Projects: GA ČR GC15-02578J; GA MZd(CZ) NV16-28594A; GA MŠk(CZ) LD15085; GA MŠk(CZ) LM2015064; GA MŠk(CZ) LO1507 Institutional support: RVO:61388971 ; RVO:61389013 ; RVO:61388963 Keywords : BETA-N-ACETYLHEXOSAMINIDASE * WHEAT-GERM-AGGLUTININ * CLICK CHEMISTRY Subject RIV: CE - Biochemistry; CD - Macromolecular Chemistry (UMCH-V) OBOR OECD: Biochemistry and molecular biology; Polymer science (UMCH-V); Polymer science (UOCHB-X) Impact factor: 5.375, year: 2016

Nanostructuration of self-assembled poly(styrene-b-isoprene-b-styrene) block copolymer thin films in a highly oriented pyrolytic graphite substrate

Energy Technology Data Exchange (ETDEWEB)

Zalakain, Inaki; Ramos, Jose Angel; Fernandez, Raquel; Etxeberria, Haritz; Mondragon, Inaki, E-mail: inaki.mondragon@ehu.e

2011-01-03

Highly oriented pyrolitic graphite (HOPG) is a useful substrate to visualize epitaxial formation due to its crystallographic structure. The morphology of a poly(styrene-b-isoprene-b-styrene) block copolymer thin film on a HOPG substrate was investigated by atomic force microscopy. Block copolymer domains generated a morphology with triangular regularity. This arrangement was induced by the HOPG substrate structure due to van der Waals attraction between the HOPG {pi}-conjugated system and aromatic ring of polystyrene domains. However, increasing the film thickness, the substrate effect on the surface morphology decreased. As a consequence, film surfaces showed the coexistence of different structures such as highly aligned cylinders and perforated lamellae. When film thickness exceeded a threshold value, the substrate did not have effect in the surface arrangements and the surface showed a similar morphology to that existing in bulk.

Molecular Interaction Control in Diblock Copolymer Blends and Multiblock Copolymers with Opposite Phase Behaviors

Science.gov (United States)

Cho, Junhan

2014-03-01

Here we show how to control molecular interactions via mixing AB and AC diblock copolymers, where one copolymer exhibits upper order-disorder transition and the other does lower disorder-order transition. Linear ABC triblock copolymers possessing both barotropic and baroplastic pairs are also taken into account. A recently developed random-phase approximation (RPA) theory and the self-consistent field theory (SCFT) for general compressible mixtures are used to analyze stability criteria and morphologies for the given systems. It is demonstrated that the copolymer systems can yield a variety of phase behaviors in their temperature and pressure dependence upon proper mixing conditions and compositions, which is caused by the delicate force fields generated in the systems. We acknowledge the financial support from National Research Foundation of Korea and Center for Photofunctional Energy Materials.

Overcoming multidrug resistance via simultaneous delivery of cytostatic drug and P-glycoprotein inhibitor to cancer cells by HPMA copolymer conjugate

Czech Academy of Sciences Publication Activity Database

Sivák, Ladislav; Šubr, Vladimír; Tomala, Jakub; Říhová, Blanka; Strohalm, Jiří; Etrych, Tomáš; Kovář, Marek

2017-01-01

Roč. 115, JAN 2017 (2017), s. 65-80 ISSN 0142-9612 R&D Projects: GA ČR(CZ) GAP301/12/1254; GA MŠk(CZ) LQ1604; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61388971 ; RVO:61389013 Keywords : Multidrug resistance * P-glycoprotein * Doxorubicin Subject RIV: EE - Microbiology, Virology; CD - Macromolecular Chemistry (UMCH-V) OBOR OECD: Microbiology; Polymer sci ence (UMCH-V) Impact factor: 8.402, year: 2016

Rapid self-assembly of block copolymers to photonic crystals

Science.gov (United States)

Xia, Yan; Sveinbjornsson, Benjamin R; Grubbs, Robert H; Weitekamp, Raymond; Miyake, Garret M; Atwater, Harry A; Piunova, Victoria; Daeffler, Christopher Scot; Hong, Sung Woo; Gu, Weiyin; Russell, Thomas P.

2016-07-05

The invention provides a class of copolymers having useful properties, including brush block copolymers, wedge-type block copolymers and hybrid wedge and polymer block copolymers. In an embodiment, for example, block copolymers of the invention incorporate chemically different blocks comprising polymer size chain groups and/or wedge groups that significantly inhibit chain entanglement, thereby enhancing molecular self-assembly processes for generating a range of supramolecular structures, such as periodic nanostructures and microstructures. The present invention also provides useful methods of making and using copolymers, including block copolymers.

Lignin poly(lactic acid) copolymers

Energy Technology Data Exchange (ETDEWEB)

Olsson, Johan Vilhelm; Chung, Yi-Lin; Li, Russell Jingxian; Waymouth, Robert; Sattely, Elizabeth; Billington, Sarah; Frank, Curtis W.

2017-02-14

Provided herein are graft co-polymers of lignin and poly(lactic acid) (lignin-g-PLA copolymer), thermoset and thermoplastic polymers including them, methods of preparing these polymers, and articles of manufacture including such polymers.

Electronic Properties and Photovoltaic Performances of a Series of Oligothiophene Copolymers Incorporating Both Thieno[3,2-b]thiophene and 2,1,3-Benzothiadiazole Moieties.

Science.gov (United States)

Biniek, Laure; Chochos, Christos L; Hadziioannou, Georges; Leclerc, Nicolas; Lévêque, Patrick; Heiser, Thomas

2010-04-06

A series of donor-acceptor alternated conjugated copolymers, composed of thiophene, bithiophene, thieno[3,2-b]thiophene, and 2,1,3-benzothiadiazole units and differing from each other by the nature and the number of 3-alkylthiophene in the backbone, have been synthesized by Stille cross-coupling polymerization. The material's optical and electrochemical properties, in solution and in thin films, have been investigated using UV-Visible absorption and cyclic voltammetry. Bulk heterojunction solar cells using blends of the newly synthesized copolymers, as electron donor, and C60-PCBM or C70-PCBM, as electron transporting material, have been elaborated. A maximum power conversion efficiency of 1.8% is achieved with a 1:4 PPBzT(2) -C12:C70-PCBM weight ratio. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Block copolymer membranes for aqueous solution applications

KAUST Repository

Nunes, Suzana Pereira

2016-03-22

Block copolymers are known for their intricate morphology. We review the state of the art of block copolymer membranes and discuss perspectives in this field. The main focus is on pore morphology tuning with a short introduction on non-porous membranes. The two main strategies for pore formation in block copolymer membranes are (i) film casting and selective block sacrifice and (ii) self-assembly and non-solvent induced phase separation (SNIPS). Different fundamental aspects involved in the manufacture of block copolymer membranes are considered, including factors affecting the equilibrium morphology in solid films, self-assembly of copolymer in solutions and macrophase separation by solvent-non-solvent exchange. Different mechanisms are proposed for different depths of the SNIPS membrane. Block copolymer membranes can be prepared with much narrower pore size distribution than homopolymer membranes. Open questions and indications of what we consider the next development steps are finally discussed. They include the synthesis and application of new copolymers and specific functionalization, adding characteristics to respond to stimuli and chemical environment, polymerization-induced phase separation, and the manufacture of organic-inorganic hybrids.

Block copolymer membranes for aqueous solution applications

KAUST Repository

Nunes, Suzana Pereira

2016-01-01

Block copolymers are known for their intricate morphology. We review the state of the art of block copolymer membranes and discuss perspectives in this field. The main focus is on pore morphology tuning with a short introduction on non-porous membranes. The two main strategies for pore formation in block copolymer membranes are (i) film casting and selective block sacrifice and (ii) self-assembly and non-solvent induced phase separation (SNIPS). Different fundamental aspects involved in the manufacture of block copolymer membranes are considered, including factors affecting the equilibrium morphology in solid films, self-assembly of copolymer in solutions and macrophase separation by solvent-non-solvent exchange. Different mechanisms are proposed for different depths of the SNIPS membrane. Block copolymer membranes can be prepared with much narrower pore size distribution than homopolymer membranes. Open questions and indications of what we consider the next development steps are finally discussed. They include the synthesis and application of new copolymers and specific functionalization, adding characteristics to respond to stimuli and chemical environment, polymerization-induced phase separation, and the manufacture of organic-inorganic hybrids.

Macromolecular nanotheranostics for multimodal anticancer therapy

Science.gov (United States)

Huis in't Veld, Ruben; Storm, Gert; Hennink, Wim E.; Kiessling, Fabian; Lammers, Twan

2011-10-01

Macromolecular carrier materials based on N-(2-hydroxypropyl)methacrylamide (HPMA) are prototypic and well-characterized drug delivery systems that have been extensively evaluated in the past two decades, both at the preclinical and at the clinical level. Using several different imaging agents and techniques, HPMA copolymers have been shown to circulate for prolonged periods of time, and to accumulate in tumors both effectively and selectively by means of the Enhanced Permeability and Retention (EPR) effect. Because of this, HPMA-based macromolecular nanotheranostics, i.e. formulations containing both drug and imaging agents within a single formulation, have been shown to be highly effective in inducing tumor growth inhibition in animal models. In patients, however, as essentially all other tumor-targeted nanomedicines, they are generally only able to improve the therapeutic index of the attached active agent by lowering its toxicity, and they fail to improve the efficacy of the intervention. Bearing this in mind, we have recently reasoned that because of their biocompatibility and their beneficial biodistribution, nanomedicine formulations might be highly suitable systems for combination therapies. In the present manuscript, we briefly summarize several exemplary efforts undertaken in this regard in our labs in the past couple of years, and we show that long-circulating and passively tumor-targeted macromolecular nanotheranostics can be used to improve the efficacy of radiochemotherapy and of chemotherapy combinations.

The synthesis of poly(lactide)-vitamin E TPGS (PLA-TPGS) copolymer and its utilization to formulate a curcumin nanocarrier

Science.gov (United States)

Thu Ha, Phuong; Nguyet Tran, Thi Minh; Duong Pham, Hong; Huan Nguyen, Quang; Phuc Nguyen, Xuan

2010-03-01

Curcumin is a natural substance that exhibits the ability to inhibit and/or treat carcinogenesis in a variety of cell lines, but because of its poor solubility in water the treatment efficacy is limited. In this paper we report on the fabrication of self-assembled micelle nanoparticles loaded with a curcumin drug by use of a biocompatible copolymer of PLA-TPGS (d-a-tocopheryl polyethylene glycol 1000 succinate—vitamin E TPGS) conjugate. The polylactide (PLA)-TPGS copolymer synthesized by ring-opening polymerization was characterized by Fourier transform infrared spectroscopy (FTIR) and 1H nuclear magnetic resonance (1H NMR) techniques. The surface morphology of PLA-TPGS and curcumin loaded PLA-TPGS was determined by field emission scanning electron microscopy (FE-SEM). The absorption and fluorescence examinations indicated that due to micellar capsulation the intensity of both types of spectra increased by about 4 times in comparison with those of the free curcumin sample.

The synthesis of poly(lactide)-vitamin E TPGS (PLA-TPGS) copolymer and its utilization to formulate a curcumin nanocarrier

International Nuclear Information System (INIS)

Thu Ha, Phuong; Nguyet Tran, Thi Minh; Pham, Hong Duong; Nguyen, Quang Huan; Nguyen, Xuan Phuc

2010-01-01

Curcumin is a natural substance that exhibits the ability to inhibit and/or treat carcinogenesis in a variety of cell lines, but because of its poor solubility in water the treatment efficacy is limited. In this paper we report on the fabrication of self-assembled micelle nanoparticles loaded with a curcumin drug by use of a biocompatible copolymer of PLA-TPGS (d-a-tocopheryl polyethylene glycol 1000 succinate—vitamin E TPGS) conjugate. The polylactide (PLA)-TPGS copolymer synthesized by ring-opening polymerization was characterized by Fourier transform infrared spectroscopy (FTIR) and 1 H nuclear magnetic resonance ( 1 H NMR) techniques. The surface morphology of PLA-TPGS and curcumin loaded PLA-TPGS was determined by field emission scanning electron microscopy (FE-SEM). The absorption and fluorescence examinations indicated that due to micellar capsulation the intensity of both types of spectra increased by about 4 times in comparison with those of the free curcumin sample

Polyether-polyester graft copolymer

Science.gov (United States)

Bell, Vernon L. (Inventor)

1987-01-01

Described is a polyether graft polymer having improved solvent resistance and crystalline thermally reversible crosslinks. The copolymer is prepared by a novel process of anionic copolymerization. These polymers exhibit good solvent resistance and are well suited for aircraft parts. Previous aromatic polyethers, also known as polyphenylene oxides, have certain deficiencies which detract from their usefulness. These commercial polymers are often soluble in common solvents including the halocarbon and aromatic hydrocarbon types of paint thinners and removers. This limitation prevents the use of these polyethers in structural articles requiring frequent painting. In addition, the most popular commercially available polyether is a very high melting plastic. This makes it considerably more difficult to fabricate finished parts from this material. These problems are solved by providing an aromatic polyether graft copolymer with improved solvent resistance and crystalline thermally reversible crosslinks. The graft copolymer is formed by converting the carboxyl groups of a carboxylated polyphenylene oxide polymer to ionic carbonyl groups in a suitable solvent, reacting pivalolactone with the dissolved polymer, and adding acid to the solution to produce the graft copolymer.

Micellar and antibody-targeted polymer therapeutics

Czech Academy of Sciences Publication Activity Database

Etrych, Tomáš; Chytil, Petr; Kovář, Lubomír; Říhová, Blanka; Ulbrich, Karel

2010-01-01

Roč. 295, - (2010), s. 1-12 ISSN 1022-1360. [Prague Meetings on Macromolecules /73./ New Frontiers in Macromolecular Science: From Macromolecular Concepts of Living Matter to Polymers for Better Quality of Life. Prague, 05.07.2009-09.07.2009] R&D Projects: GA AV ČR IAA400500806; GA AV ČR IAAX00500803; GA MŠk 1M0505 Institutional research plan: CEZ:AV0Z40500505; CEZ:AV0Z50200510 Keywords : doxorubicin * drug delivery systems * HPMA copolymers Subject RIV: CD - Macromolecular Chemistry

Mercapturic Acids Derived from the Toxicants Acrolein and Crotonaldehyde in the Urine of Cigarette Smokers from Five Ethnic Groups with Differing Risks for Lung Cancer.

Science.gov (United States)

Park, Sungshim L; Carmella, Steven G; Chen, Menglan; Patel, Yesha; Stram, Daniel O; Haiman, Christopher A; Le Marchand, Loic; Hecht, Stephen S

2015-01-01

The Multiethnic Cohort epidemiology study has clearly demonstrated that, compared to Whites and for the same number of cigarettes smoked, African Americans and Native Hawaiians have a higher risk for lung cancer whereas Latinos and Japanese Americans have a lower risk. Acrolein and crotonaldehyde are two important constituents of cigarette smoke which have well documented toxic effects and could play a role in lung cancer etiology. Their urinary metabolites 3-hydroxypropylmercapturic acid (3-HPMA) and 3-hydroxy-1-methylpropylmercapturic acid (HMPMA), respectively, are validated biomarkers of acrolein and crotonaldehyde exposure. We quantified levels of 3-HPMA and HMPMA in the urine of more than 2200 smokers from these five ethnic groups, and also carried out a genome wide association study using blood samples from these subjects. After adjusting for age, sex, creatinine, and total nicotine equivalents, geometric mean levels of 3-HPMA and HMPMA were significantly different in the five groups (P acrolein and crotonaldehyde may be involved in lung cancer etiology, and that their divergent levels may partially explain the differing risks of Native Hawaiian and Latino smokers. No strong signals were associated with 3-HPMA in the genome wide association study, suggesting that formation of the glutathione conjugate of acrolein is mainly non-enzymatic, while the top significant association with HMPMA was located on chromosome 12 near the TBX3 gene, but its relationship to HMPMA excretion is not clear.

Polyether/Polyester Graft Copolymers

Science.gov (United States)

Bell, Vernon L., Jr.; Wakelyn, N.; Stoakley, D. M.; Proctor, K. M.

1986-01-01

Higher solvent resistance achieved along with lower melting temperature. New technique provides method of preparing copolymers with polypivalolactone segments grafted onto poly (2,6-dimethyl-phenylene oxide) backbone. Process makes strong materials with improved solvent resistance and crystalline, thermally-reversible crosslinks. Resulting graft copolymers easier to fabricate into useful articles, including thin films, sheets, fibers, foams, laminates, and moldings.

PEO-related block copolymer surfactants

DEFF Research Database (Denmark)

Mortensen, K.

2001-01-01

Non-ionic block copolymer systems based on hydrophilic poly(ethylene oxide) and more hydrophobic co-polymer blocks are used intensively in a variety of industrial and personal applications. A brief description on the applications is presented. The physical properties of more simple model systems...... of such PEG-based block copolymers in aqueous suspensions are reviewed. Based on scattering experiments using either X-ray or neutrons, the phase behavior is characterized, showing that the thermo-reversible gelation is a result of micellar ordering into mesoscopic crystalline phases of cubic, hexagonal...

Electropolymerized Star-Shaped Benzotrithiophenes Yield π-Conjugated Hierarchical Networks with High Areal Capacitance

KAUST Repository

Ringk, Andreas

2016-03-30

High-surface-area π-conjugated polymeric networks have the potential to lend outstanding capacitance to supercapacitors because of the pronounced faradaic processes that take place across the dense intimate interface between active material and electrolytes. In this report, we describe how benzo[1,2-b:3,4-b’:5,6-b’’]trithiophene (BTT) and tris-EDOT-benzo[1,2-b:3,4-b’:5,6-b’’]trithiophene (TEBTT) can serve as 2D (trivalent) building blocks in the development of electropolymerized hierarchical π-conjugated frameworks with particularly high areal capacitance. In comparing electropolymerized networks of BTT, TEBTT, and their copolymers with EDOT, we show that P(TEBTT/EDOT)-based frameworks can achieve higher areal capacitance (e.g., as high as 443.8 mF cm-2 at 1 mA cm-2) than those achieved by their respective homopolymers (PTEBTT and PEDOT) in the same experimental conditions of electrodeposition (PTEBTT: 271.1 mF cm-2 (at 1 mA cm-2) and PEDOT: 12.1 mF cm-2 (at 1 mA cm-2)). For example, P(TEBTT/EDOT)-based frameworks synthesized in a 1:1 monomer-to-comonomer ratio show a ca. 35x capacitance improvement over PEDOT. The high areal capacitance measured for P(TEBTT/EDOT) copolymers can be explained by the open, highly porous hierarchical morphologies formed during the electropolymerization step. With >70% capacitance retention over 1,000 cycles (up to 89% achieved), both PTEBTT- and P(TEBTT/EDOT)-based frameworks are resilient to repeated electrochemical cycling and can be considered promising systems for high life cycle capacitive electrode applications.

Electropolymerized Star-Shaped Benzotrithiophenes Yield π-Conjugated Hierarchical Networks with High Areal Capacitance

KAUST Repository

Ringk, Andreas; Lignie, Adrien; Hou, Yuanfang; Alshareef, Husam N.; Beaujuge, Pierre

2016-01-01

High-surface-area π-conjugated polymeric networks have the potential to lend outstanding capacitance to supercapacitors because of the pronounced faradaic processes that take place across the dense intimate interface between active material and electrolytes. In this report, we describe how benzo[1,2-b:3,4-b’:5,6-b’’]trithiophene (BTT) and tris-EDOT-benzo[1,2-b:3,4-b’:5,6-b’’]trithiophene (TEBTT) can serve as 2D (trivalent) building blocks in the development of electropolymerized hierarchical π-conjugated frameworks with particularly high areal capacitance. In comparing electropolymerized networks of BTT, TEBTT, and their copolymers with EDOT, we show that P(TEBTT/EDOT)-based frameworks can achieve higher areal capacitance (e.g., as high as 443.8 mF cm-2 at 1 mA cm-2) than those achieved by their respective homopolymers (PTEBTT and PEDOT) in the same experimental conditions of electrodeposition (PTEBTT: 271.1 mF cm-2 (at 1 mA cm-2) and PEDOT: 12.1 mF cm-2 (at 1 mA cm-2)). For example, P(TEBTT/EDOT)-based frameworks synthesized in a 1:1 monomer-to-comonomer ratio show a ca. 35x capacitance improvement over PEDOT. The high areal capacitance measured for P(TEBTT/EDOT) copolymers can be explained by the open, highly porous hierarchical morphologies formed during the electropolymerization step. With >70% capacitance retention over 1,000 cycles (up to 89% achieved), both PTEBTT- and P(TEBTT/EDOT)-based frameworks are resilient to repeated electrochemical cycling and can be considered promising systems for high life cycle capacitive electrode applications.

Structure and optical bandgap relationship of π-conjugated systems.

Directory of Open Access Journals (Sweden)

André Leitão Botelho

Full Text Available In bulk heterojunction photovoltaic systems both the open-circuit voltage as well as the short-circuit current, and hence the power conversion efficiency, are dependent on the optical bandgap of the electron-donor material. While first-principles methods are computationally intensive, simpler model Hamiltonian approaches typically suffer from one or more flaws: inability to optimize the geometries for their own input; absence of general, transferable parameters; and poor performance for non-planar systems. We introduce a set of new and revised parameters for the adapted Su-Schrieffer-Heeger (aSSH Hamiltonian, which is capable of optimizing geometries, along with rules for applying them to any [Formula: see text]-conjugated system containing C, N, O, or S, including non-planar systems. The predicted optical bandgaps show excellent agreement to UV-vis spectroscopy data points from literature, with a coefficient of determination [Formula: see text], a mean error of -0.05 eV, and a mean absolute deviation of 0.16 eV. We use the model to gain insights from PEDOT, fused thiophene polymers, poly-isothianaphthene, copolymers, and pentacene as sources of design rules in the search for low bandgap materials. Using the model as an in-silico design tool, a copolymer of benzodithiophenes along with a small-molecule derivative of pentacene are proposed as optimal donor materials for organic photovoltaics.

New Copolymers Containing Charge Carriers for Organic Devices with ITO Films Treated by UV-Ozone Using High Intensity Discharge Lamp

Directory of Open Access Journals (Sweden)

Emerson Roberto SANTOS

2009-02-01

Full Text Available For electroluminescent devices new copolymers were synthesized using a Suzuki cross-coupling reaction based on monomers (fluorine-alt-phenylene in conjugation with quinoline-alt-phenylene units. They were characterized by 1H NMR, 13C NMR and FTIR. TGA measurements indicated that the copolymers have good thermal properties and no weight loss was observed up to 250 °C. The UV-Vis spectra were characterized by absorptions from the fluorene-alt-phenylene and quinoline-alt-phenylene segments in the backbone, while their photoluminescence (PL spectra dominated by emissions from the fluorene excimer. For devices assembly ITO films were treated using a High Intensity Discharge Lamp (HPMVL without outer bulb presenting high ozone concentration than that conventional germicidal lamp. The device with ITO treated revealed significant decrease of threshold voltage (or turn-on voltage compared by untreated with I-V curves. This decrease can be related by water and carbon dioxide extracted on surface after UV-Ozone treatment revealed by DRIFT measurements.

Biodegradable copolymers carrying cell-adhesion peptide sequences.

Science.gov (United States)

Proks, Vladimír; Machová, Lud'ka; Popelka, Stepán; Rypácek, Frantisek

2003-01-01

Amphiphilic block copolymers are used to create bioactive surfaces on biodegradable polymer scaffolds for tissue engineering. Cell-selective biomaterials can be prepared using copolymers containing peptide sequences derived from extracellular-matrix proteins (ECM). Here we discuss alternative ways for preparation of amphiphilic block copolymers composed of hydrophobic polylactide (PLA) and hydrophilic poly(ethylene oxide) (PEO) blocks with cell-adhesion peptide sequences. Copolymers PLA-b-PEO were prepared by a living polymerisation of lactide in dioxane with tin(II)2-ethylhexanoate as a catalyst. The following approaches for incorporation of peptides into copolymers were elaborated. (a) First, a side-chain protected Gly-Arg-Gly-Asp-Ser-Gly (GRGDSG) peptide was prepared by solid-phase peptide synthesis (SPPS) and then coupled with delta-hydroxy-Z-amino-PEO in solution. In the second step, the PLA block was grafted to it via a controlled polymerisation of lactide initiated by the hydroxy end-groups of PEO in the side-chain-protected GRGDSG-PEO. Deprotection of the peptide yielded a GRGDSG-b-PEO-b-PLA copolymer, with the peptide attached through its C-end. (b) A protected GRGDSG peptide was built up on a polymer resin and coupled with Z-carboxy-PEO using a solid-phase approach. After cleavage of the delta-hydroxy-PEO-GRGDSG copolymer from the resin, polymerisation of lactide followed by deprotection of the peptide yielded a PLA-b-PEO-b-GRGDSG block copolymer, in which the peptide is linked through its N-terminus.

Preparation and in vitro evaluation of polymer conjugates actively targeted using RGD-based peptides

Czech Academy of Sciences Publication Activity Database

Böhmová, Eliška; Pola, Robert; Pechar, Michal; Janoušková, Olga; Zuska, K.; Etrych, Tomáš

2017-01-01

Roč. 6, 4 (Suppl) (2017), s. 91 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 Institutional support: RVO:61389013 Keywords : polymer drug carriers * HPMA * peptide tumor targeting Subject RIV: CD - Macromolecular Chemistry

FTIR spectroscopy as an alternative tool for high gamma dose dosimetry using P(VDF-TrFE) fluorinated copolymers

Energy Technology Data Exchange (ETDEWEB)

Medeiros, Adriana S.; Liz, Otavio S., E-mail: asm@cdtn.b [Universidade Federal de Minas Gerais (DEN/UFMG), Belo Horizonte, MG (Brazil). Dept. de Engenharia Nuclear; Faria, Luiz O., E-mail: farialo@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

2011-07-01

Poly(vinylidene fluoride) [PVDF] is a semicrystalline homopolymer and some of its fluorinated copolymer has demonstrated to have sensitiveness to high doses of ionizing radiation. We have recently proposed a semicrystalline fluorinated PVDF copolymer, the poly(vinylidene-trifluorethylene) [P(VDF-TrFE], as a candidate for measuring larger dose ranges. In fact, in these copolymers the optical absorption peak at 274 nm has been used to measure gamma doses ranging from 1.0 to 100.0 kGy and the melting latent heat, collected by differential scanning calorimetry (DSC), have been used to measure gamma doses from 1.0 to 1,000.0 kGy. In this paper, the infrared stretching vibration of radio-induced in-chain unsaturations (CH=CF) in P(VDF-TrFE) copolymers has been considered as an alternative tool for high dose dosimetric purposes. FTIR spectroscopic data revealed two optical absorption bands at 1754 cm{sup -1} and 1854 cm{sup -1} whose intensities are unambiguously related to gamma delivered doses ranging from 100.0 kGy to 1,000.0 kGy. Fading was evaluated one month after irradiation. The results indicate that the sample dose evaluation should be performed in the first two hours after being exposed to the radiation beam. The radio-induced formation of unsaturations was also investigated by ultraviolet and visible spectroscopy, which has confirmed the gradual increase of conjugated C=C bonds with the absorbed dose. Our results indicate that quantitative analysis of FTIR absorption bands is a useful tool to perform a product end-point dosimetry in radiation processing facilities that use high gamma dose irradiation. (author)

Electrochromic in conjugated polymers

International Nuclear Information System (INIS)

Picado Valenzuela, Alfredo

2007-01-01

This revision considered object the description of one of the materials with the greatest potential in the field of electrochromic (mainly in the visible region): the conjugated polymers (CP), area of enormous potential both now and in a short time ahead. The CP are insulating materials and organic semiconductors in a state not doped. They can be doped positively or negatively being observed a significant increase in the conductivity and being generated a color change in these materials. The understanding of how optical properties vary based on the chemical structure of the polymer or its mixtures and more precisely of the alternatives that can be entered into the conjugated system or π system to obtain a material that besides to be flexible, environmentally stable, presents the colored states. The revision was centred chiefly in the polypyrrole (Ppy), the polythiophene (PTh) and their derivatives such as poly (3.4-ethylenedioxythiophene) (PEDOT). The advantage of using monomers with variable structure, to adjust the composition of the copolymer, or to blend with the PC, allows to obtain a variety of colored states that can be modulated through the visible spectrum and even with applications to wavelengths outside of this region. Because the PC presented at least two different colored states can be varied continuously as a function of the voltage applied. In some cases, they may submit multicoloured statements, which offers a range of possibilities for their application in flexible electronic devices type screens and windows. Applications include smart windows, camouflage clothing and data screens. This type of material is emerging as one of the substitutes of the traditional inorganic semiconductor, with the advantage of its low cost, high flexibility and the possibility to generate multiple colors through the handling of the monomers in the structure and control of energy of his band gap. (author) [es

Acyclic Diene Metathesis (ADMET Polymerization for Precise Synthesis of Defect-Free Conjugated Polymers with Well-Defined Chain Ends

Directory of Open Access Journals (Sweden)

Tahmina Haque

2015-03-01

Full Text Available This accounts introduces unique characteristics by adopting the acyclic diene metathesis (ADMET polymerization for synthesis of conjugated polymers, poly(arylene vinylenes, known as promising molecular electronics. The method is more suitable than the other methods in terms of atom efficiency affording defect-free, stereo-regular (exclusive trans polymers with well-defined chain ends; the resultant polymers possess better property than those prepared by the conventional methods. The chain ends (vinyl group in the resultant polymer prepared by ruthenium-carbene catalyst(s can be modified by treating with molybdenum-alkylidene complex (olefin metathesis followed by addition of various aldehyde (Wittig type cleavage, affording the end-functionalized polymers exclusively. An introduction of initiating fragment, the other conjugated segment, and one-pot synthesis of end-functionalized block copolymers, star shape polymers can be achieved by adopting this methodology.

Mechanical properties of weakly segregated block copolymers : 1. Synergism on tensile properties of poly(styrene-b-n-butylmethacrylate) diblock copolymers

NARCIS (Netherlands)

Weidisch, R.; Michler, G.H.; Fischer, H.; Arnold, M.; Hofmann, S.; Stamm, M.

1999-01-01

Mechanical properties of poly(styrene-b-n-butylmethacrylate) diblock copolymers, PS-b-PBMA, with different lengths of the polystyrene block were investigated. The copolymers display a composition range where the tensile strength of the block copolymers exceeds the values of the corresponding

Oil recovery with vinyl sulfonic acid-acrylamide copolymers

Energy Technology Data Exchange (ETDEWEB)

Norton, C.J.; Falk, D.O.

1973-12-18

An aqueous polymer flood containing sulfomethylated alkali metal vinyl sulfonate-acrylamide copolymers was proposed for use in secondary or tertiary enhanced oil recovery. The sulfonate groups on the copolymers sustain the viscosity of the flood in the presence of brine and lime. Injection of the copolymer solution into a waterflooded Berea core, produced 30.5 percent of the residual oil. It is preferred that the copolymers are partially hydrolyzed.

Amphiphilic graft copolymer based on poly(styrene-co-maleic anhydride with low molecular weight polyethylenimine for efficient gene delivery

Directory of Open Access Journals (Sweden)

Duan XP

2012-09-01

Full Text Available Xiaopin Duan,1,2 Jisheng Xiao,2 Qi Yin,2 Zhiwen Zhang,2 Shirui Mao,1 Yaping Li21School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, 2Center of Pharmaceutics, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, ChinaBackground and methods: A new amphiphilic comb-shaped copolymer (SP was synthesized by conjugating poly(styrene-co-maleic anhydride with low molecular weight polyethyleneimine for gene delivery. Fourier transform infrared spectrum, 1H nuclear magnetic resonance, and gel permeation chromatography were used to characterize the graft copolymer.Results: The buffering capability of SP was similar to that of polyethyleneimine within the endosomal pH range. The copolymer could condense DNA effectively to form complexes with a positive charge (13–30 mV and a small particle size (130–200 nm at N/P ratios between 5 and 20, and protect DNA from degradation by DNase I. In addition, SP showed much lower cytotoxicity than polyethyleneimine 25,000. Importantly, the gene transfection activity and cellular uptake of SP-DNA complexes were all markedly higher than that of complexes of polyethyleneimine 25,000 and DNA in MCF-7 and MCF-7/ADR cell lines.Conclusion: This work highlights the promise of SP as a safe and efficient synthetic vector for DNA delivery.Keywords: poly(styrene-co-maleic anhydride, polyethylenimine, DNA, gene delivery

iBodies: Modular Synthetic Antibody Mimetics Based on Hydrophilic Polymers Decorated with Functional Moieties

Czech Academy of Sciences Publication Activity Database

Šácha, Pavel; Knedlík, Tomáš; Schimer, Jiří; Tykvart, Jan; Parolek, Jan; Navrátil, Václav; Dvořáková, Petra; Sedlák, František; Ulbrich, Karel; Strohalm, Jiří; Majer, Pavel; Šubr, Vladimír; Konvalinka, Jan

2016-01-01

Roč. 55, č. 7 (2016), s. 2356-2360 ISSN 1433-7851 R&D Projects: GA ČR GBP208/12/G016; GA MŠk LO1302 Institutional support: RVO:61388963 ; RVO:61389013 Keywords : antibody mimetics * HPMA * molecular recognition * polymer conjugates * protein targeting Subject RIV: CE - Biochemistry; CD - Macromolecular Chemistry (UMCH-V) Impact factor: 11.994, year: 2016 http://onlinelibrary.wiley.com/doi/10.1002/anie.201508642/full

Applications of Tris(4-(thiophen-2-ylphenylamine- and Dithienylpyrrole-based Conjugated Copolymers in High-Contrast Electrochromic Devices

Directory of Open Access Journals (Sweden)

Tzi-Yi Wu

2016-05-01

Full Text Available Tris(4-(thiophen-2-ylphenylamine- and dithienylpyrrole-based copolymers (P(TTPA-co-DIT and P(TTPA-co-BDTA were electropolymerized on ITO electrode by applying constant potentials of 1.0, 1.1, and 1.2 V. Spectroelectrochemical investigations revealed that P(TTPA-co-DIT film displayed more color changes than P(TTPA-co-BDTA film. The P(TTPA-co-DIT film is yellow in the neutral state, yellowish-green and green in the intermediate state, and blue (1.2 V in highly oxidized state. The ∆Tmax of the P(TTPA-co-DIT and P(TTPA-co-BDTA films were measured as 60.3% at 1042 nm and 47.1% at 1096 nm, respectively, and the maximum coloration efficiency (η of P(TTPA-co-DIT and P(TTPA-co-BDTA films were calculated to be 181.9 cm2·C−1 at 1042 nm and 217.8 cm2·C−1 at 1096 nm, respectively, in an ionic liquid solution. Dual type electrochromic devices (ECDs consisting of P(TTPA-co-DIT (or P(TTPA-co-BDTA anodic copolymer, ionic liquid-based electrolyte, and poly(3,4-(2,2-diethylpropylenedioxythiophene (PProDOT-Et2 cathodic polymer were constructed. P(TTPA-co-BDTA/PProDOT-Et2 ECD showed high ΔTmax (48.1% and high coloration efficiency (649.4 cm2·C−1 at 588 nm. Moreover, P(TTPA-co-DIT/PProDOT-Et2 and P(TTPA-co-BDTA/PProDOT-Et2 ECDs displayed satisfactory optical memory and long term switching stability.

Micelles of zinc protoporphyrin conjugated to N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer for imaging and light-induced antitumor effects in vivo

Czech Academy of Sciences Publication Activity Database

Nakamura, H.; Liao, L.; Hitaka, Y.; Tsukigawa, K.; Šubr, Vladimír; Fang, J.; Ulbrich, Karel; Maeda, H.

2013-01-01

Roč. 165, č. 3 (2013), s. 191-198 ISSN 0168-3659 R&D Projects: GA AV ČR IAAX00500803 Institutional research plan: CEZ:AV0Z40500505 Institutional support: RVO:61389013 Keywords : fluorescence imaging * fluorescent nanoprobe * singlet oxygen Subject RIV: CD - Macromolecular Chemistry Impact factor: 7.261, year: 2013

21 CFR 177.1320 - Ethylene-ethyl acrylate copolymers.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethylene-ethyl acrylate copolymers. 177.1320... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1320 Ethylene-ethyl acrylate copolymers. Ethylene-ethyl acrylate copolymers may be safely used to produce packaging materials, containers...

Sulfomethylated graft copolymers of xanthan gum and polyacrylamide

Energy Technology Data Exchange (ETDEWEB)

Cottrell, I.W.; Empey, R.A.; Racciato, J.S.

1978-08-08

A water-soluble anionic graft copolymer of xanthan gum and polyacrylamide is described in which at least part of the amide function of the acrylamide portion of the copolymer is sulfomethylated and the xanthan gum portion of the copolymer is unreacted with formaldehyde. The copolymer is sulfomethylated by reaction with formaldehyde and sodium metabisulfite. The formaldehyde does not cause any appreciable cross-linking between hydroxyl groups of the xanthan moieties. The sulfomethylation of the acrylamido group takes place at temperatures from 35 to 70 C. The pH is 10 or higher, typically from 12 to 13. The degree of anionic character may be varied by adjusting the molar ratio of formaldehyde and sodium metabisulfite with respect to the copolymer. 10 claims.

Block Copolymers: Synthesis and Applications in Nanotechnology

Science.gov (United States)

Lou, Qin

This study is focused on the synthesis and study of (block) copolymers using reversible deactivation radical polymerizations (RDRPs), including atom transfer radical polymerization (ATRP) and reversible addition-fragmentation chain transfer (RAFT) polymerization. In particular, two primary areas of study are undertaken: (1) a proof-of-concept application of lithographic block copolymers, and (2) the mechanistic study of the deposition of titania into block copolymer templates for the production of well-ordered titania nanostructures. Block copolymers have the ability to undergo microphase separation, with an average size of each microphase ranging from tens to hundreds of nanometers. As such, block copolymers have been widely considered for nanotechnological applications over the past two decades. The development of materials for various nanotechnologies has become an increasingly studied area as improvements in many applications, such as those found in the semiconductor and photovoltaic industries are constantly being sought. Significant growth in developments of new synthetic methods ( i.e. RDRPs) has allowed the production of block copolymers with molecular (and sometimes atomic) definition. In turn, this has greatly expanded the use of block copolymers in nanotechnology. Herein, we describe the synthesis of statistical and block copolymers of 193 nm photolithography methacrylate and acrylate resist monomers with norbornyl and adamantyl moieties using RAFT polymerization.. For these resist (block) copolymers, the phase separation behaviors were examined by atomic force microscopy (AFM). End groups were removed from the polymers to avoid complications during the photolithography since RAFT end groups absorb visible light. Poly(glycidyl methacrylate-block-polystyrene) (PGMA-b-PS) was synthesize by ATRP and demonstrated that this block copolymer acts as both a lithographic UV (365 nm) photoresist and a self-assembly material. The PGMA segments can undergo cationic

Naphtho[1,2-b:5,6-b']dithiophene-Based Conjugated Polymers for Fullerene-Free Inverted Polymer Solar Cells.

