Poutanen Mikko, Ahmed Zafar, Rautkari Lauri, Ikkala Olli, Priimagi Arri
Department of Applied Physics, Aalto University, P.O. Box 15100, FI-00076, Aalto, Espoo, Finland.
Laboratory of Chemistry and Bioengineering, Tampere University of Technology, P.O. Box 541, FI-33101, Tampere, Finland.
ACS Macro Lett. 2018 Mar 20;7(3):381-386. doi: 10.1021/acsmacrolett.8b00093. Epub 2018 Mar 10.
Photoisomerization of azobenzene derivatives is a versatile tool for devising light-responsive materials for a broad range of applications in photonics, robotics, microfabrication, and biomaterials science. Some applications rely on fast isomerization kinetics, while for others, bistable azobenzenes are preferred. However, solid-state materials where the isomerization kinetics depends on the environmental conditions have been largely overlooked. Herein, an approach to utilize the environmental sensitivity of isomerization kinetics is developed. It is demonstrated that thin polymer films containing hydroxyazobenzenes offer a conceptually novel platform for sensing hydrogen-bonding vapors in the environment. The concept is based on accelerating the thermal - isomerization rate through hydrogen-bond-catalyzed changes in the thermal isomerization pathway, which allows for devising a relative humidity sensor with high sensitivity and quick response to relative humidity changes. The approach is also applicable for detecting other hydrogen-bonding vapors such as methanol and ethanol. Employing isomerization kinetics of azobenzenes for vapor sensing opens new intriguing possibilities for using azobenzene molecules in the future.
偶氮苯衍生物的光异构化是一种通用工具，可用于设计在光子学、机器人技术、微加工和生物材料科学等广泛应用中的光响应材料。一些应用依赖于快速的异构化动力学，而对于其他应用，双稳态偶氮苯更受青睐。然而，异构化动力学取决于环境条件的固态材料在很大程度上被忽视了。在此，开发了一种利用异构化动力学环境敏感性的方法。结果表明，含有羟基偶氮苯的聚合物薄膜为传感环境中的氢键蒸汽提供了一个概念上新颖的平台。该概念基于通过热异构化途径中氢键催化的变化来加速热异构化速率，这使得能够设计出对相对湿度变化具有高灵敏度和快速响应的相对湿度传感器。该方法也适用于检测其他氢键蒸汽，如甲醇和乙醇。利用偶氮苯的异构化动力学进行蒸汽传感为未来使用偶氮苯分子开辟了新的有趣可能性。
