The role of molecular volume and the shape of the hole transport molecule in the morphology of model charge transport composites
Bibliographic record
Abstract
We present a study of the morphology and molecular interactions in a model charge transport composite with 1,1-bis(di-4-tolylaminophenyl) cyclohexane (TAPC) as the hole transport molecule in bisphenol-A polycarbonate (BPAPC) and cyclohexyl polycarbonate, also known as bisphenol-Z polycarbonate (PCZ). Solution NMR shows that while there is aromatic interaction between the phenyl groups of the polycarbonate and TAPC, the broadening of the peaks corresponding to the latter indicates a decrease in the rotational motion. FTIR spectroscopy also exhibits frequency shifts of the aromatic C–H absorption peaks, which parallels the extent of the depression of the glass transition temperature (Tg) of the polycarbonate. These are compared with the previous results for N,N-diphenyl-N,N-bis(3-methylphenyl)-[1,1-biphenyl]-4,4-diamine (TPD) and tri-p-tolylamine (TTA), and the differences are rationalized on the basis of the molecular shape and van der Waals volume of the small molecules. It is proposed that when the polycarbonate is in a random coil conformation, spherical small molecules (e.g., TAPC and TTA) reduce the glass transition temperature much more than a rodlike small molecule (e.g., TPD). Annealing at a temperature just below the Tg of the polycarbonate was used as a means of simulating accelerated ageing. Upon annealing, phase separation and crystallization of TAPC occurs and leads to a recovery of the Tg of the polymer significantly. The Tg recovery in this case is much more significant than in the case of TPD. The average crystal sizes are about ten times smaller than the crystals obtained in the case of TPD for the same temperature of annealing. To enhance the charge mobility, it might actually be advantageous to induce submicron crystals of the small molecule, while keeping the film transparent.
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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) | 0.000 | 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".