Chemical Engineering Seminar

Statistical thermodynamics, which explains gases, liquids and solids in equilibrium, does not provide a fundamental microscopic understanding of matter in non-equilibrium states.  Yet, most amorphous solids (like glasses and gels), although highly ubiquitous and apparently stable, are not in thermodynamic equilibrium, since their properties may exhibit aging and do depend on their preparation protocol.  For example, in a variety of colloidal systems, the interplay between phase separation and the solidification of the condensed phase leads to the formation of amorphous sponge-like non-equilibrium bicontinuous materials.  In this work we demonstrate that the non-equilibrium self-consistent generalized Langevin equation (NE-SCGLE) theory [1,2] predicts, in remarkable detail, the main kinetic features observed in the irreversible structural and dynamical relaxation of these liquids along their kinetic pathway to these amorphous states.  For shallow quenches the predicted scenario coincides with Cahn-Hilliard-Cook's theory of the early stage of spinodal decomposition, thus allowing for full phase separation.  For deeper quenches, instead, the dynamic arrest occurs at a much earlier stage, leading to the formation of the referred amorphous materials.

[1] P.E. Ramirez-Gonzalez and M. Medina-Noyola, Phys. Rev. E. 82, 061503 (2010).

[2] J.M. Olais-Govea, L. Lopez-Flores, and M. Medina-Noyola, J. Chem. Phys. 143, 174505 (2015).