Research On The Mechanism Of Elastic Modulus Affecting Self-Healing Of Hydrogel

Intrinsic polymer hydrogel self-healing materials have the advantages of solid designability and easy control and have been widely used in emerging materials such as flexible devices,biomedicine,and soft robots.However,the gel material has many chemical components,multiple covalent/non-covalent effects coexist,and the system is complex,so its modeling research and repair mechanism interpretation is challenging.To clarify the interface self-healing mechanism of gel materials and promote the development of intrinsic polymer self-healing materials,this paper is based on the self-healing gel driven by host-guest recognition.It constructs a certain number of self-healing functional groups and dynamic network density.The"dual network" repair model is the "self-healing network" with reversible molecular recognition and the "binding network" with adjustable cross-linking density.The change in the density of the binding network is used to adjust the molecular activity of the repair network,combined with fluorescent labeling and The characterization of interface force explains the influence mechanism of elastic modulus on gel network diffusion and repair performance,which is expected to provide theoretical.support for the preparation of high-performance self-healing gel materials.The main work content is as follows:(1)We designed and prepared a host-guest gel based onβ-cyclodextrin/adamantane recognition as a "self-healing network".Furthermore,we prepared the polyhydroxyethyl acrylate(pHEA)gel in this network as a "binding network",and constructed a self-healing hydrogel model with double networks with continuously adjustable elastic modulus.Then,we label the skeletons of the "self-healing network" and "bound network" by using the fluorescent molecules,respectively.We obtained the polymer segment’s motion law dependent on the self-healing interface’s elastic modulus and explored a self-healing gel network diffusion visual research method.(2)We systematically studied the mechanical properties,interface bonding strength,and self-healing performance of the double-network gel.We found that when the elastic modulus of the double-network gel decreased from(108 ±3.00 kPa)to(41±2.26 kPa),the corresponding interface effect of weak "bound network"(1±0.10 kN/m2)is an order of magnitude higher than that of the firm "binding network"(0.1±0.02 kN/m2),and the self-healing efficiency increased from 17%to 72%,which is consistent with the visualization results.Finally,we proposed the dependence between the self-healing properties and the elastic modulus of the gel.