Ph.D. University of Hull (UK), 1995
Research is primarily concerned with the synthesis of advanced liquid-crystalline materials for all-optical applications including for example, ferroelectric displays and optical interconnects for telecommunications transmission. The work is highly interdisciplinary and involves a unique blend of new methodology development targeted toward the synthesis of advanced liquid crystals and evaluation of the physical characteristics of the resulting mesogens (polarized optical microscopy, differential scanning calorimetry and electrooptic studies). A number of current projects are described in the following text:
De novo construction of new alkoxythiophene building blocks for liquid crystal synthesis. A prominent area of our research involves the synthesis of the elusive alkoxythiophene unit. Although this unit is a simple heterocycle, synthetic methodologies leading to the construction of these units are rare, low yielding, and often hazardous. We have developed a highly efficient synthesis of flexible alkoxythiophene units that are ideal precursors for the synthesis of thermotropic liquid crystals. Ring closure of appropriately substituted Î²-keto esters using Lawesson's reagent has been effected in both solvent-based and solvent free conditions (using microwave irradiation). We are currently using this chemistry in the synthesis of ferroelectric dopant and host materials for use in the latest portable, low-power display devices.
Construction of fluorinated thiophene units from fluorinated acyclic precursors. In collaboration with Paul Sampson's group we have been exploring the synthesis of fluorothiophenes from acyclic fluorinated dicarbonyl compounds. This chemistry represents the first potential pathway to fluorothiophenes using ring-closing methodology. The unique characteristics of low viscosity and high polarity of the fluorothiophene ring make these units ideal candidates for incorporation into calamitic structures with large negative dielectric anisotropy. Liquid crystals incorporating these units have been recently reported by our group and are some of the fastest ferroelectrics ever observed.
High birefringence materials for beam-steering applications. We have been involved in collaboration with Prof. S. T. Wu (University of Central Florida) for a number of years. We are concerned with the synthesis of materials having birefringences of over 0.5 and are particularly interested in compact mesogenic materials that contain highly polarizable elements. Our current focus is the synthesis of new hetereocylic units with unusual levels of conjugation.
Synthesis and evaluation of high chirality materials for use as asymmetric dopants in chiral nematic (cholesteric) display devices. Currently we are collaborating with Kent Displays Incorporated on the synthesis of new materials that are capable of conferring an extraordinarily high twisting power when placed in nematic host mixtures. We have received two NSF STTR grants and have submitted a full patent detailing the synthesis of such a material that is soluble, extremely robust, has a high twisting power (HTP), and confers a HTP that is constant over a wide operating temperature range!