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The influence of the boundary conditions on the character of the phase transition nematic‐smectic C
Author(s) -
Simova P.,
Petrov M.
Publication year - 1987
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.2170220522
Subject(s) - liquid crystal , homeotropic alignment , tilt (camera) , phase (matter) , phase transition , condensed matter physics , materials science , orientation (vector space) , crystallography , phase boundary , molecule , optics , chemistry , geometry , physics , organic chemistry , mathematics
The possibility is investigated for inducing the intermediate smectic A structure in substances with nematic and smectic C phases by the boundary forces. Different geometries are used: homeotropic, homogeneous and tilted under a different angle toward the supporting substrates of the liquid crystal cell. At homeotropic and at tilted orientation where the molecules tilt toward the supporting substrates is different from the molecule tilt in the smectic layer, an intermediate smectic A structure is observed at the transition nematicsmectic C in a narrow temperature interval. In this case the phase transition nematicsmectic C extends and transforms into phase transition of second order. At homogeneous orientation and at tilted orientation of an angle equal to the molecule tilt in the smectic layer, the transition nematic‐smetic C carried out in two stages, as partially it begins on the surface still in the nematic phase and terminates at the temperature of the phase transition N‐Sc. The influence of the boundary forces depends essentially on the energy of the phase transition N‐S C of the substances.