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Questions and Answers
Which characterization technique provides information about the absorption, reflectance, luminescence, and phosphorescence properties of nanoparticles (NPs)?
Which characterization technique provides information about the absorption, reflectance, luminescence, and phosphorescence properties of nanoparticles (NPs)?
What is a primary characteristic that differentiates the optical properties of noble metal nanoparticles (NPs) compared to their bulk form?
What is a primary characteristic that differentiates the optical properties of noble metal nanoparticles (NPs) compared to their bulk form?
Which of the following techniques is least effective for estimating the size of nanoparticles (NPs)?
Which of the following techniques is least effective for estimating the size of nanoparticles (NPs)?
What aspect of nanoparticles affects their physical chemistry across a broad range of applications, including biomedical and environmental uses?
What aspect of nanoparticles affects their physical chemistry across a broad range of applications, including biomedical and environmental uses?
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Which structural characterization technique can provide insights into the bulk properties of nanoparticles?
Which structural characterization technique can provide insights into the bulk properties of nanoparticles?
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Which type of nanoparticle is characterized by being made of globular hollow cages?
Which type of nanoparticle is characterized by being made of globular hollow cages?
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What unique property do metal nanoparticles exhibit due to localized surface plasmon resonance (LSPR)?
What unique property do metal nanoparticles exhibit due to localized surface plasmon resonance (LSPR)?
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Which nanoparticles are typically synthesized through a heat and cooling process?
Which nanoparticles are typically synthesized through a heat and cooling process?
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What is the primary characteristic of semiconductor nanoparticles?
What is the primary characteristic of semiconductor nanoparticles?
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What shapes are commonly associated with polymeric nanoparticles?
What shapes are commonly associated with polymeric nanoparticles?
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Which type of nanoparticles is known for their use in photocatalysis and photo optics?
Which type of nanoparticles is known for their use in photocatalysis and photo optics?
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What type of structure do three-dimensional nanomaterials primarily utilize to prevent aggregation?
What type of structure do three-dimensional nanomaterials primarily utilize to prevent aggregation?
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What is a defining characteristic of metal nanoparticles concerning their elemental composition?
What is a defining characteristic of metal nanoparticles concerning their elemental composition?
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What is the definition of nanomaterials?
What is the definition of nanomaterials?
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Which of the following is a characteristic of nanomaterials at the nanoscale?
Which of the following is a characteristic of nanomaterials at the nanoscale?
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What is the size range for particles classified as nanoparticles?
What is the size range for particles classified as nanoparticles?
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What term is used to describe zero-dimensional objects in nanostructures?
What term is used to describe zero-dimensional objects in nanostructures?
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What is the primary feature of lipid-based nanoparticles?
What is the primary feature of lipid-based nanoparticles?
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In one-dimensional nanostructures, how do electrons behave?
In one-dimensional nanostructures, how do electrons behave?
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Which approach involves modifying bulk materials to obtain the desired size and shape?
Which approach involves modifying bulk materials to obtain the desired size and shape?
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What is usually referred to as the core in a nanoparticle structure?
What is usually referred to as the core in a nanoparticle structure?
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What type of microscopy is primarily used for morphological characterization of nanomaterials?
What type of microscopy is primarily used for morphological characterization of nanomaterials?
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What is an example of a two-dimensional nanostructure?
What is an example of a two-dimensional nanostructure?
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What is the principle behind Scanning Electron Microscopy (SEM)?
What is the principle behind Scanning Electron Microscopy (SEM)?
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Who first used the term “nanotechnology”?
Who first used the term “nanotechnology”?
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Which method is commonly used to produce nanocrystalline structures from microcrystalline structures?
Which method is commonly used to produce nanocrystalline structures from microcrystalline structures?
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What type of information can Transmission Electron Microscopy (TEM) provide?
What type of information can Transmission Electron Microscopy (TEM) provide?
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What is the focus of lipid nanotechnology?
What is the focus of lipid nanotechnology?
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Which of the following best describes the bottom up approach in nanomaterial synthesis?
Which of the following best describes the bottom up approach in nanomaterial synthesis?
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Study Notes
Engineered Nanomaterials - Topic 3, Part II - Polymers
- The word "nanotechnology" was first used by Norio Taniguchi in 1974.
- He used it to describe the precise and accurate tolerances needed in machining and finishing materials.
- The term "nano" comes from the Greek word for dwarf.
- A nanometer (nm) is one billionth of a meter (10-9 meters).
The Scale of Things - Nanometers and More
- Nanomaterials range from 1 to 100 nanometers.
- Examples of natural nanomaterials include butterflies, pollen, and red blood cells.
- Examples of things manmade at nanoscale include quantum corral of 48 iron atoms on a copper surface and carbon nanotubes.
What are Nanomaterials?
- Nanomaterials are materials that have at least one dimension in the nanometric scale.
- Nanotechnology is the understanding and control of matter at dimensions of roughly 1 to 100 nanometers.
Nanomaterials
- Nanoparticles are particles with sizes in the range of 1 to 100 nm.
- Nanotechnology is the application of nanosized particles.
Special in Nanomaterials
- At the nanoscale, physical, chemical, and biological properties of materials differ significantly from the properties of bulk materials or individual atoms and molecules.
