Gradient Solvent Vapor Annealing of Block Copolymer Thin Films Using a Microfluidic Mixing Device
Kathryn L. Beers, Michael J. Fasolka, Julie N. Albert, Timothy D. Bogart, Ronald L. Lewis, J. Brian Hutchison, Bryan D. Vogt, Thomas H. Epps
Solvent vapor annealing (SVA) with solvent mixtures is a promising approach for controlling block copolymer thin film self-assembly. In this work, we present the design and fabrication of a solvent-resistant microfluidic mixing device to produce discrete SVA gradients in solvent composition and/or total solvent concentration. Using the device, we identified solvent composition dependent morphology transformations in poly(styrene-b-isoprene-b-styrene) films. This device enables faster and more robust exploration of SVA parameter space, providing insight into self-assembly phenomena.