CNRS, Centre de Recherche Paul Pascal (CRPP), UPR 8641, F-33600 Pessac, France.
Centre de Recherche Paul Pascal, Université de Bordeaux , F-33600 Pessac, France.
Langmuir. 2017 May 23;33(20):4996-5005. doi: 10.1021/acs.langmuir.7b00473. Epub 2017 May 12.
Polymer coatings are commonly used to modify interfacial properties like wettability, lubrication, or biocompatibility. These properties are determined by the conformation of polymer molecules at the interface. Polyelectrolytes are convenient elementary bricks to build smart materials, given that polyion chain conformation is very sensitive to different environmental variables. Here we discuss the effect of an applied electric field on the properties of surfaces coated with poly(acrylic acid) brushes. By combining atomic force microscopy, quartz crystal microbalance, and contact angle experiments, we show that it is possible to precisely tune polyion chain conformation, surface adhesion, and surface wettability using very low applied voltages if the polymer grafting density and environmental conditions (pH and ionic strength) are properly formulated. Our results indicate that the effective ionization degree of the grafted weak polyacid can be finely controlled with the externally applied field, with important consequences for the macroscopic surface properties.
聚合物涂层通常用于改变润湿性、润滑性或生物相容性等界面特性。这些特性取决于聚合物分子在界面处的构象。鉴于聚离子链构象对不同环境变量非常敏感，聚电解质是构建智能材料的便捷基本构件。在这里，我们讨论了外加电场对涂有聚丙烯酸刷的表面性能的影响。通过原子力显微镜、石英晶体微天平以及接触角实验的组合，我们证明，如果适当设计聚合物接枝密度和环境条件（pH 值和离子强度），可以使用非常低的外加电压精确地调节聚离子链构象、表面附着力和表面润湿性。我们的结果表明，接枝弱聚酸的有效电离度可以通过外加电场进行精细控制，这对宏观表面性能有重要影响。
