ABSTRACT: Composed mostly of solvent molecules and a loosely crosslinked polymer network, a polymeric gel appears and feels like a liquid solution. It is natural to wonder whether the properties of a liquid-like gel are fully determined by its composition, or will they be affected by synthesis conditions and processes like conventional solids? Through carefully planned experiments, the mechanical properties of a set of compositionally identical gels prepared through different processes are tested systematically. Strong dependences of the mechanical properties on the synthesis conditions were identified, and the results well captured by a set of scaling laws, which can be derived from the theory of semi-dilute solutions, in conjunction with three assumptions on the underlying network topologies and structural evolution. In addition, further study on the fracture property of these compositionally identical gels also suggests intriguing relations with the synthesis processes, which can also be rationalized through with the network structures as results of the processes. These findings are helpful to the understanding of the process-property relations of polymeric materials, and to the design and synthesis of hydrogels of extraordinary performance.

BIOSKETCH: Wei Hong is currently Professor and Associate Chair of the Department of Mechanics and Aerospace Engineering at Southern University of Science and Technology (SUSTech). Wei got both B.S. and M.S. degrees from Tsinghua University, and Ph.D. in Engineering Sciences from Harvard University. Before joining SUSTech in 2018, wei worked in the Department of Aerospace Engineering at Iowa State University as Associate Professor. He also held joint appointment from Hokkaido University as Associate Professor and later as Professor. Wei’s research covers areas including solid mechanics, fracture mechanics, microstructure evolution, Multiphysics modeling, and recently focuses on polymer physics, dielectric breakdown, adhesion, active materials and smart structures, and surface instabilities.