An investigation of Poly(imidazolium) end groups under caustic conditions
Bibliographic record
Abstract
Fluorine-free anion exchange polymers are critical components of alkaline energy storage and conversion devices. Numerous studies have been conducted to investigate and improve the alkaline durability of these polymers. Poly(imidazolium)-based polymers, with steric protection around the electrophilic C2 position, have emerged as an alternative to fluorinated polymers due to the high ionic conductivity and high durability with respect to hydroxide attack. However, whilst many studies have focused on improving the durability of the main chain cationic repeat unit, the stability of carbonyl end groups and its effect on poly(imidazolium) backbone stability has not been explored. In this work, we investigate the stability of the diketone and aldehyde end groups of a purposely designed low molecular weight oligo(imidazolium) (DMP-PPI-AD). By comparing the behaviour of trimethylbenzaldehyde and benzil small molecules - identical to the poly(imidazolium) end groups - we were able to observe chemical rearrangements of the end groups occurring under high pH conditions. Building from this, oligo(imidazolium)s were synthesised with capped carbonyl end groups to yield imidazolium end groups, which showed no observable rearrangement or degradation under caustic conditions. Despite evidence of oligo(imidazolium)carbonyl end group rearrangement under caustic conditions, such reactions had no observable impact on the chemical structure of the imiadazolium main chain under similar high pH conditions. We conclude that degradation of end groups has no impact on the stability of poly- and oligo-(imidazoliums) under caustic conditions. • Investigation of hydroxide conducting poly(imidazolium) carbonyl end group stability. • Rearrangement of carbonyl end groups in caustic conditions do not affect do not affect poly(imidazolium) backbone. • Capping of carbonyl end groups prevents rearrangements. • Precise end-group control provides platform for optimization of alkaline-stable poly(imidazolium) properties.
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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 | 0.000 |
| 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) | 0.001 | 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".