Iraqi - New materials

Question 1

Processibility of conjugated polymers

Answer 1

Conjugated polymers could be considered rigid rods
–> Solubility is an issue
There is a requirement of a precursor route OR solubilising side groups for better interaction with polymers

Question 2

Applications of doped conjugated polymers

Answer 2

Antistatic materials
Electromagnetic shielding
Anticorrosion Coatings
Electrolytic capacitors
Batteries
Smart Windows
Sensors

Question 3

Applications of undoped conjugated polymers

Answer 3

LEDs
Photodiodes
Solar Cells
Lasers
Field-Effect Transistors
Non-linear optical material
Sensors

Question 4

PEDOT-PSS

Answer 4

Very stable in doped state –> 100 h in air at 100 degrees gives no change in conductivity
Used as:
- Photographic film Agfa - antistatic coating
- Electrode for solid electrolyte capacitor
FUTURE: Antistatic coating for cathode array tubes; corrosion protection; Hole injection layer in LEDs

Question 5

Polyalinine

Answer 5

Solution and melt processible and forms good blends with polymers, such as polyethylene

Question 6

What is the purpose of blending polyaniline?

Answer 6

Blends combine electrical and optical properties of polyalinine with mechanical properties of common bulk polymers

Question 7

PLEDs

Answer 7

Glass base
Indium Tin Oxide layer
Conjugated polymer layer 50-100 nm
Ca/Al metal cathode
Light is emitted through glass layer
Injection of holes and electrons from opposite side of polymer film creates excitons which radiatively decay with emission of light

Question 8

Link between polymer structure and colour of emitted light

Answer 8

Least conjugated; Highest band gap; BLUE

Planar chain; low band gap; RED