Synthesis and self-assembly of gradient copolymers
Bibliographic record
Abstract
Controlled free radical polymerization allows for the fine control of many key properties of polymers such as the molecular weight, dispersity and composition.Consequently, this permits the attainment of interesting microstructures such as block or tapered/gradient copolymers.In particular, nitroxide-mediated polymerization (NMP) was applied and used for the polymerization of methyl methacrylate (MMA) and styrene (St) block and tapered gradient polymers.With the defined composition and molecular weight, such copolymers are able to self-assemble into sub-50 nm domains.In this thesis, gradient copolymers synthesized in semibatch mode were produced with varying composition and gradient profiles by alternating the rate of St addition and the length of the reaction.Their self-assembly performance was assessed relative to block copolymers with identical molecular properties and found to have similar feature sizes.However, with increasing gradient length, the self-assembly is negatively affected, producing films with very little order and much higher defect densities than block copolymers or polymers with short gradient lengths. RÉSUMÉLa polymérisation radicale contrôlée permet le contrôle précis de plusieurs propriétés clés des polymères, tels que la masse moléculaire, dispersité et composition.Par conséquent, ce qui permet la réalisation de microstructures intéressants tels que copolymères bloque ou gradient.En particulier, on a appliqué la polymérisation nitroxide-médié (NMP) pour polymériser le méthacrylate de méthyl (MMA) et le styrène (St) en copolymères bloque et gradient.Avec la composition et masse moléculaire définie, ces polymères peuvent effectuer l'auto-assemblage en domaine moins de 50 nm.Dans cette thèse, des copolymères gradient ont été synthétisé en manière semi-continu avec profils de composition et de gradient variant en alternant le taux d'addition de St et la durée de la réaction.Leur performance d'auto-assemblage a été évaluée par rapport à des copolymères bloque ayant des propriétés moléculaires identiques et ont été trouvés à avoir des tailles de domaines similaire.Cependant, avec l'augmentation de la longueur de gradient, l'auto-assemblage est négativement affecté, la production de films avec très peu d'ordre et beaucoup plus de défauts que des copolymères bloque ou des copolymères avec des longueurs de gradient plus courtes.
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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 | 0.001 |
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".