摘要:

The field effects in nematic liquid crystal layers are reanalysed using catastrophe theory. The layer with pretilted director orientation and obliquely applied magnetic field, the hybrid aligned nematic cell and twisted nematic structures are considered. The stable solutions are identified and transitions between them are specified. The results are in essential agreement with previous work. Some details concerning the behaviour near the threshold are revealed.

ISSN:0267-8292    

DOI:10.1080/02678298808086621

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

We have studied the influence of thermally excited orientational fluctuations on the N.M.R. lineshape of a nematic monodomain. The influence is characterized by a static order parameterSstatwhose theoretical expression in terms of viscoelastic parameters is derived. This model is applied to the proton N.M.R. spectrum of a thermotropic main chain polymer. The values ofSstatare deduced from the study of the changes of the N.M.R. lineshape as a function of the angle between the static magnetic field and the nematic director. Good agreement is obtained with theoretical values calculated using estimated values of the Leslie viscosity coefficients and the Frank elastic constants. The importance of an accurate knowledge ofSstatfor a number of problems is stressed.

ISSN:0267-8292    

DOI:10.1080/02678298808086622

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor