Preparation And Performance Study Of Multifunctional Conductive Composite Materials

Flexible sensors have broad application prospects in the fields of soft robots,health monitoring,electronic skin,human-computer interfaces,and have received widespread attention in recent years.At present,the research on flexible sensors is still in its infancy.The preparation of flexible sensors with excellent comprehensive performance remains a challenge.In particular,flexible sensor with multifunction and strong environmental adaptability is desired for modern flexible wearable devices.In this thesis,two commercialelastic polymers were selected as flexible substrates,and two multifunctional conductive composites were prepared by simple surface coating method.The multifunctional integrated conductive composites solved the problems of moisture absorption and surface icing of flexible materials,making the material highly adaptable and durable in complex environments.Piezoresistive sensors and strain sensors with excellent comprehensive performance were prepared based on two materials.The morphology,superhydrophobicity,thermal performance,and application of the materials were studied and investigated,and the influence of conductive network systems on sensing performance was systematically studied.Specifically,the work in this thesis includes the following two parts:（1）Through sugar template method and following immersion assisted reduction,polydimethylsiloxane（PDMS）sponge embedded with carbonyl iron（CI）was successfully anchored with silver nanoparticles（Ag NPs）binded with polystyrene-block-poly（ethylene-co-butylene）-block-polystyrene（SEBS）.A multifunctional sponge type conductive composites was prepared.Conductive sponge had excellent superhydrophobic properties（water contact angle=153°）,efficient Joule heating（1.6 V,101℃）and photothermal conversion capabilities（250 m W/cm²,102℃）.The conductive sponge pressure sensor had excellent piezoresistive properties,including high sensitivity(3.8k Pa^-1),wide detection range（160 k Pa）and robust stability when subjected to 1000compression-release cycles,which could be further utilized to accurately and reliably monitor the changing biophysical signals.Besides,conductive sponge had high oil/water separation efficiency as well as magnetically guided waste oil adsorption ability.（2）A multifunctional conductive fabric with double conductive network was successfully prepared by assembling conductive Ag NPs and carbon nanotubes（CNTs）layer by layer on the surface of the elastic PP nonwoven fabric.SEBS added as a binder promoted strong interaction between conductive fillers and the fabric.Benefiting from the synergistic interaction between conductive fillers of different dimensions,the strain sensor based on the conductive fabric has high sensitivity（GF up to 8064）,wide detection range（0-200%）,and excellent stability and durability（more than 10000 stretch-release cycles）.Besides,the prepared conductive fabric demonstrated excellent superhydrophobic property（water contact angle=154°）,the excellent durability and stability of the superhydrophobic surface ensured the stability of the fabric sensor under harsh environment.At the same time,the fabric also displayed excellent photothermal conversion performance（0.2 W/cm²,90℃）.The multifunctional integrated conductive fabric shows excellent sensing performance and environmental applicability,indicating its wide application potential in motion monitoring,self-cleaning,biomedicine and other fields.