The self-assembly of gold nanorods (AuNRs) of different sizes with a block copolymer (BCP) is studied. Polystyrene- block -poly(2-vinylpyridine) (PS- b -P2VP) films containing P2VP functionalized AuNRs are solvent annealed resulting in a BCP morphology of vertical P2VP cylinders in a PS matrix. At the surface of the PS- b -P2VP films long AuNRs are found in the bridging and vertical states. The bridging state is where the long axis of the AuNR is parallel to the film surface, the AuNR is embedded in the film, and each end of the AuNR is at the top of nearest neighbor P2VP cylinders. The vertical state is where the AuNR is localized within a vertical P2VP cylinder, the AuNR long axis is perpendicular to the film surface and the upper tip of the AuNR is at the film surface. Short AuNRs were found in the bridging and vertical states as well as in a state not observed for the long AuNRs, the centered state. The centered state is where an AuNR has its long axis parallel to the film surface, is embedded in the film, and is centered over a vertical P2VP cylinder. Hybrid particle-field theory (HPFT) simulations modeling the experimental system predict that for the long AuNRs only the bridging state should be observed while for the short AuNRs only the bridging and centered states should be observed. Possible explanations for why the vertical state is observed in experiments despite being thermodynamically unfavorable in simulations are discussed. HPFT simulations also show that when a nanorod is in the bridging state the two cylinders it bridges remain intact and extend from the nanorod to the substrate. Further, the minority block of the BCP is shown to wet the bottom of the bridging nanorod. The bridging state is very promising for the future development of self-assembled nanoscale devices.
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This content will become publicly available on July 1, 2025
Response of marginal and intrinsic water-use efficiency to changing aridity using FLUXNET observations
Status: The paper is pending acceptance with minor revision. The revisions were returned to the publisher for review in May 2024. A preprint of the submitted version is available at: https://escholarship.org/uc/item/54m1b3t8
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- Award ID(s):
- 2012893
- NSF-PAR ID:
- 10520710
- Publisher / Repository:
- preprint at escholarship.org
- Date Published:
- Journal Name:
- Journal of geophysical research Biogeosciences
- ISSN:
- 2169-8953
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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