Reentrant spinodals and the Speedy scenario in colloidal model systems

TL;DR

This paper investigates re-entrant spinodals and binodals in colloidal models, providing numerical and analytical evidence for their coexistence, which challenges traditional thermodynamic expectations.

Contribution

It presents the first in silico demonstration of models exhibiting both re-entrant spinodal and binodal, advancing understanding of complex phase behaviors.

Findings

Re-entrant spinodal observed in models.

Re-entrant binodal also identified.

Models demonstrate coexistence of re-entrant features.

Abstract

A re-entrant gas-liquid spinodal was proposed as a possible explanation of the apparent divergence of the compressibility and specific heat on supercooling water. Such a counter intuitive possibility, e.g. a liquid that becomes unstable to gas-like fluctuations on cooling at positive pressure, has never been observed, neither in real substances nor in off-lattice simulations. More recently, such re-entrant scenario has been dismissed on the premise that the re-entrant spinodal would collide with the gas-liquid binodal in the pressure-temperature plane. Here we study, numerically and analytically, two previously introduced one-component patchy particle models that both show (i) a re-entrant spinodal and (ii) a re-entrant binodal, providing a neat in silico (and in charta) realization of such unconventional thermodynamic scenario.