Kim Seyong, Yoo Misang, Baettig Julia, Kang Eun-Hye, Koo Jaseung, Choe Youngson, Choi Tae-Lim, Khan Anzar, Son Jeong Gon, Bang Joona
Department of Chemical and Biological Engineering, Korea University, Seoul 136-713, Republic of Korea.
Department of Materials, ETH-Zürich, CH-8093 Zürich, Switzerland.
ACS Macro Lett. 2015 Jan 20;4(1):133-137. doi: 10.1021/mz500761h. Epub 2015 Jan 8.
By introducing neutral star copolymers consisting of poly(styrene--methyl methacrylate) (PS--PMMA) arms, a perpendicular orientation of PS--PMMA microdomains in thin films could be achieved without any surface treatment. The star copolymers were synthesized by arm-first method in which short chain arms are cross-linked by employing a multifunctional coupling reagent via atom transfer radical polymerization. To find the optimal neutral composition for the perpendicular orientation, we varied the composition of MMA in PS--PMMA arms from 40 mol % to 80 mol %. It was found that the star copolymer having an overall PS and PMMA composition of 59:41 exhibits the well-ordered perpendicular orientation of lamellar structures after thermal annealing. Furthermore, we also prepared the deuterated star copolymers to trace them within PS--PMMA films along vertical direction by neutron reflectivity. In this case, it was observed that star copolymers were mainly located at the top surface and bottom interface of the films, thereby effectively neutralizing the surface/interfacial energy differences.
通过引入由聚（苯乙烯 - 甲基丙烯酸甲酯）（PS - PMMA）臂组成的中性星形共聚物，无需任何表面处理即可在薄膜中实现PS - PMMA微区的垂直取向。星形共聚物通过先臂法合成，其中短链臂通过原子转移自由基聚合使用多功能偶联剂进行交联。为了找到垂直取向的最佳中性组成，我们将PS - PMMA臂中MMA的组成从40摩尔％变化到80摩尔％。发现总体PS和PMMA组成为59:41的星形共聚物在热退火后表现出层状结构的有序垂直取向。此外，我们还制备了氘代星形共聚物，以便通过中子反射率沿垂直方向在PS - PMMA薄膜中追踪它们。在这种情况下，观察到星形共聚物主要位于薄膜的顶面和底部界面，从而有效地中和了表面/界面能差。
