초록 |
Tween 20 (T20) is mostly used as a non-ionic emulsifier in cosmetic, scientific, and pharmacological applications. Cinnamic acid (CA) which is potential for anti-oxidation and anti-ultraviolet was conjugated to T20 by esterification. The molar ratio of CA residue/T20 residue was calculated to be 1.84/1.02 on 1H NMR spectrum. The air/water interface tension of T20 and CA conjugate (TCC) was a litter lower than T20, might due to the hydrophobicity of ester group of TCC. Moreover, the dimerization degree of TCC was higher than free CA possibly because the distance of CAs in TCC was much closer. The ultraviolet spectra showed that the extinction coefficient of TCC was about 3470 M-1cm-1 which is potential for anti-ultraviolet agent. And TCC was used as an emulsifier to prepare oil-in-water emulsion. As shown on the microscopy, the size of the emulsion was about 4.5 μm and kept stable for 48hr. After irradiation with UV light, the size markedly increased due to the photo collapse of TCC. |