Yang Shuguang, Zhang Yongjun, Guan Ying, Tan Shuaixia, Xu Jian, Cheng Shijing, Zhang Xiaoli
State Key Laboratory of Polymer Physics and Chemistry, Joint Laboratory of Polymer Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100080, China.
Soft Matter. 2006 Jul 20;2(8):699-704. doi: 10.1039/b606923a.
Hydrogen-bonded films of poly(vinylpyrrolidone) (PVPON) and poly(acrylic acid) (PAA) were built on a silicon and quartz surface using the layer-by-layer (LBL) assembly technique. Upon incubation, PVPON and PAA chains in the film can attain high-level miscibility and the film becomes homogeneous and transparent. TGA and elemental analysis indicate that the water content of the incubated PVPON-PAA film is only ∼4%. FT-IR proved that at high temperature these water molecules can be easily driven out of the film. When the incubated film was characterized with a spectrometer, it exhibited Fabry-Pérot fringes in the UV-visible-NIR spectrum. Such Fabry-Pérot fringes, sensitive to the change of water content in the film, were applied to study drying, drying-rewetting cycle, and humidity-responsive behavior of the film. The film exhibited reversible swelling-deswelling behavior during the incubation-heating cycles. The film thickness was found to decrease ∼10% upon drying. When the dry film was exposed to different humidity environments, it was found that the optical thickness of the film has a linear relationship with ambient humidity.
采用层层组装（LBL）技术，在硅和石英表面构建了聚（乙烯基吡咯烷酮）（PVPON）和聚（丙烯酸）（PAA）的氢键薄膜。经过孵育后，薄膜中的PVPON和PAA链可实现高度混溶，薄膜变得均匀且透明。热重分析（TGA）和元素分析表明，孵育后的PVPON-PAA薄膜的含水量仅约为4%。傅里叶变换红外光谱（FT-IR）证明，在高温下这些水分子可轻易从薄膜中驱出。当用光谱仪对孵育后的薄膜进行表征时，其在紫外-可见-近红外光谱中呈现出法布里-珀罗条纹。这种对薄膜中含水量变化敏感的法布里-珀罗条纹被用于研究薄膜的干燥、干燥-再湿润循环以及湿度响应行为。在孵育-加热循环过程中，薄膜呈现出可逆的溶胀-消溶胀行为。发现干燥后薄膜厚度降低约10%。当将干燥后的薄膜暴露于不同湿度环境时，发现薄膜的光学厚度与环境湿度呈线性关系。
