Cross-linking of poly(N-vinyl pyrrolidone) films by electron beam irradiation

Biocompatible hydrogels based on poly(N-vinyl pyrrolidone) (PVP) were synthesized by electron beam irradiation of the dry polymer under various conditions. Sol-gel analysis of the bulk gel (in mm range) gave a dose of gelation of 94 kGy. As seen for various other polymers, the network density rises with the increase in dose. At around 350 kGy, PVP began to decompose. Based on these observations, films in pm range on a silicon wafer were synthesized by electron beam irradiation. Due to irradiation, the films adhered irreversibly on the wafer. Their swelling behaviour was analyzed by ellipsometry. (c) 2007 Elsevier Ltd. All rights reserved.