Science.gov (United States)

Jiang, Zhaoyan; Li, Huan; Wang, Zhen; Zhang, Jianqi; Zhang, Yajie; Lu, Kun; Wei, Zhixiang

2018-03-23

Three novel copolymers based on zigzag naphthodithiophene (zNDT) with different aromatic rings as π bridges and different core side substitutions are designed and synthesized (PzNDT-T-1,3-bis(4-(2-ethylhexyl)-thiophen-2-yl)-5,7-bis(2-ethylhexyl)benzo[1,2-c:4,5-c']-dithiophene-4,8-dione (BDD), PzNDT-TT-BDD, and PzNDTP-T-BDD, respectively). The 2D conjugation structure and molecular planarity of the polymers can be effectively altered through the modification of conjugated side chains and π-bridges. These alterations contribute to the variation in energy levels, light absorption capacity, and morphology compatibility of the polymers. When blended with the nonfullerene acceptor (2,2'-[(4,4,9,9-tetrahexyl-4,9-dihydro-sindaceno[1,2-b:5,6-b']dithiophene-2,7-diyl)bis[methylidyne(3-oxo-1H-indene-2,1(3H)-diylidene)

21 CFR 177.1310 - Ethylene-acrylic acid copolymers.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethylene-acrylic acid copolymers. 177.1310 Section... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1310 Ethylene-acrylic acid copolymers. The ethylene-acrylic acid copolymers identified in paragraph (a) of this section may be safely...

21 CFR 177.1312 - Ethylene-carbon monoxide copolymers.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethylene-carbon monoxide copolymers. 177.1312... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1312 Ethylene-carbon monoxide copolymers. The ethylene-carbon monoxide copolymers identified in paragraph (a) of this section may be safely...

21 CFR 177.1350 - Ethylene-vinyl acetate copolymers.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethylene-vinyl acetate copolymers. 177.1350 Section... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1350 Ethylene-vinyl acetate copolymers. Ethylene-vinyl acetate copolymers may be safely used as articles or components of articles...

21 CFR 177.1950 - Vinyl chloride-ethylene copolymers.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Vinyl chloride-ethylene copolymers. 177.1950... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1950 Vinyl chloride-ethylene copolymers. The vinyl chloride-ethylene copolymers identified in paragraph (a) of this section may be safely...

Antimicrobial activity of poly(acrylic acid) block copolymers

Energy Technology Data Exchange (ETDEWEB)

Gratzl, Günther, E-mail: guenther.gratzl@jku.at [Johannes Kepler University Linz, Institute for Chemical Technology of Organic Materials, Altenberger Str. 69, 4040 Linz (Austria); Paulik, Christian [Johannes Kepler University Linz, Institute for Chemical Technology of Organic Materials, Altenberger Str. 69, 4040 Linz (Austria); Hild, Sabine [Johannes Kepler University Linz, Institute of Polymer Science, Altenberger Str. 69, 4040 Linz (Austria); Guggenbichler, Josef P.; Lackner, Maximilian [AMiSTec GmbH and Co. KG, Leitweg 13, 6345 Kössen, Tirol (Austria)

2014-05-01

The increasing number of antibiotic-resistant bacterial strains has developed into a major health problem. In particular, biofilms are the main reason for hospital-acquired infections and diseases. Once formed, biofilms are difficult to remove as they have specific defense mechanisms against antimicrobial agents. Antimicrobial surfaces must therefore kill or repel bacteria before they can settle to form a biofilm. In this study, we describe that poly(acrylic acid) (PAA) containing diblock copolymers can kill bacteria and prevent from biofilm formation. The PAA diblock copolymers with poly(styrene) and poly(methyl methacrylate) were synthesized via anionic polymerization of tert-butyl acrylate with styrene or methyl methacrylate and subsequent acid-catalyzed hydrolysis of the tert-butyl ester. The copolymers were characterized via nuclear magnetic resonance spectroscopy (NMR), size-exclusion chromatography (SEC), Fourier transform infrared spectroscopy (FTIR), elemental analysis, and acid–base titrations. Copolymer films with a variety of acrylic acid contents were produced by solvent casting, characterized by atomic force microscopy (AFM) and tested for their antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. The antimicrobial activity of the acidic diblock copolymers increased with increasing acrylic acid content, independent of the copolymer-partner, the chain length and the nanostructure. - Highlights: • Acrylic acid diblock copolymers are antimicrobially active. • The antimicrobial activity depends on the acrylic acid content in the copolymer. • No salts, metals or other antimicrobial agents are needed.

Antimicrobial activity of poly(acrylic acid) block copolymers

International Nuclear Information System (INIS)

Gratzl, Günther; Paulik, Christian; Hild, Sabine; Guggenbichler, Josef P.; Lackner, Maximilian

2014-01-01

The increasing number of antibiotic-resistant bacterial strains has developed into a major health problem. In particular, biofilms are the main reason for hospital-acquired infections and diseases. Once formed, biofilms are difficult to remove as they have specific defense mechanisms against antimicrobial agents. Antimicrobial surfaces must therefore kill or repel bacteria before they can settle to form a biofilm. In this study, we describe that poly(acrylic acid) (PAA) containing diblock copolymers can kill bacteria and prevent from biofilm formation. The PAA diblock copolymers with poly(styrene) and poly(methyl methacrylate) were synthesized via anionic polymerization of tert-butyl acrylate with styrene or methyl methacrylate and subsequent acid-catalyzed hydrolysis of the tert-butyl ester. The copolymers were characterized via nuclear magnetic resonance spectroscopy (NMR), size-exclusion chromatography (SEC), Fourier transform infrared spectroscopy (FTIR), elemental analysis, and acid–base titrations. Copolymer films with a variety of acrylic acid contents were produced by solvent casting, characterized by atomic force microscopy (AFM) and tested for their antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. The antimicrobial activity of the acidic diblock copolymers increased with increasing acrylic acid content, independent of the copolymer-partner, the chain length and the nanostructure. - Highlights: • Acrylic acid diblock copolymers are antimicrobially active. • The antimicrobial activity depends on the acrylic acid content in the copolymer. • No salts, metals or other antimicrobial agents are needed

Copolymers at the solid - liquid interface

NARCIS (Netherlands)

Wijmans, C.M.

1994-01-01

Copolymers consisting of both adsorbing and nonadsorbing segments can show an adsorption behaviour which is very different from that of homopolymers. We have mainly investigated the adsorption of AB diblock copolymers, which have one adsorbing block (anchor) and one nonadsorbing block

HPMA-based polymeric micelles for curcumin solubilization and inhibition of cancer cell growth

NARCIS (Netherlands)

Naksuriya, Ornchuma; Shi, Yang; Van Nostrum, Cornelus F.|info:eu-repo/dai/nl/134498690; Anuchapreeda, Songyot; Hennink, Wim E.|info:eu-repo/dai/nl/070880409; Okonogi, Siriporn

2015-01-01

Abstract Curcumin (CM) has been reported as a potential anticancer agent. However, its pharmaceutical applications as therapeutic agent are hampered because of its poor aqueous solubility. The present study explores the advantages of polymeric micelles composed of block copolymers of

Vegetable-Oil-Based Hyperbranched Polyester-Styrene Copolymer Containing Silver Nanoparticle as Antimicrobial and Corrosion-Resistant Coating Materials

Directory of Open Access Journals (Sweden)

Manawwer Alam

2013-01-01

Full Text Available Pongamia oil (PO was converted to Pongamia oil hydroxyl (POH via epoxidation process. The esterification of POH with linolenic acid was carried out to form hyperbranched polyester (HBPE, and further styrenation was performed at the conjugated double bond in the chain of linolenic acid. After styrenation, silver nanoparticle was added in different weight percentages (0.1–0.4 wt%. The structural elucidation of POH, HBPE, and HBPE-St was carried out by FT-IR, 1H-NMR, and 13C-NMR spectroscopic techniques. Physicochemical and physicomechanical analyses were performed by standard method. Thermal behavior of the HBPE-St was analyzed by using thermogravimetric analysis (TGA and differential scanning calorimetry (DSC. The coatings of HBPE-St were prepared on mild steel strips. The anticorrosive behavior of HBPE-St resin-based coatings in acid, saline, and tap water was evaluated, and the molecular weight of HBPE-St was determined by gel permeation chromatography (GPC. The antibacterial activities of the HBPE-St copolymers were tested in vitro against bacteria and fungi by disc diffusion method. The HBPE-St copolymers exhibited good antibacterial activities and can be used as antimicrobial and corrosion-resistant coating materials.

Flexible control of cellular encapsulation, permeability, and release in a droplet-templated bifunctional copolymer scaffold.

Science.gov (United States)

Chen, Qiushui; Chen, Dong; Wu, Jing; Lin, Jin-Ming

2016-11-01

Designing cell-compatible, bio-degradable, and stimuli-responsive hydrogels is very important for biomedical applications in cellular delivery and micro-scale tissue engineering. Here, we report achieving flexible control of cellular microencapsulation, permeability, and release by rationally designing a diblock copolymer, alginate-conjugated poly(N-isopropylacrylamide) (Alg-co-PNiPAM). We use the microfluidic technique to fabricate the bifunctional copolymers into thousands of mono-disperse droplet-templated hydrogel microparticles for controlled encapsulation and triggered release of mammalian cells. In particular, the grafting PNiPAM groups in the synthetic cell-laden microgels produce lots of nano-aggregates into hydrogel networks at elevated temperature, thereafter enhancing the permeability of microparticle scaffolds. Importantly, the hydrogel scaffolds are readily fabricated via on-chip quick gelation by triggered release of Ca 2+ from the Ca-EDTA complex; it is also quite exciting that very mild release of microencapsulated cells is achieved via controlled degradation of hydrogel scaffolds through a simple strategy of competitive affinity of Ca 2+ from the Ca-Alginate complex. This finding suggests that we are able to control cellular encapsulation and release through ion-induced gelation and degradation of the hydrogel scaffolds. Subsequently, we demonstrate a high viability of microencapsulated cells in the microgel scaffolds.

Synthesis and characterization of waterborne polyurethane acrylate copolymers

International Nuclear Information System (INIS)

Sultan, Misbah; Bhatti, Haq Nawaz; Zuber, Mohammad; Barikani, Mehdi

2013-01-01

Polyurethane acrylate copolymers were synthesized by emulsion polymerization process. To reduce the environmental hazards, organic solvents were replaced by eco-friendly aqueous system. Concentration of polyurethane and acrylate monomer was varied to investigate the effect of chemical composition on performance properties of copolymers. FTIR spectroscopy was used as a key tool to record the chemical synthesis route. The synthesized copolymer emulsions were characterized by evaluating their particle size, viscosity, dry weight content, chemical and water resistance. Thermal decomposition was studied by thermogravimetric analysis. Scanning electron microscope was used to visualize the morphological structure of copolymers. The experimental results indicate better polyurethane acrylate compatibility till the ratio of 30/70. However, these copolymers exhibited synergistic effects between the two polymers and revealed a remarkable improvement in numerous coating properties

Alcohol vapor sensory properties of nanostructured conjugated polymers

International Nuclear Information System (INIS)

Bearzotti, Andrea; Macagnano, Antonella; Pantalei, Simone; Zampetti, Emiliano; Venditti, Iole; Fratoddi, Ilaria; Vittoria Russo, Maria

2008-01-01

The response to relative humidity (RH) and alcohol vapors of resistive-type sensors based on nanobeads of conjugated polymers, namely polyphenylacetylene (PPA) and copolymer poly[phenylacetylene-(co-2-hydroxyethyl methacrylate)] (P(PA/HEMA)), were investigated. Sensors based on ordered arrays of these nanostructured polymeric materials showed stable and reproducible current intensity variations in the range 10-90% of relative humidity at room temperature. Both polymers also showed sensitivity to aliphatic chain primary alcohols, and a fine tuning of the sensor response was obtained by varying the chain length of the alcohol in relation to the polarity. The nanostructured feature of polymeric-based membranes seems to have an effect on the sensing response and an enhancement of the sensitivity was observed for the response to water and alcohol vapor variations with respect to previous studies based on amorphous polyphenylacetylene. High stability of the polymeric nanostructured membranes was detected with no aging after two weeks in continuum stressing measurement conditions.

The influence of chain stretching on the phase behavior of multiblock copolymer and comb copolymer melts

NARCIS (Netherlands)

Angerman, HJ; ten Brinke, G

The subject of this paper is inspired by microphase-separated copolymer melts in which a small-scale structure is present inside one of the phases of a large-scale structure. Such a situation can arise in a diblock copolymer melt, if one of the blocks of the diblock is in itself a multiblock

Polyketones as alternating copolymers of carbon monoxide

International Nuclear Information System (INIS)

Belov, Gennady P; Novikova, Elena V

2004-01-01

Characteristic features of the catalytic synthesis of alternating copolymers of carbon monoxide with various olefins, dienes, styrene and its derivatives are considered. The diversity of catalyst systems used for the copolymerisation of carbon monoxide is demonstrated and their influence on the structure and the molecular mass of the resulting copolymers is analysed. The data on the structure and physicochemical and mechanical properties of this new generation of functional copolymers are generalised and described systematically for the first time.

21 CFR 177.2470 - Polyoxymethylene copolymer.

Science.gov (United States)

2010-04-01

... Components of Articles Intended for Repeated Use § 177.2470 Polyoxymethylene copolymer. Polyoxymethylene copolymer identified in this section may be safely used as an article or component of articles intended for... are available from the Center for Food Safety and Applied Nutrition (HFS-200), Food and Drug...

Nanoparticles based on novel amphiphilic polyaspartamide copolymers

International Nuclear Information System (INIS)

Craparo, Emanuela Fabiola; Teresi, Girolamo; Ognibene, Maria Chiara; Casaletto, Maria Pia; Bondi, Maria Luisa; Cavallaro, Gennara

2010-01-01

In this article, the synthesis of two amphiphilic polyaspartamide copolymers, useful to obtain polymeric nanoparticles without using surfactants or stabilizing agents, is described. These copolymers were obtained starting from α,β-poly-(N-2-hydroxyethyl)-dl-aspartamide (PHEA) by following a novel synthetic strategy. In particular, PHEA and its pegylated derivative (PHEA-PEG 2000 ) were functionalized with poly(lactic acid) (PLA) through 1,1'-carbonyldiimidazole (CDI) activation to obtain PHEA-PLA and PHEA-PEG 2000 -PLA graft copolymers, respectively. These copolymers were properly purified and characterized by 1 H-NMR, FT-IR, and Size Exclusion Chromatography (SEC) analyses, which confirmed that derivatization reactions occurred. Nanoparticles were obtained from PHEA-PLA and PHEA-PEG 2000 -PLA graft copolymers by using the high pressure homogenization-solvent evaporation method, avoiding the use of surfactants or stabilizing agents. Polymeric nanoparticles were characterized by dimensional analysis, before and after freeze-drying process, and Scanning Electron Microscopy (SEM). Zeta potential measurements and X-ray Photoelectron Spectroscopy (XPS) analysis demonstrated the presence of PEG and/or PHEA onto the PHEA-PEG 2000 -PLA and PHEA-PLA nanoparticle surface, respectively.

Cationic albumin-conjugated pegylated nanoparticles as novel drug carrier for brain delivery.

Science.gov (United States)

Lu, Wei; Zhang, Yan; Tan, Yu-Zhen; Hu, Kai-Li; Jiang, Xin-Guo; Fu, Shou-Kuan

2005-10-20

In this paper, a novel drug carrier for brain delivery, cationic bovine serum albumin (CBSA) conjugated with poly(ethyleneglycol)-poly(lactide) (PEG-PLA) nanoparticle (CBSA-NP), was developed and its effects were evaluated. The copolymers of methoxy-PEG-PLA and maleimide-PEG-PLA were synthesized by ring opening polymerization of D,L-lactide initiated by methoxy-PEG and maleimide-PEG, respectively, which were applied to prepare pegylated nanoparticles by means of double emulsion and solvent evaporation procedure. Native bovine serum albumin (BSA) was cationized and thiolated, followed by conjugation through the maleimide function located at the distal end of PEG surrounding the nanoparticle's surface. Transmission electron micrograph (TEM) and dynamic light scattering results showed that CBSA-NP had a round and regular shape with a mean diameter around 100 nm. Surface nitrogen was detected by X-ray photoelectron spectroscopy (XPS), and colloidal gold stained around the nanoparticle's surface was visualized in TEM, which proved that CBSA was covalently conjugated onto its surface. To evaluate the effects of brain delivery, BSA conjugated with pegylated nanoparticles (BSA-NP) was used as the control group and 6-coumarin was incorporated into the nanoparticles as the fluorescent probe. The qualitative and quantitative results of CBSA-NP uptake experiment compared with those of BSA-NP showed that rat brain capillary endothelial cells (BCECs) took in much more CBSA-NP than BSA-NP at 37 degrees C, at different concentrations and time incubations. After a dose of 60 mg/kg CBSA-NP or BSA-NP injection in mice caudal vein, fluorescent microscopy of brain coronal sections showed a higher accumulation of CBSA-NP in the lateral ventricle, third ventricle and periventricular region than that of BSA-NP. There was no difference on BCECs' viability between CBSA-conjugated and -unconjugated pegylated nanoparticles. The significant results in vitro and in vivo showed that CBSA-NP was

Amphiphilic copolymers for fouling-release coatings

DEFF Research Database (Denmark)

Noguer, Albert Camós; Olsen, Stefan Møller; Hvilsted, Søren

of the coatings [9,10,11]. This work shows the effect of an amphiphilic copolymer that induces hydrophilicity on the surface of the silicone-based fouling release coatings. The behaviour of these copolymers within the coating upon immersion and the interaction of these surface-active additives with other...

Poly(ferrocenylsilane)-block-Polylactide Block Copolymers

NARCIS (Netherlands)

Roerdink, M.; van Zanten, Thomas S.; Hempenius, Mark A.; Zhong, Zhiyuan; Feijen, Jan; Vancso, Gyula J.

2007-01-01

A PFS/PLA block copolymer was studied to probe the effect of strong surface interactions on pattern formation in PFS block copolymer thin films. Successful synthesis of PFS-b-PLA was demonstrated. Thin films of these polymers show phase separation to form PFS microdomains in a PLA matrix, and

Research Update: Triblock copolymers as templates to synthesize inorganic nanoporous materials

OpenAIRE

Yunqi Li; Bishnu Prasad Bastakoti; Yusuke Yamauchi

2016-01-01

This review focuses on the application of triblock copolymers as designed templates to synthesize nanoporous materials with various compositions. Asymmetric triblock copolymers have several advantages compared with symmetric triblock copolymers and diblock copolymers, because the presence of three distinct domains can provide more functional features to direct the resultant nanoporous materials. Here we clearly describe significant contributions of asymmetric triblock copolymers, especially p...

Micellization and Dynamics of a Block Copolymer

DEFF Research Database (Denmark)

Hvidt, Søren

2006-01-01

and copolymer mixtures, and evidence in favor of a multi-equilibria unimer-micelle model will be presented. Results obtained by liquid chromatographic methods will be shown and it will be demonstrated that commercial EPE copolymers are inhomogeneous at several levels and many of their unusual properties reflect...... ratios and temperature. The micellization process with increasing temperature has been followed by a number of techniques including differential scanning calorimetry, liquid chromatography, and surface tension measurements. Different micellization models have been tested for purified copolymers...

Acrylonitrile-methyl Methacrylate Copolymer Films Containing Microencapsulated n-Octadecane

Institute of Scientific and Technical Information of China (English)

LI Jun; HAN Na; ZHANG Xing-xiang

2006-01-01

Acrylonitrile-methyl methacrylate copolymer was synthesized in aqueous solution by Redox. The copolymer was mixed with 10 - 40 wt% of microencapsulated n-octadecane (MicroPCMs) in water. Copolymer films containing MicroPCMs were cast at room temperature in N, N-Dimethylformamide solution. The copolymer of acrylonitrile-methyl methacrylate and the copolymer films containing MicroPCMs were characterized by using Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), Thermogravimetric Analyzer (TG), X-ray Diffrac tion (XRD) and Scanning Electron Microscopy (SEM), etc.The microcapsules in the films are evenly distributed in the copolymer matrix. The heat-absorbing temperatures and heat-evolving temperatures of the films are almost the same as that of the MicroPCMs, respectively, and fluctuate in a slight range. In addition, the enthalpy efficiency of MicroPCMs rises with the contents of MicroPCMs increasing.The crystallinity of the film increases with the contents of MicroPCMs increasing.

Tuning crystalline ordering by annealing and additives to study its effect on exciton diffusion in a polyalkylthiophene copolymer.

Science.gov (United States)

Chowdhury, Mithun; Sajjad, Muhammad T; Savikhin, Victoria; Hergué, Noémie; Sutija, Karina B; Oosterhout, Stefan D; Toney, Michael F; Dubois, Philippe; Ruseckas, Arvydas; Samuel, Ifor D W

2017-05-17

The influence of various processing conditions on the singlet exciton diffusion is explored in films of a conjugated random copolymer poly-(3-hexylthiophene-co-3-dodecylthiophene) (P3HT-co-P3DDT) and correlated with the degree of crystallinity probed by grazing incidence X-ray scattering and with exciton bandwidth determined from absorption spectra. The exciton diffusion coefficient is deduced from exciton-exciton annihilation measurements and is found to increase by more than a factor of three when thin films are annealed using CS 2 solvent vapour. A doubling of exciton diffusion coefficient is observed upon melt annealing at 200 °C and the corresponding films show about 50% enhancement in the degree of crystallinity. In contrast, films fabricated from polymer solutions containing a small amount of either solvent additive or nucleating agent show a decrease in exciton diffusion coefficient possibly due to formation of traps for excitons. Our results suggest that the enhancement of exciton diffusivity occurs because of increased crystallinity of alkyl-stacking and longer conjugation of aggregated chains which reduces the exciton bandwidth.

Lactosylated poly(ethylene oxide)-poly(propylene oxide) block copolymers for potential active targeting: synthesis and physicochemical and self-aggregation characterization

Energy Technology Data Exchange (ETDEWEB)

Cuestas, Maria L.; Glisoni, Romina J. [University of Buenos Aires, Group of Biomaterials and Nanotechnology for Improved Medicines (BIONIMED), Department of Pharmaceutical Technology, Faculty of Pharmacy and Biochemistry (Argentina); Mathet, Veronica L. [National Science Research Council (CONICET) (Argentina); Sosnik, Alejandro, E-mail: alesosnik@gmail.com [University of Buenos Aires, The Group of Biomaterials and Nanotechnology for Improved Medicines (BIONIMED), Department of Pharmaceutical Technology, Faculty of Pharmacy and Biochemistry (Argentina)

2013-01-15

Aiming to develop polymeric self-assembly nanocarriers with potential applications in active drug targeting to the liver, linear and branched poly(ethylene oxide)-poly(propylene oxide) amphiphiles were conjugated to lactobionic acid (LA), a disaccharide of galactose and gluconic acid, by the conventional Steglich esterification reaction. The conjugation was confirmed by ATR/FT-IR, {sup 1}H-NMR, and {sup 13}C-NMR spectroscopy. Elemental analysis and MALDI-TOF mass spectrometry were employed to elucidate the conjugation extent and the final molecular weight, respectively. The critical micellar concentration (CMC), the size and size distribution and zeta potential of the pristine and modified polymeric micelles under different conditions of pH and temperature were characterized by dynamic light scattering (DLS). Conjugation with LA favored the micellization process, leading to a decrease of the CMC with respect to the pristine counterpart, this phenomenon being independent of the pH and the temperature. At 37 Degree-Sign C, micelles made of pristine copolymers showed a monomodal size distribution between 12.8 and 24.4 nm. Conversely, LA-conjugated micelles showed a bimodal size pattern that comprised a main fraction of relatively small size (11.6-22.2 nm) and a second one with remarkably larger sizes of up to 941.4 nm. The former corresponded to single micelles, while the latter would indicate a secondary aggregation phenomenon. The spherical morphology of LA-micelles was visualized by transmission electron microscopy (TEM). Finally, to assess the ability of the LA-conjugated micelles to interact with lectin-like receptors, samples were incubated with concanavalin A at 37 Degree-Sign C and the size and size distribution were monitored by DLS. Findings indicated that regardless of the relatively weak affinity of this vegetal lectin for galactose, micelles underwent agglutination probably through the interaction of a secondary site in the lectin with the gluconic acid

Functional Nanoporous Polymers from Block Copolymer Precursors

DEFF Research Database (Denmark)

Guo, Fengxiao

Abstract Self-assembly of block copolymers provides well-defined morphologies with characteristic length scales in the nanometer range. Nanoporous polymers prepared by selective removal of one block from self-assembled block copolymers offer great technological promise due to their many potential...... functionalities remains a great challenge due to the limitation of available polymer synthesis and the nanoscale confinement of the porous cavities. The main topic of this thesis is to develop methods for fabrication of functional nanoporous polymers from block copolymer precursors. A method has been developed......, where living anionic polymerization and atom transfer radical polymerization (ATRP) are combined to synthesize a polydimethylsiloxane-b-poly(tert-butyl acrylate)-b-polystyrene (PDMS-b-PtBA-b-PS) triblock copolymer precursor. By using either anhydrous hydrogen fluoride or trifluoroacetic acid, PtBA block...

Morphological studies on block copolymer modified PA 6 blends

Energy Technology Data Exchange (ETDEWEB)

Poindl, M., E-mail: marcus.poindl@ikt.uni-stuttgart.de, E-mail: christian.bonten@ikt.uni-stuttgart.de; Bonten, C., E-mail: marcus.poindl@ikt.uni-stuttgart.de, E-mail: christian.bonten@ikt.uni-stuttgart.de [Institut für Kunststofftechnik, University of Stuttgart (Germany)

2014-05-15

Recent studies show that compounding polyamide 6 (PA 6) with a PA 6 polyether block copolymers made by reaction injection molding (RIM) or continuous anionic polymerization in a reactive extrusion process (REX) result in blends with high impact strength and high stiffness compared to conventional rubber blends. In this paper, different high impact PA 6 blends were prepared using a twin screw extruder. The different impact modifiers were an ethylene propylene copolymer, a PA PA 6 polyether block copolymer made by reaction injection molding and one made by reactive extrusion. To ensure good particle matrix bonding, the ethylene propylene copolymer was grafted with maleic anhydride (EPR-g-MA). Due to the molecular structure of the two block copolymers, a coupling agent was not necessary. The block copolymers are semi-crystalline and partially cross-linked in contrast to commonly used amorphous rubbers which are usually uncured. The combination of different analysis methods like atomic force microscopy (AFM), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) gave a detailed view in the structure of the blends. Due to the partial cross-linking, the particles of the block copolymers in the blends are not spherical like the ones of ethylene propylene copolymer. The differences in molecular structure, miscibility and grafting of the impact modifiers result in different mechanical properties and different blend morphologies.

Photo-Induced Micellization of Block Copolymers

Directory of Open Access Journals (Sweden)

Satoshi Kuwayama

2010-11-01

Full Text Available We found novel photo-induced micellizations through photolysis, photoelectron transfer, and photo-Claisen rearrangement. The photolysis-induced micellization was attained using poly(4-tert-butoxystyrene-block-polystyrene diblock copolymer (PBSt-b-PSt. BSt-b-PSt showed no self-assembly in dichloromethane and existed as isolated copolymers. Dynamic light scattering demonstrated that the copolymer produced spherical micelles in this solvent due to irradiation with a high-pressure mercury lamp in the presence of photo-acid generators, such as bis(alkylphenyliodonium hexafluorophosphate, diphenyliodonium hexafluorophosphate, and triphenylsulfonium triflate. The 1H NMR analysis confirmed that PBSt-b-PSt was converted into poly(4-vinylphenol-block-PSt by the irradiation, resulting in self-assembly into micelles. The irradiation in the presence of the photo-acid generator also induced the micellization of poly(4-pyridinemethoxymethylstyrene-block-polystyrene diblock copolymer (PPySt-b-PSt. Micellization occurred by electron transfer from the pyridine to the photo-acid generator in their excited states and provided monodispersed spherical micelles with cores of PPySt blocks. Further, the photo-Claisen rearrangement caused the micellization of poly(4-allyloxystyrene-block-polystyrene diblock copolymer (PASt-b-PSt. Micellization was promoted in cyclohexane at room temperature without a catalyst. During micellization, the elimination of the allyl groups competitively occurred along with the photorearrangement of the 4-allyloxystyrene units into the 3-allyl-4-hydroxystyrene units.

Fast & scalable pattern transfer via block copolymer nanolithography

DEFF Research Database (Denmark)

Li, Tao; Wang, Zhongli; Schulte, Lars

2015-01-01

A fully scalable and efficient pattern transfer process based on block copolymer (BCP) self-assembling directly on various substrates is demonstrated. PS-rich and PDMS-rich poly(styrene-b-dimethylsiloxane) (PS-b-PDMS) copolymers are used to give monolayer sphere morphology after spin-casting of s......A fully scalable and efficient pattern transfer process based on block copolymer (BCP) self-assembling directly on various substrates is demonstrated. PS-rich and PDMS-rich poly(styrene-b-dimethylsiloxane) (PS-b-PDMS) copolymers are used to give monolayer sphere morphology after spin...... on long range lateral order, including fabrication of substrates for catalysis, solar cells, sensors, ultrafiltration membranes and templating of semiconductors or metals....

21 CFR 177.1340 - Ethylene-methyl acrylate copolymer resins.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethylene-methyl acrylate copolymer resins. 177.1340... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1340 Ethylene-methyl acrylate copolymer resins. Ethylene-methyl acrylate copolymer resins may be safely used as articles or components of...

POLYCAPROLACTONE-POLY (ETHYLENE GLYCOL) BLOCK COPOLYMER Ⅲ DRUG RELEASE BEHAVIOR

Institute of Scientific and Technical Information of China (English)

BEI Jianzhong; WANG Zhifeng; WANG Shenguo

1995-01-01

The drug release behavior of degradable polymer - polycaprolactone-poly (ethylene glycol)block copolymer(PCE) in vitro was investigated by using 5-Fluoro-uracil (5-Fu) as a model drug under a condition of pH 7.4 at 37℃. It is found that the release rate of 5-Fu from PCE increased with increasing polyether content of the copolymer. The results show that the increasing polyether content of the copolymer caused increasing hydrophilicity and decreasing crystallinity of the PCE copolymer. Thus, the drug release behavior and the degradable property of the PCE can be controlled by adjusting the composition of the copolymer.

Nanostructured Polysulfone-Based Block Copolymer Membranes

KAUST Repository

Xie, Yihui

2016-05-01

The aim of this work is to fabricate nanostructured membranes from polysulfone-based block copolymers through self-assembly and non-solvent induced phase separation. Block copolymers containing polysulfone are novel materials for this purpose providing better mechanical and thermal stability to membranes than polystyrene-based copolymers, which have been exclusively used now. Firstly, we synthesized a triblock copolymer, poly(tert-butyl acrylate)-b-polsulfone-b-poly(tert-butyl acrylate) through polycondensation and reversible addition-fragmentation chain-transfer polymerization. The obtained membrane has a highly porous interconnected skin layer composed of elongated micelles with a flower-like arrangement, on top of the graded finger-like macrovoids. Membrane surface hydrolysis was carried out in a combination with metal complexation to obtain metal-chelated membranes. The copper-containing membrane showed improved antibacterial capability. Secondly, a poly(acrylic acid)-b-polysulfone-b-poly(acrylic acid) triblock copolymer obtained by hydrolyzing poly(tert-butyl acrylate)-b-polsulfone-b-poly(tert-butyl acrylate) formed a thin film with cylindrical poly(acrylic acid) microdomains in polysulfone matrix through thermal annealing. A phase inversion membrane was prepared from the same polymer via self-assembly and chelation-assisted non-solvent induced phase separation. The spherical micelles pre-formed in a selective solvent mixture packed into an ordered lattice in aid of metal-poly(acrylic acid) complexation. The space between micelles was filled with poly(acrylic acid)-metal complexes acting as potential water channels. The silver0 nanoparticle-decorated membrane was obtained by surface reduction, having three distinct layers with different particle sizes. Other amphiphilic copolymers containing polysulfone and water-soluble segments such as poly(ethylene glycol) and poly(N-isopropylacrylamide) were also synthesized through coupling reaction and copper0-mediated

Purification of SUMO conjugating enzymes and kinetic analysis of substrate conjugation

Science.gov (United States)

Yunus, Ali A.; Lima, Christopher D.

2009-01-01

SUMO conjugation to protein substrates requires the concerted action of a dedicated E2 ubiquitin conjugation enzyme (Ubc9) and associated E3 ligases. Although Ubc9 can directly recognize and modify substrate lysine residues that occur within a consensus site for SUMO modification, E3 ligases can redirect specificity and enhance conjugation rates during SUMO conjugation in vitro and in vivo. In this chapter, we will describe methods utilized to purify SUMO conjugating enzymes and model substrates which can be used for analysis of SUMO conjugation in vitro. We will also describe methods to extract kinetic parameters during E3-dependent or E3-independent substrate conjugation. PMID:19107417

Conjugation of Lectin to Poly(ε-caprolactone-block-glycopolymer Micelles for In Vitro Intravesical Drug Delivery

Directory of Open Access Journals (Sweden)

Ning Ning Li

2016-10-01

Full Text Available Amphiphilic poly(ε-caprolactone-block-poly[2-(α-d-mannopyranosyloxy ethyl acrylamide] (PCL-b-PManEA block copolymers were synthesized via a combination of ring-opening polymerization (ROP, reversible addition-fragmentation chain transfer (RAFT polymerization and reactive ester-amine reaction. The PCL-b-PManEA block copolymers can self-assemble into micelles and encapsulate anticancer drug doxorubicin (DOX. To enhance mucoadhesive property of the resulting DOX-loaded PCL-b-PManEA micelles, Concanavalin A (ConA lectin was further conjugated with the micelles. Turbidimetric assay using mucin shows that the DOX-loaded PCL-b-PManEA@ConA micelles are mucoadhesive. DOX release from the DOX-loaded PCL-b-PManEA@ConA micelles in artificial urine at 37 °C exhibits an initial burst release, followed by a sustained and slow release over three days. Confocal laser scanning microscope (CLSM images indicate that the DOX-loaded PCL-b-PManEA@ConA micelles can be effectively internalized by UMUC3 human urothelial carcinoma cells. The DOX-loaded PCL-b-PManEA@ConA micelles exhibit significant cytotoxicity to these cells.

Research Update: Triblock copolymers as templates to synthesize inorganic nanoporous materials

Directory of Open Access Journals (Sweden)

Yunqi Li

2016-04-01

Full Text Available This review focuses on the application of triblock copolymers as designed templates to synthesize nanoporous materials with various compositions. Asymmetric triblock copolymers have several advantages compared with symmetric triblock copolymers and diblock copolymers, because the presence of three distinct domains can provide more functional features to direct the resultant nanoporous materials. Here we clearly describe significant contributions of asymmetric triblock copolymers, especially polystyrene-block-poly(2-vinylpyridine-block-poly(ethylene oxide (abbreviated as PS-b-P2VP-b-PEO.

Amphiphilic brushes from metallo-supramolecular block copolymers

NARCIS (Netherlands)

Guillet, P.; Fustin, C.A.; Wouters, D.; Höppener, S.; Schubert, U.S.; Gohy, J.M.W.

2009-01-01

A novel strategy to control the formation of amphiphilic brushes from metallo-supramol. block copolymers is described. The investigated copolymer consists of a polystyrene block linked to a poly(ethylene oxide) one via a charged bis-terpyridine ruthenium(ii) complex (PS-[Ru]-PEO). The initial

Iodinated glycidyl methacrylate copolymer as a radiopaque material for biomedical applications.

Science.gov (United States)

Dawlee, S; Jayabalan, M

2013-07-01

Polymeric biomaterial was synthesized by copolymerizing 50:50 mol% of monomers, glycidyl methacrylate and methyl methacrylate. Iodine atoms were then grafted to the epoxide groups of glycidyl methacrylate units, rendering the copolymer radiopaque. The percentage weight of iodine in the present copolymer was found to be as high as 23%. The iodinated copolymer showed higher glass transition temperature and thermal stability in comparison with unmodified polymer. Radiographic analysis showed that the copolymer possessed excellent radiopacity. The iodinated copolymer was cytocompatible to L929 mouse fibroblast cells. The in vivo toxicological evaluation by intracutaneous reactivity test of the copolymer extracts has revealed that the material was nontoxic. Subcutaneous implantation of iodinated copolymer in rats has shown that the material was well tolerated. Upon explantation and histological examination, no hemorrhage, infection or necrosis was observed. The samples were found to be surrounded by a vascularized capsule consisting of connective tissue cells. The results indicate that the iodinated copolymer is biocompatible and may have suitable applications as implantable materials.

Controlling block copolymer phase behavior using ionic surfactant

Energy Technology Data Exchange (ETDEWEB)

Ray, D.; Aswal, V. K. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085, India E-mail: debes.phys@gmail.com (India)

2016-05-23

The phase behavior of poly(ethylene oxide)-poly(propylene oxide-poly(ethylene oxide) PEO-PPO-PEO triblock copolymer [P85 (EO{sub 26}PO{sub 39}EO{sub 26})] in presence of anionic surfactant sodium dodecyl sulfate (SDS) in aqueous solution as a function of temperature has been studied using dynamic light scattering (DLS) and small-angle neutron scattering (SANS). The measurements have been carried out for fixed concentrations (1 wt%) of block copolymer and surfactants. Each of the individual components (block copolymer and surfactant) and the nanoparticle–surfactant mixed system have been examined at varying temperature. The block copolymer P85 forms spherical micelles at room temperature whereas shows sphere-to-rod like micelle transition at higher temperatures. On the other hand, SDS surfactant forms ellipsoidal micelles over a wide temperature range. Interestingly, it is found that phase behavior of mixed micellar system (P85 + SDS) as a function of temperature is drastically different from that of P85, giving the control over the temperature-dependent phase behavior of block copolymers.

