Relationships of Acid and Water Content to Proton Transport in Statistically Sulfonated Proton Exchange Membranes: Variation of Water Content Via Control of Relative Humidity
Bibliographic record
Abstract
An in-depth analysis for proton exchange membranes to examine the effects of acid concentration and effective proton mobility upon proton conductivity as well as their relationship to water content was carried out on two main-chain, statistically sulfonated polymers at 25 degrees C. These polymer systems consisted of poly(ethylenetetrafluoroethylene-graft-polystyrenesulfonic acid) (1) and sulfonated trifluorostyrene (BAM) membrane (2). Nafion (3) was used for comparison. Water content (as represented by Xv, the water volume fraction, where Xv = volume of water in hydrated PEM / volume of hydrated PEM), for each sample was varied by adjusting the relative humidity (RH) of the membrane environment from 50% to 98%. It was found that, at low RH (RH < 70%), the major factor determining proton conductivity is proton mobility. In order to remove the differences in acid strength for the membranes, proton mobility values at infinite dilution (Xv = 1.0) and 25 degrees C were calculated and found to be 2.6 +/- 0.2 x 10-3 (average of 1a-c), 1.6 +/- 0.3 x 10-3 (average of 2a-e), and 2.32 +/- 0.01 x 10-3 cm2 s-1 V-1 (3). These were then compared to the theoretical value for the mobility of a free proton at infinite dilution and to previously reported data. Possible differences in tortuosity and the juxtaposition of acid groups are proposed in order to account for the significant deviations of all samples from the theoretical value.
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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".