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 OBPVn-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. OBPV4-b-PNIPAM49 formed short fiber-like micelles in methanol, but aggregated into ill-defined structures in ethanol and in isopropanol. In contrast, both OBPV5-b-PNIPAM49 and OBPV6-b-PNIPAM49 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 OBPV4-b-PNIPAM49 in methanol. Although uniform fiber-like micelles of controlled lengths can be generated via self-seeding of OBPV5-b-PNIPAM49 and OBPV6-b-PNIPAM49 in methanol, only short fiber-like micelles with a length of about 94 nm were obtained for OBPV6-b-PNIPAM49. Self-seeding of OBPV5-b-PNIPAM49 and OBPV6-b-PNIPAM49 in ethanol gave uniform micelles of controlled lengths. It is interesting to note that the resistance of seed fragments of OBPV6-b-PNIPAM49 toward dissolution is much stronger than that of OPV5-b-PNIPAM49 in these solvents, even though OBPV6 has only one more phenylene vinylene unit than OBPV5. 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 OBPV5 and OBPV6 can be prepared by self-seeding of a mixture of OBPV5-b-PNIPAM49 and OBPV6-b-PNIPAM49, 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 distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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 teacher head, 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".