Surface Enrichment of Poly(trifluorovinyl ether)s in Polystyrene Blends
Bibliographic record
Abstract
Surface modification can be achieved with polymer blends when one component of the system is more surface active than the others. Numerous factors affect the interfacial properties, including the type and concentration of polymers, the solvent, and the interface. Blends of polystyrene (PS) and poly(trifluorovinyl ether) (PTFVE) having a fluorocarbon backbone and an oligoether pendant group were cast as films from chloroform or toluene. The air−polymer interface was investigated and found to be enriched with PTFVE at very low bulk concentrations (<1 wt %) as determined by XPS and contact angle analysis. Both surface fluorine and oxygen increased with bulk PTFVE content. Interestingly, PTFVE-enriched surfaces were increasingly hydrophilic with PTFVE content, indicating that oligoether groups were dominant at the outermost layer. This observation was confirmed by angle-resolved XPS and ToF SIMS. AFM of PTFVE cast on mica indicated the presence of large aggregates on the order of 200 nm in diameter. We hypothesize that PTFVE in PS/PTFVE blends form similar structures at the interface, with aggregates having PTFVE cores and oligoether coronas, thereby accounting for oligoether pendant groups, and not fluorocarbon backbone, at the air−polymer interface. The nature of the solvent influenced the surface properties of the blends; films cast from toluene, which is a better solvent for PS than chloroform, required greater PTFVE content in the bulk for surface activity than those cast from chloroform. Furthermore, the type of PTFVE used affected surface activity and the resulting surface hydrophilicity.
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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".