Polystyrene鈥揚oly(ethylene oxide) Diblock Copolymer: The Effect of Polystyrene and Spreading Concentration at the Air/Water Interface

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• 作者：Cameron P. Glagola ; Lia M. Miceli ; Marissa A. Milchak ; Emily H. Halle ; Jennifer L. Logan
• 刊名：Langmuir
• 出版年：2012
• 出版时间：March 20, 2012
• 年：2012
• 卷：28
• 期：11
• 页码：5048-5058
• 全文大小：597K
• 年卷期：v.28,no.11(March 20, 2012)
• ISSN：1520-5827

文摘

Polystyrene-block-poly(ethylene oxide) (PS-PEO) is an amphiphilic diblock copolymer that undergoes microphase separation when spread at the air/water interface, forming nanosized domains. In this study, we investigate the impact of PS by examining a series of PS-PEO samples containing constant PEO (17鈥?00 g路mol^鈥?) and variable PS (from 3600 to 200鈥?00 g路mol^鈥?) through isothermal characterization and atomic force microscopy (AFM). The polymers separated into two categories: predominantly hydrophobic and predominantly hydrophilic with a weight percent of PEO of 20% providing the boundary between the two. AFM results indicated that predominantly hydrophilic PS-PEO forms dots while more hydrophobic samples yield a mixture of dots and spaghetti with continent-like structures appearing at 7% PEO or less. These structures reflect a blend of polymer spreading, entanglement, and vitrification as the solvent evaporates. Changing the spreading concentration provides insight into this process with higher concentrations representing earlier kinetic stages and lower concentrations demonstrating later ones. Comparison of isothermal results and AFM analysis shows how polymer behavior at the air/water interface correlates with the observed nanostructures. Understanding the impact of polymer composition and spreading concentration is significant in leading to greater control over the nanostructures obtained through PS-PEO self-assembly and their eventual application as polymer templates.