Studies On The Preparation And Performance Of Superhydrophobic Flexible Pressure Sensors By Electric Field Synergistic Plasma

Wearable pressure sensors have received a lot of attention for their potential applications in medical diagnosis and human-computer interaction.Currently,most materials commonly used for flexible wearable pressure sensors are conductive polymers or flexible fabrics,which are susceptible to environmental factors such as moisture and dirt,resulting in severe signal distortion;the commonly used graphene flexible pressure sensors are not responsive enough to the external force applied in the vertical direction.Based on the above problems,this paper uses plasma polymerization cross-linking to immobilize graphene sheets and combines electric field directional induction to construct a conductive coating with a three-dimensional spatial network structure and increase structural deformation,so as to obtain a superhydrophobic flexible pressure sensor with good stability and high sensitivity,as follows:First,the effects of parameters such as plasma discharge time,PDMS concentration,Ti O₂concentration,electric field strength and electric field direction on the superhydrophobic properties as well as the conductive properties of the prepared coated fabrics were explored,and the performance tests of the conductive hydrophobic fabrics prepared under different conditions were carried out to obtain the optimal experimental conditions affecting their performance.The results show that the optimal process for the preparation of superhydrophobic conductive polyester fabric by plasma is:gas pressure of 50 Pa,discharge power of 50 W,discharge time of15 s,optimal concentration of 30 g/L for PDMS and 0.5 g/L for Ti O₂,and the contact angle of the fabric can reach a maximum of 160.52°and a minimum rolling angle of 7°.And the coating still has good mechanical stability after 600 abrasion cycles or after 200 washing cycles.After adding graphene to the coating,good superhydrophobicity was maintained even after four dip plasma treatments.And single-layer fabric conductivity is good,the current voltage curve through the origin,in line with Ohm’s law,conductive coating fabric after 10 rubbing cycle sensing effect can still reach more than 90%,with good mechanical wear and tear effect.Secondly,the effect of electric field induced graphene sheets to construct a three-dimensional spatial structure on the sensor performance was investigated.The effects of electric field strength and direction of action were investigated.Scanning electron microscopy（SEM）before and after electric field induction showed that the graphene sheet was deflected directionally by the electric field,the conductive coating constructed a three-dimensional network structure,and the pressure sensor after electric field induction had higher sensitivity in the small pressure range.And the response time and response time of the fabric sensor were reduced to 100 ms,and it showed good stability under 160 s continuous cycle test.Finally,sensing tests conducted from the surface of human body and underwater environment show that the pressure sensor after electric field induction can achieve stable and sensitive response in different environments.In addition,the superhydrophobic conductive fabric prepared by the plasma method has good environmental weather resistance.The hydrophobicity and conductivity of the fabric in different liquid environments were compared,and the results showed that the superhydrophobic conductive fabric can still maintain a high contact angle and stable conductivity,which indicates that the superhydrophobic conductive fabric is expected to be applied to underwater monitoring and has broad application prospects in the field of smart wearable electronics.