Interface Thickness of a Styrene−Methyl Methacrylate Block Copolymer in the Lamella Phase by Direct Nonradiative Energy Transfer
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Bibliographic record
Abstract
This paper examines the use of direct nonradiative energy transfer (DET) experiments to determine the interface thickness in films of symmetric poly(styrene- b -methyl methacrylate) (PS−PMMA) block copolymers. The films were prepared from mixtures of two polymers of identical length and compositions, labeled at their junctions with either a 9-phenanthryl or 2-anthryl group. The fluorescence decays were analyzed in terms of a model that takes account of the Helfand−Tagami distribution profile of polymer segments at the interface. Reliable data analysis required careful subtraction of a background fluorescence from the measured decay profiles. Unlike neutron reflectivity experiments, DET measurements are insensitive to capillary waves at the interface. This advantage is offset by a strong sensitivity to the characteristic distance for energy transfer R 0, which has to be determined separately. When we take R 0 = 2.3 nm, we recover an interface thickness of 4.8 nm. We obtain a theoretical value of 4.2 nm when using the Semenov's finite-chain correction to Helfand−Tagami prediction and the Flory−Huggins χ FH parameter recovered by Russell for partially deuterated d-PS−PMMA copolymer. When we employ the Callaghan and Paul χ FH value for undeuterated PS + PMMA blends, we obtain δ = 4.9 nm.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
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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