Bibliographic record
Abstract
The advent of single-molecule manipulations has renewed our interest in understanding chain molecules in confined spaces. The conformation and dynamics of these molecules depend on the degree of confinement and self-avoidance. A distinguishing feature of weakly self-avoiding polymers (e.g., DNA) in a cylindrical space is the emergence of the so-called extended de Gennes regime. On the other hand, an earlier study indicates that slit confinement enhances the self-avoidance of a Θ-polymer, for which the two-body (monomer–monomer) interaction vanishes. Using molecular dynamics simulations, we study how cylindrical confinement modulates the self-avoidance of near-Θ polymers. Our results suggest that the confinement enhances self-avoidance, turning a near-Θ solvent into a good solvent. This finding has a number of nontrivial consequences. First, it induces the linear ordering of a near-Θ chain, as if the chain is in a good solvent. Second, under strong confinement, the chain size, R∥, scales with the cylinder diameter, D, approximately as R∥ ≈ Na(D/a – 1)−4/3, where N is the number of monomers and a the monomer size. This is distinct from R∥ ≈ Na(D/a)−1 as suggested by the conventional picture, in which the second virial coefficient, B2, remains unchanged upon confinement. In contrast, enhanced self-avoidance is not easily felt by the confinement free energy unless B2 is large enough, outside the regime of a near-Θ solvent. Finally, we show how these findings are related to long-range bond–bond correlations observed for single polymers or polymer melts.
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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) | 0.001 | 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 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".