Ultrasonic study of the shear mechanical impedance of butyloxybenzylidene octylaniline near the crystalline-B-smectic-A phase transitionReport as inadecuate




Ultrasonic study of the shear mechanical impedance of butyloxybenzylidene octylaniline near the crystalline-B-smectic-A phase transition - Download this document for free, or read online. Document in PDF available to download.



Abstract : We report a detailed study of the shear mechanical impedance near the crystalline-B-smectic-A transition in butyloxybenzylidene octylaniline 40.8. The measurements were performed at various frequencies from 5 to 85 MHz for shear waves propagating along the normal to the layers. In both phases the material response presents strong relaxation effects. The structure change at the transition is indicated by an increase in the real part of the shear impedance. The results at 85 MHz are those expected for a first-order transition broadened by impurity concentration, whereas the results at 5 MHz reveal a pretransitional effect in a temperature interval of 2-3 °C below the transition.

Keywords : liquid crystal phase transformations mechanical properties of liquids organic compounds smectic liquid crystals ultrasonic relaxation ultrasonic study shear mechanical impedance butyloxybenzylidene octylaniline crystalline B smectic A phase transition 5 to 85 MHz shear waves relaxation effects structure change first order transition impurity concentration pretransitional effect





Author: Y. Thiriet P. Martinoty

Source: https://hal.archives-ouvertes.fr/



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