Nanomaterial Flashcards
nanoparticle
cluster of atoms and molecules in nanoscale region acting as a building unit
quantum dot
in case of metals, nanoparticle is known as quantum dot
natural nanoscale materials
1) human and animal bodies to control systems and proteins
2) important functions in organisms
3) volcanic ash, smoke etc
4) body of yeast and bacteria
5) aquatic colloidal matter
6) bipolymers and clays
nanofabrication in nature
1) colours on butterfly, peacock
2) lotus effect
3) gecko and lizard foot
history of nanomaterial
1) colours in medieval cathedrals
2) lycurgus cup
3) damascus sword
nanotechnology
ability to work at atomic, molecular and sub molecular levels to create and use material structures, devices and systems with new properties and functions
properties that change in nanotech
1) thermal
2) mechanical
3) optical
4) electrical
5) magnetic
6) colour
surface plasmon resonace
distance between particles affects colour
examples of property change at nanoscale region
1) opaque Cu became transparent
2) inert Pt become catalyst
3) stable Al become combustibility
4) water becomes sticky viscous fluid
revolutionary of nanotechnology in physical tech
1) safe and affordable space travel
2) materials 100 times stronger than steel
3) no more polln , automatic clean up
4) molec food synthesis to end famine and starvation
5) more molecular manuf systems
Fullerene
allotrope of C consisting of spherical, ellipsoidal or cylindrical arrangements of dozens of C atoms
2 types of fullerenes
spherical, cylindrical
structure of spherical fullerene
20 hexagonal, 12 pentagonal rings
sp2
structure of cylindrical fullerenes
rolled up sheets of C hexagons
C-C distance of about 0.14nm
sp2
classification of C nanotubes
1) single walled
2) multi walled
properties of fullerenes
1) high strength
2) low molecular weight
3) density half of Al
4) exhibit metal like conductor, semiconductor and insulator properties with changing diameter
applications of fullerene
1) satellites and space crafts
2) base balls, bats etc
3) flat panel displays
classification of nanostructured materials according to Siegel
0D
1D
2D
3D
current nanomaterials are classified into
C based
Metal based
nanopolymers or dendrimers
nanocomposites
2 approaches in synthesis of nanomaterials
bottom up
top down
methods for nanoparticle synthesis
physical
chemical
biological
advantages of chemical methods of synthesis
1) simple
2) inexpensive
3) low temp
4) doping is possible
5) high quantity of nanomaterials are obtained
6) variety of sizes and shapes
7) self assembly or patterning
applications of nanomaterials
bacteria sensors adding boron or gold smaller transistors electrodes in ultra capacitors rapid disease diagnosis replacement of broken bones flexible battery production of cartilage clothing chemotherapy drugs photo catalysts flexible solar cells
scanning electron microscope
produces images of a sample by scanning the surface with focused beam of electrons
principle of SEM
electrons interact with atoms producing signals which contain info about surface topography and composition
back scatter electrons
incidental electrons reflected backwards which provide composition data related to element and compound detection
advantages and disadvantages of SEM
Advantages: 3D topographical imgs fast and easy to operate data is available in digital form Disadvantages: expensive and large special training required risk of radiation
applications of SEM
life sciences, bio, medical etc.
in material science, for research, qual control, failure analysis
to characterise nanowires and their gas sensing behaviour
speedy accurate measurement of compsn of semi conductors
criminal and forensic investig
geological sampling
medical science
