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Thermo-responsive polymer hydrogels attract a great attention because of their unique behavior in response to changes in the thermal environment. It is related to metastable intermolecular interactions resulting in volume phase transitions (VPT). The hydration of poly(2-(2-methoxyethoxy)ethyl methacrylate) (PMEO2MA)-based materials was studied by Raman spectroscopy and further supported by density functional theory calculations. Hydrogels based on random networks prepared via radiationinduced free radical polymerization and cross-linking were compared with hydrogels withmore regular structure formed by atom transfer radical polymerization. Two types of regular networks were studied: bare one and decorated by linear dangling chains. It was found that both, the total bound water surrounding the polymer chains (~11 H2O per polymer unit) and accessibility of C=O groups for water molecules, are independent of topology of PMEO2MA network. Contrarily, network architecture strongly influences C=O-water complex stability, which decreases in a following order: regular bare network, irregular bare network, regular decorated network. It was also shown that the stability of C=O-water complex is correlated with VPT temperature in PMEO2MA hydrogels. These studies prove a key role of polymer hydration in its thermo-responsive properties. Copyright © 2016 JohnWiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Electron beam irradiation of 2-(2-methoxyethoxy)ethyl methacrylate and ethylene glycol dimethacrylate mixtures leads to the formation of cross-linked structures that exhibit a gradient of cross-link density, as demonstrated by gel fraction, swelling and Differential Scanning Calorimetry analysis. The reason for observed phase separation is formation of the high molecular weight clusters and its precipitation before gelation dose. This effect can be controlled/influenced by absorbed dose and cross-linker concentration. [ABSTRACT FROM AUTHOR]

Abstract: The gradient (“transient”) systems are required for many biomedical applications, especially if the materials with different properties are to be joined without strong internal stresses. In this paper one step, radiation-induced synthesis of thermo-responsive hydrogels based on 2-(2-methoxyethoxy)ethyl methacrylate with gradient in crosslink density, has been presented. The influence of the monomer composition and synthesis procedure (irradiation dose and conditioning temperature) on the general properties of prepared gels has been discussed. It has been found that the properties of particular sections of the gel sample do not result from the differences in chemical structure, but from significantly different morphology. The explanation of the mechanism leading to gradient behavior of obtained gels has been proposed. The chemical structure of obtained products and morphology of synthesized hydrogels as well as general properties of products have been analyzed. [Copyright &y& Elsevier]