nanotechnology validation Flashcards by Dana Langridge

describe the structure and bonding of fullerenes

Structure: ‘cage structure’ of carbon atoms that resembles a soccer ball

Bonding:
very little attraction between molecules – weak intermolecular forces

each carbon atom is covalently bonded to 3 other atoms

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what are the properties of fullerenes

High MP (sublimes at 800K)

Soft

Semiconductor of heat and electricity

**other properties are normal CMS properties

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describe the structure and bonding of diamond

Structure: Each carbon atoms is covalently bonded to 4 other atoms

Bonding: 3D arrangement called a tetrahedron

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describe the properties of diamond

High melting point (>3550˚C)

Hard

Non-conductors of heat & electricity

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describe the structure and bonding of graphite

Structure:
flat 2D sheets of interlocking hexagonal rings called graphene

Graphite consists of multiple layers of graphene stacked on top of one another with weak bonds between them

bonding:
Each carbon atom is covalently bonded to 3 other atoms

1 valence electron from each carbon atom remains delocalised

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what are the properties of graphite

High melting point

Soft

Good conductor of heat and electricity

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what is nanotechnology

Study and application of structures between 1 and 100 nanometres in size by controlling and manipulating the structures size and shape at the nanoscale

involves molecular sized machines and processes, using nanoparticles

Applies in many scientific fields: chemistry, biology, physics

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give a brief history of the development of nanotechnology

Idea born in 1959 from physicist Richard Feynman exploring idea of building things at atomic and molecular level

Nanotechnology began 1981, IBM scientists built the first scanning tunnelling microscope, allowing us to see a single atom

Further developments allow us to capture images at the atomic level

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what are nanoparticles

particles ranging from 1 to 100 nanometres in diameter

usually contain only a few hundred atoms

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what are some key properties of nanoparticles

being extremely small in size ( between 1 and 100
nanometres)(1nm = 1 billionth of a metre)
high surface area to volume ratio than its bulk
materials - more surface area available for
interactions with other materials

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what is the quantum effect

Different colours produced by solutions due to the prescence of nanosized particles called quantum dots

e.g. zinc oxide are white opaque solids that give excellent UV protection at bulk scale. When used in the form of nanoparticles, they become invisible while still providing UV protection.

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how do nanoparticles differ from the bulk material of which they are made

differ in reactivity

differ in colour

differ in melting point

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how do nanoparticles differ in reactivity from the bulk material of which they are made

This is because they differ in the number of atoms that they’re composed of:
- Nanoparticles usually contain few to a few thousand atoms, as oppose to their bulk materials which may contain billions

This causes nanomaterials to behave differently than their bulk materials, such as in chemical reactions
E.g. gold isn’t usually used as a catalyst for chemical reactions but when it’s broken down to approximately 5 nanometres it can act as a catalyst and do things like oxidizing carbon monoxide

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how do nanoparticles differ in colour from the bulk material of which they are made

due to quantum effect

This is dependent on the size of the nanoparticles (quantum dots)

electron cloud surrounding a nanoparticle will absorb different wavelengths of light than its bulk material, therefore making it appear a different colour

e.g. zinc oxide are white opaque solids that give excellent UV protection at bulk scale.
When used in the form of nanoparticles, they become invisible while still providing UV protection.

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how do nanoparticles differ in melting point from the bulk material of which they are made

Nanoparticles will have a lower melting point

Relates to the number of exposed atoms on the surface of nanoparticles

With a greater number of atoms exposed, heat can break the bond between nanoparticles at lower temperatures

The smaller the particle, the lower its melting point

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describe the structure and bonding of graphene

Single-atom-thick layer of graphite

Carbon atoms arranges in hexagons

Strong covalent bonds between each carbon atoms

Sheets are loosely bonded together

what are the properties of graphene

high MP and BP

good conductor of heat and electricity

very strong

what are some applications of graphene

Used in electronic for flexible, foldable devices

Used in sensors as explosive and gas sensing

Used in energy harvesting and storage: improves energy capacity and charge rate in rechargeable batteries

