Large-Area Accurate Position Registry of Microparticles on Flexible, Stretchable Substrates Using Elastomer Templates

This work introduces a robust means for excellent position registry of microparticles via a forced assembly technique on flexible or stretchable substrates. It is based on the dry powder rubbing process which allows assembly of a microparticle monolayer in a short time without requiring any solvent or thermal treatment. Elastic physical templates are used as substrates for the forced assembly in this study. Since the elastic templates can reduce the stress accumulation between the closely packed particles, they can minimize the defect formation in the particle assembly in large areas. The method can be used with powders comprising irregularly shaped particles with a relatively large size distribution that cannot be periodically ordered by conventional self-assembly. Furthermore, a non-closely packed particle array can be fabricated readily in large area, which is highly desirable for practical uses of the particle monolayers. The particle monolayers formed on the elastomer templates can be transferred to surfaces coated with thermoplastic block copolymers. Once transferred, the particle monolayers are flexible and stretchable over their entire surface. This work uses the particle monolayers on a large-area flexible substrate as photomasks to produce various photoresist patterns.