文献阅读-纳米石墨烯材料用于人体状态监测

# 1. 主要内容与摘要

- 题目
High Performance Strain Sensor Based on Carbon Black/Graphene / Ecoflex for Human Health Monitoring and Vibration Signal Detection
基于炭黑/石墨烯/Ecoflex的高性能人体健康监测和振动信号检测应变传感器
- 摘要
Inrecentyears,therehasbeenasignificant surgeof interest inflexible strainsensors within thedomains ofwearable electronics andhuman−computer interaction.
近年来，在可穿戴电子设备和人机交互领域出现了一种重要的非柔性应变传感器。
However, as these fieldscontinue toadvance rapidly, thereisanurgent needto improve thecomprehensive performance offlexible strainsensors including sensitivity, sensing range,response speed,anddurability. Inthisstudy,weaddress thisissuebytransferring carbon black/ graphene (CB/Gr) conductive nanocomposites ontothesurface of anEcoflex flexible substrate, which hasbeenpretreated using sandpaper toenhance adhesion.
然而，随着这些领域的持续快速发展，迫切需要提高柔性应变传感器的综合性能，包括灵敏度、传感范围、响应速度和耐用性。在这项研究中，我们通过将炭黑/石墨烯（CB/Gr）导电纳米复合材料转移到anEcoflex柔性基底的表面来解决这个问题，该基底已经用砂纸预处理以增强附着力。
The resulting flexible strainsensor exhibits high sensitivity, with a gauge factor of 51.4,while offering a wide sensing range of 100%. Notably, this sensor demonstrates high performance across various aspects, including afastresponse time (60ms) and excellent durability (up to 4000 stretching−releasing cycles). The versatility of this sensor is evident initsability to effectively monitor both small strain activities, such as speech recognition, and larger strain activities, such as elbowbending. Moreover, the sensor hasdemonstrated outstanding performance in various application scenarios, including human health andmotion condition monitoring as well as acoustic wave and vibration signals detection. Consequently, this highlights the sensor’s remarkable adaptability and substantial potential for wide-range applications in these domains.
该柔性应变传感器具有高灵敏度，augefactor为51.4，同时提供100%的宽传感器范围。值得注意的是，该传感器在各个方面都表现出高性能，包括最快响应时间（60毫秒）和出色的耐用性（高达4000次拉伸释放循环）。这种传感器的多功能性是显而易见的，可以有效地监控小应变活动，如语音识别，和大应变活动，如弯腰。此外，该传感器在各种应用场景中表现出出色的性能，包括人体健康和运动状态监测以及声波和振动信号检测。因此，这种高亮显示了传感器非凡的适应性和在这些领域广泛应用的巨大潜力。

