Design And Mechanism Of Self-healing Hydrogel With Fluorescence Response And Stress Monitoring

Bio-inspired devices and materials have developed rapidly in recent decades.By studying the natural rules,scientists have made breakthrough research in many fields including structural science and mechanical engineering systems.In the direction of material research and development,the ideas have come out as endless stream and a lot of higher requirements have been put up for the intersection of multiple systems.As one of the research hotspots of next generation materials,hydrogel has long-term prospects in the field of bioengineering,and further showed its potential application value in the frontier fields including seawater purification and energy storage.Bionic surfaces that enable self-healing and remote sensing have an urgent needing in micro-crack monitoring,smart wearable devices,and marine anti-corrosion.In this project,we have prepared a multi-network hydrogel doped with fluorescent quantum dots,and further complete the specific research contents as follow:（1）Self-healing hydrogels composed of polyvinyl alcohol（PVA）,chitosan（Chitosan）,and agarose（Agarose）,which based on multi-hydrogen bond network,using reversible physical cross-linking to achieve self-healing through the ability of glycerol and boric acid.Quantum dots were doped uniformly in the bulk phase in order to achieve photoluminescence effects.The as-prepared quantum dot fluorescent hydrogel not only exhibits excellent toughness and mechanical stability,but also has great self-healing property.This material can realize self-healing in different media（air,water,oil,salt solution）,ambient temperature（from-10 to 50°C）,acidic or alkaline solution（p H:from 1 to 14）without any external stimuli.In addition,the hydrogel also exhibits a pressure reshaping effect which means the damaged hydrogel can be reshaped into a new one at room temperature without any cracks or previous damage and keep its performance stable.（2）Based on the fluorescence spectrometer system,the relationship between the fluorescence intensity and stress state of the fluorescent hydrogel as well as the self-healing process were studied.It was interesting that the fluorescence effect of the hydrogel was correlated with the surface stress,and the self-healing time had a good linear relationship with the fluorescence intensity as the hydrogel self-healing process progressed.Therefore,by detecting the fluorescence intensity of the hydrogel,it is possible to remotely detect the stress state of the hydrogel regardless of the material property of contact surface,which allowing the resulting measurement to be more accurate.The material also has good biocompatibility.（3）Designed and prepared a pressure detector which can be applied underwater,using the correlation between the fluorescence intensity of the composite hydrogel and the pressure on the surface of the material.The device can detect the environmental pressure,with stable fluorescence intensity in solution containing Fe³⁺,Cu²⁺and p H from 1 to 14.Further combining the gecko-like structure,it can obtain repeated adhesion and adapt to various surfaces.It is expected to be used in underwater engineering and liquid pipeline transportation.