柔性石墨烯传感带拉伸传感性能

将石墨烯织带作为基材覆合于弹性针织面料上,以制备柔性石墨烯传感带。在伸长率为0~25%时,通过定伸长拉伸试验测试不同初始长度的石墨烯传感带电阻与伸长率关系、灵敏度、重复性以及稳定性。结果表明:当伸长率小于10%时,柔性石墨烯传感带的电阻增长速率较快,而当伸长率超过10%后,电阻变化较小;伸长率为0~10%,其灵敏系数可达6.0以上;5次重复性拉伸测试发现,该传感带具有良好的重复性及稳定性。研究表明,该柔性石墨烯传感带在服装用人体数据采集如长度测量等方面有一定的应用性。

基于纳米导电炭黑和碳纤维材料的柔性拉伸传感材料响应特性的研究

导电硅橡胶作为敏感材料具有良好的柔韧性和电阻变形特性。以聚二甲基硅氧烷橡胶为基材,通过加入导电材料纳米炭黑、碳纤维,制备了炭黑/PDMS、碳纤维/PDMS复合柔性导电材料,研究了材料的微观形态、渗流过程特性和拉伸-电阻率变化响应特性,以及材料微观结构变化与电阻特性的构效关系。结果表明,复合材料的渗流阈值为4%、用量超过12%后,复合材料的体积电阻率变化减小。复合材料的质量分数为12%时,炭黑/PDMS体积电阻为10-0.55Ω·m,碳纤维/PDMS体积电阻率为100.82Ω·m。炭黑/PDMS复合材料对拉伸形变具有优良的响应特性,体积电阻变化率对伸长率的响应灵敏度可达266.7。碳纤维/PDMS复合材料的灵敏度低于炭黑/PDMS灵敏度,材料对拉伸形变均有十分迅速的响应速度,且性能稳定。炭黑/PDMD材料响应值Δρ/ρ约为碳纤维/PDMD材料的4倍,是良好的传感器材料。

可穿戴拉伸传感织物的研究进展

综述了近年来拉伸传感织物在智能纺织品领域的新研究进展,介绍了以金属纤维、导电碳材料以及导电聚合物为基础的拉伸传感织物的制备方法,分析各织物传感性能的优劣,总结了目前可穿戴拉伸传感织物应用中存在的问题,并对下一步的主要发展方向提出了设想与展望。

弹性导电复合纤维的制备及其应变与温度传感性能

为满足柔性可穿戴传感器的多功能传感需求,实现应变和温度传感具有重大的意义。采用湿法纺丝技术制备聚(3,4-乙烯二氧噻吩)-聚苯乙烯磺酸(PEDOT:PSS)/银纳米线(AgNWs)/聚氨酯(PU)弹性复合导电纤维,研究其拉伸应变传感性能和温度传感性能。结果表明:当AgNWs质量分数为20%,(PEDOT:PSS)与PU质量比为1∶3时,纤维热电性能达到最佳,电导率为47.4 S/cm,塞贝克系数为13.8μV/K,功率因数为902.7 nW/(m·K^(2)),此外,该弹性导电复合纤维具有良好的力学性能,断裂伸长率可达800%,能够检测0%~90%的应变范围,并在100次循环拉伸/回复下依旧保持良好稳定性;同时可将其作为温度传感器,快速检测人体与环境温度。

1-D polymer ternary composites:Understanding materials interaction, percolation behaviors and mechanism toward ultra-high stretchable and super-sensitive strain sensors

A series of 1-D polymer ternary composites based on poly(styrene-butadiene-styrene)(SBS)/carbon nanotubes(CNTs)/few-layer graphene(FLG) conductive fibers(SCGFs)were prepared via wet-spinning. Employed as ultra-high stretchable and super-sensitive strain sensors, the ternary composite fiber materials’ interaction, percolation behaviors and mechanism were systematically explored. The resultant SCGFs-based strain sensors simultaneously exhibited high sensitivity, superior stretchability(with a gauge factor of 5,467 under 600% deformation) and excellent durability under different test conditions due to excellent flexibility of SBS, the synergistic effect of hybrid conductive nanofibers and the strong π-π interaction. Besides, the conductive networks in SBS matrix were greatly affected by the mass ratio of CNTs and FLG, and thus the piezoresistive performances of the strain sensors could be controlled by changing the content of hybrid conductive fillers. Especially, the SCGFs with 0.30 wt.%CNTs(equal to their percolation threshold 0.30 wt.%) and 2.7 wt.% FLG demonstrated the highest sensitivity owing to the bridge effect of FLG between adjacent CNTs. Whereas, the SCGFs with 1.0 wt.% CNTs(higher than their percolation threshold) and 2.0 wt.% FLG showed the maximum strain detection range(600%) due to the welding connection caused by FLG between the contiguous CNTs. To evaluate the fabricated sensors, the tensile and the cyclic mechanical recovery properties of SCGFs were tested and analyzed. Additionally, a theoretical piezoresistive mechanism of the ternary composite fiber was investigated by the evolution of conductive networks according to tunneling theory.

Eggshell-inspired membrane—shell strategy for simultaneously improving the sensitivity and detection range of strain sensors

The tradeoff between sensitivity and detection range(maximum and minimum stretchability)is a key limitation in strain sensors;to resolve this,we develop an efficient and novel strategy herein to fabricate a highly sensitive and stretchable strain sensor inspired by the membrane-shell structure of poultry eggs.The developed sensor comprises a soft and stretchable surface-grafting polypyrrole(s-PPy)film(acting as the membrane)and a brittle Au film(acting as the shell),wherein both films complement each other at the electrical and mechanical levels.Au forms cracks under strain contributing to its high sensitivity and low detection limit,and s-PPy can bridge Au cracks and increase stretchability which has not been used in strain sensors before.The surface-grafting strategy not only enhances interface adhesion but also tunes the brittle property of native PPy to render it stretchable.Utilizing the synergetic effect of the membrane-shell complementary structure,the strain sensors achieve ultrahigh sensitivity(>10^(7)),large stretchability(100%),and an ultralow detection limit(0.1%),demonstrating significant progress in the field of strain sensors.The membrane-shell(Au/s-PPy)-structured strain sensor can successfully detect finger motion,wrist rotation,airflow fluctuation,and voice vibration;these movements produce strain in the range of subtle to marked deformations.Results evidence the ultrahigh performance and bright application prospects of the developed strain sensors.

A skin-like stretchable colorimetric temperature sensor

Wearable and stretchable physical sensors that can conformally contact on the surface of organs or skin provide a new opportunity for human-activity monitoring and personal healthcare. Particularly, various attempts have been made in exploiting wearable and conformal sensors for ther- mal characterization of human skin. In this respect, skin- mounted thermochromic films show great capabilities in body temperature sensing. Thermochromic temperature sensors are attractive because of their easy signal analysis and optical recording, such as color transition and fluorescence emission change upon thermal stimuli. Here, desirable mechanical properties that match epidermis are obtained by physical crosslinking of polydiacetylene （PDA） and transparent elas- tomeric polydimethylsiloxane （PDMS） networks. The result- ing PDA fdm displayed thermochromic and thermo- fluorescent transition temperature in the range of 25-85℃, with stretchability up to 300% and a skin-like Young＇s mod- ulus of -230 kPa. This easy signal-handling provides excellent references for further design of convenient noninvasive sen- sing systems.