Functional Molecular Regulation Of Hydrogel Interface Adhesion And Its Application

Hydrogel is a kind of biological tissue-like material formed by three-dimensional crosslinked hydrophilic polymers with water as dispersion medium.The loose space network skeleton structure of hydrogel makes it have excellent modifiability,endowing hydrogel with adjustable physical and chemical properties.With the development of science and technology,hydrogels are widely used in biomedicine,adhesives,coating materials and flexible electronics due to their excellent properties.Therefore,the application and development of hydrogel put forward higher requirements for its corresponding properties to meet its practical application scenarios.Among the most important properties are strong adhesion to various components or skin tissues.In recent years,substantial progress has been made in hydrogel adhesion and functional design.However,there are still some critical challenges,including the balance of toughness and viscosity of hydrogels,the interface matching problem during stretching of differentiated functional layers,and the general long-term stability of hydrogels among various substrate materials.The combination strategy of interface and easy operation.To solve the above issues,this work proposed a strategy of functional molecules to construct hydrogel adhesion,and developed a gradient adhesive tough hydrogel induced by unilateral coordination of functional molecules and a hydrogel interface adhesion strategy based on polyphenol molecules control.Through the design of hydrogel gradient structure,the gradient adhesive hydrogel was successfully endowed with different adhesion on different surfaces,which effectively realized the unity of toughness and interface adhesion of hydrogel.It was applied to wearable strain sensors to realize the monitoring and recognition of human motion signals.Using the chemical properties of polyphenols,an interface adhesion strategy for simple operation of hydrogels between substrate materials was developed.The specific research work is divided into the following research contents:An adhesive layer was constructed on the surface of tough polyacrylamide-calcium alginate(PAAm-SA-Ca²⁺)hydrogel by unilateral coordination-induced diffusion of functional molecule（EDTA）in this work.Form a gradient structure from viscous surface to ductile surface.The diffusion kinetics of functional molecules in hydrogels was visualized,and the diffusion law that diffusion time was positively correlated with the square of distance was obtained.Based on the autologous adhesive hydrogels obtained above,the adhesion of gradient viscous hydrogels constructed by functional molecules to different material surfaces was investigated,and their adhesion and mechanical properties were quantitatively analyzed.It provides theoretical and practical basis for the practical application of functional molecules to construct hydrogel adhesion.Finally,the prepared gradient tough hydrogel was used for wearable strain sensor,which showed good linearity and sensitivity in a certain range.Can realize the capture of human motion and motion monitoring.Inspired by the adhesion mechanism of mussels,a novel hydrogel adhesion strategy of"interface molecular lock"（IML）was proposed by using polyphenol molecules to assist hydrogel interfacial adhesion.The effect of different molecules on the adhesion of the hydrogel interface was studied,and the structure-activity relationship between the interface molecular locking mechanism and the hydrogel structure was investigated.The universal applicability of interface adhesion is also verified.Based on this,the properties of polyphenol molecules were used to enhance the interfacial adhesion step by step.It provides a new simple and feasible new scheme for hydrogel adhesion,which is conducive to the expansion of hydrogel applications.