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Questions and Answers
How does the number of surface atoms change with reducing particle size in nanomaterials?
How does the number of surface atoms change with reducing particle size in nanomaterials?
What effect does the reduction in particle size have on the band gap of nanoparticles?
What effect does the reduction in particle size have on the band gap of nanoparticles?
In nanomaterials, what happens to the melting point as the size of the particles decreases?
In nanomaterials, what happens to the melting point as the size of the particles decreases?
What aspect of a material does 'elongation to failure' measure?
What aspect of a material does 'elongation to failure' measure?
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How does the catalytic activity of catalysts change with the surface area of nanomaterials?
How does the catalytic activity of catalysts change with the surface area of nanomaterials?
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What factor increases with a reduction in the size of diamond nanoparticles?
What factor increases with a reduction in the size of diamond nanoparticles?
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What is a unique property of graphene?
What is a unique property of graphene?
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What is a common property of nanomaterials?
What is a common property of nanomaterials?
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What is the bond angle in the structure of graphite?
What is the bond angle in the structure of graphite?
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What is a use of graphite?
What is a use of graphite?
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What happens to the surface area of a material as its size decreases?
What happens to the surface area of a material as its size decreases?
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What is a characteristic of single-walled carbon nanotubes?
What is a characteristic of single-walled carbon nanotubes?
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What is the typical size range of nanotechnology?
What is the typical size range of nanotechnology?
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What is the shape of the molecule of fullerene C60?
What is the shape of the molecule of fullerene C60?
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What is the length-to-diameter ratio of carbon nanotubes?
What is the length-to-diameter ratio of carbon nanotubes?
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How are single-walled nanotubes (SWNTs) and multi-walled nanotubes (MWNTs) categorized?
How are single-walled nanotubes (SWNTs) and multi-walled nanotubes (MWNTs) categorized?
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What is the force that holds carbon nanotubes together in 'ropes'?
What is the force that holds carbon nanotubes together in 'ropes'?
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What is the shape of the nanostructure of nanofibers?
What is the shape of the nanostructure of nanofibers?
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Study Notes
Nanoparticle Properties
- As particle size decreases, the percentage of atoms on its surface increases: 30nm (5%), 10nm (20%), 3nm (50%)
- Increased surface area leads to increased catalytic activity of catalysts
- Emission can be tuned by controlling the size of nanoparticles (e.g., CdSe nanoparticles or quantum dots)
Bandgap and Absorption Thresholds
- Bandgap increases with reducing particle size (e.g., CdS nanoparticles)
- Calculated bandgaps and absorption thresholds for CdS of different sizes are shown in the table
Strength and Ductility
- Yield strength is the stress at which a specific amount of plastic deformation is produced
- Elongation to failure is a measure of the ductility of a material
- Breaking through the strength-ductility trade-off dilemma in an AlSi-based casting alloy
Carbon Nanotube (CNT) Properties
- Extremely strong, stiff, and relatively ductile
- Single-walled carbon nanotubes are the strongest known material
- Very low densities, with the ultimate fiber being 100 times stronger than steel and six times lighter
Graphite and Graphene
- Graphite: crystalline form of carbon with covalent bonding and a 120° bond angle
- Graphene: a two-dimensional, atomic-scale, hexagonal lattice with unusual properties (e.g., 200 times stronger than the strongest steel, efficient heat and electricity conduction, near transparency)
Nanotechnology and Nanomaterials
- Nanotechnology: science, engineering, and technology conducted at the nanoscale (1-100 nanometers)
- Nanomaterials can have very different properties from bulk materials
- Properties of nanomaterials include increased surface-to-volume ratio, surface effects, and increased catalytic activity
- Classification of nanomaterials: nanoparticles, nanostructures, nanofibers, nanowires, nanotubes, nanothin films, and surface coatings
Fullerenes
- Fullerenes: a new allotrope of carbon with a structure of a truncated icosahedron (e.g., C60 molecule, 0.7 nm in diameter)
- Named Buckminster fullerene, with a soccer ball-like structure
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Description
Explore the extraordinary properties of Carbon Nanotubes (CNT), known for their strength, stiffness, and low densities. Learn about the structure of graphite, a crystalline form of carbon with various applications like solid lubricants, nuclear reactor moderator, electrodes, and pencil leads.
