(606g) Small Angle X-Ray Scattering Determination of PS-b-PMMA Bulk Phase Diagram

As the demand for increased feature density grows in the semiconductor and microfabrication industry, the interest for thin film materials that can self-assemble into periodic features with a small spacing grows as well. Block copolymers (BCPs) have shown the ability to phase separate into line/space and cylindrical patterns with a feature spacing as low as 5 nm. The ordering of these features can be controlled by a chemical and/or topographic contrast in the substrate the films are cast on. Computer simulations are very useful in quickly weeding through many possible patterned substrates to determine their effect on the phase separated features. However to do this the model being used in the simulation must accurately represent the block copolymers. In this work the bulk phase diagram of a commonly used block copolymer (PS-b-PMMA) is generated in order to properly parameterize a coarse-grained molecular dynamics model such that the model can accurately reproduce the experimental phase diagram and then be used to explore the block copolymer. While PS-b-PMMA has been used as a standard for most BCP experiments, to the best of our knowledge, its phase diagram has never been published. The importance of the actual phase diagram cannot be understated, as it acts as a guide for the necessary properties a BCP requires to form the desired features. The bulk phase diagram for low dispersity block copolymers will be mapped out using small angle x-ray scattering.