Nanoparticles are of interest in recent oil production process due to their potential to wettability alteration, but not interfacially active at the crude oil-water interface. Stability loss in brine environment, where nanoparticles tend to aggregate, is another issue for field implementation. Hence, recent challenge is to functionalize nanoparticles that are interfacially active and still stabilized in brine. The current study fabricated and characterized the polyvinylpyrrolidone-coated silica composite nanoparticles for their interfacial activity at the crude oil-water interface. Reduction in oil-water interfacial tension was observed and more dramatic with increasing particle concentration, confirming particle adsorption performance. In low-salinity brine (2000 ppm NaCl), the composite particles remained stabilized with weakened electrostatic force between particle and crude oil surfaces, while their size was smaller due to polymer shell dehydration. These led to faster diffusion rate than in Milli-Q water, which affected the rate of change in oil-water/brine interfacial tension, with the early-stage adsorption being a diffusion-controlled in both fluids. At equivalent particle concentration, the oil-water interfacial tensions in brine were lower than those of Milli-Q water (by ∼2 mN/m), with interfacial coverage of the particles at the interface was found to be higher in the brine. Such difference is attributed to a weaker repulsive force between particle and the interface, induced by surface charge screening that is only present in brine. The study has demonstrated the potential use of polymer-coated nanoparticles as suitable additives for use in oil recovery, which can be used concurrently with low-salinity brine as a combined fluid. While both chemicals are known to construct disjoining pressure for wettability alteration, advantage of using interfacially active nanoparticles is additional mechanism to enhance oil recovery, i.e. reducing the oil-water interfacial tension, which unfunctionalized particles could not contribute.

纳米颗粒在最近的石油生产过程中受到关注，因为它们具有改变润湿性的潜力，但在原油-水界面没有界面活性。盐水环境中的稳定性损失（纳米颗粒倾向于聚集）是现场实施的另一个问题。因此，最近的挑战是功能化具有界面活性且仍稳定在盐水中的纳米颗粒。目前的研究制造并表征了聚乙烯吡咯烷酮包覆的二氧化硅复合纳米粒子在原油-水界面的界面活性。观察到油水界面张力的降低，并且随着颗粒浓度的增加更为显着，证实了颗粒的吸附性能。在低盐度盐水（2000 ppm NaCl）中，复合颗粒保持稳定，颗粒和原油表面之间的静电力减弱，而由于聚合物壳脱水，它们的尺寸更小。这些导致比在 Milli-Q 水中更快的扩散速率，这影响了油-水/盐水界面张力的变化速率，早期吸附在两种流体中都是扩散控制的。在相同的颗粒浓度下，盐水中的油水界面张力低于 Milli-Q 水（约 2 mN/m），界面处颗粒的界面覆盖率在盐水中更高。这种差异归因于颗粒与界面之间较弱的排斥力，这是由仅存在于盐水中的表面电荷筛选引起的。该研究证明了聚合物涂层纳米粒子作为用于采油的合适添加剂的潜在用途，它可以与低盐度盐水同时用作混合流体。虽然已知这两种化学物质都会构建分离压力以改变润湿性，但使用界面活性纳米颗粒的优势是提高采收率的额外机制，即降低油水界面张力，而未功能化的颗粒无法发挥作用。

纳米颗粒在最近的石油生产过程中受到关注，因为它们具有改变润湿性的潜力，但在原油-水界面没有界面活性。盐水环境中的稳定性损失（纳米颗粒倾向于聚集）是现场实施的另一个问题。因此，最近的挑战是功能化具有界面活性且仍稳定在盐水中的纳米颗粒。目前的研究制造并表征了聚乙烯吡咯烷酮包覆的二氧化硅复合纳米粒子在原油-水界面的界面活性。观察到油水界面张力的降低，并且随着颗粒浓度的增加更为显着，证实了颗粒的吸附性能。在低盐度盐水（2000 ppm NaCl）中，复合颗粒保持稳定，颗粒和原油表面之间的静电力减弱，而由于聚合物壳脱水，它们的尺寸更小。这些导致比在 Milli-Q 水中更快的扩散速率，这影响了油-水/盐水界面张力的变化速率，早期吸附在两种流体中都是扩散控制的。在相同的颗粒浓度下，盐水中的油水界面张力低于 Milli-Q 水（约 2 mN/m），界面处颗粒的界面覆盖率在盐水中更高。这种差异归因于颗粒与界面之间较弱的排斥力，这是由仅存在于盐水中的表面电荷筛选引起的。该研究证明了聚合物涂层纳米粒子作为用于采油的合适添加剂的潜在用途，它可以与低盐度盐水同时用作混合流体。虽然已知这两种化学物质都会构建分离压力以改变润湿性，但使用界面活性纳米颗粒的优势是提高采收率的额外机制，即降低油水界面张力，而未功能化的颗粒无法发挥作用。