Internal Interface of a Compressed PEE−PEO Diblock Copolymer Monolayer
Internal Interface of a Compressed PEE−PEO Diblock Copolymer Monolayer
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压缩 PEE−PEO 二嵌段共聚物单层的内部界面
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
C. Helm
中科院分区：
文献类型：
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作者：
Alexander Wesemann;H. Ahrens;R. Steitz;A. Förster;C. Helm
由流体疏水性（聚（乙基乙烯），PEE）和亲水性（聚（环氧乙烷），PEO）嵌段组成的两亲性嵌段共聚物在空气/水界面处形成单层。利用X射线和中子反射率，研究了PEE 432 − PEO 484的密度分布。结果发现，聚合物吸附层由均匀的PEE和增溶的PEO块组成，其可以横向压缩3倍。PEE厚度与分子面积成反比地增加，并且PEO刷遵循良溶剂中的刷所预测的标度律。然而，两个嵌段的拉伸使PEE-PEO界面变粗糙，导致从吸附到疏水界面（0.8 - 1.1 nm厚）的PEO单层转变为3 nm厚的PEE-PEO/水界面层。界面层的这种转变突出了两亲性嵌段共聚物的富相行为，这类似于脂质和非离子表面活性剂的富相行为。
Amphiphilic block copolymers consisting of a fluid hydrophobic (poly(ethyl ethylene), PEE) and a hydrophilic (poly(ethylene oxide), PEO) block form monolayers at the air/water interface. With X-ray and neutron reflectivity, the density profile of PEE432−PEO484 was investigated. It was found that the polymer adsorption layer consists of a homogeneous PEE and a solubilized PEO block, which can be laterally compressed by a factor of 3. The PEE thickness increases in inverse proportion to the molecular area, and the PEO brush follows the scaling law predicted for a brush in a good solvent. However, the stretching of the two blocks roughens the PEE−PEO interface, causing a transition from a PEO monolayer adsorbed to a hydrophobic interface (0.8−1.1 nm thick) to a PEE−PEO/water interfacial layer of 3 nm thickness. This transition of the interfacial layer highlights the rich phase behavior of amphiphilic block copolymers, which resembles that of lipids and nonionic surfactants.