Jia Zhixin, Li Zhangjie, Ma Shufei, Zhang Wenqiang, Chen Yongjun, Luo Yuanfang, Jia Demin, Zhong Bangchao, Razal Joselito M, Wang Xungai, Kong Lingxue
School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China.
Chongqing Key Laboratory of Green Synthesis and Applications, College of Chemistry, Chongqing Normal University, Chongqing 401331, China.
J Colloid Interface Sci. 2021 Feb 15;584:1-10. doi: 10.1016/j.jcis.2020.09.035. Epub 2020 Sep 18.
MXenes (two-dimensional early transition metal carbides and carbonitrides) possess both excellent conductivity and surface hydrophilicity, enabling more diverse potential applications. However, in flexible strain sensors, the flexible substrates are usually composed of hydrophobic elastomers such as thermoplastic polyurethane (TPU). To enhance the interactions between MXenes and hydrophobic. substrates, it is wiser to change the composition of the flexible substrate than to modify the surface of MXenes, so as to improve the interactions between the flexible substrate and MXenes without losing the excellent conductivity of MXene.
We introduce polyacrylonitrile (PAN) into TPU, and then fabricate a flexible TPU/PAN mat through electrospinning. A highly conductive and stretchable TiC MXene/TPU/PAN mat was then prepared by a simple dip-coating process. The interaction mechanism between TiC MXene nanosheets and TPU/PAN mat was investigated by XPS and FT-IR. Finally, we build the MXene/TPU/PAN mat into a flexible strain sensor with excellent properties.
By introducing PAN into flexible substrate, the interaction between TiC MXene and the flexible substrate was effectively improved without compromising TiC MXene's excellent conductivity. The MXene/TPU/PAN strain sensor possesses a wide sensing range (0-80%), a fast response (<140.6 ms), a low limit of detection (<0.1%), splendid coating adhesion and excellent durability (>1750 cycles). All of these properties are demanded in wearable electronics.
MXenes（二维早期过渡金属碳化物和碳氮化物）兼具优异的导电性和表面亲水性，具有更多样化的潜在应用。然而，在柔性应变传感器中，柔性基板通常由疏水性弹性体如热塑性聚氨酯（TPU）组成。为了增强MXenes与疏水性基板之间的相互作用，改变柔性基板的组成比修饰MXenes的表面更为明智，以便在不损失MXene优异导电性的情况下改善柔性基板与MXenes之间的相互作用。
我们将聚丙烯腈（PAN）引入TPU中，然后通过静电纺丝制备柔性TPU/PAN垫。随后通过简单的浸涂工艺制备了高导电性和可拉伸的TiC MXene/TPU/PAN垫。通过XPS和FT-IR研究了TiC MXene纳米片与TPU/PAN垫之间的相互作用机理。最后，我们将MXene/TPU/PAN垫制成具有优异性能的柔性应变传感器。
通过将PAN引入柔性基板中，有效改善了TiC MXene与柔性基板之间的相互作用，同时不影响TiC MXene的优异导电性。MXene/TPU/PAN应变传感器具有宽传感范围（0-80%）、快速响应（<140.6毫秒）、低检测限（<0.1%）、出色的涂层附着力和优异的耐久性（>1750次循环）。所有这些特性都是可穿戴电子产品所需要的。
