Synthesis of hydrogels with a gradient crosslinking structure by electron beam radiation to an aqueous solution of poly(sodium acrylate)

Abstract

Hydrogels were prepared by electron beam (EB) radiation to the aqueous solutions of poly(sodium acrylate) in the presence of potassium and ammonium peroxodisulfates. The effects of EB radiation dose, as well as polymer, and initiator concentrations on the formation of gels, were investigated. On the basis of the storage modulus, loss modulus, and complex viscosity of the isolated gels determined by rheological measurement, the relationship between the radiation conditions and the rheological properties of the gels was discussed. Furthermore, hydrogels with a gradient crosslinking structure in a depth direction were synthesized by controlling EB radiation dose.

Hydrogels for active photonics

“…Unlike conventional fabrications for nanostructures that involve etching, hydrogels can directly serve as the resist itself, enabling the direct formation of nanostructures. When an electron beam is exposed to a specific region of the hydrogel film, the high energy breaks the molecular bonds within the hydrogel, forming radicals, which leads to crosslinking of adjacent polymer chains 102 , 103 . After cross-linking, the structured hydrogels retain their intrinsic characteristics as hydrogels but become insoluble in solvents.…”