A Simple Contact Mechanics Model for Highly Strained Aqueous Surface Gels

Abstract Background Soft, biological, and bio-inspired materials are often compositionally heterogeneous structurally anisotropic, they frequently feature graded or layered organizations. This design complexity enables exceptional ranges in properties performance yet complicates a fundamental understanding of the contact mechanics. Recent studies soft gel layers have relied on Hertzian Winkler foundation (“bed-of-springs”) models to characterize mechanics but found neither satisfactory. Objective The not fully understood. aim this work is develop simple model tailored for compositionally-graded with surface under high strains deformations. Methods Concepts from polymer physics, fluid draining, combined which relates applied normal force probe radius curvature, elastic modulus, thickness subjected strains. Results was evaluated two examples spanning multiple length-scales, including commercially available lenses stratified hydrogels. captures nonlinear highly strained aqueous more closely than either Hertz theory while simultaneously enabling prediction layer. Conclusion These results indicate that can adequately layers.