78 FR 20032 - Styrene-Ethylene-Propylene Block Copolymer; Tolerance Exemption

Science.gov (United States)

2013-04-03

...-Ethylene-Propylene Block Copolymer; Tolerance Exemption AGENCY: Environmental Protection Agency (EPA... for residues of styrene-ethylene-propylene block copolymer (CAS Reg. No. 108388-87-0) when used as an...-ethylene-propylene block copolymer on food or feed commodities. DATES: This regulation is effective April 3...

Polyethylene-Based Tadpole Copolymers

KAUST Repository

Alkayal, Nazeeha

2017-02-15

Novel well-defined polyethylene-based tadpole copolymers ((c-PE)-b-PS, PE: polyethylene, PS: polystyrene) with ring PE head and linear PS tail are synthesized by combining polyhomologation, atom transfer radical polymerization (ATRP), and Glaser coupling reaction. The -OH groups of the 3-miktoarm star copolymers (PE-OH)-b-PS, synthesized by polyhomologation and ATRP, are transformed to alkyne groups by esterification with propiolic acid, followed by Glaser cyclization and removal of the unreacted linear with Merrifield\\'s resin-azide. The characterization results of intermediates and final products by high-temperature size exclusion chromatography, H NMR spectroscopy, and differential scanning calorimetry confirm the tadpole topology.

Polyamide copolymers having 2,5-furan dicarboxamide units

Science.gov (United States)

Chisholm, Bret Ja; Samanta, Satyabrata

2017-09-19

Polyamide copolymers, and methods of making and using polyamide copolymers, having 2,5-furan dicarboxamide units are disclosed herein. Such polymers can be useful for engineering thermoplastics having advantageous physical and/or chemical properties.

Dynamic photoinduced realignment processes in photoresponsive block copolymer films: effects of the chain length and block copolymer architecture.

Science.gov (United States)

Sano, Masami; Shan, Feng; Hara, Mitsuo; Nagano, Shusaku; Shinohara, Yuya; Amemiya, Yoshiyuki; Seki, Takahiro

2015-08-07

A series of block copolymers composed of an amorphous poly(butyl methacrylate) (PBMA) block connected with an azobenzene (Az)-containing liquid crystalline (PAz) block were synthesized by changing the chain length and polymer architecture. With these block copolymer films, the dynamic realignment process of microphase separated (MPS) cylinder arrays of PBMA in the PAz matrix induced by irradiation with linearly polarized light was studied by UV-visible absorption spectroscopy, and time-resolved grazing incidence small angle X-ray scattering (GI-SAXS) measurements using a synchrotron beam. Unexpectedly, the change in the chain length hardly affected the realignment rate. In contrast, the architecture of the AB-type diblock or the ABA-type triblock essentially altered the realignment feature. The strongly cooperative motion with an induction period before realignment was characteristic only for the diblock copolymer series, and the LPL-induced alignment change immediately started for triblock copolymers and the PAz homopolymer. Additionally, a marked acceleration in the photoinduced dynamic motions was unveiled in comparison with a thermal randomization process.

21 CFR 177.1020 - Acrylonitrile/butadiene/sty-rene co-polymer.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Acrylonitrile/butadiene/sty-rene co-polymer. 177... SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances.../butadiene/sty-rene co-polymer. Acrylonitrile/butadiene/styrene copolymer identified in this section may be...

Renewable Pentablock Copolymers Containing Bulky Natural Rosin for Tough Bioplastics

Science.gov (United States)

Rahman, Md Anisur; Ganewatta, Mitra S.; Lokupitiya, Hasala N.; Liang, Yuan; Stefik, Morgan; Tang, Chuanbing

Renewable polymers have received significant attention due to environmental concerns on petrochemical counterparts. One of the most abundant natural biomass is resin acids. However, most polymers derived from resin acids are low molecular weight and brittle because of the high chain entanglement molecular weight resulted from the bulky hydrophenanthrene pendant group. It is well established that the brittleness can be overcome by synthesizing multi-block copolymers with low entanglement molecular weight components. We investigated the effects of chain architecture and microdomain orientation on mechanical properties of both tri and pentablock copolymers. We synthesized rosin-containing A-B-A-B-A type pentablock and A-B-A type triblock copolymers to improve their mechanical properties. Pentablock copolymers showed higher strength and better toughness as compared to triblock copolymers, both superior to homopolymers. The greater toughness of pentablock copolymers is due to the presence of the rosin based midblock chains that act as bridging chains between two polynorbornene blocks.

Ion Transport in Nanostructured Block Copolymer/Ionic Liquid Membranes

OpenAIRE

Hoarfrost, Megan Lane

2012-01-01

Incorporating an ionic liquid into one block copolymer microphase provides a platform for combining the outstanding electrochemical properties of ionic liquids with a number of favorable attributes provided by block copolymers. In particular, block copolymers thermodynamically self-assemble into well-ordered nanostructures, which can be engineered to provide a durable mechanical scaffold and template the ionic liquid into continuous ion-conducting nanochannels. Understanding how the additio...

Poly(ortho-phenylenediamine-co-aniline) based copolymer with improved capacitance

Science.gov (United States)

Olmedo-Martínez, Jorge L.; Farías-Mancilla, Bárbara I.; Vega-Rios, Alejandro; Zaragoza-Contreras, E. Armando

2017-10-01

A poly(ortho-phenylenediamine-co-aniline) copolymer is synthesized via the oxidative route, using a 1:1 M ratio of aniline to ortho-phenylenediamine (oPDA) and ammonium persulfate as the oxidizing agent. Infrared spectroscopy indicates that the copolymer contains the functional groups typically present in polyaniline and poly(ortho-phenylenediamine); whereas UV-vis-NIR spectroscopy shows that the copolymer adopts a phenazine-type structure. Cyclic voltammetry evidences the copolymer synthesis, as a redox peak at -65 mV, different from those exhibited by polyaniline (160 mV and 600 mV) or poly(o-phenylenediamine) (-240 mV) is observed. Finally, electrochemical impedance spectroscopy and the charge/discharge test provide support to propose the copolymer application in electrodes for supercapacitors.

Bactericidal and Hemocompatible Coating via the Mixed-Charged Copolymer.

Science.gov (United States)

Fan, Xiao-Li; Hu, Mi; Qin, Zhi-Hui; Wang, Jing; Chen, Xia-Chao; Lei, Wen-Xi; Ye, Wan-Ying; Jin, Qiao; Ren, Ke-Feng; Ji, Jian

2018-03-28

Cationic antibacterial coating based on quaternary ammonium compounds, with an efficient and broad spectrum bactericidal property, has been widely used in various fields. However, the high density of positive charges tends to induce weak hemocompatibility, which hinders the application of the cationic antibacterial coating in blood-contacting devices and implants. It has been reported that a negatively charged surface can reduce blood coagulation, showing improved hemocompatibility. Here, we describe a strategy to combine the cationic and anionic groups by using mixed-charged copolymers. The copolymers of poly (quaternized vinyl pyridine- co- n-butyl methacrylate- co-methacrylate acid) [P(QVP- co- nBMA- co-MAA)] were synthesized through free radical copolymerization. The cationic group of QVP, the anionic group of MAA, and the hydrophobic group of nBMA were designed to provide bactericidal capability, hemocompatibility, and coating stability, respectively. Our findings show that the hydrophilicity of the copolymer coating increased, and its zeta potential decreased from positive charge to negative charge with the increase of the anionic/cationic ratio. Meanwhile, the bactericidal property of the copolymer coating was kept around a similar level compared with the pure quaternary ammonium copolymer coating. Furthermore, the coagulation time, platelet adhesion, and hemolysis tests revealed that the hemocompatibility of the copolymer coating improved with the addition of the anionic group. The mixed-charged copolymer combined both bactericidal property and hemocompatibility and has a promising potential in blood-contacting antibacterial devices and implants.

Platinated DNA oligonucleotides: new probes forming ultrastable conjugates with graphene oxide

Science.gov (United States)

Wang, Feng; Liu, Juewen

2014-05-01

Metal containing polymers have expanded the property of polymers by involving covalently associated metal complexes. DNA is a special block copolymer. While metal ions are known to influence DNA, little is explored on its polymer property when strong metal complexes are associated. In this work, we study cisplatin modified DNA as a new polymer and probe. Out of the complexes formed between cisplatin-A15, HAuCl4-A15, Hg2+-T15 and Ag+-C15, only the cisplatin adduct is stable under the denaturing gel electrophoresis condition. Each Pt-nucleobase bond gives a positive charge and thus makes DNA a zwitterionic polymer. This allows ultrafast adsorption of DNA by graphene oxide (GO) and the adsorbed complex is highly stable. Non-specific DNA, protein, surfactants and thiolated compounds cannot displace platinated DNA from GO, while non-modified DNA is easily displaced in most cases. The stable GO/DNA conjugate is further tested for surface hybridization. This is the first demonstration of using metallated DNA as a polymeric material for interfacing with nanoscale materials.Metal containing polymers have expanded the property of polymers by involving covalently associated metal complexes. DNA is a special block copolymer. While metal ions are known to influence DNA, little is explored on its polymer property when strong metal complexes are associated. In this work, we study cisplatin modified DNA as a new polymer and probe. Out of the complexes formed between cisplatin-A15, HAuCl4-A15, Hg2+-T15 and Ag+-C15, only the cisplatin adduct is stable under the denaturing gel electrophoresis condition. Each Pt-nucleobase bond gives a positive charge and thus makes DNA a zwitterionic polymer. This allows ultrafast adsorption of DNA by graphene oxide (GO) and the adsorbed complex is highly stable. Non-specific DNA, protein, surfactants and thiolated compounds cannot displace platinated DNA from GO, while non-modified DNA is easily displaced in most cases. The stable GO/DNA conjugate

SYNTHESIS OF STYRENE-METHYL METHACRYLATE BLOCK COPOLYMER BY POLYAZOAMIDE AS INITIATOR

Institute of Scientific and Technical Information of China (English)

WANG Zhongyi; WEI Jeqing

1996-01-01

Polyazoamide(PAA) was used as initiator to prepare block copolymer P(MMA-b-St) by free radical polymerization. The fraction of block copolymer was about 50%. The structure of the block-copolymer was characterized by IR and the results of 1H-NMR and GPC showed that the content of the block and the molecular weight (-Mw) of the prepolymer and block copolymer could be controlled by varying the mol ratio of styrene/PAA and MMA/prepolymer. DSC and TEM results revealed that the block copolymer has two separated glass transition temperatures and phase separation within the domain structure.

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...

21 CFR 177.1570 - Poly-1-butene resins and butene/ethylene copolymers.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Poly-1-butene resins and butene/ethylene copolymers... resins and butene/ethylene copolymers. The poly-1-butene resins and butene/ethylene copolymers identified... the catalytic polymerization of 1-butene liquid monomer. Butene/ethylene copolymers are produced by...

Co-polymer Films for Sensors

Science.gov (United States)

Ryan, Margaret A. (Inventor); Jewell, April D. (Inventor); Taylor, Charles (Inventor); Yen, Shiao-Pin S. (Inventor); Kisor, Adam (Inventor); Manatt, Kenneth S. (Inventor); Blanco, Mario (Inventor); Goddard, William A. (Inventor); Homer, Margie L. (Inventor); Shevade, Abhijit V. (Inventor)

2012-01-01

Embodiments include a sensor comprising a co-polymer, the co-polymer comprising a first monomer and a second monomer. For some embodiments, the first monomer is poly-4-vinyl pyridine, and the second monomer is poly-4-vinyl pyridinium propylamine chloride. For some embodiments, the first monomer is polystyrene and the second monomer is poly-2-vinyl pyridinium propylamine chloride. For some embodiments, the first monomer is poly-4-vinyl pyridine, and the second monomer is poly-4-vinyl pyridinium benzylamine chloride. Other embodiments are described and claimed.

Boosting Up Performance of Inverted Photovoltaic Cells from Bis(alkylthien-2-yl)dithieno[2,3-d:2',3'-d']benzo[1,2-b:4',5'-b']di thiophene-Based Copolymers by Advantageous Vertical Phase Separation.

Science.gov (United States)

Guo, Pengzhi; Luo, Guoping; Su, Qiang; Li, Jianfeng; Zhang, Peng; Tong, Junfeng; Yang, Chunyan; Xia, Yangjun; Wu, Hongbin

2017-03-29

The photovoltaic cells (PVCs) from conjugated copolymers of PDTBDT-BT and PDTBDT-FBT with 5,10-bis(4,5-didecylthien-2-yl)dithieno[2,3-d:2',3'-d']benzo[1,2-b:4,5-b']dithiophene as electron donor moieties and benzothiadiazole and/or 5,6-difluorobenzothiadiazole as electron acceptor moieties are optimized by employing alcohol-soluble PFN (poly(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)) as cathode modification interlayer. The power conversion efficiencies (PCEs) of inverted PVCs (i-PVCs) from PDTBDT-BT and PDTBDT-FBT with devices configuration as ITO/PFN/active layer/MoO 3 /Ag are increased from 4.97% to 8.54% and 5.92% to 8.74%, in contrast to those for the regular PVCs (r-PVCs) with devices configuration as ITO/PEDOT:PSS/active layer/Ca/Al under 100 mW/cm 2 AM 1.5 illumination. The optical modeling calculations and X-ray photoelectron spectroscopy (XPS) investigations reveal that the r-PVCs and i-PVCs from the copolymers exhibit similar light harvesting characteristics, and the enhancements of the PCEs of the i-PVCs from the copolymers are mainly contributed to the favorable vertical phase separation as the strongly polymer-enriched top surface layers and slightly PC 71 BM (phenyl-C 71 -butyric acid methyl ester)-enriched bottom surface layers are correspondingly connected to the anodes and cathodes of the i-PVCs, while they are opposite in the r-PVCs. As we known, it is the first time to experimentally verify that the i-PVCs with alcohol-soluble conjugated polymers cathode modification layers enjoy favorable vertical phase separation.

21 CFR 177.1360 - Ethylene-vinyl acetate-vinyl alcohol copolymers.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethylene-vinyl acetate-vinyl alcohol copolymers... for Use as Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1360 Ethylene-vinyl acetate-vinyl alcohol copolymers. Ethylene-vinyl acetate-vinyl alcohol copolymers (CAS Reg. No. 26221-27-2...

Functionalization of Block Copolymer Vesicle Surfaces

Directory of Open Access Journals (Sweden)

Wolfgang Meier

2011-01-01

Full Text Available In dilute aqueous solutions certain amphiphilic block copolymers self-assemble into vesicles that enclose a small pool of water with a membrane. Such polymersomes have promising applications ranging from targeted drug-delivery devices, to biosensors, and nanoreactors. Interactions between block copolymer membranes and their surroundings are important factors that determine their potential biomedical applications. Such interactions are influenced predominantly by the membrane surface. We review methods to functionalize block copolymer vesicle surfaces by chemical means with ligands such as antibodies, adhesion moieties, enzymes, carbohydrates and fluorophores. Furthermore, surface-functionalization can be achieved by self-assembly of polymers that carry ligands at their chain ends or in their hydrophilic blocks. While this review focuses on the strategies to functionalize vesicle surfaces, the applications realized by, and envisioned for, such functional polymersomes are also highlighted.

Sorption of Aromatic Compounds with Copolymer Sorbent Materials Containing β-Cyclodextrin

Directory of Open Access Journals (Sweden)

Lee D. Wilson

2011-08-01

Full Text Available Urethane copolymer sorbent materials that incorporate β-cyclodextrin (CD have been prepared and their sorption properties with chlorinated aromatic compounds (i.e., pentachlorophenol, 2,4-dichlorophenol and 2,4-dichlorophenoxy acetic acid have been evaluated. The sorption properties of granular activated carbon (GAC were similarly compared in aqueous solution at variable pH conditions. The sorbents displayed variable BET surface areas as follows: MDI-X copolymers (< 101 m2/g, CDI-X copolymers (< 101 m2/g, and granular activated carbon (GAC ~103 m2/g. The sorption capacities for the copolymers sorbents are listed in descending order, as follows: GAC > CDI-3 copolymer ≈ MDI-3 copolymer. The sorption capacity for the aromatic adsorbates with each sorbent are listed in descending order, as follows: 2,4-dichlorophenol > 2,4-dichlorophenoxy acetic acid > pentachlorophenol. In general, the differences in the sorption properties of the copolymer sorbents with the chlorinated organics were related to the following factors: (i surface area of the sorbent; (ii CD content and accessibility; and (iii and the chemical nature of the sorbent material.

Self-assembled Block Copolymer Membranes with Bioinspired Artificial Channels

KAUST Repository

Sutisna, Burhannudin

2018-04-01

Nature is an excellent design that inspires scientists to develop smart systems. In the realm of separation technology, biological membranes have been an ideal model for synthetic membranes due to their ultrahigh permeability, sharp selectivity, and stimuliresponse. In this research, fabrications of bioinspired membranes from block copolymers were studied. Membranes with isoporous morphology were mainly prepared using selfassembly and non-solvent induced phase separation (SNIPS). An effective method that can dramatically shorten the path for designing new isoporous membranes from block copolymers via SNIPS was first proposed by predetermining a trend line computed from the solvent properties, interactions and copolymer block sizes of previously-obtained successful systems. Application of the method to new copolymer systems and fundamental studies on the block copolymer self-assembly were performed. Furthermore, the manufacture of bioinspired membranes was explored using (1) poly(styrene-b-4-hydroxystyrene-b-styrene) (PS-b-PHS-b-PS), (2) poly(styrene-bbutadiene- b-styrene) (PS-b-PB-b-PS) and (3) poly(styrene-b-γ-benzyl-L-glutamate) (PSb- PBLG) copolymers via SNIPS. The structure formation was investigated using smallangle X-ray scattering (SAXS) and time-resolved grazing-Incidence SAXS. The PS-b- PHS-b-PS membranes showed preferential transport for proteins, presumably due to the hydrogen bond interactions within the channels, electrostatic attraction, and suitable pore dimension. Well-defined nanochannels with pore sizes of around 4 nm based on PS-b- PB-b-PS copolymers could serve as an excellent platform to fabricate bioinspired channels due to the modifiable butadiene blocks. Photolytic addition of thioglycolic acid was demonstrated without sacrificing the self-assembled morphology, which led to a five-fold increase in water permeance compared to that of the unmodified. Membranes with a unique feather-like structure and a lamellar morphology for dialysis and

Process of irradiating an ethylene-vinyl acetate copolymer to produce low melt index copolymers, and products of said process

International Nuclear Information System (INIS)

Potts, J.E.

1976-01-01

Application of ionizing radiation in a dose between 0.5 and 1.5 megareps to copolymers of ethylene and vinyl acetate lowers the melt index and increases the toughness and flexibility of the copolymers without substantially decreasing solubility or thermoplasticity. The increased toughness and flexibility carries over into blends with wax or polyethylene. (author)

Microbial production of polyhydroxyalkanoate block copolymer by recombinant Pseudomonas putida.

Science.gov (United States)

Li, Shi Yan; Dong, Cui Ling; Wang, Shen Yu; Ye, Hai Mu; Chen, Guo-Qiang

2011-04-01

Polyhydroxyalkanoate (PHA) synthesis genes phaPCJ(Ac) cloned from Aeromonas caviae were transformed into Pseudomonas putida KTOY06ΔC, a mutant of P. putida KT2442, resulting in the ability of the recombinant P. putida KTOY06ΔC (phaPCJ(A.c)) to produce a short-chain-length and medium-chain-length PHA block copolymer consisting of poly-3-hydroxybutyrate (PHB) as one block and random copolymer of 3-hydroxyvalerate (3HV) and 3-hydroxyheptanoate (3HHp) as another block. The novel block polymer was studied by differential scanning calorimetry (DSC), nuclear magnetic resonance, and rheology measurements. DSC studies showed the polymer to possess two glass transition temperatures (T(g)), one melting temperature (T(m)) and one cool crystallization temperature (T(c)). Rheology studies clearly indicated a polymer chain re-arrangement in the copolymer; these studies confirmed the polymer to be a block copolymer, with over 70 mol% homopolymer (PHB) of 3-hydroxybutyrate (3HB) as one block and around 30 mol% random copolymers of 3HV and 3HHp as the second block. The block copolymer was shown to have the highest tensile strength and Young's modulus compared with a random copolymer with similar ratio and a blend of homopolymers PHB and PHVHHp with similar ratio. Compared with other commercially available PHA including PHB, PHBV, PHBHHx, and P3HB4HB, the short-chain- and medium-chain-length block copolymer PHB-b-PHVHHp showed differences in terms of mechanical properties and should draw more attentions from the PHA research community. © Springer-Verlag 2010

Polyether based segmented copolymers with uniform aramid units

NARCIS (Netherlands)

Niesten, M.C.E.J.

2000-01-01

Segmented copolymers with short, glassy or crystalline hard segments and long, amorphous soft segments (multi-block copolymers) are thermoplastic elastomers (TPE’s). The hard segments form physical crosslinks for the amorphous (rubbery) soft segments. As a result, this type of materials combines

Study on immobilized yeast cells with hydrophilic polymer carrier by radiation-induced copolymerization

International Nuclear Information System (INIS)

Li Zhengkui; Zhang Bosen

1993-01-01

Various kinds of monomers 2-hydroxyethyl methacrylate (HEMA), 2-hydroxyethyl acrylate (HEA), hydroxypropyl methacrylate (HPMA) and methoxy polyethylene glycol methylacrylate (M-23G) are copolymerized by radiation technique at low temperature (-78 degree C) and several kinds of copolymer carriers were obtained. Yeast cells are immobilized through adhesion and multiplication of yeast cells themselves on these carriers. The ethanol productivity of immobilized yeast cells with these carriers was related to the monomer composition and water content of copolymer carriers and the optimum monomer composition was 20%:10% in poly (HEA-M23G). In this case, the ethanol productivity of immobilized yeast cells was 26 mg/(ml · h), which was 4 times as high as that of free cells. Effect of adding crosslinking reagent (4G) in lower monomer composition of poly(HEA-M23G) on the ethanol productivity of immobilized cells was better than that in higher one in this work

Preparation of Water-Soluble Homo and Copolymers of Bithiophene with 3,4-Ethylene Dioxythiophene and 3-Dodecylthiophene in Presence of Polystyrene Sulfonic Acid: Structure, Morphology, Thermal Stability

Directory of Open Access Journals (Sweden)

Bakhshali Massoumi

2015-04-01

Full Text Available Conductive polymers based on water-soluble polythiophenes were prepared. In this respect, alkylation reaction was carried out to synthesize the monomer 3-dodecylthiophene using 3-bromothiophene, bromododecane and magnesium. The monomer 2,2′-bithiophene was also prepared from 2-bromothiophene. Then, poly(2,2′-bithiophene, poly(3,4-ethylenedioxythiophene and poly(3-dodecylthiophene homopolymers were prepared at room temperature by successive chemical oxidation in the presence of polystyrene sulfonic acid and ammonium persulfate and water, as dopant, oxidant and solvent, respectively, under vigorous stirring. Under similar conditions, 2,2′-bithiophene copolymers with 3-dodecylthiophene and 3,4-ethylenedioxythiophene, copolymers with 3-dodecylthiophene were prepared at different molar ratios. To purify and dry the prepared polymers, dialysis tubs and freezing dry processes were applied. Structure of homo and copolymers were investigated by Fourier transform infrared (FTIR. Conjugated and planar structures of polymers were studied by Ultravoilet (UV-vis spectroscopy. The electrical conductivity of synthesized polymers was measured by four probe technique. The morphology and thermal stability of the products were studied using scanning electron microscopy (SEM, transmission electron microscopy (TEM and thermogravimetric analysis (TGA. Finally, solubility of homo and copolymers were tested in some organic solvents and water. Electro- activity of the prepared polymers was studied by cyclic voltammetry (CV on the glassy carbon (GC in LiClO4/CH3CN electrolyte solution and their electro-activity was confirmed. Electro-conductivity and electro-activity of homo and co polymers were low due topresence of polystyrene sulfonic acid which reduced the immobility of the polymers.

Synthesis and Characterization of Stimuli Responsive Block Copolymers, Self-Assembly Behavior and Applications

Energy Technology Data Exchange (ETDEWEB)

Determan, Michael Duane [Iowa State Univ., Ames, IA (United States)

2005-12-17

The central theme of this thesis work is to develop new block copolymer materials for biomedical applications. While there are many reports of stimuli-responsive amphiphilic [19-21] and crosslinked hydrogel materials [22], the development of an in situ gel forming, pH responsive pentablock copolymer is a novel contribution to the field, Figure 1.1 is a sketch of an ABCBA pentablock copolymer. The A blocks are cationic tertiary amine methacrylates blocked to a central Pluronic F127 triblock copolymer. In addition to the prerequisite synthetic and macromolecular characterization of these new materials, the self-assembled supramolecular structures formed by the pentablock were experimentally evaluated. This synthesis and characterization process serves to elucidate the important structure property relationships of these novel materials, The pH and temperature responsive behavior of the pentablock copolymer were explored especially with consideration towards injectable drug delivery applications. Future synthesis work will focus on enhancing and tuning the cell specific targeting of DNA/pentablock copolymer polyplexes. The specific goals of this research are: (1) Develop a synthetic route for gel forming pentablock block copolymers with pH and temperature sensitive properties. Synthesis of these novel copolymers is accomplished with ATRP, yielding low polydispersity and control of the block copolymer architecture. Well defined macromolecular characteristics are required to tailor the phase behavior of these materials. (2) Characterize relationship between the size and shape of pentablock copolymer micelles and gel structure and the pH and temperature of the copolymer solutions with SAXS, SANS and CryoTEM. (3) Evaluate the temperature and pH induced phase separation and macroscopic self-assembly phenomenon of the pentablock copolymer. (4) Utilize the knowledge gained from first three goals to design and formulate drug delivery formulations based on the multi

Inhomogeneity of block copolymers at the interface of an immiscible polymer blend

Science.gov (United States)

Ryu, Ji Ho; Kim, YongJoo; Lee, Won Bo

2018-04-01

We present the effects of structure and stiffness of block copolymers on the interfacial properties of an immiscible homopolymer blend. Diblock and two-arm grafted copolymers with variation in stiffness are modeled using coarse-grained molecular dynamics to compare the compatibilization efficiency, i.e., reduction of interfacial tension. Overall, grafted copolymers are located more compactly at the interface and show better compatibilization efficiency than diblock copolymers. In addition, an increase in the stiffness for one of the blocks of the diblock copolymers causes unusual inhomogeneous interfacial coverage due to bundle formation. However, an increase in the stiffness for one of blocks of the grafted copolymers prevents the bundle formation due to the branched chain. As a result, homogeneous interfacial coverage of homopolymer blends is realized with significant reduction of interfacial tension which makes grafted copolymer a better candidate for the compatibilizer of immiscible homopolymer blend.

Anhydric maleic functionalization and polyethylene glycol grafting of lactide-co-trimethylene carbonate copolymers

Energy Technology Data Exchange (ETDEWEB)

Díaz, A.; Valle, L.; Franco, L. del [Departament d' Enginyeria Química, Universitat Politècnica de Catalunya, Av. Diagonal 647, Barcelona E-08028 (Spain); Sarasua, J.R. [Department of Mining-Metallurgy Engineering and Materials Science, University of the Basque Country (UPV/EHU), Bilbao (Spain); Estrany, F. [Departament d' Enginyeria Química, Universitat Politècnica de Catalunya, Av. Diagonal 647, Barcelona E-08028 (Spain); Puiggalí, J., E-mail: Jordi.Puiggali@upc.es [Department of Mining-Metallurgy Engineering and Materials Science, University of the Basque Country (UPV/EHU), Bilbao (Spain)

2014-09-01

Lactide and trimethylene carbonate copolymers were successfully grafted with polyethylene glycol via previous functionalization with maleic anhydride and using N,N′-diisopropylcarbodiimide as condensing agent. Maleinization led to moderate polymer degradation. Specifically, the weight average molecular weight decreased from 36,200 to 30,200 g/mol for the copolymer having 20 mol% of trimethylene carbonate units. Copolymers were characterized by differential scanning calorimetry, thermogravimetry and X-ray diffraction. Morphology of spherulites and lamellar crystals was evaluated with optical and atomic force microscopies, respectively. The studied copolymers were able to crystallize despite the randomness caused by the trimethylene carbonate units and the lateral groups. Contact angle measurements indicated that PEG grafted copolymers were more hydrophilic than parent copolymers. This feature justified that enzymatic degradation in lipase medium and proliferation of both epithelial-like and fibroblast-like cells were enhanced. Grafted copolymers were appropriate to prepare regular drug loaded microspheres by the oil-in-water emulsion method. Triclosan release from loaded microspheres was evaluated in two media. - Highlights: • Pegylated copolymers of lactide and trimethylene carbonate have been synthesized. • Grafting with polyethylene glycol was able via maleic anhydride functionalization. • Drug-loaded microspheres could be prepared from new pegylated copolymers. • Hydrophilicity of lactide/trimethylene carbonate copolymers increased by pegylation. • New pegylated copolymers supported cell adhesion and proliferation.

Surface morphology of PS-PDMS diblock copolymer films

DEFF Research Database (Denmark)

Andersen, T.H.; Tougaard, S.; Larsen, N.B.

2001-01-01

Spin coated thin films (∼400 Å) of poly(styrene)–poly(dimethylsiloxane) (PS–PDMS) diblock copolymers have been investigated using X-ray Photoelectron Spectroscopy and Atomic Force Microscopy. Surface segregation of the poly(dimethylsiloxane) blocks was studied for five diblock copolymers which ra...

Reactivity Ratios for Organotin Copolymer Systems

Directory of Open Access Journals (Sweden)

Mohamed H. El-Newehy

2010-04-01

Full Text Available Di(tri-n-butyltin itaconate (DTBTI and monoethyl tributyltin fumarate (METBTF were synthesized as organotin monomers. The organotin monomers were copolymerized with styrene (ST and methyl methacrylate (MMA via a free radical polymerization technique. The overall conversion was kept low (£15% wt/wt for all studied samples and the copolymer composition was determined from tin analysis. The synthesized monomers and copolymers were characterized by elemental analysis, 1H- and 13C-NMR, and FTIR spectroscopy.

SANS and SAXS study of block copolymer/homopolymer mixtures

International Nuclear Information System (INIS)

Hasegawa, Hirokazu; Tanaka, Hideaki; Hashimoto, Takeji; Han, C.C.

1991-01-01

The lateral and vertical components of the radius of gyration for a single block copolymer chain and those of a single homopolymer chain in the lamellar microdomain space formed by a mixture of diblock copolymers and homopolymers were investigated by means of small-angle neutron scattering (SANS) and the microdomain structures by small-angle X-ray scattering (SAXS). The homopolymers whose molecular weights are much smaller than that of the corresponding chains of the block copolymers were used so that the homopolymers were uniformly solubilized in the corresponding microdomains. The SANS result suggests that the homopolymer chains in the microdomain space as well as the block copolymer chains are more compressed in the direction parallel to the interface and more stretched in the direction perpendicular to the interface than the corresponding unperturbed polymer chains with the same molecular weight. On increasing the volume fraction of the homopolymers the thickness of the lamellar microdomains increases. The block copolymer chains were found to undergo an isochoric affine deformation on addition of the homopolymers or with the change of the thickness of the lamellar microdomains. (orig.)

Slip-spring model of entangled rod-coil block copolymers

Science.gov (United States)

Wang, Muzhou; Likhtman, Alexei E.; Olsen, Bradley D.

2015-03-01

Understanding the dynamics of rod-coil block copolymers is important for optimal design of functional nanostructured materials for organic electronics and biomaterials. Recently, we proposed a reptation theory of entangled rod-coil block copolymers, predicting the relaxation mechanisms of activated reptation and arm retraction that slow rod-coil dynamics relative to coil and rod homopolymers, respectively. In this work, we introduce a coarse-grained slip-spring model of rod-coil block copolymers to further explore these mechanisms. First, parameters of the coarse-grained model are tuned to match previous molecular dynamics simulation results for coils, rods, and block copolymers. For activated reptation, rod-coil copolymers are shown to disfavor configurations where the rod occupies curved portions of the entanglement tube of randomly varying curvature created by the coil ends. The effect of these barriers on diffusion is quantitatively captured by considering one-dimensional motion along an entanglement tube with a rough free energy potential. Finally, we analyze the crossover between the two mechanisms. The resulting dynamics from both mechanisms acting in combination is faster than from each one individually.

In-situ fabrication of diketopyrrolopyrrole-carbazole-based conjugated polymer/TiO2 heterojunction for enhanced visible light photocatalysis

Science.gov (United States)

Yang, Long; Yu, Yuyan; Zhang, Jianling; Chen, Fu; Meng, Xiao; Qiu, Yong; Dan, Yi; Jiang, Long

2018-03-01

Aiming at developing highly efficient photocatalysts by broadening the light-harvesting region and suppressing photo-generated electron-hole recombination simultaneously, this work reports rational design and fabrication of donor-acceptor (D-A) conjugated polymer/TiO2 heterojunction catalyst with strong interfacial interactions by a facile in-situ thermal treatment. To expand the light-harvesting window, soluable conjugated copolymers with D-A architecture are prepared by Pd-mediated polycondensation of diketopyrrolopyrrole (DPP) and t-butoxycarbonyl (t-Boc) modified carbazole (Car), and used as visible-light-harvesting antenna to couple with TiO2 nanocrystals. The DPP-Car/TiO2 composites show wide range absorption in 300-1000 nm. To improve the interfacial binding at the interface, a facile in-situ thermal treatment is carried out to cleave the pendant t-Boc groups in carbazole units and liberate the polar amino groups (-NH-) which strongly bind to the surface of TiO2 through dipole-dipole interactions, forming a heterojunction interface. This in-situ thermal treatment changes the surface elemental distribution of TiO2, reinforces the interface bonding at the boundary of conjugated polymers/TiO2 and finally improves the photocatalytic efficiency of DPP-Car/TiO2 under visible-light irradiation. The interface changes are characterized and verified through Fourier-transform infrared spectroscopy (FT-IR), photo images, UV/Vis (solution state and powder diffuse reflection spectroscopy), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), fluorescence, scanning electron microscopy(SEM) and transmission electron microscopy (TEM) techniques. This study provides a new strategy to avoid the low solubility of D-A conjugated polymers and construct highly-efficient conjugated polymer/TiO2 heterojunction by enforcing the interface contact and facilitating charge or energy transfer for the applications in photocatalysis.

Sorption of Aromatic Compounds with Copolymer Sorbent Materials Containing β-Cyclodextrin.

Science.gov (United States)

Wilson, Lee D; Mohamed, Mohamed H; Berhaut, Christopher L

2011-08-29

Urethane copolymer sorbent materials that incorporate β-cyclodextrin (CD) have been prepared and their sorption properties with chlorinated aromatic compounds (i.e., pentachlorophenol, 2,4-dichlorophenol and 2,4-dichlorophenoxy acetic acid) have been evaluated. The sorption properties of granular activated carbon (GAC) were similarly compared in aqueous solution at variable pH conditions. The sorbents displayed variable BET surface areas as follows: MDI-X copolymers (granular activated carbon (GAC ~10³ m²/g). The sorption capacities for the copolymers sorbents are listed in descending order, as follows: GAC > CDI-3 copolymer ≈ MDI-3 copolymer. The sorption capacity for the aromatic adsorbates with each sorbent are listed in descending order, as follows: 2,4-dichlorophenol > 2,4-dichlorophenoxy acetic acid > pentachlorophenol. In general, the differences in the sorption properties of the copolymer sorbents with the chlorinated organics were related to the following factors: (i) surface area of the sorbent; (ii) CD content and accessibility; and (iii) and the chemical nature of the sorbent material.

Diblock Copolymer/Layered Silicate Nanocomposite Thin Film Stability

Science.gov (United States)

Limary, Ratchana; Green, Peter

2000-03-01

The stability of thin film symmetric diblock copolymers blended with layered silicate nanocomposites were examined using a combination of optical microscopy, atomic force microscopy (AFM), and X-ray diffraction (XRD). Two cases were examined PS-b-PMMA (polystyrene-b-polymethylacrylate) blended with montmorillonite stoichiometrically loaded with alkyl ammonium ions, OLS(S), and PS-b-PMMA blended with montmorillonite loaded with excess alkyl ammonium ions, OLS(E). XRD spectra show an increase in the gallery spacing of the OLSs, indicating that the copolymer chains have intercalated the layered silicates. AFM images reveal a distinct difference between the two nanocomposite thin films: regions in the vicinity of OLS(S) aggregates were depleted of material, while in the vicinity of OLS(E) aggregates, dewetting of the substrate occurred. We show that the stability of the copolymer/OLS nanocomposite films is determined by the enthalpic driving force associated with intercalation of the copolymer chains into the galleries of the modified OLS layers and by the substrate/organic modifier interactions.

Influence of Chirality in Ordered Block Copolymer Phases

Science.gov (United States)

Prasad, Ishan; Grason, Gregory

2015-03-01

Block copolymers are known to assemble into rich spectrum of ordered phases, with many complex phases driven by asymmetry in copolymer architecture. Despite decades of study, the influence of intrinsic chirality on equilibrium mesophase assembly of block copolymers is not well understood and largely unexplored. Self-consistent field theory has played a major role in prediction of physical properties of polymeric systems. Only recently, a polar orientational self-consistent field (oSCF) approach was adopted to model chiral BCP having a thermodynamic preference for cholesteric ordering in chiral segments. We implement oSCF theory for chiral nematic copolymers, where segment orientations are characterized by quadrupolar chiral interactions, and focus our study on the thermodynamic stability of bi-continuous network morphologies, and the transfer of molecular chirality to mesoscale chirality of networks. Unique photonic properties observed in butterfly wings have been attributed to presence of chiral single-gyroid networks, this has made it an attractive target for chiral metamaterial design.

Block copolymer-nanoparticle hybrid self-assembly

KAUST Repository

Hoheisel, Tobias N.; Hur, Kahyun; Wiesner, Ulrich B.

2015-01-01

© 2014 Published by Elsevier Ltd. Polymer-inorganic hybrid materials provide exciting opportunities as they may display favorable properties from both constituents that are desired in applications including catalysis and energy conversion and storage. For the preparation of hybrid materials with well-defined morphologies, block copolymer-directed nanoparticle hybrids present a particularly promising approach. As will be described in this review, once the fundamental characteristics for successful nanostructure formation at or close to the thermodynamic equilibrium of these nanocomposites are identified, the approach can be generalized to various materials classes. In addition to the discussion of recent materials developments based on the use of AB diblock copolymers as well as ABC triblock terpolymers, this review will therefore emphasize progress in the fundamental understanding of the underlying formation mechanisms of such hybrid materials. To this end, critical experiments for, as well as theoretical progress in the description of these nanostructured block copolymer-based hybrid materials will be discussed. Rather than providing a comprehensive overview, the review will emphasize work by the Wiesner group at Cornell University, US, on block copolymer-directed nanoparticle assemblies as well as their use in first potential application areas. The results provide powerful design criteria for wet-chemical synthesis methodologies for the generation of functional nanomaterials for applications ranging from microelectronics to catalysis to energy conversion and storage.

