CAREER: Rational Synthesis and Studies of Functionalized Carbon Nanotubes

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CAREER Rational Synthesis and Studies of
Functionalized Carbon NanotubesStanislaus S.
Wong, SUNY at Stony Brook, DMR-0348239
Developing near-edge X-ray absorption fine
structure spectroscopy (NEXAFS) is critical to
characterizing nanoscale systems. (a). NEXAFS
can simultaneously track both the nature of
carbon nanotube electronic structure and the
chemical functional groups introduced.
Specifically, alterations in the p and s
transitions, indicative of extensive sidewall
functionalization, can gauge the level of
oxidation and of structural modification made to
these nanotubes. (b). Solution-phase ozonolysis
of multiwalled nanotubes (MWNTs) leads to their
opening of end caps and functionalization of
dangling bonds with oxygenated functional groups
as well as to their purification.
a
b
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CAREER Rational Synthesis and Studies of
Functionalized Carbon NanotubesStanislaus S.
Wong, SUNY at Stony Brook, DMR-0348239
We have developed an ozonolysis protocol that
purifies carbon nanotubes by removing amorphous
carbon and metal impurities. In addition,
ozonolysis provides a new means for generalizing
traditional chemistry to nanotube sidewalls,
defect sites, and surfaces. We have recently
begun developing a synchrotron-based technique
(NEXAFS) as a means of characterizing nanoscale
samples, such as carbon nanotubes and boron
nitride nanotubes. (a). NEXAFS spectroscopy is
a technique that involves the excitation of
electrons from a core level to partially filled
and empty states. It is an important
element-specific characterization tool capable of
obtaining electronic, structural, and bonding
information, not only about nanotube carbons but
also about those associated with surface
functionalities, that are introduced by oxidative
processes. We have found that NEXAFS spectroscopy
can simultaneously track both the nature of the
nanotube electronic structure and the chemical
functional groups introduced. Specifically, the
appearance of p and s transitions,
corresponding to CO and C-O oxygenated groups
respectively, as well as the attenuation of the
ring p transition, indicative of extensive
sidewall functionalization, can be used to gauge
the level of oxidation and of structural
modification made to these nanotubes. Ref.
Sarbajit Banerjee, Tirandai Hemraj-Benny,
Mahalingam Balasubramanian, Daniel A. Fischer,
James A. Misewich, and Stanislaus S. Wong, Chem.
Commun., (7), 772-773 (2004). (b). We have
presented a systematic study of the chemical and
electronic structure as well as the purity of
ozonized multiwallec carbon nanotubes (MWNTs).
These tubes have been structurally characterized
by transmission electron microscopy (TEM). This
study demonstrates the use of Raman, infrared,
and NEXAFS spectroscopies to comprehensively
determine the presence and distribution of
oxygenated moieties on these ozonized
nanotubes. Ref. Sarbajit Banerjee, Tirandai
Hemraj-Benny, Mahalingam Balasubramanian, Daniel
A. Fischer, James A. Misewich, and Stanislaus S.
Wong, ChemPhysChem, 5, 1416-1422 (2004)
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CAREER Rational Synthesis and Studies of
Functionalized Carbon NanotubesStanislaus S.
Wong, SUNY at Stony Brook, DMR-0348239
Outreach - Hosted Stephen Mui (below, right) on
a DOE Summer Undergraduate Laboratory Internship
(SULI). In his project, he used NSF-funded
facilities. - Primary organizer of Brookhaven
National Lab Open House for incoming 1st year
Chemistry departmental graduate students. Tours
of the Chemistry and Materials Sciences
Departments as well as the National Synchrotron
Light Source.
Education - Two undergraduates (V. Masson and J.
Dargan) and five graduate students (T.
Hemraj-Benny, Y. Mao, H. Zhou, F. Zhang, and T-J.
Park) contributed substantially to this work. S.
Banerjee (Ph.D. 04) also was a key player in all
of the projects. - Masson was a summer student,
supported by NSF. - Mao obtained a Sigma Xi
Grant-in-Aid of Research in 2004 and Travel Award
in 2005. - Park received a Sigma Xi Travel Award
and an American Chemical Society Division of
Inorganic Chemistry Travel Award in 2005.
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CAREER Rational Synthesis and Studies of
Functionalized Carbon NanotubesStanislaus S.
Wong, SUNY at Stony Brook, DMR-0348239
Two undergraduates (Vicki Masson and J. Dargan)
and six graduate students (Sarbajit Banerjee,
Tirandai Hemraj, Yuanbing Mao, Tae Jin Park,
Hongjun Zhou, and Fen Zhang) contributed to the
work presented. Banerjee was the key player in
all of the experiments. Hemraj-Benny and Park
participated in NEXAFS and NMR experiments,
respectively. Dargan performed large scale
chemical functionalization procedures, associated
with optimizing ozonolysis conditions. He was
involved in spectroscopic analyses of samples.
Mao, Zhou, Zhang, and Park also worked on an
off-shoot of these efforts towards understanding
the chemistry and physics of non-carbon
nanomaterials. One of the PIs outreach
initiatives was to generate added intellectual
exposure to BNL facilities for graduate and
undergraduate students. The PI hosted Stephen Mui
(undergraduate from Columbia University) on a
Department of Energy Summer Undergraduate
Laboratory Internship to perform research using
various instrumentation and facilities at
Brookhaven National Laboratory. The PI also
organized a tour for first-year Chemistry
graduate students in which they visited a range
of facilities, including the NSLS beam lines, the
Positron Emission Tomography Facility, a host of
spectroscopy and magnetic resonance imaging labs
in the Chemistry Department, and an AFM lab in
the Materials Science Department, many of which
they ended up utilizing during their subsequent
research.