Nano-Structured Temperature-Sensitive Hydrogels Crosslinked by High-Energy Radiation

The radiation-induced crosslinking of water-soluble polymers is a suitable tool to synthesize hydrogels of various structures in small dimensions. The absolute size and the properties of the hydrogels were varied by changing the experimental parameters of the radiation crosslinking of poly(vinyl methyl ether). All the synthesized PVME structures have dimensions in the µm- or nm-range and showing temperature-sensitive swelling behavior. Higher molecular weight PVME with long-chain branches was obtained by the pre-irradiation of dilute and semi-dilute aqueous PVME solutions with low dose rates (γ-rays). In dilute aqueous PVME solutions the crosslinking reaction is shifted toward intermolecular crosslinking by high dose rates in short times (pulsed electron beam irradiation). The intramolecular linking neglects an increase in molecular weight but reduce the dimension (150 nm.