基于超分子离子晶体的湿度传感构效关系研究

相对湿度是许多领域的关键参数，环境湿度与人们的生活密切相关，因此对湿度进行测量和控制是各个领域中值得关注的问题之一. 在前期的研究中，作者制备了一种新型的超分子离子材料（SIM），它是由基于咪唑的双阳离子（如1,10-双（3-甲基咪唑-1-基）癸烷，C₁₀(mim)₂）和电活性二阴离子（如2,2'-连氮基-双（3-乙基苯并噻唑啉-6-磺酸），ABTS）组成的，发现其对湿度具有敏感且快速的响应. 在此基础上，本文制备了6种不同碳链（C₄，C₆，C₈，C₁₀，C₁₂，C₁₄）的咪唑基化合物，发现其中3种（C₁₀，C₁₂，C₁₄）可与ABTS形成水稳定的SIM. 循环伏安法、计时电流法以及石英晶体微量天平表征了这些超分子离子材料的湿度传感性能，发现基于C12的SIM具有最佳的湿度传感性能. 同时，SEM结果显示随着碳链的增加，离子材料的厚度变薄并且形态变得不规则. 因此，作者认为疏水作用和材料比表面积均会影响湿度传感的灵敏度. 本研究为发展新的湿度响应的离子传感材料奠定了基础.

Study on the Relationship between Structure of Supramolecular Ion Material and Performance of Humidity Sensing

Humidity measurement and control is one of the most notable issues in various areas, such as climate, industry, agriculture, electronics, especially human comfort and health. In our previous study, we have found that a new kind of supramolecular ionic material (SIM), consisting of an imidazolium-based dication (e.g., 1,10-bis(3-methylimidazolium-1-yl) decane, C₁₀(mim)₂) and electroactive dianionic (e.g., 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid), ABTS), shows ultrasensitive and ultrafast response towards humidity sensing. Herein we prepared six kinds of imidazolium-based dications with different carbon chain lengths (i.e., C₄, C₆, C₈, C₁₀, C₁₂, C₁₄), and found that three of them (i.e., C₁₀, C₁₂, C₁₄) could form water-stable SIM with ABTS. Cyclic voltammetry, chronoamperometry and quartz crystal microbalance were used to characterize the humidity sensing performance of these supramolecular ionic materials. The results show that the C₁₂-based SIM has the best humidity sensing performance compared with the other two kinds of SIM. Moreover, SEM images show that the thickness of the ionic material became thinner with the increase of the carbon chain length. We, thus, conclude that both the hydrophobic interaction and the specific surface area of SIMs would contribute to the performance of humidity response. This paper would lay the foundation for the development of new ionic compound for humidity sensing.