[gmx-users] Tacticity in polymer simulation

[Debadutta Prusty]

Hi everyone,

How does one go about preparing a polymer in a given state of tacticity?
>From what I understand about tacticity in polymers, it boils down to
coefficients(C1,C2,C3,C4,C5,C6) in Ryckaert-Bellemans function. If the
potential well is not deep enough, the polymer can easily transition from
an isotactic state into a syndiotactic state. The above coefficients for
dihedral angles are fixed for a particular force field. I found a few
papers on the effect of tacticity on properties of PAA,PMAA polymers where
the pattern is CA(R)-CB-CA(R'), where R is the acid group. They do not
mention whether it is the initial configuration that sets the tacticity of
a polymer.  I am not sure how to keep the relative orientations of two R
groups constant since they do not appear simultaneously in a dihedral
pattern (the dihedrals are R-CA-CB-CA or CA-CB-CA-R' ). Any help would be
appreciated.

Thanks,
Debadutta Prusty