Polyacetylene

Organic polymers that conduct electricity are called conducting polymers.

Such compounds may have metallic conductivity or can be semiconductors.

The biggest advantage of conductive polymers is their processability, mainly by dispersion.

In 1970 H.shirakawa reported high molecular weight polyacetylene film by passing dry acetylene gas over Ziegler-Natta catalyst of titanium tetrabutoxide triethyl aluminium in toluene at -78℃.

It was obtained on the surface of the catalyst.

And also in the two forms known as cis and trans.

(1) Is cis polyacetylene.(2) Is trans polyacetylene.

The role of a dopant is to either add or remove electrons to the polymer.

It is of two kinds:

(1) Oxidative or p-doping. (2) Reductive or n-doping.

The oxidizing agents for P-doping are like iodine vapours,I₂ dissolved in CCl₄ , HBF₄, HClO₄ , Br₂..etc.

(CH)n → (CH)n ⁺ I₃⁻

The conduction in this type of doping increases up to 10⁵ s/cm.

The reducing agents for n-doping are like Na metal ,FeCl₂, lithium metal ,sodium naphthalide..etc.

(CH)n → (CH)⁻ Na⁺

Negative charge resonates throughout the

chain and transferred to neighbouring chains through Na⁺ during conduction.

For making rechargeable batteries. Used as sensors for phenol , O₂..etc at low

concentrations. For manufacture of transistors ,LEDs, lasers

and solar cells. In telecommunication systems In the construction of photovoltaic cells.

Solar cell

Light-emitting diodes

Shield for computer screenagainst electromagnetic"smart" windowsradiation