引 en
×

分享给微信好友或者朋友圈

使用微信“扫一扫”功能。

具有多层结构的可拉伸可折叠自修复有机硅导电弹性体∗

  • 单玉兴1

    机 构：

    1. 西南科技大学环境友好能源材料国家重点实验室 绵阳 621010

    ×
  • ， 杨镜鑫2

    机 构：

    2. 西南科技大学材料科学与工程学院 绵阳 621010

    ×
  • ， 王进2

    机 构：

    2. 西南科技大学材料科学与工程学院 绵阳 621010

    ×
  • ， 符亚军2

    机 构：

    2. 西南科技大学材料科学与工程学院 绵阳 621010

    ×
  • ， 胡程耀2

    机 构：

    2. 西南科技大学材料科学与工程学院 绵阳 621010

    ×
  • ， 闫辉3

    机 构：

    3. 绵阳麦思威尔科技有限公司 绵阳 621010

    ×
  • ， 黄亚文1

    机 构：

    1. 西南科技大学环境友好能源材料国家重点实验室 绵阳 621010

    ×

1. 西南科技大学环境友好能源材料国家重点实验室 绵阳 621010；
2. 西南科技大学材料科学与工程学院 绵阳 621010；
3. 绵阳麦思威尔科技有限公司 绵阳 621010；

Stretchable and Foldable Self-healable Conductive Silicon Elastomer with Multi-layered Structure

  • SHAN Yuxing1

    Affiliation：

    1. State Key Laboratory of Environment-friendly Energy Materials, Southwest University of Science and Technology, Mianyang 621010 , China

    ×
  • ， YANG Jingxin2

    Affiliation：

    2. School of Material Science and Engineering, Southwest University of Science and Technology, Mianyang 621010 , China

    ×
  • ， WANG Jin2

    Affiliation：

    2. School of Material Science and Engineering, Southwest University of Science and Technology, Mianyang 621010 , China

    ×
  • ， FU Yajun2

    Affiliation：

    2. School of Material Science and Engineering, Southwest University of Science and Technology, Mianyang 621010 , China

    ×
  • ， HU Chengyao2

    Affiliation：

    2. School of Material Science and Engineering, Southwest University of Science and Technology, Mianyang 621010 , China

    ×
  • ， YAN Hui3

    Affiliation：

    3. Mianyang Maxwell Technology Co., Ltd, Mianyang 621010 , China

    ×
  • ， HUANG Yawen1

    Affiliation：

    1. State Key Laboratory of Environment-friendly Energy Materials, Southwest University of Science and Technology, Mianyang 621010 , China

    ×

1. State Key Laboratory of Environment-friendly Energy Materials, Southwest University of Science and Technology, Mianyang 621010 , China；
2. School of Material Science and Engineering, Southwest University of Science and Technology, Mianyang 621010 , China；
3. Mianyang Maxwell Technology Co., Ltd, Mianyang 621010 , China；

作者简介:

单玉兴,男,1995年出生,硕士。主要研究方向为动态键高分子材料。E-mail:shanyuxing512@163.com;

黄亚文(通信作者),男,1981年出生,博士,研究员,博士研究生导师。主要研究方向为动态键高分子材料。E-mail:huangyawenswust@163.com;

