Evolution of high-temperature molecular relaxations in poly(2-(2-methoxyethoxy)ethyl methacrylate) upon network formation

Marcin Kozanecki; Marcin Pastorczak; Lidia Okrasa; Jacek Ulanski; Jeong Ae Yoon; Tomasz Kowalewski; Krzysztof Matyjaszewski; Kaloian Koynov

doi:10.1007/s00396-015-3517-8

Evolution of high-temperature molecular relaxations in poly(2-(2-methoxyethoxy)ethyl methacrylate) upon network formation

Colloid Polym Sci. 2015;293(5):1357-1367. doi: 10.1007/s00396-015-3517-8. Epub 2015 Jan 30.

Authors

Marcin Kozanecki¹, Marcin Pastorczak¹, Lidia Okrasa¹, Jacek Ulanski¹, Jeong Ae Yoon², Tomasz Kowalewski², Krzysztof Matyjaszewski², Kaloian Koynov³

Affiliations

¹ Department of Molecular Physics, Lodz University of Technology, Zeromskiego 116, 90-924 Lodz, Poland.
² Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213 USA.
³ Max Planck Institute for Polymer Research, Ackermannweg 10, 55021 Mainz, Germany.

Abstract

Copolymers of 2-(2-methoxyethoxy)ethyl methacrylate (poly(MEO₂MA)) are regarded as bioinert replacements of poly(N-isopropylacrylamide) in some biomedical applications. Networks of poly(MEO₂MA) of various architecture form thermo-responsive hydrogels. Here, we present dielectric and mechanical spectroscopy studies on segmental motions and network relaxation processes in linear poly(MEO₂MA) and its networks - bare network and the network grafted with short poly(MEO₂MA) chains. We show that the α process assigned to the segmental motions of poly(MEO₂MA) is independent on the polymer topology and the glass transition temperature, T_g, associated with this process equals 235-236 K for all investigated systems. The α' relaxation observed above T_g by dynamical mechanical analysis is assigned to the sub-Rouse process. It strongly depends on the polymer network architecture and slows down by four orders of magnitude upon network formation.

Keywords: ATRP; Molecular relaxations; Poly(2-(2-methoxyethoxy)ethyl methacrylate); Polymer network.