The Role of Surfactants in Mechanical Degradation of Drag-Reducing Polymers
Bibliographic record
Abstract
Turbulent drag reduction behavior of mixed polymer–surfactant systems (anionic polymer/cationic surfactant; nonionic polymer/cationic surfactant; nonionic polymer/anionic surfactant) was studied in a pipeline flow loop to explore the role of surfactants in mechanical degradation of polymers. The polymers investigated were nonionic polyethylene oxide (PEO) and anionic polyacrylamide (PAM). The surfactants studied were cationic octadecyltrimethylammonium chloride (OTAC) and anionic sodium dodecyl sulfate (SDS). The pipeline flow results obtained for PAM/OTAC mixtures support the idea that the coiling of polymer molecules does not protect the polymer molecules against shear degradation. The addition of oppositely charged cationic surfactant (OTAC) to anionic polymer (PAM) results in coiling of polymer molecules. The coiled polymer molecules undergo faster mechanical degradation than stretched polymer molecules. The addition of surfactant (cationic OTAC or anionic SDS) to nonionic polymer PEO increases the resistance of polymer molecules against shear degradation. This is reflected in the pipeline flow results. The effect is more significant for anionic surfactant (SDS) than for cationic surfactant (OTAC) especially at high concentrations of surfactant; the smaller size of the headgroup of anionic surfactant monomers allows them to have a greater influence on the polymer molecules. These results support the idea that extended polymer chains are more resistant to mechanical degradation as compared with coiled polymer molecules. The polymer chains undergo extension due to repulsion between the neighboring surfactant micelles attached to the backbone of the polymer chains.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".