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

Copolymers of 2-(2-methoxyethoxy)ethyl methacrylate (poly(MEO(2)MA)) are regarded as bioinert replacements of poly(N-isopropylacrylamide) in some biomedical applications. Networks of poly(MEO(2)MA) 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(MEO(2)MA) and its networks — bare network and the network grafted with short poly(MEO(2)MA) chains. We show that the α process assigned to the segmental motions of poly(MEO(2)MA) 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. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00396-015-3517-8) contains supplementary material, which is available to authorized users.