Picture of athlete cycling

Open Access research with a real impact on health...

The Strathprints institutional repository is a digital archive of University of Strathclyde's Open Access research outputs. Strathprints provides access to thousands of Open Access research papers by Strathclyde researchers, including by researchers from the Physical Activity for Health Group based within the School of Psychological Sciences & Health. Research here seeks to better understand how and why physical activity improves health, gain a better understanding of the amount, intensity, and type of physical activity needed for health benefits, and evaluate the effect of interventions to promote physical activity.

Explore open research content by Physical Activity for Health...

The intrinsic photorefractive effect in the smectic C* phase of a chiral azobenzene

Saipa, Alexander and Osipov, Mikhail and Lanham, Kenneth W. and Chang, Catherine H. and Walba, David M. and Giesselmann, Frank (2006) The intrinsic photorefractive effect in the smectic C* phase of a chiral azobenzene. Journal of Materials Chemistry, 16. pp. 4170-4177.

Full text not available in this repository. Request a copy from the Strathclyde author

Abstract

The ferroelectric properties in the liquid-crystalline smectic C* phase of the chiral mesogenic azobenzene (S)-4-(4-decyloxy-phenylazo)benzoic acid 4-(1-methylhexyloxy)-3-nitro-phenyl ester (‘W470’) were studied and found to be strongly dependent on the intensity of incident light. The light-induced trans to cis isomerization of the azobenzene chromophore which is an intrinsic constituent of this SmC* mesogen leads to a pronounced photoferroelectric effect since the ferroelectric SmC* ordering is considerably disturbed by the presence of bent-shaped cis-isomer molecules: At increasing light intensity a strong decrease of both SmC* order parameters, spontaneous electric polarization Ps and director tilt angle θ, is observed. It is further seen that even the nature of the ferroelectric transition is affected by the photoisomerization which leads to a crossover from the nearly tricritrical transition observed in the absence of light to a typical second-order transition. This result is interpreted theoretically taking into account a coupling between the director tilt and the biaxial order parameter which is strongly affected by the light-induced generation of the bent-shaped cis-isomers. The dynamics of the intrinsic photoferroelectric effect in W470 was studied by time-resolved measurements of spontaneous polarisation and director tilt.