Supersoft, Porous Hydrogels with Structure and Properties Reminiscent of Natural Tissue

While hierarchical ordering is a distinctive feature of natural tissues and responsible for many of their unique properties, replicating such structures in synthetic materials is extremely difficult. Here, we combine the nanoscale micelle network formed from the self-assembly of amphiphilic triblock copolymers in water with the porous microstructure formed during solvent exchange to produce biomimetic hydrogels. Initially, the triblock copolymer is dissolved in an organic solvent common for both blocks and injected into water. The simultaneous solvent exchange and micellation of the polymer in water will produce a porous gel, with micelles forming the pore walls. Here, we show that the micellar nanostructure is largely insensitive to processing conditions but varies with polymer size and composition. In contrast, the porous microstructure is heavily dependent on the processing conditions of the polymer. The gels are extremely soft, but surprisingly these materials can stretch to many times their original length, with strain-hardening behaviors at high strain and no hysteresis upon recovery. This research presents an exciting class of new materials, with diverse applications and an opportunity to probe the mechanisms of non-solvent induced self-assembly.