Department of Chemistry , University of Michigan , 930 North University Avenue , Ann Arbor , Michigan 48109 , United States.
Department of Chemical Engineering , Massachusetts Institute of Technology , 77 Massachusetts Avenue , Cambridge , Massachusetts 02139 , United States.
Langmuir. 2019 Oct 15;35(41):13292-13300. doi: 10.1021/acs.langmuir.9b02544. Epub 2019 Oct 4.
A hydrogel is a hydrophilic cross-linked polymer network which can contain a large amount of water. Hydrogels with distinguished interfacial physical toughness were analyzed for their potential application as antifouling coating materials, utilizing sum frequency generation (SFG) spectroscopy as the interfacial analytical technique. The surface structures of one sulfobetaine (SBMA) zwitterionic hydrogel (ZWHG) and two polysaccharide hydrogels (PHGs) were probed in air; their interfacial structures with silica were examined using SFG in water and protein solutions, respectively. Both ZWHG and PHGs interfaces in water were dominated by strongly hydrogen-bonded water molecules, but the bonding strength associated with ZWHG was much stronger. Although all hydrogels experienced interfacial change in the presence of protein solutions, after cleaning, the zwitterionic hydrogel interface recovered almost completely while the other two hydrogels were subject to irreversible protein adsorption. Additionally, orientational analysis of ZWHG methyl groups in water was conducted and related to the superior hydrogen-bonding strength of water molecules at the ZWHG interface. The interfacial structures of hydrogel materials probed by SFG can be correlated to their antifouling properties. This research highlighted the critical role that hydrogen-bonding strength of interfacial water molecules play for antifouling applications.
水凝胶是一种亲水性的交联聚合物网络，可以包含大量的水。具有显著界面物理韧性的水凝胶被分析其作为防污涂层材料的潜在应用，利用和频发生（SFG）光谱作为界面分析技术。在空气中探测了一种磺酸甜菜碱（SBMA）两性离子水凝胶（ZWHG）和两种多糖水凝胶（PHGs）的表面结构；分别在水中和蛋白质溶液中使用 SFG 研究了它们与二氧化硅的界面结构。在水中，ZWHG 和 PHGs 界面都由强氢键水分子主导，但 ZWHG 相关的键合强度要强得多。尽管所有水凝胶在蛋白质溶液存在下都经历了界面变化，但在清洗后，两性离子水凝胶界面几乎完全恢复，而其他两种水凝胶则发生了不可逆的蛋白质吸附。此外，还对水相中 ZWHG 甲基的取向进行了分析，并将其与 ZWHG 界面水分子的氢键强度相关联。通过 SFG 探测的水凝胶材料的界面结构与其防污性能相关。这项研究强调了界面水分子氢键强度在防污应用中的关键作用。
