Polystyrene-block-poly(acrylic acid) brushes grafted from silica surfaces: pH- and salt-dependent switching studies
Bibliographic record
Abstract
We report the preparation, characterization and responsive behavior of polystyrene-block-poly(acrylic acid) (PS-b-PAA) copolymer brushes grafted from silica substrates using Surface-Initiated Atom Transfer Radical Polymerization (SI-ATRP). pH-dependent swelling behavior was investigated in situ by ellipsometry and it confirmed that PAA chains can be reversibly switched from collapsed to extended conformations. It also confirmed that the grafted copolymer brushes were stable under extreme alkaline conditions of pH and with added salt. We showed that the hydrophobic polystyrene block of the copolymer protects the substrate–initiator bond against hydrolysis that would otherwise cause undesired polymer degrafting from the substrate. Also, we provide evidence of fundamentally different brush conformations with metal cations of increasing valency. Monovalent sodium and cesium ions caused brush stretching while only collapsed brushes were observed with divalent calcium ions.
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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) | 0.001 | 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".