Self-Association of the Thermosensitive Block Copolymer Poly(2-isopropyl-2-oxazoline)-<i>b</i>-poly(<i>N</i>-isopropylacrylamide) in Water–Methanol Mixtures
Bibliographic record
Abstract
The dehydration and self-association of a novel thermosensitive diblock copolymer consisting of poly(2-isopropyl-2-oxazoline) and poly( N -isopropylacrylamide) (PIPOZ- b -PNIPAM) upon heating were studied in water and water–methanol (MeOH) mixtures by differential scanning calorimetry (DSC), turbidimetry, small-angle X-ray scattering (SAXS), and fluorescence depolarization. Although the difference of the phase-separation temperatures of the PIPOZ and PNIPAM homopolymers solutions was enhanced as the MeOH content in the mixed solvent increases, the DSC thermograms of PIPOZ- b -PNIPAM in water–MeOH mixtures were not bimodal, which indicates that the dehydration of each block does not occur independently. As a result, the amphiphilicity of this copolymer is weaker in the amphiphilic condition than that of the related thermosensitive block copolymer of PIPOZ and poly(2-ethyl-2-oxazoline) (PIPOZ- b -PEOZ) examined previously, which undergoes phase separation in hot water under the same conditions. Both PIPOZ- b -PNIPAM and PIPOZ- b -PEOZ solutions undergo a temperature-induced liquid–liquid phase separation, but the formation of the spherical micelle in the coexisting dilute phase is more difficult in the former solution. The colloidal stability of the coexisting concentrated phase depends on the mixed solvent composition. The colloids flocculate in conditions for which the copolymer is of intermediate amphiphilicity, as observed previously also in the PIPOZ- b -PEOZ solution, possibly due to the viscoelastic effect experienced by colloidal particles bearing on their interface chains of a more hydrophilic block.
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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) | 0.000 | 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 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".