Characterization of the Aggregates Made by Short Poly(ethylene oxide) Chains Labeled at One End with Pyrene
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Bibliographic record
Abstract
The association of a monodisperse poly(ethylene oxide) 53 ethylene oxide units long and labeled at one end with pyrene (Py-PEO) was monitored as a function of Py-PEO concentration by steady-state and time-resolved fluorescence, surface tension, static (SLS), and dynamic (DLS) light scattering. The excimer fluorescence decays exhibit no rise time for any polymer concentration investigated in this study (>0.5 g/L), indicating that pyrene aggregates are present in solution and confirming the existence of Py-PEO micelles. No excimer emission could be detected for Py-PEO concentration smaller than 0.1 g/L. The first critical aggregation concentration (CAC1) for the formation of Py-PEO micelles was estimated to equal 0.003 g/L by SLS. The Py-PEO micelles are surface active above a Py-PEO concentration larger than 0.001 g/L (0.4 μM) where a clear drop in surface tension is observed at concentrations slightly lower than CAC1. At a Py-PEO concentration of 10 g/L, the surface tension plateaus due to the aggregation of Py-PEO micelles. This corresponds to a second critical aggregation concentration referred to as CAC2. The aggregation was probed by DLS. DLS provided the hydrodynamic diameter of the Py-PEO micelles, which was found to equal 7.2 ± 3.1 nm. Fluorescence was used to determine the aggregation number of the Py-PEO micelles, which was found to equal 20 ± 2. The combination of the aggregation number found by fluorescence and the hydrodynamic radius found by DLS led to the conclusion that the Py-PEO micelles are made of a hydrophobic pyrene-rich core surrounded by a corona of collapsed PEO chains.
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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) | 0.001 | 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 it