Construction Of Hybrid Conductive Network Based On Carbon Nanotubes And Sensing Performance Of Strain Sensor

Recently,aligned with the rapid development of flexible and wearable electronics,strain sensors comprising elastic polymeric matrices and conductive fillers are widely applied in diverse areas including electronic skin,human movement and health monitoring,fitness tracking and human-manchine interaction.High sensitivity and large sensing range are hardly achieved in conventional sensors simultaneously,which ressitricted their applications.One-dimentional elastic carbon nanotubes(1D CNTs)are ideal conductive building blocks due to high electrical conductiveity,high aspect ratio and scalabe synthesis.In this work,biomemitic strategies are employed to construct high-performance strain sensors by preparing novel CNT-based building blocks and hybrid conductive networks to monitor human motions and health.(1)Inspired by the geometries of spider web and spider slit organ,a versatile strain-sensing platform with metal–organic framework-derived porous carbon-welding carbon nanotube(MPC–w–CNT)percolation networks is reported by soldering the crossing-points of CNTs using MPCs followed by embedding in poly(styrene-block-butadiene-block-styrene)(SBS),which can enhance effective transfer of electrons and load among adjacent CNTs as well as avoid the interfacial slippage during cyclic stretching-releasing.The junction bonding could enable the bioinspired strain sensors to detect small and large deformations with a low limit of detection(0.0085% strain),a large sensing region(～640% strain),high sensitivity(～7378.26),and short response time(～122.5 ms),along with excellent reliability(～1,000 stretching-releasing cycles),which allow the bioinspired sensors to detect the full range of human movements.The advantages of these sensing properties are reflected in the welding design of the multilayer MPC-w-CNTs network combined with SBS.More importantly the unique junction bonding strategy can be applied in other nanomaterial systems to develop stretchable electronics.(2)Inspired by the biologically gradient structures,we rationally designed a high-performance strain sensor exhibiting gradient distribution of conductive building blocks.First,ZIF-8and ZIF-8-w-CNTs with controllable structures are successfully synthesized,which are subsequently carbonized and washed to obtain highly conductive porous carbon polyhedrons(PCP)and PCP-w-CNTs.Three layers of PCP/PCP@CNTs/CNTs conductive network with gradient structures are constructedby vacuum-assisted filtration,which are embedded in SBS matrix.The aspreapred strain sensor possesses a high sensitivity(～5797.83),wide sensing range(strain660%),low detection limit(0.01% strain)and excellent stability(1000 tensile cycles).This excellent sensing performance can enable strain sensor to detect large movements of the human body(fingers,elbows and knees),and tiny physiological movements(human pulse).Additionally,the composite film can respond to temperature variations and liquid infiltration with accurate and stable signal outputs...