Transcript CHE5843 Spring 2003 - University of Oklahoma

CHE5480 Summer 2005
Nanostructures:
Introduction
TOPICS:
Theory: (Dr. Lee)
 Experiments (Dr. Newman)
 Computer: (Dr. Neeman)
 Attending Nanotechnology Meeting

What size is a nanometer?

A nanometer (nm) is 10-10 meter (1 m = 3.28 ft).
Nanotech: from1 nm to ~100 nm
Argon
CH4
0.3 nm
Albumin
6.5 nm
Ribosome 25 nm
0.4 nm
Red Blood Cell
2000x7000 nm
H2O
0.3 nm
What size is a nanometer? (2)
Argon
CH4
H2O
0.3 nm
0.4 nm
0.3 nm
~1 nm ~100 nm
Albumin
6.5 nm
Ribosome 25 nm
HIV virus 125 nm
Red Blood Cell
2000x7000 nm
Definition of Nanotechnology:

From NNI (National Nanotechnology Initiative) The Initiative
and its Implementation Plan :

The essence of nanotechnology is the ability to work at the molecular
level, atom by atom, to create large structures with fundamentally new
molecular organization. Compared to the behavior of isolated molecules
of about 1 nm (10 -9 m) or of bulk materials, behavior of structural
features in the range of about 10 -9 to 10 -7 m (1 to 100 nm - a typical
dimension of 10 nm is 1,000 times smaller than the diameter of a human
hair) exhibit important changes. Nanotechnology is concerned with
materials and systems whose structures and components exhibit novel
and significantly improved physical, chemical, and biological properties,
phenomena, and processes due to their nanoscale size.
22 National Agencies in NNI:
(11 of which have R&D budgets.)
National technology for the 21st century:
Leading to a new industrial revolution

Initiatives (NTR):
1.
Research on fundamental understanding and
discoveries.
Design of nanostructured materials.
Nanodevices: information, bio, medical.
Applications of nanomaterials and devices to
energy, health, evironment, and security.
Education of a new generation of skilled workers.
2.
3.
4.
5.
History of NNI:
(National Nanotechnology Initiative)

1998: IWGN (Interagency Working Group on
Nanotechnology)—National technology for the 21st
century: Leading to a new industrial revolution.

2001: NNI (Nantional Nanotechnology Initiative)—
Funding at ~500 million.

2001 NSET (National Science, Engineering, and
Technology)
Nanostructures: Old and New
Nanostructured Materials:








Carbon nanotubes
Aerogels
Zeolites
Dendrimers
Self-assembled
monolayers
Nanoparticles
Nanowires
NEMS, etc.
NSF Web
Applications of nanotechnology:
A new industrial revolution (on the scale
of the transistors in 1950s).
 Potentially it will pervade all sectors of
industry and technology.
 Essentially in the following areas:
Information, health, space,
environment, defense, etc.

Nature’s Nanodesigns
Mimicry of Nature—1
The Lotus Effect

Both surface chemistry and
surface topology influence
the hydrophobicity -slip. The
surface contains “waxy
bumps”.

Using the “Lotus effect” (that
lotus leaves are highly
Water beads up on papillae.
hydrophobic), one can
achieve slip flow (Tretheway
& Meinhart –UCSB, Silane.
Phys. Fluids 2002).
Water runs off.
Papillae on leaves.
Mimicry of Nature—2
(The lotus leaf surface)
(Feng 2002)
Papilla
μ
Mimicry of Nature—3
Water Strider
Gao, X. F. & Jiang, L.
Water-repellent legs of
water striders. Nature
432, 36 (2004).
μ
Nanosensors:
Nanosensors:

Using nanostructued
materials for detection
of trace amounts of
chemical and biological
agents. (Medical,
space, environmental,
homeland security).
Detection of Pathogens—
(Homeland Security):
Anthrax:
U.)
(Woolverton, Kent State
Detect Viruses
(Lieber, Harvard)
...and find a Cure!!!
Antimicrobial Nanoemulsion
(James Baker, U. Michigan)

Use of soybean oil emulsified
with surfactants. Drops ~400
– 600 nm.
 The droplet do not coalesce
with themselves . High
surface tension make them
coalesce with other lipid
droplets, killing bacteria.
 Safe for external use. Not
safe for red cells, or sperm.
The droplets fuse with cell membrane of
microorganisms resulting in cell lysis.
 Very effective in killing:
– Bacteria,
– Bacterial spores,
– Enveloped viruses, and
– Fungal spores.
 They are effective at preventing illness in
individuals, when used both before and after
exposure to the infective agent.
 They could be used:
– Topically,
– As an inhalant.

