Résumé
Gold nanoparticles (NPs) coated with stimuli-responsive polymer transfer from water to oil and from oil to water across the planar interfaces when environmental parameters are slightly changed. The oil to water transfer occurs when the temperature is reduced below 5 °C, while they transfer from salty water to oil when the environmental temperature returns to room temperature. The water-to-oil particle transfer after warming is dictated by the ionic strength of the aqueous phase, which is directly associated with the ionic strength response of the polymer brushes anchored on the NPs. In contrast, the temperature onset for the oil-to-water NP transfer after cooling is weakly correlated with the transition temperature of the polymer brushes in either of the bulk phases. The transfer mechanism disparity for the two directions during NP crossing of oil-water interfaces result from an intricate interplay of interfacial interactions and transitions. In this talk, experimental investigations and some modeling will be presented in order to elucidate the NP transfer across fluid interfaces. References Bidirectional Nanoparticle Crossing of Oil-Water Interfaces Induced by Different Stimuli: Insight into Phase Transfer. Stocco Antonio, Chanana Munish, Su Ge, Cernoch Peter, Binks Bernard, Wang Dayang: Angewandte Chemie / Angew Chem Int Ed, vol. 51 p.9647 (2012) Acknowledgements Special thanks go to Helmuth Möhwald, Munish Chanana (MPIKG), and all colleagues involved in this project.