Copolymers of poly(ethylene glycol) methyl ether methacrylates (MW ≈ 300 and 1100) and poly(ethylene glycol) acrylate (MW ≈ 375) with N-acryloxysuccinimide and pentafluorophenyl methacrylate were synthesized by free radical copolymerization in dioxane (80 °C) or THF (60 °C) using azobisisobutyronitrile as initiator. Converting the N-acryloxysuccinimide or pentafluorophenyl methacrylate repeating units with cystamine followed by TCEP·HCl treatment at pH < 7, water soluble, functional copolymers with thiol groups in the side chains were obtained. Reversibly and irreversibly cross-linked gels were prepared by oxidation of the thiol groups to disulfide bonds using H₂O₂ or by reacting the precursor copolymers with ethylene bisacrylate or poly(ethylene glycol) bisacrylate, via Michael-type addition reaction. The obtained gels were compared with regards to their chemical composition and their ability to absorb water by determination of the equilibrium water content of each gel viathermogravimetric analysis.