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Article
Direct Observation of Diffuse Cone Behavior in De Vries Smectic-A and -C Phases of Organosiloxane Mesogens
Physical Review Letters
  • HyungGuen Yoon, Kent State University - Kent Campus
  • Dena M. Agra-Kooijman, Kent State University - Kent Campus
  • Khurshid Ayub, COMSATS Institute of Information Technology
  • Robert P. Lemieux, Queen's University - Kingston, Ontario
  • Satyendra Kumar, Kent State University - Kent Campus
Publication Date
2-24-2011
Document Type
Article
DOI
10.1103/PhysRevLett.106.087801
Keywords
  • Resolution X Ray,
  • Liquid Crystals,
  • Layer Thickness,
  • Transition,
  • Tilt
Disciplines
Abstract
Simultaneous and direct x-ray measurements of the smectic layer spacing, molecular tilt, and orientational order in the de Vries smectic A (SmA) and C (SmC) phases of two organosiloxane mesogens reveal that (i) the SmC (tilt) order parameter exponent beta = 0.26 +/- 0.01 for 2nd order SmA-SmC transition-in excellent agreement with the tricritical behavior, (ii) the siloxane and hydrocarbon parts of the molecules are segregated and oriented parallel to the director with very different degree of orientational order, and (iii) thermal evolution of the effective molecular length is different in the two phases.
Comments

Copyright 2011 American Physical Society. Available on publisher's site at http://dx.doi.org/10.1103/PhysRevLett.106.087801.

Citation Information
HyungGuen Yoon, Dena M. Agra-Kooijman, Khurshid Ayub, Robert P. Lemieux, et al.. "Direct Observation of Diffuse Cone Behavior in De Vries Smectic-A and -C Phases of Organosiloxane Mesogens" Physical Review Letters Vol. 106 Iss. 8 (2011)
Available at: http://works.bepress.com/satyendra_kumar/39/