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The goal of the proposed research is to investigate a new concept for preparing multi-component organic thin films with engineered molecular-scale organization and composition using liquid crystal (LC)-based inks combined with patterned anchoring alignment stamps. The central idea is to couple molecular order and composition in a multicomponent self-assembled monolayer (SAM) deposited from a nematic ink to a pattern on a stamp through an elastic strain field produced by competitive LC anchoring at the stamp- and SAM surfaces. The concept resembles strained heteroepitaxial growth at a solid-solid interface, except that the strain field is provided by a nematic LC, rather than the substrate, and results from anchoring and elastic forces, rather than an epitaxial mismatch. Despite the fact that LC elastic constants are much weaker than those of most solids, by selecting systems with an appropriate balance of energies we show how the LC can nevertheless have a significant influence, while affording considerable flexibility in structural and compositional control.The research is motivated by both fundamental interests and the practical importance of developing alternative approaches for creating chemically functionalized surfaces with designer architectures at nanometre to micron length scales. In addition to furthering our basic understanding of LC-surface interactions, phase behaviour, and pattern formation in organic thin films, the techniques to be developed in this work represent a step toward preparing materials with tailored physical and chemical properties, potentially useful for applications ranging from controlled wetting and adhesion, to chemical sensing and LC display technology.The concepts we propose to investigate represent a fundamentally new approach for using macroscopic influences to harness and control self-assembly at the molecular-scale, drawing upon ideas from LC science and multiphase systems. To carry out the work, an interdisciplinary collaboration is proposed between Prof. David Patrick, the Visiting Fellow and expert in LCs and LC-surface interactions, and Dr. Stuart Clarke, an expert in multiphase systems and the physical chemistry of organic thin films. Dr. Patrick, who is a Professor of Chemistry and Director of the Advanced Materials Science and Engineering Centre at Western Washington University, is a pioneer in unconventional uses of thermotropic LC solvents to prepare organized materials, while Clarke's group at Cambridge specialises in the molecular-scale properties of multi-component and multi-phase systems. The collaboration will combine these two areas of study.While at Cambridge, the Visiting Fellow will interact with other groups in the Chemistry Department and BP Institute, as well as those at several other universities across the UK, who will benefit from the expertise he brings in these novel approaches. Longer term, the proposed research will lay the foundations for a sustained collaboration that can continue after Patrick returns to his home institution.The proposed experimental programme would produce a comprehensive picture of the relationships between film composition and structural properties, LC forces, and the thermodynamics of monolayer formation in self-assembled monolayers deposited using LC inks. Although great deal of attention has been given to understanding the influence surfaces exert on LCs, including surfaces decorated with SAMs, the reverse situation-that is, LCs influencing surfaces-has hardly been considered at all. Taken together, the results of these experiments should provide a definitive assessment of the feasibility of LC-based inks, while deepening our understanding of the scientifically interesting and technologically important underlying phenomena.
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