Adhesion Of Hydrogel Materials And Its Application

As one of the most important soft materials,hydrogel materials have a threedimensional(3D)crosslinked network consisting of a hydrophilic polymer and a large amount of water.Since its discovery,hydrogels have attracted much attention due to their unique composition and structural similarity to natural biological soft tissues and their excellent elastic properties.To date,hydrogel materials have been widely used in a variety of applications,such as materials science,electrical engineering,biochemistry,and biomedical fields.For example,they can be used as actuators and sensors for reversible motion and control of soft robots,containers for drug delivery,or as 3D scaffolds for tissue engineering.But hydrogels do not exist alone in many cases,they perform unique and outstanding characteristic through combing with other substance.For instance,the muscle binds to the bones to complete the diverse behavior for daily demands in organism.In recent years,the development of synthetic hydrogel hybrids has been promoted by this biological design.Especially,synthetic hydrogel-polymer hybrids are ubiquitous in a wide range of areas,including soft electronics,artificial axons and implantable devices.However,limited by the rich water content in its 3D network and the water membrane on the surface of substrates,the bonding strength of hydrogelpolymer hybrids is weak,for robust adhesion can never be achieved by attaching water molecules in the hydrogel to the other polymer substrates,which severely hampers the application of the hydrogel.Therefore,how to achieve high-strength adhesion between hydrogel and polymer substrates is the urgent demand to the extensive application of the hydrogel hybrids.In this paper,a suitable monomer was selected as an adhesion layer through bionics and a large number of preliminary experiments.Based on this,a fast and high-strength adhesion of the hydrogel on different substrates was achieved,and its adhesion strength was basically above 1 MPa.In addition to the simple preparation process,the adhesion achieved by this method also has anti-fatigue performance,which guarantees the service life of the hydrogel in practical applications.Based on this,this paper combined a responsive hydrogel with a soft substrate to successfully prepare an intelligent response gripper.By changing the p H of the external environment,self-driven bending and relaxation of the gripper was achieved.It provides a feasible idea for the application of hydrogel in the field of self-driven intelligent soft robot.It was found through experiments that the adhesion of the hydrogel can effectively limit its swelling.By combining the hydrogel with a rigid substrate,on the one hand,the inherent surface morphology of the hydrogel can be maintained,and on the other hand,we have achieved a spontaneous transformation of the surface morphology of the hydrogel from two-dimensional to three-dimensional.