The effect of comonomer composition on structural and surface properties of poly(ethylene-ran-propylene) thin films at various ethylene fraction were studied by Monte Carlo simulation of coarse-grained copolymer model on the second nearest neighbor diamond (2nnd) lattice. Intramolecular and intermolecular interactions of poly(ethylene-ran-propylene) were treated by the Rotational Isomeric State (RIS) model and the Lennard–Jones potential, respectively. The relative bead densities in the bulk region of films were increased as a function of ethylene fraction. Thin films become denser with sharper surface for copolymer with larger ethylene portion. End beads of copolymer chains were more abundant and the bonds tend to be oriented in the perpendicular direction near the free surface. More anisotropic orientation was observed for films with larger ethylene content. The radius of gyration component of copolymer chains in the perpendicular direction to the film surface was monotonically decreased, while the parallel component had no noticeable changed as a function of displacement from the film center of mass. Molecular size (components of the radius of gyration) and molecular shape (acylindricity) were apparently changed as a function of ethylene fraction. For molecular orientation, the largest axis was aligned preferably in parallel direction to the film surface, and relatively changed to more random isotropic orientation for less ethylene content.

共聚单体组成的聚的结构和表面特性（乙烯效果RAN研究了由粗粒共聚物模型蒙特卡罗模拟的第二最近邻金刚石（ -丙烯）在不同的乙烯馏分薄膜2nnd）晶格。分子内聚的分子间相互作用（乙烯跑-丙烯) 分别通过旋转异构状态 (RIS) 模型和 Lennard-Jones 势进行处理。薄膜主体区域中的相对珠密度作为乙烯分数的函数而增加。对于乙烯部分较大的共聚物，薄膜变得更致密，表面更锋利。共聚物链的端珠更丰富，并且键倾向于在自由表面附近的垂直方向上取向。对于乙烯含量较大的薄膜，观察到更多的各向异性取向。在垂直于薄膜表面的方向上，共聚物链的回转分量半径单调减小，而平行分量作为从薄膜质心位移的函数没有明显变化。分子大小（回转半径的组成部分）和分子形状（圆柱度）明显地作为乙烯分数的函数而改变。对于分子取向，最大轴优选与薄膜表面平行排列，并相对改变为更随机的各向同性取向以减少乙烯含量。