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arXiv · 1109.0833

Block Copolymer Films with Free Interfaces: Ordering by Nano-Patterned Substrates

Xingkun Man·David Andelman·Henri Orland
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Abstract

We study block copolymers (BCP) on patterned substrates, where the top polymer film surface is not constrained but is a free interface that adapts its shape self-consistently. In particular, we investigate the combined effect of the free interface undulations with the wetting of the BCP film as induced by nano-patterned substrates. For a finite volume of BCP material, we find equilibrium droplets composed of coexisting perpendicular and parallel lamellar domains. The self-assembly of BCP on topographic patterned substrates was also investigated and it was found that the free interface induces mixed morphologies of parallel and perpendicular domains coupled with a non-flat free interface. In both cases, the free interface relaxes the strong constraints that would otherwise be imposed by a fixed top boundary (which is commonly used in simulations), and affects strongly the BCP ordering. Our study has some interesting consequences for experimental setups of graphoepitaxy and nanoimprint lithography.

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Xingkun Man, David Andelman, Henri Orland. 2012-07-05. Block Copolymer Films with Free Interfaces: Ordering by Nano-Patterned Substrates. https://doi.org/10.1103/physreve.86.010801

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