Position transitions of polymer-grafted nanoparticles in diblock-copolymer nanocomposites

Directory of Open Access Journals (Sweden)

2011-04-01

Full Text Available Self-assembly of block copolymer/nanoparticle blends has promising applications in the design and fabrication of novel functional nanomaterials. Precise control of the spatial positions of nanoparticles within block copolymer-based nanomaterials is crucial to achieve some special physical properties and functions. Here, we employ the self-consistent field method to theoretically investigate the self-assembly of polymer grafted-nanoparticles in a diblock copolymer. It is found that by varying the size and selectivity of nanoparticles, one can not only produce various self-assembled nanostructures but also modulate the spatial positions of the nanoparticles, either at the copolymer interfaces or in the center of one copolymer phase, within the nanostructures. A denser grafted polymer brush plays a role of shielding effect on nanoparticles and can position them into the center of one copolymer phase. The nanostructural transition we observed is dictated by the competition between entropy and enthalpy. On the basis of a number of simulations, two phase diagrams of self-assembled nanostructures are constructed. This study may be helpful for optimal design of advanced materials with desired nanostructures and enhanced performance.

Melt-processable, radiation cross-linkable E--CTFE copolymer compositions

International Nuclear Information System (INIS)

Robertson, A.B.; Schaffhauser, R.J.

1976-01-01

Melt-processable, radiation cross-linkable ethylene/chlorotrifluoroethylene copolymer compositions are provided which contain about 0.1 to 5 percent by weight of the copolymer of a radiation cross-linking promoter, about 0.01 to 5 percent by weight of an anti-oxidant and about 0.1 to 30 precent by weight of an acid scavenger. Such compositions do not give off odors when irradiated to cross-link the copolymer and do not develop bubbles after irradiation. 15 claims, no drawings

Patchy micelles based on coassembly of block copolymer chains and block copolymer brushes on silica particles.

Science.gov (United States)

Zhu, Shuzhe; Li, Zhan-Wei; Zhao, Hanying

2015-04-14

Patchy particles are a type of colloidal particles with one or more well-defined patches on the surfaces. The patchy particles with multiple compositions and functionalities have found wide applications from the fundamental studies to practical uses. In this research patchy micelles with thiol groups in the patches were prepared based on coassembly of free block copolymer chains and block copolymer brushes on silica particles. Thiol-terminated and cyanoisopropyl-capped polystyrene-block-poly(N-isopropylacrylamide) block copolymers (PS-b-PNIPAM-SH and PS-b-PNIPAM-CIP) were synthesized by reversible addition-fragmentation chain transfer polymerization and chemical modifications. Pyridyl disulfide-functionalized silica particles (SiO2-SS-Py) were prepared by four-step surface chemical reactions. PS-b-PNIPAM brushes on silica particles were prepared by thiol-disulfide exchange reaction between PS-b-PNIPAM-SH and SiO2-SS-Py. Surface micelles on silica particles were prepared by coassembly of PS-b-PNIPAM-CIP and block copolymer brushes. Upon cleavage of the surface micelles from silica particles, patchy micelles with thiol groups in the patches were obtained. Dynamic light scattering, transmission electron microscopy, and zeta-potential measurements demonstrate the preparation of patchy micelles. Gold nanoparticles can be anchored onto the patchy micelles through S-Au bonds, and asymmetric hybrid structures are formed. The thiol groups can be oxidized to disulfides, which results in directional assembly of the patchy micelles. The self-assembly behavior of the patchy micelles was studied experimentally and by computer simulation.

Controlling sub-microdomain structure in microphase-ordered block copolymers and their nanocomposites

Science.gov (United States)

Bowman, Michelle Kathleen

Block copolymers exhibit a wealth of morphologies that continue to find ubiquitous use in a diverse variety of mature and emergent (nano)technologies, such as photonic crystals, integrated circuits, pharmaceutical encapsulents, fuel cells and separation membranes. While numerous studies have explored the effects of molecular confinement on such copolymers, relatively few have examined the sub-microdomain structure that develops upon modification of copolymer molecular architecture or physical incorporation of nanoscale objects. This work will address two relevant topics in this vein: (i) bidisperse brushes formed by single block copolymer molecules and (ii) copolymer nanocomposites formed by addition of molecular or nanoscale additives. In the first case, an isomorphic series of asymmetric poly(styrene-b -isoprene-b-styrene) (S1IS2) triblock copolymers of systematically varied chain length has been synthesized from a parent SI diblock copolymer. Small-angle x-ray scattering, coupled with dynamic rheology and self-consistent field theory (SCFT), reveals that the progressively grown S2 block initially resides in the I-rich matrix and effectively reduces the copolymer incompatibility until a critical length is reached. At this length, the S2 block co-locates with the S1 block so that the two blocks generate a bidisperse brush (insofar as the S1 and S2 lengths differ). This single-molecule analog to binary block copolymer blends affords unique opportunities for materials design at sub-microdomain length scales and provides insight into the transition from diblock to triblock copolymer (and thermoplastic elastomeric nature). In the second case, I explore the distribution of molecular and nanoscale additives in microphase-ordered block copolymers and demonstrate via SCFT that an interfacial excess, which depends strongly on additive concentration, selectivity and relative size, develops. These predictions are in agreement with experimental findings. Moreover, using a

Responsive Copolymers for Enhanced Petroleum Recovery

Energy Technology Data Exchange (ETDEWEB)

McCormick, C.; Hester, R.

2001-02-27

The objectives of this work was to: synthesize responsive copolymer systems; characterize molecular structure and solution behavior; measure rheological properties of aqueous fluids in fixed geometry flow profiles; and to tailor final polymer compositions for in situ rheology control under simulated conditions. This report focuses on the synthesis and characterization of novel stimuli responsive copolymers, the investigation of dilute polymer solutions in extensional flow and the design of a rheometer capable of measuring very dilute aqueous polymer solutions at low torque.

Phase behavior of model ABC triblock copolymers

Science.gov (United States)

Chatterjee, Joon

The phase behavior of poly(isoprene-b-styrene- b-ethylene oxide) (ISO), a model ABC triblock copolymer has been studied. This class of materials exhibit self-assembly, forming a large array of ordered morphologies at length scales of 5-100 nm. The formation of stable three-dimensionally continuous network morphologies is of special interest in this study. Since these nanostructures considerably impact the material properties, fundamental knowledge for designing ABC systems have high technological importance for realizing applications in the areas of nanofabrication, nanoporous media, separation membranes, drug delivery and high surface area catalysts. A comprehensive framework was developed to describe the phase behavior of the ISO triblock copolymers at weak to intermediate segregation strengths spanning a wide range of composition. Phases were characterized through a combination of characterization techniques, including small angle x-ray scattering, dynamic mechanical spectroscopy, transmission electron microscopy, and birefringence measurements. Combined with previous investigations on ISO, six different stable ordered state symmetries have been identified: lamellae (LAM), Fddd orthorhombic network (O70), double gyroid (Q230), alternating gyroid (Q214), hexagonal (HEX), and body-centered cubic (BCC). The phase map was found to be somewhat asymmetric around the fI = fO isopleth. This work provides a guide for theoretical studies and gives insight into the intricate effects of various parameters on the self-assembly of ABC triblock copolymers. Experimental SAXS data evaluated with a simple scattering intensity model show that local mixing varies continuously across the phase map between states of two- and three-domain segregation. Strategies of blending homopolymers with ISO triblock copolymer were employed for studying the swelling properties of a lamellar state. Results demonstrate that lamellar domains swell or shrink depending upon the type of homopolymer that

Non-immunogenic, hydrophilic/cationic block copolymers and uses thereof

Science.gov (United States)

Scales, Charles W.; Huang, Faqing; McCormick, Charles L.

2010-05-18

The present invention provides novel non-immunogenic, hydrophilic/cationic block copolymers comprising a neutral-hydrophilic polymer and a cationic polymer, wherein both polymers have well-defined chain-end functionality. A representative example of such a block copolymer comprises poly(N-(2-hydroxypropyl)methacrylamide) (PHPMA) and poly(N-[3-(dimethylamino)propyl]methacrylamide) (PDMAPMA). Also provided is a synthesis method thereof in aqueous media via reversible addition fragmentation chain transfer (RAFT) polymerization. Further provided are uses of these block copolymers as drug delivery vehicles and protection agents.

Block copolymer morphologies confined by square-shaped particle: Hard and soft confinement

International Nuclear Information System (INIS)

Zhang Qiyi; Yang Wenyan; Hu Kaiyan

2016-01-01

The self-assembly of diblock copolymers confined around one square-shaped particle is studied systematically within two-dimensional self-consistent field theory (SCFT). In this model, we assume that the thin block copolymer film is confined in the vicinity of a square-shaped particle by a homopolymer melt, which is equivalent to the poor solvents. Multiple sequences of square-shaped particle-induced copolymer aggregates with different shapes and self-assembled internal morphologies are predicted as functions of the particle size, the structural portion of the copolymer, and the volume fraction of the copolymer. A rich variety of aggregates are found with complex internal self-assembled morphologies including complex structures of the vesicle, with one or several inverted micelle surrounded by the outer monolayer with the particle confined in the core. These results demonstrate that the assemblies of diblock copolymers formed around the square-shaped particle in poor solvents are of immediate interest to the assembly of copolymer and the morphology of biomembrane in the confined environment, as well as to the transitions of vesicles to micelles. (paper)

Topology and Shape Control for Assemblies of Block Copolymer Blends in Solution

KAUST Repository

Moreno Chaparro, Nicolas; Nunes, Suzana Pereira; Peinemann, Klaus-Viktor; Calo, Victor M.

2015-01-01

We study binary blends of asymmetric diblock copolymers (AB/AC) in selective solvents with a mesoscale model. We investigate the morphological transitions induced by the concentration of the AC block copolymer and the difference in molecular weight between the AB and AC copolymers, when segments B and C exhibit hydrogen-bonding interactions. To the best of our knowledge, this is the first work modeling mixtures of block copolymers with large differences in molecular weight. The coassembly mechanism localizes the AC molecules at the interface of A and B domains and induces the swelling of the B-rich domains. The coil size of the large molecular weight block copolymer depends only on the concentration of the short block copolymer (AC or AB), regardless of the B–C interactions. However, the B–C interactions control the morphological transitions that occur in these blends.

Topology and Shape Control for Assemblies of Block Copolymer Blends in Solution

KAUST Repository

Moreno Chaparro, Nicolas

2015-10-27

We study binary blends of asymmetric diblock copolymers (AB/AC) in selective solvents with a mesoscale model. We investigate the morphological transitions induced by the concentration of the AC block copolymer and the difference in molecular weight between the AB and AC copolymers, when segments B and C exhibit hydrogen-bonding interactions. To the best of our knowledge, this is the first work modeling mixtures of block copolymers with large differences in molecular weight. The coassembly mechanism localizes the AC molecules at the interface of A and B domains and induces the swelling of the B-rich domains. The coil size of the large molecular weight block copolymer depends only on the concentration of the short block copolymer (AC or AB), regardless of the B–C interactions. However, the B–C interactions control the morphological transitions that occur in these blends.

Singlet Exciton Lifetimes in Conjugated Polymer Films for Organic Solar Cells

KAUST Repository

Dimitrov, Stoichko

2016-01-13

The lifetime of singlet excitons in conjugated polymer films is a key factor taken into account during organic solar cell device optimization. It determines the singlet exciton diffusion lengths in polymer films and has a direct impact on the photocurrent generation by organic solar cell devices. However, very little is known about the material properties controlling the lifetimes of singlet excitons, with most of our knowledge originating from studies of small organic molecules. Herein, we provide a brief summary of the nature of the excited states in conjugated polymer films and then present an analysis of the singlet exciton lifetimes of 16 semiconducting polymers. The exciton lifetimes of seven of the studied polymers were measured using ultrafast transient absorption spectroscopy and compared to the lifetimes of seven of the most common photoactive polymers found in the literature. A plot of the logarithm of the rate of exciton decay vs. the polymer optical bandgap reveals a medium correlation between lifetime and bandgap, thus suggesting that the Energy Gap Law may be valid for these systems. This therefore suggests that small bandgap polymers can suffer from short exciton lifetimes, which may limit their performance in organic solar cell devices. In addition, the impact of film crystallinity on the exciton lifetime was assessed for a small bandgap diketopyrrolopyrrole co-polymer. It is observed that the increase of polymer film crystallinity leads to reduction in exciton lifetime and optical bandgap again in agreement with the Energy Gap Law.

Physical properties of metallocenes propene-higher α-olefins copolymers

International Nuclear Information System (INIS)

Lovisi, Humberto; Santa Maria, Luiz Claudio de; Coutinho, Fernanda M.B.

2001-01-01

In this work, new copolymers of propene/1-hexene (PHC) and propene/1-octene (POC) were synthesized by using a highly iso specific metallocenes catalyst system based on rac-Me 2 Si(2-ethyl,4-phenyl,1-indenyl) 2 ZrCl 2 , in the homogeneous and heterogeneous forms, methylaluminoxane (MAO) activated. An investigation about the copolymerization of propene with 1-hexene and 1-octene using this catalyst system illustrates the potential for the tailoring of propene/higher α-olefin copolymers with controlled thermal and mechanical properties by varying the comonomer concentration in the polymerization feed. Both catalyst systems showed high activity and produced random copolymers with very low or no detectable crystallinity. It was observed that properties such as enthalpy of crystallization (ΔHc), crystallization temperature (Tc), melting temperature (Tm), glass transition temperature (Tg) and elastic modulus (E') decreased in a linear pattern with increasing comonomer content in the copolymer. The effect of the short chain branch length was also investigated and it was observed that, compared to 1-hexene, much less 1-octene was necessary to disrupt the crystalline structure and impart rubbery behaviour to the copolymers. (author)

HPMA-based polymer therapeutics improve the efficacy of surgery, of radiotherapy and of chemotherapy combinations

Czech Academy of Sciences Publication Activity Database

Lammers, T.; Šubr, Vladimír; Ulbrich, Karel; Peschke, P.; Huber, P. E.; Hennink, W. E.; Storm, G.; Kiessling, F.

2010-01-01

Roč. 5, č. 10 (2010), s. 1501-1523 ISSN 1743-5889 R&D Projects: GA MŠk 1M0505 Institutional research plan: CEZ:AV0Z40500505 Keywords : N-(2-hydroxypropyl)methacrylamide copolymers * nanomedicine * drug delivery Subject RIV: EI - Biotechnology ; Bionics Impact factor: 6.202, year: 2010

Incorporation of fluconazole in copolymer PMMA-g-PEG derivatives

International Nuclear Information System (INIS)

Silveira, B.M.; Santos, V.M.R. dos; Novack, K.M.; Lopes, S.A.

2014-01-01

The graft copolymer PMMA-g-PEG went through chemical transformations in its chain through acetylation, halogenation, methylation and esterification followed by hydrolysis reactions. Subsequently, the copolymer PMMA-g-PEG derivatives passed through the process of emulsification and incorporation of the drug fluconazole. Derivatives copolymers were characterized by infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) after incorporation in order to evaluate their effectiveness. The efficiency of incorporation was observed and it was also verified that the complexity of polymer chain influence in the incorporated fluconazole content. (author)

Polyethylene-Based Tadpole Copolymers

KAUST Repository

Alkayal, Nazeeha; Zhang, Zhen; Bilalis, Panayiotis; Gnanou, Yves; Hadjichristidis, Nikolaos

2017-01-01

Novel well-defined polyethylene-based tadpole copolymers ((c-PE)-b-PS, PE: polyethylene, PS: polystyrene) with ring PE head and linear PS tail are synthesized by combining polyhomologation, atom transfer radical polymerization (ATRP), and Glaser

Morphologies of precise polyethylene-based acid copolymers and ionomers

Science.gov (United States)

Buitrago, C. Francisco

Acid copolymers and ionomers are polymers that contain a small fraction of covalently bound acidic or ionic groups, respectively. For the specific case of polyethylene (PE), acid and ionic pendants enhance many of the physical properties such as toughness, adhesion and rheological properties. These improved properties result from microphase separated aggregates of the polar pendants in the non-polar PE matrix. Despite the widespread industrial use of these materials, rigorous chemical structure---morphology---property relationships remain elusive due to the inevitable structural heterogeneities in the historically-available acid copolymers and ionomers. Recently, precise acid copolymers and ionomers were successfully synthesized by acyclic diene metathesis (ADMET) polymerization. These precise materials are linear, high molecular weight PEs with pendant acid or ionic functional groups separated by a precisely controlled number of carbon atoms. The morphologies of nine precise acid copolymers and eleven precise ionomers were investigated by X-ray scattering, solid-state 13C nuclear magnetic resonance (NMR) and differential scanning calorimetry (DSC). For comparison, the morphologies of linear PEs with pseudo-random placement of the pendant groups were also studied. Previous studies of precise copolymers with acrylic acid (AA) found that the microstructural precision produces a new morphology in which PE crystals drive the acid aggregates into layers perpendicular to the chain axes and presumably at the interface between crystalline and amorphous phases. In this dissertation, a second new morphology for acid copolymers is identified in which the aggregates arrange on cubic lattices. The fist report of a cubic morphology was observed at room and elevated temperatures for a copolymer functionalized with two phosphonic acid (PA) groups on every 21st carbon atom. The cubic lattice has been identified as face-centered cubic (FCC). Overall, three morphology types have been

Block coordination copolymers

Science.gov (United States)

Koh, Kyoung Moo; Wong-Foy, Antek G; Matzger, Adam J; Benin, Annabelle I; Willis, Richard R

2012-11-13

The present invention provides compositions of crystalline coordination copolymers wherein multiple organic molecules are assembled to produce porous framework materials with layered or core-shell structures. These materials are synthesized by sequential growth techniques such as the seed growth technique. In addition, the invention provides a simple procedure for controlling functionality.

Temperature effect on radiation induced reactions in ethylene and tetrafluoroethylene copolymer (ETFE)

International Nuclear Information System (INIS)

Oshima, Akihiro; Tabata, Yoneho; Ikeda, Shigetoshi; Seguchi, Tadao

1997-01-01

Ethylene and tetrafluoroethylene copolymer (ETFE) was irradiated by γ-rays or electron beam (EB) under oxygen-free atmosphere at various temperatures ranging from 77 to 573 K. Mechanical and thermal properties, and absorption spectra of the irradiated ETFEs were measured. The mechanical properties of the film have been observed to change by irradiation. The modulus and yield strength increase with increasing dose, and these phenomena are clearly distinguished above the melting temperature of ETFE (533 K). Heat of crystallization changes drastically as a function of irradiation dose around the melting , compared with other temperatures. The absorption band around 250 nm of irradiated ETFE shifts to a longer wavelength region with increase of irradiation temperature. Therefore, it was concluded from those experimental results mentioned above that crosslinking takes place and conjugated double bonds formation proceeds in a wide range of irradiation temperatures. Those reactions are enhanced by increasing temperature. The homogeneous crosslinking takes place in the molten state, while the heterogeneous crosslinking does in the crystalline solid state. (author)

About morphology in ethylene-propylene(-diene) copolymers-based latexes

NARCIS (Netherlands)

Tillier, D.L.; Meuldijk, J.; Hoehne, G.W.H.; Frederik, P.M.; Regev, O.; Koning, C.E.

2005-01-01

Coatings and engineering plastics often require high impact strength. This property can be achieved with tougheners. For the present paper, core-shell impact modifiers were synthesized using ethylene–propylene copolymers (EPM), ethylene–propylene-diene copolymers (EPDM) or a mixture of both types

Adsorption of charged diblock copolymers : effect on colloidal stability

NARCIS (Netherlands)

Israels, R.

1994-01-01

In this thesis we present Scheutjens-Fleer (SF) calculations on the adsorption of diblock copolymers. More specifically, we restrict ourselves to adsorption at uncharged surfaces, while the specific type of block copolymers we consider have one uncharged adsorbing "anchor" block and one

Monte Carlo simulations of the phase separation of a copolymer blend in a thin film

KAUST Repository

Wang, Zhexiao

2014-12-11

Monte Carlo simulations were carried out to study the phase separation of a copolymer blend comprising an alternating copolymer and/or block copolymer in a thin film, and a phase diagram was constructed with a series of composed recipes. The effects of composition and segregation strength on phase separation were discussed in detail. The chain conformation of the block copolymer and alternating copolymer were investigated with changes of the segregation strength. Our simulations revealed that the segment distribution along the copolymer chain and the segregation strength between coarse-grained beads are two important parameters controlling phase separation and chain conformation in thin films of a copolymer blend. A well-controlled phase separation in the copolymer blend can be used to fabricate novel nanostructures.

Mechanically compliant electrodes and dielectric elastomers from PEG-PDMS copolymers

DEFF Research Database (Denmark)

A Razak, Aliff Hisyam; Madsen, Frederikke Bahrt; Skov, Anne Ladegaard

2016-01-01

Soft conducting elastomers have been prepared from polydimethylsiloxane-polyethyleneglycol (PDMS-PEG) copolymer and surfactant-stabilized multi-walled carbon nanotubes (MWCNTs). The copolymer was chain-extended with PDMS of molecular weight 17.2 kg mol-1 in order to obtain a crosslinkable PDMS...... showed high conductivity combined with inherent softness. The high conductivity and softness, PDMS-PEG copolymers with incorporated MWCNTs hold great promises as compliant and highly stretchable electrodes for stretchable devices such as electro-mechanical transducers....

A Study on Copolymer Systems of Styrene with Diethanolamine Side Group and Methyl Methacrylate

Directory of Open Access Journals (Sweden)

Aslisah Acikses

2018-01-01

Full Text Available 4-Diethanolaminomethyl styrene (DEAMSt monomer was prepared by the modification of 4-chloromethyl styrene with diethanolamine. The copolymers in different combinations (0.11, 0.19, and 0.30 by mole of DEAMSt and methyl methacrylate (MMA were prepared by free radical polymerization method at 60°C in the presence of 1,4-dioxane and AIBN as initiator. The structures of DEAMSt and DEAMSt-MMA copolymer were characterized by FT-IR and 1H-NMR. The glass transition temperature (Tg of the copolymers was measured by DSC. Thermal decomposition behavior of the copolymers was investigated by TGA. The average molecular weights of the copolymers were determined by GPC. The dye uptaking properties of the copolymers were investigated using bromocresol green. Then, the dielectric constant, dielectric loss factor, and conductivity of copolymers were investigated as a function of temperature and frequency. The activation energies (Ea of the copolymers were determined by impedance analyzer.

Responsive copolymers for enhanced petroleum recovery. Second annual report

Energy Technology Data Exchange (ETDEWEB)

McCormick, C.; Hester, R.

1995-05-01

The authors describe second year efforts in synthesis, characterization, and rheology to develop polymers with significantly improved efficiency in mobility control and conformance. These advanced polymer systems would maintain high viscosities or behave as virtual gels under low shear conditions and at elevated electrolyte concentrations. At high fluid shear rates, associates would deaggregate yielding low viscosity solutions, reducing problems of shear degradation or face plugging during injection. Polymeric surfactants were also developed with potential for use in higher salt, higher temperature reservoirs for mobilization of entrapped oil. Chapters include: Ampholytic terpolymers of acrylamide with sodium 3-acrylamido-3-methylbutanoate and 2-acrylamido-2-methylpropanetrimethylammonium chloride; Hydrophilic sulfobetaine copolymers of acrylamide and 3-(2-acrylamido-methylpropane-dimethylammonio)-1-propanesulfonate; Copolymerization of maleic anhydride and N-vinylformamide; Reactivity ratio of N-vinylformamide with acrylamide, sodium acrylate, and n-butyl acrylate; Effect of the distribution of the hydrophobic cationic monomer dimethyldodecyl(2-acrylamidoethyl)ammonium bromide on the solution behavior of associating acrylamide copolymers; Effect of surfactants on the solution properties of amphipathic copolymers of acrylamide and N,N-dimethyl-N-dodecyl-N-(2-acrylamidoethyl)ammonium bromide; Associative interactions and photophysical behavior of amphiphilic terpolymers prepared by modification of maleic anhydride/ethyl vinyl ether copolymers; Copolymer compositions of high-molecular-weight functional acrylamido water-soluble polymers using direct-polarization magic-angle spinning {sup 13}C NMR; Use of factorial experimental design in static and dynamic light scattering characterization of water soluble polymers; and Porous medium elongational rheometer studies of NaAMB/AM copolymer solutions.

Preparation and icephobic properties of polymethyltrifluoropropylsiloxane–polyacrylate block copolymers

Energy Technology Data Exchange (ETDEWEB)

Li, Xiaohui; Zhao, Yunhui [School of Materials Science and Engineering, and Tianjin Key Laboratory of Composite and Functional Materials, Tianjin University, Tianjin 300072 (China); Li, Hui [School of Chemistry and Chemical Engineering, Shandong Key Laboratory of Fluorine Chemistry and Chemical Engineering Materials, University of Jinan, Jinan 250022 (China); Yuan, Xiaoyan, E-mail: xyuan28@yahoo.com [School of Materials Science and Engineering, and Tianjin Key Laboratory of Composite and Functional Materials, Tianjin University, Tianjin 300072 (China)

2014-10-15

Highlights: • PMTFPS–b-polyacrylate copolymers in five different compositions were synthesized. • Enrichment of PMTFPS amounts at the surface made high F/Si value. • Icing delay time was related to the surface roughness. • Ice shear strength was decreased by the synergistic effect of silicone and fluorine. - Abstract: Five polymethyltrifluoropropylsiloxane (PMTFPS)–polyacrylate block copolymers (PMTFPS–b-polyacrylate) were synthesized by free radical polymerization of methyl methacrylate, n-butyl acrylate and hydroxyethyl methacrylate using PMTFPS macroazoinitiator (PMTFPS-MAI) in range of 10–50 mass percentages. The morphology, surface chemical composition and wettability of the prepared copolymer films were investigated by transmission electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, and water contact angle measurement. Delayed icing time and ice shear strength of the films were also detected for the icephobic purpose. The surface morphologies of the copolymers were different from those of the bulk because of the migration of the PMTFPS segments to the air interface during the film formation. Maximal delayed icing time (186 s at −15 °C) and reduction of the ice shear strength (301 ± 10 kPa) which was significantly lower than that of polyacrylates (804 ± 37 kPa) were achieved when the content of PMTFPS-MAI was 20 wt%. The icephobicity of the copolymers was attributed primarily to the enrichment of PMTFPS on the film surface and synergistic effect of both silicone and fluorine. Thus, the results show that the PMTFPS–b-polyacrylate copolymer can be used as icephobic coating materials potentially.

Realization of an integrated VDF/TrFE copolymer-on-silicon pyroelectric sensor

NARCIS (Netherlands)

Setiadi, D.; Setiadi, D.; Regtien, Paulus P.L.; Sarro, P.M.

1995-01-01

An integrated pyroelectric sensor based on a vinylidene fluoride trifluoroethylene (VDF/TrFE) copolymer is presented. A silicon substrate that contains FET readout electronics is coated with the VDF/TrFE copolymer film using a spin-coating technique. On-chip poling of the copolymer has been applied

Rheological Behavior of Entangled Polystyrene-Polyhedral Oligosilsesquioxane (POSS) Copolymer

National Research Council Canada - National Science Library

Wu, Jian; Mather, Patrick T; Haddad, Timothy S; Kim, Gyeong-Man

2006-01-01

...: random copolymers of polystyrene (PS) and styryl-based polyhedral oligosilsesquioxane (POSS), R7(Si8O12)(C6H4CH=CH2), with R = isobutyl (iBu). A series of styrene-styryl POSS random copolymers with 0, 6, 15, 30, 50 wt...

Radiation crosslinked block copolymer blends with improved impact resistance

International Nuclear Information System (INIS)

Saunders, F.L.; Pelletier, R.R.

1976-01-01

Polymer blends having high impact resistance after mechanical working are produced by blending together a non-elastomeric monovinylidene aromatic polymer such as polystyrene with an elastomeric copolymer, such as a block copolymer of styrene and butadiene, in the form of crosslinked, colloidal size particles

Block copolymer battery separator

Science.gov (United States)

Wong, David; Balsara, Nitash Pervez

2016-04-26

The invention herein described is the use of a block copolymer/homopolymer blend for creating nanoporous materials for transport applications. Specifically, this is demonstrated by using the block copolymer poly(styrene-block-ethylene-block-styrene) (SES) and blending it with homopolymer polystyrene (PS). After blending the polymers, a film is cast, and the film is submerged in tetrahydrofuran, which removes the PS. This creates a nanoporous polymer film, whereby the holes are lined with PS. Control of morphology of the system is achieved by manipulating the amount of PS added and the relative size of the PS added. The porous nature of these films was demonstrated by measuring the ionic conductivity in a traditional battery electrolyte, 1M LiPF.sub.6 in EC/DEC (1:1 v/v) using AC impedance spectroscopy and comparing these results to commercially available battery separators.

Highly conductive side chain block copolymer anion exchange membranes.

Science.gov (United States)

Wang, Lizhu; Hickner, Michael A

2016-06-28

Block copolymers based on poly(styrene) having pendent trimethyl styrenylbutyl ammonium (with four carbon ring-ionic group alkyl linkers) or benzyltrimethyl ammonium groups with a methylene bridge between the ring and ionic group were synthesized by reversible addition-fragmentation radical (RAFT) polymerization as anion exchange membranes (AEMs). The C4 side chain polymer showed a 17% increase in Cl(-) conductivity of 33.7 mS cm(-1) compared to the benzyltrimethyl ammonium sample (28.9 mS cm(-1)) under the same conditions (IEC = 3.20 meq. g(-1), hydration number, λ = ∼7.0, cast from DMF/1-propanol (v/v = 3 : 1), relative humidity = 95%). As confirmed by small angle X-ray scattering (SAXS), the side chain block copolymers with tethered ammonium cations showed well-defined lamellar morphologies and a significant reduction in interdomain spacing compared to benzyltrimethyl ammonium containing block copolymers. The chemical stabilities of the block copolymers were evaluated under severe, accelerated conditions, and degradation was observed by (1)H NMR. The block copolymer with C4 side chain trimethyl styrenylbutyl ammonium motifs displayed slightly improved stability compared to that of a benzyltrimethyl ammonium-based AEM at 80 °C in 1 M NaOD aqueous solution for 30 days.

Poly(methacrylic acid-ran-2-vinylpyridine Statistical Copolymer and Derived Dual pH-Temperature Responsive Block Copolymers by Nitroxide-Mediated Polymerization

Directory of Open Access Journals (Sweden)

Milan Marić

2017-02-01

Full Text Available Nitroxide-mediated polymerization using the succinimidyl ester functional unimolecular alkoxyamine initiator (NHS-BlocBuilder was used to first copolymerize tert-butyl methacrylate/2-vinylpyridine (tBMA/2VP with low dispersity (Đ = 1.30–1.41 and controlled growth (linear number average molecular Mn versus conversion, Mn = 3.8–10.4 kg·mol−1 across a wide composition of ranges (initial mol fraction 2VP, f2VP,0 = 0.10–0.90. The resulting statistical copolymers were first de-protected to give statistical polyampholytic copolymers comprised of methacrylic acid/2VP (MAA/2VP units. These copolymers exhibited tunable water-solubility due to the different pKas of the acidic MAA and basic 2VP units; being soluble at very low pH < 3 and high pH > 8. One of the tBMA/2VP copolymers was used as a macroinitiator for a 4-acryloylmorpholine/4-acryloylpiperidine (4AM/4AP mixture, to provide a second block with thermo-responsive behavior with tunable cloud point temperature (CPT, depending on the ratio of 4AM:4AP. Dynamic light scattering of the block copolymer at various pHs (3, 7 and 10 as a function of temperature indicated a rapid increase in particle size >2000 nm at 22–27 °C, corresponding to the 4AM/4AP segment’s thermos-responsiveness followed by a leveling in particle size to about 500 nm at higher temperatures.

Fluorosilicone multi-block copolymers tethering quaternary ammonium salt groups for antimicrobial purpose

Energy Technology Data Exchange (ETDEWEB)

Zhou, Fang; Qin, Xiaoshuai; Li, Yancai; Ren, Lixia; Zhao, Yunhui, E-mail: zhaoyunhui@tju.edu.cn; Yuan, Xiaoyan

2015-08-30

Highlights: • QAS-containing fluorosilicone multi-block copolymers were synthesized. • The block length of PHFBMA in the copolymers was tailored via RAFT polymerization. • Surface roughness of the copolymers decreased with the increased PHFBMA content. • A certain length of PHFBMA block enhanced C−N{sup +} percentage on the surface. - Abstract: Symmetrically structured fluorosilicone multi-block copolymers containing poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) and poly(hexafluorobutyl methacrylate) (PHFBMA) were sequentially synthesized via reversible addition–fragmentation chain transfer polymerization, using a polydimethylsiloxane (PDMS) chain transfer agent with dithiocarbonate groups at both ends. Then, the CBABC-type block copolymers were quaternized with n-octyliodide to tether quaternary ammonium salt (QAS) groups in the PDMAEMA blocks for the antimicrobial use. The obtained fluorosilicone copolymers showed clear variations in the C-N{sup +} composition and surface morphology on their films depending on the content of the PHFBMA blocks, which were characterized by X-ray photoelectron spectroscopy and atomic force microscopy, respectively. The results indicated that the symmetrical CBABC structure favored PDMS and QAS tethered blocks migrating to the film surface. With the mass percentage of the PHFBMA increased from 0 to 32.5%, the surface roughness of the copolymer film decreased gradually with a tendency to form a smooth surface. Owing to the surface properties, fluorosilicone multi-block copolymers containing a certain amount of PHFBMA with higher C-N{sup +} content and relatively smooth morphology demonstrated obvious antimicrobial activity against Gram-positive bacteria, Bacillus subtilis and Gram-negative bacteria, Escherichia coli. The functionalized multi-block copolymers based on fluorosilicone and QAS groups would have potential applications in antimicrobial coatings.

Fluorosilicone multi-block copolymers tethering quaternary ammonium salt groups for antimicrobial purpose

International Nuclear Information System (INIS)

Zhou, Fang; Qin, Xiaoshuai; Li, Yancai; Ren, Lixia; Zhao, Yunhui; Yuan, Xiaoyan

2015-01-01

Highlights: • QAS-containing fluorosilicone multi-block copolymers were synthesized. • The block length of PHFBMA in the copolymers was tailored via RAFT polymerization. • Surface roughness of the copolymers decreased with the increased PHFBMA content. • A certain length of PHFBMA block enhanced C−N + percentage on the surface. - Abstract: Symmetrically structured fluorosilicone multi-block copolymers containing poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) and poly(hexafluorobutyl methacrylate) (PHFBMA) were sequentially synthesized via reversible addition–fragmentation chain transfer polymerization, using a polydimethylsiloxane (PDMS) chain transfer agent with dithiocarbonate groups at both ends. Then, the CBABC-type block copolymers were quaternized with n-octyliodide to tether quaternary ammonium salt (QAS) groups in the PDMAEMA blocks for the antimicrobial use. The obtained fluorosilicone copolymers showed clear variations in the C-N + composition and surface morphology on their films depending on the content of the PHFBMA blocks, which were characterized by X-ray photoelectron spectroscopy and atomic force microscopy, respectively. The results indicated that the symmetrical CBABC structure favored PDMS and QAS tethered blocks migrating to the film surface. With the mass percentage of the PHFBMA increased from 0 to 32.5%, the surface roughness of the copolymer film decreased gradually with a tendency to form a smooth surface. Owing to the surface properties, fluorosilicone multi-block copolymers containing a certain amount of PHFBMA with higher C-N + content and relatively smooth morphology demonstrated obvious antimicrobial activity against Gram-positive bacteria, Bacillus subtilis and Gram-negative bacteria, Escherichia coli. The functionalized multi-block copolymers based on fluorosilicone and QAS groups would have potential applications in antimicrobial coatings

Oriented Structure of Pentablock Copolymers Induced by Solution Extrusion

Science.gov (United States)

Harada, Tamotsu; Bates, Frank S.; Lodge, Timothy P.

2002-03-01

Highly oriented structure of a poly(styrene-co-butadiene) pentablock copolymer (Mw; 104,700 g/mol, weight percentage of polybutadiene blocks; 29 wt of concentrated solutions. The pentablock copolymer was dissolved into mixtures of toluene and heptane, and the polymer concentration ranged from 40 wt extrusion, the pentablock copolymer was solidified either by coagulation in methanol or by evaporation of the solvent. Interestingly, a highly oriented lamellar structure was confirmed through the small angle X-ray scattering over a specific range of heptane composition, which is a good solvent for polybutadiene, although the hexagonal cylinder morphology was identified for the melt sample. The transition from the oriented lamellar to highly oriented cylinder structure was observed by annealing the samples at temperatures above the glass transition temperature of polystyrene. Moreover, a transition from parallel to perpendicular orientation in the lamellar state was observed with an increase of the extrusion shear rate. A comparison between pentablock and triblock copolymers will be also discussed.

Resonant soft x-ray GISAXS on block copolymer films

Science.gov (United States)

Wang, Cheng; Araki, T.; Watts, B.; Ade, H.; Hexemer, A.; Park, S.; Russell, T. P.; Schlotter, W. F.; Stein, G. E.; Tang, C.; Kramer, E. J.

2008-03-01

Ordered block copolymer thin films may have important applications in modern device fabrication. Current characterization methods such as conventional GISAXS have fixed electron density contrast that can be overwhelmed by surface scattering. However, soft x-rays have longer wavelength, energy dependent contrast and tunable penetration, making resonant GISAXS a very promising tool for probing nanostructured polymer thin films. Our preliminary investigation was performed using PS-b-P2VP block copolymer films on beam-line 5-2 SSRL, and beam-line 6.3.2 at ALS, LBNL. The contrast/sensitivity of the scattering pattern varies significantly with photon energy close to the C K-edge (˜290 eV). Also, higher order peaks are readily observed, indicating hexagonal packing structure in the sample. Comparing to the hard x-ray GISAXS data of the same system, it is clear that resonant GISAXS has richer data and better resolution. Beyond the results on the A-B diblock copolymers, results on ABC block copolymers are especially interesting.

Modification of ethylene-norbornene copolymer by Gamma irradiation

Directory of Open Access Journals (Sweden)

Kačarević-Popović Zorica M.

