【软物质科学系列报告12】Prof. Jiaxi Cui: Multifunctional gel materials made of dynamic polymers
报告摘要：
Gels are materials that consist of crosslinked 3D network structures dispersed in liquid. They display a number of promising properties, such as the ability to load drug, biocompatibility and environmental friendliness, responsiveness to external stimuli, adhesion, anti-biofouling and so on. However, traditional gel materials are composed of inert polymer network structures which can’t regulate themselves to adapt environment change such that limit their application in many areas. In this presentation, I would like to introduce how we utilize dynamic polymer systems to create novel gel materials with self-regulated release, extreme stretchability, self-healing ability, switchable wettability, and gating penetrability. At first, we used the copolymer of PDMS and urea to fabricate supramolecular polymer gel to store silicone oil by taking advantage of H-bonding crosslinks. We demonstrate that dynamic liquid exchange between the compartments, matrix and surface layer allows repeated, responsive self-lubrication of the surface and cooperative healing of the matrix. Depletion of the surface liquid or local material damage induces secretion of the stored liquid via a dynamic feedback between polymer crosslinking, droplet shrinkage and liquid transport that can be read out through changes in the system’s optical transparency. On the other hand, we developed a hierarchical system of dynamic crosslinks that includes encapsulation, hydrophobic association, and multiple hydrogen bonds to prepare hydrogel. This system of crosslinks allows the hydrogels to stretch up to 100 times their initial length and to completely self-heal within 30 seconds without external energy input. More than dynamic polymer networks, we also created dynamic liquids that display lower critical solution temperature (LCST) in water and used them to prepare dynamic “gel-like” structure. This structure not only exhibit a thermos-switchable wettability, but also thermos-switchable optical properties and water penetration.