nano materials 01

Types of Nanomaterials (Sigma Aldrich)

Dr. Rafael Vargas Bernal Materials Engineering Department

Academic Group: “Advanced Materials Applied to Engineering”

Contents

• Nanoparticles: Materials by Application

• Nanopowders and Nanoparticle Dispersions

• Nanoparticles: Metals and Metal Alloys

• Nanoparticles: Oxides, Nitrides, and Other Ceramics

• Nanowires

• Surface Functionalized Nanoparticles

• Quantum Dots

Contents

• Carbon Nanomaterials

• Gold Nanoparticles

• Nanominerals: Nanoclays

• Dendrimers

• Mesoporous Materials

• Silsesquioxanes: POSS Nanohybrids

NANOPARTICLES: MATERIALS BY APPLICATION

BIOMEDICAL MATERIALS

Biomedical Materials

• Nanomaterials, those with at least one dimension of less than 1000nm, have shown unique benefits as components in a number of high technology applications. One of the best studied of these is nanomedicine where nanoparticles are used in applications including biological imaging, tissue scaffolding, bioassays, drug delivery and photodynamic therapy.

Biomedical Materials

• Nanomaterials with biomedical activity include iron oxide, silver and gold as well as biocompatible supports such as carbon and silica nanoparticles which can be functionalized to interact with specific biomolecules. One such support material, hydroxyapatite a naturally occurring and biocompatible calcium phosphate, has shown to enhance the growth of bone cells.

Biomedical Materials

• Research in biological imaging and labeling has shown that biocompatible nanoparticles can be effective imaging agents due to their small size and unique properties. Iron oxide nanoparticles have been shown to be degradable in vivo and can be used to label cells in magnetic imaging studies using MRI (Magnetic Resonance Imaging).

Biomedical Materials

• Gold and silver nanoparticles have shown to exhibit surface plasmon resonance, or ordered movement of electrons at the particle surface on exposure to light which can be utilized in optical imaging and labeling by enhancing their fluorescencent properties.

Biomedical Materials

• Surface enhanced Raman spectroscopy using gold nanoparticles has further shown to be effective in the imaging and detection of tumor cells. Gold and silver nanoparticles conjugated to biomolecules can also be used to label specific receptors inside cells, while silver nanoparticles have also shown to be toxic to bacteria in vitro.

MAGNETIC MATERIALS

Magnetic Materials

• Magnetic materials are essential components of modern technology with applications ranging from recording media to medical imaging. Magnetic nanomaterials, those with at least one dimension below 1 μm, are proving to be equally versatile with unique applications and properties. These have been studied for applications including biomedical imaging, medical diagnostics and magnetic memory devices.

Magnetic Materials

• One important magnetic property on the nanoscale is superparamagnetism which can lead to particles with much higher magnet susceptibilities than in traditional paramagnets. The investigation and modeling of superparamagnetism in nanoscale iron oxides has led to an enhanced understanding of magnetic properties at the nanoscale.

Magnetic Materials

• The most common nanomagnets are ferrites, including both binary and complex oxides of iron. These materials have well understood magnetic properties and have been extensively used in biomedical applications.

Magnetic Materials

• Ferrite nanoparticles have been studied in applications including drug delivery, biological imaging, including as MRI contrast agents, and conjugation of biological molecules. One advantage of iron oxide nanoparticles is that they can be easily functionalized through the attachment of organic or biological molecules to the particle surface which can increase the selectivity and bonding strength of the particle and target.

Magnetic Materials

• These have a number of applications outside of biological systems by their high surface area and ability to disperse in solution can provide unique benefits. Such particles serve as recyclable supports in heterogeneous catalysis allowing easy separation of the catalyst post reaction with an induced magnetic field. They are effective for the removal of contaminants from water using functionalized magnetic nanoparticles.

PHOSPHORS AND PHOSPHOR HOSTS

Phosphors and Phosphor Hosts

• Nanoparticles can exhibit enhanced properties including luminescence and phosphorescence compared to bulk materials making them ideal for solid state lighting and optical labeling. Nanomaterials have been studied both as nanophosphor dopants and host materials. The most commonly studied luminescent and phosphorescent nanomaterials consist of lanthanides and wide band-gap oxides.

Phosphors and Phosphor Hosts

• Lanthanide materials are one of the most common classes of phosphors in solid state lighting and medical imaging. Yttrium aluminum oxide or YAG is a commonly used substrate for both phosphor and laser materials and recent studies have demonstrated the use of nanoscale YAG powders as a host for lanthanide dopants such as ytterbium and neodymium oxides.

Phosphors and Phosphor Hosts

• Wide band gap oxides such as zinc oxide nanoparticles have shown photo-luminescent properties leading to potential applications in biological applications such as cell labeling. Zinc and silicon oxides have also been tested as nanoscale phosphor host materials for dopants including copper, manganese and praseodymium.

STRUCTURAL MATERIALS AND COATINGS

Structural Materials and Coatings

NANOPOWDERS AND NANOPARTICLE DISPERSIONS

Nanopowders and Nanoparticle Dispersions

• Nanopowders are solid powders of nanoparticles, often containing micron-sized nanoparticle agglomerates. These agglomerates can be redispersed using, for example, ultrasonic processing. Nanoparticle dispersions are suspensions of nanoparticles in water or organic solvents.

Nanopowders and Nanoparticle Dispersions

• These dispersions can be used as-is, or diluted with suitable (compatible) solvents. Nanoparticles in dispersions can sometimes settle upon storage, in which case they can be mixed before use. Some surface-functionalized nanoparticles (for example silver and gold) are available as solutions in water or organic solvents. These are "true" solutions, which should not settle or exhibit phase separation if properly stored.

