Novel theory of entropy may solve materials design issues

A challenge in materials design is that in both natural and synthetic materials, volume can change with temperature. There are mechanical explanations for this phenomenon, but a general understanding of why it happens is lacking.

Penn State researchers came up with a theory to explain and predict Zentropy.

The concept of Zentropy is based on the idea of the disorder of a system when there is no energy applied to keep order. If no energy is put into keeping the playroom tidy, it quickly becomes a mess with toys all over the floor, a state of high entropy. The room will return to a state of order if energy is put in by cleaning up and organizing the room after the children leave.

When the volume increases due to higher temperature, the relationship between thermal expansion and the negative derivative of entropy is the same as when the pressure increases. This allows Zentropy theory to be able to predict the change of volume as a function of temperature at a multiscale level. Different parts of a system have their own entropy.

When we talk about the configuration entropy, it's only part of the system's entropy, according to the study's primary investigator.

According to the authors of the study, Zentropy may be able to predict anomalies of other physical properties of phases beyond volume. The system's responses to external stimuli are driven by the system's personality.

At all scales and below the scale of the state of investigation, materials have macroscopic functions. Predicting these functions is difficult because only one or a few microstates can be considered in a typical computational approach.

The challenge becomes acute in materials with multiple phase transitions, which are processes that convert matter from one state to another.

A nested formula for the entropy of complex multiscale systems is presented by the Zentropy theory.

There are different scales and you can stack them up with Zentropy theory. How do you cover the entire system with them? The Zentropy equation is about stacking them together. The partition function is the sum of all the scales.

This approach has been worked on by the lab for more than a decade.

The idea became very simple after we studied it.

Zentropy has the potential to change the way materials are designed, especially those that are exposed to higher temperatures. If the materials expand, these temperatures could cause problems.

It has the potential to enable the fundamental understanding and design of materials with emergent properties, such as new superconductors and new ferroelectric materials that could potentially lead to new classes of electronics.

Zentropy can be applied to multiple fields. The Zentropy theory has the potential to be applied to larger systems because of how entropy is present in all systems.

The other authors of the study are Yi Wang, research professor in materials science and engineering, and Shun-Li Zhang, research professor in materials science and engineering.

More information: Zi-Kui Liu et al, Zentropy Theory for Positive and Negative Thermal Expansion, Journal of Phase Equilibria and Diffusion (2022). DOI: 10.1007/s11669-022-00942-z Citation: Novel theory of entropy may solve materials design issues (2022, March 16) retrieved 17 March 2022 from https://phys.org/news/2022-03-theory-entropy-materials-issues.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.