Molecular Interactions between a Biodegradable Demulsifier and Asphaltenes in an Organic Solvent
Bibliographic record
Abstract
A surface forces apparatus (SFA) was used to measure the intermolecular forces between a biodegradable demulsifier (ethyl cellulose, EC) and asphaltenes immobilized individually on molecularly smooth mica surfaces in an organic solvent. A steric repulsion on approach between the immobilized EC layers and asphaltenes was measured despite strong adhesion ( F ad / R ≈ −2 mN/m; W ad = 0.42 mJ/m 2 ) during retraction. The measured adhesion was attributed to the interpenetration and tangling of aliphatic branches of swollen asphaltenes and solvated chains of EC macromolecules. Competitive adsorption of EC on/in immobilized asphaltene layers was confirmed by combining SFA force measurements and atomic force microscopy (AFM) imaging. Following the injection of EC-in-toluene solution, an immediate (<5 min) increase in the confined layer thickness of the immobilized asphaltene layers was measured. Irreversibly adsorbed asphaltenes were displaced by EC macromolecules through binding with unoccupied surface sites on mica, followed by the spreading of EC across the mica substrate due to increased surface activity governed by the higher number of hydroxyl groups per EC molecule. AFM imaging confirmed that the increase in confined layer thickness resulted from the formation of larger asphaltene aggregates/clusters protruding from the mica substrate. Molecular level topographical images showed that the asphaltenes were not resolvated in the organic phase but self-associated as the EC macromolecules spread across the hydrophilic mica substrate. The results from this study provide not only fundamental insights into the basic interaction mechanisms of asphaltenes with EC macromolecules as a demulsifier in organic media but also directions toward enhancing demulsification of water-in-oil emulsions.
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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".