Collaborative Research: Liquid Crystal Anchoring and its Dependence on Interfacial Nano-Structure

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Non-Technical Abstract:The ubiquitous liquid crystal displays (LCDs), which form the core of flat panel computer displays, high definition TVs, and handheld electronic devices rely on the ability to control how the elongated liquid crystal (LC) molecules are oriented between the two glass plates (substrates) of the panel. One of the most common process used to control molecular orientation is to mechanically rub a polymer coated internal surface of the substrates. Over a period of three decades, this art has empirically evolved to the point of almost perfection. However, the microscopic mechanism that underlies the alignment of LC molecules still remains a mystery. This project is designed to systematically investigate the role of surface chemistry and nanoscale morphology in LC alignment. State-of-the-art experimental techniques such as high-resolution synchrotron x-ray reflectivity, atomic force microscopy, and fluorescence confocal microscopy will be employed to characterize the nature of aligning surfaces and methods to render them more effective. The results of this project will be extremely valuable to the science and technology of liquid crystals. Under this collaborative project, undergraduate and graduate students as well as postdoctoral scholars will be trained in the use of advanced experimental tools to address an important scientific problem. Outreach efforts involving local middle and high schools will be designed to incite enthusiasm for science among young pupil. The results of this study will be communicated to the scientific community and industry through peer publications.Technical Abstract:Nanoscale interfacial structure and surface energetics govern the behavior of a variety of phenomena as diverse as wetting, adhesion, and liquid crystal (LC) alignment. Good understanding of LC alignment on substrate surface is critical for their use in flat panel displays. A good understanding of LC-surface interactions and their relation to the chemical nature/structure has been seriously lacking. The main goal of the proposed research is to gain a good quantitative understanding of the role of interfacial nano-structure and the chemical nature of the interfaces and LCs at model organic and inorganic surfaces. This project will focus on surface driven phenomena that have their origins in the nanoscale organization at the interface of the organic material and the liquid crystal. Experimental techniques of high-resolution glancing incidence x-ray diffraction and reflectivity, fluorescence confocal microscopy, and electrooptical measurements will be employed to probe the nanoscale structure and structural transitions at the interfaces of interest. Under this collaborative project, undergraduate and graduate students as well as postdoctoral scholars will be trained in the use of advanced experimental tools to address an important problem. Outreach efforts involving local middle and high schools will be designed to incite enthusiasm for science among young pupil. The results of this study will be communicated to the scientific community and industry through peer publications.