Second-order thermodynamic perturbation theory for the inverse patchy colloids

In this paper we propose extension of the second-order thermodynamic perturbation theory (TPT2) for the inverse patchy colloids (IPC) with arbitrary number of patches. The theory is used to study thermodynamical properties and liquid-gas phase behavior of the IPC model with one, two and three patches. To validate the accuracy of the TPT2 we compare theoretical predictions against corresponding results obtained by computer simulations. The theory is accurate for the one-patch version of the model at all values of the temperature and density studied and less accurate for two- and three-patch versions at lower temperature and higher density. Theoretical predictions for the critical temperature and density of the two- and three-patch IPC models are relatively accurate, however the overall shape of the theoretical phase diagram appears to be too narrow. No liquid-gas phase coexistence for the one-patch IPC model was found.