Association Behavior of Star-Shaped pH-Responsive Block Copolymer: Four-Arm Poly(ethylene oxide)-<i>b</i>-Poly(methacrylic acid) in Aqueous Medium
Bibliographic record
Abstract
A four arm pH-responsive poly(ethylene oxide)-b-poly(methacrylic acid) block copolymer was synthesized by atom transfer radical polymerization technique. The conformation transition over the course of neutralization was investigated using a combination of potentiometric and conductometric titrations, dynamic and static light scattering, and transmission electron microscopy. The multiarm block copolymer existed as an extended unimer at high pH due to the negatively charged carboxylate groups and hydrophilic poly(ethylene oxide) segments. The block copolymers self-assembled into core-shell micelles and large spherical aggregates that flocculated at low degree of neutralization (alpha). Such behavior is controlled by the fine balance of electrostatic, hydrophobic, and hydrogen bond interactions. The hydrodynamic radius (R(h)) of the aggregates was approximately 84 nm at alpha of 0.3, and it decreased to 63 and 46 nm at alpha approximately 0.2 and 0.1, respectively, as a result of the reduced electrostatic interaction between ionized carboxylate groups. The thermodynamic parameters obtained from isothermal titration calorimetric technique in different salt concentrations indicated that the energy to extract a proton from a charged polyion was reduced by the addition of salt, which favors the neutralization process.
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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".