Preparation And Research On Properties Of Electro-responsive Smart Hydrogel

The research and application of smart materials that respond to external signals has attracted much attention in the research of new materials.Among the smart materials that can change structural,Physical or chemical properties with the environment,Polymer hydrogels are flexible,light weight,the characteristics of biocompatibility are extremely important in some application fields.This article is mainly based on the preparation of ionic Polymer hydrogel modified to prepare composite materials.Ionic hydrogel is an electrical stimulus-responsive hydrogel.It has a hydrophilic three-dimensional Polymer network structure and can absorb water and swell in water.Or dehydration shrinkage,which results in a braking effect of bending to the Positive or negative electrode due to the volume change in the electric field of the directional movement of the ions.However,at Present,the material is not ideal in mechanical properties and response speed,which limits further Practical applications of the electro-responsive hydrogel.Here,the methods of nanofiber doping and conductive Polymer doping and constructing the framework,respectively,can change the internal structure of the gel and increase the ion transmission efficiency,thereby improving the overall mechanical and electrical response Performance of the material.Firstly,nanocomposite hydrogels were introduced based on the copolymer composite hydrogel obtained by radical Polymerization of two monomers,acrylamide(AAm)and2-acrylamido-2-methyl Pro Panesulfonic acid(AMPS).Kevlar fibers are dissolved at room temperature using KOH / DMSO system to obtain aramid nanofibers,which interact with water under high-speed shear emulsification to obtain hydrophilic high-Performance aramid nanofiber fluids(ANFs).On this basis,the modified aramid nanofiber solution(HANF)was obtained by acid-solvent method of aramid nanofibers.After the introduction of these two types of aramid nanofibers,due to the good flexibility of Kevlar fibers and The mechanical properties have greatly improved the shortcomings of low tensile strength and Poor flexibility of P(AMPS-co-AAm).The doping effect of ANFs is more Prominent than HANF,and there is one less Process,especially the doping amount of ANFs is only When the hydrogel dry sample is 1wt%,it is tested under the wet weight dry weight ratio(W / D)of 125% after absorbing water.The average tensile strength can reach 1.18 MPa and the elongation at break is 425%,which is better than that of the blank sample.It has been improved dozens of times.When the doping ratio is increased to 3wt%,the tensile strength of the sample reaches 2MPa,and after multiple tensile deformation tests,it can still be maintained at 1MPa.Secondly,in order to further enhance the electrical properties of Polymer hydrogel materials,multi-walled carbon nanotubes(MWCNTs)were introduced on the basis of ANF /P(AAm-AMPS)to study the ratio of nanofibers and MWCNTs to the mechanical and electrical properties of materials Influence,clarify the optimal formula;then load noble metal atoms into the hydrogel by electroless Plating method to prepare metal-doped nanofiber composite hydrogel materials,and optimize the Process conditions through the study of conductivity and electrical response Performance.Data analysis shows that when both ANFs and MWCNTs are doped at 1wt%,a relatively good balance can be achieved between mechanical properties and electrical stimulus response Performance;as the filler continues to increase,the mechanical Property improvement tends to be gentle.The electrical stimulus response Performance first improved and then decreased,and the response amplitude also began to decrease.After electroless Plating,the conductivity of the hydrogel material can be improved from 1E-5 to 1E-4—1E-2 compared with the blank sample in the water-absorbing state,but the improvement in response to electrical stimulation is limited.Finally,in order to achieve the simultaneous enhancement of the hydrogel’s mechanical properties and electrical stimulus response properties,we thought of using an aerogel material with good electrical conductivity as the skeleton.Here,graphite flakes are used as raw materials to react to Produce graphene oxide(GO),and then the graphene oxide solution is reduced to graphene hydrogel(GH).The monomer is Polymerized on the graphene aerogel after freeze-drying to form a composite Gel;the second method is to mix the Polyvinyl alcohol(PVA)and GO to freeze-dry into an aerogel,then load the monomers,synthesize the gel,and finally absorb the ascorbic acid(LAA)reducing agent liquid to reduce it to obtain a composite gel.Before comparison,the mechanical properties of hydrogel materials have been greatly improved,the average tensile strength has reached 0.7 MPa,and the electrical stimulus response Performance has decreased due to the structure of the material.