Characterization of Functional Nanomachines
Michael Crommie, Program Leader
This program encompasses the:
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Development and application of controllable, operational nanomachines
and nanomotors from molecular building blocks.
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Synthesis, characterization, and implementation/attachment
of new molecules having tailored geometry, electro-activity,
photonic response, and surface reactivity for use as nanomachine
components.
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Determination of the mechanisms of chemical-to-mechanical
energy transfer in naturally occurring molecular bio-motors
and artificial bio-motor assemblies.
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Reengineering Nature’s molecular machines to create
nanomachines with new functional properties.
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Theoretical prediction and explanation of nanomotor behavior
through ab initio electronic structure calculations.
 Two STM images are shown of the
same 90 Angstrom x 90
Angstrom
patch of a molecule-covered gold surface before and after irradiating
the surface with UV light (represented by the purple “beam” that
has been sketched in). The molecules, tetra-tert-butyl-azobenzene
(TTB-azobenzene), were chemically engineered by J. Frechet’s
group to photomechanically switch from one mechanical configuration
to another at a surface for nanomachine applications. In
the top STM image all of the molecules are in the “trans” isomer
configuration, while in the bottom STM image the two tall spikes
show two individual TTB-azobenzene molecules that have mechanically
switched to the “cis” configuration
(a completely different mechanical state) by absorbing ultraviolet
photons.
CURRENT PROJECTS
I. Optomechanical molecular switching at a surface
(M.
Crommie, J.
Frechet, S.
Louie)
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Understanding the mechanisms of molecule photoswitching on
a surface for nanomachine application
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Control of molecular photoswitching by structural means and
by plasmon control
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Controlled assembly of photomechanically active molecules
at surfaces
II. Electrical actuation of mechanically active molecules
(M.
Crommie, A.
Zettl, J.
Frechet)
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Molecular systems that are mechanically active through electrical
actuation will be studied with a custom instrument currently
under construction that combines lateral electric field
generation, STM, and high frequency detection capability.
III. Assembly of molecules into nanomechanical systems (J.
Frechet, A. Zettl, M.
Crommie)
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Mechanical control of molecules using hydrophilic patterning
on a surface
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AFM local biasing of a desiged monolayer that couples the
turning on of fluorescence with molecular-mechanical modification
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Repetitive light-driven switching in molecules that results
in their ‘crawling’ along a surface
IV. Light-control of Chemical-Mechanical Energy Conversion
in Biomotors (C.
Bustamante, A.
Zettl)
V. Nanotube Molecular Motors (A.
Zettl,
C.
Bustamante, M.
Cohen, S.
Louie)
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Fabrication and characterization of coherently operating assemblies
of nanotube-based nanomachines
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Observation of the wear on an operating multi-wall nanotube
bearing via in-situ TEM characterization
-
Attachment of a DNA strand to a MWNT to serve as a transducer
to a bead in an optical tweezer
VI. Theory and modeling studies (S.
Louie, M.
Cohen)
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