Effect of the Porosity of a Polymer of Intrinsic Microporosity (PIM) on Its Intrinsic Fluorescence
Bibliographic record
Abstract
The photophysical properties of a polymer of intrinsic microporosity, namely, PIM-1, were characterized by steady-state and time-resolved fluorescence for solutions of PIM-1 in dichloromethane (DCM) or for a membrane made of PIM-1 immersed in hexane to which a quencher was added. Quenching of PIM-1 by the proton-donor trifluoroacetic acid (TFA), electron-rich tributylamine (TBA), and electron-poor nitromethane (CH3NO2) was investigated and compared to those of the structural unit of PIM-1, the model compound M-1. Only TBA and TFA appeared to quench PIM-1 effectively. The sensitivity of monomer M-1 to the nature of the solvent led us to investigate how addition of a quencher would affect the fluorescence of the polymer PIM-1. Solvent effects were observed for TFA only and were carefully characterized. In particular, it was determined that these solvent effects could be neglected for TFA concentrations smaller than 1.4 mM. Quenching of PIM-1 by TBA was diffusional in nature and occurred in a similar manner for M-1 and PIM-1 in DCM, suggesting that M-1 is locally excited in PIM-1. All M-1 units were accessible and quenched effectively by TBA for PIM-1 in DCM and the PIM-1 membrane in hexane. Quenching of PIM-1 in DCM and in the membrane was more complex, showing a combination of static, diffusive, and protective quenching. The fraction of accessible M-1 units to TFA (f(a)) was determined to be equal to 0.5 for PIM-1 in DCM or in the membrane. The TBA and TFA quenching experiments led to the conclusion that the same accessibility was obtained for the fluorescent constituting units of PIM-1 dissolved in DCM or in a membrane immersed in hexane, in agreement with the known high microporosity of this polymer.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 teacher head, 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".