Scientists crack the code on how gases stick to glass-like materials
Researchers have developed a simpler mathematical model to predict how gases are absorbed by glassy polymers and other disordered materials—a finding that could improve the design of gas separation membranes, storage systems, and industrial filters. The new approach reveals how materials transition between states and absorb different amounts of gas, offering engineers a faster way to optimize these widely used materials without extensive trial-and-error testing.
Originaltitel: Sorption of gases by disordered materials: A model based on the glass transition effect
<p>Disordered materials in the glassy state show different gas sorption properties compared to same materials in the liquid or rubbery state. The sorption enthalpy becomes more exothermic, and the absorbed amount is greater compared to the liquid or rubbery state. The sorption data are often treated in the literature using the dual-mode theory-a three-parameter sorption model. This work presents another approach where a gas sorption isotherm model for glassy materials is derived from thermodynamic consideration of glass transition properties. The model is particularly applicable for describing sorption data that obey Henry's law in the limit of the liquid or rubbery state. The model parameters correspond to physically meaningful characteristics of the system's glass transition. We demonstrate that experimental gas sorption data, when plotted as ln(P/C) vs C, exhibit linear behavior in both the rubbery and glassy states, enabling accurate determination of the glass transition point from isothermal data. Additionally, gas sorption in glassy disordered materials can be effectively described using a two-parameter function based on the Lambert W function.</p>