Smectic-A and smectic-C phases and phase transitions in (8)over-barS5 liquid-crystal-aerosil gels


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Freelon B., Ramazanoglu M. K. , CHUNG P. J. , PAGE R. N. , LO Y., VALDIVIA P., ...Daha Fazla

PHYSICAL REVIEW E, cilt.84, 2011 (SCI İndekslerine Giren Dergi) identifier identifier

Özet

High-resolution x-ray scattering studies of the nonpolar thermotropic liquid crystal 4-n-pentylphenylthiol-4'-n-octyloxybenzoate ((8) over bar S5) in aerosil gel nanonetworks reveal that the aerosil-induced disorder significantly alters both the nematic to smectic-A and smectic-A to smectic-C phase transitions. The limiting (8) over bar S5 smectic-A correlation length follows a power-law dependence on the aerosil density in quantitative agreement with the limiting lengths measured previously in other smectic-A liquid crystal gels. The smectic-A to smectic-C liquid crystalline phase transition is altered fundamentally by the presence of the aerosil gel. The onset of the smectic-C phase remains relatively sharp but there is an extended coexistence region where smectic-A and smectic-C domains can exist.