Molecular mechanisms of interface interactions in Pickering emulsions co-stabilized by β-cyclodextrins and Tween 60.

The interface interactions in Pickering emulsions are determined by molecular interactions at the microscopic scale in essence. The interfacial properties of β-CD/Tween 60 co-stabilized emulsions were investigated experimentally and numerically. The results show that Tween 60 can increased the hydrophilicity of β-CD. The interface thickness of the β-CD/Tween 60 co-stabilized emulsion is about twice as thick as that of β-CD stabilized system. The formation of hydrogen bonds and electrostatic interaction between β-CD and Tween 60 might be the reason for the variation of surface characteristics of β-CD. Besides, it was demonstrated that the alkyl chain end of Tween 60 can enter into the cavity of β-CD, indicating the formation of the assemblies, approximately 20-30 hydrogen bonds were formed. The magnitude of van der Waals interactions exceeds that of electrostatic interaction, indicating that both hydrogen bonds and van der Waals interactions are the main driving force.