283158 Towards Stimulus-Responsive Control of Foam and Emulsion Stability Using Nanoparticles

Thursday, November 1, 2012: 1:35 PM
412 (Convention Center )
Filippo Gambinossi, Lafayette College, Easton, PA and James K. Ferri, Department of Chemical and Biomolecular Engineering, Lafayette College, Easton, PA

The physics and engineering of switchable stability in foams and emulsion systems depends of active control of the fluid/fluid interface. We utilize nanoparticles with designed surface chemistry to control the contact angle of the nanoparticle at the fluid/fluid interface, the free energy of attachment, ultimately the interfacial elasticity. Interrogation of the aggregation kinetics and rheology of the fluid/fluid interface enables elucidation into fundamental mechanisms of foam and emulsion stabilization.

Here, we discuss a new class of thermosensitive polymeric materials based on random copolymers  which display a lower critical solution temperature (LCST) in water that is dependant on co-polymer ratio and ionic strength. Gold nanoparticles grafted with thermosensitive polymer brushes of these copolymers have switchable aggregation kinetics (k11) and interfacial elasticity (E*).  We show the dependence of k11 and the complex interfacial modulus (E*) on environmental conditions such as salt concentration and temperature; it is demonstrated that switchable stabilization is controlled by bulk aggregation rate, rather than interfacial rheology.

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See more of this Session: Emulsions and Foams II
See more of this Group/Topical: Engineering Sciences and Fundamentals