2006-01-01

Full Text Available The possibility of modifying polyethylene and many other polymers with high energy radiation has led to many useful applications. Due to their new combination of properties and the shortage of experimental data, the radiolysis of a new class of materials, cyclo-olefin copolymers (COC, polymerised from norbornene and ethylene using metallocene catalysts, is of great interest to the study of radiation chemistry and the physics of polymeric systems. Ethylenenorbornene copolymer, pristine and containing an antioxidant were subjected to gamma irradiation in the presence of air and in water. The irradiated copolymer was studied using IR and UV-vis spectrophotometric analysis. The radiation-induced changes in the molecular structure were correlated to changes in the glass transition temperature measured by the DSC method.

ABC triblock copolymer vesicles with mesh-like morphology.

Science.gov (United States)

Zhao, Wei; Chen, Dian; Hu, Yunxia; Grason, Gregory M; Russell, Thomas P

2011-01-25

Polymer vesicles made from poly(isoprene-b-styrene-b-2-vinyl pyridine) (PI-b-PS-b-P2VP) triblock copolymer confined within the nanopores of an anodic aluminum oxide (AAO) membrane are studied. It was found that these vesicles have well-defined, nanoscopic size, and complex microphase-separated hydrophobic membranes, comprised of the PS and PI blocks, while the coronas are formed by the P2VP block. Vesicle formation was tracked using both transmission and scanning electron microscopy. A mesh-like morphology formed in the membrane at a well-defined composition of the three blocks that can be tuned by changing the copolymer composition. The nanoscale confinement, copolymer composition, and subtle molecular interactions contribute to the generation of these vesicles with such unusual morphologies.

Fluorene-based narrow-band-gap copolymers for red light- emitting diodes and bulk heterojunction photovoltaic cells

Institute of Scientific and Technical Information of China (English)

Mingliang SUN; Li WANG; Yangjun XIA; Bin DU; Ransheng LIU; Yong CAO

2008-01-01

A series of narrow band-gap conjugated copo-lymers (PFO-DDQ) derived from 9,9-dioctylfluorene (DOF) and 2,3-dimethyl-5,8-dithien-2-yl-quinoxalines (DDQ) is prepaid by the palladium-catalyzed Suzuki coupling reaction with the molar feed ratio of DDQ at around 1%,5%,15%,30% and 50%,respectively.The obtained polymers are readily soluble in common organic solvents.The solutions and the thin solid films of the copolymers absorb light from 300-590 nm with two absorbance.peaks at around 380 and 490 nm.The intens-ity of 490 nm peak increases with the increasing DDQ content in the polymers.Efficient energy transfer due to exciton trapping on narrow-band-gap DDQ sites has been observed.The PL emission consists exclusively of DDQ unit emission at around 591 643 nm depending on the DDQ content in solid film.The EL emission peaks are red-shifted from 580 nm for PFO-DDQ1 to 635 nm for PFO-DDQ50.The highest external quantum efficiency achieved with the device configuration ITO/PEDOT/ PVK/PFO-DDQt5/Ba/A1 is 1.33% with a luminous effi-ciency 1.54 cd/A.Bulk heterojunction photovoltaic cells fabricated from composite films of PFO-DDQ30 copoly-mer and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) as electron donor and electron acceptor,respect-ively in device configuration:ITO/PEDOT:PSS/PFO-DDQ30:PCBM/PFPNBr/Al shows power conversion effi-ciencies of 1.18% with open-circuit voltage (Voc) of 0.90 V and short-circuit current density (Jsc) of 2.66 mA/cm2 under an AM1.5 solar simulator (100 mW/cm2).The photocurrent response wavelengths of the PVCs based on PFO-DDQ30/PCBM blends covers 300-700 nm.This indicates that these kinds of low band-gap polymers are promising candidates for polymeric solar cells and red light-emitting diodes.

Effects of nanoparticles on the compatibility of PEO-PMMA block copolymers.

Science.gov (United States)

Mu, Dan; Li, Jian-Quan; Li, Wei-Dong; Wang, Song

2011-12-01

The compatibility of six kinds of designed poly(ethylene oxide)-block-poly(methyl methacrylate) (PEO-b-PMMA) copolymers was studied at 270, 298 and 400 K via mesoscopic modeling. The values of the order parameters depended on both the structures of the block copolymers and the simulation temperature, while the values of the order parameters of the long chains were higher than those of the short ones; temperature had a more obvious effect on long chains than on the short ones. Plain copolymers doped with poly(ethylene oxide) (PEO) or poly(methyl methacrylate) (PMMA) homopolymer showed different order parameter values. When a triblock copolymer had the same component at both ends and was doped with one of its component polymers as a homopolymer (such as A5B6A5 doped with B6 or A5 homopolymer), the value of its order parameter depended on the simulation temperature. The highest order parameter values were observed for A5B6A5 doped with B6 at 400 K and for A5B6A5 doped with A5 at 270 K. A study of copolymers doped with nanoparticles showed that the mesoscopic phase was influenced by not only the properties of the nanoparticles, such as the size and density, but also the compositions of the copolymers. Increasing the size of the nanoparticles used as a dopant had the most significant effect on the phase morphologies of the copolymers.

Anomalous Behaviors of Block Copolymers at the Interface of an Immiscible Polymer Blend

Science.gov (United States)

Ryu, Ji Ho; Lee, Won Bo

We investigate the effects of structure and stiffness of block copolymers on the interface of an immiscible polymer blend using coarse-grained molecular dynamics (CGMD) simulation. The diblock and grafted copolymers, which are described by Kremer and Grest bead spring model, are used to compare the compatibilization efficiency, that is, reduction of the interfacial tension. It is found that, overall, the grafted copolymers are located more compactly at the interface and show better compatibilization efficiency than diblock copolymers. In addition, it is noted that an increase in the stiffness of one block of diblock copolymer causes inhomogeneous interfacial coverage due to bundle formation among the stiff blocks and orientational constraint on bundled structures near the interface, which makes copolymers poor compatibilizers. The dependence of anomalous orientational constraint on the chain length of homopolymers is also investigated. Theoretical and Computational Soft Matters Lab.

Responsive copolymers for enhanced petroleum recovery. Annual report

Energy Technology Data Exchange (ETDEWEB)

McCormick, C.; Hester, R.

1994-08-01

A coordinated research program involving synthesis, characterization, and rheology has been undertaken to develop advanced polymer system which should be significantly more efficient than polymers presently used for mobility control and conformance. Unlike the relatively inefficient, traditional EOR polymers, these advanced polymer systems possess microstructural features responsive to temperature, electrolyte concentration, and shear conditions. Contents of this report include the following chapters. (1) First annual report responsive copolymers for enhanced oil recovery. (2) Copolymers of acrylamide and sodium 3-acrylamido-3-methylbutanoate. (3) Terpolymers of NaAMB, Am, and n-decylacrylamide. (4) Synthesis and characterization of electrolyte responsive terpolymers of acrylamide, N-(4-butyl)phenylacrylamide, and sodium acrylate, sodium-2-acrylamido-2-methylpropanesulphonate or sodium-3-acrylamido-3-methylbutanoate. (5) Synthesis and solution properties of associative acrylamido copolymers with pyrensulfonamide fluorescence labels. (6) Photophysical studies of the solution behavior of associative pyrenesulfonamide-labeled polyacrylamides. (7) Ampholytic copolymers of sodium 2-(acrylamido)-2-methylpropanesulfonate with [2-(acrylamido)-2-methypropyl]trimethylammonium chloride. (8) Ampholytic terpolymers of acrylamide with sodium 2-acrylamido-2-methylpropanesulphoante and 2-acrylamido-2-methylpropanetrimethyl-ammonium chloride and (9) Polymer solution extensional behavior in porous media.

Preservation of beech and spruce wood by allyl alcohol-based copolymers

International Nuclear Information System (INIS)

Solpan, Dilek; Gueven, Olgun

1999-01-01

Allyl alcohol (AA), acrylonitrile (AN), methyl methacrylate (MMA), monomers and monomer mixtures AA+AN, AA+MMA were used to conserve and consolidate Beech and Spruce. After impregnation, copolymerisation and polymerisation were accomplished by gamma irradiation. The fine structure of wood+polymer(copolymer) composites was investigated by Scanning Electron Microscopy (SEM). It was observed that copolymer obtained from AA+MMA monomer mixture showed the optimum compatibility. The compressional strength and Brinell Hardness Numbers determined for untreated and treated wood samples indicated that the mechanical strength of wood+copolymer composites was increased. It was found that the mechanical strength of the wood samples containing the AA+MMA copolymer was higher than the others. In the presence of P(AA/MMA), at highest conversion, the compressive strength perpendicular to the fibres in Beech and Spruce increased approximately 100 times. The water uptake capacity of wood+copolymer composites was observed to decrease by more than 50% relative to the original samples, and biodegradation did not take place

Thermo-responsive block copolymers

NARCIS (Netherlands)

Mocan Cetintas, Merve

2017-01-01

Block copolymers (BCPs) are remarkable materials because of their self-assembly behavior into nano-sized regular structures and high tunable properties. BCPs are in used various applications such as surfactants, nanolithography, biomedicine and nanoporous membranes. In these thesis, we aimed to

Molecular architecture of electroactive and biodegradable copolymers composed of polylactide and carboxyl-capped aniline trimer.

Science.gov (United States)

Guo, Baolin; Finne-Wistrand, Anna; Albertsson, Ann-Christine

2010-04-12

Two-, four-, and six-armed branched copolymers with electroactive and biodegradable properties were synthesized by coupling reactions between poly(l-lactides) (PLLAs) with different architecture and carboxyl-capped aniline trimer (CCAT). The aniline oligomer CCAT was prepared from amino-capped aniline trimer and succinic anhydride. FT-IR, NMR, and SEC analyses confirmed the structure of the branched copolymers. UV-vis spectra and cyclic voltammetry of CCAT and copolymer solution showed good electroactive properties, similar to those of polyaniline. The water contact angle of the PLLAs was the highest, followed by the undoped copolymer and the doped copolymers. The values of doped four-armed copolymers were 54-63 degrees . Thermal properties of the polymers were studied by DSC and TGA. The copolymers had better thermal stability than the pure PLLAs, and the T(g) between 48-58 degrees C and T(m) between 146-177 degrees C of the copolymers were lower than those of the pure PLLA counterparts. This kind of electroactive and biodegradable copolymer has a great potential for applications in cardiovascular or neuronal tissue engineering.

New thiol-responsive mono-cleavable block copolymer micelles labeled with single disulfides.

Science.gov (United States)

Sourkohi, Behnoush Khorsand; Schmidt, Rolf; Oh, Jung Kwon

2011-10-18

Thiol-responsive symmetric triblock copolymers having single disulfide linkages in the middle blocks (called mono-cleavable block copolymers, ss-ABP(2)) were synthesized by atom transfer radical polymerization in the presence of a disulfide-labeled difunctional Br-initiator. These brush-like triblock copolymers consist of a hydrophobic polyacrylate block having pendent oligo(propylene oxide) and a hydrophilic polymethacrylate block having pendent oligo(ethylene oxide). Gel permeation chromatography and (1)H NMR results confirmed the synthesis of well-defined mono-cleavable block copolymers and revealed that polymerizations were well controlled. Because of amphiphilic nature, these copolymers self-assembled to form colloidally stable micelles above critical micellar concentration of 0.032 mg · mL(-1). In response to reductive reactions, disulfides in thiol-responsive micelles were cleaved. Atomic force microscopy and dynamic light scattering analysis suggested that the cleavage of disulfides caused dissociation of micelles to smaller-sized assembled structures in water. Moreover, in a biomedical perspective, the mono-cleavable block copolymer micelles are not cytotoxic and thus biocompatible. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Time-resolved GISAXS and cryo-microscopy characterization of block copolymer membrane formation

KAUST Repository

Marques, Debora S.; Dorin, Rachel Mika; Wiesner, Ulrich B.; Smilgies, Detlef Matthias; Behzad, Ali Reza; Vainio, Ulla; Peinemann, Klaus-Viktor; Nunes, Suzana Pereira

2014-01-01

Time-resolved grazing-incidence small-angle X-ray scattering (GISAXS) and cryo-microscopy were used for the first time to understand the pore evolution by copolymer assembly, leading to the formation of isoporous membranes with exceptional porosity and regularity. The formation of copolymer micelle strings in solution (in DMF/DOX/THF and DMF/DOX) was confirmed by cryo field emission scanning electron microscopy (cryo-FESEM) with a distance of 72 nm between centers of micelles placed in different strings. SAXS measurement of block copolymer solutions in DMF/DOX indicated hexagonal assembly with micelle-to-micelle distance of 84-87 nm for 14-20 wt% copolymer solutions. GISAXS in-plane peaks were detected, revealing order close to hexagonal. The d-spacing corresponding to the first peak in this case was 100-130 nm (lattice constant 115-150 nm) for 17 wt% copolymer solutions evaporating up to 100 s. Time-resolved cryo-FESEM showed the formation of incipient pores on the film surface after 4 s copolymer solution casting with distances between void centers of 125 nm. © 2014 Elsevier Ltd. All rights reserved.

Time-resolved GISAXS and cryo-microscopy characterization of block copolymer membrane formation

KAUST Repository

Marques, Debora S.

2014-03-01

Time-resolved grazing-incidence small-angle X-ray scattering (GISAXS) and cryo-microscopy were used for the first time to understand the pore evolution by copolymer assembly, leading to the formation of isoporous membranes with exceptional porosity and regularity. The formation of copolymer micelle strings in solution (in DMF/DOX/THF and DMF/DOX) was confirmed by cryo field emission scanning electron microscopy (cryo-FESEM) with a distance of 72 nm between centers of micelles placed in different strings. SAXS measurement of block copolymer solutions in DMF/DOX indicated hexagonal assembly with micelle-to-micelle distance of 84-87 nm for 14-20 wt% copolymer solutions. GISAXS in-plane peaks were detected, revealing order close to hexagonal. The d-spacing corresponding to the first peak in this case was 100-130 nm (lattice constant 115-150 nm) for 17 wt% copolymer solutions evaporating up to 100 s. Time-resolved cryo-FESEM showed the formation of incipient pores on the film surface after 4 s copolymer solution casting with distances between void centers of 125 nm. © 2014 Elsevier Ltd. All rights reserved.

Hydrophilic block copolymer-directed growth of lanthanum hydroxide nano-particles

Energy Technology Data Exchange (ETDEWEB)

Bouyer, F.; Sanson, N.; Gerardin, C. [Laboratoire de Materiaux Catalytiques et Catalyse en Chimie Organique, UMR 5618 CNRS-ENSCM-UM1, FR 1878, Institut Gerhardt, 34 - Montpellier (France); Destarac, M. [Centre de Recherches Rhodia Aubervilliers, 93 - Aubervilliers (France)

2006-03-15

Stable hairy lanthanum hydroxide nano-particles were synthesized in water by performing hydrolysis and condensation reactions of lanthanum cations in the presence of double hydrophilic poly-acrylic acid-b-polyacrylamide block copolymers (PAA-b-PAM). In the first step, the addition of asymmetric PAA-b-PAM copolymers (M{sub w,PAA} {<=} M{sub w,PAM}) to lanthanum salt solutions, both at pH = 5.5, induces the formation of monodispersed micellar aggregates, which are predominantly isotropic. The core of the hybrid aggregates is constituted of a lanthanum polyacrylate complex whose formation is due to bidentate coordination bonding between La{sup 3+} and acrylate groups, as shown by ATR-FTIR experiments and pH measurements. The size of the micellar aggregates depends on the molecular weight of the copolymer but is independent of the copolymer to metal ratio in solution. In the second step, the hydrolysis of lanthanum ions is induced by addition of a strong base such as sodium hydroxide. Either flocculated suspensions or stable anisotropic or spherical nano-particles of lanthanum hydrolysis products were obtained depending on the metal complexation ratio [acrylate]/[La]. The variation of that parameter also enables the control of the size of the core-corona nano-particles obtained by lanthanum hydroxylation. The asymmetry degree of the copolymer was shown to influence both the size and the shape of the particles. Elongated particles with a high aspect ratio, up to 10, were obtained with very asymmetric copolymers (M{sub w,PAM}/M{sub w,PAA}{>=}10) while shorter rice grain-like particles were obtained with a less asymmetric copolymer. The asymmetry degree also influences the value of the critical metal complexation degree required to obtain stable colloidal suspensions of polymer-stabilized lanthanum hydroxide. (authors)

Self-oscillating AB diblock copolymer developed by post modification strategy

Energy Technology Data Exchange (ETDEWEB)

Ueki, Takeshi, E-mail: ueki@cross.t.u-tokyo.ac.jp, E-mail: ryo@cross.t.u-tokyo.ac.jp; Onoda, Michika; Tamate, Ryota; Yoshida, Ryo, E-mail: ueki@cross.t.u-tokyo.ac.jp, E-mail: ryo@cross.t.u-tokyo.ac.jp [Department of Materials Engineering, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Shibayama, Mitsuhiro [Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwano-ha, Kashiwa, Chiba 277-8581 (Japan)

2015-06-15

We prepared AB diblock copolymer composed of hydrophilic poly(ethylene oxide) segment and self-oscillating polymer segment. In the latter segment, ruthenium tris(2,2′-bipyridine) (Ru(bpy){sub 3}), a catalyst of the Belousov-Zhabotinsky reaction, is introduced into the polymer architecture based on N-isopropylacrylamide (NIPAAm). The Ru(bpy){sub 3} was introduced into the polymer segment by two methods; (i) direct random copolymerization (DP) of NIPAAm and Ru(bpy){sub 3} vinyl monomer and (ii) post modification (PM) of Ru(bpy){sub 3} with random copolymer of NIPAAm and N-3-aminopropylmethacrylamide. For both the diblock copolymers, a bistable temperature region (the temperature range; ΔT{sub m}), where the block copolymer self-assembles into micelle at reduced Ru(bpy){sub 3}{sup 2+} state whereas it breaks-up into individual polymer chain at oxidized Ru(bpy){sub 3}{sup 3+} state, monotonically extends as the composition of the Ru(bpy){sub 3} increases. The ΔT{sub m} of the block copolymer prepared by PM is larger than that by DP. The difference in ΔT{sub m} is rationalized from the statistical analysis of the arrangement of the Ru(bpy){sub 3} moiety along the self-oscillating segments. By using the PM method, the well-defined AB diblock copolymer having ΔT{sub m} (ca. 25 °C) large enough to cause stable self-oscillation can be prepared. The periodic structural transition of the diblock copolymer in a dilute solution ([Polymer] = 0.1 wt. %) is closely investigated in terms of the time-resolved dynamic light scattering technique at constant temperature in the bistable region. A macroscopic viscosity oscillation of a concentrated polymer solution (15 wt. %) coupled with the periodic microphase separation is also demonstrated.

Temperature-Responsive Biocompatible Copolymers Incorporating Hyperbranched Polyglycerols for Adjustable Functionality

Directory of Open Access Journals (Sweden)

Alan J. House

2011-08-01

Full Text Available Temperature-triggered copolymers are proposed for a number of bio-applications but there is no ideal material platform, especially for injectable drug delivery. Options are needed for degradable biomaterials that not only respond to temperature but also easily accommodate linkage of active molecules. A first step toward realizing this goal is the design and synthesis of the novel materials reported herein. A multifunctional macromer, methacrylated hyperbranched polyglycerol (HPG-MA with an average of one acrylate unit per copolymer, was synthesized and copolymerized with N-isopropylacrylamide (NIPAAm, hydroxyethyl methacrylate-polylactide (HEMAPLA and acrylic acid (AAc. The potential to fully exploit the copolymers by modification of the multiple HPG hydroxyl groups will not be discussed here. Instead, this report focuses on the thermoresponsive, biocompatible, and degradation properties of the material. Poly(NIPAAm-co-HEMAPLA-co-AAc-co-HPG-MA displayed increasing lower critical solution temperatures (LCST as the HPG content increased over a range of macromer ratios. For the copolymer with the maximum HPG incorporation (17%, the LCST was ~30 °C. In addition, this sample showed no toxicity when human uterine fibroid cells were co-cultured with the copolymer for up to 72 h. This copolymer lost approximately 92% of its mass after 17 hours at 37 °C. Thus, the reported biomaterials offer attractive properties for the design of drug delivery systems where orthogonally triggered mechanisms of therapeutic release in relatively short time periods would be attractive.

Multiblock copolymers synthesized in aqueous dispersions using multifunctional RAFT agents

NARCIS (Netherlands)

Bussels, R.; Bergman-Göttgens, C.M.; Meuldijk, J.; Koning, C.E.

2005-01-01

Triblock copolymers were synthesized in aqueous dispersions in two polymerization steps using a low molar mass difunctional dithiocarbamate-based RAFT agent, and in merely one polymerization step using a macromolecular difunctional dithiocarbamate-based RAFT agent. Segmented block copolymers

Rapid Ordering in "Wet Brush" Block Copolymer/Homopolymer Ternary Blends.

Science.gov (United States)

Doerk, Gregory S; Yager, Kevin G

2017-12-26

The ubiquitous presence of thermodynamically unfavored but kinetically trapped topological defects in nanopatterns formed via self-assembly of block copolymer thin films may prevent their use for many envisioned applications. Here, we demonstrate that lamellae patterns formed by symmetric polystyrene-block-poly(methyl methacrylate) diblock copolymers self-assemble and order extremely rapidly when the diblock copolymers are blended with low molecular weight homopolymers of the constituent blocks. Being in the "wet brush" regime, the homopolymers uniformly distribute within their respective self-assembled microdomains, preventing increases in domain widths. An order-of-magnitude increase in topological grain size in blends over the neat (unblended) diblock copolymer is achieved within minutes of thermal annealing as a result of the significantly higher power law exponent for ordering kinetics in the blends. Moreover, the blends are demonstrated to be capable of rapid and robust domain alignment within micrometer-scale trenches, in contrast to the corresponding neat diblock copolymer. These results can be attributed to the lowering of energy barriers associated with domain boundaries by bringing the system closer to an order-disorder transition through low molecular weight homopolymer blending.

Synthesis and characterization of PEG-conjugated quaternized chitosan and its application as a gene vector.

Science.gov (United States)

Zhang, Xi; Yao, Juan; Zhang, Lihong; Fang, Jianguo; Bian, Fengling

2014-03-15

Poly(ethylene glycol)-conjugated N-(2-hydroxy) propyl-3-trimethyl ammonium chitosan chloride (PHTAC) derivatives were prepared by incorporating PEG molecules onto quaternized chitosan backbone. The copolymers were characterized by FTIR, (1)H NMR and XRD. Agarose gel retardation assay indicated that PHTAC had good plasmid DNA (pDNA) binding capability and the particle sizes of PHTAC/pDNA complexes determined by DLS were about 200 nm. Cytotoxicity assays in HeLa and 293T cells showed that PHTAC had low cytotoxicity. In vitro luciferase assay showed that PHTAC with PEGylation degree of 9% (PHTAC-1) had good transfection efficiency about 5.3-fold higher than quaternized chitosan, which was comparable with PEI (25 kDa). These results suggest that PHTAC-1 is a promising candidate as an efficient nonviral gene vector. Copyright © 2013 Elsevier Ltd. All rights reserved.

Evaluation of iodovinyl antibody conjugates: Comparison with a p-iodobenzoyl conjugate and direct radioiodination

International Nuclear Information System (INIS)

Hadley, S.W.; Wilbur, D.S.

1990-01-01

The preparations and conjugations of 2,3,5,6-tetrafluorophenyl 5-[125I/131I]iodo-4-pentenoate (7a) and 2,3,5,6-tetrafluorophenyl 3,3-dimethyl-5-[125I/131I]iodo-4-pentenoate (7b) to monoclonal antibodies are reported. Reagents 7a and 7b were prepared in high radiochemical yield by iododestannylation of their corresponding 5-tri-n-butylstannyl precursors. Radioiodinated antibody conjugates were prepared by reaction of 7a or 7b with the protein at basic pH. Evaluation of these conjugates by several in vitro procedures demonstrated that the radiolabel was attached to the antibody in a stable manner and that the conjugates maintained immunoreactivity. Comparative dual-isotope biodistribution studies of a monoclonal antibody Fab fragment conjugate of 7a and 7b with the same Fab fragment labeled with N-succinimidyl p-[131I]iodobenzoate (PIB, p-iodobenzoate, 2) or directly radioiodinated have been carried out in tumor-bearing nude mice. Coinjection of the Fab conjugate of 7a with the Fab conjugate of 2 demonstrated that the biodistributions were similar in most organs, except the neck tissue (thyroid-containing) and the stomach, which contained substantially increased levels of the 7a label. Coinjection of the Fab conjugate of 7a with the Fab fragment radioiodinated by using the chloramine-T method demonstrated that the biodistributions were remarkably similar, suggesting roughly equivalent in vivo deiodination of these labeled antibody fragments. Coinjection of the Fab conjugate of 7a with the Fab conjugate of 7b indicated that there was ∼ a 2-fold reduction in the amount of in vivo deiodination of the 7b conjugate as compared to the 7a conjugate

Oxidation effect on templating of metal oxide nanoparticles within block copolymers

International Nuclear Information System (INIS)

Akcora, Pinar; Briber, Robert M.; Kofinas, Peter

2009-01-01

Amphiphilic norbornene-b-(norbornene dicarboxylic acid) diblock copolymers with different block ratios were prepared as templates for the incorporation of iron ions using an ion exchange protocol. The disordered arrangement of iron oxide particles within these copolymers was attributed to the oxidation of the iron ions and the strong interactions between iron oxide nanoparticles, particularly at high iron ion concentrations, which was found to affect the self-assembly of the block copolymer morphologies.

The Preparation and Characterization of Tourmaline-Containing Functional Copolymer p (VST/MMA/BA

Directory of Open Access Journals (Sweden)

Yingmo Hu

2018-01-01

Full Text Available Tourmaline was modified with vinyl triethoxysilane containing double bond to prepare the polymerizable organic vinylsiliconoxyl tourmaline (VST and then copolymerized with methyl methacrylate (MMA and butyl acrylate (BA to produce the tourmaline-containing functional copolymer p (VST/MMA/BA. The structures and morphologies of VST and p (VST/MMA/BA copolymer were characterized by IR, SEM, and EDX. The experimental results indicated that tourmaline was introduced into the copolymer via surface modification and the tourmaline-containing functional copolymer was obtained by a copolymerization process with MMA and BA. The prepared p (VST/MMA/BA copolymer displayed excellent storage stabilities, high far-infrared radiation and negative ion releasing performances, and good mechanical properties.

Distributions of chain ends and junction points in ordered block copolymers

International Nuclear Information System (INIS)

Mayes, A.M.; Johnson, R.D.; Russell, T.P.; Smith, S.D.; Satija, S.K.; Majkrzak, C.F.

1993-01-01

Chain configurations in ordered symmetric poly(styrene-b-methyl methacrylate) diblock copolymers were examined by neutron reflectively. In a thin-film geometry the copolymers organize into lamellar microdomains oriented parallel to the substrate surface. The copolymers organize into lamellar microdomains oriented parallel to the substrate surface. The copolymers were synthesized with small fractions of deuterated segments at either the chain ends or centers. This selective labeling permitted characterization of the spatial distribution of chain ends and junction points normal to the plane of the film. From the reflectivity analysis, the junction points are found to be confined to the PS/PMMA interfacial regions. The chain ends, however, are well distributed through their respective domains, exhibiting only a weak maximum in concentration at the center of the domains

Protein resistance of dextran and dextran-PEG copolymer films

Science.gov (United States)

Kozak, Darby; Chen, Annie; Bax, Jacinda; Trau, Matt

2011-01-01

The protein resistance of dextran and dextran-poly(ethylene glycol) (PEG) copolymer films was examined on an organosilica particle-based assay support. Comb-branched dextran-PEG copolymer films were synthesized in a two step process using the organosilica particle as a solid synthetic support. Particles modified with increasing amounts (0.1-1.2 mg m−2) of three molecular weights (10 000, 66 900, 400 000 g mol−1) of dextran were found to form relatively poor protein-resistant films compared to dextran-PEG copolymers and previously studied PEG films. The efficacy of the antifouling polymer films was found to be dependent on the grafted amount and its composition, with PEG layers being the most efficient, followed by dextran-PEG copolymers, and dextran alone being the least efficient. Immunoglobulin gamma (IgG) adsorption decreased from ~ 5 to 0.5 mg m−2 with increasing amounts of grafted dextran, but bovine serum albumin (BSA) adsorption increased above monolayer coverage (to ~2 mg m−2) indicating ternary adsorption of the smaller protein within the dextran layer. PMID:21614699

STUDIES ON POLY (ETHYLENE TEREPHTHALATE)- POLY ( TETRAMETHYLENE ETHER ) MULTIBLOCK COPOLYMER.Ⅰ. COM POSITIONAL HOMOGENEITY

Institute of Scientific and Technical Information of China (English)

ZHAN Yongjian; YING Qicong; WU Meiyan; QIAN Renyuan

1991-01-01

The compositional homogeneity of a poly (ethylene terephthalate )-poly (tetramethylene ether)multiblock copolymer sample with low content of hard segment was examined by GPC, TLC, and solubility method. The copolymer sample was found to have a uniform composition as a function of elution volume over the major portion of sample from GPC method. However within one elution fraction, the copolymer chains, although having the same hydrodynamic volume, may have some difference in composition. Two fractions with different composition were obtained by precipitation in ethanol. Some low molar mass copolymers were also separated by a TLC technique from the copolymer sample.

Co-conjugation vis-à-vis individual conjugation of α-amylase and glucoamylase for hydrolysis of starch.

Science.gov (United States)

Jadhav, Swati B; Singhal, Rekha S

2013-10-15

Two enzymes, α-amylase and glucoamylase have been individually and co-conjugated to pectin by covalent binding. Both the enzyme systems showed better thermal and pH stability over the free enzyme system with the complete retention of original activities. Mixture of individually conjugated enzymes showed lower inactivation rate constant with longer half life than the co-conjugated enzyme system. Individually conjugated enzymes showed an increase of 56.48 kJ/mole and 38.22 kJ/mole in activation energy for denaturation than the free enzymes and co-conjugated enzymes, respectively. Km as well as Vmax of individually and co-conjugated enzymes was found to be higher than the free enzymes. SDS-polyacrylamide gel electrophoresis confirmed the formation of conjugate and co-conjugate as evident by increased molecular weight. Both the enzyme systems were used for starch hydrolysis where individually conjugated enzymes showed highest release of glucose at 60 °C and pH 5.0 as compared to free and co-conjugated enzyme. Copyright © 2013 Elsevier Ltd. All rights reserved.

Smart PEGylation of trypsin.

Science.gov (United States)

Zarafshani, Zoya; Obata, Toshihiro; Lutz, Jean-François

2010-08-09

Thermoresponsive oligo(ethylene glycol)-based copolymers were investigated for trypsin conjugation. These copolymers have been synthesized by atom transfer radical polymerization of 2-(2-methoxyethoxy)ethyl methacrylate (MEO(2)MA) with oligo(ethylene glycol) methyl ether methacrylate (OEGMA(475), M(n) = 475 g.mol(-1)) at 60 degrees C in the presence of copper(I) chloride and 2,2'-bipyridyl. Two different ATRP initiators, containing succinimidyl ester moieties, were tested, namely, N-succinimidyl-2-bromopropionate and N-succinimidyl-2-bromoisobutyrate. In both cases, ATRP afforded well-defined polymers with a narrow molecular weight distribution and controlled chain-ends. However, the efficiency of initiation of the two initiators was lower than 1 and therefore the formed polymers exhibited a higher than expected mean degree of polymerization. Nevertheless, all types of polymers could be conjugated to trypsin. The conjugation reaction was performed in borax-HCl buffer. Sodium dodecyl sulfate poly(acrylamide) gel electrophoresis (SDS-PAGE) indicated that polymer/enzyme conjugates were obtained in all cases. However, (co)polymers initiated by N-succinimidyl-2-bromopropionate led to the best conjugation results. The formed P(MEO(2)MA-co-OEGMA(475))-trypsin conjugates were found to be thermoresponsive and moreover exhibited a higher enzymatic activity than unmodified trypsin.

Chemical conjugation of cowpea mosaic viruses with reactive HPMA-based polymers

Czech Academy of Sciences Publication Activity Database

Laga, Richard; Koňák, Čestmír; Šubr, Vladimír; Ulbrich, Karel; Suthiwangcharoen, N.; Niu, Q.; Wang, Q.

2010-01-01

Roč. 21, č. 12 (2010), s. 1669-1685 ISSN 0920-5063 R&D Projects: GA AV ČR KJB400500803; GA ČR GA202/09/2078; GA AV ČR KAN200200651 Institutional research plan: CEZ:AV0Z40500505 Keywords : acylthiazolidine-2-thione reactive groups * bioconjugation * coating Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.842, year: 2010

Block copolymer/homopolymer dual-layer hollow fiber membranes

KAUST Repository

Hilke, Roland

2014-12-01

We manufactured the first time block copolymer dual-layer hollow fiber membranes and dual layer flat sheet membranes manufactured by double solution casting and phase inversion in water. The support porous layer was based on polystyrene and the selective layer with isopores was formed by micelle assembly of polystyrene-. b-poly-4-vinyl pyridine. The dual layers had an excellent interfacial adhesion and pore interconnectivity. The dual membranes showed pH response behavior like single layer block copolymer membranes with a low flux for pH values less than 3, a fast increase between pH4 and pH6 and a constant high flux level for pH values above 7. The dry/wet spinning process was optimized to produce dual layer hollow fiber membranes with polystyrene internal support layer and a shell block copolymer selective layer.

Rheological Behavior of Entangled Polystyrene-Polyhedral Oligosilsesquioxane (POSS) Copolymer (Postprint)

National Research Council Canada - National Science Library

Wu, Jian; Mather, Patrick T; Haddad, Timothy S; Kim, Gyeong-Man

2006-01-01

...: random copolymers of polystyrene (PS) and styryl-based polyhedral oligosilsesquioxane (POSS), R7(Si8O12)(C6H4CH=CH2), with R = isobutyl (iBu). A series of styrene-styryl POSS random copolymers with 0, 6, 15, 30, 50 wt...

Study of the mechanical behavior of thermo reversible gels of PS-b-poly(ethylene/butylene)-b-PS triblock copolymers in a selective solvent for the middle block of the copolymer

International Nuclear Information System (INIS)

Hernaez, E.; Inchausti, I.; Quintana, J. R.; Katime, I.

2001-01-01

The thermo reversible gelation of three triblock copolymers polystyrene-b-poly(ethylene/butylene)-b-polystyrene, with different molar mass and a similar chemical composition, in n-octane was studied. The solvent is selective for the middle poly(ethylene/butylene) block of the copolymers. the influence of the molar mass of the three copolymers on the gelation and on the mechanical properties of the gels was analysed. The sol-gel transition temperatures. T g el have been determined and they increase with the copolymer concentration and the copolymer molar mass. On the other land, the mechanical properties of the different gels were examined through oscillatory shear and compressive stress relaxation measurements. The concentration dependence of the elastic storage modules, G' for the three copolymer studied fit a sole straight line in a double-logarithmic scale and its slope (2.22) is close to that expected for systems in good solvents (2.25). As the temperature is near to the sol-gel transition temperate, the elastic modulus are smaller and the relaxation rates are higher. (Author) 12 refs

Ordering phenomena in ABA triblock copolymer gels

DEFF Research Database (Denmark)

Reynders, K.; Mischenko, N.; Kleppinger, R.

1997-01-01

Temperature and concentration dependencies of the degree of order in ABA triblock copolymer gels are discussed. Two factors can influence the ordering phenomena: the conformation of the midblocks (links of the network) and the polydispersity of the endblock domains (nodes of the network). The lat......Temperature and concentration dependencies of the degree of order in ABA triblock copolymer gels are discussed. Two factors can influence the ordering phenomena: the conformation of the midblocks (links of the network) and the polydispersity of the endblock domains (nodes of the network...

The Influence of Conjugated Polymer Side Chain Manipulation on the Efficiency and Stability of Polymer Solar Cells.

Science.gov (United States)

Heckler, Ilona M; Kesters, Jurgen; Defour, Maxime; Madsen, Morten V; Penxten, Huguette; D'Haen, Jan; Van Mele, Bruno; Maes, Wouter; Bundgaard, Eva

2016-03-09

The stability of polymer solar cells (PSCs) can be influenced by the introduction of particular moieties on the conjugated polymer side chains. In this study, two series of donor-acceptor copolymers, based on bis(thienyl)dialkoxybenzene donor and benzo[ c ][1,2,5]thiadiazole (BT) or thiazolo[5,4- d ]thiazole (TzTz) acceptor units, were selected toward effective device scalability by roll-coating. The influence of the partial exchange (5% or 10%) of the solubilizing 2-hexyldecyloxy by alternative 2-phenylethoxy groups on efficiency and stability was investigated. With an increasing 2-phenylethoxy ratio, a decrease in solar cell efficiency was observed for the BT-based series, whereas the efficiencies for the devices based on the TzTz polymers remained approximately the same. The photochemical degradation rate for PSCs based on the TzTz polymers decreased with an increasing 2-phenylethoxy ratio. Lifetime studies under constant sun irradiance showed a diminishing initial degradation rate for the BT-based devices upon including the alternative side chains, whereas the (more stable) TzTz-based devices degraded at a faster rate from the start of the experiment upon partly exchanging the side chains. No clear trends in the degradation behavior, linked to the copolymer structural changes, could be established at this point, evidencing the complex interplay of events determining PSCs' lifetime.

The Influence of Conjugated Polymer Side Chain Manipulation on the Efficiency and Stability of Polymer Solar Cells

Directory of Open Access Journals (Sweden)

Ilona M. Heckler

2016-03-01

Full Text Available The stability of polymer solar cells (PSCs can be influenced by the introduction of particular moieties on the conjugated polymer side chains. In this study, two series of donor-acceptor copolymers, based on bis(thienyldialkoxybenzene donor and benzo[c][1,2,5]thiadiazole (BT or thiazolo[5,4-d]thiazole (TzTz acceptor units, were selected toward effective device scalability by roll-coating. The influence of the partial exchange (5% or 10% of the solubilizing 2-hexyldecyloxy by alternative 2-phenylethoxy groups on efficiency and stability was investigated. With an increasing 2-phenylethoxy ratio, a decrease in solar cell efficiency was observed for the BT-based series, whereas the efficiencies for the devices based on the TzTz polymers remained approximately the same. The photochemical degradation rate for PSCs based on the TzTz polymers decreased with an increasing 2-phenylethoxy ratio. Lifetime studies under constant sun irradiance showed a diminishing initial degradation rate for the BT-based devices upon including the alternative side chains, whereas the (more stable TzTz-based devices degraded at a faster rate from the start of the experiment upon partly exchanging the side chains. No clear trends in the degradation behavior, linked to the copolymer structural changes, could be established at this point, evidencing the complex interplay of events determining PSCs’ lifetime.

