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 m- 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 (?-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 (<100 nm), i.e. nanogel formation occurs. Temperature-sensitive microgels of PVME were synthesized by irradiation of the sphere-like phase-separated structure (above Tcr) in dilute aqueous solutions. Another nano-structured PVME hydrogels were obtained by electron beam lithography of dry PVME films onto silicon substrate. This technique allows to generate PVME pattern with lateral resolutions >150 nm.
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 (?-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 (<100 nm), i.e. nanogel formation occurs. Temperature-sensitive microgels of PVME were synthesized by irradiation of the sphere-like phase-separated structure (above Tcr) in dilute aqueous solutions. Another nano-structured PVME hydrogels were obtained by electron beam lithography of dry PVME films onto silicon substrate. This technique allows to generate PVME pattern with lateral resolutions >150 nm.