Collective Short-Time Dynamics in Polymer Melts: Two-Step Quenches and Spinodal Decomposition
Bibliographic record
Abstract
High Resolution Image Download MS PowerPoint Slide In polymer melts, the segmental density does not simply relax diffusively due to intramolecular dynamics on short time scales. Using particle-based simulations of a highly coarse-grained polymer model, we explore the collective short-time dynamics under two distinct scenarios: (i) noninteracting polymer chains subject to a two-step change of an external field and (ii) phase separation due to attractive interactions. In the case of the two-step external field, we observe a nonmonotonic relaxation behavior of a collective density modulation, while for the case of the spontaneous growth of density modulations in response to the introduction of attractive interactions (spinodal decomposition), we observe an initial nonexponential growth on very short time scales, followed by a transition to exponential growth. We show that these effects can be captured by linear response theory, in contrast to dynamic self-consistent field theory (D-SCFT) that always predicts a slow exponential relaxation of segmental density modes. The short-time deviations from D-SCFT stem from two key characteristics: (i) the molecular configurations are not in equilibrium with the instantaneous density field, and (ii) the segmental dynamics display subdiffusive behavior.
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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".