摘要:

A magnetically-induced Freedericksz transition was used in conjunction with capacitance techniques to determine the splay elastic constant of the 4,4′-dialkoxyphenylbenzoate monomer ‘5OO5rsquo; [C5H11OC6H4COOC6H4OC5H11] and its dimer. As a function of reduced temperature in the nematic phase, it was found thatK11of the dimer is only about 20 per cent larger than that of the monomer. Moreover, the values ofK11/S2versus reduced temperature, whereSis the scalar order parameter, are equal to within experimental noise. These results suggest that for short oligomers Meyer's entropic model for splay elasticity in polymer liquid crystals is not applicable. A lowest order correction to the entropic model is suggested, which partially accounts for excluded volume and dispersive effects.

ISSN:0267-8292    

DOI:10.1080/02678299008047359

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The dielectric polarization has been used to study dipolar association of 4-n-pentyl-4′-cyanobiphenyl in benzene solution. The results have been interpreted with the assumption of a monomer–dimer equilibrium. To explain the relatively high effective dipole moment of the dimers, a new structure has been proposed for them.

ISSN:0267-8292    

DOI:10.1080/02678299008047360

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor