Conduction in Organic Molecule

Hey frnds, all we know that Plastics are totally insulating material, but if i say that conduction is also possible in plastics........then can u believe? But yes this is true. Don't u want to know that how this happen......here is answer of your question.
Plastic is also known as Polymer.The fundamental property that allows polymer / organic molecules to conduct electronic charge is molecular conjugation, i.e. the presence of alternating single and double bonds between covalently bound carbon atoms.Conjugation causes the delocalization of one of the four valence electrons of each carbon atom that participates in the conjugated system, and this allows the efficient transport of electronic charge along a conjugated molecule.

  Highly conjugated organic materials have the potential to work as semiconductors because of their strong π-orbital overlap. In organic solids, the carbon atom forms a tetrahedral SP³ Hybridized single bond configuration, but in double bond it has the configuration of SP²-Pz and in triple bond it has SP-Pz-Py configuration . The intra-molecular interactions between the atoms lead to a splitting of the initially degenerated 2Pz energy levels into a bonding and an anti-bonding molecular π orbital. 

The resulting bonding orbital takes the electrons known as HOMO(Highest Occupied Molecular Orbit) while the anti-bonding orbital remains empty LUMO (Lowest Unoccupied Molecular Orbital ). HOMO is equivalent to valance band and LUMO, to conduction band. The gap between HOMO and LUMO is known as Energy band gap.