符亚军,男,1987年出生,博士,特聘副教授,硕士研究生导师。主要研究方向为低维材料。E-mail:fuyajun@swust.edu.cn

中图分类号:TG456

文献标识码:A

DOI:10.11933/j.issn.1007-9289.20210416001

参考文献 1
GENG W H Y,CUTHBERT T J,MENON C.Conductive thermoplastic elastomer composite capacitive strain sensors and their application in a wearable device for quantitative joint angle prediction[J].Acs Applied Polymer Materials,2021,3(1):122-129.
查找原文
参考文献 2
GONG H,CAI C,GU H J,et al.Flexible and wearable strain sensor based on electrospun carbon sponge/polydimethylsiloxane composite for human motion detection[J].Rsc Adv,2021,11(7):4186-4193.
查找原文
参考文献 3
PAUL S J,ELIZABETH I,GUPTA B K.Ultrasensitive wearable strain sensors based on a VACNT/PDMS thin film for a wide range of human motion monitoring [J].Acs Appl Mater Inter,2021,13(7):8871-8879.
查找原文
参考文献 4
WANG H Q,LI J C,YU X,et al.Cellulose nanocrystalline hydrogel based on a choline chloride deep eutectic solvent as wearable strain sensor for human motion[J].Carbohyd Polym,2021,255:117443.
查找原文
参考文献 5
WANG J,DU Y,ZHANG Q,et al.A study of highly sensitive wearable strain sensor based on graphical sensitive units[J].J Sensors,2021,2021(8):1-9.
查找原文
参考文献 6
WEI J J,XIE J J,ZHANG P C,et al.Bioinspired 3D printable,self-Healable,and stretchable hydrogels with multiple conductivities for skin-like wearable strain sensors[J].Acs Appl Mater Inter,2021,13(2):2952-2960.
查找原文
参考文献 7
谢安,张亦旸,张明.大形变条件下的导电弹性体研究进展 [J].中国材料进展,2018,37(10):811-816.XIE A,ZHANG Y Y,ZHANG M.Research progress in conductive elastomers applied under the condition of large deformation[J].Materials China,2018,37(10):811-816.(in Chinese)
查找原文
参考文献 8
王世茹,夏巍,刘述梅,等.导电热塑性弹性体研究进展 [J].广东化工,2020,47(4):98-100.WANG S R,XIA W,LIU S M,et al.Research progress in the conductive thermoplastic elastomer [J].Guangdong Chemical Industry,2020,47(4):98-100.(in Chinese)
查找原文
参考文献 9
AMJADI M,KYUNG K U,PARK I,et al.Stretchable,skinmountable,and wearable strain sensors and their potential applications:A Review [J].Advanced Functional Materials,2016,26(11):1678-1698.
查找原文
参考文献 10
AMJADI M,YOON Y J,PARK I.Ultra-stretchable and skinmountable strain sensors using carbon nanotubes-Ecoflex nanocomposites[J].Nanotechnology,2015,26(37):375501.
查找原文
参考文献 11
XIAO G F,WANG Y,ZHANG H,et al.Cellulose nanocrystal mediated fast self-healing and shape memory conductive hydrogel for wearable strain sensors[J].Int J Biol Macromol,2021,170:272-283.
查找原文
参考文献 12
XUN X C,ZHANG Z,ZHAO X,et al.Highly robust and selfpowered electronic skin based on tough conductive self-healing elastomer[J].Acs Nano,2020,14(7):9066-9072.
查找原文
参考文献 13
ZHANG L J,XIONG H,WU Q,et al.Constructing hydrophobic protection for ionic interactions toward water,acid,and baseresistant self-healing elastomers and electronic devices[J].Sci China Mater,2021,64(7):1780-1790.
查找原文
参考文献 14
LAI G W,CHANG S J,LEE J T,et al.Conductive microcapsules for self-healing electric circuits [J].Rsc Adv,2015,5(126):104145-104148.
查找原文
参考文献 15
SONG Y K,CHUNG C M.Repeatable self-healing of a microcapsule-type protective coating[J].Poly.Chem,2013,4(18):4940-4947.
查找原文
参考文献 16
张慧慧,李孟宇,封翔楠,等.外援型自修复微胶囊材料的最新研究进展[J].工程塑料应用,2019,47(4):134-137.ZHANG H H,LI M Y,FENG X N,et al.Review of the latest research on extrinsic microcapsule self-healing materials [J].Engineering Plastics Application,2019,47(4):134-137.(in Chinese)
查找原文
参考文献 17
李海燕,张丽冰,李杰,等.外援型自修复聚合物材料研究进展[J].化工进展,2014,33(1):133-139.LI H Y,ZHANG L B,LI J,et al.Research progresses in extrinsic self-healing polymer materials [J].Chemical Industry and Engineering Progress,2014,33(1):133-139.(in Chinese)
查找原文
参考文献 18
ADZIMA B J,KLOXIN C J,BOWMAN C N.Externally triggered healing of a thermoreversible covalent network via selflimited hysteresis heating [J].Advanced Materials,2010,22(25):2784-2787.
查找原文
参考文献 19
CANADELL J,GOOSSENS H,KLUMPERMAN B.Self-healing materials based on disulfide links[J].Macromolecules,2011,44(8):2536-2541.
查找原文
参考文献 20
DENG G H,TANG C M,LI F Y,et al.Covalent cross-linked polymer gels with reversible sol-gel transition and self-healing properties[J].Macromolecules,2010,43(3):1191-1194.
查找原文
参考文献 21
NICOLAY R,KAMADA J,VAN WASSEN A,et al.Responsive gels based on a dynamic covalent trithiocarbonate cross-linker [J].Macromolecules,2010,43(9):4355-4361.
查找原文
参考文献 22
ZHENG P W,MCCARTHY T J.A Surprise from 1954:siloxane equilibration is a simple,robust,and obvious polymer selfhealing mechanism [J].J.Am.Chem.Soc.,2012,134(4):2024-2027.
查找原文
参考文献 23
蒋业华,李本新,孙翀,等.本征型自修复橡胶材料的研究进展[J].橡胶工业,2021,68(4):313-319.JIANG Y H,LI B X,SUN C,et al.Research progress on intrinsic self-healing rubber[J].China Rubber Industry,2021,68(4):313-319.(in Chinese)
查找原文
参考文献 24
杜逸纯,赵博文,温妍,等.本征型自修复高分子材料的研究进展[J].材料科学与工程学报,2020,38(3):509-517.DU Y C,ZHAO B W,WEN Y,et al.Research progress of intrinsic self-healing polymer materials[J].Journal of Materials Science and Engineering,2020,38(3):509-517.(in Chinese)
查找原文
目录contents

    摘要

    自修复导电弹性体在可穿戴设备领域有着巨大的应用潜力,但其导电性能和稳定性难以兼顾。 在自修复弹性体基材表面依次构建粗糙微米结构和金属导电层,构建形成新型导电弹性体(Ag / SiO2 / B-BZn-PDMS)。 制备获得基于硼酸酯/ 配位双交联的新型自修复有机硅弹性体(B-BZn-PDMS),其抗拉强度为 0. 52±0. 05 MPa,断裂伸长率 98±5%,6 h 室温修复率可达 98. 1%。 研究结果表明:双层导电层具有良好的导电性能(电阻 4 Ω),经过 11 次拉伸循环,导电性能仍然保持。 此外,Ag / SiO2 / B-BZn-PDMS 导电性能可在室温 20 min 自修复,电阻修复率可达 93%以上。 提出利用自修复弹性体以及粗糙结构构建柔性耐用导电弹性体的思路,为低成本高性能导电涂层开发提供了新的途径。

