Preparation Of Carbon Nanomaterial Composite Yarn And Its Application In Flexible Stretch Devices

With the successive evolution of wearable electronic devices,scientific researchers have been attracted to flexible strain electronic devices,which can monitor human movements,perception environmental temperature changes,and store energy characteristics.With the development of flexible materials,carbon nanomaterials and conductive polymers,deformable electronic equipment have great application space in various fields.In the field of flexible medical devices,it can detect weak signals such as pulse;the case in point is wearable devices,it can monitor movement;in the field of soft robot which can give the sense of temperature and pressure;in the field of energy storage,it can sustain and stable work under strain,which is of great significance for the preparation of multi-functional flexible electronic devices.In this dissertation,we discussed three methods of preparing flexible stretchable devices and studied their various properties including mechanical properties,electrical conductivity,strain sensing performance,electrochemical properties and electrothermal performance,and durability.The specific research contents are as follows.The first part of this paper is to prepare carbon nanotubes(CNT)/cotton yarn(CCY)by soaking CNT in cotton roving and spinning on ring spinning frame,and pyrrole is polymerized in situ.Then,CNT/cotton/polypyrrole(PPy)composite yarn(PCCYP)is made by twisting on fancy twister.Next,PCCYP is woven to composite fabric(PCCYP fabric).Finally,PCCYP composite yarn is prepared to flexible supercapacitors.We researched the mechanical,electrical and electrochemical properties of the composite yarn and stable performance under different bending angles.At the same time,the electrothermal properties of the composite fabric,including the effect of heating,Low external voltage(1V,temperature up to 43.5°C)and good cycle stability.These results demonstrate the potential application of composite yarns in wearable flexible devices.In the second part of this paper,the preparation of CNT/cotton spinning as same as the first part.In a word,the cotton roving was dipped into CNT and by ring spinning to obtained CNT/cotton yarns(CCY).then Spandex/CNT/cotton core spun yarn(SCCY)is prepared on fancy twister with spandex filament as core yarn and CCY as decoration yarn,and then the sample were dipped in CNT and pyrrole was polymerized to prepare CNT/cotton core spun yarn PPy/CNT/Spandex/CNT/cotton core spun yarn(PCSCCY)was prepared.Finally,the core spun yarn was assembled into strain sensor and flexible supercapacitor.The core spun yarn can be used as a strain sensor with a wide strain range of 350%,high sensitivity,and the 0.1%of the external strain can be sensed.It has good cycle stability and durability.It can be used to monitor different human movement deformation,and can sense small changes in sound.As a flexible supercapacitor,it has high area specific capacitance(761.2 m F/cm~2)and stable cycle durability(it is still stable under different external strains and bending angles).The experimental results show that the core spun yarn can achieve the composite function of strain sensing and energy storage at the same time,which provides a reference for the preparation of multifunctional wearable flexible electronic devices.In the third part of this paper,weft knitted spacer fabric is immersed in CNT solution and dried for many times to minimize the resistance per unit length.Then,pyrrole is polymerized to prepare multifunctional weft knitted spacer fabric(WSP-CNT-PPy).The sensor has multi-dimensional sensing characteristics of tensile strain and compressive strain,with a wide range of tensile strain up to 450%,high sensitivity of compressive strain and cycle durability.The multi-dimensional sensing mechanism with both tensile strain and compressive strain can be used to monitor different human movements.Assembled into a three-dimensional flexible supercapacitor,the performance is stable,stable and durable under different external tension and compression.At the same time,the fabric has excellent electric heating performance,fast heating,low applied voltage,durable and obvious Joule effect.This experiment provides a new idea for the preparation of multi-functional flexible wearable electronic devices with multi-dimensional sensing,energy storage and electric heating.