Hydrogels are crosslink polymers that are capable of absorbing great amounts of water. They have been studied during the last 50 years, largely due to their hydrophilic character at ambient temperatures, which make them biocompatible and attractive for various biological applications. Nevertheless, in our project, we are interested in their hydrophilic-hydrophobic phase-transition, occurring slightly above room temperature. We investigate the mechanical and optical transformations at this phase transition–namely, their swelling, permeability, and optical transmission modification–as enabling responsive or passive dynamics for future product design.