    Abstract

    Self-healable conductive elastomers have found great application potential in wearable devices. However, most of current self-healable conductive elastomers are difficult to combine high conductivity and good durability. A micro-structured bilayered conductive coating (Ag / SiO2 / B-BZn-PDMS) was fabricated by sequentially constructing microstructure and metal conductive layers. The self-healing elastomer was prepared with boronic ester/ coordination dual cross-linked network (B-BZn-PDMS). B-BZn-PDMS has the ultimate tensile strength and strain ratio at breaking of 0. 52 ± 0. 05 MPa and 98 ± 5%. The self-healing efficiency at room temperature for 6 h can reach to 98. 1%. The bilayered conductive structure exhibited good conductivity (R= 4 Ω). After 11 times of strain cycles, the good conductive performance was still remained. Moreover, after self-healing, the conductive performance of Ag / SiO2 / B-BZn-PDMS can be recovered at room temperature after 20 min. The self-healing efficiency was above 93%. Overall, a new idea is proposed to construct flexible durable conductive elastomer by introducing self-healable silicon elastomer and rough structure and a route is provided to conductive elastomer with low cost and high performance.

    关键词

    动态键 ； 自修复 ； 导电 ； 聚硅氧烷

  • 0 前言

  • 近年来,可拉伸、可折叠的导电弹性体在可穿戴设备[1-8]、健康检测、智能皮肤[9] 等方面引起了人们广泛关注。其中可穿戴设备可以直接贴在人体皮肤表面,实时监测人体活动,这些力学性能需要像人类皮肤一样具有高延展性( ε>100%,ε 为应变)、高柔韧性、生物相容性和轻量化[10]。对于智能皮肤和可穿戴应变传感器设备,在长时间的使用过程中不可避免地会遇到弯曲、拉伸、刮擦、划痕等物理损伤,并且由于需要适应长期的拉伸/收缩周期性应变,动态耐久性是一个非常重要的指标。应变传感器性能的下降,主要由于聚合物在高应变疲劳和塑性形变后导电材料会产生微裂纹甚至断裂,并造成电子器件导电性能下降,甚至造成整个器件的损坏,极大地缩短了电子器件的使用寿命[11-13]。人们发现皮肤在受到损伤后会在短时间修复伤口,通过模仿这一性能研发了多种自愈合的材料,应用于可伸缩的电子器件中。

  • 目前导电自修复材料按修复方式主要分为两种:外援型自修复材料(修复剂预埋到微胶囊或微脉管中) [14-17]和本征型自修复材料(通过动态可逆键实现修复) [18-24]。本征型自修复导电材料相较于外援型自修复材料可以通过动态键的交换实现多次的自愈。目前,常采用在弹性体表面引入金属导电层的方法来实现损伤弹性体导电的修复。由于,弹性体与银层的韧性不同,拉伸后金属导电层容易产生裂纹,导致导电性能下降。当前的研究热点是引入液体金属导电层,可以显著提高弹性体耐用性,然而材料成本较高。

  • 鉴于此,本文采用基于动态键双交联结构的B-BZn-PDMS弹性体,在表面构建微米级粗糙结构。考虑到磁控溅射镀膜技术具有高速低温、膜层与基底结合力好等优势,通过磁控溅射在其表面沉积一层纳米级的导电层,构建出可折叠的自修复有机硅导电弹性体Ag/SiO2/B-BZn-PDMS,成功地实现了室温快速修复微裂纹,极大地延长了导电弹性体的使用寿命。

  • 1 试验

  • 1.1 试验材料及样品制备

  • 试验材料如表1所示。

  • 2-甲酰基苯硼酸氯化锌(CHO-BZn)的合成:将甲酰基苯基硼酸(0.5g)溶解在20mL乙醇中,再加入1mL氯化锌溶液( 0.23g/mL)。将该溶液在25℃下搅拌24h,最后将产物在50℃ 条件下真空干燥24h得到橙色液体。

  • 表1 试验材料

  • Table1 Test materials

  • 4-醛基苯基环三硼氧烷(B-B):3,4-二羟基苯甲醛( 0.40g),2-甲酰基苯硼酸 ( 0.44g),无水MgSO4(0.44g),四氢呋喃(20mL)装入50mL的烧杯中,加入搅拌子,在室温条件下反应24h。离心后取出上清液,旋蒸后在50℃下真空干燥得到暗粉色固体。

  • 氨基丙基-聚二甲基硅氧烷(AP-PDMS):将八甲基环四硅氧烷(50.02g),3-氨基丙基(二乙氧基)甲基硅烷(14.30g),六甲基二硅氧烷(1.04g), 二甲基亚砜(DMSO,0.20mL),KOH (0.095g) 和H2O(1.50mL)在100mL圆底烧瓶中混合。在氮气环境中、90℃下将溶液搅拌4h;随后,在减压60℃ 的条件下除去水。将该溶液在90℃ 下再搅拌6h, 旋转蒸发除去溶剂,最后将产物在50℃下真空干燥获得产物(65g)。

  • 硼酸酯双交联的聚硅氧烷的合成 ( B-BZn-PDMS):取AP-PDMS(1.00g),分散到10mL的四氢呋喃中,加入B-B(0.019g), CHO-BZn(250 μL), 充分振荡,将所得溶液在室温下滴到聚四氟乙烯 (PTFE)板(7cm×5cm)上,静置12h,交联后形成B-BZn-PDMS弹性体。

