Ultra‐stretchable Transparent Hydrogels with Low Hydrophobic and Amphiphilic Monomers Using Asymmetric Crosslinker to Give Low Mechanical Hysteresis

Exploring a reasonable network design to develop highly stretchable hydrogels with over 1,000% extension is still a big challenge in the field of hydrogel chemistry and materials. Micellar copolymerization with hydrophobic monomers and surfactants/proteins is a well‐studied approach to provide stretchable hydrogels with hydrophobic association domains as sacrificial bonds when subjected to large deformation, but some limitations, such as dose increase of such monomers and surfactant‐free synthesis have not yet been well considered. In this study, we demonstrate a simple but powerful approach to produce transparent, ultra‐stretchable hydrogels expressing more than 3,000% elongation by surfactant‐free copolymerization of low hydrophobic monomer and amphiphilic monomer. We believe that this result offers wider availability of low hydrophobic groups in various water‐containing polymer materials, including gels, micelles, etc.