Spontaneous ethanol–water emulsification as a precursor for porous particle formation: Understanding the role of dissolved carbohydrates
P.L. Xiaoa,b, S. Mansouria, V. Suriya Henaa, Y.K. Bonga, K. Hapgoodc, M.W. Wooa,*
• Dissolved carbohydrates can function as surfactants in an ethanol–water environment. • Transient spontaneous ethanol–water emulsification occurs without an oil phase. • Delicate balance exists between spontaneous emulsification and solute precipitation. • A precursor step exists for porous-particle formation in ethanol–water mixtures.
Quiescent mixing of aqueous lactose solution with ethanol by gentle pouring allowed controlled observation of a transient, spontaneous emulsification process between ethanol and water. This phenomenon contrasts with the conventional stable phase-separation process for ethanol–water systems with other solutes. The presence of lactose in the dissolved state was deduced to be the key factor causing spontaneous emulsification. This explains the transitional behavior of the phenomenon. Further experiments with aqueous maltodextrin solution, using the same experimental technique, confirmed this phenomenon. The mechanisms determined in this work will form the basis of porous-particle synthesis via the antisolvent vapor-precipitation technique.