Antimicrobial Nanoemulsion

Left: treated with
nanoemulsion,
 Right: untreated.
 The growth of
bacteria colonies
has been eliminated
by treatment with
the nanoemulsion.
Example of Nanostructures:
Starburst Dendrimers
What is a dendrimer?
Branched polymers
(dendron = tree in Greek)
Functionality = 3 (Nitrogen)
Generations of Dendrimers
2nd
gen.
4th
gen.
5th
gen.
PAMAM Dendrimer
(polyamidoamine)

Alternating
(B)-AB-AB-AB-...
 Ethylenediamine (B)
 H2N-C-C-NH2


Methylacrylate (A)
C=C-CO-OCH3
PAMAM Moieties:
Diamine
Acrylat
e
NH3 or
Diamine
Size of PAMAM Dendrimers
(1 nm = 10 Angstroms)
Generation
M.W.
Angstrom (dia.)
End Gps
Equivalent Sizes with Cells:
Applications of Dendrimers
Gas and chemical sensors
 Catalysts
 Drug delivery and gene therapy
 Surface modifiers (tribology, and
information storage)
 Bio compatible materials
 Electronic devices and antennae

Dendrimers as
Drug Delivery Agents:
An Example
James R. Baker Jr.
University of Michigan
Professor, Internal Medicine and
Bioengineering
Chief, Division of Allergy
Director, Center for Biologic
Nanotechnology
Co-Director, Center for
Biomedical Engineering
Biotechnology,
Nanotechnology and
Immunology
Drug Delivery
 Research in the area of autoimmune endocrine
disease. He has helped define the basis of the
autoimmune response to thyroid auto antigens.
Gene Delivery
 Work concerning gene transfer; developing a
new vector system for gene transfer using
synthetic polymers (dendrimers).
Anti-microbial research
 Work on preventing pathogens from entering the
human body. This research project seeks to
develop a composite material that will serve as a
pathogen avoidance barrier and post-exposure
therapeutic agent to be applied in a topical
manner to the skin and mucous membranes.
Receptors and Ligands
Drug Delivery by Dendrimers
Dendrimers
(code named “smart bombs”)
 Targeting cancer cells
(ignore normal ones)
 Able to enter cells
 Little toxicity
Focus:
 High energy lasers or
sound wave to trigger the
release of the drug out of
the dendrimer.
Polyfunctional Tecto-dendrimers:
(connected PAMAM units)






Each “spore” in this “smart
bomb” has its function:
Sensing and binding the
target (cancer cells).
Emitting a signal (imaging).
Drug delivery in situ.
Dendrimer’s structure tricks
the immune system,
avoiding response.
Low toxicity
Economist, Dec. 2001
Professor Chris Gorman:
NCSU
Electron transfer dedndrimers
Example of Nanostructures:
Aerogels
TEM of SiO2 Aerogels
Different aerogels: (95% air)
Excellent heat insulator:
Heat Insulating Jacket
inlaid with aerogels
Example of Nanostructures:
Carbon Nanotubes
Types of Carbon Nanotubes:
1.Armchair.
Chiral
2. Zigzag.
3.
A Graphene Sheet
n=m  Armchair.
m=0  Zigzag.
others 
Gas absorbed in carbon nanotubes
Gas adsorption on banks of
carbon nanotubes
Example of Nanostructures:
Zeolites
Silicate-Aluminate:
Faujasite
Inclusion in zeolites
Mercury-removal on SAM in
Zeolite
Nanofluidics:
Flows in channels of nanometer dimension
Nanofluidics :Examples of MEMS & NEMS:
(Micro- & Nano-electromechanical systems)
Lieber (Harvard)
(“Laboratory-on-a chip”)
Lieber (Harvard)
MEMS
Flow behavior in nanofluidics:
Flow behavior in nanofluidics: (2)


1.
2.
3.
4.
5.
LOCOMOTION?
difficult to make fluid flow in small channels.
Driving forces:
Pressure
Surface-capillary force
Electric (electroosmotic, electrophoretic,
electrohydrodynamic, electrowetting), and
magnetic (magnetohydrodynamic)
Sound—acoustic
Centrifuge (rotation)
Making Circuitry by
Nanofluidics:
(Lieber, Harvard)
Purpose: using viscous flow in nanochannels.
to orient and assemble nanowires (to make
logical circuitries).
Note: at nanoscale, the surface effects are large
(due to large surface-to-volume ratio). Thus
viscous forces dominate in the flow.
(1) Make a mold of channels (PDMS-polydimethylsiloxane).
(2) Disperse nanowires (GaP, InP, Si) in ethanol, the carrier
solvent. (3) Flow the suspension through the nanochannels.
SEM images of aligned nanowires.
Charles Lieber (Harvard)--2
SEM:
bar = 2 μm
bar = 50 μm
Nanocircuitries :Examples of NEMS
Lieber (Harvard)
hydrophobic surfaces
OTS
Harvard
What happens to the flow when
the interface is hydrophobic? --Slip
2002 Phys.
Fluids
Velocity at wall is 10% of the center (NOT zero,
i.e. Slip). This increases the total volumetric
On what theories to use for nanoscale flows?
2. Nanostructured materials:
dendrimers
2. Nanostructured materials:
Gas adsorption in dendrimers
Dendrimer: PAMAM
2. Nanostructured materials:
Gas adsorption in dendrimers
3. Nanostructured materials:
Gas adsorption in aerogels
5. Self-Assembled Monolayers
Alkylatedthiols on Gold Foil
TOPICS: continued

High-performance computing (Dr. Neeman)
 Experimental program (Dr. Newman)
5. Acid gas treating in natural
gas processing
5. Acid gas treating in natural
gas processing
6. Electrolyte solutions: An
integral equation approach
7. Liquid crystals: Structure
and properties
7. Liquid crystals: Structure
and properties
7. Liquid crystals: Structure
and properties
8. Biofluids: Colloidal systems,
sol-gel transition
9. Biofluids: Polyelectrolytes
and electrical double layers
10. Natural gas hydrate:
Formation and inhibition
11. Polymer solutions: Free
energy models and statistical
mechanics