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Optical investigations of free-standing liquid-crystal films, in particular, the films possessing a net electrical dipole moment to acquire the molecular orientational arrangements within the films. We have been empolying the following three probes: ellipsometry, differential optical reflectivity and depolarized reflected light microscopy. In collaboration with other research groups, we have been utilizing polarization analyzed resonant x-ray diffraction to determine the molecular orientational order in various mesophases found in rod-like and bent-core liquid crystal compounds.
P. Fernandes, P. Barois, S. T. Wang, Z. Q. Liu, B. K. McCoy, C. C. Huang, R. Pindak, W. Caliebe, and H. T. Nguyen, Polarization studies of resonant “Forbidden” reflections in liquid crystals, Phys. Rev. Lett. 99, 227801 (2007).
P. D. Brimicombe, N.W. Roberts, S. Jaradat, C. Southern, S.T. Wang, C.C. Huang, E. DiMasi, R. Pindak, and H.F. Gleeson, “Deduction of the temperature-dependent structure of the four-layer intermediate smectic phase using resonant x-ray scattering”, Eur. Phys. J. E 23, 281 (2007)
Z. Q. Liu, B. K. McCoy, S. T. Wang, R. Pindak, W. Caliebe, P. Barois, P. Fernandes, H. T. Nguyen, C. S. Hsu, Shung Wang and C. C. Huang, Unique Pitch Evolution in the Smectic-C*_alpha Phase, Phys. Rev. Lett. 99, 077802 (2007).
B. K. McCoy, Z. Q. Liu, S. T. Wang, R. Pindak, K. Takekoshi, K. Ema, A. Seed, and C. C. Huang, , “SmC* phase with two coexistent pitch values and a first order SmC_alpha*-SmC* transition”, Phys. Rev. E 75, 051706 (2007)
Z. Q. Liu, S. T. Wang, B. K. McCoy, A. Cady, R. Pindak, W. Caliebe, K. Takekoshi, K. Ema, H. T. Nguyen, and C. C. Huang, “Smectic-C*-smectic-C* phase transition and critical point in binary mixtures”, Phys. Rev. E 74, 030702 (R) (2006)
S.T. Wang, X.F. Han, Z.Q. Liu, B. McCoy, and C.C. Huang, “Optical studies on the surface induced tilted layers in freestanding films of two no-layer-shrinkage liquid crystal compounds”, Phys. Rev. E 74, 031707 (2006)
V. P. Panov, B. K. McCoy, Z. Q. Liu, J. K. Vij, J. W. Goodby, and C. C. Huang, “Investigations of nano-scale helical pitch in SmC* and SmC* phases of a chiral smectic liquid crystal using differential optical reflectivity measurements”, Phys. Rev. E 74, 011701 (2006)
M. P. Veum, M. K. Blees, N. Voshell, H. T. Nguyen, and C. C. Huang, “The role of molecular weight and phase sequence in the temperature variation of film tension above the bulk isotropic transition in freestanding liquid crystal films”, Phys. Rev. E 74, 011703 (2006)
D. M. Walba, E. Korblova, C. C. Huang, R. Shao, M. Nakata, and N. A. Clark, “Reflection symmetry breaking in achiral rod-shaped smectic liquid crystals?”, J. Am. Chem. Soc. 128, 5318 (2006)
B. K. McCoy, Z. Q. Liu, S. T. Wang, V. P. Panov, J. K. Vij, J. W. Goodby, and C. C. Huang, “Surface-induced multiple reentrant transitions,”, Phys. Rev. E 73, 041704 (2006)