Lower melting biaxial nematic liquid crystals based on ODBP

ORGN 610

Nicholas A. Zafiropoulos, nzafirop@email.unc.edu1, Louis A. Madsen, lmadsen@email.unc.edu2, Theo J Dingemans3, Wenbin Lin, wlin@unc.edu2, and Edward T. Samulski, et@unc.edu2. (1) Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, (2) Department of Chemistry, University of North Carolina, CB#3290, Chapel Hill, NC 27599, (3) Fundamentals of Advanced Materials Group, University of Delft, 2629 HS Delft, Netherlands
We have recently reported liquid crystal (LC) mesogens, ODBP-Ph-OC12 and ODBP-Ph-C7, based on a nonlinear 2,5-bis(p-hydroxyphenyl)-1,3,4-oxadiazole (ODBP) unit that exhibit biaxial nematic phases near 200°C. Biaxial nematics hold great potential for liquid crystal displays with novel switching modalities that could allow faster speeds and lower power consumption. These heterocyclic compounds are termed bent-core or boomerang-shaped calamitic mesogens because of their exocyclic bond angle of 134° in the mesogenic core. In our journey toward viable devices and stronger biaxial order, we have synthesized new derivatives of ODBP that possess lower nematic onset temperatures > 20°C in accompanying higher viscosities. Polarized optical microscopy and conoscopy indicate that these phases are indeed biaxial over a larger temperature range than previously reported. We have further quantified order properties of these materials using 2H NMR spectroscopy on static and rotating samples.
 

Materials, Devices, and Switches
8:00 AM-12:00 PM, Thursday, 30 March 2006 Georgia World Congress Center -- Georgia Ballroom 2, Oral

Division of Organic Chemistry

The 231st ACS National Meeting, Atlanta, GA, March 26-30, 2006