Department of Chemistry, Surface and Corrosion Science, Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
J Colloid Interface Sci. 2010 Aug 1;348(1):189-97. doi: 10.1016/j.jcis.2010.03.067. Epub 2010 Apr 3.
Adsorption properties of bottle-brush polyelectrolytes have been investigated using dual polarization interferometry (DPI), which provides real time monitoring of adsorbed layer thickness and refractive index. The adsorption on silicon oxynitride was carried out from aqueous solution with no added inorganic salt, and the adsorbed polyelectrolyte layer was subsequently rinsed with NaCl solutions of increasing concentration. The bottle-brush polyelectrolytes investigated in this study have different ratios of permanent cationic charged segments and uncharged PEO side chains. Both the cationic groups and the PEO side chains have affinity for silica-like surfaces, and thus contribute to the adsorption process that becomes rather complex. Adsorption properties in water, responses to changes in ionic strength of the surrounding medium, adsorption kinetics and the layer structure are all strongly dependent on the ratio between backbone charges and side chains. The results are interpreted in terms of competitive adsorption of segments with different chemical nature. The adsorption kinetics is relatively fast, taking only tens to hundreds of seconds when adsorbed from dilute 100 ppm solutions. The DPI technique was found to be suitable for studying such rapid adsorption processes, including determination of the initial adsorption kinetics. We expect that the effects observed in this study are of general importance for synthetic and biological polymers carrying segments of different nature.
使用双折射干涉测量法（DPI）研究了梳型聚电解质的吸附特性，该方法可实时监测吸附层厚度和折射率。在没有添加无机盐的情况下，从水溶液中进行了硅氧氮化物的吸附，随后用浓度逐渐增加的 NaCl 溶液冲洗吸附的聚电解质层。本研究中研究的梳型聚电解质具有不同比例的永久阳离子带电段和不带电的 PEO 侧链。阳离子基团和 PEO 侧链都与类似硅的表面有亲和力，因此有助于吸附过程变得相当复杂。在水中的吸附特性、对周围介质离子强度变化的响应、吸附动力学和层结构都强烈依赖于主链电荷与侧链之间的比例。结果根据不同化学性质的片段的竞争吸附来解释。吸附动力学相当快，从稀 100ppm 溶液中吸附时仅需数十到数百秒。发现 DPI 技术适用于研究这种快速吸附过程，包括确定初始吸附动力学。我们预计，在本研究中观察到的影响对于携带不同性质片段的合成和生物聚合物具有普遍重要性。
