Effective Interactions between a Pair of Nanoparticles.

0459541 - ÚCHP 2017 RIV GB eng J - Journal Article
Malijevský, Alexandr
Effective Interactions between a Pair of Nanoparticles.
Molecular Physics. Roč. 113, 9-10 (2015), s. 1170-1178. ISSN 0026-8976. E-ISSN 1362-3028
R&D Projects: GA ČR(CZ) GA13-02938S
Institutional support: RVO:67985858
Keywords : nanoparticles * colloids * density functional theory
Subject RIV: CF - Physical ; Theoretical Chemistry
Impact factor: 1.837, year: 2015

We investigate the effective interactions between two nanoparticles (or colloids) immersed in a solvent exhibiting two-phase separation. Using a non-local density functional theory, we determine the dependence of the effective potential on the separation of the nanoparticles when the solvent is near bulk two-phase coexistence. If identical nanoparticles preferentially adsorbing phase alpha are inserted into phase beta, thick wetting layers of the preferable phase alpha develop at their surfaces. At some particular separation h(b) of the nanoparticles, the wetting layers connect to form a single bridge, and the induced effective potential becomes strongly attractive for all distances h < h(b). The bridging is a first order capillary condensation like transition for all radii of the nanoparticles greater than the critical radius R-c, the value of which was estimated to be approximately R-c approximate to 20 sigma for a temperature T/T-c approximate to 0.9, where sigma is the size of the solvent (square-well) particles. For radii R < R-c the process of bridging is continuous. If the same particles are inserted into the preferable phase alpha, the only effective interaction between them is induced by the short-ranged depletion potential. If the nanoparticles have opposite adsorption preferences, only a single wetting layer forms around one of the nanoparticles and the effective interaction is strongly repulsive in both phases. The repulsion, induced by a disruption of the wetting film by the presence of the second particle, is larger and slightly longer-ranged in a low density state.
Permanent Link: http://hdl.handle.net/11104/0259721