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2004
LSU-HHMI Summer Undergraduate Research Program |
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 Pavan
Bellamkonda, Paul Russo, Chemistry
Production of rodlike particles with continuously variable
length
Rodlike particles with controlled, variable length can make
liquid crystals for optical displays and physical color applications.
They can encode information and serve as microviscosity probes
of biofluids and other solutions whose rheological properties
are difficult to measure, such as polymers in environmentally
friendly supercritical fluids. Two approaches to such particles
have been pursued, one based on arborol surfactants and the
other on electrodeposition of gold in alumina channel templates.
Arborols were first synthesized by Newkome et al. The two-directional
[m]-n-[m] arborols consist of twin hydrophilic regions, each
with m terminal hydroxyl groups, connected by a linear alkyl
chain with the formula CnH2n. These molecules are of interest
due to their self-assembling ability, which leads to reversible
gels in water. The extended, fibrillar nature of the gels resembles
the structures formed by ß-amyloid, the peptide comprising
most of the plaques found in the brains of patients afflicted
with Alzheimer’s disease. In addition to the applications
mentioned above, arborol research can contribute to method developments
that may help to characterize Alzheimer’s and other amyloid
related diseases. One strategy to control arborol growth is
to introduce other amphiphiles, such as a one-directional arborol.
The results suggest that fiber length can be controlled.
Gold nanorods are produced by electrodeposition using a standard
commercially available filter of uniform pore size of 0.2 µm.
The length is governed by the duration, current and potential
of the process. First attempts to produce these nanoparticles
were successful, but it remains a challenge to disperse them
in solution. Supported by NSF DMR-0075810. This research was
supported in part by a Howard Hughes Medical Institute grant
through the Undergraduate Biological Sciences Education Program
to Louisiana State University.
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