(380f) Particle Crystallinity in Automated Langmuir-Blodgett Deposition: Effect of Speed and Concentration

The promise of scalable nanomanufacturing is to translate the ability to create nanoscale functionality, often in the form of 3D nanostructures, to processes that provide industrial-scale qualtities of material. Few efforts have succeeded in this effort. In the laboratory, colloidal crystals have long been used as templates for well-ordered structures enabling control of mass, heat, photon, and electron transport at the nanoscale. Automated Langmuir-Blodgett (ALB) roll-to-roll coating of particles into well-ordered monolayers that can be used to fabricate colloidal crystals. Previous work has characterized the process parameters with regard to coating speed and general coating morphology. This work directly measures the crystallinity of micron-scale microsphere coatings and correlates their structure back to the process parameters, primarily coating speed, mass delivery rate, and underflow recirculation rate. In addition, the forumlation of the suspension in the addition of nanoparticles much smaller than the coated particles is altered based on observation of coating enhancement in laboratory scale convective deposition. Overall, slower speed coatings and the addition of nanoparticles roughly 10:1 in radius to the microspheres tends to increase the crystallinity of the colloidal microstructure. The relationship of process parameters to structure are somewhat clear, however the role of nanoparticles in enhancing crystallization is confusing because only a small fraction of nanoparticles from suspension are translated to the final coating.