Preparation And Properties Of Ti₃C₂Tx/PDMS Flexible Conductive Composites

MXene is a new type of transition metal carbide or nitride.Its general formula is M_n+1Xn Tx?n=1-3?,where M is an early transition metal,X is C or N,and Tx refers to a surface functional group.The two-dimensional carbide Ti₃C₂Tx belongs to one of the two-dimensional materials MXene,and its unique structure gives the material better physical and electrical properties,allowing it to be better used in the field of composite materials.Flexible conductive composite materials have good flexibility and conductivity,and resistance changes under stress and strain conditions,so they have good applications in wearable devices and flexible electronic screens.In this study,the pure Ti₃C₂Tx was obtained by improving the traditional preparation method of Ti₃C₂Tx,and it was combined with PDMS by blending method,spray printing method and swelling penetration method to prepare Ti₃C₂Tx/PDMS flexible conductive composite material.Ti₃Al C₂ is etched by using the ratio of HCl+Li F,the layer spacing becomes larger after the layering process,and a small amount of single layer or few layers of Ti₃C₂Tx can be obtained.The product maintains single crystal properties and has the same hexagonal lattice as the precursor Ti₃Al C₂.There are C=O,C-O and C-F functional groups on the surface of the etched product.Ti₃C₂Tx prepared by this method has good electrochemical stability,rate and conductivity.The Ti₃C₂Tx/PDMS composite material was prepared by blending method.The more Ti₃C₂Tx doped,the higher the strength of the composite material and the lower the deformation ability,but the electrical properties were not significantly improved.Using spray printing,Ti₃C₂Tx is concentrated on the side of the material,which improves the conductivity of the composite material;the strength of the composite material with different Ti₃C₂Tx incorporation is increased,and the elongation at break is reduced.With the increase of Ti₃C₂Tx content,the mechanical properties of the composite materials did not show regular changes,and the electrical properties of the materials changed slowly.In order to avoid the defects of the above two methods,Ti₃C₂Tx/PDMS flexible conductive composite materials were prepared by swelling infiltration.SEM images showed that Ti₃C₂Tx mostly adhered to the surface layer of PDMS,with less internal penetration,and Ti₃C₂Tx on the surface layer gave the material better conductivity.The tensile test found that the mechanical properties of the composites prepared at different penetration temperatures have not changed much,and are basically similar to pure PDMS.The water bath penetration temperature is 60°C,and the material has the best electrical conductivity.The average tensile strain exceeds 90%and the average relative resistance changes exceed 600%.In summary,the blending method can significantly improve the strength of the composite material,but if the electrical performance is improved,the amount of Ti₃C₂Tx must be increased,so it is not economical.However,the mechanical properties and electrical properties of the composite materials prepared by spray printing are improved,but the materials are unevenly stressed when they are stretched by external forces.The swelling penetration method can make the composite material obtain better conductivity and strain sensitivity by adding a small amount of Ti₃C₂Tx,but the mechanical properties of the material have not changed significantly.This study provides new ideas for the preparation of Ti₃C₂Tx,the preparation and application of Ti₃C₂Tx/PDMS composite materials,and has good application prospects.