Effect of cationic grafted copolymer structure on the encapsulation of bovine serum albumin

International Nuclear Information System (INIS)

Flynn, Nicholas; Topal, Ç. Özge; Hikkaduwa Koralege, Rangika S.; Hartson, Steve; Ranjan, Ashish; Liu, Jing; Pope, Carey; Ramsey, Joshua D.

2016-01-01

The aim of the present study was to evaluate a library of poly-L-lysine (PLL)-graft (g)-polyethylene glycol (PEG) copolymers for the ability to encapsulate effectively a model protein, bovine serum albumin (BSA), and to characterize the stability and protein function of the resulting nanoparticle. A library of nine grafted copolymers was produced by varying PLL molecular weight and PEG grafting ratio. Electrostatic self-assembly of the protein and the grafted copolymer drove encapsulation. The formation of protein/polymer nanoparticles with a core/shell structure was confirmed using PAGE, dynamic light scattering, and electron microscopy. Encapsulation of the BSA into nanoparticles was strongly dependent on the copolymer-to-protein mass ratio, PEG grafting ratio, and PLL molecular weight. A copolymer-to-protein mass ratio of 7:1 and higher was generally required for high levels of encapsulation, and under these conditions, no loss of protein activity was observed. Copolymer characteristics also influenced nanoparticle resistance to polyanions and protease degradation. The results indicate that a copolymer of 15–30 kDa PLL, with a PEG grafting ratio of 10:1, is most promising for protein delivery. - Highlights: • A 4–70 kDa range of PLL-g-PEG copolymers was able to encapsulate BSA into NPs. • Encapsulation of BSA by PLL-g-PEG not only retained but increased esterolytic activity. • NPs were stable against protease degradation and polyanion dissociation.

Effect of cationic grafted copolymer structure on the encapsulation of bovine serum albumin

Energy Technology Data Exchange (ETDEWEB)

Flynn, Nicholas [School of Chemical Engineering, Oklahoma State University, Stillwater, OK 74078 (United States); Topal, Ç. Özge [School of Mechanical and Aerospace Engineering, Oklahoma State University, Stillwater, OK 74078 (United States); Hikkaduwa Koralege, Rangika S. [School of Chemical Engineering, Oklahoma State University, Stillwater, OK 74078 (United States); Hartson, Steve [Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078 (United States); Ranjan, Ashish; Liu, Jing; Pope, Carey [Department of Physiological Sciences, Oklahoma State University, Stillwater, OK 74078 (United States); Ramsey, Joshua D., E-mail: josh.ramsey@okstate.edu [School of Chemical Engineering, Oklahoma State University, Stillwater, OK 74078 (United States)

2016-05-01

The aim of the present study was to evaluate a library of poly-L-lysine (PLL)-graft (g)-polyethylene glycol (PEG) copolymers for the ability to encapsulate effectively a model protein, bovine serum albumin (BSA), and to characterize the stability and protein function of the resulting nanoparticle. A library of nine grafted copolymers was produced by varying PLL molecular weight and PEG grafting ratio. Electrostatic self-assembly of the protein and the grafted copolymer drove encapsulation. The formation of protein/polymer nanoparticles with a core/shell structure was confirmed using PAGE, dynamic light scattering, and electron microscopy. Encapsulation of the BSA into nanoparticles was strongly dependent on the copolymer-to-protein mass ratio, PEG grafting ratio, and PLL molecular weight. A copolymer-to-protein mass ratio of 7:1 and higher was generally required for high levels of encapsulation, and under these conditions, no loss of protein activity was observed. Copolymer characteristics also influenced nanoparticle resistance to polyanions and protease degradation. The results indicate that a copolymer of 15–30 kDa PLL, with a PEG grafting ratio of 10:1, is most promising for protein delivery. - Highlights: • A 4–70 kDa range of PLL-g-PEG copolymers was able to encapsulate BSA into NPs. • Encapsulation of BSA by PLL-g-PEG not only retained but increased esterolytic activity. • NPs were stable against protease degradation and polyanion dissociation.

Ellipsometry measurements of glass transition breadth in bulk films of random, block, and gradient copolymers.

Science.gov (United States)

Mok, M M; Kim, J; Marrou, S R; Torkelson, J M

2010-03-01

Bulk films of random, block and gradient copolymer systems were studied using ellipsometry to demonstrate the applicability of the numerical differentiation technique pioneered by Kawana and Jones for studying the glass transition temperature (T (g)) behavior and thermal expansivities of copolymers possessing different architectures and different levels of nanoheterogeneity. In a series of styrene/n -butyl methacrylate (S/nBMA) random copolymers, T (g) breadths were observed to increase from approximately 17( degrees ) C in styrene-rich cases to almost 30( degrees ) C in nBMA-rich cases, reflecting previous observations of significant nanoheterogeneity in PnBMA homopolymers. The derivative technique also revealed for the first time a substantial increase in glassy-state expansivity with increasing nBMA content in S/nBMA random copolymers, from 1.4x10(-4) K-1 in PS to 3.5x10(-4) K-1 in PnBMA. The first characterization of block copolymer T (g) 's and T (g) breadths by ellipsometry is given, examining the impact of nanophase-segregated copolymer structure on ellipsometric measurements of glass transition. The results show that, while the technique is effective in detecting the two T (g) 's expected in certain block copolymer systems, the details of the glass transition can become suppressed in ellipsometry measurements of a rubbery minor phase under conditions where the matrix is glassy; meanwhile, both transitions are easily discernible by differential scanning calorimetry. Finally, broad glass transition regions were measured in gradient copolymers, yielding in some cases extraordinary T (g) breadths of 69- 71( degrees ) C , factors of 4-5 larger than the T (g) breadths of related homopolymers and random copolymers. Surprisingly, one gradient copolymer demonstrated a slightly narrower T (g) breadth than the S/nBMA random copolymers with the highest nBMA content. This highlights the fact that nanoheterogeneity relevant to the glass transition response in selected

PREPARATION AND PROPERTIES OF MMA/1-PROPYLMETHACRYLATE-POSS COPOLYMER WITH ATOM TRANSFER RADICAL POLYMERIZATION

Institute of Scientific and Technical Information of China (English)

He-xin Zhang; Ho-young Lee; Young-jun Shin; Dong-ho Lee; Seok Kyun Noh

2008-01-01

The methyl methacrylate(MMA)/1-propylmethacrylate-polyhedral oligomeric silsesquioxane(PM-POSS) copolymers were synthesized via atom transfer radical polymerization with CuBr as catalyst.The unreacted PM-POSS monomer could be removed completely by washing the copolymerization product with n-hexane.The copolymers were characterized with 1H-NMR,X-ray diffraction,difierential scanning calorimetry,thermogravimetric analysis and gel permeatlon chromatography.With increasing PM-POSS feed ratio.the total conversion increased while the glass transition temperatures of copolymer decreased.The thermogravimetric analysis demonstrated that the thermal stability of copolymer improved slightly with PM-POSS addition.The molecular weight of copolymers increased with incorporation of PM-POSS.

A semiflexible alternating copolymer chain adsorption on a flat and a fluctuating surface

International Nuclear Information System (INIS)

Mishra, Pramod Kumar

2010-01-01

A lattice model of a directed self-avoiding walk is used to investigate adsorption properties of a semiflexible alternating copolymer chain on an impenetrable flat and fluctuating surface in two (square, hexagonal and rectangular lattice) and three dimensions (cubic lattice). In the cubic lattice case the surface is two-dimensional impenetrable flat and in two dimensions the surface is a fluctuating impenetrable line (hexagonal lattice) and also flat impenetrable line (square and rectangular lattice). Walks of the copolymer chains are directed perpendicular to the plane of the surface and at a suitable value of monomer surface attraction, the copolymer chain gets adsorbed on the surface. To calculate the exact value of the monomer surface attraction, the directed walk model has been solved analytically using the generating function method to discuss results when one type of monomer of the copolymer chain has attractive, repulsive or no interaction with the surface. Results obtained in the flat surface case show that, for a stiffer copolymer chain, adsorption transition occurs at a smaller value of monomer surface attraction than a flexible copolymer chain while in the case of a fluctuating surface, the adsorption transition point is independent of bending energy of the copolymer chain. These features are similar to that of a semiflexible homopolymer chain adsorption.

A semiflexible alternating copolymer chain adsorption on a flat and a fluctuating surface.

Science.gov (United States)

Mishra, Pramod Kumar

2010-04-21

A lattice model of a directed self-avoiding walk is used to investigate adsorption properties of a semiflexible alternating copolymer chain on an impenetrable flat and fluctuating surface in two (square, hexagonal and rectangular lattice) and three dimensions (cubic lattice). In the cubic lattice case the surface is two-dimensional impenetrable flat and in two dimensions the surface is a fluctuating impenetrable line (hexagonal lattice) and also flat impenetrable line (square and rectangular lattice). Walks of the copolymer chains are directed perpendicular to the plane of the surface and at a suitable value of monomer surface attraction, the copolymer chain gets adsorbed on the surface. To calculate the exact value of the monomer surface attraction, the directed walk model has been solved analytically using the generating function method to discuss results when one type of monomer of the copolymer chain has attractive, repulsive or no interaction with the surface. Results obtained in the flat surface case show that, for a stiffer copolymer chain, adsorption transition occurs at a smaller value of monomer surface attraction than a flexible copolymer chain while in the case of a fluctuating surface, the adsorption transition point is independent of bending energy of the copolymer chain. These features are similar to that of a semiflexible homopolymer chain adsorption.

Two-Dimensional Liquid Chromatography Analysis of Polystyrene/Polybutadiene Block Copolymers.

Science.gov (United States)

Lee, Sanghoon; Choi, Heejae; Chang, Taihyun; Staal, Bastiaan

2018-05-15

A detailed characterization of a commercial polystyrene/polybutadiene block copolymer material (Styrolux) was carried out using two-dimensional liquid chromatography (2D-LC). The Styrolux is prepared by statistical linking reaction of two different polystyrene- block-polybutadienyl anion precursors with a multivalent linking agent. Therefore, it is a mixture of a number of branched block copolymers different in molecular weight, composition, and chain architecture. While individual LC analysis, including size exclusion chromatography, interaction chromatography, or liquid chromatography at critical condition, is not good enough to resolve all the polymer species, 2D-LC separations coupling two chromatography methods were able to resolve all polymer species present in the sample; at least 13 block copolymer species and a homopolystyrene blended. Four different 2D-LC analyses combining a different pair of two LC methods provide their characteristic separation results. The separation characteristics of the 2D-LC separations are compared to elucidate the elution characteristics of the block copolymer species.

Synthesis of graft copolymers onto starch and its semiconducting properties

Directory of Open Access Journals (Sweden)

Nevin Çankaya

Full Text Available Literature review has revealed that, although there are studies about grafting on natural polymers, especially on starch, few of them are about electrical properties of graft polymers. Starch methacrylate (St.met was obtained by esterification of OH groups on natural starch polymer for this purpose. Grafting of synthesized N-cyclohexyl acrylamide (NCA and commercial methyl methacrylate (MMA monomers with St.met was done by free radical polymerization method. The graft copolymers were characterized with FT-IR spectra, thermal and elemental analysis. Thermal stabilities of the graft copolymers were determined by TGA (thermo gravimetric analysis method and thermal stability of the copolymers is decreased via grafting. The electrical conductivity of the polymers was measured as a function of temperature and it has been observed that electrical conductivity increases with increasing temperature. The absorbance and transmittance versus wavelength of the polymers have been measured. Keywords: Starch, Graft copolymer, Semiconducting, Thermal stability, Starch methacrylate

Fast assembly of ordered block copolymer nanostructures through microwave annealing.

Science.gov (United States)

Zhang, Xiaojiang; Harris, Kenneth D; Wu, Nathanael L Y; Murphy, Jeffrey N; Buriak, Jillian M

2010-11-23

Block copolymer self-assembly is an innovative technology capable of patterning technologically relevant substrates with nanoscale precision for a range of applications from integrated circuit fabrication to tissue interfacing, for example. In this article, we demonstrate a microwave-based method of rapidly inducing order in block copolymer structures. The technique involves the usage of a commercial microwave reactor to anneal block copolymer films in the presence of appropriate solvents, and we explore the effect of various parameters over the polymer assembly speed and defect density. The approach is applied to the commonly used poly(styrene)-b-poly(methyl methacrylate) (PS-b-PMMA) and poly(styrene)-b-poly(2-vinylpyridine) (PS-b-P2VP) families of block copolymers, and it is found that the substrate resistivity, solvent environment, and anneal temperature all critically influence the self-assembly process. For selected systems, highly ordered patterns were achieved in less than 3 min. In addition, we establish the compatibility of the technique with directed assembly by graphoepitaxy.

Molecular weight and its distribution of tetrafluoroethylene and propylene copolymer

International Nuclear Information System (INIS)

Watanabe, Hiromasa; Okamoto, Jiro; Yamaguchi, Koichi.

1978-04-01

In comparison of molecular structure of tetrafluoroethylene and propylene copolymer produced by radiation and chemical initiators respectively, both were fractionated by elution method and fine structure was examined. For the fractionated sample by radiation, the relation between molecular weight anti Mn and intrinsic viscosity ( eta] is ( eta] = 3.97 x 10 -4 anti Mnsup(0.630) The result is not in agreement with that of the unfractionated sample by radiation, and similar to those of samples by chemical initiators. There is no difference, however, in the elution method of GPC between both these copolymers; the elution behavior agrees with that of standard polystyrene. Long chain branching thus exists little in the copolymer of tetrafluoroethylene and propylene. To reveal the relations between reaction conditions and molecular weight and its distribution of the copolymer produced by flow apparatus, the molecular weight distribution was measured by GPC. The method of analysis could evaluate molecular weight distribution changing constantly. (auth.)

Polystyrene-b-polyethylene oxide block copolymer membranes, methods of making, and methods of use

KAUST Repository

Peinemann, Klaus-Viktor; Karunakaran, Madhavan

2015-01-01

Embodiments of the present disclosure provide for polystyrene-b-polyethylene oxide (PS-b-PEO) block copolymer nanoporous membranes, methods of making a PS-b-PEO block copolymer nanoporous membrane, methods of using PS-b-PEO block copolymer nanoporous membranes, and the like.

Polystyrene-b-polyethylene oxide block copolymer membranes, methods of making, and methods of use

KAUST Repository

Peinemann, Klaus-Viktor

2015-04-16

Embodiments of the present disclosure provide for polystyrene-b-polyethylene oxide (PS-b-PEO) block copolymer nanoporous membranes, methods of making a PS-b-PEO block copolymer nanoporous membrane, methods of using PS-b-PEO block copolymer nanoporous membranes, and the like.

Facile synthesis and characterization of novel biodegradable amphiphilic block copolymers bearing pendant hydroxyl groups

Energy Technology Data Exchange (ETDEWEB)

Hu, Gaicen; Fan, Xiaoshan; Xu, Bingcan; Zhang, Delong; Hu, Zhiguo, E-mail: zghu@htu.cn

2014-10-01

Novel amphiphilic block copolymers bearing pendant hydroxyl groups polylactide-b–poly(3,3-bis(Hydroxymethyl–triazolylmethyl) oxetane)-b–polylactide (PLA-b–PHMTYO-b–PLA) were synthesized via a facile and efficient method. First, the block copolymer intermediates polylactide-b–poly(3,3-Diazidomethyloxetane)-b–polylactide (PLA-b–PBAMO-b–PLA) were synthesized through ring-opening polymerization of lactide using PBAMO as a macroinitiator. Following “Click” reaction of PLA-b–PBAMO-b–PLA with propargyl alcohol provided the targeted amphiphilic block copolymers PLA-b–PHMTYO-b–PLA with pendant hydroxyl groups. The composition and structure of prepared copolymers were characterized by {sup 1}H nuclear magnetic resonance ({sup 1}H NMR) spectroscopy, Fourier transform infrared (FT-IR) and gel permeation chromatography (GPC). The self-assembly behavior of the copolymers in water was investigated by transmission electron microscope (TEM), dynamic light scattering (DLS) and static light scattering (SLS). The results showed that the novel copolymers PLA-b–PHMTYO-b–PLA self-assembled into spherical micelles with diameters ranging from 100 nm to 200 nm in aqueous solution. These copolymers also exhibited low critical micellar concentrations (CMC: 6.9 × 10{sup −4} mg/mL and 3.9 × 10{sup −5} mg/mL, respectively). In addition, the in vitro cytotoxicity of these copolymers was determined in the presence of L929 cells. The results showed that the block copolymers PLA-b–PHMTYO-b–PLA exhibited better biocompatibility. Therefore, these well-defined copolymers are expected to find some applications in drug delivery or tissue engineering. - Highlights: • The method to synthesize PLA-b–PHMTYO-b–PLA is relatively facile and efficient. • PLA-b–PHMTYO-b–PLA self-assembles into spherical micelles with low CMC in water. • PLA-b–PHMTYO-b–PLA exhibits better biocompatibility and biodegradability.

Facile synthesis and characterization of novel biodegradable amphiphilic block copolymers bearing pendant hydroxyl groups

International Nuclear Information System (INIS)

Hu, Gaicen; Fan, Xiaoshan; Xu, Bingcan; Zhang, Delong; Hu, Zhiguo

2014-01-01

Novel amphiphilic block copolymers bearing pendant hydroxyl groups polylactide-b–poly(3,3-bis(Hydroxymethyl–triazolylmethyl) oxetane)-b–polylactide (PLA-b–PHMTYO-b–PLA) were synthesized via a facile and efficient method. First, the block copolymer intermediates polylactide-b–poly(3,3-Diazidomethyloxetane)-b–polylactide (PLA-b–PBAMO-b–PLA) were synthesized through ring-opening polymerization of lactide using PBAMO as a macroinitiator. Following “Click” reaction of PLA-b–PBAMO-b–PLA with propargyl alcohol provided the targeted amphiphilic block copolymers PLA-b–PHMTYO-b–PLA with pendant hydroxyl groups. The composition and structure of prepared copolymers were characterized by 1 H nuclear magnetic resonance ( 1 H NMR) spectroscopy, Fourier transform infrared (FT-IR) and gel permeation chromatography (GPC). The self-assembly behavior of the copolymers in water was investigated by transmission electron microscope (TEM), dynamic light scattering (DLS) and static light scattering (SLS). The results showed that the novel copolymers PLA-b–PHMTYO-b–PLA self-assembled into spherical micelles with diameters ranging from 100 nm to 200 nm in aqueous solution. These copolymers also exhibited low critical micellar concentrations (CMC: 6.9 × 10 −4 mg/mL and 3.9 × 10 −5 mg/mL, respectively). In addition, the in vitro cytotoxicity of these copolymers was determined in the presence of L929 cells. The results showed that the block copolymers PLA-b–PHMTYO-b–PLA exhibited better biocompatibility. Therefore, these well-defined copolymers are expected to find some applications in drug delivery or tissue engineering. - Highlights: • The method to synthesize PLA-b–PHMTYO-b–PLA is relatively facile and efficient. • PLA-b–PHMTYO-b–PLA self-assembles into spherical micelles with low CMC in water. • PLA-b–PHMTYO-b–PLA exhibits better biocompatibility and biodegradability

Synthesis of biodegradable and electroactive multiblock polylactide and aniline pentamer copolymer for tissue engineering applications.

Science.gov (United States)

Huang, Lihong; Zhuang, Xiuli; Hu, Jun; Lang, Le; Zhang, Peibiao; Wang, Yu; Chen, Xuesi; Wei, Yen; Jing, Xiabin

2008-03-01

To obtain one biodegradable and electroactive polymer as the scaffold for tissue engineering, the multiblock copolymer PLAAP was designed and synthesized with the condensation polymerization of hydroxyl-capped poly( l-lactide) (PLA) and carboxyl-capped aniline pentamer (AP). The PLAAP copolymer exhibited excellent electroactivity, solubility, and biodegradability. At the same time, as one scaffold material, PLAAP copolymer possesses certain mechanical properties with the tensile strength of 3 MPa, tensile Young 's modulus of 32 MPa, and breaking elongation rate of 95%. We systematically studied the compatibility of PLAAP copolymer in vitro and proved that the electroactive PLAAP copolymer was innocuous, biocompatible, and helpful for the adhesion and proliferation of rat C6 cells. Moreover, the PLAAP copolymer stimulated by electrical signals was demonstrated as accelerating the differentiation of rat neuronal pheochromocytoma PC-12 cells. This biodegradable and electroactive PLAAP copolymer thus possessed the properties in favor of the long-time application in vivo as nerve repair scaffold materials in tissue engineering.

High-Tg Polynorbornene-Based Block and Random Copolymers for Butanol Pervaporation Membranes

Science.gov (United States)

Register, Richard A.; Kim, Dong-Gyun; Takigawa, Tamami; Kashino, Tomomasa; Burtovyy, Oleksandr; Bell, Andrew

Vinyl addition polymers of substituted norbornene (NB) monomers possess desirably high glass transition temperatures (Tg); however, until very recently, the lack of an applicable living polymerization chemistry has precluded the synthesis of such polymers with controlled architecture, or copolymers with controlled sequence distribution. We have recently synthesized block and random copolymers of NB monomers bearing hydroxyhexafluoroisopropyl and n-butyl substituents (HFANB and BuNB) via living vinyl addition polymerization with Pd-based catalysts. Both series of polymers were cast into the selective skin layers of thin film composite (TFC) membranes, and these organophilic membranes investigated for the isolation of n-butanol from dilute aqueous solution (model fermentation broth) via pervaporation. The block copolymers show well-defined microphase-separated morphologies, both in bulk and as the selective skin layers on TFC membranes, while the random copolymers are homogeneous. Both block and random vinyl addition copolymers are effective as n-butanol pervaporation membranes, with the block copolymers showing a better flux-selectivity balance. While polyHFANB has much higher permeability and n-butanol selectivity than polyBuNB, incorporating BuNB units into the polymer (in either a block or random sequence) limits the swelling of the polyHFANB and thereby improves the n-butanol pervaporation selectivity.

Novel Pentablock Copolymers as Thermosensitive Self-Assembling Micelles for Ocular Drug Delivery

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Mitra Alami-Milani

2017-04-01

Full Text Available Many studies have focused on how drugs are formulated in the sol state at room temperature leading to the formation of in situ gel at eye temperature to provide a controlled drug release. Stimuli-responsive block copolymer hydrogels possess several advantages including uncomplicated drug formulation and ease of application, no organic solvent, protective environment for drugs, site-specificity, prolonged and localized drug delivery, lower systemic toxicity, and capability to deliver both hydrophobic and hydrophilic drugs. Self-assembling block copolymers (such as diblock, triblock, and pentablock copolymers with large solubility variation between hydrophilic and hydrophobic segments are capable of making temperature-dependent micellar assembles, and with further increase in the temperature, of jellifying due to micellar aggregation. In general, molecular weight, hydrophobicity, and block arrangement have a significant effect on polymer crystallinity, micelle size, and in vitro drug release profile. The limitations of creature triblock copolymers as initial burst release can be largely avoided using micelles made of pentablock copolymers. Moreover, formulations based on pentablock copolymers can sustain drug release for a longer time. The present study aims to provide a concise overview of the initial and recent progresses in the design of hydrogel-based ocular drug delivery systems.

Hydrophilization of poly(caprolactone copolymers through introduction of oligo(ethylene glycol moieties.

Directory of Open Access Journals (Sweden)

Jonathan J Wurth

Full Text Available In this study, a new family of poly(ε-caprolactone (PCL copolymers that bear oligo(ethylene glycol (OEG moieties is described. The synthesis of three different oligo(ethylene glycol functionalized epoxide monomers derived from 2-methyl-4-pentenoic acid, and their copolymerization with ε-caprolactone (CL to poly(CL-co-OEG-MPO copolymers is presented. The statistical copolymerization initiated with SnOct2/BnOH yielded the copolymers with varying OEG content and composition. The linear relationship between feed ratio and incorporation of the OEG co-monomer enables control over backbone functional group density. The introduction of OEG moieties influenced both the thermal and the hydrophilic characteristics of the copolymers. Both increasing OEG length and backbone content resulted in a decrease in static water contact angle. The introduction of OEG side chains in the PCL copolymers had no adverse influence on MC-3TE3-E1 cell interaction. However, changes to cell form factor (Φ were observed. While unmodified PCL promoted elongated (anisotropic morphologies (Φ = 0.094, PCL copolymer with tri-ethylene glycol side chains at or above seven percent backbone incorporation induced more isotropic cell morphologies (Φ = 0.184 similar to those observed on glass controls (Φ = 0.151.

21 CFR 177.1030 - Acrylonitrile/butadiene/styrene/methyl methacrylate copolymer.

Science.gov (United States)

2010-04-01

... methacrylate copolymer identified in this section may be safely used as an article or component of articles... monomer content of the finished copolymer articles is not more than 11 parts per million as determined by... available from the Center for Food Safety and Applied Nutrition (HFS-200), Food and Drug Administration...

Investigation of some copolymers based on acrylic salts as circulation loss control agents

Directory of Open Access Journals (Sweden)

Ahmed Mohamed Alsabagh

2013-12-01

The prepared copolymers were investigated as loss circulation control materials by measuring different filtration parameters such as; spurt loss, fluid loss and permeability plugging tester value according to the American Petroleum Institute (API standard. From the obtained data, it was found that the 0.6% from the poly[PA-co-AM](0.4:0.6 exhibited the best results of the filtration parameters among the other copolymers. At the same time all the studied copolymers enhanced the rheological properties of the drilling mud. These results were discussed on the light of the swelling capacity of the copolymers.

Poly(l-lysine)-graft-folic acid-coupled poly(2-methyl-2-oxazoline) (PLL-g-PMOXA-c-FA): a bioactive copolymer for specific targeting to folate receptor-positive cancer cells.

Science.gov (United States)

Chen, Yin; Cao, Wenbin; Zhou, Junli; Pidhatika, Bidhari; Xiong, Bin; Huang, Lu; Tian, Qian; Shu, Yiwei; Wen, Weijia; Hsing, I-Ming; Wu, Hongkai

2015-02-04

In this study, we present the preparation, characterization and application of a novel bioactive copolymer poly(l-lysine)-graft-folic acid-coupled poly(2-methyl-2-oxazoline) (PLL-g-PMOXA-c-FA), which has a specific interaction with folate receptor (FR)-positive cancer cells. Glass surface immobilized with PLL-g-PMOXA-c-FA was demonstrated to be adhesive to FR-positive cancer cells (HeLa, JEG-3) while nonadhesive to FR-negative ones (MCF-7, HepG2) in 3 h. The specific interaction between conjugated FA on the substrate and FRs on the cells could hardly be inhibited unless a high concentration (5 mM) of free FA was used due to the multivalent nature of it. The FA functionality ratio of the copolymer on the substrate had a significant influence on the adhesion of HeLa cells, and our experiments revealed that the affinity of the substrate to the cells declined dramatically with the decrease of functionality ratio. This was believed to be caused by the polydispersity of PMOXA tethers, as supported by GPC and ToF-SIMS data. As a proof of concept in the application of our material, we demonstrated successful recovery of HeLa cells from mixture with MCF-7 (1:100) on the copolymer-coated glass, and our results showed that both high sensitivity (95.6 ± 13.3%) and specificity (24.3 ± 8.6%) were achieved.

Synthesis, characterization and antimicrobial activity of important heterocyclic acrylic copolymers

Directory of Open Access Journals (Sweden)

2008-10-01

Full Text Available The acrylate monomer, 7-acryloyloxy-4-methyl coumarin (AMC has been synthesized by reacting 7-hydroxy-4-methyl coumarin, with acryloyl chloride in the presence of NaOH at 0–5°C. Copolymers of 7-acryloyloxy-4-methyl coumarin (AMC with vinyl acetate (VAc were synthesized in DMF (dimethyl formamide solution at 70±1°C using 2,2′-azobisisobutyronitrile (AIBN as an initiator with different monomer-to-monomer ratios in the feed. The copolymers were characterized by Fourier transform infra red (FTIR spectroscopy. The copolymer composition was evaluated by 1H-NMR (proton nuclear magnetic resonance and was further used to determine reactivity ratios. The monomer reactivity ratios for AMC (M1-VAc (M2 pair were determined by the application of conventional linearization methods such as Fineman-Ross (r1 = 0.6924; r2 = 0.6431, Kelen-Tüdõs (r1 = 0.6776; r2 = 0.6374 and extended Kelen-Tüdõs (r1 = 0.6657; r2 = 0.6256. Thermo gravimetric analysis showed that thermal decomposition of the copolymers occurred in single stage in the temperature range of 263–458°C. The molecular weights of the polymers were determined using gel permeation chromatography. The homo and copolymers were tested for their antimicrobial properties against selected microorganisms.

Highly fluorinated comb-shaped copolymer as proton exchange membranes (PEMs): Fuel cell performance

Energy Technology Data Exchange (ETDEWEB)

Kim, Dae Sik; Guiver, Michael D.; Ding, Jianfu [Institute for Chemical Process and Environmental Technology, National Research Council, 1200 Montreal Road, Ottawa, Ontario K1A 0R6 (Canada); Kim, Yu.Seung; Pivovar, Bryan S. [Materials Physics and Applications, Sensors and Electrochemical Devices Group, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

2008-07-15

The fuel cell performance (DMFC and H{sub 2}/air) of highly fluorinated comb-shaped copolymer is reported. The initial performance of membrane electrode assemblies (MEAs) fabricated from comb-shaped copolymer containing a side-chain weight fraction of 22% are compared with those derived from Nafion and sulfonated polysulfone (BPSH-35) under DMFC conditions. The low water uptake of comb copolymer enabled an increase in proton exchange site concentrations in the hydrated polymer, which is a desirable membrane property for DMFC application. The comb-shaped copolymer architecture induces phase separated morphology between the hydrophobic fluoroaromatic backbone and the polysulfonic acid side chains. The initial performance of the MEAs using BPSH-35 and Comb 22 copolymer were comparable and higher than that of the Nafion MEA at all methanol concentrations. For example, the power density of the MEA using Comb 22 copolymer at 350 mA cm{sup -2} and 0.5 M methanol was 145 mW cm{sup -2}, whereas the power densities of MEAs using BPSH-35 were 136 mW cm{sup -2}. The power density of the MEA using Comb 22 copolymer at 350 mA cm{sup -2} and 2.0 M methanol was 144.5 mW cm{sup -2}, whereas the power densities of MEAs using BPSH-35 were 143 mW cm{sup -2}. (author)

Redox-Stability of Alkoxy-BDT Copolymers and their Use for Organic Bioelectronic Devices

KAUST Repository

Giovannitti, Alexander

2018-02-23

Organic semiconductors can be employed as the active layer in accumulation mode organic electrochemical transistors (OECTs), where redox stability in aqueous electrolytes is important for long-term recordings of biological events. It is observed that alkoxy-benzo[1,2-b:4,5-b′]dithiophene (BDT) copolymers can be extremely unstable when they are oxidized in aqueous solutions. The redox stability of these copolymers can be improved by molecular design of the copolymer where it is observed that the electron rich comonomer 3,3′-dimethoxy-2,2′-bithiophene (MeOT2) lowers the oxidation potential and also stabilizes positive charges through delocalization and resonance effects. For copolymers where the comonomers do not have the same ability to stabilize positive charges, irreversible redox reactions are observed with the formation of quinone structures, being detrimental to performance of the materials in OECTs. Charge distribution along the copolymer from density functional theory calculations is seen to be an important factor in the stability of the charged copolymer. As a result of the stabilizing effect of the comonomer, a highly stable OECT performance is observed with transconductances in the mS range. The analysis of the decomposition pathway also raises questions about the general stability of the alkoxy-BDT unit, which is heavily used in donor-acceptor copolymers in the field of photovoltaics.

Redox-Stability of Alkoxy-BDT Copolymers and their Use for Organic Bioelectronic Devices

KAUST Repository

Giovannitti, Alexander; Thorley, Karl J.; Nielsen, Christian B.; Li, Jun; Donahue, Mary J.; Malliaras, George G.; Rivnay, Jonathan; McCulloch, Iain

2018-01-01

Organic semiconductors can be employed as the active layer in accumulation mode organic electrochemical transistors (OECTs), where redox stability in aqueous electrolytes is important for long-term recordings of biological events. It is observed that alkoxy-benzo[1,2-b:4,5-b′]dithiophene (BDT) copolymers can be extremely unstable when they are oxidized in aqueous solutions. The redox stability of these copolymers can be improved by molecular design of the copolymer where it is observed that the electron rich comonomer 3,3′-dimethoxy-2,2′-bithiophene (MeOT2) lowers the oxidation potential and also stabilizes positive charges through delocalization and resonance effects. For copolymers where the comonomers do not have the same ability to stabilize positive charges, irreversible redox reactions are observed with the formation of quinone structures, being detrimental to performance of the materials in OECTs. Charge distribution along the copolymer from density functional theory calculations is seen to be an important factor in the stability of the charged copolymer. As a result of the stabilizing effect of the comonomer, a highly stable OECT performance is observed with transconductances in the mS range. The analysis of the decomposition pathway also raises questions about the general stability of the alkoxy-BDT unit, which is heavily used in donor-acceptor copolymers in the field of photovoltaics.

Formation of nanophases in epoxy thermosets containing amphiphilic block copolymers with linear and star-like topologies.

Science.gov (United States)

Wang, Lei; Zhang, Chongyin; Cong, Houluo; Li, Lei; Zheng, Sixun; Li, Xiuhong; Wang, Jie

2013-07-11

In this work, we investigated the effect of topological structures of block copolymers on the formation of the nanophase in epoxy thermosets containing amphiphilic block copolymers. Two block copolymers composed of poly(ε-caprolactone) (PCL) and poly(2,2,2-trifluoroethyl acrylate) (PTFEA) blocks were synthesized to possess linear and star-shaped topologies. The star-shaped block copolymer composed a polyhedral oligomeric silsesquioxane (POSS) core and eight poly(ε-caprolactone)-block-poly(2,2,2-trifluoroethyl acrylate) (PCL-b-PTFEA) diblock copolymer arms. Both block copolymers were synthesized via the combination of ring-opening polymerization and reversible addition-fragmentation chain transfer/macromolecular design via the interchange of xanthate (RAFT/MADIX) process; they were controlled to have identical compositions of copolymerization and lengths of blocks. Upon incorporating both block copolymers into epoxy thermosets, the spherical PTFEA nanophases were formed in all the cases. However, the sizes of PTFEA nanophases from the star-like block copolymer were significantly lower than those from the linear diblock copolymer. The difference in the nanostructures gave rise to the different glass transition behavior of the nanostructured thermosets. The dependence of PTFEA nanophases on the topologies of block copolymers is interpreted in terms of the conformation of the miscible subchain (viz. PCL) at the surface of PTFEA microdomains and the restriction of POSS cages on the demixing of the thermoset-philic block (viz. PCL).

Ionic Liquids As Self-Assembly Guide for the Formation of Nanostructured Block Copolymer Membranes

KAUST Repository

Madhavan, Poornima

2015-04-30

Nanostructured block copolymer membranes were manufactured by water induced phase inversion, using ionic liquids (ILs) as cosolvents. The effect of ionic liquids on the morphology was investigated, by using polystyrene-b-poly(4-vinyl pyridine) (PS-b-PV4P) diblock as membrane copolymer matrix and imidazolium and pyridinium based ILs. The effect of IL concentration and chemical composition was evident with particular interaction with P4VP blocks. The order of block copolymer/ILs solutions previous to the membrane casting was confirmed by cryo scanning electron microscopy and the morphologies of the manufactured nanostructured membranes were characterized by transmission and scanning electron microscopy. Non-protic ionic liquids facilitate the formation of hexagonal nanoporous block copolymer structure, while protic ILs led to a lamella-structured membrane. The rheology of the IL/block copolymer solutions was investigated, evaluating the storage and loss moduli. Most membranes prepared with ionic liquid had higher water flux than pure block copolymer membranes without additives.

Nanoporous Crosslinked Polyisoprene from Polyisoprene-Polydimethylsiloxane Block Copolymer

DEFF Research Database (Denmark)

Hansen, Michael Steffen; Vigild, Martin Etchells; Berg, Rolf Henrik

2004-01-01

The polyisoprene block of a polyisoprene-polydimethylsiloxane (PI-PDMS) diblock copolymer with 0.68 volume fraction of PI was tightly crosslinked with dicumylperoxide. The PDMS part of the obtained glassy material was subsequently quantitatively etched with anhydrous hydrogen fluoride or tetrabut......The polyisoprene block of a polyisoprene-polydimethylsiloxane (PI-PDMS) diblock copolymer with 0.68 volume fraction of PI was tightly crosslinked with dicumylperoxide. The PDMS part of the obtained glassy material was subsequently quantitatively etched with anhydrous hydrogen fluoride...

Morphology evolution of PS-b-PDMS block copolymer and its hierarchical directed self-assembly on block copolymer templates

DEFF Research Database (Denmark)

Rasappa, Sozaraj; Schulte, Lars; Borah, Dipu

2018-01-01

Cylinder-forming polystyrene-block-polydimethylsiloxane (PS-b-PDMS, 27.2k-b-11.7k, SD39) block copolymer having a total molecular weight of 39 kg mol−1 was exploited to achieve in-plane morphologies of lines, dots and antidots. Brush-free self-assembly of the SD39 on silicon substrates was invest...... substrates provides a simplified method for surface nanopatterning, templated growth of nanomaterials and nanofabrication....... the pattern into the underlying substrate. Directed self-assembly and hierarchical directed self-assembly on block copolymer templates for confinement of dots was successfully demonstrated. The strategy for achieving multiple morphologies using one BCP by mere choice of the annealing solvents on unmodified...

Overview on the Preparation and Characterization of some Itaconic Acid Chelating Copolymers

International Nuclear Information System (INIS)

Abd El-Ghaffar, M.A.; Youssef, E.A.; El-Halawany, N.R.

