Poly(dimethylsiloxane-<i>b</i>-methyl methacrylate): A Promising Candidate for Sub-10 nm Patterning

Abstract

We report herein the modular synthesis and nanolithographic potential of poly(dimethylsiloxane- block -methyl methacrylate) (PDMS- b -PMMA) with self-assembled domains approaching sub-10 nm periods. A straightforward and modular coupling strategy, optimized for low molecular weight diblocks and using copper-catalyzed azide–alkyne “click” cycloaddition, was employed to obtain a library of PDMS- b -PMMA and poly(dimethylsiloxane- block -styrene) (PDMS- b -PS) diblock copolymers. Flory–Huggins interaction parameters, determined from small-angle X-ray scattering experiments, were high for PDMS- b -PMMA (χ ∼ 0.2 at 150 °C), suggesting this diblock copolymer system has promise for sub-10 nm lithographic applications when compared to the corresponding PDMS- b -PS diblock copolymers (χ ∼ 0.1 at 150 °C). Performance evaluation in thin film self-assembly experiments allowed domain periods as small as 12.1 nm to be obtained, which is among the smallest highly ordered nanoscale patterns reported hitherto for thermally annealed materials.