Fabrication And Mechanical Analysis Of Hydrogel Composites And Their Application

Hydrogels,as a kind of polymer materials composed of crosslinked macromolecules and water,have the properties of high water content,softness and good biocompatibility,which making them promising candidates in various applications such as tissue engineering,drug delivery,biosensors and artificial organs etc.For most hydrogels,however,poor mechanical properties limit their further implementation where mechanical performance becomes a critical concern.Despite the considerable progress in developing tough hydrogels,there is still a requirement to prepare high-performance hydrogels using simple strategies.Double-network(DN)hydrogels,as a kind of special tough hydrogels,have been widely studied by researchers.However,there are few researches on designing macro-DN hydrogels or composites according to the DN toughening mechanism.The macro-DN material has a layer of macroscopic reinforcing network,which follows the mechanism for dissipating mechanical energy in DN hydrogels,so this composite material can not only have excellent mechanical properties,but also show the special properties of the macroscopic network.Moreover,for a special kind of hydrogels,conductive hydrogels possess great potential for the development of soft smart devices due to the good combination of electrical and mechanical properties.To prevent the loss of moisture and short circuiting,a dielectric scarfskin is typically required for these hydrogel devices.While the stretchability of traditional dielectric material is usually much lower than the hydrogel.Therefore,it is of great significance to explore the ultra-stretchable hydrogel composites to accommodate hostile environments for the intelligent sensing applications.According to the above problems in hydrogels,the main research work is as follows:First,a sponge-reinforced hydrogel composite is synthesized by combining poly(acrylamide)(PAAm)hydrogel and polyurethane(PU)sponge.Uniaxial compressive testing of the hydrogel composites reveals that both the compressive modulus and the strength(at the compressive strain of 75%)of the hydrogel composites are much higher than those of the PAAm hydrogel or sponge.In order to predict the compressive modulus of the hydrogel composite,we develop a theoretical model that is validated by experiments and numerical simulations.Then,we explore the preparation process of macro-DN hydrogels,and improve the manufacturing method of low-melting point alloy skeleton with specific shapes,and summarize and optimize the preparation criteria of macro-DN composites.Finally,doping ion compounds,we synthesize the conductive hydrogels,and the conductive hydrogel fibers are prepared by template method,and coated with a dielectric layer,an ultra-stretchable conductive hydrogel composite fiber was prepared which demonstrating sensing properties and scalability.