Lab Information
• Prepare photoresist – groups of 3 to 4 people
1 mg oil red (solvent red 27)
3.5 g isobornyl acrylate (IBA)
2.0 g 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy)phenyl]propane (bis-GMA)
0.18 g 2,2-dimethoxy-2-phenyl-acetophenone (DMPA)
• Wear gloves!
• Expose photoresist with UV lamp (goggles will absorb UV)
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Special Nanomaterials &
Carbon Nanotechnology
(Section 4.4.6)
NANO 101
Introduction to Nanotechnology
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What are “special nanomaterials”?
• Materials that are made using unique processes
• Materials that have unique structures and/or properties
• Examples:
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Special Nanomaterials: Outline
• Micro and Mesoporous Materials
• Ex. Zeolites, Metal-Organic Framework (MOF)
• Core-Shell Structures
• Carbon Nanotechnology
– Nanotubes
– Fullerenes
– Other organic molecules
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Micro and Mesoporous Materials
http://greman.univ-tours.fr/axis3/porous-silicon-for-dummies-page-1276071.kjsp
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Random Mesoporous Structures
• Variety of methods of synthesis
– Oxidation of metal foils using acids
– Radiation-track etching
– Sol-gel processing
• Sol-gel processing
• aerogel: 75-90% porosity
• xerogel: ~ 50 % porosity
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Sol Gel Processing
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http://www-cmls.llnl.gov/?url=science_and_technology-chemistry-solgel_chemistry
Crystalline Mesoporous Structures:
Zeolites
•
•
•
•
Crystalline aluminosilicates
First discovered in 1756
34 are naturally-occurring
3-D framework with uniformly-sized pores
– Pores: ~ 0.3 – 1.0 nm in diameter
– Pore volumes: ~ 0.1 – 0.35 ml/g
• Applications:
– Catalysts
– Adsorbents/molecular sieves
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Crystalline Mesoporous Structures:
Zeolites
N&N Fig. 6.13
N&N Fig. 6.12
Various arrangements
•
•
•
•
Rings
Cages
Channels
Chains
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http://omnibus.uni-freiburg.de/~weisenbt/7Zeolites/ZeoliteDefinition.html
MOFs
• Similar to zeolites,
more syntheic
flexibility
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Core-Shell Structures
•
Core and shell made of two different materials
•
Differences:
• Crystal structure (lattices, arrangements of atoms)
• Physical properties
• Example: one metallic, one insulating
• Method of synthesis
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Core-Shell Structure Example:
Metal-Polymer
• Membrane-Based Synthesis
– Metal particles trapped inside pores
– Add polymer solution into pores and react
• Use as ligand and polyimerize
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Fratoddi et al. Nanoscale Research Letters 2011, 6:98
Membrane Based Core-Shell
• Au shell, polyaniline core
Nano Lett.
Sep 2006;
6(9): 2166–
2171. 13
Other Core-Shell
Chemistry of Materials 2011, 23, 4587–4598.
• Semiconductor Passivation
• More Tunability
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Carbon Nanostructures
Variety of properties
Metallic conductor (graphite)
Semiconductor (diamond)
3-D
Insulating Polymer
(hydrocarbon chains)
Variety of structures
1-D
2-D
0-D
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Carbon Fullerenes
• 0-dimensional carbon structure
• Usually C60, but also refers to C70, C76, Cn (n > 60)
• Every carbon site on C60 is equivalent
– Bonded to three other carbons
– average bond is 1.44 Å (C-C is 1.46 Å; C=C is 1.40 Å)
• 20 hexagonal faces; 12 pentagonal faces
• Diameter: 7.10 Å
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Buckminster Fuller (1895-1983):
Architect, engineer, inventor; Developed the geodesic dome
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Synthesis of Fullerenes
• Laser ablation (vaporizing graphite with a laser)
• Plasma arcing of graphite or coal
– Fullerenes found in the soot
• Combustion synthesis
– Burn hydrocarbon at low pressure
http://cnx.org/contents/4a177b0e-1228-41d4-9d62d4f0a9a3f335@1/Buckyballs:_Their_history_and_
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Carbon Nanotubes
• Single-Walled Carbon Nanotubes (SWCNT; SWNT)
• Multi-Walled Carbon Nanotubes (MWCNT; MWNT)
• Preparation:
– Arc evaporation (plasma arcing)
– Laser ablation
– PECVD
– Electrochemical methods
• Addition of transition metal powder encourages SWNT growth
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Carbon Nanotubes
(a) Armchair
(b) Zigzag
(c) Chiral
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Flavors of nanotubes
• Armchair is
metallic
• Zigzag/Chiral are
semiconducting
(small bandgap)
• Most methods
produce mixture
• Catalysts,
sorting
techniques to
separate
Nature 512, 61–64 (07 August 2014)
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Properties of Carbon Nanotubes
• Mechanical
– Stiff and robust structures
• C-C bonds in graphite (and nanotubes) is the one of
the strongest bonds in nature
– Flexible; do not break when bent
• Conductivity
– Extremely high thermal conductivity
– Extremely high electrical conductivity
• Potential Applications:
- catalysis
- hydrogen storage
- resistors
- flow sensors
- electronic/mechanical devices
- biological cell electrodes
- electron field emission tips
- scanning probe tips
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http://www.rps.psu.edu/hydrogen/form.html
Carbon Nanotube Applications (NEMS)
“Nantero is a nanotechnology
company using carbon
nanotubes for the development
of next-generation
semiconductor devices...
In the field of memory, Nantero is
developing NRAM™, a highdensity nonvolatile Random
Access Memory.”
Cedric – computer made with
SWNT
-align nanotubes
-obtain only semiconducting
morphologies
- 8 micron features
http://www.bbc.com/news/science-environment-24232896
http://www.nantero.com/
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Carbon Nanotube Applications
Gold plate ~ (100 nm)2
attached to outer shell of
suspended MWCNT (on Si
wafer)
“electrostatically rotate the
outer shell relative to the
inner core”
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http://en.wikipedia.org/wiki/Nanomotor
Carbon Nanotube Applications
Nanotechnology 22 (2011) 435704
• Aligned sheet of MWNT, Thermally activated
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Other Organic Molecules
• Small molecules
acetone
• solvents
• metabolites
• reactants or monomers
• Large molecules; “macromolecules”
• biomolecules
• e.g. DNA, proteins, lipids
• carbon nanotubes
• polymers
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Organic Nanotechnology
http://www.nanowerk.com/spotlight/spotid=4343.php
http://www.kurzweilai.net/butterfly-moleculecould-lead-to-new-sensors-photoenergyconversion-devices
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