Structure, thermodynamic properties, and phase diagrams of few colloids confined in a spherical pore

Journal Article · Sun Jun 28 00:00:00 EDT 2015 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.4923164· OSTI ID:22490854

Paganini, Iván E.; Pastorino, Claudio; Urrutia, Ignacio ^[1]

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1. Departamento de Física de la Materia Condensada, Centro Atómico Constituyentes, CNEA, Av.Gral. Paz 1499, 1650 Pcia. de Buenos Aires (Argentina)

We study a system of few colloids confined in a small spherical cavity with event driven molecular dynamics simulations in the canonical ensemble. The colloidal particles interact through a short range square-well potential that takes into account the basic elements of attraction and excluded-volume repulsion of the interaction among colloids. We analyze the structural and thermodynamic properties of this few-body confined system in the framework of inhomogeneous fluids theory. Pair correlation function and density profile are used to determine the structure and the spatial characteristics of the system. Pressure on the walls, internal energy, and surface quantities such as surface tension and adsorption are also analyzed for a wide range of densities and temperatures. We have characterized systems from 2 to 6 confined particles, identifying distinctive qualitative behavior over the thermodynamic plane T − ρ, in a few-particle equivalent to phase diagrams of macroscopic systems. Applying the extended law of corresponding states, the square well interaction is mapped to the Asakura-Oosawa model for colloid-polymer mixtures. We link explicitly the temperature of the confined square-well fluid to the equivalent packing fraction of polymers in the Asakura-Oosawa model. Using this approach, we study the confined system of few colloids in a colloid-polymer mixture.

• OSTI ID: 22490854
• Journal Information: Journal of Chemical Physics, Vol. 142, Issue 24; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
97 MATHEMATICAL METHODS AND COMPUTING
ADSORPTION
COLLOIDS
CORRELATION FUNCTIONS
DENSITY
INTERACTIONS
MIXTURES
MOLECULAR DYNAMICS METHOD
PARTICLES
PHASE DIAGRAMS
POLYMERS
SIMULATION
SPHERICAL CONFIGURATION
SQUARE-WELL POTENTIAL
THERMODYNAMIC PROPERTIES