Adsorption of Polyether Block Copolymers at Silica鈥揥ater and Silica鈥揈thylammonium Nitrate Interfaces

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• 作者：Zhengfei Chen ; Yumi Kobayashi ; Grant B. Webber ; Kazuhide Ueno ; Masayoshi Watanabe ; Gregory G. Warr ; Rob Atkin
• 刊名：Langmuir
• 出版年：2015
• 出版时间：June 30, 2015
• 年：2015
• 卷：31
• 期：25
• 页码：7025-7031
• 全文大小：373K
• ISSN：1520-5827

文摘

Atomic force microscope (AFM) force curves and images are used to characterize the adsorbed layer structure formed by a series of diblock copolymers with solvophilic poly(ethylene oxide) (PEO) and solvophobic poly(ethyl glycidyl ether) (PEGE) blocks at silica鈥搘ater and silica鈥揺thylammoniun nitrate (EAN, a room temperature ionic liquid (IL)) interfaces. The diblock polyethers examined are EGE₁₀₉EO₅₄, EGE₁₁₃EO₁₁₅, and EGE₁₀₄EO₁₇₈. These experiments reveal how adsorbed layer structure varies as the length of the EO block varies while the EGE block length is kept approximately constant; water is a better solvent for PEO than EAN, so higher curvature structures are found at the interface of silica with water than with EAN. At silica鈥搘ater interfaces, EGE₁₀₉EO₅₄ forms a bilayer and EGE₁₁₃EO₁₁₅ forms elongated aggregates, while a well-ordered array of spheres is present for EGE₁₀₄EO₁₇₈. EGE₁₀₉EO₅₄ does not adsorb at the silica鈥揈AN interface because the EO chain is too short to compete with the ethylammonium cation for surface adsorption sites. However, EGE₁₁₃EO₁₁₅ and EGE₁₀₄EO₁₇₈ do adsorb and form a bilayer and elongated aggregates, respectively.