Temperature-dependent adsorption of pluronic F127 block copolymers onto carbon black particles dispersed in aqueous media
Temperature-dependent adsorption of pluronic F127 block copolymers onto carbon black particles dispersed in aqueous media
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DOI：
10.1021/jp014221i
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发表时间：
2002-10-24
影响因子：
3.3
通讯作者：
Alexandridis, P
中科院分区：
文献类型：
--
作者：
Lin, YN;Alexandridis, P
研究了聚氧化乙烯-聚氧化丙烯-聚氧化乙烯PEO-PPO-PEO嵌段共聚物Pluronic F127在水中分散的炭黑粒子上的吸附性能。根据小角中子散射（SANS）测量，CB颗粒具有分形结构。在低于嵌段共聚物临界胶束化浓度（CMC）时，CB颗粒对Pluronic F127的吸附行为符合Langmuir吸附等温线。温度在决定吸附层的厚度和结构方面起着重要的作用。在胶束开始形成的温度（CMT）以下，添加的Pluronic F127嵌段共聚物分子通过形成单层而有助于增加吸附层厚度（通过动态光散射测定）。在CMT之上，SANS实验，在对比度匹配条件下进行，其中使嵌段共聚物或CB颗粒"不可见"，证实吸附层具有与在不存在CB的情况下在水溶液中形成的Pluronic F127嵌段共聚物胶束类似的结构和尺寸。这项工作的目的之一是提供有关如何控制吸附层的厚度和结构（相应地，胶体稳定性）的信息，通过调整变量，如温度，嵌段共聚物的浓度，和/或溶剂的质量。
The adsorption properties of Pluronic F127 poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) PEO-PPO-PEO block copolymer onto carbon black (CB) particles dispersed in water have been investigated. The CB particles have fractal structure according to small-angle neutron scattering (SANS) measurements. The Langmuir isotherm could describe the adsorption behavior of Pluronic F127 onto CB particles below the block copolymer critical micellization concentration (CMC). Temperature plays an important role in determining the thickness and structure of the adsorbed layer. Below the temperature where micelles start forming (CMT), the added Pluronic F127 block copolymer molecules contribute to an increase of the adsorbed layer thickness (determined by dynamic light scattering) by forming a monolayer. Above the CMT, SANS experiments, performed under contrast matching conditions where either the block copolymer or the CB particles were rendered "invisible", confirmed that the adsorbed layer had structure and dimensions similar to these of Pluronic F127 block copolymer micelles that form in aqueous solution in the absence of CB. One of the aims of this work is to provide information on how to control the adsorbed layer thickness and structure (and correspondingly, colloidal stability) by tuning variables such as temperature, block copolymer concentration, and/or solvent quality.