نتایج جستجو برای: block copolymers

تعداد نتایج: 164252  

2017
Milica Stanković Christine Hiemstra Hans de Waard Johan Zuidema Rob Steendam Henderik W. Frijlink Wouter L.J. Hinrichs

In this study, novel hydrophilic multiblock copolymers composed of semi-crystalline poly(ε-caprolactone) [PCL] blocks and amorphous blocks consisting of poly(D,Llactide) (PDLA) and poly(ethylene glycol) (PEG) [PDLA-PEG] were synthesized. The block ratio of these [PDLA-PEG]-b-[PCL] multiblock copolymers was varied and the degradation of implants prepared of these polymers by hot melt extrusion (...

2002
Janne Virtanen Françoise Winnik Susanna Holappa

Various thermally responsive block and graft copolymers based on poly(Nisopropylacrylamide) (PNIPA) have been synthesised. Poly(ethyleneoxides) (PEO) with different chain lengths were used as hydrophilic blocks and grafts. The graft copolymers were synthesised in two steps. Firstly, two functional copolymers were prepared by free radical polymerisation of N-isopropylacrylamide (NIPA) with eithe...

Journal: :Organic & biomolecular chemistry 2011
Ming Chen Matthias Häussler Graeme Moad Ezio Rizzardo

Approaches to the synthesis of block copolymers containing organic semiconductor segments (polythiophene, perylene diimide) by RAFT polymerization have been explored. A method involving transformation of a vinyl derivative to a macro-RAFT agent provides for the synthesis of block copolymers which are joined by a short non-hydrolysable linkage.

Journal: :Journal of the American Chemical Society 2004
Hany B Eitouni Nitash P Balsara

The thermodynamic interactions in poly(styrene-block-ferrocenyldimethylsilane) and poly(isoprene-block-ferrocenyldimethylsilane) copolymers were systematically tuned by oxidation of the ferrocene moieties with silver nitrate. Small-angle X-ray scattering experiments show that oxidizing 8% of the ferrocene moieties lowers the order-disorder transition temperature of the copolymers by as much as ...

2006
Sébastien Garnier André Laschewsky

Water-soluble, amphiphilic diblock copolymers were synthesized by reversible addition fragmentation chain transfer polymerization. They consist of poly(butyl acrylate) as hydrophobic block with a low glass transition temperature and three different nonionic water-soluble blocks, namely, the classical hydrophilic block poly(dimethylacrylamide), the strongly hydrophilic poly(acryloyloxyethyl meth...

Journal: :Langmuir : the ACS journal of surfaces and colloids 2011
Sreevidhya T Krishnaji Wenwen Huang Olena Rabotyagova Eugenia Kharlampieva Ikjun Choi Vladimir V Tsukruk Rajesh Naik Peggy Cebe David L Kaplan

We report the self-assembly of monolayers of spider silk-like block copolymers. Langmuir isotherms were obtained for a series of bioengineered variants of the spider silks, and stable monolayers were generated. Langmuir-Blodgett films were prepared by transferring the monolayers onto silica substrates and were subsequently analyzed by atomic force microscopy (AFM). Static contact angle measurem...

2010
Yan Guan Xiaofang Chen Hongyang Ma Zhihao Shen Xinhua Wan

Novel diblock copolymers based on poly(isobutyl methacrylate) (PiBMA) and poly[2,5di(isopropyloxycarbonyl)styrene] (PiPCS) were designed and prepared via consecutive atom transfer radical polymerization. They had relatively low molecular weight distributions and tunable molecular weights. The molecular characterization of the copolymers was performed with proton nuclear magnetic resonance spect...

Journal: :Journal of the American Chemical Society 2008
Ho Cheung Shum Jin-Woong Kim David A Weitz

We describe a versatile technique for fabricating monodisperse polymersomes with biocompatible and biodegradable diblock copolymers for efficient encapsulation of actives. We use double emulsion as a template for the assembly of amphiphilic diblock copolymers into vesicle structures. These polymersomes can be used to encapsulate small hydrophilic solutes. When triggered by an osmotic shock, the...

Background: Adapting controlled release technologies to the delivery of DNA has the great potential to overcome extracellular barriers that limit gene delivery. This study investigates the effect of different mass ratio of PLA: PEG in the various tri block poly (lactic acid)-poly (ethylene glycol) - Poly (lactic acid) copolymer (PLA-PEG-PLA) on the properties of the resulting nanoparticles. Me...

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