Utilize este identificador para referenciar este registo: http://hdl.handle.net/10400.21/668
Título: Equilibrium self-assembly of colloids with distinct interaction sites: Thermodynamics, percolation, and cluster distribution functions
Autor: Tavares, J. M.
Teixeira, Paulo Ivo Cortez
Gama, M. M. Telo da
Sciortino, F.
Palavras-chave: Bonds (chemical)
Chemical equilibrium
Colloids
Liquid structure
Percolation
Perturbation theory
Polymers
Self-assembly
Specific heat
Data: 21-Jun-2010
Editora: Amer Inst Physics
Citação: Tavares J M, Teixeira P I C, Gama M M T, Sciortino F. Equilibrium self-assembly of colloids with distinct interaction sites: Thermodynamics, percolation, and cluster distribution functions.Journal of Chemical Physics. 2010; 132 (23): Art. No. 234502.
Relatório da Série N.º: 23;234502
Resumo: We calculate the equilibrium thermodynamic properties, percolation threshold, and cluster distribution functions for a model of associating colloids, which consists of hard spherical particles having on their surfaces three short-ranged attractive sites (sticky spots) of two different types, A and B. The thermodynamic properties are calculated using Wertheim's perturbation theory of associating fluids. This also allows us to find the onset of self-assembly, which can be quantified by the maxima of the specific heat at constant volume. The percolation threshold is derived, under the no-loop assumption, for the correlated bond model: In all cases it is two percolated phases that become identical at a critical point, when one exists. Finally, the cluster size distributions are calculated by mapping the model onto an effective model, characterized by a-state-dependent-functionality (f) over bar and unique bonding probability (p) over bar. The mapping is based on the asymptotic limit of the cluster distributions functions of the generic model and the effective parameters are defined through the requirement that the equilibrium cluster distributions of the true and effective models have the same number-averaged and weight-averaged sizes at all densities and temperatures. We also study the model numerically in the case where BB interactions are missing. In this limit, AB bonds either provide branching between A-chains (Y-junctions) if epsilon(AB)/epsilon(AA) is small, or drive the formation of a hyperbranched polymer if epsilon(AB)/epsilon(AA) is large. We find that the theoretical predictions describe quite accurately the numerical data, especially in the region where Y-junctions are present. There is fairly good agreement between theoretical and numerical results both for the thermodynamic (number of bonds and phase coexistence) and the connectivity properties of the model (cluster size distributions and percolation locus).
Peer review: yes
URI: http://hdl.handle.net/10400.21/668
ISSN: 0021-9606
Aparece nas colecções:ISEL - Física - Artigos



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