# 2. 引言

## 2.1 论点1

Limited by high rigidity and limited strain capacity (strain ε < 5%), traditional metal or semiconductor based strain sensors are difficult to use in wearable electronic devices.1−4 Withthe rapiddevelopment ofmedical health andhuman−computer interaction, thereisanurgent needtodevelop newstrain sensors thatcanadapttothesefields.Theexcellent flexibility, ductility, andbiocompatibility offlexible strainsensors give themunique advantages inthesefields.Flexible strainsensors canbedivided intoseveral types, including resistive,5,6 capacitive,7 piezoresistive,8 andtriboelectric 9,10 sensors; among them, resistive strain sensors areregarded asan important andwidely applicable branch duetotheirabilityto effectively detect mechanical strainsignals andtheirsimple fabrication processes. However, someexisting resistive strain sensors haveshortcomings suchaslowsensitivity, 11 small sensing range,12 lowdurability, 13 andslowresponse speed,14 whichlimitthedevelopment ofresistive strainsensors inthe fieldsofhuman−computer interaction andwearable electronics. Therefore, in order to adapt to the development of thesefields,itisurgent todevelop flexible strainsensors with anexcellent comprehensive performance.
受高刚性和有限应变能力（应变ε<5%）的限制，传统的基于金属或半导体的应变传感器很难在可穿戴电子设备中使用。1-4随着医疗健康和人机交互的快速发展，迫切需要开发能够适应这些领域的新型应变传感器。柔性应变传感器优异的柔韧性、延展性和生物相容性使其在这些领域具有独特的优势。柔性应变传感器可分为几种类型，包括电阻式、5，6电容式、7压阻式、8摩擦电式、9，10传感器；其中，电阻应变传感器因其能够有效检测机械应变信号和制作工艺简单而成为一个重要且应用广泛的分支。然而，现有的电阻应变传感器存在灵敏度低、传感范围小、耐久性差、响应速度慢等缺点，限制了电阻应变传感器在人机交互和可穿戴电子领域的发展。因此，为了适应这些领域的发展，迫切需要开发综合性能优良的柔性应变传感器。
The fabrication process of flexible strain sensors primarily involves the integration of conductive micro/nano materials with flexible polymer materials. The most commonly used conductive micro/nano materials forpreparing flexible strain sensors include carbon materials (carbon black(CB),carbon nanotubes (CNTs), graphene (Gr),etc.),metalnanowires and nanoparticles (suchassilvernanowires, silvernanoparticles, goldnanoparticles, etc.),andcarbon/nanogen compounds (MXene).15−19 Inaddition, somenatural orsynthetic nanocomposites arealsousedtoprepare electronic skinandstrain sensors andexhibit excellent performance. Carbon black and graphene are frequently selected as materials for constructing conductive networks inflexible strainsensors duetotheiradvantageous properties,
可伸缩应变传感器的制造过程主要包括导电微/纳米材料与柔性聚合物材料的集成。用于制备柔性应变传感器的最常用导电微/纳米材料包括碳材料（炭黑（CB）、碳纳米管（CNTs）、石墨烯（Gr）等。）、金属纳米线和纳米粒子（如银纳米线、银纳米粒子、金纳米粒子等。），以及碳/纳米化合物（MXene）。15 19此外，一些天然或合成纳米复合材料也用于修复电子皮肤和应变传感器，并表现出优异的性能。20，21炭黑和石墨烯经常被选为构建导电网络的材料。
electrical conductivity, a large surface area,goodcyclicstability, andcost-effectiveness. Forinstance, Lianetal.employed 3D printing tofabricate aflexible strainsensor utilizing carbon blackastheconductive material, resulting inasensor that exhibited exceptional stability.
如：电导率、较大的表面积、良好的循环稳定性和成本效益。例如，Lianetal。采用3D打印技术制造了一种利用碳黑色传导材料的可伸缩应变传感器，从而使传感器表现出非凡的稳定性。
Zhang etal.developed a flexible conductive layerbyblending graphene withaflexible polymer tofabricate asandwich-structured strainsensor, which demonstrated exceptional stability.
张等开发了一种柔性导电层，将石墨烯与柔性聚合物共混，制成了一种三明治结构的应变传感器，具有优异的稳定性。
Notably, interfacial contact behavior between layered graphene sheets allows the graphene-based conductive network tomaintain connectivity evenundersubstantial strain.Simultaneously, smaller-sized CB particles servetofillvoidswithin theconductive layerand establish connections between conductive particles, resulting in adenser conductive network.
值得注意的是，层状石墨烯片之间的界面接触行为允许石墨烯基导电网络即使在物质应变下也能保持连接性。同时，较小尺寸的CB颗粒在导电层内形成空洞，并在导电颗粒之间建立连接，从而形成adenser导电网络。
Consequently, ajudicious blend of CBandgraphene inconstructing the sensor’s conductive network can enhance both the sensing range and sensitivity of the sensor. For instance, Liu et al.devised a sensor capable of measuring strain and pressure by applying a spray-coated dispersion of carbon black/graphene ontoa flexible paper substrate. Asstrain increased, graphene contributed tothestability ofthesensor’s conductive network, whileincreasing pressure prompted CBtofillgaps,thereby augmenting thesensor’s electrical conductivity. Nevertheless, theutilization offlexible paperasthesubstrate forthestrain sensor undoubtedly constrained itsstrain range, witha maximum straincapacity of only1.8%. 
因此，在传感器的导电网络中合理混合碳和石墨烯可以提高传感器的感应范围和灵敏度。例如，Liuetal。设计了一种传感器，能够通过在柔性纸基底上喷涂炭黑/石墨烯分散体来测量应变和压力。随着应变的增加，石墨烯有助于传感器导电网络的稳定性，而增加的压力促使碳填充间隙，从而增加传感器的导电性。然而，可降解纸作为应变传感器基底的利用无疑限制了其应变范围，最大应变能力仅为1.8%。
The material of the flexible base determines the sensing range of the sensor. The main flexible materials used in the existing flexible strainsensors include Ecoflex, polydimethylsiloxane (PDMS), thermoplastic polyurethane (TPU), and styrene−ethylene−butylene−styrene (SEBS).
柔性底座的材料决定了传感器的感应范围。现有柔性应变传感器使用的主要柔性材料包括Ecoflex、聚二甲基硅氧烷（PDMS）、热塑性聚氨酯（TPU）和苯乙烯——乙烯——丁烯——苯乙烯（SEBS）。
Because of thesimple preparation process (simple mixing andmixing of glueAandglueB),goodtensile properties (tensile factorof about600%), andgoodhuman compatibility, Ecoflex iswidely usedinthefieldofflexible strainsensors. Forexample, Antonio etal.prepared ahigh-tensile strainsensor basedoncarbon nanotubes andEcoflex, whichhadastrainsensing rangeofup to300%, butitsresponse timeandrecovery timeweretoo large(600and800ms,respectively). 
由于制备工艺简单（胶水和胶水的简单混合）、良好的拉伸性能（拉伸系数约为600%）和良好的人体相容性，Ecoflex广泛用于现场可伸缩应变传感器。例如，Antonio等人制备了基于碳纳米管和ECOFLEX的高强度应变传感器，其应变传感范围高达300%，但响应时间和恢复时间过长（分别为600ms和800ms）。
Zhong et al.usedtwo nozzles toheatandcureEcoflex substrates andmultiwall carbon nanotubes/Ecoflex composites together, andthey obtained aflexible strainsensor withhighsensitivity (GF= 165.3) andlargestrainrange(0−300%), whichhadexcellent conductivity, buttheheating andcuring process ofthesensor wasdifficult tocontrol. 
钟等。使用两个喷嘴对Ecoflex基底和多壁碳纳米管/Ecoflex复合材料进行加热和固化，获得了高灵敏度（GF=165.3）和大应变范围（0-300%）的柔性应变传感器，具有优异的导电性，但传感器的加热和固化过程难以控制。

