Gooneie Ali, Gonzalez-Gutierrez Joamin, Holzer Clemens
Chair of Polymer Processing, Montanuniversitaet Leoben, Leoben 8700, Austria.
Polymers (Basel). 2016 Oct 14;8(10):361. doi: 10.3390/polym8100361.
The interactions and conformational characteristics of confined molten polypropylene (PP) chains between ferric oxide (Fe₂O₃) substrates were investigated by molecular dynamics (MD) simulations. A comparative analysis of the adsorbed amount shows strong adsorption of the chains on the high-energy surface of Fe₂O₃. Local structures formed in the polymer film were studied utilizing density profiles, orientation of bonds, and end-to-end distance of chains. At interfacial regions, the backbone carbon-carbon bonds of the chains preferably orient in the direction parallel to the surface while the carbon-carbon bonds with the side groups show a slight tendency to orient normal to the surface. Based on the conformation tensor data, the chains are compressed in the normal direction to the substrates in the interfacial regions while they tend to flatten in parallel planes with respect to the surfaces. The orientation of the bonds as well as the overall flattening of the chains in planes parallel to the solid surfaces are almost identical to that of the unconfined PP chains. Also, the local pressure tensor is anisotropic closer to the solid surfaces of Fe₂O₃ indicating the influence of the confinement on the buildup imbalance of normal and tangential pressures.
通过分子动力学（MD）模拟研究了受限的熔融聚丙烯（PP）链与氧化铁（Fe₂O₃）基底之间的相互作用和构象特征。对吸附量的比较分析表明，链在Fe₂O₃的高能表面上有强烈吸附。利用密度分布、键的取向和链的端到端距离研究了聚合物薄膜中形成的局部结构。在界面区域，链的主链碳-碳键优选沿平行于表面的方向取向，而带有侧基的碳-碳键则显示出略微垂直于表面取向的趋势。基于构象张量数据，链在界面区域垂直于基底方向被压缩，而它们倾向于在相对于表面的平行平面中变平。键的取向以及链在平行于固体表面的平面中的整体变平情况与非受限PP链几乎相同。此外，靠近Fe₂O₃固体表面的局部压力张量是各向异性的，这表明受限对法向和切向压力积累不平衡的影响。
