Wertheim perturbation theory: thermodynamics and structure of patchy colloids

Abstract

We critically discuss the application of the Wertheim’s theory to classes of complex associating fluids that can be today engineered in the laboratory as patchy colloids and to the prediction of their peculiar gas–liquid phase diagrams. Our systematic study, stemming from perturbative version of the theory, allows us to show that, even at the simplest level of approximation for the inter-cluster correlations, the theory is still able to provide a consistent and stable picture of the behaviour of interesting models of self-assembling colloidal suspension. We extend the analysis of a few cases of patchy systems recently introduced in the literature. In particular, we discuss for the first time in detail the consistency of the structural description underlying the perturbative approach and we are able to prove a consistency relationship between the valence as obtained from thermodynamics and from the structure for the one-site case. A simple analytical expression for the structure factor is proposed.

Keywords:

• colloidal suspensions
• Wertheim thermodynamic perturbation theory
• associating fluids
• structure of fluids

Acknowledgements

We are grateful to José Maria Cantista de Castro Tavares for correspondence and helpful comments. Giorgio Pastore acknowledges financial support by PRIN-COFIN 2010–2011 (contract 2010LKE4CC).

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

PRIN-COFIN 2010–2011 (Giorgio Pastore) (contract 2010LKE4CC).