## 2.2 论点2

While enhancing thecomprehensive performance ofthe sensor, itisalsoessential toemploy asimple andcontrollable fabrication method tomeettherequirements ofmasssensor production.在提高传感器综合性能的同时，采用简单可控的制造方法来满足质量传感器生产的要求是非常必要的。Herein, thisstudypresents ahigh-performance flexible strainsensorbasedonCB/Gr/Ecoflex. Theconductive network ofthesensor isconstructed withgranular carbon blackandlamellar graphene. Ecoflex, which hasexcellent tensile properties andasimple curing process, isselected to prepare theflexible substrate ofthesensor. Byusingan inverted sandpaper moldtoformmicropits onthesurface of theEcoflex flexible substrate, thesurface areaoftheflexible substrate isincreased without affecting itsmechanical properties, which facilitates more conductive composite materials to adhere totheflexible substrate andincreases thenumber of conductive particles attracted toeachother,building aclosely connected andmoreadhesive conductive layer. Not only is the preparation process ofthesensor simple, butalsothesensor shows excellent comprehensive performance.
在此，本研究提出了一种基于CB/Gr/Ecoflex的高性能柔性应变传感器。传感器的传导网络由颗粒炭黑和层状石墨烯构成。Ecoflex具有优异的拉伸性能和简单的固化工艺，被用来制备传感器的柔性基底。通过使用倒置的砂纸模具在柔性基板表面形成微坑，柔性基板的表面积增加而不影响其机械性能，这有利于更多的导电复合材料粘附到柔性基板上，并增加相互吸引的导电颗粒的数量，形成连接紧密且粘性更强的导电层。传感器的制备工艺不仅简单，而且综合性能优异。

