Cross-sectional Imaging of Block Copolymer Thin Films on Chemically Patterned Surfaces

We have developed a method of using Ar ion milling and SEM to visualize the cross section of blockcopolymer films that were 50 nm thick. Directed assembly of lamellae-forming PS-b-PMMA on one-to-one and two-to-one chemical patterns was studied by both experiment and molecular simulation. The density multiplied PMMA domains were distorted and the PS domains had a 'U-shaped' structure on the substrate.