Center for Nanophase Materials Sciences , Oak Ridge National Laboratory , P.O. Box 2008, Oak Ridge , Tennessee 37831-6496 , United States.
Center for Functional Nanomaterials , Brookhaven National Laboratory , Upton , New York 11973 , United States.
ACS Appl Mater Interfaces. 2018 Sep 19;10(37):31745-31754. doi: 10.1021/acsami.8b08072. Epub 2018 Sep 5.
Oxygen and water vapor sensing properties are investigated in metal-oxide-hybrid polymer nanocomposite thin films generated by infiltration synthesis, which incorporates molecular ZnO into the matrix of SU-8 polymer, a common negative-tone photoresist. The hybrid thin films display 20-fold higher gravimetric responses to oxygen and water vapor than those of control ZnO thin films in the dark. An additional 50-500% enhanced responses are detected under UV irradiation. The overall enhanced gravimetric response in the hybrid film is attributed to the ZnO molecules distributed in the polymer matrix, whereas the UV enhancement is explained by the light-induced, reversible generation of hydrophilic fluoroantimonic acid from triarylsulfonium hexafluoroantimonate photoacids, which leads to the increased surface potential and adsorption energies for oxygen and water. A gravimetric sensor based on a series of ZnO-infiltrated SU-8 films under UV excitation enables 96% accurate classification of water and oxygen environment with sub 10 mTorr detection limits. The results demonstrate UV-induced fully reversible surface hydrophilicity of ZnO/SU-8 hybrid nanocomposites.
金属氧化物-聚合物纳米复合薄膜的渗透合成及氧水汽传感性能研究，将分子 ZnO 掺入 SU-8 聚合物（一种常见的负性光刻胶）基体中。与暗态下的对照 ZnO 薄膜相比，该复合薄膜对氧水汽的重量响应提高了 20 倍。在紫外光照射下，检测到额外的 50-500%的增强响应。在混合膜中整体增强的重量响应归因于分布在聚合物基体中的 ZnO 分子，而 UV 增强则可以通过三芳基硫鎓六氟锑酸盐光酸光诱导可逆生成亲水性氟锑酸来解释，这导致表面电势和氧水汽的吸附能增加。基于一系列在紫外光激发下的 ZnO 渗透 SU-8 薄膜的重量传感器能够以 96%的准确率对水和氧气环境进行分类，检测下限低于 10 mTorr。研究结果表明，ZnO/SU-8 复合纳米复合材料具有紫外诱导的完全可逆的表面亲水性。
