柔性可拉伸碳纳米管复合薄膜及螺旋纤维的制备与气敏性能研究

Flexible wearable gas sensors have important applications in many fields, and the development of flexible and stretchable high-performance films, fibers and functional devices is an important challenge. In this project, we will directly synthesize large-area, high interconnected and conductive single-walled carbon nanotube (SWNT) films with a two-dimensional network structure, by chemical vapor deposition method. Gas-sensitive active materials will be doped or grafted into the SWNTs in a controlled manner, and these composite films will then be fabricated into stretchable fibers with a unique helical structure by dry spinning. We will study the gas adsorption and sensor applications of the composite SWNT films and fibers for harmful gases (NOx). Through the regulation of microstructure such as the network porosity, distribution, and morphology of active materials, we will prepare a series of composite films and helical fibers combining the SWNTs and those active organic or inorganic materials. Based on an interconnected two-dimensional SWNTs network structure, we will analyze adsorption/desorption processes and the underlying sensing mechanisms of different target gases. Furthermore, we will construct flexible, stretchable film- and fiber-based sensing devices that can work reliably under large-strain deformation or repeated stretching, and optimize the sensor performance such as sensitivity, selectivity and response/desorption rate to NOx. Our project results will push forward the development and application of high performance nanomaterial-based gas sensors.

柔性可穿戴气体传感器在很多领域有重要应用，开发柔性可拉伸的高性能薄膜、纤维材料和功能器件是目前面临的重要挑战。本项目采用化学气相沉积法直接合成连续大面积高联通、高导电的二维网络状单壁碳纳米管薄膜，可控掺杂或负载对气体敏感的活性物质，并将其纺成具有独特螺旋结构的可拉伸纤维，研究碳纳米管复合薄膜及纤维对有害气体（NOx为代表）的吸附性能和传感应用。项目将制备一系列基于碳纳米管和活性材料的复合薄膜及螺旋纤维，调控其微观结构包括孔隙率、活性物质的分布及形态等，基于互连的二维碳纳米管网络结构分析对目标气体的吸附脱附过程和传感机理，并优化对NOx气体响应的灵敏度、选择性以及吸/脱附速率等重要性能。构建柔性可拉伸的薄膜型及纤维型传感器件，能够在大变形或反复拉伸条件下稳定工作。项目的成果将对开发高性能纳米材料气体传感器起到有力的推动作用。

高性能气敏器件在环境监测、工业生产、医疗诊断和国防军事等诸多领域有着广泛的应用。作为典型纳米材料的碳纳米管（CNT），其独特的电子结构使得其费米能级附近的态密度容易因吸附而改变，从而引发体系宏观电阻的变化。再加上体积小、高导电、高强度和稳定性好，结构的多样性和可操作性使得碳纳米管在气体传感器的研发中显示出巨大的应用潜力。.项目执行期间，以第一作者或通讯作者发表了高水平学术论文27篇，其中SCI收录24篇，EI收录3篇；申请国家发明专利8项，已授权5项；培养了硕士研究生12名；培养了河南省自然科学基金优青1名，河南省高校科技创新人才1名。本项目从气敏材料的结构设计出发，深入了研究金属/金属氧化物或者高分子导电聚合物纳米颗粒和单壁碳纳米管网络的相互作用以及对应的复合体系对NOx为代表的有害气体的传感特性，开发了低温操作的可拉伸的高性能柔性气体传感器。其中碳纳米管/二氧化钛复合薄膜组装的气体传感器在室温下对50ppm的NO气体的电阻变化率达到41%，最低的NO检测限为1ppm。构建的柔性可拉伸薄膜型和纤维型传感器件，能够在大变形或反复拉伸条件下稳定工作。