Preparation And Performance Study Of Functional Nanocomposite Hydrogels

As a three-dimensional soft material,hydrogel has compatibility and adjustable physicochemical properties similar to biological tissues,and has broad application prospects in cell carriers,artificial electronic skins and wearable devices.However,the traditional covalent crosslinking of hydrogels is usually brittle in texture,unable to withstand large deformations,and has a single function,which cannot meet the conditions of hydrogel application.Therefore,it is of great significance to develop a powerful hydrogel with great versatility.In this paper,the PAM/Laponite/IL composite strong hydrogel was prepared by radical polymerization.And based on this,a PAM/Lap-IL/TA ion-conductive viscous hydrogel was prepared by ionic liquid(IL)as a conductive material in collaboration with tannic acid(TA)to explore its feasibility as an artificial skin sensor in the future.The specific work is divided into the following aspects:Firstly,a physicochemical double-crosslinked nanocomposite hydrogel was prepared.Due to the addition of ionic liquids(1-butyl-3-methylimidazolium chloride),Lithium magnesium silicate(Laponite)cannot spontaneously form a highly thixotropic gel in water.The uniformly dispersed Laponite nanosheets act synergistically with the chemical crosslinking center of MBA in the polymer chain segment synergizes to build a hydrogel network structure with strong and tough properties.The tensile strength,tensile strain,and fracture energy of PAM/Laponite/IL nanocomposite hydrogels were as high as 1191KPa,6842%and 26.62MJ/m~3.Based on the structural evolution of Laponite,this paper proposes a mechanism to effectively improve the mechanical properties of hydrogels.This highly flexible nanocomposite hydrogel shows great potential as a load-bearing material.Based on the study in the previous section,taking advantage of the high electrical conductivity and solubility properties of ionic liquids,used ionic liquids and water as mixed solvents to co-dissolve Laponite and tannic acid(TA),which were then introduced into the polymer matrix of polyacrylamide(PAM).Then,the phenolic hydroxyl groups carried by TA generated a large number of hydrogen bonds with Laponite and PAM,and the Laponite nanosheets acted as redox buffers to provide a platform for the oxidation and self-polymerization of TA,and this interaction allowed them to exist as common cross-linking points in the polymer network.Because of this,the mechanical and adhesive properties of the hydrogels were significantly improved,and the obtained PAM/Lap-IL/TA hydrogels exhibited excellent tensile strength(152KPa),super-stretchability(4285%)and high adhesion to biological tissues(153N/m).The conductivity efficiency and sensitivity of the hydrogel showed regular changes according to the increase in IL content,exhibiting excellent conductivity(11.60m S/cm)and strain sensitivity(GF=4.76 at 0～800%strain).The addition of IL further improves the functionality of hydrogels while maintaining toughness.The above research work provides a new idea and theoretical basis for the application of hydrogels in the field of artificial skin sensors.