Thermosensitive spontaneous gradient copolymers with block- and gradient-like features

July 2017 - Polymer Chemistry, The Royal Society of Chemistry

Reversible addition–fragmentation chain transfer (RAFT) copolymerization was used to prepare copolymers of N-isopropyl acrylamide (NIPAM) and vinyl acetate (VAc) with mole fractions of NIPAM ranging from 0.1 to 0.6 and targeted degrees of polymerization of 100 and 250. The measured kinetic parameters and obtained experimental results revealed that this copolymerization system leads to a “one pot” synthesis of amphiphilic gradient copolymers, which have thermoresponsive and self-assembly characteristics resembling those of the analogous block copolymers but with some intriguing differences. Their self-assembly behavior in water suggests the formation of dynamic aggregates which respond rapidly to changes in solubility as revealed by 1H NMR spectroscopy, in contrast to the kinetically frozen aggregates formed by block copolymers. Furthermore, despite their block-like composition profiles, these copolymers display a single and broad glass transition, as is typically found in linear gradient copolymers. The synthetic approach presented in this contribution could readily be adapted to other comonomer systems to provide an accessible and economic alternative to the conventional multi-step preparation of block copolymers.

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Thermosensitive spontaneous gradient copolymers with block- and gradient-like features *

Roberto Yañez-Macias,a,b Ihor Kulai,c Jens Ulbrich,b Turgay Yildirim,b,d Pelin Sungur,b,d Stephanie Hoeppener,b,d Ramiro Guerrero-Santos,a Ulrich S. Schubert, b,d Mathias Destarac,c Carlos Guerrero-Sanchez*b,d and Simon Harrisson *c

a. Centro de Investigación en Química Aplicada, Departamento de Síntesis de Polímeros, (CIQA), Boulevard Enrique Reyna No. 140, 25294 Saltillo, Mexico

b. Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstr. 10, D-07743 Jena, Germany. E-mail: [email protected]

c. Laboratoire des IMRCP, Université de Toulouse, CNRS UMR 5623, Université Paul Sabatier, 118 route de Narbonne, 31062 Toulouse Cedex 9, France. E-mail: [email protected]

d. Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, D-07743 Jena, Germany

* Electronic supplementary information (ESI) available. See DOI: 10.1039/ c7py00495h

Polymer Chemistry – April 2017
DOI: 10.1039/c7py00495h
This journal is © The Royal Society of Chemistry 2017

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