Used in food packaging as gas barriers

describe the structure and bonding of carbon nanotubes

Cylindrical molecules consisting of rolled up sheets of graphene

Hollow interior

Can be single walled or multi walled

Length can reach several micrometres or even milometers

Bonded with sp2 bonds (extremely strong form of molecular attraction)

what are the properties of carbon nanotubes

extremely hard

good conductors of heat and electricity

light weight

what are some applications of carbon nanotubes

Electrical devices

Biosensors

Lithium ion batteries

White light sources

describe the structure and bonding of quantum dots

2 – 10 nm in size

Made from various metal sulfides or selenides

what are quantum dots

Nanoparticles that produce different colours in solutions

range from 2 - 10 nm in size

When ultra-violet light is shone onto a sample a colour is produced due to the quantum dot size

(smaller = blue/purple, larger = red)

what are the properties of quantum dots

Semiconductors of heat and electricity

Non-soluble in water

what are some applications for quantum dots

Biological tracers due to stability and bright and varied colours May be applied in the future in technology of quantum computing due to electrical properties used in TV displays for bright and vibrant colour

describe the structure and bonding of nanosized silver

Smaller than 100nm 20 – 15000 silver atoms

what are the properties of nanosize silver

Antibacterial effects Good conductors of electricity Differing optical properties: varying absorption and scattering properties when exposed to different wavelengths of light

list some applications for nanosize silver

Antibacterial uses – sterilising consuming and medical equipment e.g. textiles, food storage bags, refrigerator surfaces Used as a catalyst in dyes and chemical reactions Sensors – colorimetric sensing

what are some potential everday material applications for nanotechnology

Nanoscale additives or surface treatment of fabrics can help body armour resist wrinkling, staining and bacterial growth Clear nanoscale film on glasses, computers and windows can make them self-cleaning, water and residue repellent and anti-reflective Nanostructured ceramic coating exhibits a greater toughness than conventional coatings from machines, reducing wear-and-tear

what are some potential electronic applications for nanotechnology

used in ultra high-definition displays and televisions using quantum dots to produce more vibrant colours while being more energy efficient Flexible and foldable electronics are being developed, used in smartphones and e-reader displays Nanotechnology is being used in flash memory chips in smartphones and thumb drives

what are some potential medical/therapeutic applications for nanotechnology

Better imaging and diagnostic tools potentially help deliver medication directly to cancer cells and minimize the risk of damage to healthy tissue potentially improve vaccines and vaccine delivery without needles

what are some potential energy applications for nanotechnology

used in solar panels to convert sunlight to electricity more efficiently, creating inexpensive solar power used in developing batteries that are quicker-charging, lighter-weight, more efficient and have higher power density used to make windmill blades longer, stronger and lighter than other blades to increase the amount of electricity generated

what are some potential environmental remediation applications for nanotechnology

could help meet the need for affordable, clean drinking water through rapid, low cost detection and treatment of impurities in water nanopore membranes have been developed for energy efficient desalination of water Nanoparticles are being developed to clean industrial water pollutants in ground water through chemical reactions. This process would be cheaper than pumping water from the ground for treatment.

explain what is meant by the 'precautionary principle'

Rather than releasing new chemical substances and waiting for potential damage to take place, precautionary principle calls for more research into harmful effects before products are released. set of guidelines used for assessing precautionary steps to reduce potential harm when developing nanotechnology Guidelines allow for a range of interpretations underpins the system for chemicals in the European Union

what are some potential health risks associated with nanotechnology

Nanoparticles are cytoxic and genotoxic - Nanoparticles inter the body through inhalation, injection into bloodstream and can pass through the skin - Due to their small size they have the ability to penetrate your blood-brain barrier They can also interact with proteins and enzymes and later gene expression - This results in biological changes in tissues, organs, cells and proteins - E.g. workers exposed to brick dust or glass fibre particles should take precautions by wearing breathing masks

what are some potential environmental risks associated with nanotechnology

Nanoparticles can be ecotoxic Nanoparticles can be harmful to aquatic animals, being absorbed into the eggs, gills, brain and blood of certain types of fish