CHE5480%20Summer%202005

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CHE5480 Summer 2005

• Nanostructures Introduction

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TOPICS

• Theory (Dr. Lee)
• Experiments (Dr. Newman)
• Computer (Dr. Neeman)
• Attending Nanotechnology Meeting

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What size is a nanometer?

• A nanometer (nm) is 10-10 meter (1 m 3.28 ft).

Nanotech from1 nm to 100 nm Albumin 6.5
nm Ribosome 25 nm
Argon 0.3 nm CH4 0.4 nm H2O 0.3 nm
Red Blood Cell 2000x7000 nm
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What size is a nanometer? (2)
HIV virus 125 nm Red Blood Cell 2000x7000 nm
Argon 0.3 nm CH4 0.4 nm H2O 0.3 nm
1 nm 100 nm Albumin 6.5 nm Ribosome 25 nm
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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.

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22 National Agencies in NNI(11 of which have
RD budgets.)
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National technology for the 21st century Leading
to a new industrial revolution

• Initiatives (NTR)
• 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.

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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)

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Nanostructures Old and New
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Nanostructured Materials

• Carbon nanotubes
• Aerogels
• Zeolites
• Dendrimers
• Self-assembled monolayers
• Nanoparticles
• Nanowires
• NEMS, etc.

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NSF Web
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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.

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Natures Nanodesigns
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Mimicry of Nature1 The Lotus
Effect
Water runs off.

• Both surface chemistry and surface topology
  influence the hydrophobicity -slip. The surface
  contains waxy bumps.
• Using the Lotus effect (that lotus leaves are
  highly hydrophobic), one can achieve slip flow
  (Tretheway Meinhart UCSB, Silane. Phys. Fluids
  2002).

Papillae on leaves.
Water beads up on papillae.
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Mimicry of Nature2(The lotus leaf surface)
(Feng 2002)
Papilla
µ
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Mimicry of Nature3Water Strider
Gao, X. F. Jiang, L. Water-repellent legs of
water striders. Nature 432, 36 (2004).
µ
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Nanosensors
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Nanosensors

• Using nanostructued materials for detection of
  trace amounts of chemical and biological agents.
  (Medical, space, environmental, homeland
  security).

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Detection of Pathogens(Homeland Security)
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Anthrax (Woolverton, Kent State U.)
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Detect Viruses(Lieber, Harvard)
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...and find a Cure!!!
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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.

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• 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.

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Antimicrobial Nanoemulsion

• Left treated with nanoemulsion,
• Right untreated.
• The growth of bacteria colonies has been
  eliminated by treatment with the nanoemulsion.

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Example of NanostructuresStarburst Dendrimers
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What is a dendrimer? Branched polymers
(dendron tree in Greek)Functionality 3
(Nitrogen)
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Generations of Dendrimers
Your Text Here
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Generations of Dendrimers
2nd gen.
5th gen.
4th gen.
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PAMAM Dendrimer (polyamidoamine)

• Alternating
• (B)-AB-AB-AB-...
• Ethylenediamine (B)
• H2N-C-C-NH2
• Methylacrylate (A)
• CC-CO-OCH3

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PAMAM Moieties
Diamine
Acrylate
NH3 or Diamine
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Size of PAMAM DendrimersGeneration
M.W. Angstrom (dia.)
End Gps
(1 nm 10 Angstroms)
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Equivalent Sizes with Cells
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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

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Dendrimers as Drug Delivery AgentsAn Example
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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

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• 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.

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Receptors and Ligands
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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.

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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.
• Dendrimers structure tricks the immune system,
  avoiding response.
• Low toxicity

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Economist, Dec. 2001
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Professor Chris GormanNCSU
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Electron transfer dedndrimers
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Example of NanostructuresAerogels
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TEM of SiO2 Aerogels
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Different aerogels (95 air)
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Excellent heat insulator
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Heat Insulating Jacket inlaid with aerogels
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Example of Nanostructures Carbon Nanotubes
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Types of Carbon Nanotubes
1.Armchair. 2. Zigzag. 3. Chiral
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A Graphene Sheet
nm ? Armchair. m0 ? Zigzag. others ?
Chiral.
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Gas absorbed in carbon nanotubes
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Gas adsorption on banks of carbon nanotubes
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Example of Nanostructures Zeolites
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Silicate-AluminateFaujasite
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Inclusion in zeolites
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Mercury-removal on SAM in Zeolite
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Nanofluidics Flows in channels of nanometer
dimension
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Nanofluidics Examples of MEMS NEMS (Micro-
Nano-electromechanical systems)
Lieber (Harvard)
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(Laboratory-on-a chip)
Lieber (Harvard)
MEMS
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Flow behavior in nanofluidics
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Flow behavior in nanofluidics (2)

• LOCOMOTION?
• difficult to make fluid flow in small
  channels.
• Driving forces
• Pressure
• Surface-capillary force
• Electric (electroosmotic, electrophoretic,
  electrohydrodynamic, electrowetting), and
  magnetic (magnetohydrodynamic)
• Soundacoustic
• Centrifuge (rotation)

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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.

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(1) Make a mold of channels (PDMS-polydimethylsilo
xane). (2) Disperse nanowires (GaP, InP, Si) in
ethanol, the carrier solvent. (3) Flow the
suspension through the nanochannels.
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SEM images of aligned nanowires.
Charles Lieber (Harvard)--2
SEM bar 2 µm
bar 50 µm
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Nanocircuitries Examples of NEMS
Lieber (Harvard)
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hydrophobic surfaces
OTS
Harvard
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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
flow.
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On what theories to use for nanoscale flows?
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2. Nanostructured materials dendrimers
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2. Nanostructured materials Gas adsorption in
dendrimers
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Dendrimer PAMAM
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2. Nanostructured materials Gas adsorption in
dendrimers
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3. Nanostructured materials Gas adsorption in
aerogels
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5. Self-Assembled Monolayers
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Alkylatedthiols on Gold Foil
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TOPICS continued

• High-performance computing (Dr. Neeman)
• Experimental program (Dr. Newman)

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5. Acid gas treating in natural gas processing
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5. Acid gas treating in natural gas processing
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6. Electrolyte solutions An integral equation
approach
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7. Liquid crystals Structure and properties
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7. Liquid crystals Structure and properties
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7. Liquid crystals Structure and properties
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8. Biofluids Colloidal systems, sol-gel
transition
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9. Biofluids Polyelectrolytes and electrical
double layers
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10. Natural gas hydrate Formation and inhibition
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11. Polymer solutions Free energy models and
statistical mechanics