Thermodynamic and Aggregation Properties of Gemini Surfactants with Ethoxylated Spacers in Aqueous Solution
Bibliographic record
Abstract
Critical micelle concentration (cmc), degree of micelle ionization (α), headgroup area ( a 0 ), enthalpy of micellization (Δ H ° M ), and volume of micellization (Δ V φ,M ) properties are reported for a series of (oligooxa)alkanediyl-α,ω-bis(dimethyldodecylammonium bromide) gemini surfactants, 12−EO x −12 ( x = 0−3), having several ethylene oxide moieties within the spacer group. The cmc and headgroup areas are observed to increase with an increase in the number of EO groups in the spacer, in contrast to the complex behavior of gemini surfactants ( m − s − m ) having a normal hydrocarbon chain. Also, the Δ H ° M increases (becomes less exothermic) and Δ V M decreases with an increase in the number of EO groups in the spacer. These observations are rationalized in terms of changes in the hydration and conformation of the spacer group at the micelle−bulk solution interface. Gibbs energies of micellization, Δ G ° M, and entropies of micellization, Δ S ° M, are calculated from the Δ H ° M, cmc, and α values. The results indicate that the micellization process for these surfactants is entropy-driven.
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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) | 0.000 | 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 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".