published in the recent journal of phase
equilibria and diffusion a team of penn
state researchers has developed a theory
of entropy to explain and then predict
the particular behavior of materials
xentropy
you may ask what is this entropy
by checking this entropy word online you
may think that xantropy comes from xenon
entropy where the terms n is derived
from buddhism doctrine that
enlightenment can be obtained through
direct intuitive insight
however this entropy is not that's
entropy simply put here xentropy is a
play on entropy here this entropy theory
integrates entropy at multi-scale levels
the term z is suggested by scientists
for the partition function with the
meaning of some over states that is the
zoo stands some in german coined by
physicist max planck
you may ask why does entropy
it is well known that entropy is a
concept central to the second law of
thermodynamics that expresses the
measure of the disorder of a system that
occurs over some time when there is no
energy applied to keep order in the
system a challenge in materials design
is that in both natural and man-made
materials volume sometimes decreases or
increases with increasing temperature
while some specific materials have
mechanical explanations for this
phenomenon a general understanding of
why this sometimes happens remains
lacking
scientists have developed this xantropy
theory to explain and predict such
materials behavior
think of a playroom in a preschool if no
energy is put into keeping it tidy it
quickly becomes disordered with toys all
over the floor a state of high entropy
if energy is put in via cleaning up and
organizing the room once the children
leave the room returns to a state of
order and low entropy
xentropy theory notes that the
thermodynamic relationship of thermal
expansion when the volume increases due
to the higher temperature is equal to
the negative derivative of entropy
concerning pressure that is the entropy
of most material systems decreases with
an increase in pressure
this enables entropy theory to predict
the change of volume as a function of
temperature at a multiscale level
meaning the different scales within a
system
every state of matter has its own
entropy and various parts of a system
have their own entropy
so that is what this entropy equation is
about stacking them together it creates
a partition function that is the sum of
all the entropy scales professor of
materials science and engineering and
primary investigator in the study
sequilu said when we talk about the
configuration entropy different ways
particles rearrange within a system that
entropy is only part of the system's
entropy
so you have to add the entropy of
individual components of that system
into the equation and then you consider
the different scales the universe the
earth the people the materials these are
different scales within different
systems
it is believed that centropy may be able
to predict anomalies of other physical
properties of phases beyond volume this
is because the responses of a system to
external stimuli are driven by entropy
macroscopic functionalities of materials
stem from assemblies of microscopic
states at all scales and below the scale
of the macroscopic state of the
investigation
these functionalities are challenging to
predict because only one or a few
microstates can be considered in a
typical computational approach such as
the predictive from the beginning
calculations which help determine the
fundamental properties of materials
this challenge becomes acute in
materials with multiple phase
transitions which are processes that
convert matter from one state to another
such as vaporization of a liquid this is
often where the most transformative
functionalities exist such as
superconductivity and giant
electromechanical response centropy
theory stacks these different scales
into an entropy theory that encompasses
the different elements of an entire
system presenting a nested formula for
the entropy of complex multi-scale
systems
you have these different scales and you
can stack them up with zentropy theory
lou said for example atoms has a
vibrational property that's low scale
then you have electronic interaction
that even lower scale so now how do you
stack them together to cover the entire
system so that is what this entropy
equation is about stacking them together
it creates a partition function that is
the sum of all the entropy scales
this entropy theory has the potential to
be applied to larger systems because
entropy drives changes in all systems
whether they are black holes planets
societies or forests this approach has
been something lew's lab has worked on
for more than 10 years and five
different published studies the idea
actually became very simple after we
studied it and understood it zentropy
can potentially change the way materials
are designed especially those that are
part of systems that are exposed to
higher temperatures these temperatures
given thermal expansion could cause
issues if the materials expand
this 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 also other applications such
as designing better structural materials
that withstand higher temperatures are
also possible while there are benefits
for society researchers could apply
entropy to multiple fields this is
because of how entropy is present in all
systems
this entropy theory has the potential to
be applied to larger systems because
entropy drives changes in all systems
whether they are black holes planets
societies or forests