The Structure Design,Preparation,and Performance Study Of Flexible Mechanical Sensor

With the rapid development of electronic products,wearable electronic devices have attracted considerable attention.Among them,flexible mechanical sensors play an important role in wearable electronics,health monitoring system,intelligent robot and other fields due to the characteristics of extension,bending and even folding.This research focuses on the structural design,preparation and application of high-performance flexible mechanical sensors.This paper mainly includes the following two parts:?1?Two-sided topological architecture design and fabrication for high ultrasensitive flexible strain sensor.Sensitivity is a key target of flexible strain sensor.In order to improve the performance,this paper proposes a two-sided topological architecture design method of polymer substrate from Poisson's ratio,stress distribution and other aspects,and realizing the simulation and optimization of the mechanical distribution of devices under different substrate structures combining the finite element method?FEA?.Based on the simulation results,the flexible strain sensor with different substrate architecture was fabricated,which used PEI/rGO as sensing layer.Experimental results show that the sensitivity of the device is 22 times higher than that of the nonstructured device,which can detect weak signals such as hair slip and feather sweep.At the same time,the theoretical and experimental results show that the increasing sensitivity is mainly due to the synergistic effect of the local strain distribution enhanced by the structure of sensitive layer,as well as the strain concentration distribution generated by the auxetic structure and the decrease of Poisson's ratio of the device.In addition,due to the negative Poisson's ratio,the flexible strain sensor has a strong impact resistance.?2?Design,preparation and application of multifunctional E-textile.In recent years,the mechanical sensors based on fabric sensors are softness,air permeability,skin friendly,which become the focus of people's attention.Multifunction is an important development trend of fabric mechanical sensors,which is also an important opportunity for the future development of intelligent wearable systems.In this paper,a flexible pressure sensing fabric based on the silver nanowire?AgNWs?conductive network is prepared,which integrates the characteristics of thermal insulation and heating into the sensing fabric effectively and energy-saving,so that it has four functions of pressure sensing,infrared thermal insulation,Joule heating and PM particle filtering at the same time.In terms of sensing function,this paper puts forward the multi-scale contact mechanism model of fiber/yarn/abric,realizing the preparation of flexible pressure sensing fabric with high sensitivity and wide range by combining the design of fabric mesh partition and three-dimensional support structure;in terms of thermal insulation,the preparation of fabrics with different metal network density is controllable,which could effectively reflect the infrared radiation of 8-14?m of human body.Furthermore,two-way thermal insulation performance from-40°C to 80°C was achieved by combining the three-dimensional support structure Designed;in terms of heating performance,excellent Joule heat effect and stability are obtained through optimization of fabric sensitive layer;PM_2.5 filtration efficiency is more than 98%by using dense structure of metal network and strong surface adsorption capacity.The multifunctional flexible pressure sensing fabric prepared in this paper is expected to be used in intelligent clothing,human monitoring,medical care and other fields.