Friction at the Liquid/Liquid Interface of Two Immiscible Polymer Films
Bibliographic record
Abstract
We studied the friction between two immiscible polymer melts of polybutadiene (PBD) and polydimethylsiloxane (PDMS). Polymer films (100-300 nm thick) were coated onto smooth mica substrates, and then were brought into contact and sheared (slid) to and fro in a surface forces apparatus (SFA). Stop-wait-start experiments were also carried out at different sliding velocities to investigate the characteristic relaxation times of the interdigitation and disinterdigitation processes at both the static and shearing interfaces. By virtue of their limited interdigitation/interpenetration across the contact interface, immiscible polymers never fully coalesce into a continuous homogeneous material. This affects both their dynamic adhesion and friction forces. The immiscible interface exhibits various "characteristic" parameters such as its static and dynamic widths and at least two relaxation times: the static interpenetration time and the velocity adaptation time. The interfacial width saturates at some small but finite value, resulting in Stribeck-like behavior for the friction force as a function of the sliding velocity, characterized by F having a minimum value at some characteristic sliding velocity V. The presence of solvents at the immiscible interface can have a dramatic effect on the friction or lubrication forces. The implications of the results regarding the depth and dynamics of interdigitation and interpenetration of immiscible chains across an interface are discussed in relation to the adhesion, friction, and strength of polymer composites and the coalescence of immiscible droplets.
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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 | 0.001 |
| 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 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".