科研之友
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摘要
The surface absorption energy and the absorbed chains' conformation were investigated by molecular dynamics( MD) simulations using compass force field and NVT ensemble model, in the case of poly(vinylidene fluoride) ( PVDF polychlorotrifluoroethylene ( PCTFE) and their copolymers being absorbed on the crystal surface of 1 3 5-triamino-2,4,6-trinitobenzene (TATB). The results show that the absorption exothermic effect appeared as the distance between polymer chains and the TATB crystal surface shorten to less than 0.8 nm. The absorption effect of PVDF was string on the TATB crystal surface and it was reverse of PCTFE. MD simulations of alternative copolymers and random copolymers, with VDF and CTFE monomer ratio varying with 1: 1, 1: 2, 1: 3 and 1: 4 respectively, were carried out. The results indicte that the composition and serial structure of polymer chain influenced significantly tie chain's spatial conformations and its absorption behavior on TATB crystal surface. Especially, the alternative copolymer with the monomer ratio of 1: 2 showed the best absorption effect, attaching TATB crystal surface with train-conformations. As CTFE fraction increased, the stiffness of the copolymer was also increased, while he absorption ability and absorption energy decreased gradually with more tall and loop conformations formed.
