Coarse-Grained Modeling for Macromolecular Chemistry - Multiscale Molecular Methods in Applied Chemistry - page 308

one IBI potential over the entire temperature range of interest (300-600 K), and all
properties investigated showed good agreement with experimental and atomistic
results. In contrast, for PS, by using PS-MS2 the analysis of the intramolecular
distribution of parameters such as distances and angles, as well as the RDFs,
showed that the PS IBI force field can be confidently applied only in a small
temperature range (~50 K) around the optimization temperature. Within this
range, the density and the static properties of the PS bulk are in reasonable
agreement with experimental and atomistic values; however, for temperatures
further from the optimization point, the IBI potential cannot correctly reproduce
the behavior of the polymer. By changing the mapping scheme from PS-MS2 to
PS-MS1, the CG potential turned out to be very robust and transferable between
different temperatures (over a range of 100 K) [ 18 ]. Figure 5 shows the density
changes with the temperature for the atomistic and CG simulations of PS using
PS-MS1 and PS-MS2. These results show that the transferability of the CG force
field developed by the IBI method depends strangely on the location of the
superatom within the real monomer, the number of degrees of freedom removed
during the CG procedure, and the polymer under investigation.
Concerning the transferability of CG force field for PA-66 to different tempera-
tures, we explored different thermodynamic and structural properties of the system
at different temperatures [ 15 , 16 , 61 ]. The hydrogen bonding is one of the intermo-
lecular interactions that most influences the dynamics of molecular systems, being
responsible for the structure, function, and dynamics of many chemical systems
from inorganic to biological compounds [ 62 ]. Due to the simplification of the CG
Fig. 5 Density change with the temperature for the atomistic and CG simulations of PS using
PS-MS1 and PS-MS2 (see Fig. 1c ). The density values have been normalized with respect to the
reference value at 500 K