Spontaneous bilayer phase separations of spin-coated polymer blend thin films: A neutron reflectivity study

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• 作者：Jaseung Koo ; Sushil Satija ; Jeong-Soo Lee ; Young-Soo Seo
• 关键词：polymer blend thin films ; neutron reflectivity ; binary phase separation ; spin coating
• 刊名：Macromolecular Research
• 出版年：2016
• 出版时间：December 2016
• 年：2016
• 卷：24
• 期：12
• 页码：1105-1110
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Polymer Sciences; Soft and Granular Matter, Complex Fluids and Microfluidics; Physical Chemistry; Characterization and Evaluation of Materials; Nanochemistry; Nanotechnology;
• 出版者：The Polymer Society of Korea
• ISSN：2092-7673
• 卷排序：24

文摘

This study investigates the spontaneous formation of phase-separated bilayer structures of polymer blend thin films upon spin coating. Neutron reflectivity is used to measure the bilayer structure of deuterated polystyrene (dPS) and polymethylmethacrylate (PMMA) blend thin films with various molecular weights (M_w). The results indicate that the binary polymer blend forms a well-defined phase-separated bilayer structure of a dPS-rich layer on top of a PMMA rich layer with clear interfaces between the layers. The interfacial width is in reasonable agreement with the results of self-consistent field theory modified to account for capillary waves. The blend with higher M_w exhibits broader interfaces than the theoretical predictions, probably due to the reduced mobility of mixed polymers in the solvent during spin coating. Formation of thin blend films with parallel phase separation can provide a viable route to potential applications of the active layer in bilayer heterojunction devices for polymer photovoltaic applications.