The rheology of polyvinylpyrrolidone-coated silica nanoparticles positioned at an air-aqueous interface
Journal Publication ResearchOnline@JCUAbstract
Particle-stabilized emulsions and foams are widely encountered, as such there remains a concerted effort to better understand the relationship between the particle network structure surrounding droplets and bubbles, and the rheology of the particle-stabilized interface. Poly(vinylpyrrolidone)-coated silica nanoparticles were used to stabilize foams. The shear rheology of planar particle-laden interfaces were measured using an interfacial shear rheometer and the rheological properties measured as a function of the sub-phase electrolyte concentration and surface pressure. All particle-laden interfaces exhibited a liquid-like to solid-like transition with increasing surface pressure. The surface pressure-dependent interfacial rheology was then correlated to the formed micron-scale structures of the particle-laden interfaces which were imaged using a Brewster angle microscope. With the baseline knowledge established, foams were prepared using the same composite particles and the particle network structure imaged using cryo-SEM. An attempt has been made to correlate the two structures observed at a planar interface and that surrounding a bubble to elucidate the likely rheology of the bubble stabilizing particle network. Independent of the sub-phase electrolyte concentration, the resulting rheology of the bubble stabilizing particle network was strongly elastic and appeared to be in a compression state at the region of the L-S phase transition.
Journal
Journal of Colloid and Interface Science
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Volume
527
ISBN/ISSN
1095-7103
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Pages Count
10
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Publisher
Elsevier
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EISSN
N/A
DOI
10.1016/j.jcis.2018.05.035