TY - JOUR
T1 - Development and Testing of an All-Atom Force Field for Diketopyrrolopyrrole Polymers with Conjugated Substituents
AU - Sundaram, Vivek
AU - Lyulin, Alexey V
AU - Baumeier, Björn
PY - 2020/12/3
Y1 - 2020/12/3
N2 - We develop an all-atom force field for a series of diketopyrrolopyrrole polymers with two aromatic pyridine substituents and a variable number of π-conjugated thiophene units in the backbone (DPP2PymT), used as donor materials in organic photovoltaic devices. Available intrafragment parameterizations of the individual fragment building blocks are combined with interfragment bonded and nonbonded parameters explicitly derived from density functional theory calculations. To validate the force field, we perform classical molecular dynamics simulations of single polymer chains with m = 1, 2, 3 in good and bad solvents and of melts. We observe the expected dependence of the chain conformation on the solvent quality, with the chain collapsing in water, and swelling in chloroform. The glass-transition temperature for the polymer melts is found to be in the range of 340-370 K. Analysis of the mobility of the conjugated segments in the polymer backbone reveals two relaxation processes: a fast one with a characteristic time at room temperature on the order of 10 ps associated with nearly harmonic vibrations and a slow one on the order of 100 ns associated with temperature-activated cis-trans transitions.
AB - We develop an all-atom force field for a series of diketopyrrolopyrrole polymers with two aromatic pyridine substituents and a variable number of π-conjugated thiophene units in the backbone (DPP2PymT), used as donor materials in organic photovoltaic devices. Available intrafragment parameterizations of the individual fragment building blocks are combined with interfragment bonded and nonbonded parameters explicitly derived from density functional theory calculations. To validate the force field, we perform classical molecular dynamics simulations of single polymer chains with m = 1, 2, 3 in good and bad solvents and of melts. We observe the expected dependence of the chain conformation on the solvent quality, with the chain collapsing in water, and swelling in chloroform. The glass-transition temperature for the polymer melts is found to be in the range of 340-370 K. Analysis of the mobility of the conjugated segments in the polymer backbone reveals two relaxation processes: a fast one with a characteristic time at room temperature on the order of 10 ps associated with nearly harmonic vibrations and a slow one on the order of 100 ns associated with temperature-activated cis-trans transitions.
UR - http://www.scopus.com/inward/record.url?scp=85097210749&partnerID=8YFLogxK
U2 - 10.1021/acs.jpcb.0c06787
DO - 10.1021/acs.jpcb.0c06787
M3 - Article
C2 - 33211500
SN - 1520-6106
VL - 124
SP - 11030
EP - 11039
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
IS - 48
ER -