Wang Chen-Hung, Chen Peilong, Lu C-Y David
Department of Physics and Center for Complex Systems, National Central University, Chungli 320, Taiwan.
Phys Rev E Stat Nonlin Soft Matter Phys. 2010 Jun;81(6 Pt 1):061501. doi: 10.1103/PhysRevE.81.061501. Epub 2010 Jun 16.
Phase-separation dynamics of polymer thin-film mixtures of polystyrene (PS) and poly(methyl methacrylate) (PMMA) are observed while an in-plane electric field is applied, instead of the out-of-plane fields usually employed previously. The phase separation is accompanied by the formation of PS dewetting holes at zero or weak fields. The dewetting velocity at 0.25 μm/min is a few times slower than that seen in regular bilayer dewetting. With the increasing of the field strength, we observe the formation of PS droplets in PMMA matrix, a reversal from zero- or low-field conditions. The PS dewetting holes are also suppressed. At further increased fields, PS droplets quickly penetrate up to the top of the PMMA matrix, leading to smaller and more irregular final PS droplets. This is manifested in the dramatic decrease in the growth exponent of the droplet size L from L∼t1.5 to L∼t0.1. These morphology changes are explained by the electrostatic energy resulted from the PS and PMMA dielectric contrast.
在施加面内电场而非先前通常使用的面外电场的情况下，观察到了聚苯乙烯（PS）和聚甲基丙烯酸甲酯（PMMA）聚合物薄膜混合物的相分离动力学。在零场或弱场下，相分离伴随着PS去湿孔的形成。0.25μm/min的去湿速度比常规双层去湿中的速度慢几倍。随着场强的增加，我们观察到在PMMA基体中形成了PS液滴，这与零场或低场条件下的情况相反。PS去湿孔也受到抑制。在进一步增加场强时，PS液滴迅速穿透到PMMA基体顶部，导致最终的PS液滴更小且更不规则。这表现为液滴尺寸L的生长指数从L∼t1.5急剧下降到L∼t0.1。这些形态变化是由PS和PMMA介电对比度产生的静电能所解释的。
