二氧化硅纳米颗粒与表面活性剂协同稳定乳状液的机理：来自界面流变性质的见解

IF 5.2 2区化学 Q2 CHEMISTRY, PHYSICAL

Journal of Molecular Liquids Pub Date : 2025-10-08 DOI:10.1016/j.molliq.2025.128686

Derong Xu , Chenxi Wen , Liqing Wang , Wanxin Jiang , Wanli Kang

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引用次数: 0

摘要

表面活性剂驱油的关键机理之一是原油的乳化作用；然而，由传统表面活性剂溶液形成的乳剂往往不稳定。在表面活性剂溶液中加入纳米颗粒已成为提高乳液稳定性的有效策略。尽管如此，二氧化硅纳米颗粒与表面活性剂协同稳定乳状液的机理仍主要停留在宏观实验和理论假设阶段。在这项研究中，我们研究了二氧化硅纳米颗粒与表面活性剂联合稳定乳液的机理，重点研究了界面流变特性，使用了旋转滴界面膨胀流变仪。首先，进行了频率扫描和动态界面流变试验。然后考察了表面活性剂和纳米颗粒浓度对界面流变性能的影响。最后，通过宏观乳化实验和微观观察，分析和阐明了乳剂的稳定机理。频率扫描结果表明，界面粘弹性与频率在0.01 ~ 0.1 Hz范围内呈近似线性关系。动态流变学测量表明，界面弹性模量（E’）和粘性模量（E”）随时间急剧增加，并逐渐达到动态平衡。同时，油水界面张力（IFT）先减小后稳定，E′、E′′和IFT几乎同时达到平衡。随着表面活性剂浓度的增加，E′、E′′和IFT均先下降后趋于平稳。纳米颗粒本身并不能降低油水IFT，但当在0.05 wt% AES表面活性剂溶液中加入0.02 wt% SiO2纳米颗粒时，可以观察到IFT的轻微降低和E′的显著增加。宏观乳化实验表明，随着纳米颗粒浓度的升高，乳液的稳定性先升高后降低，在0.02 wt% SiO₂+ 0.05 wt% AES体系中稳定性最佳。显微图像证实，该系统产生更小的乳液液滴与更大的抗聚结。在微观观察和流变学数据的支持下，IFT降低和界面膜强度增强的综合结果为稳定化机制提供了新的见解。该研究为纳米颗粒/表面活性剂复合体系在复杂油藏提高采收率方面的应用提供了理论依据。

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Mechanisms of SiO₂ nanoparticles cooperating with surfactants to stabilize emulsions: insights from interfacial rheological properties

One of the key mechanisms in surfactant flooding is the emulsification of crude oil; however, emulsions formed by conventional surfactant solutions are often unstable. Incorporating nanoparticles into surfactant solutions has emerged as an effective strategy to enhance emulsion stability. Despite this, the mechanisms by which SiO₂ nanoparticles cooperate with surfactants to stabilize emulsions remain largely at the stage of macroscopic experiments and theoretical hypotheses.

In this study, we investigate the mechanisms of emulsion stabilization by SiO₂ nanoparticles in combination with surfactants, focusing on interfacial rheological properties using a spinning drop interfacial expansion rheometer. First, frequency sweep and dynamic interfacial rheology tests were conducted. Then, the effects of surfactant and nanoparticle concentrations on interfacial rheological properties were examined. Finally, macroscopic emulsification tests and microscopic observations of emulsions were performed to analyze and elucidate the stabilization mechanisms.

The frequency sweep results showed a near-linear relationship between interfacial viscoelasticity and frequency in the range of 0.01–0.1 Hz. Dynamic rheological measurements revealed that the interfacial elastic modulus (E') and viscous modulus (E") increased sharply over time and gradually reached dynamic equilibrium. Simultaneously, oil–water interfacial tension (IFT) decreased and then stabilized, with E', E", and IFT all reaching equilibrium at approximately the same time.

With increasing surfactant concentration, E', E", and IFT initially decreased and then plateaued. Nanoparticles alone did not reduce oil–water IFT, but when 0.02 wt% SiO₂ nanoparticles was added to a 0.05 wt% AES surfactant solution, a slight reduction in IFT and a significant increase in E' were observed. Macroscopic emulsification tests showed that emulsion stability first increased and then decreased with rising nanoparticle concentration, with optimal stability observed in the 0.02 wt% SiO₂ + 0.05 wt% AES system. Microscopic images confirmed that this system produced smaller emulsion droplets with greater resistance to coalescence.

The combined results of IFT reduction and enhanced interfacial film strength, supported by microscopic observations and rheological data, provide insight into the stabilization mechanisms. This study offers a theoretical basis for the application of nanoparticle/surfactant composite systems in enhancing oil recovery from complex reservoirs.

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来源期刊

Journal of Molecular Liquids 化学-物理：原子、分子和化学物理

CiteScore

10.30

自引率

16.70%

发文量

2597

审稿时长

78 days

期刊介绍： The journal includes papers in the following areas: – Simple organic liquids and mixtures – Ionic liquids – Surfactant solutions (including micelles and vesicles) and liquid interfaces – Colloidal solutions and nanoparticles – Thermotropic and lyotropic liquid crystals – Ferrofluids – Water, aqueous solutions and other hydrogen-bonded liquids – Lubricants, polymer solutions and melts – Molten metals and salts – Phase transitions and critical phenomena in liquids and confined fluids – Self assembly in complex liquids.– Biomolecules in solution The emphasis is on the molecular (or microscopic) understanding of particular liquids or liquid systems, especially concerning structure, dynamics and intermolecular forces. The experimental techniques used may include: – Conventional spectroscopy (mid-IR and far-IR, Raman, NMR, etc.) – Non-linear optics and time resolved spectroscopy (psec, fsec, asec, ISRS, etc.) – Light scattering (Rayleigh, Brillouin, PCS, etc.) – Dielectric relaxation – X-ray and neutron scattering and diffraction. Experimental studies, computer simulations (MD or MC) and analytical theory will be considered for publication; papers just reporting experimental results that do not contribute to the understanding of the fundamentals of molecular and ionic liquids will not be accepted. Only papers of a non-routine nature and advancing the field will be considered for publication.