  • 导电弹性体的制备( Ag/SiO2/B-BZn-PDMS): 取7~40nm的疏水纳米SiO2(0.1g),分散到10mL的四氢呋喃溶液中,加入AP-PDMS ( 0.10g),B-B (0.001 9g),CHO-BZn(25 μL),充分超声震荡将混合的溶液喷涂到B-BZn-PDMS弹性体表面,喷涂时喷枪嘴距离样品~20cm,气压为0.3~0.4MPa,喷涂2或3次,在室温条件下放置6h。将制备的有机硅弹性( SiO2/B-BZn-PDMS)置于磁控溅射腔室中, 控制溅射功率60W,工作气压1.0Pa,沉积时间10min,沉积金属Ag导电薄膜,获得最终的弹性导电体(Ag/SiO2/B-BZn-PDMS)。

  • 1.2 结构表征及力学性能测试

  • 傅里叶红外(FTIR):溴化钾研磨压片在其表面滴涂样品,采用Nicolet FTIR 5700在400~4 000cm-1 的频率范围内进行红外测试。核磁氢谱 ( 1H NMR):以氘代氯仿为溶剂将样品分散在核磁管中, 采用Bruker 600NMR进行测试。扫描电镜(SEM): 样品表面喷金处理,采用Tescan Maia3电子显微镜在15kV加速电压下进行扫描观察。自修复性能测试:将样条切成30mm×8mm×0.2mm,通过WDW-5D(中国)以10mm/min的拉伸速度在室温条件下进行力学测试,通过破坏前和修复后的应力计算修复效率公式为 σ/σ0 ×100%(σ 为修复后样条的拉伸强度,σ0 为初始样条的拉伸强度)。电学性能测试: 通过ProsKit MT-1280(中国)测试导电体的导电性能,测试点相距1cm。循环拉伸/收缩测试: 将30mm×8mm×0.2mm的样条循环拉伸/收缩5次后(~20%的应变)通过扫描电镜观察导电弹性体表面拉伸前后导电银层的形貌变化。

  • 2 试验结果与讨论

  • 2.1 B-BZn-PDMS的结构表征

  • 硼酸酯/配位双交联的硅橡胶弹性体制备路线如图1所示,首先采用醛基苯硼酸与锌离子配位合成硼酸配位化合物(CHO-BZn),同时以该化合物和醛基苯硼酸为交联剂与侧基氨基聚硅氧烷反应可获得双交联有机硅弹性体。侧基氨基聚硅氧烷(AP-PDMS)的结构表征结果如下: 1H NMR谱图检测到氨丙基的特征峰在2.1×10-6,通过积分计算出氨丙基的含量为10%,如图2a所示。红外光谱图(图3) 显示在1 580cm-1 处N-H的伸缩振动峰。通过2-甲酰基苯硼酸和3,4-二羟基苯甲醛反应制备出硼酸酯(B-B), 1H NMR谱图(图2b)显示2-甲酰基苯硼酸和3,4-二羟基苯甲醛的醛基氢信号( 10.2 × 10-6 和9.7×10-6),证明了硼酸酯的合成。通过2-甲酰基苯硼酸与氯化锌在乙醇溶液反应制备出配位化合物2-甲酰基苯硼-氯化锌( CHO-BZn),由1H NMR谱图(图2c)可发现硼酸和醛基的特征峰(3.8和10.0 × 10-6)。将CHO-BZn和B-B加入到AP-PDMS中制备出双交联的聚硅氧烷弹性体(B-BZn-PDMS),从红外光谱所示在1 638cm-1 处为C=N的特征峰,1 348cm-1 和1 305cm-1 是B-O的特征峰,证明了B-BZn-PDMS的双交联结构。

  • 图1 B-BZn-PDMS的制备过程

  • Fig.1 Synthesis of the B-BZn-PDMS elastomer

  • 图2 原料和聚合物的核磁共振氢谱

  • Fig.2 1H NMR of Raw materials and polymers

  • 2.2 B-BZn-PDMS力学性能和修复性能测试

  • 采用硼酸酯和硼酸-金属配位双交联网络构建自修复弹性体,其中硼酸酯作为共价键起到强交联作用,决定材料的力学强度,而硼酸-金属配位键作为非共价键发挥牺牲键作用,提高材料韧性。本课题组在国内外较早提出可利用硼酸-金属配位构建自修复弹性体,研究结果表明硼酸-金属配位键虽然键能较弱,但修复性能优异,通过引入动态共价键构建双交联结构,在保留修复性能的同时提高了力学性能。力学性能测试结果(图4和表2)显示,B-BZn-PDMS-1的抗拉强度为0.52±0.05MPa,断裂伸长率98±5%。加入2%的B-B的B-BZn-PDMS-2的抗拉强度为0.54 ± 0.05MPa,断裂伸长率95 ± 5%。当继续提高B-B ∶ CHO-BZn到3 ∶ 7时,B-BZn-PDMS-3的抗拉强度为0.62±5%,断裂伸长率77± 5%。结果表明随着B-B含量的提高有利于抗拉强度的增大,断裂伸长率减小。这一结果与硼酸酯的共价键和硼锌金属配位键的强弱符合。当配比为2 ∶8时力学性能最优。

