Coatings of Polyethylene Glycol for Suppressing Adhesion between Solid Microspheres and Flat Surfaces
Coatings of Polyethylene Glycol for Suppressing Adhesion between Solid Microspheres and Flat Surfaces
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DOI：
10.1021/la300545v
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发表时间：
2012-03-20
期刊：
影响因子：
3.9
通讯作者：
Vullev, Valentine I.
中科院分区：
文献类型：
--
作者：
Upadhyayula, Srigokul;Quinata, Timothy;Vullev, Valentine I.
本文介绍了抑制玻璃表面和聚合物微球之间粘附的表面涂层的开发和检查。超顺磁性掺杂允许在微珠上施加磁力。聚合物的羧基官能化提供了用具有不同分子量的聚乙二醇（PEG）包覆珠粒的手段。在重力作用下，微珠沉积在具有类似聚合物涂层的玻璃表面上。我们通过施加类似于1.2pN的拉力来检查从玻璃表面去除珠粒的功效。在施加拉力约5秒后，表面上剩余的珠百分比用作粘附倾向的指示。具有3至10 kDa分子量范围的PEG涂层对于抑制粘附是必不可少的。对于我们使用的特定基底、表面化学和水性介质，5 kDa的涂层表现出对粘附的最佳抑制：也就是说，在施加拉力磁力后，只有3%的微珠保留在表面上。当玻璃或珠未被PEG化时，它们之间的粘附是显著的。添加不带电的表面活性剂，THEX，高于其临界胶束浓度（CMC）抑制非涂层基板之间的粘附力。然而，这种表面活性剂诱导的粘附抑制的改善的程度没有超过我们通过PEG化两种基材获得的防止粘附的质量。此外，使用表面活性剂并没有显着改善抑制珠表面粘附时，两个基板聚乙二醇化。这些研究结果表明，这样的表面活性剂添加剂往往是多余的，共价接枝涂层的PEG与选定的链长提供足够的抑制非特异性界面相互作用。
This article describes the development and the examination of surface coatings that suppress the adhesion between glass surfaces and polymer microspheres. Superparamagnetic doping allowed for exerting magnetic forces on the microbeads. The carboxyl functionalization of the polymer provided the means for coating the beads with polyethylene glycol (PEG) with different molecular weight. Under gravitational force, the microbeads settled on glass surfaces with similar polymer coatings. We examined the efficacy of removing the beads from the glass surfaces by applying a pulling force of similar to 1.2 pN. The percent beads remaining on the surface after applying the pulling force for approximately 5 s served as an indication of the adhesion propensity. Coating of PEG with molecular weight ranging between 3 and 10 kDa was essential for suppressing the adhesion. For the particular substrates, surface chemistry and aqueous media we used, coatings of 5 kDa manifested optimal suppression of adhesion: that is, only 3% of the microbeads remained on the surface after applying the pulling magnetic force. When either the glass or the beads were not PEGylated, the adhesion between them was substantial. Addition of a noncharged surfactant, TWEEN, above its critical micelle concentrations (CMCs) suppressed the adhesion between noncoated substrates. The extent of this surfactant-induced improvement of the adhesion suppression, however, did not exceed the quality of preventing the adhesion that we attained by PEGylating both substrates. In addition, the use of surfactants did not significantly improve the suppression of bead-surface adhesion when both substrates were PEGylated. These findings suggest that such surfactant additives tend to be redundant and that covalently grafted coatings of PEGs with selected chain lengths provide sufficient suppression of nonspecific interfacial interactions.