Determination of Molecular Orientation in Biaxially Oriented Ultrathin Films
Bibliographic record
Abstract
Biaxial orientation in ultrathin films is characterized by a preferential orientation of the main molecular axis in the plane of the film in addition to its orientation with respect to the normal of the film. In this paper, analytical expressions allowing the calculation of the molecular orientation in biaxially oriented films from their anisotropic optical constants are presented for the first time. These expressions have been used to calculate the molecular orientation in multilayers of poly(γ-benzyl- l -glutamate) and to determine the angles between the main molecular axis and the different transition moments used (α angles). Using the optical constants determined by Buffeteau et al. 1 for PBG multilayers, we have found that the tilt angle of the PBG helices with respect to the monolayer normal is 89° and that the azimuthal angle in the plane is 57°. The calculated α angles for the carbonyl stretching mode of the ester group and the amide I and amide II modes of the amide group are 49, 34 and 74°, respectively. The analytical expressions presented in this paper have also been used to calculate the molecular orientation in Langmuir−Blodgett monolayers of an equimolar blend of poly( d -lactide) and poly( l -lactide). The optical constants of a monolayer of the polylactide mixture determined using p- and s-polarized transmittance and p-polarized reflection−absorption infrared spectra have shown that the polylactide helices have a tilt angle of 81° and an azimuthal angle of 56°.
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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 | 0.001 | 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) | 0.000 | 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 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".