25 July 1989 Thermodynamics of the Electric Field Induced Orientation of Nematic Droplet/Polymer Films
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Films consisting of micron-sized nematic liquid crystal droplets dispersed in a polymer matrix (NCAP) represent an important new class of electro-optical devices. These films strongly scatter light in the tm powered state, but achieve a high degree of clarity when an electric field is applied. In this report we describe the aspects of liquid crystal and polymer composition that control the magnitude of the electric field required to orient the nematic droplets. The droplet shape is found to be an important factor in the electro-optical response of these films. In films deposited from aqueous solutions the nematic cavities in the film are usually oblate in nature, with the short axis perpendicular to the film plane. The nematic, which adopts a bipolar configuration within the cavity, is preferentially aligned so that each droplet's symmetry axis is aligned parallel to the film plane in the rest state, but rotates to lie parallel with the field in the powered state. Capacitance data is presented which supports this picture. It is shown that the nematic droplet shape can be a major factor in determining the thermodynamics of droplet orientation.
© (1989) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Paul S. Drzaic, Paul S. Drzaic, } "Thermodynamics of the Electric Field Induced Orientation of Nematic Droplet/Polymer Films", Proc. SPIE 1080, Liquid Crystal Chemistry, Physics, and Applications, (25 July 1989); doi: 10.1117/12.976395; https://doi.org/10.1117/12.976395


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