Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
Langmuir. 2010 Jan 19;26(2):1311-5. doi: 10.1021/la902483m.
We report the effect of increasing amounts of glycidyl methacrylate (GMA) in random copolymers of P(S-r-MMA-r-GMA) on the formation of nonpreferential mats for the assembly of P(S-b-MMA) block copolymers. Increasing the GMA concentration in the random copolymer from 1 (PG1) to 4 (PG4) mole % increased the cross-linking efficiency and reduced the effective minimum thickness of the cross-linked mat for perpendicular alignment of P(S-b-MMA) from approximately 6 nm to approximately 2 nm. The compositional window (so-called perpendicular window) of PG4 was defined for both symmetric and asymmetric P(S-b-MMA). Compared to PG1, incorporation of higher amount of polar comonomer (GMA) in PG4 shifted the perpendicular window toward higher styrene fraction as a result of the increased polarity. The defined perpendicular window for P(S-r-MMA-r-GMA) is equally applicable for random copolymers prepared by both controlled living and classical free-radical polymerizations.
我们报告了在 P(S-r-MMA-r-GMA)无规共聚物中增加甲基丙烯酸缩水甘油酯（GMA）的量对 P(S-b-MMA)嵌段共聚物组装形成非优先毡的影响。将无规共聚物中的 GMA 浓度从 1（PG1）增加到 4（PG4）摩尔%，增加了交联效率，并将垂直排列 P(S-b-MMA)的交联毡的有效最小厚度从大约 6nm 降低到大约 2nm。PG4 的组成窗口（所谓的垂直窗口）定义为对称和不对称 P(S-b-MMA)。与 PG1 相比，由于极性增加，在 PG4 中加入更多的极性单体（GMA）会将垂直窗口向更高的苯乙烯分数移动。为 P(S-r-MMA-r-GMA)定义的垂直窗口同样适用于通过控制活性和经典自由基聚合制备的无规共聚物。
