Particle aggregation mechanisms in ionic liquids

Article Article scientifique Article Particle aggregation mechanisms in ionic liquids eng 2014 author Szilagyi Istvan 702956 author Szabo Tamas 798070 author Desert Anthony 798009 author Trefalt Gregor 786132 author Oncsik Tamas 781718 author Borkovec Michal 134121 9515-9524 10.1039/C4CP00804A 1463-9076 http://xlink.rsc.org/?DOI=C4CP00804A Aggregation of sub-micron and nano-sized polystyrene latex particles was studied in room temperature ionic liquids (ILs) and in their water mixtures by time-resolved light scattering. The aggregation rates were found to vary with the IL-to-water molar ratio in a systematic way. At the water side, the aggregation rate is initially small, but increases rapidly with increasing IL content, and reaches a plateau value. This behaviour resembles simple salts, and can be rationalized by the competition of double-layer and van der Waals forces as surmised by the classical theory of Derjaguin, Landau, Verwey, and Overbeek (DLVO). At the IL side, aggregation slows down again. Two generic mechanisms could be identified to be responsible for the stabilization in ILs, namely viscous stabilization and solvation stabilization. Viscous stabilization is important in highly viscous ILs, as it originates from the slowdown of the diffusion controlled aggregation due to the hindrance of the diffusion in a viscous liquid. The solvation stabilization mechanism is system specific, but can lead to a dramatic slowdown of the aggregation rate in ILs. This mechanism is related to repulsive solvation forces that are operational in ILs due to the layering of the ILs close to the surfaces. These two stabilization mechanisms are suspected to be generic, as they both occur in different ILs, and for particles differing in surface functionalities and size. Dewey 540 40 Département de chimie minérale, analytique et appliquée 145 false Physical Chemistry Chemical Physics 16 20 f0bd72b2-8a92-4300-bee4-50c852dd19c4 Article (Published version) Public Particle_MB_14.pdf 3325969 application/pdf openAccess Faculté des sciences / Section de chimie et biochimie / Département de chimie minérale, analytique et appliquée

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Particle aggregation mechanisms in ionic liquids	Physical Chemistry Chemical Physics			2014	226	125

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Szabo, Tamas