  • 图3 AP-PDMS和B-BZn-PDMS的红外光谱

  • Fig.3 FTIR spectra of AP-PDMS and B-BZn-PDMS

  • 图4 不同比例B-BZn-PDMS在不同修复时间下的应力应变曲线

  • Fig.4 Stress-strain curves of different proportion B-BZn-PDMS under different repair time

  • 表2 B-BZn-PDMS结构和性能

  • Table2 Structure and properties of the B-BZn-PDMS

  • 将弹性体B-BZn-PDMS从中间切断,再将伤口对接,修复一段时间后修复的弹性体仍具有可拉伸性能。自修复测试结果表明,B-BZn-PDMS-1的修复效果最好,6h修复到98.1%,断裂强度恢复到0.51±0.05MPa,断裂伸长率修复到94±5%。 12h的修复效果与6h基本一致。 B-BZn-PDMS-2修复24h修复效率可达72%,断裂强度修复到0.39MPa,断裂伸长率修复到86.4%。而B-BZn-PDMS-3修复性能最差, 24h修复率为62.9%, 断裂强度为0.39MPa,断裂伸长率为28.4%。可以看出,随着CHO-BZn配位键的增多,双交联的聚硅氧烷弹性体修复速度越快,修复性能的越好。 B-B动态共价键提高了弹性体的力学性能,而引入CHO-BZn提高了修复性能。

  • 将有机硅弹性体涂敷在基材上,可形成弹性体涂层,进一步对弹性体涂层的自修复性能进行考察。采用手术刀划伤弹性体涂层,通过扫描电镜可观察弹性体B-BZn-PDMS在受到划伤后会产生10 μm的划痕,在室温条件下修复20min后,伤口基本愈合。通常化学交联PDMS遭到同样的手术刀划伤后会产生30 μm的划痕,修复一段时间后伤口仍无法愈合(图5)。这一结果表明,弹性体B-BZn-PDMS划痕的修复不是通过物理回弹实现的,而是在室温条件下聚硅氧烷中引入的动态金属配位键和动态硼酸酯键实现的。这些动态键可以在室温的条件下发生可逆交换,可以在伤口处重建,而且由于动态键的动态性质,B-BZn-PDMS可以实现多次修复。

  • 2.3 导电弹性体Ag/SiO2/B-BZn-PDMS结构表征

  • 双交联聚硅氧烷弹性体(B-BZn-PDMS)具有优异的力学性能和自修复性能。为了实现弹性体导电,常用的方法是在弹性体表面引入金属导电层。由于弹性体与导电薄膜的韧性不同,拉伸后金属导电薄膜容易产生裂纹,导致导电性能下降。当前的研究热点是,引入液体金属导电层,可以显著提高弹性体耐用性,然而材料成本较高。为此,本文提出一种基于微米结构的双层导电层,即在B-BZn-PDMS喷涂一层SiO2/B-BZn-PDMS,之后通过磁控溅射在表面沉积金属Ag导电薄膜(如图6a),可以清楚看到表面形成银色的金属薄膜( 如图6b)。由SEM (图6c)可以看到,金属Ag薄膜表面较为粗糙,高低起伏较大,存在明显沟壑,表现为大量微米级的凸起连接成膜。金属Ag薄膜表面的粗糙形貌是SiO2/B-BZn-PDMS表面的SiO2 聚集形成的。最终得到的这种堆积折叠结构大大提高了金属导电薄膜的韧性。同时粗糙结构的引入增大了导电薄膜的接触面积和导电通路,拉伸后也更容易实现导电的修复。电阻测试结果表明,引入微米涂层的导电弹性体电阻为4 Ω,明显小于目前文献报道的导电自修复弹性体电阻。

  • 图5 B-BZn-PDMS和PDMS的裂纹修复SEM图

  • Fig.5 SEM images of B-BZn-PDMS and PDMS after repair

  • 图6 Ag/SiO2/B-BZn-PDMS导电弹性体的制备过程及表面形貌

  • Fig.6 Preparation process and surface morphology of Ag/SiO2/B-BZn-PDMS conductive elastomer

  • 2.4 导电弹性体Ag/SiO2/B-BZn-PDMS导电性

  • 由于Ag/SiO2/B-BZn-PDMS导电弹性体具有出色的回弹性能和导电性能,制备出了应变传感器。伸直的手指电阻为4.1 Ω,弯曲后电阻增大到25.1 Ω(如图7)。导电弹性体在使用中不仅需经历多次反复拉伸/收缩,同时还可能出现裂纹甚至断裂等物理损伤,因此导电弹性体应在多种情况下能保证良好的导电性能。本文通过循环拉伸/收缩测试Ag/SiO2/B-BZn-PDMS的电阻随拉伸次数的变化,来评价弹性体导电性能在拉伸/收缩作用下的稳定性。如图8c所示, Ag/SiO2/B-BZn-PDMS经过拉伸后,电阻显著上升到180 Ω 左右, 表明这一弹性体同时可作为应力传感器。回弹后Ag/SiO2/B-BZn-PDMS电阻恢复到14 Ω,且经过11次反复拉伸后,电阻依然能恢复到19 Ω。相比之下,没有引入微米结构的导电弹性体Ag/B-BZn-PDMS经过1或2次拉伸回复后,电阻已不可测, 表明弹性体失去了导电能力。进一步对Ag/SiO2/B-BZn-PDMS和Ag/B-BZn-PDMS弹性体拉伸后表面导电金属银层的形貌进行了SEM表征( 图8a、 8b),结果表明Ag/B-BZn-PDMS表面导电银层出现了明显的破碎现象,说明由于金属导电银层和弹性体间刚柔性不匹配,导致金属导电银层在拉伸和回弹过程产生了断裂。而从Ag/SiO2/B-BZn-PDMS的SEM图片可以看出,经过多次的拉伸/收缩后并未出现导电层的破碎,这是由于Ag/SiO2/B-BZn-PDMS的微米级粗糙结构可以将原本一体的导电银层转变为数量众多的导电单元,降低了柔性不匹配的问题,所以不会产生大量裂纹,而且微米级粗糙结构增大了导电层的比表面积,提高了导电修复概率。导电银层经过多次拉伸后依然保持良好的稳定性,证明微米结构的引入显著提升了导电薄膜的耐用性(图8)。

