Versatile Synthesis of End-Functionalized Thermosensitive Poly(2-isopropyl-2-oxazolines)
Bibliographic record
Abstract
The synthesis of several end-functionalized poly(2-isopropyl-2-oxazolines) (P i PrOx) has been achieved via cationic ring-opening polymerization of 2-isopropyl-2-oxazoline. Poly(2-isopropyl-2-oxazolines) bearing primary amino groups at one chain end (Me-P i PrOx-NH 2, with M n ranging from 3600 to 9700) were obtained by conversion of hydroxyl-terminated poly(2-isopropyl-2-oxazolines) (Me-P i PrOx-OH) via phthalimide activation of the hydroxyl groups and subsequent hydrazine treatment. Heterotelechelic P i PrOx carrying an α-acetal and an ω-hydroxyl group (acetal-P i PrOx-OH) were prepared via cationic ring-opening polymerization of 2-isopropyl-2-oxazoline initiated with 3,3-diethoxy-1-propyl tosylate. The polymerizations carried out under mild conditions (40−45 °C) for extended periods of time yielded polymers of well-controlled molecular weight (MW) and narrow molecular weight distribution (MWD). Analysis of the polymers by 1 H and 13 C NMR spectroscopy, ion-exchange HPLC, and MALDI−TOF mass measurements indicated that nearly quantitative end-functionalization was achieved in all cases. Aqueous P i PrOx solutions (10 mM PBS (pH 7.4) containing 150 mM NaCl) possess a cloud point temperature near 37 °C, as determined by turbidity. Thermosensitive telechelic P i PrOx offer promising applications as smart materials including bioconjugates, hydrogels, and drug carriers.
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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) | 0.001 | 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 | 0.001 |
| 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".