Thermotropism in Tail-End (Dimethylamino)pyridinium Polymethacrylates with Bromine and Octylsulfonate Counterions
Bibliographic record
Abstract
Polyamphiphiles of the type poly(ω-dimethylaminopyridinium bromide alkyl methacrylate)s with octyl, dodecyl, and hexadecyl spacers were synthesized and further self-assembled with octylsulfonate to form stoichiometric complexes. The thermal and structural properties of both the bromine- and octylsulfonate-neutralized series (PnDMAP-Br and PnDMAP-S8, n = 8, 12, 16) were investigated in the bulk. For n = 8 in both series and n = 12 in the Br series, the materials are essentially amorphous with weak mesomorphic order. For n = 12 in the S8 series and n = 16 in both series, crystalline and disordered lamellar (smectic A) structural order is observed. Recrystallization is slow after melting, especially for P16DMAP-S8, which can be maintained indefinitely in its liquid crystal state even well above room temperature. This is attributed to the ionic interactions coupled with the polymeric character of the materials as well as, possibly, surfactant chain and polyamphiphile spacer interactions in the complexes. The liquid crystal−isotropic transition (observed clearly by DSC for n = 16 in both series, but not for P12DMAP-S8) is also affected. Plasticization by the spacer and surfactant tail reduces the well-defined glass transitions ( T g 's) of the materials, but this is mitigated by the presence of the ionic groups (the lowest T g measured, for P16DMAP-S8, is near room temperature). The lamellar period depends on the spacer length but hardly on the counterion. The properties of the two series are compared with those of other tail-end polyamphiphiles and complexes to offer an overall perspective on the bulk behavior of this class of materials, some of which are ideal candidates for forming anisotropic glasses.
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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".