Solubilization and rheology of the system ascorbic acid-water-polysorbate 80: temperature effects

Abstract

Abstract Changes induced by temperature in the relative position and extent of the isotropic and liquid crystal phases present in the ascorbic acid-water-polysorbate 80 system have been recorded. Increases in temperature reduce the size of the liquid crystal phase. This phase is pseudoplastic, but a small central region also shows thixotropic hysteresis loops. On recycling, most systems show Newtonian behaviour. In the isotropic regions, an increase in temperature results in a fall in log of viscosity proportionate to 1/Tabs, but in the liquid crystal region an increase in temperature may cause a similar fall or, because of a change in the relative position of the system within the liquid crystal region, an increase.