Synthesis and Characterization of a Series of Azobenzene-Containing Side-Chain Liquid Crystalline Polymers
Bibliographic record
Abstract
A series of poly{4‘-{( X -methacryloyloxyalkylene)methylamino}-4-nitroazobenzene} (p X MAN, where X is the number of methylene units and varies from 2 to 12) polymers with liquid crystalline (LC) properties was synthesized. When annealed above their T g values, the whole series of polymers exhibits a stable smectic A mesophase while only the material with the shorter spacer, p2MAN, presents a smectic phase followed by a nematic phase. The spacing of the smectic layers was determined by X-ray diffraction, revealing intermolecular reorganization by interdigitation of the side-chain mesogens since the smectic layer spacing was larger than a fully extended side chain but less than two extended chains. This behavior is confirmed by temperature dependent aggregation as observed by UV−visible spectroscopy during the transition from an amorphous state to a liquid crystalline phase. The stability of the mesophase is enhanced by intermolecular interactions as argued by enthalpic and thermochromic considerations. Systematic photoinduced birefringence measurements on the various states reveal that the maximum and remnant levels of birefringence decrease with increasing the spacer length and with decreasing the glass transition temperature of the considered liquid crystalline polymer.
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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".