%0 journal article
%@ 0024-9297
%A Lu, K.-Y.,Lo, T.-Y.,Georgopanos, P.,Avgeropoulos, A.,Shi, A.-C.,Ho, R.-M.

%D 2017
%J Macromolecules
%N 23
%P 9403-9410 
%R doi:10.1021/acs.macromol.7b02218
%T Orienting Silicon-Containing Block Copolymer Films with Perpendicular Cylinders via Entropy and Surface Plasma Treatment
%U https://doi.org/10.1021/acs.macromol.7b02218
23 
%X Controlling the orientation of nanostructured block copolymer (BCP) thin films is essential for next-generation lithography. However, obtaining BCP with perpendicular orientation remains a challenge because of the surface selectivity to the different blocks. This challenge is especially severe for silicon-containing BCPs which is notorious for its high surface energy difference between constituted blocks. Here, we demonstrate a new approach to achieve perpendicular orientation with high aspect ratio using a combination of architecture effect (entropy effect) and surface air plasma treatment (enthalpy effect). Specifically, perpendicular cylinders of star-block copolymers composed of polystyrene and poly(dimethylsiloxane) blocks can be formed from the bottom substrate to the top surface of the thin film.