Nanomaterial

Question 1

nanoparticle

Answer 1

cluster of atoms and molecules in nanoscale region acting as a building unit

Question 2

quantum dot

Answer 2

in case of metals, nanoparticle is known as quantum dot

Question 3

natural nanoscale materials

Answer 3

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

Question 4

nanofabrication in nature

Answer 4

1) colours on butterfly, peacock
2) lotus effect
3) gecko and lizard foot

Question 5

history of nanomaterial

Answer 5

1) colours in medieval cathedrals
2) lycurgus cup
3) damascus sword

Question 6

nanotechnology

Answer 6

ability to work at atomic, molecular and sub molecular levels to create and use material structures, devices and systems with new properties and functions

Question 7

properties that change in nanotech

Answer 7

1) thermal
2) mechanical
3) optical
4) electrical
5) magnetic
6) colour

Question 8

surface plasmon resonace

Answer 8

distance between particles affects colour

Question 9

examples of property change at nanoscale region

Answer 9

1) opaque Cu became transparent
2) inert Pt become catalyst
3) stable Al become combustibility
4) water becomes sticky viscous fluid

Question 10

revolutionary of nanotechnology in physical tech

Answer 10

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

Question 11

Fullerene

Answer 11

allotrope of C consisting of spherical, ellipsoidal or cylindrical arrangements of dozens of C atoms

Question 12

2 types of fullerenes

Answer 12

spherical, cylindrical

Question 13

structure of spherical fullerene

Answer 13

20 hexagonal, 12 pentagonal rings

sp2

Question 14

structure of cylindrical fullerenes

Answer 14

rolled up sheets of C hexagons
C-C distance of about 0.14nm
sp2

Question 15

classification of C nanotubes

Answer 15

1) single walled

2) multi walled

Question 16

properties of fullerenes

Answer 16

1) high strength
2) low molecular weight
3) density half of Al
4) exhibit metal like conductor, semiconductor and insulator properties with changing diameter

Question 17

applications of fullerene

Answer 17

1) satellites and space crafts
2) base balls, bats etc
3) flat panel displays

Question 18

classification of nanostructured materials according to Siegel

Answer 18

0D
1D
2D
3D

Question 19

current nanomaterials are classified into

Answer 19

C based
Metal based
nanopolymers or dendrimers
nanocomposites

Question 20

2 approaches in synthesis of nanomaterials

Answer 20

bottom up

top down

Question 21

methods for nanoparticle synthesis

Answer 21

physical
chemical
biological

Question 22

advantages of chemical methods of synthesis

Answer 22

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

Question 23

applications of nanomaterials

Answer 23

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

Question 24

scanning electron microscope

Answer 24

produces images of a sample by scanning the surface with focused beam of electrons

Question 25

principle of SEM

Answer 25

electrons interact with atoms producing signals which contain info about surface topography and composition

Question 26

back scatter electrons

Answer 26

incidental electrons reflected backwards which provide composition data related to element and compound detection

Question 27

advantages and disadvantages of SEM

Answer 27

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

Question 28

applications of SEM

Answer 28

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