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Interface effects in nematic liquid‐crystalline structures of polymer solutions
Author(s) -
Kuznetsov Dmitri V.
Publication year - 1996
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.19961060121
Subject(s) - liquid crystal , isotropy , spinodal , materials science , distribution function , polymer , phase (matter) , condensed matter physics , orientation (vector space) , perpendicular , virial theorem , thermodynamics , physics , optics , geometry , mathematics , quantum mechanics , galaxy , composite material
A solution of long semirigid linear macromolecules was considered. The liquid‐crystalline nematic ordering in the solution was analyzed theoretically using an Onsager‐type approach. The orientation entropy was calculated in the frameworks of Lifshits' approach, successfully developed for this system originally by Khokhlov and Semenov. For homogeneous liquid‐crystalline phase using the third virial approximation for intersegmental steric interaction the orientation distribution function, the free energy density, the isotropic‐nematic coexistence and the spinodal conditions were computed numerically for two types of polymer flexibility mechanism: persistent chains and chains of freely joint segments. For the asymptotically exact second virial approximation the applicability region was analyzed. We considered the general equations, which describe the concentration and orientational segment distribution for a semirigid persistent polymer chain at a surface (or interface) of any shape and orientation. These equations were numerically solved for the case when the nematic director axis was perpendicular to a planar interface boundary between the real coexisting nematic and isotropic phases. The coordinate‐dependencies of the polymer concentration and of the order‐parameter take the smooth two‐steps form in the interface region.