Wei Bin, Lam Peter G, Braunfeld Michael B, Agard David A, Genzer Jan, Spontak Richard J
Department of Chemical & Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA.
Langmuir. 2006 Oct 10;22(21):8642-5. doi: 10.1021/la061391j.
Incorporation of a block copolymer into a thin polymer film is observed to alter both the rate and mechanism by which the film dewets from an immiscible polymer substrate. Films with little or no copolymer dewet by classical nucleation and growth of circular holes, and the dewetting rate decreases with increasing copolymer concentration. Increasing the copolymer content at constant film thickness generates copolymer micelles that adsorb/aggregate along the polymer/polymer interface and promote nonclassical dewetting fluctuations similar in appearance to spinodal dewetting. At higher copolymer concentrations, dewetting proceeds after a lengthy induction period by the nucleation and growth of flower-shaped holes suggestive of film pinning or viscous fingering. Atomic force microscopy of the polymer/polymer interface after removal of the top film by selective dissolution reveals substantial structural development due to copolymer self-assembly.
人们观察到，将嵌段共聚物掺入聚合物薄膜中会改变薄膜从不混溶聚合物基材上脱湿的速率和机制。含少量或不含共聚物的薄膜通过经典的圆孔成核和生长进行脱湿，脱湿速率随共聚物浓度的增加而降低。在恒定薄膜厚度下增加共聚物含量会产生共聚物胶束，这些胶束沿聚合物/聚合物界面吸附/聚集，并促进外观上类似于旋节线脱湿的非经典脱湿波动。在较高的共聚物浓度下，脱湿在较长的诱导期后通过花形孔的成核和生长进行，这表明薄膜钉扎或粘性指进现象。通过选择性溶解去除顶层薄膜后，对聚合物/聚合物界面进行原子力显微镜观察，发现由于共聚物自组装，结构有显著发展。
