Considering the large number of applications for hydrogels, a better understanding of the relation between molecular structure and mechanical properties for well-defined hydrogel is essential. A new library has been compiled of poly(ethylene glycol) polymers (PEG) of different length end functionalized with diallyl, dithiol, and dimethacrylate, and crosslinked with complementary trifunctional crosslinkers. In this study, the hydrogels were initially analyzed by FT-Raman and NMR to study the conversion ratio of the functional groups. The effects of solvent type, solid content concentration, curing time and length of the PEG chains on the final leaching, swelling and tensile properties of the hydrogels were studied. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: PolymChem 49: 4044-4054, 2011