  • 图7 Ag/SiO2/B-BZn-PDMS在拉伸/弯曲下的电阻响应行为

  • Fig.7 Resistance response behavior of Ag/SiO2/B-BZn-PDMS under tension/bending

  • 图8 粗糙结构对弹性体拉伸形貌的影响

  • Fig.8 Effect of rough structure on the tensile morphology of elastomer

  • 进一步考察Ag/SiO2/B-BZn-PDMS的导电自修复性能。将导电自修复弹性体Ag/SiO2/B-BZn-PDMS与发光二极管灯泡串联,发光二极管被点亮, 两端电阻为4 Ω。用手术刀从导电弹性体中间完全切断,电路断开,灯泡熄灭(图9a)。将导电弹性体Ag/SiO2/B-BZn-PDMS伤口完全对齐重新连接在一起,LED被点亮,但导电性能并不稳定,稍有移动LED就会熄灭。这是由于下层弹性体并未修复,导致上层导电层接触容易错位。在室温条件下修复20min后,导电弹性体的导电性能可保持稳定,灯泡与最初亮度一样,电阻恢复到~4.3 Ω,电导率基本恢复初始值,修复效率达到93%以上(图9c)。因此多层导电自修复弹性体中各层分别发挥如下功能:①自修复弹性体作为可拉伸载体,同时其自修复功能保证导电性能的稳定性;②纳米粒子层赋予表面粗糙结构,有利于形成数量众多的导电单元,从而增大了导电通路和导电界面,使得导电弹性体具有较好的耐用性;③银层赋予弹性体导电性。这一结构设计为新型耐用性导电弹性体制备提供了思路。

  • 3 结论

  • 基于粗糙结构和双交联网络结构构建多层自修复导电弹性体,显著提高导电弹性体耐用性同时降低成本,为柔性导体制备提供了新的方案。主要结论有:

  • (1)提出通过动态硼酸酯和金属配位键双交联网络构建自修复有机硅弹性体(B-BZn-PDMS)的策略,研究发现B-BZn-PDMS不仅具有较高的抗拉强度,同时可在室温下高效快速自修复。

  • (2)通过传统导电涂层与粗糙结构结合,导电涂层稳定性显著提高,经受多次弯折后导电性能仍能恢复。与液体金属相比,这一导电材料制备简单, 成本低,导电性能相当,具有一定优势。

  • (3)以B-BZn-PDMS为基础,结合微米级粗糙导电结构,构建形成Ag/SiO2/B-BZn-PDMS导电弹性体。该导电弹性体具有良好的耐用性,可经受反复拉伸和物理损伤后修复导电性能。这一基于粗糙结构的多层自修复弹性体有望应用在柔性电子、人工穿戴、软体机器人等领域中。

  • 图9 Ag/SiO2/B-BZn-PDMS导电性能修复照片。

  • Fig.9 Conductivity repair photos Ag/SiO2/B-BZn-PDMS

  • 参考文献

    • [1] GENG W H Y,CUTHBERT T J,MENON C.Conductive thermoplastic elastomer composite capacitive strain sensors and their application in a wearable device for quantitative joint angle prediction[J].Acs Applied Polymer Materials,2021,3(1):122-129.

    • [2] GONG H,CAI C,GU H J,et al.Flexible and wearable strain sensor based on electrospun carbon sponge/polydimethylsiloxane composite for human motion detection[J].Rsc Adv,2021,11(7):4186-4193.

    • [3] PAUL S J,ELIZABETH I,GUPTA B K.Ultrasensitive wearable strain sensors based on a VACNT/PDMS thin film for a wide range of human motion monitoring [J].Acs Appl Mater Inter,2021,13(7):8871-8879.

    • [4] WANG H Q,LI J C,YU X,et al.Cellulose nanocrystalline hydrogel based on a choline chloride deep eutectic solvent as wearable strain sensor for human motion[J].Carbohyd Polym,2021,255:117443.

    • [5] WANG J,DU Y,ZHANG Q,et al.A study of highly sensitive wearable strain sensor based on graphical sensitive units[J].J Sensors,2021,2021(8):1-9.

    • [6] WEI J J,XIE J J,ZHANG P C,et al.Bioinspired 3D printable,self-Healable,and stretchable hydrogels with multiple conductivities for skin-like wearable strain sensors[J].Acs Appl Mater Inter,2021,13(2):2952-2960.

