ENGINEERING RESEARCH EQUIPMENT: Differential Scanning Calorimeter for Liquid Crystal Research

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CTS-9411604 Chen Equipment funds are requested for the procurement of a Perkin Elmer DSC-7 differential scanning calorimeter to help initiate a project on low molar mass glass-forming liquid crystals. It should be noted that both single crystals and liquid crystals have found numerous potential applications in optical and laser systems. Whereas single crystals are difficult to process, liquid crystal devices lack environmental durability. To overcome these problems, liquid crystalline polymers capable of vitrificaton have been explored in recent years. However, the highly viscous nature of polymeric materials has presented a processing problem where device uniformity is critical. Hence, ideal materials should possess low melt viscosity besides requisite optical characteristics. Few low molar mass liquid crystals capable of vitrification with glass transition temperature above the ambient have been reported to date. Furthermore, there is little understanding of glass-forming liquid crystals from the perspective of chemical structure. It is proposed that two seemingly opposing structural features, a mesogenic core and a volume-excluding moiety, be chemically bonded to each other via a flexible spacer. To strike a subtle balance between the types of mesogenic core and volume-excluding moiety, the number of mesogenic cores per volume excluding moiety, and the flexible spacer length is the key to accomplishing liquid crystal mesomorphism and glass formation in a single molecular entity. Representative structures have been proposed for synthesis and characterization, and molecular simulation will subsequently be performed to furnish new insights into glass formation and liquid crystal mesomorphism by organic molecules. Other on-going projects on high birefringence nematic polymers, hydrogels, and cycloaliphatic polymers for eye wear and optical systems applications will also benefit from the DSC system to be acquired. ***