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Proceedings Paper

Video microscopy of NCAP films: the observation of LC droplets in real time
Author(s): Robert H. Reamey; Wayne Montoya; Abraham Wong
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Paper Abstract

We have used video-microscopy to observe the behavior of liquid crystal (LC) droplets within nematic droplet-polymer films (NCAP) as the droplets respond to an applied electric field. The textures observed at intermediate fields yielded information about the process of liquid crystal orientation dynamics within droplets. The nematic droplet-polymer films had low LC content (less than 1 percent) to allow the observation of individual droplets in a 2 - 6 micrometers size range. The aqueous emulsification technique was used to prepare the films as it allows the straightforward preparation of low LC content films with a controlled droplet size range. Standard electro-optical (E-O) tests were also performed on the films, allowing us to correlate single droplet behavior with that of the film as a whole. Hysteresis measured in E-O tests was visually confirmed by droplet orientation dynamics; a film which had high hysteresis in E-O tests exhibited distinctly different LC orientations within the droplet when ramped up in voltage than when ramped down in voltage. Ramping the applied voltage to well above saturation resulted in some droplets becoming `stuck'' in a new droplet structure which can be made to revert back to bipolar with high voltage pulses or with heat.

Paper Details

Date Published: 15 June 1992
PDF: 6 pages
Proc. SPIE 1665, Liquid Crystal Materials, Devices, and Applications, (15 June 1992); doi: 10.1117/12.60371
Show Author Affiliations
Robert H. Reamey, Raychem Corp. (United States)
Wayne Montoya, Raychem Corp. (United States)
Abraham Wong, Raychem Corp. (United States)

Published in SPIE Proceedings Vol. 1665:
Liquid Crystal Materials, Devices, and Applications
Paul S. Drzaic; Uzi Efron, Editor(s)

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