How a Small Change of Oligo(<i>p</i>-phenylenevinylene) Chain Length Affects Self-Seeding of Oligo(<i>p</i>-phenylenevinylene)-Containing Block Copolymers
Bibliographic record
Abstract
Self-seeding of copolymers with a π-conjugated crystalline segment has been considered to be a versatile approach of living crystallization-driven self-assembly to generate uniform fiber-like nanostructures with a semiconducting core. The structure of a core-forming block, one of the most important factors affecting the self-seeding process, has not yet been systematically investigated. We synthesized three well-defined diblock copolymers of OBPV n - b -PNIPAM [OBPV = oligo(2,5-dibutyloxy-1,4-phenylenevinylene), PNIPAM = poly( N -isopropyl acrylamide), with n = 4, 5, 6, and the same corona-forming PNIPAM block. Here, the subscripts represent the number of repeat units of each block.] We then examined in detail their self-assembly behavior, especially under self-seeding conditions. OBPV 4 - b -PNIPAM 49 formed short fiber-like micelles in methanol, but aggregated into ill-defined structures in ethanol and in isopropanol. In contrast, both OBPV 5 - b -PNIPAM 49 and OBPV 6 - b -PNIPAM 49 formed fiber-like micelles of uniform width and with lengths of about 1–2 μm in these solvents. Fiber-like micelles with a broad length distribution were formed by self-seeding of OBPV 4 - b -PNIPAM 49 in methanol. Although uniform fiber-like micelles of controlled lengths can be generated via self-seeding of OBPV 5 - b -PNIPAM 49 and OBPV 6 - b -PNIPAM 49 in methanol, only short fiber-like micelles with a length of about 94 nm were obtained for OBPV 6 - b -PNIPAM 49 . Self-seeding of OBPV 5 - b -PNIPAM 49 and OBPV 6 - b -PNIPAM 49 in ethanol gave uniform micelles of controlled lengths. It is interesting to note that the resistance of seed fragments of OBPV 6 - b -PNIPAM 49 toward dissolution is much stronger than that of OPV 5 - b -PNIPAM 49 in these solvents, even though OBPV 6 has only one more phenylene vinylene unit than OBPV 5 . These results demonstrate that the OBPV chain length significantly affects the self-seeding behavior of OBPV-based copolymers. Intriguingly, uniform comicelles with a heterogeneous core of OBPV 5 and OBPV 6 can be prepared by self-seeding of a mixture of OBPV 5 - b -PNIPAM 49 and OBPV 6 - b -PNIPAM 49, indicative of the great potential of synergistic self-seeding in the fabrication of semiconducting nanofibers with a heterogeneous core.
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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".