Conducting polymers

Organic polymers are generally used as insulators in the electrical connections due to their poor electrical conductivity.

However electrical conductivity of the organic polymers like polyacetylene can be increased by the factor of 1012 to about 103 Siemens/cm when it doped with the electron doner such as an alkaline metal ion or an electron acceptor such as arsenic penta-fluoride.

Other conducting polymers are polyaniline, polydiacetyline, polythiosphere, polypyrrole etc. such polymers which are made conducting are called as advanced polymeric is materials or conducting polymers.

An organic polymer with highly delocalized pie electron system having conductance of the order of a conductor is called a conducting polymer.

Application - as cathodes and solids electrolytes in batteries for automotive and other uses, in variable transmission windows, electrochromic displays, sensors, L.E.D. and non-linear optical materials, conductive paints, low-current wires etc.

Polymers for medicine and surgery

They are termed as Biomaterials which can be implanted in the body or used in diagnostic, surgical and therapeutic applications without any harm to blood, bones and muscles. They are made from polymers, metals and ceramics.

Requirements for biomedical polymers-

• They should be bio compatible,

• They should have purity and reproducibility,

• They should have optimum physical and chemical properties,

• They should deplete electrolytes in the body,

• They should have good fabrication property and stability.

Uses -

PMMA- contact lenses

POLYPROPYLENE- heart walls, blood filters.

ACRYLIC HYDROGEL- grafting

SILICONE RUBBER- heart walls, drain tubes

SILICONE POLYMER RUBBER - outstanding chemical inertness to body fluids, nontoxic, flexible for use in heart valves, blood filters, artificial heart, vascular tubing.