Study On The Influencing Factors And Emulsification Mechanism Of Nano-emulsion Prepared By D-phase Emulsification

Nano-emulsions have a wide application prospect in the field of cosmetics due to its unique nano particle size,excellent thermodynamic stability,transparent appearance and high specific surface area.In recent years,low-energy emulsification methods for preparing nano-emulsions has attracted widespread attention from scholars because it does not depend on special highenergy equipment,has low energy consumption,and is easy to operate.D phase emulsification method,which has unique advantages in academic research and practical application,was selected in this paper.The influencing factors of nano-emulsions preparation were discussed,and the emulsification mechanism of D phase emulsification method was analyzed.D phase emulsification method was applied to prepare nano-emulsions in the Span 80-Tween 80/glycerin/ mineral oil/water system firstly in this paper.The phase behavior of this system during the entire emulsification process and the stability of the prepared emulsions were investigated by means of a pseudo-ternary phase experimental design.Experiments showed that there was no strict correspondence between the different regions of the O/D phase diagram and the regions where the O/W nano-emulsions were formed.At higher surfactants/glycerin content(7.5:2.5),nano-emulsions can be prepared while the oil content below 80% and water content above 50 wt%.At lower surfactants/glycerin content(2.1:7.9),stable nano-emulsion can be prepared while the oil content below 25% and water content above 50 wt% during the 30 days storage period.These experimental results demonstrated the important effect of emulsifiers content on nano-emulsions formation and stability.Then,the effect of oil types on the formation and stability of nano-emulsions by D phase emulsification method was investigated comprehensively in this paper.Three kind of oils(straight-chain alkanes,branched alkanes,and esters oils)were used and the formation of the nano-emulsions was studied.The stability of prepared nano-emulsions was characterized by the variation curve of the droplet mean diameter within 28 days.It has been found that for alkane oils,the molecular weight was important to the formation and stability of nano-emulsions.For ester oils containing heteroatoms in the structure,nano-emulsions with bigger particles tended to be formed due to the better affinity of oils to glycerin.In addition,it was found that the formation and stability of nano-emulsions should be discussed separately.Temperature had different effects at different preparation processes.Finally,the effects of different emulsifier systems on the preparation of nano-emulsions by D phase emulsification method were discussed.Two new types of emulsifiers: PEG fatty acid glyceride emulsifiers and polyglycerol fatty acid ester emulsifiers were selected to blend with different types of oils.Experiments showed that the type of hydrophobic group had a greater effect on the formation of nano-emulsions followed by the appropriate HLB value for PEG fatty acid glyceride emulsifiers.PEG-8 glyceryl isostearate and PEG-20 glyceryl triisostearate were excellent in participating in the D phase emulsification process due to their moderate HLB values and suitable hydrophobic tail,and they could emulsify most oils.In addition,when the polyglycerol fatty acid ester emulsifiers were used as a single emulsifier in the system,oils could not be emulsified to form nano-emulsions..