Langmuir Monolayers of Minimal-linker Dimeric Surfactants
Bibliographic record
Abstract
Surfactants are ubiquitous, useful compounds of immense practical significance in key industries ranging from drug-delivery to agrochemicals. The performance of these commercially valuable products depends largely on their chemical structure. The objective of the research presented in this thesis is to develop fundamental knowledge about the relationship that exists between the molecular structure of surfactants and the resulting properties of monolayer films formed from these surfactants. An ultimate goal of the project is to predict monolayer properties, including crystallographic and micron-scale structure, phase composition, miscibility and mechanical rigidity from the molecular structure of the surfactant(s) that comprise the monolayer. To achieve these goals, a minimal test system of anionic gemini surfactants referred to in this thesis as Cn-0-Cn compounds have been explored herein. The Cn-0-Cn molecules, which can be prepared with different tail-chain lengths using a tractable synthetic approach, have the shortest possible linker joining the two head-groups. Thus, these compounds are referred to as "minimal linker" compounds. The combination of a compact head-group and custom tail-chain length leads to a family of compounds that are unique amongst gemini surfactants. The shortest tail-chain homolog studied forms non-diffracting, amorphous films at the air-water (A/W) interface like other family of gemini surfacants with a bulkier head-group, whereas, the longer homologs (with n = 14, 18; Figure 0-1) present rare examples of a diffracting monolayer similar to simple fatty acids. The C14-0-C14 homolog also shows monolayer properties similar to a common phospholipid, with a defined phase transition in the classic surface pressure-area isotherms. Further, intermolecular dispersion forces play a major role in the interpretation of the observed effects in pure and binary films of Cn-0-Cn with a representative fluorosurfactant. Overall, the research presented in this thesis will be used to develop a simple, general structure-property relationship model for similar systems in future and expected to broaden the understanding of controlled variations in surfactant structures in order to obtain desirable monolayer properties.
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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 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.006 | 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".