Smectic A: cholesteric phase transition investigated by small angle X-ray diffraction and viscosity measurements

Abstract

) in the N* domain, and the correlation length (epsilon), as well as changes along the N* – A phase transition, were determined from the X-ray diffraction data. The results show a decrease in A phase domain and an expansion of the N* – domain as the mean molecular length is diminished. Such effect induces a second order A – N* phase transition for a particular mixture of 63.1 mol% of C9 and 36.9 mol% of C6, evidenced by viscosity measurements in good agreement with previous density data.]]>

Interaction of Amphotericin B With Cholesteryl Palmityl Carbonate Ester

“…The changes of d-spacing value and diffraction pattern reflect the transition phase behavior of thermotropic liquid crystals. 11 In the case of pure CPC, the cholesteric phase was obtained at 658C, which is characterized by a very broad bimodal peak with weak X-ray diffraction intensity. At $458C (Fig.…”

Smectic A – Cholesteric Phase Transition: A Viscosity Study

“…From a thermodynamic point of view these are first order phase transitions, as evidenced by density discontinuities at the transitions [4,5]. Furthermore, several authors have studied some rheological properties of these compounds [6][7][8]. In this work, we report that the diversity of viscosity curves characterizing the different shear rates to which the system has been submitted can be reduced, through a simple scaling law, to a single line that reveals a single viscosity behavior of the material at each of its phases.…”