Development of self-assembling block copolymer materials for emerging nanotechnologies requires an understanding of how surface energy and chemistry affect thin film phase behavior. Gradient methods provide an effective route to explore the role of surface energy/chemistry in thin film self-assembly. We have developed a single-step, vapor deposition method for fabricating two-component gradients in which cross-deposition of functionalized chlorosilanes under dynamic vacuum results in a linear change in monolayer composition across a silicon substrate. Gradients can be tailored for specific block copolymers by selecting chlorosilane functionalities that mimic the polymer molecular structure. Linear gradients were generated with functionalities suitable for PS-b-PMMA thin films and were characterized using x-ray photoelectron spectroscopy and contact angle measurements. We flow coated and annealed PS-b-PMMA thin films on the modified substrates. Optical and atomic force microscopy imaging revealed the expected changes in thin film surface morphology across the gradient, validating the utility of our setup.
Proceedings Title: Proceedings of the 240th ACS National Meeting
Conference Dates: August 22-26, 2010
Conference Location: Boston, MA
Conference Title: American Chemical Society Polymeric Materials Science and Engineering Division Preprints
Pub Type: Conferences
surface energy, combinatorial, gradients, block copolymer