2005-01-01

Itaconic acid (IA) was copolymerised by an emulsion process with butyl acrylate (BuA), butyl methacrylate (BuMA) and styrene (St) using potassium persulphate/sodium meta bisulphite as a redox initiation system and sodium dodecyl benzene sulfonate as an emulsifier. The rate of copolymerization was found to decrease with increasing (IA) content . The prepared copolymers were characterized by spectrophotometric analysis (IR and lINMR), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) . The monomer reactivity ratios (r1and r2) for the prepared copolymers were determined and discussed . The copolymers having the best properties were incorporated in latex paint formulations. The Ac.. conductivity of the binary itaconic copolymers have been investigated and studied at room temperature and showed semiconducting properties

Tuning of Block Copolymer Membrane Morphology through Water Induced Phase Inversion Technique

KAUST Repository

Madhavan, Poornima

2016-06-01

Isoporous membranes are attractive for the regulation and detection of transport at the molecular level. A well-defined asymmetric membranes from diblock copolymers with an ordered nanoporous membrane morphologies were fabricated by the combination of block copolymer self-assembly and non-solvent-induced phase separation (NIPS) technique. This is a straightforward and fast one step procedure to develop integrally anisotropic (“asymmetric”) membranes having isoporous top selective layer. Membranes prepared via this method exhibit an anisotropic cross section with a thin separation layer supported from underneath a macroporous support. These membrane poses cylindrical pore structure with ordered nanopores across the entire membrane surfaces with pore size in the range from 20 to 40 nm. Tuning the pore morphology of the block copolymer membranes before and after fabrication are of great interest. In this thesis, we first investigated the pore morphology tuning of asymmetric block copolymer membrane by complexing with small organic molecules. We found that the occurrence of hydrogen-bond formation between PS-b-P4VP block copolymer and –OH/ –COOH functionalized organic molecules significantly tunes the pore morphology of asymmetric nanoporous membranes. In addition, we studied the complexation behavior of ionic liquids with PS-b-P4VP block copolymer in solutions and investigated their effect on final membrane morphology during the non-solvent induced phase separation process. We found that non-protic ionic liquids facilitate the formation of hexagonal nanoporous block copolymer structure, while protic ionic liquids led to a lamella-structured membrane. Secondly, we demonstrated the catalytic activity of the gold nanoparticle-enhanced hollow fiber membranes by the reduction of nitrophenol. Also, we systematically investigated the pore morphology of isoporous PS-b-P4VP using 3D imaging technique. Thirdly, we developed well-distributed silver nanoparticles on the

Synthesis and Biological Evaluation of a New Polymeric Conjugate and Nanocarrier with Osteotropic Properties

Directory of Open Access Journals (Sweden)

Rosario Pignatello

2012-01-01

Full Text Available Bone-seeking (osteotropic drug delivery systems (ODDS represent an interesting solution for targeting different types of drugs to the bones. In particular, anticancer and antibacterial agents could take advantage of such therapeutic strategy. We have recently developed an innovative approach to this aim: a new osteotropic biomaterial was prepared, based on the conjugation of a poly(lactide-co-glycolide (PLGA with the bisphosphonate drug alendronate (PLGA-ALE; its hemo- and cytocompatibility were verified. Starting with this copolymer, an osteotropic nanoparticle system (NP was produced for the targeted delivery of antineoplastic drugs to osteolytic bone metastases; in particular, doxorubicin was tested as a model drug. The in vitro and in vivo results of the new ODDS are validated in this article. All the experimental data confirmed that the drug retained its activity after loading in the PLGA-ALE NP; they can be thus considered a new promising strategy for active targeting of drugs to bone tissues in different pathological situations.

Application of Bottlebrush Block Copolymers as Photonic Crystals.

Science.gov (United States)

Liberman-Martin, Allegra L; Chu, Crystal K; Grubbs, Robert H

2017-07-01

Brush block copolymers are a class of comb polymers that feature polymeric side chains densely grafted to a linear backbone. These polymers display interesting properties due to their dense functionality, low entanglement, and ability to rapidly self-assemble to highly ordered nanostructures. The ability to prepare brush polymers with precise structures has been enabled by advancements in controlled polymerization techniques. This Feature Article highlights the development of brush block copolymers as photonic crystals that can reflect visible to near-infrared wavelengths of light. Fabrication of these materials relies on polymer self-assembly processes to achieve nanoscale ordering, which allows for the rapid preparation of photonic crystals from common organic chemical feedstocks. The characteristic physical properties of brush block copolymers are discussed, along with methods for their preparation. Strategies to induce self-assembly at ambient temperatures and the use of blending techniques to tune photonic properties are emphasized. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Adsorption of Poly(ethylene oxide)-Poly(lactide) Copolymers. Effects of Composition and Degradation.

Science.gov (United States)

Muller, Dries; Carlsson, Fredrik; Malmsten, Martin

2001-04-01

The effect of chemical degradation of two diblock copolymers of poly(ethylene oxide) (E) and poly(lactide) (L), E(39)L(5) and E(39)L(20), on their adsorption at silica and methylated silica was investigated with in situ ellipsometry. Steric stablization of polystyrene dispersions was investigated in relation to degradation. Hydrolysis of the poly(lactide) block of the copolymers was followed at different temperatures and pH by using HPLC to measure the occurrence of lactic acid in solution. The block copolymers were quite stable in pH-unadjusted solution at low temperature, whereas degradation was facilitated by increasing temperature or lowering of the pH. Lower degradation rates of E(39)L(20) where observed at low temperature in comparison with those of E(39)L(5), whereas the degradation rates of the copolymers were quantitatively similar at high temperature. The adsorption of the copolymers at methylated silica substrates decreased with increasing degree of degradation due to the reduction in the ability of hydrophobic block to anchor the copolymer layer at the surface. At silica the adsorption initially increased with increasing degradation, particularly for E(39)L(20) due to deposition of aggregates onto the surface. After extensive degradation the adsorption of the copolymers at both silica and methylated silica resembled that of the corresponding poly(ethylene oxide) homopolymer. Overall, it was found that the eventual reduction in adsorption occurred at a lower degree of degradation for E(39)L(5) than for E(39)L(20). Mean-field calculations showed a reduced anchoring for the block copolymers with decreasing poly(lactide) block length at hydrophobic surfaces. In accordance with this finding, it was observed that polystyrene dispersions were stabilized by E(39)L(20) or E(39)L(5) in a way that depended on both the lactide block length and the degree of degradation. Upon degradation of the hydrophobic block, stabilization of the polystyrene dispersions was

21 CFR 177.1315 - Ethylene-1, 4-cyclohexylene dimethylene terephthalate copolymers.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethylene-1, 4-cyclohexylene dimethylene... Ethylene-1, 4-cyclohexylene dimethylene terephthalate copolymers. Ethylene-1, 4-cyclohexylene dimethylene... purposes of this section, ethylene-1,4-cyclohexylene dimethylene terephthalate copolymers (1,4-benzene...

Novel fluorinated block copolymer architectures fuelled by atom transfer radical polymerization

DEFF Research Database (Denmark)

Jankova, Katja; Hvilsted, Søren

2005-01-01

Block copolymers based on poly(pentafluorostyrene), PFS, in various numbers and of different lengths, and polystyrene are prepared by atom transfer radical polymerization (ATRP). Di- and triblock copolymers with varying amounts of PFS were synthesized employing either I phenylethylbromide or 1,4-...

Controlled specific placement of nanoparticles into microdomains of block copolymer thin films

Energy Technology Data Exchange (ETDEWEB)

Bae, Joonwon, E-mail: joonwonbae@gmail.com [Department of Applied Chemistry, Dongduk Women' s University, Seoul 136-714 (Korea, Republic of); Kim, Jungwook [Department of Chemical and Biomolecular Engineering, Sogang University, Seoul 121-742 (Korea, Republic of); Park, Jongnam, E-mail: jnpark@unist.ac.kr [Interdisciplinary School of Green Energy, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798 (Korea, Republic of)

2014-07-01

Conceptually attractive hybrid materials composed of nanoparticles and elegant block copolymers have become important for diverse applications. In this work, controlled specific placement of nanoparticles such as gold (Au) and titania (TiO{sub 2}) into microphase separated domains in poly(styrene)-b-poly(2-vinylpyridine) (PS-b-P2VP) block copolymer thin films was demonstrated. The effect of nanoparticle surface functionality on the spatial location of particles inside polymer film was observed by transmission electron microscopy. It was revealed that the location of nanoparticles was highly dependent on the surface ligand property of nanoparticle. In addition, the microphase separation behavior of thin block copolymer film was also affected by the nanoparticle surface functional groups. This study might provide a way to understand the properties and behaviors of numerous block copolymer/nanoparticle hybrid systems. - Highlights: • Controlled location of nanoparticles in the block copolymer matrix • Tailoring surface functionality of metal nanocrystals • Fabrication of homogeneous nanocomposites using organic inorganic components • Possibility for the preparation of nanohybrids.

Controlled specific placement of nanoparticles into microdomains of block copolymer thin films

International Nuclear Information System (INIS)

Bae, Joonwon; Kim, Jungwook; Park, Jongnam

2014-01-01

Conceptually attractive hybrid materials composed of nanoparticles and elegant block copolymers have become important for diverse applications. In this work, controlled specific placement of nanoparticles such as gold (Au) and titania (TiO 2 ) into microphase separated domains in poly(styrene)-b-poly(2-vinylpyridine) (PS-b-P2VP) block copolymer thin films was demonstrated. The effect of nanoparticle surface functionality on the spatial location of particles inside polymer film was observed by transmission electron microscopy. It was revealed that the location of nanoparticles was highly dependent on the surface ligand property of nanoparticle. In addition, the microphase separation behavior of thin block copolymer film was also affected by the nanoparticle surface functional groups. This study might provide a way to understand the properties and behaviors of numerous block copolymer/nanoparticle hybrid systems. - Highlights: • Controlled location of nanoparticles in the block copolymer matrix • Tailoring surface functionality of metal nanocrystals • Fabrication of homogeneous nanocomposites using organic inorganic components • Possibility for the preparation of nanohybrids

Synthesis, Characterization and Photoinduction of Optical Anisotropy in Liquid Crystalline Diblock Azo-Copolymers

DEFF Research Database (Denmark)

Forcén, P; Oriol, L; Sánchez, C

2007-01-01

Diblock copolymers with polymethyl methacrylate and side chain liquid crystalline WC) azopolymethacrylate blocks were synthesized by atom transfer radical polymerization (ATRP). The azobeazene content in these copolymers ranges from 52 to 7 wt %. For an azo conteat dowri to 20% they exhibit a LC...... anisotropy induced in these films by illumination with linearly polarized 488 nm light was studied and the resuits compared with those of the azo homopolymer and of a random copolymer with a similar composition. The formation of azo aggregates inside the azo blocks is strongly reduced in going from...... the homopolymer to the copolymers. Photoinduced azo orientation perpendicular to the 488 nm light polarization was found in aH the polymers. The orientational order parameter is very similar in the homopolymer and in the block copolymers with an azo content down to 20 wt %, while it is much lower in the random...

Synthesis and photooxidation of styrene copolymer bearing camphorquinone pendant groups

Science.gov (United States)

Moszner, Norbert; Lukáč, Ivan

2012-01-01

Summary (±)-10-Methacryloyloxycamphorquinone (MCQ) was synthesized from (±)-10-camphorsulfonic acid either by a known seven-step synthetic route or by a novel, shorter five-step synthetic route. MCQ was copolymerized with styrene (S) and the photochemical behavior of the copolymer MCQ/S was compared with that of a formerly studied copolymer of styrene with monomers containing the benzil (BZ) moiety (another 1,2-dicarbonyl). Irradiation (λ > 380 nm) of aerated films of styrene copolymers with monomers containing the BZ moiety leads to the insertion of two oxygen atoms between the carbonyl groups of BZ and to the formation of benzoyl peroxide (BP) as pendant groups on the polymer backbone. An equivalent irradiation of MCQ/S led mainly to the insertion of only one oxygen atom between the carbonyl groups of camphorquinone (CQ) and to the formation of camphoric anhydride (11) covalently bound to the polymer backbone. While the decomposition of pendant BP groups formed in irradiated films of styrene copolymers with pendant BZ groups leads to crosslinking, only small molecular-weight changes in irradiated MCQ/S were observed. PMID:22509202

Bacteriophytochromes control conjugation in Agrobacterium fabrum.

Science.gov (United States)

Bai, Yingnan; Rottwinkel, Gregor; Feng, Juan; Liu, Yiyao; Lamparter, Tilman

2016-08-01

Bacterial conjugation, the transfer of single stranded plasmid DNA from donor to recipient cell, is mediated through the type IV secretion system. We performed conjugation assays using a transmissible artificial plasmid as reporter. With this assay, conjugation in Agrobacterium fabrum was modulated by the phytochromes Agp1 and Agp2, photoreceptors that are most sensitive in the red region of visible light. In conjugation studies with wild-type donor cells carrying a pBIN-GUSINT plasmid as reporter that lacked the Ti (tumor inducing) plasmid, no conjugation was observed. When either agp1(-) or agp2(-) knockout donor strains were used, plasmid DNA was delivered to the recipient, indicating that both phytochromes suppress conjugation in the wild type donor. In the recipient strains, the loss of Agp1 or Agp2 led to diminished conjugation. When wild type cells with Ti plasmid and pBIN-GUS reporter plasmid were used as donor, a high rate of conjugation was observed. The DNA transfer was down regulated by red or far-red light by a factor of 3.5. With agp1(-) or agp2(-) knockout donor cells, conjugation in the dark was about 10 times lower than with the wild type donor, and with the double knockout donor no conjugation was observed. These results imply that the phytochrome system has evolved to inhibit conjugation in the light. The decrease of conjugation under different temperature correlated with the decrease of phytochrome autophosphorylation. Copyright © 2015 Elsevier B.V. All rights reserved.

Thermal and radiochemical degradation of some PAN copolymers

Energy Technology Data Exchange (ETDEWEB)

Jipa, S. [INCDIE, ICPE CA, 313 Splaiul Unirii, P.O. Box 149, Bucharest 030138 (Romania); ' Valachia' University of Targoviste, 18-22 Unirii Av., Targoviste 130082 (Romania); Zaharescu, T. [' Valachia' University of Targoviste, 18-22 Unirii Av., Targoviste 130082 (Romania)], E-mail: traian_zaharescu@yahoo.com; Setnescu, R. [INCDIE, ICPE CA, 313 Splaiul Unirii, P.O. Box 149, Bucharest 030138 (Romania); ' Valachia' University of Targoviste, 18-22 Unirii Av., Targoviste 130082 (Romania); Dragan, E.S.; Dinu, M.V. [' Petru Poni' Institute of Macromolecular Chemistry, Iasi 700487 (Romania)

2008-12-01

Polyacrylonitrile (PAN) and some copolymers of acrylonitrile with divinylbenzene (AN-DVB) were investigated by the characterization of their thermal and radiation stabilities. The contribution of DVB to the thermal stability of PAN by the modification in the amount of unsaturated hydrocarbon between 6 and 20% was revealed by the evaluation of oxidation induction periods and required activation energies. The exposure of these materials to the action of {gamma}-radiation points out the higher stability of copolymers (AN-DVB) in comparison to the relative stability of PAN.

21 CFR 175.365 - Vinylidene chloride copolymer coatings for polycarbonate film.

Science.gov (United States)

2010-04-01

... polycarbonate film. 175.365 Section 175.365 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH... chloride copolymer coatings for polycarbonate film. Vinylidene chloride copolymer coatings identified in this section and applied on polycarbonate film may be safely used as food-contact surfaces, in...

Polymers for Protein Conjugation

Directory of Open Access Journals (Sweden)

Gianfranco Pasut

2014-01-01

Full Text Available Polyethylene glycol (PEG at the moment is considered the leading polymer for protein conjugation in view of its unique properties, as well as to its low toxicity in humans, qualities which have been confirmed by its extensive use in clinical practice. Other polymers that are safe, biodegradable and custom-designed have, nevertheless, also been investigated as potential candidates for protein conjugation. This review will focus on natural polymers and synthetic linear polymers that have been used for protein delivery and the results associated with their use. Genetic fusion approaches for the preparation of protein-polypeptide conjugates will be also reviewed and compared with the best known chemical conjugation ones.

Fabrication of supramolecular star-shaped amphiphilic copolymers for ROS-triggered drug release.

Science.gov (United States)

Zuo, Cai; Peng, Jinlei; Cong, Yong; Dai, Xianyin; Zhang, Xiaolong; Zhao, Sijie; Zhang, Xianshuo; Ma, Liwei; Wang, Baoyan; Wei, Hua

2018-03-15

Star-shaped copolymers with branched structures can form unimolecular micelles with better stability than the micelles self-assembled from conventional linear copolymers. However, the synthesis of star-shaped copolymers with precisely controlled degree of branching (DB) suffers from complicated sequential polymerizations and multi-step purification procedures, as well as repeated optimizations of polymer compositions. The use of a supramolecular host-guest pair as the block junction would significantly simplify the preparation. Moreover, the star-shaped copolymer-based unimolecular micelle provides an elegant solution to the tradeoff between extracellular stability and intracellular high therapeutic efficacy if the association/dissociation of the supramolecular host-guest joint can be triggered by the biologically relevant stimuli. For this purpose, in this study, a panel of supramolecular star-shaped amphiphilic block copolymers with 9, 12, and 18 arms were designed and fabricated by host-guest complexations between the ring-opening polymerization (ROP)-synthesized star-shaped poly(ε-caprolactone) (PCL) with 3, 4, and 6 arms end-capped with ferrocene (Fc) (PCL-Fc) and the atom transfer radical polymerization (ATRP)-produced 3-arm poly(oligo ethylene glycol) methacrylates (POEGMA) with different degrees of polymerization (DPs) of 24, 30, 47 initiated by β-cyclodextrin (β-CD) (3Br-β-CD-POEGMA). The effect of DB and polymer composition on the self-assembled properties of the five star-shaped copolymers was investigated by dynamic light scattering (DLS), transmission electron microscopy (TEM), and fluorescence spectrometery. Interestingly, the micelles self-assembled from 12-arm star-shaped copolymers exhibited greater stability than the 9- and 18-arm formulations. The potential of the resulting supramolecular star-shaped amphiphilic copolymers as drug carriers was evaluated by an in vitro drug release study, which confirmed the ROS-triggered accelerated drug

Study of the Pyrrol/Diphenylamine Copolymer by FT-IR spectroscopy and conductivity

Directory of Open Access Journals (Sweden)

Carlos Alberto Perez

2004-01-01

Full Text Available The main goal of this study was to analyze the physical properties of the copolymer formed by the electrochemical deposition of the polydiphenylamine (PDPA on polypyrrole (Ppy and Ppy on PDPA, in different conditions, through the characterization of the materials formed by the resonant Raman, FT-IR and conductivity techniques. The interactions among the species which are present in the new copolymer structure and the changes in electronic conductivity, were verified. The copolymer was also synthesized electrochemically in the presence of iodide species and the material was characterized by FT-IR spectroscopy and conductivity. The role of the dopant was studied in the process of charge transfer between the copolymer-dopant, acting in the stabilization of the species in the polymer backbone and the increase of the electronic conductivity.

Electrosyntheses and characterizations of a new soluble conducting copolymer of 5-cyanoindole and 3,4-ethylenedioxythiophene

International Nuclear Information System (INIS)

Nie Guangming; Qu Liangyan; Xu Jingkun; Zhang Shusheng

2008-01-01

The copolymerization of 5-cyanoindole (CNIn) and 3,4-ethylenedioxythiophene (EDOT) was successfully performed electrochemically in acetonitrile containing tetrabutylammonium tetrafluoroborate by direct oxidation of monomer mixtures. The electrochemical properties of the copolymers were studied by cyclic voltammetry. The influence of applied polymerization potential on the synthesis of copolymer was investigated. This novel copolymer owns the advantages of poly(5-cyanoindole) (PCNIn) and poly(3,4-ethylenedioxythiophene) (PEDOT), i.e., good redox activity, good thermal stability and high conductivity. The copolymer was soluble in dimethyl sulfoxide. The fluorescence spectra indicate that the copolymer is a good blue-light emitter. The structure and morphology of the copolymers were investigated by UV-vis, infrared spectroscopy, 1 H NMR spectra and scanning electron microscopy (SEM), respectively

Photodegradable neutral-cationic brush block copolymers for nonviral gene delivery.

Science.gov (United States)

Hu, Xianglong; Li, Yang; Liu, Tao; Zhang, Guoying; Liu, Shiyong

2014-08-01

We report on the fabrication of a photodegradable gene-delivery vector based on PEO-b-P(GMA-g-PDMAEMA) neutral-cationic brush block copolymers that possess cationic poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) brushes for DNA compaction, poly(ethylene oxide) (PEO) as a hydrophilic block, and poly(glycidyl methacrylate) (PGMA) as the backbone. The PEO-b-P(GMA-g-PDMAEMA) copolymers were synthesized through the combination of reversible addition-fragmentation transfer (RAFT) polymerization and postmodification. A photocleavable PEO-based macroRAFT agent was first synthesized; next, the PEO-b-PGMA block copolymer was prepared by RAFT polymerization of GMA; this was followed by a click reaction to introduce the RAFT initiators on the side chains of the PGMA block; then, RAFT polymerization of DMAEMA afforded the PEO-b-P(GMA-g-PDMAEMA) copolymer. The obtained neutral-cationic brush block copolymer could effectively complex plasmid DNA (pDNA) into nanoparticles at an N/P ratio (i.e., the number of nitrogen residues per DNA phosphate) of 4. Upon UV irradiation, pDNA could be released owing to cleavage of the pDNA-binding cationic PDMAEMA side chains as well as the nitrobenzyl ester linkages at the diblock junction point. In addition, in vitro gene transfection results demonstrated that the polyplexes could be effectively internalized by cells with good transfection efficiency, and the UV irradiation protocol could considerably enhance the efficiency of gene transfection. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Design of block copolymer membranes using segregation strength trend lines

KAUST Repository

Sutisna, Burhannudin

2016-05-18

Block copolymer self-assembly and non-solvent induced phase separation are now being combined to fabricate membranes with narrow pore size distribution and high porosity. The method has the potential to be used with a broad range of tailor-made block copolymers to control functionality and selectivity for specific separations. However, the extension of this process to any new copolymer is challenging and time consuming, due to the complex interplay of influencing parameters, such as solvent composition, polymer molecular weights, casting solution concentration, and evaporation time. We propose here an effective method for designing new block copolymer membranes. The method consists of predetermining a trend line for the preparation of isoporous membranes, obtained by computing solvent properties, interactions and copolymer block sizes for a set of successful systems and using it as a guide to select the preparation conditions for new membranes. We applied the method to membranes based on poly(styrene-b-ethylene oxide) diblocks and extended it to newly synthesized poly(styrene-b-2-vinyl pyridine-b-ethylene oxide) (PS-b-P2VP-b-PEO) terpolymers. The trend line method can be generally applied to other new systems and is expected to dramatically shorten the path of isoporous membrane manufacture. The PS-b-P2VP-b-PEO membrane formation was investigated by in situ Grazing Incident Small Angle X-ray Scattering (GISAXS), which revealed a hexagonal micelle order with domain spacing clearly correlated to the membrane interpore distances.

Relaxation processes in a lower disorder order transition diblock copolymer

International Nuclear Information System (INIS)

Sanz, Alejandro; Ezquerra, Tiberio A.; Nogales, Aurora; Hernández, Rebeca; Sprung, Michael

2015-01-01

The dynamics of lower disorder-order temperature diblock copolymer leading to phase separation has been observed by X ray photon correlation spectroscopy. Two different modes have been characterized. A non-diffusive mode appears at temperatures below the disorder to order transition, which can be associated to compositional fluctuations, that becomes slower as the interaction parameter increases, in a similar way to the one observed for diblock copolymers exhibiting phase separation upon cooling. At temperatures above the disorder to order transition T ODT , the dynamics becomes diffusive, indicating that after phase separation in Lower Disorder-Order Transition (LDOT) diblock copolymers, the diffusion of chain segments across the interface is the governing dynamics. As the segregation is stronger, the diffusive process becomes slower. Both observed modes have been predicted by the theory describing upper order-disorder transition systems, assuming incompressibility. However, the present results indicate that the existence of these two modes is more universal as they are present also in compressible diblock copolymers exhibiting a lower disorder-order transition. No such a theory describing the dynamics in LDOT block copolymers is available, and these experimental results may offer some hints to understanding the dynamics in these systems. The dynamics has also been studied in the ordered state, and for the present system, the non-diffusive mode disappears and only a diffusive mode is observed. This mode is related to the transport of segment in the interphase, due to the weak segregation on this system

Low molecular weight block copolymers as plasticizers for polystyrene

DEFF Research Database (Denmark)

Hansen, Kristoffer Karsten; Nielsen, Charlotte Juel; Hvilsted, Søren

2005-01-01

/mol and minimum polystyrene content of 50 w/w%, which by us is predicted as the limits for solubility of polystyrene-b-alkyl in polystyrene. DSC showed polystyrene was plasticized, as seen by a reduction in glass transition temperature, by block copolymers consisting of a polystyrene block with molecular weight...... of approximately 1 kg/mol and an alkyl block with a molecular weight of approximately of 0.3 kg/mol. The efficiency of the block copolymers as plasticizers increases with decreasing molecular weight and polystyrene content. In addition, polystyrene-b-alkyl is found to be an efficient plasticizer also...... for polystyrene-b-polyisoprene-b-polystyrene (SIS) block copolymers. The end use properties of SIS plasticized with polystyrene-b-alkyl, measured as tensile strength, is higher than for SIS plasticized with dioctyl adipate. The polystyrene-b-polybutadiene-b-polystyrene and polystyrene-bpoly(propylene glycol...

Creating surfactant nanoparticles for block copolymer composites through surface chemistry.

Science.gov (United States)

Kim, Bumjoon J; Bang, Joona; Hawker, Craig J; Chiu, Julia J; Pine, David J; Jang, Se Gyu; Yang, Seung-Man; Kramer, Edward J

2007-12-04

A simple strategy to tailor the surface of nanoparticles for their specific adsorption to and localization at block copolymer interfaces was explored. Gold nanoparticles coated by a mixture of low molecular weight thiol end-functional polystyrene (PS-SH) (Mn = 1.5 and 3.4 kg/mol) and poly(2-vinylpyridine) homopolymers (P2VP-SH) (Mn = 1.5 and 3.0 kg/mol) were incorporated into a lamellar poly(styrene-b-2-vinylpyridine) diblock copolymer (PS-b-P2VP) (Mn = 196 kg/mol). A library of nanoparticles with varying PS and P2VP surface compositions (FPS) and high polymer ligand areal chain densities was synthesized. The location of the nanoparticles in the PS-b-P2VP block copolymer was determined by transmission electron microscopy. Sharp transitions in particle location from the PS domain to the PS/P2VP interface, and subsequently to the P2VP domain, were observed at FPS = 0.9 and 0.1, respectively. This extremely wide window of FPS values where the polymer-coated gold nanoparticles adsorb to the interface suggests a redistribution of PS and P2VP polymers on the Au surface, inducing the formation of amphiphilic nanoparticles at the PS/P2VP interface. In a second and synthetically more challenging approach, gold nanoparticles were covered with a thiol terminated random copolymer of styrene and 2-vinylpyridine synthesized by RAFT polymerization. Two different random copolymers were considered, where the molecular weight was fixed at 3.5 kg/mol and the relative incorporation of styrene and 2-vinylpyridine repeat units varied (FPS = 0.52 and 0.40). The areal chain density of these random copolymers on Au is unfortunately not high enough to preclude any contact between the P2VP block of the block copolymer and the Au surface. Interestingly, gold nanoparticles coated by the random copolymer with FPS = 0.4 were dispersed in the P2VP domain, while those with FPS = 0.52 were located at the interface. A simple calculation for the adsorption energy to the interface of the nanoparticles

Modeling of emulsion copolymer microstructure

NARCIS (Netherlands)

van Doremaele, G.H.J.; Herk, van A.M.; German, A.L.

1992-01-01

A model is developed to describe stages II and III of batch emulsion copolymn., and its predictive capabilities are investigated by application to the system styrene-Me acrylate. The main reaction site is the monomer-swollen polymer particle. Copolymn. rate and copolymer microstructure (molar

Light scattering from block copolymer melts near the order-disorder transition

Czech Academy of Sciences Publication Activity Database

Štěpánek, Petr; Lodge, T. P.; Bates, F. S.

1994-01-01

Roč. 2, - (1994), s. 110 ISSN 0009-2347. [Symposium Block Copolymer Dynamics, Chain Dynamics of Block Copolymers: Dynamics near the Ordering Transition. San Diego, 13.03.1994-18.03.1994] R&D Projects: GA AV ČR IA45023 Impact factor: 0.331, year: 1994

Design of block-copolymer-based micelles for active and passive targeting

NARCIS (Netherlands)

Lebouille, Jérôme G J L; Leermakers, Frans A M; Cohen Stuart, Martien A.; Tuinier, Remco

2016-01-01

A self-consistent field study is presented on the design of active and passive targeting block-copolymeric micelles. These micelles form in water by self-assembly of triblock copolymers with a hydrophilic middle block and two hydrophobic outer blocks. A minority amount of diblock copolymers with the

Design of block-copolymer-based micelles for active and passive targeting

NARCIS (Netherlands)

Lebouille, Jérôme G.J.L.; Leermakers, Frans A.M.; Cohen Stuart, Martien A.; Tuinier, Remco

2016-01-01

A self-consistent field study is presented on the design of active and passive targeting block-copolymeric micelles. These micelles form in water by self-assembly of triblock copolymers with a hydrophilic middle block and two hydrophobic outer blocks. A minority amount of diblock copolymers with

Improving Photovoltaic Performance of a Fused-Ring Azepinedione Copolymer via a D-A-A Design.

Science.gov (United States)

Zhang, Honghong; Li, Ting; Xiao, Zuo; Lei, Zhongli; Ding, Liming

2018-04-01

Two conjugated copolymer donors, PTTABDT and PBTTABDT, based on a fused-ring azepinedione acceptor unit, 5-(2-octyldodecyl)-4H-thieno[2',3':4,5]thieno[3,2-c]thieno[2',3':4,5]thieno[2,3-e]azepine-4,6(5H)-dione (TTA), are prepared. PTTABDT possesses a conventional donor-acceptor (D-A) structure with one TTA in the repeat unit, while PBTTABDT has a D-A-A structure with two TTAs in the repeat unit. Compared with PTTABDT, PBTTABDT shows a deeper highest occupied molecular orbital (HOMO) level, a narrower bandgap, and a higher hole mobility, and exhibits better performance in bulk heterojunction solar cells. Power conversion efficiencies of 6.18% and 7.81% are achieved from PTTABDT:PC 71 BM and PBTTABDT:PC 71 BM solar cells, respectively. The higher performance of PBTTABDT:PC 71 BM solar cells results from the enhanced open-circuit voltage (V oc ) and short-circuit current density (  J sc ). © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Thin Films of Novel Linear-Dendritic Diblock Copolymers

Science.gov (United States)

Iyer, Jyotsna; Hammond, Paula

1998-03-01

A series of diblock copolymers with one linear block and one dendrimeric block have been synthesized with the objective of forming ultrathin film nanoporous membranes. Polyethyleneoxide serves as the linear hydrophilic portion of the diblock copolymer. The hyperbranched dendrimeric block consists of polyamidoamine with functional end groups. Thin films of these materials made by spin casting and the Langmuir-Blodgett techniques are being studied. The effect of the polyethylene oxide block size and the number and chemical nature of the dendrimer end group on the nature and stability of the films formed willbe discussed.

Polymers and block copolymers of fluorostyrenes by ATRP

DEFF Research Database (Denmark)

Hvilsted, Søren; Borkar, Sachin; Abildgaard, Lillian

2002-01-01

Fully or partly fluorinated polymers have many desirable and intriguing properties. In the framework of a larger program on design and control of new functional block copolymers we recently employed the Atom Transfer Radical Polymerization (ATRP) protocol on 2,3,4,5,6-pentafluorostyrene (FS). We...... materials based on 2,3,5,6-tetrafiuoro-4-methoxy-styrene (TFMS). TFMS homopolymers as well as diblock copolymers with FS are produced by ATRP. Both types of novel polymers were subsequently demethylated and different side chains introduced on the resulting hydroxy sites....

Monte Carlo studies on the interfacial properties and interfacial structures of ternary symmetric blends with gradient copolymers.

Science.gov (United States)

Sun, Dachuan; Guo, Hongxia

2012-08-09

Using Monte Carlo simulation methods, the effects of the comonomer sequence distribution on the interfacial properties (including interfacial tension, interfacial thickness, saturated interfacial area per copolymer, and bending modulus) and interfacial structures (including chain conformations and comonomer distributions of the simulated copolymers at the interfaces) of a ternary symmetric blend containing two immiscible homopolymers and one gradient copolymer are investigated. We find that copolymers with a larger composition gradient width have a broader comonomer distribution along the interface normal, and hence more pronouncedly enlarge the interfacial thickness and reduce the interfacial tension. Furthermore, the counteraction effect, which arises from the tendency of heterogeneous segments in gradient copolymers to phase separate and enter their miscible phases to reduce the local enthalpy, decreases the stretching of copolymers along the interface normal direction. As a result, copolymers with a larger width of gradient composition can occupy a larger interfacial area and form softer monolayers at saturation and are more efficient in facilitating the formation of bicontinuous microemulsions. Additionally, chain length ratio, segregation strength, and interactions between homopolymers and copolymers can alter the interfacial character of gradient copolymers. There exists a strong coupling between the comonomer sequence distribution, chain conformation, and interfacial properties. Especially, bending modulus is mainly determined by the complicated interplay of interfacial copolymer density and interfacial chain conformation.

Barite formation in the presence of a commercial copolymer

Science.gov (United States)

Ruiz-Agudo, Cristina; Putnis, Christine; Ruiz-Agudo, Encarnacion; Putnis, Andrew

2015-04-01

Fluid composition can significantly modify the mechanisms of mineral formation. Particularly, the presence of organic additives in the aqueous media has been shown to alter the precipitation of minerals substantially (e.g. calcium carbonate, barium carbonate and barium sulfate). Despite the numerous studies dealing with barite precipitation and the influence of organic additives (e.g. Benton et al. 1993, Qi et al., 2000, Wang and Cölfen, 2006, Mavredaki et al., 2011), the details of the mechanism of barite formation in the presence of organic additives, particularly at the early stages of this process, are yet to be fully resolved. Here, we present observations on the initial stages of barite formation from aqueous solutions, as well as the alterations induced by a commercial copolymer (maleic acid/allyl sulfonic acid copolymer with phosphonate groups), commonly used as a scale inhibitor in oil recovery. Most synthetic commercial additives contain the same functional groups (e.g. carboxylate, phosphonate and/or sulfonate groups). Thus our work may help to understand the mechanism by which copolymers modify crystallization processes and aid in the selection of the most appropriate inhibitors for hindering or controlling barite scale formation. Barite scaling is one of the main problems in many industrial processes (such as, paper-making, chemical manufacturing, cement operations, off-shore oil extraction, geothermal energy production). Using Atomic Force Microscopy (AFM), we show that barite growth is significantly influenced by the presence of the copolymer. In its absence, barium sulfate growth occurs by 2D island nucleation and spreading. The addition of small amounts (0.1 ppm and 0.5 ppm) of the copolymer enhances 2D nucleation but blocks growth. Just 1 ppm of inhibitor is enough to block barite nucleation and growth by adsorption of a copolymer layer onto the barite surface. Transmission electron microscopy (TEM) was also used to gain better insights into the

Characteristics of immobilized aminoacylase from Aspergillus oryzae on macroporous copolymers.

Science.gov (United States)

He, B L; Jiang, P; Qiu, Y B

1990-01-01

Aminoacylase from Aspergillus oryzae was adsorbed on functionallized macroporous copolymers where the enzyme showed excellent catalyzing activity and operation stability. Various factors which effect the activity of the immobilized aminoacylase such as temperature, pH and ionic strength were investigated. The continuous operation of the enzyme immobilized on macroporous copolymers was compared with that of the enzyme immobilized on DEAE-Sephadex.

Synthesis and Thermosensitive Behavior of Polyacrylamide Copolymers and Their Applications in Smart Textiles

Directory of Open Access Journals (Sweden)

Tao Chen

2015-05-01

Full Text Available We tuned the lower critical solution temperature (LCST of amphiphilic poly(N-isopropylacrylamide (PNIPAAm via copolymerization with a hydrophilic comonomer of N-hydroxymethyl acrylamide (NHMAAm. A series of copolymers P(NIPAAm-co-NHMAAm were synthesized by atom transfer radical polymerization (ATRP using CuBr/(N,N,N',N',N''-Pentamethyldiethylenetriamine (PMDETA as a catalyst system and 2-bromo ethyl isobutyrate (EBiB as an initiator. The copolymers were well characterized by Fourier transform infrared spectroscopy (FT-IR, 1H Nuclear magnetic resonance (NMR, and Thermogravimetric analysis (TGA. The copolymers followed a simple rule in their thermosensitive behaviors and have a linear increase in the LCST as a function of NHMAAm mol%. The thermosensitive properties of the copolymer films were investigated and demonstrated hydrophilic-hydrophobic transitions. Finally, the copolymer was grafted onto cotton fabrics using citric acid (CA as a crosslinking agent and sodium hypophosphite (SHP as a catalyst following a two dipping, two padding process. The large number of hydroxyl groups in the copolymer makes grafting convenient and firm. The grafted cotton fabrics show obvious thermosensitive behaviors. The results demonstrate that the cotton fabrics become more hydrophobic when the temperature is higher than the LCST. This study presents a valuable route towards temperature-responsive smart textiles and their potential applications.

Polarizability of DNA Block Copolymer Nanoparticles Observed by Electrostatic Force Microscopy

NARCIS (Netherlands)

Sowwan, Mukhles; Faroun, Maryam; Mentovich, Elad; Ibrahim, Imad; Haboush, Shayma; Alemdaroglu, Fikri Emrah; Kwak, Minseok; Richter, Shachar; Herrmann, Andreas

2010-01-01

In this study, DNA block copolymer (DBC) micelles with a polystyrene (PS) core and a single-stranded (ss) DNA shell were doped with ferrocene (Fc) molecules. Tapping mode atomic force microscopy (AFM) was used to study the morphology of the doped and undoped block copolymer aggregates. We show that

Cellulose-based graft copolymers prepared by simplified electrochemically mediated ATRP

Directory of Open Access Journals (Sweden)

P. Chmielarz

2017-02-01

Full Text Available Brush-shaped block copolymer with a dual hydrophilic poly(acrylic acid-block-poly(oligo(ethylene glycol acrylate (PAA-b-POEGA arms was synthesized for the first time via a simplified electrochemically mediated ATRP (seATRP under both constant potential electrolysis and constant current electrolysis conditions, utilizing only 30 ppm of catalyst complex. The polymerization conditions were optimized to provide fast reactions while employing low catalyst concentrations and preparation of cellulose-based brush-like copolymers with narrow molecular weight distributions. The results from proton nuclear magnetic resonance (1H NMR spectral studies support the formation of cellulose-based graft (copolymers. It is expected that these new polymer brushes may find application as pH- and thermo-sensitive drug delivery systems.

