Laser-Light-Scattering Study of Internal Motions of Polymer Chains Grafted on Spherical Latex Particles
Bibliographic record
Abstract
Using atom-transfer radical polymerization, we have prepared core−shell particles by grafting thermally sensitive poly( N -isopropylacrylamide) (PNIPAM) chains on a spherical polystyrene latex core (with a radius of ∼287 nm) via the “grafting-from” approach. As the temperature increases from 25 °C to 35 °C, the PNIPAM shell shrinks from a thickness of 625 nm to 110 nm and the chain density near the core increases from 7.3 × 10 -3 g/cm 3 to 7.2 × 10 -2 g/cm 3 . Using such core−shell particles, we have, for the first time, been able to study dynamics of long chains anchored on a particle in dilute dispersion by laser-light scattering. Our results showed that, besides the translational diffusion of the particle as a whole, there also exists an additional slow relaxation mode that is only observable at larger scattering vectors ( q ),which are presumably related to internal motions of the shell. In the fully swollen state, the relaxation rate of the slow motion (〈Γ〉 slow ) is insensitive to the observation length (1/ q ); however, its contribution to the scattering intensity ( A slow ) increases as q increases. In the shrunken state, 〈Γ〉 slow slightly decreases as q increases. 〈Γ〉 slow can be scaled to the shell thickness (〈 L 〉 brush ) as 〈Γ〉 slow ∝, with α = −2.5 ± 0.2, which is smaller than the predicated value of 3.
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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".