Probing the adsorption behavior and molecular interactions of asphaltene subfractions at Water–Toluene/Heptol interface
Bibliographic record
Abstract
Asphaltene-stabilized water-in-oil (W/O) emulsions present significant challenges, contributing to corrosion and fouling in the oil industry. Previous studies have suggested that only a small fraction of asphaltenes is responsible for emulsion stabilization. In this work, whole asphaltenes were fractionated into interfacially active (IAA) and non-active (INAA) subfractions to better understand their interfacial behaviors. Dynamic interfacial tension (IFT), Langmuir–Blodgett trough, atomic force microscopy (AFM) imaging, and AFM drop probe technique were employed to explore the adsorption behavior, interfacial film properties, and interaction forces of IAA and INAA asphaltenes at the water-toluene/heptol interface. The effects of asphaltene subfraction concentrations and solvent aromaticity were systematically evaluated. IAA asphaltenes manifested higher interfacial diffusion coefficients and lower equilibrium interfacial tension at the water-toluene/heptol interface compared to INAA asphaltenes, indicating superior adsorption capabilities. IAA asphaltenes showed decreased interfacial diffusion coefficients at the water-heptol interface compared to toluene, while INAA asphaltenes displayed the opposite trend. Asphaltene subfractions formed protective layers at the water-toluene/heptol interface, sterically inhibiting water droplet coalescence. IAA asphaltenes form more rigid interfacial films than INAA asphaltenes, with the addition of n -heptane further increasing film rigidity. Quantitative force results demonstrated interfacial adhesion between IAA/INAA asphaltenes-adsorbed water droplets. Concentration of asphaltene subfractions and solvent aromaticity significantly influenced surface forces of emulsified water droplets by affecting the properties of asphaltene interfacial films. This work provides quantitative insights into the interfacial behaviors of asphaltene subfractions in both toluene and heptol, with implications for asphaltene-related interfacial phenomena in oil production.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".