Molecular Dynamics Study of the Molecular Weight Dependence of Surface Tensions of Normal Alkanes and Methyl Methacrylate Oligomers
Bibliographic record
Abstract
Surface tensions (gamma) of normal alkanes and methyl methacrylate (MMA) oligomers at various molecular weights in the low molecular weight range were computed using a newly proposed molecular dynamics (MD) simulation strategy which was developed based on the definition of gamma = ( partial differential U/ partial differential sigma)n,V,S. The MD simulations, even with the use of a generic force field, reproduced the experimentally observed molecular weight dependence of gamma (i.e., gamma proportional Mn(-2/3), where Mn is the number-average molecular weight) for both series of oligomers. Analysis of the data reveals that solvent accessible surface area, one of the key input variables used for the calculation of gamma, exhibits an Mn(2/3) (rather than Mn(1)) dependence. The reason for such dependence is that solvent accessible surface area formed by the chainlike small molecules depends, to a larger extent, on their orientations rather than their size. However, this is not the case for high molecular weight molecules as solvent accessible surface area of such surfaces are determined by the orientations of their segments which are determined by the conformations of the molecules. This may explain why surface tension of polymers experimentally exhibits an Mn(-1) dependence. It is inferred that the corresponding molecular weight dependence of the entropy changes associated with molecules in the low and high molecular weight ranges would be different.
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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".