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Updated: Jul 25, 2025
Electroactive Polymer Nanoparticles Exhibiting Photothermal Properties
Published on: January 8, 2016
Diffusiophoresis of latex driven by anionic nanoparticles and their counterions
Clare R Rees-Zimmerman1, Derek H H Chan2, Steven P Armes2
1Institute of Energy and Environmental Flows, Department of Chemical Engineering & Biotechnology, University of Cambridge, Madingley Rise, Cambridge CB3 0EZ, UK.
Hypothesis:
Diffusiophoresis of colloidal latex particles has been reported for molecular anions and cations of comparable size. In the present study, this phenomenon is observed for two types of charged colloids acting as multivalent electrolyte: (i) anionic charge-stabilised silica nanoparticles or (ii) minimally-charged sterically-stabilised diblock copolymer nanoparticles.
Experiments:
Using a Hele-Shaw cell, a thin layer of relatively large latex particles is established within a sharp concentration gradient of nanoparticles by sequential filling with water, latex particles and nanoparticles. Asymmetric diffusion is observed, which provides strong evidence for diffusiophoresis. Quantification involves turbidity measurements from backlit images.
Findings:
The latex particles diffuse across a concentration gradient of charged nanoparticles and the latex concentration front scales approximately with time1/2. Moreover, the latex particle flux is inversely proportional to the concentration of background salt, confirming electrostatically-driven motion. These observations are consistent with theory recently developed to account for diffusiophoretic motion driven by multivalent ions.
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