Study On The Influencing Factors Of The Formation And Stability Of O/W/O Multiple Emulsion

As a special structure,the multi-structure emulsion can not only provide good skin feel,but also encapsulate the active ingredients and irritating ingredients to achieve slow release and reduce irritation effects and it attracts more and more scholars to study it.However,due to the complex preparation process and low stability of the multiple emulsion,the mechanism of its formation and stabilization is not clear and,it is difficult to commercializetill now.Therefore,it is imperative to explore the influencing factors and mechanism of the formation and stability of multiple emulsions.This study selceted O/W/O multiple emulsion as the research object,which was more challenging,aiming to investigate the composition,preparation process and the primary mechanism of the oil and emulsifier on the formation and stability of O/W/O multiple emulsions.In this paper,the initial formula was drawed up,and the influence of formula composition and preparation process on the formation of multiple emulsion was studied by two-step emulsification method,with the aim to screen the optimal formula composition and preparation process for the preparation of O/W/O multiple emulsion.Through the experimental results,it is found that the best ratio of O/W emulsifier F217:S21 was 3:5,the viscosity of the inner phase oil was 350 cs,the outer phase oil was 50 cs,and 5% 1,3-butanediol which wass the best formulation for preparing O/W/O multiple emulsion;The optimal emulsification process was chosen ultrasonic emulsificaion as the first-step emulsification process and in the second step,650r/min was selected as stirring speed and 60℃ was used to prepare O/W/O multiple emulsion.Secondly,under the conditions of determining the optimal formula composition and preparation process,the interface characteristics of the two opposite interface films of the O/W/O multiple emulsion,namely the internal O/W interface and the external W/O interface were investigated.The effects of different oils and emulsifiers and other additives on the stability of the oil-water interface film were studied.Furthermore,the effects of interface characteristics on the formation and stability of O/W/O multiple emulsions were discussed.The results found that when the emulsifier and the oil had better compatibility,a relatively stable oil-water interface can be formed,which was beneficial to the formation and stability of the O/W/O multiple emulsion.For the O/W interface,when the emulsifier F217/S21 was combined and the inner phase oil was 350 cs,the O/W interface film formed was relatively stable,which was conducive to the formation and stability of OW/O multiple emulsionmultiple emulsion.For different W/O emulsifiers,the W/O interfacial film formed by 9011 and 50 cs silicone oil for external oil was relatively stable,so the O/W/O multiple emulsion formed by it had the best stability.The addition of the oil phase stabilizer obviously improved the stability of the emulsion to a certain extent,and the addition of the oil phase stabilizer gas silicon was more conducive to the stability of the system.Finally,considering the diversity of oils and emulsifiers in cosmetic systems,a preliminary study was made on the rules and formation mechanisms of OWO multiple structures formed by different oils and emulsifiers.The experimental results showed that: in the formation of O/W/O emulsion,the external W/O emulsifier had a greater impact on the system.The emulsifier can introduce different chemical structures,different hydrophobic chain lengths,and branches in the hydrophobic end.And the difference in the end group structure made its ability to reduce the interfacial tension different,which lead to different emulsification effects.Because of its unique chemical structure and appropriate HLB value,emulsifier EM90 was more conducive to the formation of stable O/W/O multiple emulsion.multiple emulsion.However,the internal O/W emulsifier had relatively little influence on the formation of O/W/O multiple structure,and can form multiple emulsion in all kinds of oils.For oils,the curvature radius of emulsified particles formed by polar oils 318 and IPM was relatively small and stable compared with that of non-polar oilmultiple emulsion...