# 3. 试验部分

2.1.Materials. Anhydrous ethanol waspurchased fromAladdin Chemical Reagent Co.,Ltd.Carbon blackwithadiameter of approximately 50nmandsingle-layer graphene withathickness of1 nmandwidth of200−1000 nmwerepurchased fromSuzhou Tanfeng Graphene Technology Co.,Ltd.Ecoflex 00-30waspurchased fromSmooth-On Co.,Ltd.,andsodium dodecylbenzenesulfonate (SDBS) dispersant waspurchased fromSinopharm Reagent Co.,Ltd. 2.2.Preparation ofCB/Gr Conductive Ink. Amixture ofcarbon black(CB)andsingle-layer graphene (Gr)isprepared inanhydrous ethanol ataweight ratioof5:1.Theanhydrous ethanol toCBratiois setat10:1,andasmallamount ofSDBSisaddedinaratioofCBto SDBSat10:1byweight toenhance thedispersion anddissolution of CBandGr.TheCBandGrmixture isstirred ataroomtemperature of300rpmforover3htoensure complete dissolution andthorough mixing inethanol. Subsequently, themixture issubjected to ultrasonication for30mintodisrupt intermolecular forces and obtain astableCB/Gr conductive ink.Thisconductive inkmaintains excellent dispersion andconductivity forupto36h. 2.3.Preparation ofCB/Gr/Ecoflex Flexible Strain Sensor. A flatmoldisprepared byattaching sandpaper toitsbottom, resulting in amolddepthof0.8mmandthereby ensuring aflexible substrate thickness of0.8mm.Ecoflex adhesives AandBaremixedina1:1 ratioandpoured intothemold.Themixture isdriedat55 °Cfor5 min,andthedriedflexible membrane iscarefully peeled offfromthe mold. Thesurface oftheflexible membrane exhibits numerous irregular micropits. Subsequently, themembrane iscutintoastrip measuring 30mm × 15mm(length × width). Theprepared flexible substrate isimmersed inthepreviously prepared CB/Gr conductive inkandstirred for3htoallowforthedeposition ofconductive nanocomposites ontotheflexible substrate. Thestirred flexible substrate isthenplaced inadrying ovenanddriedat55 °Cfor10 mintoensure thecomplete evaporation ofanhydrous ethanol. This process yieldsaCB/Gr conductive layerwithexcellent adhesion on theflexible substrate’s microporous surface structure. Byusingsilver pasteandcopper wirestoleadoutelectrodes atbothendsofthe sensing membrane, aflexible strainsensor withhighsensitivity anda widesensing rangeisobtained. Finally, performance testing and sensitivity calculation arecarried outonthesensor. 26 2.4.Characterization andMeasurements. Thelinearmotor controller (WNMC400, Beijing MicroNanoOptics Instrument Co., Ltd.)isapplied tocontrol themotion ofthelinearmotor, thereby performing atensile testonthesensor. Adigital multimeter (DMM6500 61/2,Keithley) isadopted totracktheresistance changes ofthesensor during thetest.Theforce−strain relationship ofthe sensor isevaluated byusingatensile testing machine (I5−200 N, JinanFangyuan TestInstrument Co.,Ltd.).Thesurface morphology ofthesensorisobserved usingascanning electron microscope (SEM, JEOLJSM7500F). TheDCregulated power supply (eTM-L603SPL +(60V3A)) isapplied totracktherelationship between thevoltage andcurrent ofthesensor.

### 2.1.材料制备

无水乙醇购自马丁化学试剂有限公司，碳黑直径约为50纳米，单层石墨烯厚度为1纳米，宽度为200-1000纳米，单层石墨烯购自苏州谭峰石墨烯科技有限公司，EcoFlex 00-30购自Smooth-On有限公司，十二烷基苯磺酸钠（SDBS）分散剂购自国药试剂有限公司。

### 2.2.CB/Gr导电油墨的制备。

在无水乙醇中制备了炭黑（CB）和单层石墨烯（Gr）的混合物，重量比为5：1。无水乙醇以10：1的比例配制，少量的SDBSi以10：1的重量加入到SDBSat中，以增强CBandGr的分散和溶解。将带状混合物在300转/分的室温下搅拌超过3℃，以确保完全溶解并完全混合到乙醇中。随后，对混合物进行30分钟的超声波处理，以破坏分子间力，获得稳定的Cb/Gr导电墨水。这种导电墨水保持优异的分散性和导电性长达36小时。

### 2.3.CB/Gr/Ecoflex柔性应变传感器的制备。

通过将砂纸贴在底部制备一个平面模具，产生0.8毫米的固化深度，从而确保0.8毫米的可固化基材厚度。Ecoflex粘合剂和bareMixed以1：1的比例混合并倒入模具中。混合物在55℃下干燥5分钟，然后小心地从模具中剥离干燥的柔性膜。柔性膜表面有许多不规则的微坑。随后，膜的尺寸为30毫米× 15毫米（长×宽）。将制备的柔性基底浸入预先制备的CB/Gr导电墨水中，并搅拌3h，以允许导电纳米复合材料沉积到柔性基底上。将干燥的柔性基底放在烘箱中，在55℃下干燥10分钟，以确保无水乙醇完全蒸发。该工艺在柔性基底的微孔表面结构上产生具有优异附着力的SACB/Gr导电层。通过在传感膜的两端使用银糊和铜线作为输出电极，获得了一种灵敏度高、范围宽的柔性应变传感器。最后对传感器进行了性能测试和灵敏度计算。26 2.4。特性和测量。采用直线电机控制器（北京微纳光学仪器有限公司WNMC400）控制直线电机的运动，从而对传感器进行可测性测试。采用数字万用表（DMM6500 61/2，Keithley）跟踪传感器在测试过程中的电阻变化。使用传感器试验机（济南方圆测试仪有限公司I5200N）评估传感器的力——应变关系。使用扫描电子显微镜（SEM，JEOLJSM7500F）观察传感器的表面形态。调节电源（eTM-L603SPL+（60V3A））用于跟踪传感器的电压和电流之间的关系。

# 参考文献资料

High Performance Strain Sensor Based on Carbon Black/Graphene/ Ecoflex for Human Health Monitoring andVibration Signal Detection