Hierarchical, Porous Hydrogels Demonstrating Structurally Dependent Mechanical Properties

Abstract

Abstract While hierarchical ordering is a distinctive feature of natural tissues and is directly responsible for their diverse and unique properties, research efforts to synthesize biomaterials have primarily focused on using molecular-based approaches without considering multiscale structure. Here, we report a bottom-up self-assembly process to produce highly porous hydrogels that resemble natural tissues both structurally and mechanically. Randomly oriented, physically crosslinked nanostructured micelles form the walls of aligned, polymer-rich pore walls that surround water-rich cavities. Extremely soft elastic modulus (< 1 kPa), highly stretchability (greater than 12-times), strain-hardening, and completely reversible deformation result from the hierarchical structure. Independent control of nano and macroscales is realized through the combination of polymer macromolecular parameters and processing conditions, directly impacting the resulting phase behavior. Here, we demonstrate precise control of the material structure and structure orientation over many orders of magnitude (e.g., nm – µm), and reveal how the multiscale structure directly impacts mechanical properties.