Huang Hai-Jun, Ning Xiang, Zhou Min-Bo, Sun Tao, Wu Xue, Zhang Xin-Ping
School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China.
Guangdong Provincial Engineering Technology R&D Center of Electronic Packaging Materials and Reliability, South China University of Technology, Guangzhou 510640, China.
ACS Appl Mater Interfaces. 2021 Apr 21;13(15):18021-18032. doi: 10.1021/acsami.1c02422. Epub 2021 Apr 12.
Fabrication of metal nanoparticle (NP)-based strain sensors with both a broad working range and linearity range is still a significant challenge. Typically, homogeneous conductive percolation networks are indispensable for linear sensing performance, whereas inhomogeneous microstructures may inevitably arise under large strain due to the formation of defects in rigid NPs. In this study, a sandwich-structured strain sensor with an extraordinarily large stretchability (800%) yet self-healing property is fabricated by three-dimensional printing using a liquid metal-like Ag NP ink. The strain sensor shows an initial conductivity of 248 S cm, a good linearity in two strain ranges, and a long-term stability after undergoing 5000 cycles under a strain level of 100%. Such highly comprehensive sensing performance is attributed to the unique structure of the Ag NP ink, in which Ag NPs coalesce together after room-temperature sintering triggered by chlorides, and then, the sintered Ag aggregates tend to form continuous conductive networks through hydrogen bonds between polyacrylic acid and carboxymethylcellulose. Further, the free flow of Ag aggregates is the root cause that leads to the change of relative resistance as demonstrated by finite element simulation. This Ag NP-based strain sensor shows high potential for application in monitoring human knuckle motion.
制造具有宽工作范围和线性范围的基于金属纳米颗粒（NP）的应变传感器仍然是一项重大挑战。通常，均匀的导电渗流网络对于线性传感性能是必不可少的，而由于刚性纳米颗粒中缺陷的形成，在大应变下可能不可避免地出现不均匀的微观结构。在本研究中，通过使用类液态金属的银纳米颗粒墨水进行三维打印，制造了一种具有超大拉伸性（800%）且具有自愈性能的三明治结构应变传感器。该应变传感器的初始电导率为248 S/cm，在两个应变范围内具有良好的线性，并且在100%应变水平下经历5000次循环后具有长期稳定性。这种高度综合的传感性能归因于银纳米颗粒墨水的独特结构，其中银纳米颗粒在氯化物引发的室温烧结后聚结在一起，然后，烧结的银聚集体倾向于通过聚丙烯酸和羧甲基纤维素之间的氢键形成连续的导电网络。此外，银聚集体的自由流动是导致相对电阻变化的根本原因，有限元模拟证明了这一点。这种基于银纳米颗粒的应变传感器在监测人体关节运动方面具有很高的应用潜力。
