关键词: 超分子离子材料, 咪唑阳离子, 湿度传感

Abstract:

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.

Key words: supramolecular ionic material, imidazolium, humidity sensing