Investigation of Optical and Electrical Properties of 2-acrylamido-2-methyl Propane Sulfonic Acid/2-Hydroxy Ethyl Methacrylate (AMPS/HEMA) Hydrogel Prepared by Gamma Irradiation

Hydrogels from either 2-acrylamido-2-methylpropane sulfonic acid (AMPS) or 2-hydroxyl ethyl methacrylate (HEMA) have been prepared by gamma radiation at irradiation dose of 10 kGy. Different volume ratio (v/v) of the starting materials were used to obtain crosslinked hydrogels of variable compositions and crosslink density. UV-VIS absorption spectra indicated that there is a variation in intensity as well as in optical energy gap with different doping levels. Therefore, values of direct and indirect energy gaps were calculated and discussed. The reflectance and transmittance were collected for the as-prepared hydrogels and analyzed in the incident photon energy range from 0.1 to 1.6 eV at a temperature range 300 to 500 K. The optical investigation revealed that the optical transition is directly allowed.