NANOPARTICLES: METALS AND METAL ALLOYS

Nanoparticles: Metals and Metal Alloys

NANOPARTICLES: OXIDES, NITRIDES, AND OTHER CERAMICS

Nanoparticles: Oxides, Nitrides, and Other Ceramics

NANOWIRES

Nanowires

• One dimensional nanostructures such as nanowires have been shown to display unique properites owing to their high aspect ratios. Nanowires have applications in electronics, energy generation, composite formation and plasmonic devices.

SURFACE FUNCTIONALIZED NANOPARTICLES

Surface Functionalized Nanoparticles

QUANTUM DOTS

Quantum Dots

• Quantum dots are nanocrystals exhibiting both photo- and electroluminescence properties. They feature bright emissions, narrow size distributions, high purity, and good quantum yields. They are available in both organic and aqueous formulations and have unique properties for applications that include LEDs, solid state lighting, displays, photovoltaics, transistors, quantum computing, medical imaging, biosensors, among many others.

Alloyed Quantum Dots

CdS Type Quantum Dots

CdSe Type Quantum Dots

Core-Shell Type Quantum Dots

CARBON NANOMATERIALS

Carbon Nanomaterials

• Carbon Nanotubes

• Fullerenes

• Graphene and Graphene Oxide

CARBON NANOTUBES

Carbon Nanotubes

• Since their discovery in 1991 by Ijima, single wall carbon nanotubes have stimulated a great deal of activity in both the global research community and industry, and have inspired much investment in manufacturing methods, characterization and application development. The reasons for this are quite clear, given the remarkable properties these materials possess and the diversity of distinct species, each with its own unique variations in their properties.

Carbon Nanotubes

• Single-Walled Carbon Nano Tubes (SWCNTs) and Multi-Walled Carbon Nano Tubes (MWCNTs) share some similarities, but also striking differences. Of the two carbon nanotube types, SWCNTs are the more remarkable.

Carbon Nanotubes

• They have outstanding strength, can be highly electrically conducting or semiconducting, may be as thermally conductive at room temperature as any other known material, have a very large surface area per unit mass, and have unique optical properties. This range of unique properties has opened the doors to advances in performance in a wide range of materials and devices.

FULLERENES

Fullerenes

GRAPHENE AND GRAPHENE OXIDE

Graphene and Graphene Oxide

• Graphene is a carbon based material that can be viewed as a one atom thick sheet of graphite and has been investigated intensely in recent years following a report by Novoselov et al. on its isolation and measurement of its unique electronic properties. Quickly after its initial discovery, graphene was used to make electronic devices for a variety of applications.

Graphene and Graphene Oxide

• Because high quality sheets of graphene is often prepared by chemical vapor deposition (CVD), which requires expensive equipment, many groups have looked at using graphene oxide as a solution processable alternative for the preparation of graphene like materials.

Graphene and Graphene Oxide

• Indeed, graphene oxide can be reduced in solution and as a thin film using a variety of reducing conditions, and reduction converts the graphene oxide into a material that has a large enhancement in electrical conductivity.

Graphene and Graphene Oxide

• In addition to its use in making reduced graphene oxide for electronic devices, it has been used in catalytic oxidation, biotechnology and as a surfactant. Graphene is also related to carbon nanomaterials such as carbon nanotubes and fullerene.

GOLD NANOPARTICLES

Gold Nanoparticles

NANOMINERALS: NANOCLAYS

Nanominerals: Nanoclays

DENDRIMERS

Dendrimers

• Dendrimers are highly branched, star-shaped macromolecules with nanometer-scale dimensions. They have three components: a central core, an interior dendritic structure (the branches), and an exterior surface with functional surface groups. The varied combination of these components yields products of different shapes and sizes with shielded interior cores that are ideal candidates for applications in both biological and materials sciences.

Dendrimers

• While the attached surface groups affect the solubility and chelation ability, the varied cores impart unique properties to the cavity size, absorption capacity, and capture-release characteristics. Applications highlighted in recent literature include drug delivery, gene transfection, catalysis, energy harvesting, photo activity, molecular weight and size determination, rheology modification, and nanoscale science and technology.

Dendrimers

• Monodisperse dendrimers are synthesized by step-wise chemical methods to give distinct generations (G0, G1, G2, ...) of molecules with narrow molecular weight distribution, uniform size and shape, and multiple (multivalent) surface groups Z. Dendrons are monodisperse wedge-shaped sections of dedrimers with a single focal point reactive function. Hyperbranched polymers are polydisperse dendritic macromolecules synthesized by lower-cost polymerization methods.

Dendrimers

MESOPOROUS MATERIALS

Mesoporous Materials

SILSESQUIOXANES: POSS® NANOHYBRIDS

Silsesquioxanes: POSS® Nanohybrids

• Hybrid inorganic–organic composites are an emerging class of new materials that hold significant promise. Materials are being designed with the good physical properties of ceramics and the excellent choice of functional group chemical reactivity associated with organic chemistry.

Silsesquioxanes: POSS® Nanohybrids

• New silicon-containing organic polymers, in general, and polysilsesquioxanes, in particular, have generated a great deal of interest because of their potential replacement for, and compatibility with silicon-based inorganics in the electronics, photonics, and other materials technologies.

Silsesquioxanes: POSS® Nanohybrids

• Hydrolytic condensation of trifunctional silanes yields network polymers or polyhedral clusters having the generic formula (RSiO1.5)n. Hence, they are known by the "not quite on the tip of the tongue" name silsesquioxanes. Each silicon atom is bound to an average of one and a half (sesqui) oxygen atoms and to one hydrocarbon group (ane). Typical functional groups that may be hydrolyzed/condensed include alkoxy- or chlorosilanes, silanols, and silanolates.