Reversible Cross-Linking of Polyisoprene Coronas in Micelles, Block Comicelles, and Hierarchical Micelle Architectures Using Pt(0)–Olefin Coordination
Bibliographic record
Abstract
Previous work has established that polyisoprene (PI) coronas in cylindrical block copolymer micelles with a poly(ferrocenyldimethylsilane) (PFS) core can be irreversibly cross-linked by hydrosilylation using (HSiMe(2))(2)O in the presence of Karstedt's catalyst. We now show that treatment of cylindrical PI-b-PFS micelles with Karstedt's catalyst alone, in the absence of any silanes, leads to PI coronal cross-linking through Pt(0)-olefin coordination. The cross-linking can be reversed through the addition of 2-bis(diphenylphosphino)ethane (dppe), a strong bidentate ligand, which removes the platinum from the PI to form Pt(dppe)(2). The Pt(0) cross-linking of PI was studied with self-assembled cylindrical PI-b-PFS block copolymer micelles, where the cross-linking was found to dramatically increase the stability of the micellar structures. The Pt(0)-alkene coordination-induced cross-linking can be used to provide transmission electron microscopy contrast between PI and poly(dimethylsiloxane) (PDMS) corona domains in block comicelles as the process selectively increases the electron density of the PI regions. Moreover, following the assembly of a hierarchical scarf-shaped comicelle consisting of a PFS-b-PDMS platelet template with PI-b-PFS tassels, Pt(0)-induced cross-linking of the PI coronal regions allowed for the selective removal of the PFS-b-PDMS center, leaving behind an unprecedented hollowed-out scarf structure. The addition of Karstedt's catalyst to PI or polybutadiene homopolymer toluene/xylene solutions resulted in the formation of polymer gels which underwent de-gelation upon the addition of dppe.
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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".