The ubiquitous utilization of integrated circuits shows that industry is exceptionally capable of manufacturing ultra-high resolution arrangements of semiconductors, metals and insulators. However, there is a vast disconnect between the methods for patterning these sorts of hard materials and those that exist for patterning soft materials such as chemicals, polymers or biological materials. If it were possible to pattern soft materials with the same reliability and resolution as hard materials, it would enable the manufacture of myriad structures and devices including electronics with multiplexed biosensor arrays or nanoscale organic electronic devices for applications in stretchable electronics. While additive manufacturing strategies are very useful at the macroscopic scale, these approaches have not achieved manufacturing-level reproducibility when patterning soft materials at the nanoscale. This award will enable nanoscale manufacturing of soft materials by providing the tools and understanding needed to realize patterning with industry-required reliably and nanoscale resolution. This interdisciplinary work spans fluid mechanics, control theory, and nanoscience and contributes to the undergraduate and graduate level education of engineering students. Furthermore, this work provides opportunities for students from broad backgrounds to design and interact with materials at previously inaccessible scales.
The main goal of this research work is to develop the fundamental and technological foundation to transition tip-based nanopatterning of soft materials into a manufacturing tool. This approach is based on the transfer of material from an ink-coated scanning probe to a surface. Despite over a decade of research, reproducibility and controllability have remained key barriers for the adoption of this technique in a manufacturing setting. This research work addresses a number of processing issues that have not previously received attention. It investigates and develops novel approaches, e.g., a method for precisely monitoring the quantity of ink that is on a probe, an ink formulation that allows one to pattern and image with the same probe, and a procedure for monitoring and controlling the concentration of reagents in the ink during patterning. Equally important, these studies are designed to provide deeper insight into the patterning process and answer open questions about nanoscale capillarity and statistical mechanics in systems that violate the continuum hypothesis. Additionally, these new approaches are combined with advanced models of patterning to form an automated closed-loop feedback system that iteratively improves the quality of patterning in situ.
