Pickering high internal phase emulsions (HIPEs), in which the volume fraction of the internal phase exceeds 74%,[1] are frequently used in food, cosmetics, and drug formulations medicine industries in view of their outstanding stability.[2] When stimuli-sensitive nanoparticles are used as emulsion stabilizers, it becomes possible to control the emulsion stability with external stimuli.[3] We report here dual-sensitive emulsion stabilizers consisting of thermo-sensitive Poly(N-isopropylacrylamide) (PNIPAm) nanogels decorated with photo-sensitive azobenzene moieties and their use in Pickering HIPEs. The approach is illustrated in Scheme 1. The nanogels were prepared by a one-step synthetic route in aqueous media. Nanogels aqueous suspensions (concentration as low as 0.2wt%) were mixed with an oil phase yielding Pickering oil-in-water HIPEs with oil volume phase fraction as high as 96vol%. The thermo/photo sensitivity, droplet size and viscosity of Pickering HIPEs were studied by UV, microscopy and viscometry. Synthetic and natural oils were utilized with equal succes [1] N.R. Cameron, D.C. Sherrington, Advances in Polymer Science, 1996, 126, 163 [2] (a) N. R. Cameron, Polymer, 2005, 46, 1439; (b) M. P. Aronson and M. F. Petko, J. Colloid Interface Sci., 1993, 159, 134; (c) G. J. Lye and D. C. Stuckey, Colloids Surf., A, 1998, 131, 119; [3] B. Brugger, B. A. Rosen, W. Richtering, Langmuir, 2008, 24, 12202

One-step preparation of thermo/photosensitive nanogels and their use as stabilizers of Pickering high internal phase emulsions

249th National Meeting (2015)

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