目的:具有不同界面行为的沥青烯亚组分可能在稳定油水乳液中起不同的作用。
方法:在这项工作中,将整个沥青质分为界面活性沥青质(IAA)和界面非活性沥青质(INAA)。采用先进的纳米机械技术,我们探索了构图,形态学,尺寸,吸附,以及IAA和INAA的界面行为。
结果:IAA表现出高且不均匀分布的氧含量,区别于INAA。在甲苯中,IAA和INAA的直径约为60nm和6nm,分别。当不可逆地吸附在云母表面时,IAA和INAA薄膜的厚度测量为~5.5nm或1nm,分别;而在甲苯溶液中,IAA和INAA的薄膜厚度达到〜46nm和3.1nm,分别。IAA表现出优越的界面活性,以及与水-甲苯界面处的INAA相比的弹性/粘性模量。定量的表面力测量表明,IAA稳定水滴在甲苯中的浓度仅为10mg/L,而INAA需要100mg/L的较高浓度。这项工作首次全面研究了沥青质亚馏分的吸附和界面行为,并为乳液的沥青质稳定机理提供了有用的见解。
OBJECTIVE: Asphaltenes subfractions with distinct interfacial behaviors may play different roles in stabilizing oil-water emulsions.
METHODS: In this work, whole asphaltenes were separated into interfacially active asphaltenes (IAA) and interfacially non-active asphaltenes (INAA). Employing advanced nanomechanical techniques, we have explored the compositions, morphologies, sizes, adsorption, and interfacial behaviors of IAA and INAA.
RESULTS: IAA exhibits a high and unevenly distributed oxygen content, distinguishing it from INAA. In toluene, the diameters of IAA and INAA are about 60 nm and 6 nm, respectively. When adsorbed irreversibly on mica surfaces, the thickness of the IAA and INAA film was measured at ∼5.5 nm or 1 nm, respectively; while in a toluene solution, the film thickness reached ∼46 nm and 3.1 nm for IAA and INAA, respectively. IAA demonstrates superior interfacial activity, and elastic/viscous moduli compared to INAA at the water-toluene interface. Quantified surface force measurements reveal that IAA stabilizes water droplets in toluene at a concentration of only 10 mg/L, while INAA requires a higher concentration of 100 mg/L. This work provides the first comprehensive investigation into the adsorption and interfacial behaviors of asphaltene subfractions and provides useful insights into the asphaltenes-stabilization mechanism of emulsions.