Stability of Nano-Sized Aqueous Dispersion of n-Heptadecane to Thermal Cycling

A stable aqueous dispersion of n-heptadecane was prepared by ultrasonification without the addition of surfactants. Using the dynamic light scattering, the characteristic size (hydrodynamic radius) of the dispersion‘s particles (100 nm) was determined. On the basis of temperature dependence measurements of scattered light intensity, the temperatures of melting, crystallization and transition to rotator phase of n-heptadecane particles in the studied dispersion were determined. The results obtained are in good agreement with literature data. It has also been experimentally shown that this aqueous dispersion can withstand up to 400 thermal cycles of heating and cooling from 3 °C to 30 °C, retaining ist colloidal stability. The results obtained allow to consider this dispersion as a promising basis for the development of Phase Change Materials.