- The table shows different side lengths (cm), total surface area (cm2), and corresponding surface energies (J/g).
Nanoparticle Color Absorptions
- The color of nanoparticles depends on their size and shape.
- Gold nanoparticles exhibit a color change depending on their size.
Nanoparticles Structures
- Nanoparticles have three layers: surface, shell, and core.
- The surface layer can be functionalized with different molecules, metal ions, surfactants, and polymers.
- The shell layer is chemically distinct from the core.
- The core is the central part of the nanoparticle.
FE-SEM Micrographs
- Images of nonporous and mesoporous materials (MA-SiO2 NPs).
- Transmission Electron Microscopy (TEM) images are also included.
- The images display different configurations of materials.
Quantum Sizes in Nanostructures
- Zero-dimensional objects: These include nanoparticles, clusters, colloids, nanocrystals, and fullerenes. They contain tens to thousands of atoms. Electrons are confined in all three directions.
- One-dimensional objects: These are cylinder-like objects like wires and tubes with nanoscale diameters and micrometer lengths. Electrons are confined in the transverse dimensions but free to move along the structure.
- Two-dimensional objects: These are thin films with thicknesses in the nanometer range. Electrons behave like bulk material in the two dimensions parallel to the film.
- Three-dimensional objects: The nanomaterials have interconnected macro/mesopores. This maximizes accessible surface area.
Classification of Nanoparticles
- Carbon-based nanoparticles: Fullerenes and carbon nanotubes (CNTs) are major types. Fullerenes are cage-like forms of carbon with pentagonal and hexagonal units.
- Metal nanoparticles: Pure metal precursors with localized surface plasmon resonance (LSPR) characteristics. These show unique optoelectrical properties, particularly in alkali and noble metals (Cu, Ag, Au).
- Ceramic nanoparticles: Inorganic, nonmetallic solids formed via heat and successive cooling. Can be amorphous, polycrystalline, dense, porous, or hollow. They are used in catalysis, photocatalysis, dye degradation, and imaging.
- Semiconductor nanoparticles: Possess wide bandgaps and show significant property changes with bandgap tuning. Important for photocatalysis, photo optics, and electronic devices.
- Polymeric nanoparticles: Typically organic, referred to as polymer nanoparticles (PNPs). Can be matrix particles (solid mass with adsorbed molecules) or nanocapsules (solid mass encapsulated within).
- Lipid-based nanoparticles: Possess a solid lipid core stabilized by surfactants or emulsifiers. Used in drug delivery and RNA release for cancer therapy.
Types of Nanostructures
- 0D: Clusters
- 1D: Nanotubes, fibers, rods
- 2D: Films, coats
- 3D: Polycrystals
Approaches to Nanomaterials Synthesis
- Top-down: Breaking down bulk materials into smaller fragments. Examples include etching and lithography in integrated circuit production. Also, ball milling is used to break microcrystalline structures down to nanocrystalline structures.
- Bottom-up: Building materials from basic components (atoms/molecules) to create nanoscale structures.
Characterization of Nanomaterials
- Morphological characterizations: Techniques like polarized optical microscopy (POM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) are used.
- Structural characterizations: Techniques like X-ray diffraction (XRD), energy-dispersive X-ray (EDX), X-ray photoelectron spectroscopy (XPS), infrared spectroscopy (IR), Raman spectroscopy, Brunauer-Emmett-Teller (BET) analysis, and zeta-potential size analyzer/dynamic light scattering (DLS) are employed.
- Particle size and surface area characterizations: SEM, TEM, XRD, AFM, and dynamic light scattering are used. Zeta potential and DLS are helpful for extremely low levels.
- Optical characterizations: Analysis of absorption, reflectance, luminescence, and phosphorescence properties. Useful for photo-related applications.
Physicochemical Properties of NPs
- Electronic and optical properties: Optical and electronic properties are interdependent. Noble metals (e.g., Au) display size-dependent optical properties and UV-visible extinction bands not found in bulk metals.
- Magnetic properties: Nanoparticles exhibit properties in diverse fields like heterogeneous and homogeneous catalysis, biomedicine, magnetic fluids, data storage, MRI, and decontamination (e.g., water remediation). Ideal size is generally 10-20 nm.
- Mechanical properties: NPs influence fields like tribology, surface engineering, nanofabrication, and nanomanufacturing. Properties include hardness, elastic modulus, adhesion, and friction. Surface coating, coagulation, and lubrication are also influential parameters.
- Thermal Properties: Metal nanoparticles often have higher thermal conductivities compared to fluids in solid form, which can lead to enhanced heat transfer. Conductivities are significantly higher.
Nanomaterials in Nature
- Natural nanomaterials are found in raw materials like plants, animals, and minerals without human modification. Examples of these are visible in biological systems.
Application of Nanomaterials
- Nanomaterials have various applications, including stained-glass windows, paintings, cosmetics, effluent treatment, medicine, sensors, food packaging, concrete, insulation materials, and hard cutting tools.
- The Lycurgus cup (5th century) is an example of a material using nanoparticles.
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Description
Test your knowledge of the various characterization techniques used for nanoparticles. This quiz covers absorption, reflectance, luminescence, and other optical properties, differentiating features of noble metal nanoparticles, and synthesis methods. Understand the critical aspects that influence their applications in various fields.
