There are now two additional PPFs available in this software that are
based on the Flory polymer swelling model, and the McKenzie-Domb model
that takes on the more general form of the equation above. The weight
on the distribution function (
) is a
partial measure of the self-avoidance of the polymer chain. The
effect is to cause the chain to expand. We can estimate the
root-mean-square separation distance of the polymer chain from
from the following thermodynamic relationship
where
is the entropy with
corresponding to Eqn (1). Solving Eq. (6) for
yields
Thus, when , the rms for
must decrease and
likewise, for
, the rms tends to increase
exponentially. On the other hand,
only shows a direct weight
on
for any fixed
. Ultimately, both
and
show a complex interdependence on the excluded volume. To make
intelligent physical estimates, you will need to consider this
behavior in your choice of parameters.
Increasing the size of your excluded volume will tend to encourage your stems to form shorter domains. Likewise, compacting the size of the polymer to a globular structure will encourage longer stems. Understanding the solvent environment is very important in such cases.