    • [7] 谢安,张亦旸,张明.大形变条件下的导电弹性体研究进展 [J].中国材料进展,2018,37(10):811-816.XIE A,ZHANG Y Y,ZHANG M.Research progress in conductive elastomers applied under the condition of large deformation[J].Materials China,2018,37(10):811-816.(in Chinese)

    • [8] 王世茹,夏巍,刘述梅,等.导电热塑性弹性体研究进展 [J].广东化工,2020,47(4):98-100.WANG S R,XIA W,LIU S M,et al.Research progress in the conductive thermoplastic elastomer [J].Guangdong Chemical Industry,2020,47(4):98-100.(in Chinese)

    • [9] AMJADI M,KYUNG K U,PARK I,et al.Stretchable,skinmountable,and wearable strain sensors and their potential applications:A Review [J].Advanced Functional Materials,2016,26(11):1678-1698.

    • [10] AMJADI M,YOON Y J,PARK I.Ultra-stretchable and skinmountable strain sensors using carbon nanotubes-Ecoflex nanocomposites[J].Nanotechnology,2015,26(37):375501.

    • [11] XIAO G F,WANG Y,ZHANG H,et al.Cellulose nanocrystal mediated fast self-healing and shape memory conductive hydrogel for wearable strain sensors[J].Int J Biol Macromol,2021,170:272-283.

    • [12] XUN X C,ZHANG Z,ZHAO X,et al.Highly robust and selfpowered electronic skin based on tough conductive self-healing elastomer[J].Acs Nano,2020,14(7):9066-9072.

    • [13] ZHANG L J,XIONG H,WU Q,et al.Constructing hydrophobic protection for ionic interactions toward water,acid,and baseresistant self-healing elastomers and electronic devices[J].Sci China Mater,2021,64(7):1780-1790.

    • [14] LAI G W,CHANG S J,LEE J T,et al.Conductive microcapsules for self-healing electric circuits [J].Rsc Adv,2015,5(126):104145-104148.

    • [15] SONG Y K,CHUNG C M.Repeatable self-healing of a microcapsule-type protective coating[J].Poly.Chem,2013,4(18):4940-4947.

    • [16] 张慧慧,李孟宇,封翔楠,等.外援型自修复微胶囊材料的最新研究进展[J].工程塑料应用,2019,47(4):134-137.ZHANG H H,LI M Y,FENG X N,et al.Review of the latest research on extrinsic microcapsule self-healing materials [J].Engineering Plastics Application,2019,47(4):134-137.(in Chinese)

    • [17] 李海燕,张丽冰,李杰,等.外援型自修复聚合物材料研究进展[J].化工进展,2014,33(1):133-139.LI H Y,ZHANG L B,LI J,et al.Research progresses in extrinsic self-healing polymer materials [J].Chemical Industry and Engineering Progress,2014,33(1):133-139.(in Chinese)

    • [18] ADZIMA B J,KLOXIN C J,BOWMAN C N.Externally triggered healing of a thermoreversible covalent network via selflimited hysteresis heating [J].Advanced Materials,2010,22(25):2784-2787.

    • [19] CANADELL J,GOOSSENS H,KLUMPERMAN B.Self-healing materials based on disulfide links[J].Macromolecules,2011,44(8):2536-2541.

    • [20] DENG G H,TANG C M,LI F Y,et al.Covalent cross-linked polymer gels with reversible sol-gel transition and self-healing properties[J].Macromolecules,2010,43(3):1191-1194.

    • [21] NICOLAY R,KAMADA J,VAN WASSEN A,et al.Responsive gels based on a dynamic covalent trithiocarbonate cross-linker [J].Macromolecules,2010,43(9):4355-4361.

    • [22] ZHENG P W,MCCARTHY T J.A Surprise from 1954:siloxane equilibration is a simple,robust,and obvious polymer selfhealing mechanism [J].J.Am.Chem.Soc.,2012,134(4):2024-2027.

    • [23] 蒋业华,李本新,孙翀,等.本征型自修复橡胶材料的研究进展[J].橡胶工业,2021,68(4):313-319.JIANG Y H,LI B X,SUN C,et al.Research progress on intrinsic self-healing rubber[J].China Rubber Industry,2021,68(4):313-319.(in Chinese)

    • [24] 杜逸纯,赵博文,温妍,等.本征型自修复高分子材料的研究进展[J].材料科学与工程学报,2020,38(3):509-517.DU Y C,ZHAO B W,WEN Y,et al.Research progress of intrinsic self-healing polymer materials[J].Journal of Materials Science and Engineering,2020,38(3):509-517.(in Chinese)

  • 基本信息

    中图分类号: TG456
    文献标识码: A
    DOI: 10.11933/j.issn.1007-9289.20210416001

    基金信息

    四川省科技厅资助项目(2020YJ0333)；
    Supported by Sichuan Science and Technology Program(2020YJ0333).；

    引用信息

    稿件历史

    收稿日期: 2021-04-16

  • 参考文献

    • [1] GENG W H Y,CUTHBERT T J,MENON C.Conductive thermoplastic elastomer composite capacitive strain sensors and their application in a wearable device for quantitative joint angle prediction[J].Acs Applied Polymer Materials,2021,3(1):122-129.

    • [2] GONG H,CAI C,GU H J,et al.Flexible and wearable strain sensor based on electrospun carbon sponge/polydimethylsiloxane composite for human motion detection[J].Rsc Adv,2021,11(7):4186-4193.

    • [3] PAUL S J,ELIZABETH I,GUPTA B K.Ultrasensitive wearable strain sensors based on a VACNT/PDMS thin film for a wide range of human motion monitoring [J].Acs Appl Mater Inter,2021,13(7):8871-8879.

