Rigid versus Flexible Ligands on Carbon Nanotubes for the Enhanced Sensitivity of Cobalt Ions
Carbon nanotubes have shown great promise in the fabrication of ultra-compact and highly sensitive chemical and biological sensors. Additional chemical functionalization schemes can controllably improve selectivity of the carbon nanotube-based sensors; however the exact transduction mechanism is still under debate. In this article we detail the synthesis and selective response of single-walled carbon nanotubes (SWNTs) functionalized with polyazomethine (PAM) polymer towards the application of a specific trace metal ion detector. The response of the polymer system was compared to shape persistent macrocycle (MAC) comprised of identical ion coordination ligands. While ion detection with rigid MAC/SWNT chemiresistor was comparable to bare SWNT, flexible PAM offers significant SWNT signal amplification, allowing for picomolar detection of Co{sup 2+} ions with both selectivity and a fast response. We hypothesized that rearrangement of the flexible PAM on the SWNT network is a sensing mechanism which allows for ultrasensitive detection of metal ions. The electron transfer and polymer rearrangement on the SWNT was studied by a combination of optical spectroscopy and electrical measurements - ultimately allowing for a better understanding of fundamental mechanisms that prompt device response.
- Research Organization:
- National Energy Technology Lab. (NETL), Pittsburgh, PA, and Morgantown, WV (United States). In-house Research
- Sponsoring Organization:
- USDOE Office of Fossil Energy (FE)
- DOE Contract Number:
- DE-FE0004000
- OSTI ID:
- 1129478
- Report Number(s):
- A-UNIV-PUB-017
- Journal Information:
- Macromolecules, Vol. 46, Issue 4; ISSN 0024-9297
- Publisher:
- American Chemical Society
- Country of Publication:
- United States
- Language:
- English
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