Comparative Thermodynamic Studies of the Micellization of Amphiphilic Block Copolymers before and after Cyclization
Bibliographic record
Abstract
The enthalpy and entropy of micellization in water, Δ H mic and Δ S mic, respectively, of three linear amphiphilic BAB block copolymers consisting of either poly(methyl acrylate) ( M n ∼ 1200 and 700 Da) or poly(ethyl acrylate) ( M n ∼ 800 Da) as hydrophobic (B) segments and poly(ethylene oxide) (PEO) as the hydrophilic (A, M n ∼ 3000 Da) segment were determined by isothermal titration calorimetry (ITC). The Δ H mic and Δ S mic of the cyclic AB block copolymers obtained by cyclization of the linear triblock copolymers were determined under the same conditions. The Δ H mic value of the cyclic copolymers was smaller than that of their linear precursors. The Δ S mic value showed the same trend, but the relative difference between the cyclized and linear copolymers was less pronounced. The hydrodynamic diameter ( D h ), critical micelle concentration (CMC), molecular weight ( M w-mic ), and second virial coefficient ( A 2 ) of the micelles were determined. The D h value of the cyclic copolymer micelles was smaller than the linear counterpart. On the other hand, the CMC value became larger, whereas the A 2 value was comparable or increased by cyclization. Overall, the results suggest that, in the unimer state, the hydrophobic segments of the cyclized copolymers form a tightly coiled structure to minimize contact with water, resulting in the smaller Δ H mic value. Contrary to the linear copolymer micelles, the cyclic copolymer micelles have no “dangling chains”, which may explain the topology-driven slight difference in the Δ S mic value.
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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 | 0.001 |
| 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) | 0.002 | 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".