Topoarchitected Polymer Network Hydrogels with High Toughness and Anisotropic Properties

Natural load-bearing tissues such as muscles, tendons, and cartilages exhibit exceptional toughness and anisotropy due to their well-defined ordered composite structure and strong adhesion between the structural components. However, synthesizing bioinspired soft materials with similar structure and properties remains a significant challenge. Here, we design a stripe-patterned topoarchitected polymer network (TPN) by combining interpenetrating polymer networks with a two-phase composite structure. We use a three-step sequential polymerization process along with photolithography to prepare TPN hydrogels, where densely cross-linked hard phase structure is in topological entanglement with a loosely cross-linked soft phase matrix to achieve strong interfacial adhesion. The stripe-patterned TPN hydrogels possess both high toughness and anisotropic mechanical properties. This work provides a general network design strategy for synthetic soft materials analogous to natural load-bearing tissues.