Poroelastic material is a two-phase system consisting of a porous solid skeleton filled with liquid. The poroelasticity was originally developed for studying the consolidation of soils. In this study, I explore its applicability on polymeric gels which are composed of cross-linked polymer networks swollen in an aqueous solution. Gels have broad applications in many engineering fields but are difficult to characterize through mechanical tests because of their soft and brittle characters. In this talk, I will show that within the theory of poroelasticity, the force relaxation curves from indentation can be obtained in remarkably simple forms, enabling indentation to be used with ease as a method for determining the elastic constants and diffusivity of gels. Besides material characterization, I also explore the novel applications of poroelastic materials. I will show that the surface topography of a poroelastic material can be continuously tuned from a perfectly smooth one to a rough one due to the liquid’s ability to flow and reconfigure in response to the matrix deformation. In particular, I will demonstrate simultaneous control of the material’s transparency and its ability to continuously manipulate various low-surface tension droplets from free-sliding to pinned. In another example, I will show that the liquid’s ability to flow and reconfigure also provides a unique gating mechanism. The micro pores of a poroelastic membrane can be selectively opened and closed for gas and liquid transport while the liquid layer coating around the pores almost completely prevents fouling inside the pores. These novel properties of poroelastic membranes can benefit many industrial and biomedical applications.

 

Dr. Yuhang Hu is currently an Assistant Professor in Mechanical Science & Engineering at University of Illinois Urbana-Champaign. Before joining UIUC, she was a postdoctoral fellow in the School of Engineering and Applied Sciences at Harvard. She received her bachelor’s degree in Engineering Mechanics at Shanghai Jiao Tong University, China, and master’s degree in Civil and Environmental Engineering at Nanyang Technological University, Singapore. She obtained her Ph.D. in Engineering Sciences at Harvard University. Dr. Hu’s research focuses on the mechanics of soft materials and bioinspired materials. Her study involves both theory and experiments.