Making Hydrophilic Polymers Thermoresponsive: The Upper Critical Solution Temperature of Copolymers of Acrylamide and Acrylic Acid
Bibliographic record
Abstract
Homopolymers of acrylamide and acrylic acid are known to be hydrophilic and soluble in water. Their copolymers are soluble in water at neutral pH but can be turned into polymers possessing an upper critical solution temperature (UCST) behavior when the carboxylic acid groups are protonated (pH < 3). At temperatures below the UCST, the formation of interchain hydrogen bonds between the acid and amide groups makes the copolymers insoluble. These hydrogen bonds are disrupted when the temperature is heated above the critical temperature ( T c ), exhibiting a UCST behavior. In this study, linear water-soluble random copolymers of acrylamide and acrylic acid of different compositions and molar masses have been synthesized. The thermoresponsive properties of the copolymers were studied to elucidate the effects of their composition, molar mass, and concentration by measuring their cloud point temperatures ( T cp ) in acidic buffer solutions to keep the carboxylic acid groups in the protonated state. The effects of pH and added salts or urea were also studied.
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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 | 0.001 |
| 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".