Department of Electrical and Computer Engineering, National University of Singapore, 21 Lower Kent Ridge Road, Singapore 117576, Republic of Singapore.
Sci Rep. 2012;2:617. doi: 10.1038/srep00617. Epub 2012 Aug 31.
Self-assembly of block copolymers has been identified as a potential candidate for high density fabrication of nanostructures. However, the factors affecting its reliability and reproducibility as a patterning technique on various kinds of surfaces are not well-established. Studies pertaining to block copolymer self-assembly have been confined to ultra-flat substrates without taking into consideration the effect of surface roughness. Here, we show that a slight change in the angstrom-scale roughness arising from the surface of a material creates a profound effect on the self-assembly of polystyrene-polydimethylsiloxane block copolymer. Its self-assembly was found to be dependent on both the root mean square roughness (R(rms)) of the surface and the type of solvent annealing system used. It was observed that surface with R(rms)< 5.0 Å showed self-assembly. Above this value, the kinetic hindrance posed by the surface roughness on the block copolymer leads to its conforming to the surface without observable phase separation.
嵌段共聚物的自组装已被确定为在各种表面上进行高密度纳米结构制造的潜在候选方法。然而，作为一种图案化技术，影响其可靠性和可重复性的因素尚未得到很好的确立。关于嵌段共聚物自组装的研究仅限于超平坦的基底，而没有考虑表面粗糙度的影响。在这里，我们表明，材料表面上的埃级粗糙度的微小变化会对聚苯乙烯-聚二甲基硅氧烷嵌段共聚物的自组装产生深远的影响。发现其自组装既依赖于表面的均方根粗糙度（R(rms)），也依赖于所用溶剂退火系统的类型。观察到 R(rms)<5.0 Å 的表面表现出自组装。在这个值以上，表面粗糙度对嵌段共聚物的动力学阻碍导致其顺应表面而没有可观察到的相分离。
