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Heterogeneous “linkers” are incorporated into polymers for a number of reasons, most commonly to facilitate the coupling of the targeted backbone segments. Due to their inclusion in the backbone, these linkers have the potential to affect the overall properties of the copolymer, even when present in relatively low weight percentages. To characterize the degree of impact of some common linkers, a set of polymers that incorporate both degradable sequenced segments and linkers were synthesized and systematically examined. Seven sequence-controlled olefin containing ester macrocycles were prepared, each with a unique central moiety, including a five-carbon alkyl chain, diethylene glycol, a urea, a thioether, a triazole, a bioaromatic, and an extension of the ester sequence. The macrocycles were polymerized via ED-ROMP to yield seven polymers that vary only in the the linker segment. The properties of all polymers were compared to determine the relative dominance of the different linker types. The properties tested in the study included thermal behavior, mechanical characteristics, hydrolytic degradation and film qualities. The thermal and mechanical properties proved to be dependent primarily on the ability of the linker to promote interchain interactions, as well as the weight fraction of the linker, whereas the hydrolytic degradation was dominated by the relative hydrophobicity of the linker groups. In all cases, the linker identity was a significant contributer to the behavior.
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This content will become publicly available on July 14, 2026
Electromechanical switching in DNA–CNT supramolecular structures
The characteristics of the interface between DNA and metallic carbon nanotube (CNT) in supramolecular assemblies are important to understand for electronic and sensing applications. We study the mechanical stability and electronic properties of these interfaces with amino and ester linkers using computational experiments. Our study demonstrates that both linkers significantly enhance the mechanical stability of DNA–CNT systems, with the DNA adopting a stable and lower energy perpendicular orientation relative to the CNT as opposed to a conventional parallel arrangement. This lower energy configuration is driven by nonbonded interactions between the DNA base and the CNT surface. Our calculations also reveal that interface resistance is primarily governed by DNA–CNT interactions with negligible contribution from the linkers. In the case of the amino linker, we predict a 100-fold transmission ratio between parallel and perpendicular configurations of DNA relative to CNT. This observation can be used to build an electromechanical switch with fast switching times (30 ns). The ester linker, on the contrary, enables a better electronic coupling between the DNA and CNT even when strained.
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- PAR ID:
- 10627384
- Publisher / Repository:
- AIP
- Date Published:
- Journal Name:
- Applied Physics Letters
- Volume:
- 127
- Issue:
- 2
- ISSN:
- 0003-6951
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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