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

作者：Gao Weimin^*; She Fenghua; Zhang Juan; Dumee Ludovic F; Tung Kuo Lun; Hodgson Peter D; Kong Lingxue^*

来源：Journal of Molecular Liquids, 2016, 219: 45-53.

DOI：10.1016/j.molliq.2016.03.017

• Polyacrylonitrile
• N,N-dimethylformamide
• Structural conformation
• Intermolecular interaction
• Transport property
• Molecular mechanics

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 center dot center dot center dot H-C=O, CH center dot center dot center dot O=C-H and CH2 center dot center dot center dot O=C-H with distances of 2.55 angstrom, 2.55 angstrom and 2.65 angstrom, respectively, were found. The largest interaction energy of-7.157 kcal/mol between DMF molecules and PAN molecules was found at 4.9 angstrom 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.

• 出版日期2016-7
• 单位迪肯大学