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Molecular dynamics approach to the structural characterization and transport properties of poly(acrylonitrile)/N,N-dimethylformamide solutions

journal contribution
posted on 01.07.2016, 00:00 authored by Weimin Gao, Fenghua SheFenghua She, Jane ZhangJane Zhang, Ludovic DumeeLudovic Dumee, K L Tung, Peter HodgsonPeter Hodgson, Lingxue KongLingxue Kong
Poly(acrylonitrile) (PAN) in N,N-dimethylformamide (DMF) is a popular solution for producing large variety of polymer products. To precisely describe the behaviours of PAN and DMF in the synthesis processes, it is significant to call for more details about the structure, some thermodynamic and dynamical properties of PAN-DMF solutions. A PAN-DMF solution was simulated via molecular dynamics with an all-atom OPLS type potential in both the NPT and NVT ensembles. The simulation results were evaluated with quantum mechanical calculations (MP2/6-311 ++G(d,p) and counterpoise procedure) and were compared with available experimental results. The liquid structure was illustrated with pair correlation functions and transport and dynamics properties were calculated with the mean-square displacements MSD and the velocity autocorrelation functions. The strong H-bonds of C≡N « H-C=O, CH » O=C-H and CH2 O=C-H, with distances of 2.55 Å, 2.55 Å and 2.65 Å, respectively, were found. The largest interaction energy of - 7.157 kcal/mol between DMF molecules and PAN molecules was found at 4.9 Å center-of-mass distance. A potential profile of intermolecular interaction of DMF with PAN along the interaction distance was presented, clearly showing an increase of DMF vaporisation heat when it getting close to PAN molecules. This provided very useful information to analyse the vaporisation behaviours of DMF at the microscopic level, which is essential to comprehensively understand molecular rearrangements towards the design of synthetic processes. The impact of the presence of the PAN on the DMF solution properties were also benchmarked with pure DMF solution.

History

Journal

Journal of molecular liquids

Volume

219

Pagination

45 - 53

Publisher

Elsevier

Location

Amsterdam, The Netherlands

ISSN

0167-7322

Language

eng

Publication classification

C Journal article; C1 Refereed article in a scholarly journal

Copyright notice

2016, Elsevier