Solid-solid phase transition of (1-C14H29NH3)2ZnCl4 in nanopores of silica gel for thermal energy storage

Latent heat storage performance of a layered perovskite-type compound, 1-C14H29NH3）2ZnCl4（C14Zn）,embedded in a series of silica gel（SG） with pore sizes of d = 15–200 nm is investigated using differential scanning calorimetry（DSC）, and powder X-ray diffractions（XRD）. C14Zn in the nanopores of silica gel shows size-dependent phase transition temperature, enthalpy change and supercooling. They have a stable transition temperature and heat capacity at each size in a short-term thermal cycling. Similar Xray diffraction patterns are observed for the nano-sized and the bulk C（14）Zn. The encapsulation of a phase change material in nanopores is a new way of tuning its thermal energy storage properties for a wider range of temperature regulation.

Phase behavior of undecane–tetradecane mixtures confned in SBA-15

Phase behavior of undecane-tetradecane （n-C11H24-C14H3o, C11-C14） mixtures in bulk and confined in SBA-15 have been studied using differential scanning calorimetry. The bulk C11-C14 system shows multiple phase regions due to rotator phase. Confined in the pores of SBA-15 （pore diameters 3.8- 7.8 rim）, the mixtures only show a melting boundary of a straight line and a curve, respectively. In SBA- 15 （ 17.2 nm）, phase behavior of the mixtures has some similarity to that of the bulk. Under confinement, the phase diagrams of the mixtures vary with the pore size, temperature, and compositions.