Fluctuation Effects on Surface Pattern Formation in Thin Block Copolymer Films

Published

October 12, 2021

Author(s)

A C. Smith, Jack F. Douglas, Eric J. Amis, Alamgir Karim

Abstract

Hole formation on the surface of thin block copolymer films is investigated as a function of time (t), temperature (T) and film thickness. The size of the holes, h_s, approaches a steady state value at long times h_s,∞ = h_s(t -> ∞) and we introduce a simple kinetic model which gives a universal description of the kinetics of hole growth. The characteristic time, t, governing the rate of approach of hs to h_s,∞ is observed to first decrease upon heating and then to increase sharply as the estimated film disordering temperature, T_d, is approached from below. We also find a strong increase in h_s,∞ with increasing T. These observations suggest that fluctuations associated with the film disordering transition cause a slowing down of the equilibration of the film to its steady state and a reduction of the surface elasticity of the outer block copolymer layer. This large change in the surface properties of block copolymer films near T_d could have important ramifications for understanding transport property changes occurring in other amphiphilic films (e.g., lipid films comprising the membrane of cells) where non-monotonic mobility changes are observed near the respective disordering transition temperature.

Citation

Macromolecules

Pub Type

Journals

Keywords

block copolymer, combinatorial, ordering, thin film

Citation

Smith, A. , Douglas, J. , Amis, E. and Karim, A. (2021), Fluctuation Effects on Surface Pattern Formation in Thin Block Copolymer Films, Macromolecules (Accessed April 23, 2024)