Tough and Self-Healing Hydrogels Formed via Hydrophobic Interactions

Large hydrophobic monomers stearyl methacrylate (C18) and dococyl acrylate (C22) could be copolymerized with the hydrophilic monomer acrylamide in a micellar solution of sodium dodecyl sulfate (SDS). This was achieved by the addition of salt (NaCl) into the reaction solution. Salt leads to micellar growth and, hence, solubilization of the hydrophobes within the SDS micelles. The hydrogels thus obtained without a chemical cross-linker exhibit unique properties due to the strong hydrophobic interactions. They can only be dissolved in SDS solutions demonstrating the physical nature of cross-links. Results of dynamic light scattering, rheological and mechanical measurements show that the hydrophobic associations…