Distribution of water states within Poly(HEMA-co-HPMA)-based hydrogels

The distribution of water states within hydrogels is implicated in their biotechnical performance. Formulated synthetic hydrogels based on poly(2-hydroxyethylmethacrylate-co-N-(2-hydroxypropyl) methacrylamide) [poly(HEMA-co-HPMA)] of varying cross-linker concentration and monomer mole ratio were studied for their degree of hydration and water distribution. Cross-linker concentrations of 0.1, 0.5, 1.0, and 3.0 mol% tetraethylene glycol diacrylate (TEGDA) were studied when the HEMA:HPMA mole ratios were selected to be 1:0 and 4:1. Additionally, the cross-linker concentration of 1.0 mol% TEGDA was studied in detail when the HEMA:HPMA ratio was selected to be 1:1. The degree of hydration was determined by gravimetry. The distribution among water states was determined from Gaussian deconvolution of the DSC thermograms and use of ΔHf(T) for T