Multiresponsive Hydrogels Formed by Interpenetrated Self-Assembled Polymer Networks

It is shown how interpenetrated polymer networks can be formed by self-assembly in water of two different amphiphilic triblock copolymers, which preserve and combine the properties and stimuli-responsiveness of each polymer. Aqueous solutions of a pH and a UV-sensitive triblock copolymer spontaneously formed a self-assembled interpenetrated network when mixed. The polymers were based on poly(acrylic acid) and poly(ethylene oxide), respectively, and had different hydrophobic end blocks. The structure of the mixed networks was studied with light scattering and the dynamic mechanical properties were studied by oscillatory shear measurements. Synergy led to reduction of the percolation concentration of the individual polymer networks within the interpenetrated network.