Enantiomeric Polylactides at the Air−Water Interface: π−<i>A</i> Isotherms and PM-IRRAS Studies of Enantiomers and Their Blend
Bibliographic record
Abstract
The surface pressure−area (π− A ) isotherms of enantiomeric polylactides and their equimolar blend reveal differences in the appearance of features and compression rate effects. Surface potential data indicate that the poly( l -lactide) monolayer interacts differently than the 50:50 poly( l -lactide)/poly( d -lactide) blend film with the water subphase. In the case of the 50:50 blend at 25 °C, compression−expansion experiments confirm that the change in the monolayer is irreversible within the time frame of the experiment. In the poly( l -lactide) case, hysteresis is also observed, but the film readily reverts to its original state. Infrared spectra of the polymer monolayers at the air−water interface were obtained using the polarization−modulation infrared reflection−absorption spectroscopy (PM-IRRAS) technique. PM-IRRAS spectra of a compressed poly( l -lactide) monolayer are consistent with the polylactide helices lying in the plane of the air−water interface. No absorbances are observed in the PM-IRRAS spectra of poly( l -lactide) prior to the plateau in the π− A isotherms, suggesting that the helix formation is linked to the increase in surface density which accompanies film compression. The PM-IRRAS spectra establish that the conformation of the poly( l -lactide) helices with respect to the air−water interface is different than the conformation of the d / l blend helices.
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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 | 0.001 |
| 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".