Conformation of Arborescent Polymers in Solution by Small-Angle Neutron Scattering: Segment Density and Core−Shell Morphology
Bibliographic record
Abstract
High Resolution Image Download MS PowerPoint Slide The radius of gyration ( R g ) was determined as a function of generation number for arborescent polystyrenes with two different side chain mass average molecular mass ( M w ≈ 5000, 5K, versus 30 000, 30K) by small-angle neutron scattering (SANS) measurements. The R g values obtained were analyzed in terms of the Zimm−Stockmayer model for randomly branched polymers, the scaling relation R g ∝ M w v, and the expansion factor α s = ( R g ) goodsolvent /( R g ) ϑ solvent . The R g and scaling exponent v = 0.26 ± 0.01 found for G0 through G3 polymers with 5K side chains in cyclohexane- d correspond to the values predicted by the Zimm−Stockmayer model. The R g for G0 through G3 polymers with 30K side chains deviate from the model with v = 0.32 ± 0.02, corresponding to v = 0.33 expected for hard spheres. Deuterated polystyrene (PS- d ) side chains were grafted onto G2 and G3 polystyrene (PS) cores. These copolymers, G2PS- graft -PS- d and G3PS- graft -PS- d, were characterized as spheres with a well-defined PS core−PS- d shell structure by the SANS contrast matching method. The shape and the segment radial density profile of the core and shell for GPS- graft -PS- d were determined based on P(r ) and Δρ( r ) obtained by indirect Fourier transformation and deconvolution methods ( P(r ), pair distance distribution function and Δρ( r ) = ρ( r ) − ρ(solvent), scattering length density contrast profile).
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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".