Combinatorial mapping of the phase behavior of ABC triblock terpolymers in thin films: Experiments

We report on the thin film phase behavior of poly(styrene)-block-poly(2-vinylpyridine)-block-poly(tert-butyl methacrylate) triblock terpolymers with volume fractions phi(PS):phi(P2VP):phi(PtBMA) scaling as 1:12 x, with x ranging from 3.05 to 4. On controlled annealing in the vapor of a nearly nonselective solvent the films form terraces of well-defined thickness with a highly ordered hexagonally perforated lamella structure. Using a gradient combinatorial technique we are able to systematically map the dependence of the morphology on the film thickness. By use of substrates with different surface energy we demonstrate that the perforated lamella is a stable phase, regardless of the chemical nature of the substrate, which makes the structure and methodology robust for application in nanotechnology.