Cytoskeleton-Inspired Artificial Protein Design to Enhance Polymer Network Elasticity

Reducing topological network defects to enhance elasticity in polymeric materials remains a grand challenge. Efforts to control network topology, primarily focused on cross-linking junctions, continue to underperform compared to theoretical estimations from idealized networks using affine and phantom network theories. Here, artificial protein technology was adapted for the design of polymer-network hydrogels with precisely defined coil-like and rod-like strands to observe the impact of strand rigidity on the mechanical properties of polymeric materials. Cytoskeleton-inspired polymer-network hydrogels incorporated with rod-like protein strands nearly tripled the gel shear elastic modulus and relaxation time compared to coil-like protein strands, indicating an enhanced effective cross-linking density. Furthermore, asymmetric rod-coil protein designs in network strands with an optimal rod/coil ratio improved the hydrogel relaxation time, enhancing the stability of physical macromolecular associations by modulating the cross-linker mobility. The careful design of strand rigidity presents a new direction to reduce topological defects for optimizing polymeric materials.