A Transient Network Structure in Sucrose Stearate/Water Systems

Abstract

slip through at the transient entanglement. 12) Because the mechanism of the mechanical relaxation of temporally entangled thread-like molecular assemblies is not well understood, further studies on a wide range of such materials are required. From the perspective of industrial application, the thread-like molecular assemblies are a promising candidate for novel drug delivery system on account of their relatively large hydrophobic space. 10) If we can engineer the system to have a stimuli response property, it could become a smart delivery The rheological properties of an industrial-grade sucrose stearate aqueous solution were studied. This solution at 1 to 8 wt % appeared translucent or turbid from 20 to 48 °C; however, it became transparent above 48 °C and its viscosity increased. Furthermore, the apparent viscosity of the sample solution increased with temperature, and showed peak value at 48 °C for all such samples. On the other hand, small angle laser-light scattering studies revealed that the molecular-assembly size of the surfactant abruptly decreased at the same temperature. The dynamic modulus of the sample at approximately 48 °C was successfully analyzed with a bimodal Maxwell model, which showed that sucrose stearate formed several types of molecular assemblies and the shape was dependent on temperature. In particular, the rheological properties at approximately 48 °C strongly suggest that the surfactant formed thread-like molecular assemblies.