TY  - JOUR
AU  - Michalowsky, Julian
AU  - Zeman, Johannes
AU  - Holm, Christian
AU  - Smiatek, Jens
TI  - A polarizable MARTINI model for monovalent ions in aqueous solution
JO  - The journal of chemical physics
VL  - 149
IS  - 16
SN  - 1089-7690
CY  - Melville, NY
PB  - American Institute of Physics
M1  - FZJ-2019-02841
SP  - 163319
PY  - 2018
AB  - We present a new polarizable coarse-grained martini force field for monovalent ions, called refIon, which is developed mainly for the accurate reproduction of electrostatic properties in aqueous electrolyte solutions. The ion model relies on full long-range Coulomb interactions and introduces satellite charges around the central interaction site in order to model molecular polarization effects. All force field parameters are matched to reproduce the mass density and the static dielectric permittivity of aqueous NaCl solutions, such that experimental values are well-reproduced up to moderate salt concentrations of 2 mol/l. In addition, an improved agreement with experimentally measured ionic conductivities is observed. Our model is validated with regard to analytic solutions for the ion distribution around highly charged rod-like polyelectrolytes in combination with atomistic simulations and experimental results concerning structural properties of lipid bilayers in the presence of distinct salt concentrations. Further results regarding the coordination numbers of counterions around dilute poly(styrene sulfonate) and poly(diallyldimethylammonium) polyelectrolyte chains also highlight the applicability of our approach. The introduction of our force field allows us to eliminate heuristic scaling factors, as reported for previous martini ion models in terms of effective salt concentrations, and in consequence provides a better agreement between simulation and experimental results. The presented approach is specifically useful for recent martini attempts that focus on highly charged systems—such as models of DNA, polyelectrolytes or polyelectrolyte complexes—where precise studies of electrostatic effects and charge transport processes are essential.
LB  - PUB:(DE-HGF)16
C6  - pmid:30384758
UR  - <Go to ISI:>//WOS:000449103200021
DO  - DOI:10.1063/1.5028354
UR  - https://juser.fz-juelich.de/record/862547
ER  -