Dynamic coarse-graining of polymer systems using mobility functions. (26th April 2021)

• Record Type: Journal Article
• Authors: Li, Bing; Daoulas, Kostas; Schmid, Friederike
• Is Part Of: Journal of physics. Volume 33:Number 19(2021)
• Publication Date: 2021-04-26
• Subjects: polymer simulations -- coarse-graining -- dynamics -- friction -- dynamic density functional theory -- mobility function -- dynamic structure factor; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/1361-648X/abed1b
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: We propose a dynamic coarse-graining (CG) scheme for mapping heterogeneous polymer fluids onto extremely CG models in a dynamically consistent manner. The idea is to use as target function for the mapping a wave-vector dependent mobility function derived from the single-chain dynamic structure factor, which is calculated in the microscopic reference system. In previous work, we have shown that dynamic density functional calculations based on this mobility function can accurately reproduce the order/disorder kinetics in polymer melts, thus it is a suitable starting point for dynamic mapping. To enable the mapping over a range of relevant wave vectors, we propose to modify the CG dynamics by introducing internal friction parameters that slow down the CG monomer dynamics on local scales, without affecting the static equilibrium structure of the system. We illustrate and discuss the method using the example of infinitely long linear Rouse polymers mapped onto ultrashort CG chains. We show that our method can be used to construct dynamically consistent CG models for homopolymers with CG chain length N = 4, whereas for copolymers, longer CG chain lengths are necessary.