Impact of pNIPAM microgel size on its ability to stabilize Pickering emulsions.
We study the influence of the particle size on the ability of poly(N-isoprolylacrylamide) microgels to stabilize direct oil-in-water Pickering emulsions. The microgel size is varied from 250 to 760 nm, the cross-linking density being kept constant. The emulsion properties strongly depend on the stabilizer size: increasing the particle size induces an evolution from dispersed drops and fluid emulsions toward strongly adhesive drops and flocculated emulsions. In order to get insight into this dependency, we study how particles adsorb at the interface and we determine the extent of their deformation. We propose a correlation between microgel ability to deform and emulsion macroscopic behavior. Indeed, as the microgels size increases, their internal structure becomes more heterogeneous and so does the polymeric interfacial layer they form. The loss of a uniform dense layer favors bridging between neighboring drops, leading to flocculated and therefore less handleable emulsions.
Centre de Recherche Paul Pascal, Université de Bordeaux , 115 Avenue Dr Albert Schweitzer, 33600 Pessac, France.
Mathieu
M
Destribats
Mayalen
M
Eyharts
Véronique
V
Lapeyre
Elisabeth
E
Sellier
Imre
I
Varga
Valérie
V
Ravaine
Véronique
V
Schmitt
D000180:Acrylic Resins / Q000737:chemistry*; D004655:Emulsions / Q000737:chemistry; D005782:Gels / Q000737:chemistry*; D009821:Oils / Q000737:chemistry; D010316:Particle Size; D013499:Surface Properties; D014867:Water / Q000737:chemistry
D000180:Acrylic Resins; D004655:Emulsions; D005782:Gels; D009821:Oils; D014867:Water; C052970:poly-N-isopropylacrylamide