LAUSR

For the purpose of encapsulating curcumin, cubic liquid crystals were constructed using a Brij 97-NaDC (surfactant)/IPM-PEG 400 (oil)/H2O system, at a constant Brij 97/NaDC ratio of 4:1 and varied IPM/PEG 400 ratios of 9:1, 8:2, 7:3, 6:4, 5:5, 4:6, and 3:7. The cubic liquid crystal samples, possessing a fixed surfactant/oil/water composition and different IPM/PEG 400 ratios, underwent a structure transition from Im3m to the coexistence of Im3m and Ia3d as determined by small-angle X-ray scattering (SAXS) measurements. SAXS and rheological investigations on the 5:5 IPM/PEG 400 ratio cubic samples suggested that the cubic liquid crystals became more stable after encapsulating curcumin in either IPM or PEG 400, as indicated by the longer characteristic relaxation time. By saturating curcumin in both IPM and PEG 400, at an IPM/PEG 400 ratio less than 5:5, higher elastic modulus, larger q value, and stronger intensity of the first scattering peak for the curcumin-encapsulated liquid crystals were observed as compared to the corresponding curcumin-free samples. Also, clearly different melting points for these systems were found. These results indicate a method of tailoring the stability and the temperature sensitivity of the investigated curcumin-encapsulated cubic liquid crystals.