Preparation And Properties Of Polymer Hydrogels Based On Gelatin-Acrylic Acid

Hydrogels are a family of polymer networks containing hydrophilic and hydrophobic groups.They have a soft texture,can maintain a certain shape,and can absorb a large amount of water.Their expansion behavior under external stimuli has broad application prospects.In this paper,two kinds of polymer hydrogels were designed and prepared:1)Based on gelatin(GEL),thioctic acid(TA),acrylic acid(AA)and other raw materials,a new conductive GEL/PTA/AA hydrogel with good mechanical properties,strong adhesion and fast self-healing ability was designed.Gelatin and poly(thioctic acid)double network structure can prolong the service life of hydrogels by using non covalent bond interaction(e.g.,metal coordination interaction,hydrogen bond and supramolecular interaction)or dynamic covalent bond(e.g.,disulfide bond and borate bond).Based on ring opening polymerization(ROP),lipoic acid and non-covalent bond were reversibly crosslinked to prepare polymer hydrogels with high repair efficiency.Their excellent self-healing properties,tensile properties,and low temperature resistance solved the problems of low repair efficiency and speed of flexible self-healing hydrogels,low tensile properties of conductive self-healing gel,and low temperature freezing,respectively.2)A multifunctional polymer hydrogel with toughness,mechanical stability,self-healing and high conductivity based on gelatin,acrylic acid and liquid metal(LM)was prepared.Gallium indium alloy(EGa In)is a widely used liquid metal.The research of LM hydrogel sensor has attracted extensive attention of scientists.As a kind of soft filler with high conductivity,liquid metal can solve the problem of mismatch between hydrogel and sensor with low conductivity and poor sensitivity.The addition of sodium hydroxide reacts with acrylic acid to produce sodium acrylate,resulting in a copolymer of acrylic acid and sodium acrylate.The prepared gel shows high transparency and good self-healing ability,which can achieve the effect of remodeling.The toughness of the hydrogel can support itself to lift and pull heavy objects.It can adhere to various substrates in the air and underwater,and will not cause allergic reactions on the skin.It can monitor various movements of the human body,including wrists,fingers,knees and pulse.