The Elucidation of the Critical Role of HLB value in Microemulsions Formulation

Microemulsions are extensively utilized in food, pharmaceuticals, and cosmetics due to their superior solubilizing capacity and protective capabilities. However, a longstanding critical issue with microemulsions is the quantitative relationship between the HLB value and the physicochemical properties. Herein, to quantify the effect of the HLB value on microemulsions, Juniperus chinensis Roxb. essential oil (CEO) microemulsions were fabricated. It is certified that HLB values between 8.5 and 11.5 correspond to the smallest biphasic regions, while values between 9.5 and 13.5 correspond to the largest monophasic regions. Besides, the phase evolution from lamellar structures to microemulsions was monitored by the Small-Angle X-ray Scattering (SAXS) patterns. The physicochemical properties of the resulting emulsions, e.g., polydispersity indices (PDI), zeta potential, thermal stability, viscosity, and conductivity, were also investigated. The quantification of the effect of the HLB value on the formation of microemulsions will provide significant quantitative and theoretical guidance to researchers and industry professionals.