TECHNICAL ABSTRACTS Monday, PM Session Chair
3:45 PM – 4:15 PM
Technical Session 5 3:45 PM – 5:45 PM Room 410 Nanotechnology Applications I Kwame Owusu‐Adom Department of Chemical and Biomedical Engineering, University of Iowa Presenters Highlighted Speaker “Polymer/LC Dynamic Gratings”
Timothy J. Bunning Air Force Research Lab, MLPJ, WPAFB, OH Abstract Nano‐sized polymer‐dispersed liquid crystal (PDLC) systems (<100 nm diameter) have distinct advantages in a number of applications due to a minimization of light scattering and an increase in switching speed. The key to formation is the proper photochemistry which will restrict droplet growth and coalescence due to fast gelation of the growing polymer network. We present some examples of 0‐D, 1‐D, 2‐D, and 3‐D ordered systems. Multidimensional ordering is done by holographic photopolymerization using two or more interfering laser beams. Using 2‐beam holography, simple switchable transmission and reflection diffraction gratings can be formed. More importantly, the diffractive properties of the system can be modulated in a gray‐scale mode using an applied electric field. We also report the recording of holographic polymer‐dispersed liquid crystal reflection gratings while applying a shear stress parallel to the film plane. High diffraction efficiency for light polarized in a direction parallel to the stress is obtained with nearly zero diffraction efficiency for the perpendicular polarization. Contrary to post‐recording stress‐induced polarization sensitization, the in situ process results in permanently polarized gratings. 116