Hydrated Arrays of Acidic Surface Groups as Model Systems for Interfacial Structure and Mechanisms in PEMs
Bibliographic record
Abstract
We utilize ab initio quantum mechanical calculations in order to explore structural conformations and cooperative mechanisms at a minimally hydrated 2D array of flexible acidic surface groups. This system serves as a model for rationalizing interactions and correlations of protons and water with ionized side chains that are affixed to hydrophobic polymer aggregates in polymer electrolyte membranes (PEMs). The model exhibits two basic minimum energy configurations upon varying the separation of surface groups from 5 to 12 A. In the "upright" structure at small separation, surface groups are fully dissociated and oriented perpendicular to the basal plane. Together with hydronium ions (H3O+) they form a highly ordered network with long-range correlations. At larger separations we found the transition to a "tilted" structure with cluster-like conformation of surface groups. This structure retains only short-range correlations. Moreover, we investigated the strength of water binding to the minimally hydrated structures. At small separations between surface groups, an additional water molecule interacts only weakly with the minimally hydrated array (binding energy < 0.1 eV) while the energy needed to remove one water molecule exceeds 1 eV. This shows that the minimally hydrated systems are very stable. Ideally, these studies would expedite the design of cheap, highly performing PEMs for fuel cells, with a major focus on membranes that could operate stably at minimal hydration and elevated temperatures (>120 degrees C).
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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".