    • [4] WANG H Q,LI J C,YU X,et al.Cellulose nanocrystalline hydrogel based on a choline chloride deep eutectic solvent as wearable strain sensor for human motion[J].Carbohyd Polym,2021,255:117443.

    • [5] WANG J,DU Y,ZHANG Q,et al.A study of highly sensitive wearable strain sensor based on graphical sensitive units[J].J Sensors,2021,2021(8):1-9.

    • [6] WEI J J,XIE J J,ZHANG P C,et al.Bioinspired 3D printable,self-Healable,and stretchable hydrogels with multiple conductivities for skin-like wearable strain sensors[J].Acs Appl Mater Inter,2021,13(2):2952-2960.

    • [7] 谢安,张亦旸,张明.大形变条件下的导电弹性体研究进展 [J].中国材料进展,2018,37(10):811-816.XIE A,ZHANG Y Y,ZHANG M.Research progress in conductive elastomers applied under the condition of large deformation[J].Materials China,2018,37(10):811-816.(in Chinese)

    • [8] 王世茹,夏巍,刘述梅,等.导电热塑性弹性体研究进展 [J].广东化工,2020,47(4):98-100.WANG S R,XIA W,LIU S M,et al.Research progress in the conductive thermoplastic elastomer [J].Guangdong Chemical Industry,2020,47(4):98-100.(in Chinese)

    • [9] AMJADI M,KYUNG K U,PARK I,et al.Stretchable,skinmountable,and wearable strain sensors and their potential applications:A Review [J].Advanced Functional Materials,2016,26(11):1678-1698.

    • [10] AMJADI M,YOON Y J,PARK I.Ultra-stretchable and skinmountable strain sensors using carbon nanotubes-Ecoflex nanocomposites[J].Nanotechnology,2015,26(37):375501.

    • [11] XIAO G F,WANG Y,ZHANG H,et al.Cellulose nanocrystal mediated fast self-healing and shape memory conductive hydrogel for wearable strain sensors[J].Int J Biol Macromol,2021,170:272-283.

    • [12] XUN X C,ZHANG Z,ZHAO X,et al.Highly robust and selfpowered electronic skin based on tough conductive self-healing elastomer[J].Acs Nano,2020,14(7):9066-9072.

    • [13] ZHANG L J,XIONG H,WU Q,et al.Constructing hydrophobic protection for ionic interactions toward water,acid,and baseresistant self-healing elastomers and electronic devices[J].Sci China Mater,2021,64(7):1780-1790.

    • [14] LAI G W,CHANG S J,LEE J T,et al.Conductive microcapsules for self-healing electric circuits [J].Rsc Adv,2015,5(126):104145-104148.

    • [15] SONG Y K,CHUNG C M.Repeatable self-healing of a microcapsule-type protective coating[J].Poly.Chem,2013,4(18):4940-4947.

    • [16] 张慧慧,李孟宇,封翔楠,等.外援型自修复微胶囊材料的最新研究进展[J].工程塑料应用,2019,47(4):134-137.ZHANG H H,LI M Y,FENG X N,et al.Review of the latest research on extrinsic microcapsule self-healing materials [J].Engineering Plastics Application,2019,47(4):134-137.(in Chinese)

    • [17] 李海燕,张丽冰,李杰,等.外援型自修复聚合物材料研究进展[J].化工进展,2014,33(1):133-139.LI H Y,ZHANG L B,LI J,et al.Research progresses in extrinsic self-healing polymer materials [J].Chemical Industry and Engineering Progress,2014,33(1):133-139.(in Chinese)

    • [18] ADZIMA B J,KLOXIN C J,BOWMAN C N.Externally triggered healing of a thermoreversible covalent network via selflimited hysteresis heating [J].Advanced Materials,2010,22(25):2784-2787.

    • [19] CANADELL J,GOOSSENS H,KLUMPERMAN B.Self-healing materials based on disulfide links[J].Macromolecules,2011,44(8):2536-2541.

    • [20] DENG G H,TANG C M,LI F Y,et al.Covalent cross-linked polymer gels with reversible sol-gel transition and self-healing properties[J].Macromolecules,2010,43(3):1191-1194.

    • [21] NICOLAY R,KAMADA J,VAN WASSEN A,et al.Responsive gels based on a dynamic covalent trithiocarbonate cross-linker [J].Macromolecules,2010,43(9):4355-4361.

    • [22] ZHENG P W,MCCARTHY T J.A Surprise from 1954:siloxane equilibration is a simple,robust,and obvious polymer selfhealing mechanism [J].J.Am.Chem.Soc.,2012,134(4):2024-2027.

    • [23] 蒋业华,李本新,孙翀,等.本征型自修复橡胶材料的研究进展[J].橡胶工业,2021,68(4):313-319.JIANG Y H,LI B X,SUN C,et al.Research progress on intrinsic self-healing rubber[J].China Rubber Industry,2021,68(4):313-319.(in Chinese)

    • [24] 杜逸纯,赵博文,温妍,等.本征型自修复高分子材料的研究进展[J].材料科学与工程学报,2020,38(3):509-517.DU Y C,ZHAO B W,WEN Y,et al.Research progress of intrinsic self-healing polymer materials[J].Journal of Materials Science and Engineering,2020,38(3):509-517.(in Chinese)

    • 手机扫一扫看