NANOCHEMISTRY INTRO

• GIVE PROPERTIES OF THE LYCRUGUS CUP

  1.   Made from dichroic glass

  2.  Gold and silver nanoparticles in colloidal suspension

  3.  Shows different colours depending on reflection of light. Red when lit from behind and green when lit from front

  4.  Most likely made from accidental contamination with these dust particles
• GIVE PROPERTIES FOR MEDIEVAL STAINED GLASS


  1.  Made from trapped gold nanoparticles

  2. Ruby red = gold NP

  3. Yellow = silver NP
• GIVE PROPERTIES OF RENAISSANCE CERAMICS


  Made from copper and silver NP for iridescence
• GIVE PROPERTIES OF DAMASUCS STEEL

  made from carbon nanowires/tubes for strength
• RICHARD FENYMANS VISION


  'there's plenty of room at the bottom' in 1959 predicting future for nanotechnology with atom arrangement for new technology/devices and how these can be layered in the correct way
• DEFINE NANOSCIENCE


  the study of phenomena/manipulation of materials at nanoscale (1-100nm)
• DEFINE NANOCHEMISTRY


  branch of nanoscience focusing on manipulation including synthesis and characterisation at nanoscale
• DEFINE NANOTECHNOLOGY


  application of nanoscience to create new material and devices
• DEFINE NANOPARTICLES


  defined by ISO as nano objects with all 3 dimensions under 100nm
• DEFINE NANOSTRUCTURES


  aggregates of nanoparticles bonded together
• DEFINE NANOCOMPOSITES 


  systems with packed nanoparticles affecting macroscopic properties
• IUPAC OF NANOPARTICLES

  particles of any shape with dimensions in the 1×10−9 and 1×10−7 m range
• PARTICLE SIZES: fine, ultrafine, coarse


  1. Ultrafine = 1 – 100 nm

  2.  Fine = 100 – 2,500 nm

  3.  Coarse = 2,500 – 10,000 nm
• EXAMPLES OF ORGANIC AND INORGANIC NP


  1.  Inorganic – gold NP, Qdots

  2.  Organic – liposomes, micelles
• DEFINE NANOMATERIALS


  they have at least one dimension that measures between 1 and 100 nm
• NAME THE 4 DIMENSIONS

  1. 0D – all dimensions at nanoscale e.g. nanoparticles

  2. 1D – one dimension at macroscale e.g. nanofibers/tubes

  3. 2D – two dimensions at macroscale e.g. thin sheets/films/graphene

  4. 3D – all dimensions at macroscale – bulk e.g.  foams
• HOW DOES SIZE AFFECT NANOPARTICLES

  nanoparticles have a large surface area to volume ratio compared to bulk materials. this means more atoms on their surface are exposed and in turn, increase reactivity.
• HOW CAN THE SURFACE OF NANOPARTICLES BE STABILISED

  by adding surfactants of ligands which can also affect reactivity
• HOW CAN SHAPE AFFECT NANOPARTICLES

  different shapes/sizes can affect the plasmonic properties which affects how they absorb and scatter light which is useful in bioimaging
• GIVE AN EXAMPLE OF NP scattering

  gold NPs can have different shapes which affect their different colours/characteristics in solution. ratio, shell thickness and gold conc can affect how they absorb/scatter light = different colours. this is useful in biomedicine
• WHAT IS PLASMON RESONANCE

  when a metal is exposed to light, the free electrons in the metal oscillate in resonance with the electromagnetic field of light
• WHAT IS SURFACE PLASMON RESONANCE


  when this type of resonance occurs at the surface of a nanoparticle. when light is exposed to a nanoparticle, the conduction band electrons (electrons that can move freely within metal) oscillate collectively. this oscillation leads to a dipole oscillation along the direction of electric field of the light
• HOW TO OBSERVE SPR / MAX FREQUENCY


  the amplitude of oscillation reaches a specific maximum frequency . this is the point of resonance and results in strong absorption/scattering of light and can be observed in an absorption spectrum using a UV-VIS spectrometer.
• WHAT CAN AFFECT THE INTESITY OF SPR PEAK


  size, shape and composition of nanoparticle
• WHAT IS LSPR


  LOCALISED surface plasmon resonance for metallic NPs like gold/silver that are smaller than wavelength of incident light that causes free electrons to vibrate and confined only to the space where the light is hitting and not spreading out.
• NAME THE APPLICATIONS OF GOLD NPs IN BIOTECHNOLOGY

  chemical sensing, drug and gene delivery
• NAME THE APPLICATIONS OF GOLD NPs IN CATALYSTS

  co catalysts, pollution mitigation
• NAME 3 SYNTHESIS METHODS OF GOLD NPs

  colloidal suspension, seed mediated synthesis, SMAD
• HOW DOES COLLOIDAL SUSPENSION WORK

  first observed by michael farraday. the chemical reduction of a gold precursor usually HAuCl4. it was then refined by Turkevich who used tridsodium citrate to reduce HAuCl4 in water and then refined by frens. it produced Gold NPs between 10 - 40 nm. this is a bit large and is less monodisperse and irregular shaped
• HOW DOES SEED MEDIATED SYNTHESIS WORK


  was used for Gold NPs bigger than 50 nm diameter to improve monodisperse and shape. large gold Nps made by reducing gold HAuCl4 using capping agents such as surfactants, ligands, dendrimers or polymers to confine the grown in the nanometer regime
• WHY STABILISE SURFACE OF GOLD NPs


  to prevent aggregation of particles and can help them disperse better in solution
• ROLE OF SURFACTANTS


  surface active agents that stabilise the surface by reducing surface tension and preventing crystal growth. they create uniform size distributions, dispersity and shape. Thiol (-SH) is usually used for surface bonding
• 3 METHODS OF GOLD CHARACTERISATION


  DLS - particle size distribution, TEM - visualisation of nps, UV-VIS - light absorption and luminescence of Gold NPs SPR
• WHAT IS DLS


  also known as QELS - QUASI ELASTIC LIGHT SCATTERING. brownian motion causes light to scatter at different intensities. stokes einsten euqation can be used to measure this.