Polydimethylsiloxane-polymethacrylate block copolymers tethering quaternary ammonium salt groups for antimicrobial coating

Energy Technology Data Exchange (ETDEWEB)

Qin, Xiaoshuai; Li, Yancai; Zhou, Fang; Ren, Lixia; Zhao, Yunhui, E-mail: zhaoyunhui@tju.edu.cn; Yuan, Xiaoyan

2015-02-15

Highlights: • A series of PDMS-b-QPDMAEMA block copolymers were synthesized via RAFT polymerization. • The composition and morphology of the copolymer films strongly depended on the content of QPDMAEMA. • Migration of QPDMAEMA blocks toward surface was promoted when contacting with water. • Heterogeneous film surfaces with higher N{sup +} content exhibited more obvious antimicrobial activity. - Abstract: Block copolymers PDMS-b-PDMAEMA were synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization involving N,N-dimethylaminoethyl methacrylate (DMAEMA) by using poly(dimethylsiloxane) (PDMS) macro-chain transfer agent. And, the tertiary amino groups in PDMAEMA were quaternized with n-octyliodide to provide quaternary ammonium salts (QPDMAEMA). The well-defined copolymers generated composition variation and morphology evolvement on film surfaces, which were characterized by X-ray photoelectron spectroscopy, atomic force microscopy, and contact angle measurements. The results indicated that the enrichment of QPDMAEMA brought about lower elemental ratios of Si/N on the film surfaces. The surface morphologies evolved with the variations of QPDMAEMA content, and the variation trend of film roughness was exactly opposite to that of water contact angle hysteresis. With regard to structure-antimicrobial relationships, the copolymer films had more evident antimicrobial activity against Gram-positive, Bacillus subtilis, and the surfaces with heterogeneous morphology and higher N{sup +} content presented better antimicrobial activity. The functionalized copolymers based PDMS and quaternary ammonium salts materials have the potential applications as antimicrobial coatings.

Responsive linear-dendritic block copolymers.

Science.gov (United States)

Blasco, Eva; Piñol, Milagros; Oriol, Luis

2014-06-01

The combination of dendritic and linear polymeric structures in the same macromolecule opens up new possibilities for the design of block copolymers and for applications of functional polymers that have self-assembly properties. There are three main strategies for the synthesis of linear-dendritic block copolymers (LDBCs) and, in particular, the emergence of click chemistry has made the coupling of preformed blocks one of the most efficient ways of obtaining libraries of LDBCs. In these materials, the periphery of the dendron can be precisely functionalised to obtain functional LDBCs with self-assembly properties of interest in different technological areas. The incorporation of stimuli-responsive moieties gives rise to smart materials that are generally processed as self-assemblies of amphiphilic LDBCs with a morphology that can be controlled by an external stimulus. Particular emphasis is placed on light-responsive LDBCs. Furthermore, a brief review of the biomedical or materials science applications of LDBCs is presented. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

SYNTHESIS OF AMPHIPHILIC COMB-SHAPED COPOLYMERS USED FOR SURFACE MODIFICATION OF PVDF MEMBRANES

Institute of Scientific and Technical Information of China (English)

徐又一

2009-01-01

The synthesis of a novel amphiphilic comb-shaped copolymer consisting of a main chain of styrene-(N-(4- hydroxyphenyl) maleimide)(SHMI) copolymer and poly(ethylene glycol) methyl ether methacrylate(PEGMA) side groups was achieved by atom transfer radical polymerization(ATRP).The amphiphilic copolymers were characterized by ~1H-NMR, Fourier transform infrared(FTIR) spectroscopy and gel permeation chromatography(GPC).From thermogravimetric analysis (TGA),the decomposition temperature of SHMI-g-PEGMA is low...

Design, synthesis, and characterization of lightly sulfonated multigraft acrylate-based copolymer superelastomers

Energy Technology Data Exchange (ETDEWEB)

Misichronis, Konstantinos [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Chemistry; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division; Wang, Weiyu [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS); Cheng, Shiwang [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division; Wang, Yangyang [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS); Shrestha, Umesh [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Chemistry; Dadmun, Mark D. [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Chemistry; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division; Mays, Jimmy W. [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Chemistry; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division; Saito, Tomonori [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division

2018-01-29

Multigraft copolymer superelastomers consisting of a poly(n-butyl acrylate) backbone and polystyrene side chains were synthesized and the viscoelastic properties of the non-sulfonated and sulfonated final materials were investigated using extensional rheology (SER3). The non-linear viscoelastic experiments revealed significantly increased true stresses (up to 10 times higher) after sulfonating only 2–3% of the copolymer while the materials maintained high elongation (<700%). The linear viscoelastic experiments showed that the storage and loss modulus are increased by sulfonation and that the copolymers can be readily tuned and further improved by increasing the number of branching points and the molecular weight of the backbone. Here, in this way, we show that by tuning not only the molecular characteristics of the multigraft copolymers but also their architecture and chemical interaction, we can acquire thermoplastic superelastomer materials with desired viscoelastic properties.

Kinetics of directed self-assembly of block copolymers on chemically patterned substrates

International Nuclear Information System (INIS)

Müller, Marcus; Li, Weihua; Rey, Juan Carlos Orozco; Welling, Ulrich

2015-01-01

Chemically patterned surfaces have been successfully employed to direct the kinetics of self-assembly of block copolymers into dense, periodic morphologies (”chemoepitaxy”). Significant efforts have been directed towards understanding the kinetics of structure formation and, particularly, the formation and annihilation of defects. In the present manuscript we use computer simulations of a soft, coarse-grained polymer model to study the kinetics of structure formation of lamellar-forming block copolymer thin films on a chemical pattern of lines and spaces. The case where the copolymer material replicates the surface pattern and the more subtle scenario of sparse guiding patterns are considered. Our simulation results highlight (1) the importance of the early stages of pattern-directed self-assembly that template the subsequent morphology and (2) the dependence of the free-energy landscape on the incompatibility between the two blocks of the copolymer. (paper)

Synthesis and characterization of functional acrylic copolymers via RAFT mini-emulsion polymerization

Science.gov (United States)

Yılmaz, Onur; Özkan, ćiǧdem Kılıçarislan; Yılmaz, Catalina N.; Yorgancıoǧlu, Ali; Özgünay, Hasan; Karavana, Hüseyin Ata

2017-12-01

Copolymers bearing reactive functional groups with controlled molecular weights are of importance since they can be used in many fields such as composites, coatings, membranes, catalysis, biology, optoelectronics, pharmaceuticals, etc. In the present study low molecular weight copolymers based on butyl acrylate (BA) and methyl methacrylate (MMA) in combination with reactive functional monomers of vinyl trietoxysilane (VTES), 3-trimetoxysilylpropyl methacrylate (TMSPMA) and glycidyl methacrylate (GMA) were synthesized via RAFT mini-emulsion technique using 2-cyano 2-propyldodecyldithiocarbonate as CTA agent. The results showed that the average molecular weights of copolymers were close to the theoretical values. On the other hand, PDI values were found to be higher than conventional RAFT polymers. The particle sizes of the latexes were small with very homogenous distributions and good stability. FTIR, H-NMR and TGA results verified the success of copolymer syntheses.

Applying thermosettable zwitterionic copolymers as general fouling-resistant and thermal-tolerant biomaterial interfaces.

Science.gov (United States)

Chou, Ying-Nien; Chang, Yung; Wen, Ten-Chin

2015-05-20

We introduced a thermosettable zwitterionic copolymer to design a high temperature tolerance biomaterial as a general antifouling polymer interface. The original synthetic fouling-resistant copolymer, poly(vinylpyrrolidone)-co-poly(sulfobetaine methacrylate) (poly(VP-co-SBMA)), is both thermal-tolerant and fouling-resistant, and the antifouling stability of copolymer coated interfaces can be effectively controlled by regulating the VP/SBMA composition ratio. We studied poly(VP-co-SBMA) copolymer gels and networks with a focus on their general resistance to protein, cell, and bacterial bioadhesion, as influenced by the thermosetting process. Interestingly, we found that the shape of the poly(VP-co-SBMA) copolymer material can be set at a high annealing temperature of 200 °C while maintaining good antifouling properties. However, while the zwitterionic PSBMA polymer gels were bioinert as expected, control of the fouling resistance of the PSBMA polymer networks was lost in the high temperature annealing process. A poly(VP-co-SBMA) copolymer network composed of PSBMA segments at 32 mol % showed reduced fibrinogen adsorption, tissue cell adhesion, and bacterial attachment, but a relatively higher PSBMA content of 61 mol % was required to optimize resistance to platelet adhesion and erythrocyte attachment to confer hemocompatibility to human blood. We suggest that poly(VP-co-SBMA) copolymers capable of retaining stable fouling resistance after high temperature shaping have a potential application as thermosettable materials in a bioinert interface for medical devices, such as the thermosettable coating on a stainless steel blood-compatible metal stent investigated in this study.

Thin Film Assembly of Spider Silk-like Block Copolymers

Science.gov (United States)

2011-01-01

Shipley, N. H.; Lewis, R. V. Int. J. Biol.Macromol. 1999, 24, 271. (c) Thiel, B. L.; Guess, K. B.; Viney, C. Biopolymers 1997, 41, 703. (13) Silk ...Film Assembly of Spider Silk -like Block Copolymers Sreevidhya T. Krishnaji,†,‡ Wenwen Huang,§ Olena Rabotyagova,†,‡ Eugenia Kharlampieva, ) Ikjun Choi...Received November 26, 2010 We report the self-assembly of monolayers of spider silk -like block copolymers. Langmuir isotherms were obtained for a series of

Novel block, graft and random copolymers for biomedical applications

DEFF Research Database (Denmark)

Javakhishvili, Irakli; Jankova Atanasova, Katja; Tanaka, Masaru

Despite the simple structure, poly(2-methoxyethyl acrylate) (PMEA) shows excellent blood compatibility [1]. Both the freezing-bound water (intermediate water: preventing the biocomponents from directly contacting the polymer surface) and non-freezing water on the polymer surface play important...... copolymers with MMA [4] utilizing ATRP. Here we present other block, graft and random copolymers of MEA intended for biomedical applications. These macromolecular architectures have been constructed by employing controlled radical polymerization methods such as RAFT and ATRP....

In-situ Polymerization of Polyaniline/Polypyrrole Copolymer using Different Techniques

Science.gov (United States)

Hammad, A. S.; Noby, H.; Elkady, M. F.; El-Shazly, A. H.

2018-01-01

The morphology and surface area of the poly(aniline-co-pyrrole) copolymer (PANPY) are important properties which improve the efficiency of the copolymer in various applications. In this investigation, different techniques were employed to produce PANPY in different morphologies. Aniline and pyrrole were used as monomers, and ammonium peroxydisulfate (APS) was used as an oxidizer with uniform molar ratio. Rapid mixing, drop-wise mixing, and supercritical carbon dioxide (ScCO2) polymerization techniques were appointed. The chemical structure, crystallinity, porosity, and morphology of the composite were distinguished by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Brunauer, Emmett and Teller (BET) analysis, and transmission electron microscopy (TEM) respectively. The characterization tests indicated that the polyaniline/polypyrrole copolymer was successfully prepared with different morphologies. Based on the obtained TEM, hollow nanospheres were formed using rapid mixing technique with acetic acid that have a diameter of 75 nm and thickness 26 nm approximately. Also, according to the XRD, the produced structures have a semi- crystalline structure. The synthesized copolymer with ScCO2-assisted polymerization technique showed improved surface area (38.1 m2/g) with HCl as dopant.

Water stale and structure analysis of Konjac irradiation copolymer

International Nuclear Information System (INIS)

Geng Shengrong; Xia Hezhou; Chen Xueling; Ye Lixiu; Hua Yuejin

2011-01-01

To study the absorption performance of Konjac-AA copolymer prepared by using irradiation, the water absorption capacity, sorbent speed and water keeping ability were determined, DSC and TEM analysis were used to investigate the water content and structure characters. The results showed that the largest water absorption speed was 16 g · -1 · min -1 at room temperature, and the largest water absorption was 400 times within 60 minutes. The water absorption was affected by granularity, temperature, ion content and ion type, especially the ion type. The water keeping ability was affected by temperature and time, which was up to 35% of absorbed water when the fully water absorbed copolymer was kept under room temperature for 15 d. The free and bounder water content which could be assimilated by the plants was 99.617%. The water stale copolymer has a three-dimensional spiral structure. (authors)

40 CFR 180.1162 - Acrylate polymers and copolymers; exemption from the requirement of a tolerance.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Acrylate polymers and copolymers... RESIDUES IN FOOD Exemptions From Tolerances § 180.1162 Acrylate polymers and copolymers; exemption from the requirement of a tolerance. (a) Acrylate polymers and copolymers are exempt from the requirement of a...

Influence of the content of hard segments on the properties of novel urethane-siloxane copolymers based on a poly(ε-caprolactone-b-poly(dimethylsiloxane-b-poly(ε- caprolactone triblock copolymer

Directory of Open Access Journals (Sweden)

Antić Vesna V.

2011-01-01

Full Text Available A series of novel thermoplastic urethane-siloxane copolymers (TPUSs based on a α,ω-dihydroxy-[poly(ε-caprolactone-bpoly( dimethylsiloxane-b-poly(ε-caprolactone] (α,ω-dihydroxy-PCLPDMS- PCL triblock copolymer, 4,4?-methylenediphenyl diisocyanate (MDI and 1,4-butanediol (BD was synthesized. The effects of the content (9-63 wt. % of hard urethane segments and their degree of polymerization on the properties of the segmented TPUSs were investigated. The structure, composition and hard segment degree of polymerization of the hard segments were examined using 1H- and quantitative 13C-NMR spectroscopy. The degree of crystallinity of the synthesized copolymers was determined using wide-angle X-ray scattering (WAXS. The surface properties were evaluated by measuring the water contact angle and water absorption. In the series of the TPUSs, the average degree of polymerization of the hard segments was varied from 1.2 to 14.4 MDI-BD units. It was found that average values from 3.8 to 14.4 MDI-BD units were effective segment lengths for crystallization of hard segments, which resulted in an increase in the degree of microphase separation of the copolymers. Spherulite-like superstructures were observed in copolymer films by scanning electron microscopy (SEM, which are believed to arise from the crystallization of the hard segments and/or PCL segments, depending on the content of the hard segments. The surface of the copolymers became more hydrophobic with increasing weight fraction of PDMS. The synthesized copolymers based on a PCL-PDMS-PCL segment showed good thermal stability, which increased with increasing content of soft PDMS segments, as was confirmed by the value of the starting temperature of thermal degradation.

Influence of copolymer architectures on adhesion and compatibilization of polymers at interfaces

Science.gov (United States)

Guo, Lantao

Adhesion and compatibilization of immiscible homopolymers by a variety of copolymer architectures were studied. The work is arranged into 5 chapters: In Chapter 1, an introduction to recent studies on improvement of adhesion and compatibilization of polymer blends using copolymers was made including the advantages and shortcomings of interfacial reinforcement by a diblock copolymer architecture. Emphasis is on the novel ways to improve adhesion at polymer interfaces by a variety of copolymer architectures, including physical entanglement and chemical modification and chemical bonding. In Chapter 2, a series of Polystyrene-Poly(methyl methacrylate) (PS-PMMA) graft copolymers were introduced to modify the PS and PMMA homopolymer interface and was found to increase the interfacial fracture toughness to a large extent, depending on the detailed architectural variables such as the graft number per chain, the lengths of the backbone and the grafts, and the total molecular weights of the graft copolymers. It was also found that there was an optimal number of grafts per chain which can be interpreted based on the graft length and inter-branch length of the backbone of the copolymer. Effect of in-situ grafting via a chemical reaction between Polystyrene-Poly(vinyl phenol) (PS-PSOH) and oxazoline containing Styrene-Acrylonitril (SAN) was also discussed compared with the physical grafting of a graft copolymer of different structural parameters. In Chapter 3, hydrogen bonding was utilized to toughen the interface between PS and PAA poly(acrylic acid)) or PMMA using a random copolymer architecture of Polystyrene-Poly(vinyl pyridine) (PS-PVP). It was shown that random copolymer architecture is not only economically feasible due to its low cost of producing but also very effective on adhesion because it not only overcomes the issue of micelle formation which is an unavoidable situation in the diblock and graft cases but the enhancement of adhesion is much higher utilizing a H

Fabrication of endothelial progenitor cell capture surface via DNA aptamer modifying dopamine/polyethyleneimine copolymer film

Energy Technology Data Exchange (ETDEWEB)

Li, Xin; Deng, Jinchuan; Yuan, Shuheng; Wang, Juan; Luo, Rifang; Chen, Si [Key Lab. of Advanced Technology for Materials of Education Ministry, Southwest Jiaotong University, Chengdu 610031 (China); School of Material Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Wang, Jin, E-mail: jinxxwang@263.net [Key Lab. of Advanced Technology for Materials of Education Ministry, Southwest Jiaotong University, Chengdu 610031 (China); Huang, Nan [Key Lab. of Advanced Technology for Materials of Education Ministry, Southwest Jiaotong University, Chengdu 610031 (China); School of Material Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China)

2016-11-15

Highlights: • The dopamine/PEI film with controlled amine density was successfully prepared. • The DNA aptamer was assembled onto the film via electrostatic incorporation. • The A@DPfilmscanspecificallyandeffectivelycaptureEPCs. • The A@DP film can support the survival of ECs, control the hyperplasia of SMCs. • The dynamic/co-culture models are useful for studying cells competitive adhesion. - Abstract: Endothelial progenitor cells (EPCs) are mainly located in bone marrow and circulate, and play a crucial role in repairmen of injury endothelium. One of the most promising strategies of stents designs were considered to make in-situ endothelialization in vivo via EPC-capture biomolecules on a vascular graft to capture EPCs directly from circulatory blood. In this work, an EPC specific aptamer with a 34 bases single strand DNA sequence was conjugated onto the stent surface via dopamine/polyethyleneimine copolymer film as a platform and linker. The assembled density of DNA aptamer could be regulated by controlling dopamine percentage in this copolymer film. X-ray photoelectron spectroscopy (XPS), water contact angle (WCA) and fluorescence test confirmed the successful immobilization of DNA aptamer. To confirm its biofunctionality and cytocompatibility, the capturing cells ability of the aptamer modified surface and the effects on the growth behavior of human umbilical vein endothelial cells (HUVECs), smooth muscle cells (SMCs) were investigated. The aptamer functionalized sample revealed a good EPC-capture ability, and had a cellular friendly feature for both EPC and EC growth, while not stimulated the hyperplasia of SMCs. And, the co-culture experiment of three types of cells confirmed the specificity capturing of EPCs to aptamer modified surface, rather than ECs and SMCs. These data suggested that this aptamer functionalized surface may have a large potentiality for the application of vascular grafts with targeted endothelialization.

Fabrication of endothelial progenitor cell capture surface via DNA aptamer modifying dopamine/polyethyleneimine copolymer film

International Nuclear Information System (INIS)

Li, Xin; Deng, Jinchuan; Yuan, Shuheng; Wang, Juan; Luo, Rifang; Chen, Si; Wang, Jin; Huang, Nan

2016-01-01

Highlights: • The dopamine/PEI film with controlled amine density was successfully prepared. • The DNA aptamer was assembled onto the film via electrostatic incorporation. • The A@DPfilmscanspecificallyandeffectivelycaptureEPCs. • The A@DP film can support the survival of ECs, control the hyperplasia of SMCs. • The dynamic/co-culture models are useful for studying cells competitive adhesion. - Abstract: Endothelial progenitor cells (EPCs) are mainly located in bone marrow and circulate, and play a crucial role in repairmen of injury endothelium. One of the most promising strategies of stents designs were considered to make in-situ endothelialization in vivo via EPC-capture biomolecules on a vascular graft to capture EPCs directly from circulatory blood. In this work, an EPC specific aptamer with a 34 bases single strand DNA sequence was conjugated onto the stent surface via dopamine/polyethyleneimine copolymer film as a platform and linker. The assembled density of DNA aptamer could be regulated by controlling dopamine percentage in this copolymer film. X-ray photoelectron spectroscopy (XPS), water contact angle (WCA) and fluorescence test confirmed the successful immobilization of DNA aptamer. To confirm its biofunctionality and cytocompatibility, the capturing cells ability of the aptamer modified surface and the effects on the growth behavior of human umbilical vein endothelial cells (HUVECs), smooth muscle cells (SMCs) were investigated. The aptamer functionalized sample revealed a good EPC-capture ability, and had a cellular friendly feature for both EPC and EC growth, while not stimulated the hyperplasia of SMCs. And, the co-culture experiment of three types of cells confirmed the specificity capturing of EPCs to aptamer modified surface, rather than ECs and SMCs. These data suggested that this aptamer functionalized surface may have a large potentiality for the application of vascular grafts with targeted endothelialization.

Optical phase conjugation

CERN Document Server

Fisher, Robert A

1983-01-01

This book appears at a time of intense activity in optical phase conjugation. We chose not to await the maturation of the field, but instead to provide this material in time to be useful in its development. We have tried very hard to elucidate and interrelate the various nonlinear phenomena which can be used for optical phase conjugation.

Copolymers of fluorinated polydienes and sulfonated polystyrene

Science.gov (United States)

Mays, Jimmy W [Knoxville, TN; Gido, Samuel P [Hadley, MA; Huang, Tianzi [Knoxville, TN; Hong, Kunlun [Knoxville, TN

2009-11-17

Copolymers of fluorinated polydienes and sulfonated polystyrene and their use in fuel cell membranes, batteries, breathable chemical-biological protective materials, and templates for sol-gel polymerization.

Synthesis and Characterization of Novel Magnetite Nanoparticle Block Copolymer Complexes

OpenAIRE

Zhang, Qian

2007-01-01

Superparamagnetic Magnetite (Fe3O4) nanoparticles were synthesized and complexed with carboxylate-functionalized block copolymers, and aqueous dispersions of the complexes were investigated as functions of their chemical and morphological structures. The block copolymer dispersants possessed either poly(ethylene oxide), poly(ethylene oxide-co-propylene oxide), or poly(ethylene oxide-b-propylene oxide) outer blocks, and all contained a polyurethane center block with pendant carboxylate functi...

The effect of copolymers on the interfaces in incompatible homopolymers blend: Molecular dynamics study

Science.gov (United States)

Ryu, Jiho; Lee, Won Bo

2015-03-01

Using molecular dynamics simulations the effect of copolymers as compatibilizer for reducing interfacial tension and enhancement of interfacial adhesion at the interface of thermodynamic unfavorable homopolymers blend is studied with block- and graft-copolymers. We have calculated local pressure tensor of system along the axis perpendicular to interface, varying bending potential energy of one part, which consist of just one kind of beads, of copolymer chain to examine the effect of stiffness of surfactin molecules. Here we consider symmetric diblock copolymer (f =1/2) having 1/2 N make of beads of type A and the other part made of beads of type B, and graft copolymer having backbone linear chain consist of 1/2 N beads of type of A and branched with two side-chain consist of 1/4 N beads of type B. All simulations were performed under the constant NPT ensemble at T* =1, ρ* ~0.85. Also we studied changes of effect of copolymers with increasing pairwise repulsive interaction potential between two beads of types A and B while homopolymers chain length are fixed, N =30. Chemical and Biomolecular Engineering, Sogang University, Seoul, South Korea.

Microphase separation behavior on the surfaces of PEG-MDI-PDMS multiblock copolymer coatings

International Nuclear Information System (INIS)

Fang Hongxia; Zhou Shuxue; Wu Limin

2006-01-01

A series of poly(ethylene glycol)(PEG)-4,4'-diphenylmethanediisocyanate(MDI)-poly(dimethylsiloxane) (PDMS) multiblock copolymers were synthesized by employing two-step growth polymerization technique. Atomic force microscopy (AFM) observed nanoscopically well-organized phase-separated surfaces consisting of hydrophilic domain from PEG and MDI segments and hydrophobic domain from PDMS segments even with 50 wt.% PDMS in the copolymer, and the multiblock copolymer coatings presented a surface free energy of as low as 6-8 mN m -1

Synthesis and luminescent properties of new conjugated polymers based on poly(p-phenylene vinylene)

Science.gov (United States)

Gurge, Ronald Matthew

The "push-pull" electronically substituted polymers poly(2 (5) -bromo-5 (2) -n-hexyloxy-1,4-phenylene vinylene), poly(2 (5) -chloro-5 (2) -n-hexyloxy-1,4-phenylene vinylene) and poly(2 (5) -fluoro-5 (2) -n-hexyloxy-1,4-phenylene vinylene) were synthesized by a soluble precursor method and were used to fabricate light emitting diode (LED) devices. Thermal elimination of the polyether precursors gives final conjugated polymers as flexible red films. Precursor polymers can be spin-cast from solutions onto indium/tin oxide (ITO) pretreated quartz plates, then thermally converted to the final red polymers. Light emitting diode fabrication is then completed by the thin film vapor deposition of calcium, followed by aluminum. LED devices of the "push-pull" polymers give light emission in the 620-635 nm range. Two fluorinated polymers, poly(2-fluoro-1,4-phenylene vinylene) and poly(2,5-difluoro-1,4-phenylene vinylene) were investigated for their electroluminescent (EL) properties. LED's using these materials as emissive layers show substantial EL wavelength shifts (560 nm and 600 nm, respectively) relative to emission from unsubstituted poly(1,4-phenylene vinylene) (565 nm). These differences in EL emission can be attributed to the electronic effects of fluorine substitution. Synthetic strategies were developed for copolymeric materials based on poly(1,4-phenylene vinylene). The alternating block copolymer, poly (1,8-octanedioxy-2,6-dimethoxy-1,4-phenylene-1,2-ethenylene-1,4-phenylene-1,2-ethenylene-1,4-phenylene-1,2-ethenylene- 3,5-dimethoxy-1,4-phenylene) was synthesized by a modified Wittig polymerization utilizing trialkyl phosphonium salts. This resulted in a regiospecific trans-olefination reaction when compared to polymeric materials synthesized through the use of common triaryl-phosphonium salts. Harsh post-Wittig isomerization procedures using Isb2 were bypassed as a result of the high trans-cis ratio of the final copolymer. It was fully characterized using the

Understanding the ordering mechanisms of self-assembled nanostructures of block copolymers during zone annealing

Energy Technology Data Exchange (ETDEWEB)

Cong, Zhinan; Zhang, Liangshun, E-mail: zhangls@ecust.edu.cn, E-mail: jlin@ecust.edu.cn; Wang, Liquan; Lin, Jiaping, E-mail: zhangls@ecust.edu.cn, E-mail: jlin@ecust.edu.cn [Shanghai Key Laboratory of Advanced Polymeric Materials, State Key Laboratory of Bioreactor Engineering, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China)

2016-03-21

A theoretical method based on dynamic version of self-consistent field theory is extended to investigate directed self-assembly behaviors of block copolymers subjected to zone annealing. The ordering mechanisms and orientation modulation of microphase-separated nanostructures of block copolymers are discussed in terms of sweep velocity, wall preference, and Flory-Huggins interaction parameter. The simulated results demonstrate that the long-range ordered nanopatterns are achieved by lowering the sweep velocity of zone annealing due to the incorporation of templated ordering of block copolymers. The surface enrichment by one of the two polymer species induces the orientation modulation of defect-free nanostructures through finely tuning the composition of block copolymers and the preference of walls. Additionally, the Flory-Huggins interaction parameters of block copolymers in the distinct regions are main factors to design the zone annealing process for creating the highly ordered nanostructures with single orientation.

Process for producing a novel copolymer. [electron beams

Energy Technology Data Exchange (ETDEWEB)

Oiwa, M; Matsumoto, A; Tojima, M; Matsumoto, K; Sasaki, H

1970-11-27

Diaryl oxalate present in a polymer not only decomposes at lower temperatures, but also provides for stronger free radicals initiating polymerization than diaryl oxalate present in a monomer. A copolymer of vinyl monomers is produced by providing a diaryl oxalate polymer or a diaryl oxalate monomer-co-vinyl monomer, decomposing them to release the diaryl oxalate units by heating or irradiating with radiation thereby copolymerizing the vinyl monomer with the polymer radicals by utilizing the diaryl oxalate unit. For example, a single diaryl oxalate polymer or a copolymer containing the diaryl oxalate polymer as a constituent of the copolymer are irradiated or heated with a vinyl monomer, i.e. methyl methacrylate, acrylnitrile, vinyl acetate, styrene etc., to form a copolymer without difficulty. In one of the examples, 500 g of diaryl oxalate monomer, 1,200 ml of benzene and 0.2 mol/l of benzoil peroxide as an initiator were mixed and polymerized in nitrogen gas at 70/sup 0/C for 8 hrs. From this polymerized solution, a polymer was deposited in methanol. The produced polymer had an iodin value of 77.7 with a yield of 35%. The gel content of the produced polymer was 98.9% for 10 Mrad. This polymer was dissolved in methyl methacrylate, thereafter filled in a mold and irradiated with electron beams of 2 MeV in nitrogen gas to harden it. The advantage of this process is that the polymerization is effected with low energy radiations at room temperature without requiring any catalyst.

Synthesis and characterization of polyester copolymers based on poly(butylene succinate) and poly(ethylene glycol)

International Nuclear Information System (INIS)

Zhou, Xiao-Ming

2012-01-01

A series of polyester copolymers was synthesized from 1,4-succinic acid with 1,4-butanediol and poly(ethylene glycol) through a two-step process of esterification and polycondensation in this article. The composition and physical properties of copolyesters were investigated via GPC, 1 HNMR, DSC and PLM. The copolymer composition was in good agreement with that expected from the feed composition of the reactants. The melting temperature (T m ), crystallization temperature (T c ), and crystallinity (X c ) of these copolyesters decreased gradually as the content of PEG unit increased. Otherwise, experimental results also showed that the contents of PEG in copolymers had an effect on the molecular weight, distribution, thermal properties, hydrolysis degradation properties, and crystalline morphology of polyester copolymers. - Graphical abstract: The composition of polyester copolymer was determined from the 1 H NMR spectra using the relative intensities of the proton peaks. As a sample, the 1 H NMR spectrum of polyester copolymer with 10 mol% of PEG is shown in Fig. 2: CO-(CH 2 ) 2 -CO; O-CH 2 - and C-(CH 2 ) 2 -C from the SA and BD unit at δ2.59; δ 4.08 and δ1.67; O-(CH 2 CH 2 ) n -O from the PEG unit at δ 3.61. The molar composition of polyester copolymer was measured as the area ratio of δ3.61/(δ4.08 + δ1.67) peak. The PEG unit is incorporated into the copolymers in an amount of about 9.12mol% less than that of the feed proportion. These results showed that the composition of the copolymers is in good agreement with that expected from the feed proportion. Highlights: ► The introduction of PEG unit changed the flexibility of PBS main chain. ► PEG unit did not alter the crystal form of PBS in copolymers. ► PEG unit hindered the formation of ring-banded spherulite morphology in copolymers. ► The copolyesters had good in vitro degradation performance. ► The composition ratio of PEG unit can adjust the in vitro degradation performance.

Copolymers of various architectures containing ethylene and 5-norbornen-2-yl derivatives

Science.gov (United States)

Diamanti, Steve Jon

Polyolefins are a class of materials with enormous economic impact. Tailoring of polyolefin bulk properties by synthetic control is a major focus of many industrial and academic research groups. Polar functionalities within the hydrophobic polyolefin backbone can change important properties, such as, toughness, adhesion, solvent resistance, blend compatibility with other functional polymers, and rheological properties. Functional polyolefin materials with block or graft architectures are the most desirable structures as the pure polyolefin block maintains its intrinsic properties. Our initial work elucidated a neutral nickel based catalyst system capable of catalyzing the "quasi-living" homopolymerization of ethylene and the "quasi-living" copolymerization of ethylene with 5-norbornen-2-yl acetate (NBA), a polar comonomer. Through testing the effect of several reaction variables on the copolymerization of ethylene with NBA it was found that changing ethylene pressure causes a large change in the content of NBA in the copolymer chain. This change in NBA content, in turn, drastically affects the physical and thermal properties of these polymers. Understanding the impact of such reaction variables on copolymer properties made it possible to design more sophisticated architectures. This catalytic system has since been used to synthesize block copolymers and tapered block copolymers of ethylene and NBA. Block copolymers of ethylene and NBA have been synthesized by a method utilizing ethylene pressure variation to create two distinct copolymeric blocks that are able to order into microphase-separated structures. The block structure of these materials has been proven by 1H-NMR spectroscopy, thermal analysis, GPC, AFM, and TEM. The synthesis, characterization, and bulk and thermal properties of tapered block copolymers containing ethylene and NBA, has also been performed. The final structure of the tapered block polymer is a polar amorphous chain (rich in NBA) on one

Gas-permeation properties of poly(ethylene oxide) poly(butylene terephthalate block copolymers

NARCIS (Netherlands)

Metz, S.J.; Mulder, M.H.V.; Wessling, Matthias

2004-01-01

This paper reports the gas-permeation properties of poly(ethylene oxide) (PEO) poly(butylene terephthalate) (PBT) segmented multiblock copolymers. These block copolymers allow a precise structural modification by the amount of PBT and the PEO segment length, enabling a systematic study of the

Controlled release of potassium chloride from radiation-polymerized copolymer matrices

International Nuclear Information System (INIS)

Yoshida, Masaru; Kumakura, Minoru; Kaetsu, Isao

1979-01-01

Release behavior of potassium chloride (KCl) from the flat circular copolymer composites, obtained by radiation-induced polymerization at low temperatures, was studied. The release rate agreed with the first-order kinetics based on the Noyes-Whitney equation in relation to the swelling of the composites. Release profiles of KCl from copolymer composites was affected by monomer composition between hydroxyethyl acrylate (HEA) and polyfunctional glass-forming monomers such as 2-hydroxyethyl methacrylate (HEMA), diethylene glycol dimethacrylate (DGDA), and trimethylolpropane trimethacrylate (TMPT) owing to change of swelling property of copolymers. The release rate decreased at HEA-poor composition in any system. In the case of hydrophobic comonomer system such as glycidyl methacrylate (GMA) and DGDA, release profile of KCl showed a minimum at 50% GMA-50% DGDA monomer composition. (author)

Pressure and temperature effects in homopolymer blends and diblock copolymers

DEFF Research Database (Denmark)

Frielinghaus, H.; Schwahn, D.; Mortensen, K.

1997-01-01

Thermal composition fluctuations in a homogeneous binary polymer blend and in a diblock copolymer were measured by small-angle neutron scattering as a function of temperature and pressure. The experimental data were analyzed with theoretical expressions, including the important effect of thermal...... fluctuations. Phase boundaries, the Flory-Huggins interaction parameter and the Ginzburg number were obtained. The packing of the molecules changes with pressure. Therefore, the degree of thermal fluctuation as a function of packing and temperature was studied. While in polymer blends packing leads, in some...... respects, to a universal behaviour, such behaviour is not found in diblock copolymers. It is shown that the Ginzburg number decreases with pressure sensitively in blends, while it is constant in diblock copolymers. The Ginzburg number is an estimation of the transition between the universality classes...

High-frequency ultrasound-responsive block copolymer micelle.

Science.gov (United States)

Wang, Jie; Pelletier, Maxime; Zhang, Hongji; Xia, Hesheng; Zhao, Yue

2009-11-17

Micelles of a diblock copolymer composed of poly(ethylene oxide) and poly(2-tetrahydropyranyl methacrylate) (PEO-b-PTHPMA) in aqueous solution could be disrupted by high-frequency ultrasound (1.1 MHz). It was found that, upon exposure to a high-intensity focused ultrasound (HIFU) beam at room temperature, the pH value of the micellar solution decreased over irradiation time. The infrared spectroscopic analysis of solid block copolymer samples collected from the ultrasound irradiated micellar solution revealed the formation of carboxylic acid dimers and hydroxyl groups. These characterization results suggest that the high-frequency HIFU beam could induce the hydrolysis reaction of THPMA at room temperature resulting in the cleavage of THP groups. The disruption of PEO-b-PTHPMA micelles by ultrasound was investigated by using dynamic light scattering, atomic force microscopy, and fluorescence spectroscopy. On the basis of the pH change, it was found that the disruption process was determined by a number of factors such as the ultrasound power, the micellar solution volume and the location of the focal spot of the ultrasound beam. This study shows the potential to develop ultrasound-sensitive block copolymer micelles by having labile chemical bonds in the polymer structure, and to use the high-frequency HIFU to trigger a chemical reaction for the disruption of micelles.

(Electro)Mechanical Properties of Olefinic Block Copolymers

Science.gov (United States)

Spontak, Richard

2014-03-01

Conventional styrenic triblock copolymers (SBCs) swollen with a midblock-selective oil have been previously shown to exhibit excellent electromechanical properties as dielectric elastomers. In this class of electroactive polymers, compliant electrodes applied as active areas to opposing surfaces of an elastomer attract each other, and thus compress the elastomer due to the onset of a Maxwell stress, upon application of an external electric field. This isochoric process is accompanied by an increase in lateral area, which yields the electroactuation strain (measuring beyond 300% in SBC systems). Performance parameters such as the Maxwell stress, transverse strain, dielectric breakdown, energy density and electromechanical efficiency are determined directly from the applied electric field and resulting electroactuation strain. In this study, the same principle used to evaluate SBC systems is extended to olefinic block copolymers (OBCs), which can be described as randomly-coupled multiblock copolymers that consist of crystallizable polyethylene hard segments and rubbery poly(ethylene-co-octene) soft segments. Considerations governing the development of a methodology to fabricate electroresponsive OBC systems are first discussed for several OBCs differing in composition and bulk properties. Evidence of electroactuation in selectively-solvated OBC systems is presented and performance metrics measured therefrom are quantitatively compared with dielectric elastomers derived from SBC and related materials.

Nonlinear optical measurements of conducting copolymers of aniline under CW laser excitation

Science.gov (United States)

Pramodini, S.; Poornesh, P.

2015-08-01

Synthesis and measurements of third-order optical nonlinearity and optical limiting of conducting copolymers of aniline are presented. Single beam z-scan technique was employed for the nonlinear optical studies. Continuous wave He-Ne laser operating at 633 nm was used as the source of excitation. Copolymer samples exhibited reverse saturable absorption (RSA) process. The nonlinear refraction studies depict that the copolymers exhibit self-defocusing property. The estimated values of βeff, n2 and χ(3) were found to be of the order of 10-2 cm/W, 10-5 esu and 10-7 esu respectively. Self-diffraction rings were observed due to refractive index change when exposed to the laser beam. A good optical limiting and clamping of power of ∼0.9 mW and ∼0.05 mW was observed. Therefore, copolymers of aniline emerge as a potential candidate for photonic device applications.