Preparation Of Biochar-based Flexible Piezoresistive Sensor Material And Its Performance

In recent years,flexible electronic devices,wearable devices,health care and other fields have been rapidly developed,and electronic devices based on flexible piezoresistive sensing devices have become a research hotspot in the sensing field.Biomass charcoal material has the characteristics of stable performance,good electrical conductivity,high cost performance and friendly to the environment,which makes it an ideal material for flexible piezoresistive sensors.In this paper,using the residue of Eucommia ulmoides as the raw material,the conductive biochares were prepared by high temperature carbonization,which were composite with polydimethylsiloxane(CEUR/PDMS)to prepare the composite pressure sensing materials.A flexible composite pressure sensing material based on biochar was prepared by using carbonized eucommia ulmoides residue(CEUR)as conductive filler,PU as conductive particle dispersant and PAM hydrogel as supporting matrix.The practical application effect of the material is discussed,and the main research conclusions are as follows:(1)The composite pressure sensing material of carbonized eucommia ulmoides residue(CEUR)/polydimethylsiloxane(PDMS)was prepared using the carbonized eucommia ulmoides residue(CEUR)as conductive filler and polydimethylsiloxane(PDMS)as flexible polymer substrate.When the content of CEUR was 44.4%,The conductivity of Ceur /PDMS composites is 0.12S·m-1,the sensitivity is up to 142.1 kpa-1 in the range of 0-2k Pa,and the response time to stress is about 0.7 S.The CEUR/PDMS flexible materials have stable responses to pressure signals at different frequencies.(2)The composite flexible pressure sensing material of CEUR/PAM/PU sponge was prepared by combining the carbonized Eucommia ulmoides residue(CEUR)as conductive filler and PU as dispersive template.When the mass fraction of CEUR accounted for 9.1% of PAM,the response effect was the best,and the maximum sensitivity GF reached 20.04.(3)The composite flexible pressure sensing material prepared has excellent stability and durability,can sense small stress changes in human activities,and has rapid response,low hysteresis and excellent stability.The composite flexible pressure-sensitive sensing material prepared in this study has a broad application prospect in the fields of wearable devices and robot electronic skin,and provides a new idea for the development of sensing materials with low cost and simple preparation process..