Saint-Gobain Research Paris , 39 quai Lucien Lefranc 93303 Aubervilliers Cedex, France.
Langmuir. 2018 Dec 18;34(50):15238-15244. doi: 10.1021/acs.langmuir.8b03206. Epub 2018 Nov 30.
Hydrogel coatings absorb water vapor, or other solvents, and, as such, are good candidates for antifog applications. In the present study, the transfer of vapor from the atmosphere to hydrogel thin films is measured in a situation where water vapor flows alongside the coating which is set to a temperature lower than the ambient temperature. The effect of the physico-chemistry of the hydrogel film on the swelling kinetics is particularly investigated. By using model thin films of surface-grafted polymer networks with controlled thickness, varied cross-links density, and varied affinity for water, we were able to determine the effect of the film hygroscopy on the dynamics of swelling of the film. These experimental results are accounted for by a diffusion-advection model that is supplemented with a boundary condition at the hydrogel surface: we show that the latter can be determined from the equilibrium sorption isotherms of the polymer films. Altogether, this paper offers a predictive tool for the swelling kinetics of any hydrophilic hydrogel thin film.
水凝胶涂层会吸收水蒸气或其他溶剂，因此非常适合用于防雾应用。在本研究中，当水蒸气沿着涂层流动，且涂层的温度低于环境温度时，测量了水蒸气从大气向水凝胶薄膜的传输情况。特别研究了水凝胶薄膜的物理化学性质对溶胀动力学的影响。通过使用具有受控厚度、不同交联密度和不同亲水性的表面接枝聚合物网络的模型薄膜，我们能够确定薄膜吸湿性对薄膜溶胀动力学的影响。这些实验结果通过一个扩散-对流模型来解释，该模型补充了水凝胶表面的边界条件：我们表明，可以根据聚合物薄膜的平衡吸附等温线来确定后者。总的来说，本文为任何亲水性水凝胶薄膜的溶胀动力学提供了一个预测工具。
