Effect of mesoscopic fluctuations on equation of state in cluster-forming systems

Abstract

Equation of state for systems with particles self-assembling into aggregates is derived within a mesoscopic theory combining density functional and field-theoretic approaches. We focus on the effect of mesoscopic fluctuations in the disordered phase. The pressure -- volume fraction isotherms are calculated explicitly for two forms of the short-range attraction long-range repulsion potential. Mesoscopic fluctuations lead to an increased pressure in each case, except for very small volume fractions. When large clusters are formed, the mechanical instability of the system is present at much higher temperature than found in mean-field approximation. In this case phase separation competes with the formation of periodic phases (colloidal crystals). In the case of small clusters, no mechanical instability associated with separation into dilute and dense phases appears.

16 pages, 14 figures

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Cited by in corpus (7)

• Periodic ordering of clusters in a one-dimensional lattice model
• Combined density functional and Brazovskii theories for systems with spontaneous inhomogeneities
• Correct scaling of the correlation length from a theory for concentrated electrolytes
• Effects of fluctuations on correlation functions in inhomogeneous mixtures
• Self-consistent theory for inhomogeneous systems with mesoscopic fluctuations
• Density functional theory for systems with mesoscopic inhomogeneities
• Correlation functions in mixtures with energetically favoured nearest-neighbours of different kind: a size-asymmetric case