Managing the phase separation in double emulsion by tuning amphiphilicity via a supramolecular route

Double emulsion has attracted intense scientific investigation on account of its use in a wide range of applications. However, the process of its solidification is usually accompanied by the problem of uncontrollable phase separation. In this work, a supramolecular route is proposed to manage the phase separation in double emulsion. Different degrees of phase separations, from complete wetting to partial wetting and complete dewetting, have been achieved in an emulsion system consisting of P4VP-oleic acid. Partial wetting offers a strategy for generating polymer particles with controllable anisotropic structures. It is demonstrated that the amphiphilicity of polymer matrix, relying on the change of polymer-acid ratio or the chain length of aliphatic acid, is of vital importance for determining the degree of phase separation. A spreading and wetting theory is established to predict and explain the formation of partial wetting.