To study the effect of electrostatic interaction on the interface and mechanical properties of nano-composites, two kinds of silica nanoparticles with positive and negative charges were prepared and introduced into waterborne polyurethane (WPU) emulsion with negative charges to prepare composite emulsion and film. Molecular dynamics simulation and instrumental characterization were used to investigate the properties of nanoparticles and hybrid films. Molecular dynamics simulation results showed that WPU/SiO₂₍₊₎ nanocomposite demonstrated higher interfacial free energy, lower free volume fraction and diffusion coefficient than those of WPU/SiO₂₍₋₎ nanocomposite. The mechanical properties of the composite films indicated that there is no positive effect on the mechanical properties as the charges of SiO₂ and WPU keep the same. Therefore, the mechanical properties of the composite films can be effectively enhanced by introducing positively charged SiO₂, and the optimized introduction amount is 1 %. SEM images of the cross-section for the film show that SiO₂₍₊₎ exhibits higher interfacial interaction strength with the WPU matrix than SiO₂₍₋₎. Accordingly, molecular dynamics simulation and instrumental analysis afford similar results.

为研究静电相互作用对纳米复合材料界面和力学性能的影响，制备了两种带正负电荷的二氧化硅纳米粒子，并将其引入带负电荷的水性聚氨酯（WPU）乳液中，制备复合乳液和薄膜。分子动力学模拟和仪器表征用于研究纳米颗粒和混合薄膜的性质。分子动力学模拟结果表明，与WPU/SiO 2( - )相比，WPU/SiO _{2 ( + )}纳米复合材料具有更高的界面自由能、更低的自由体积分数和扩散系数。纳米复合材料。_{复合薄膜的力学性能表明，由于SiO 2}和WPU的电荷保持不变，对力学性能没有积极影响。因此，引入带正电的SiO ₂可以有效提高复合薄膜的力学性能，优化的引入量为1%。薄膜横截面的 SEM 图像显示 SiO ₂₍₊₎与 WPU 基体的界面相互作用强度高于 SiO _{2( - )}。因此，分子动力学模拟和仪器分析提供了类似的结果。