chapter
Thin Films: Polyaniline and Poly(3-methylthiophene)
ByG.B.V.S. Lakshmi, Shumaila, Sameen Ahmed Khan, Azher M. Siddiqui
Pages 10

Plasma polymerization is a procedure in which gaseous monomers, stimulated through a plasma, condense on freely selectable substrates as high cross-linked layers. As monomer molecules become shattered in plasma into reactive particles, there remain only partially preserved chemical structures of the output gases in the product, which results in cross-linked and disordered structure. Structural preservation and cross-linking gradients can be controlled through process parameters, such as pressure, working gas flow, and applied electrical output. Plasma polymerization uses plasma sources to generate a gas discharge that provides energy to activate or fragment the gaseous or liquid monomer, in order to initiate polymerization and hence achieve polymer thin films. By selecting the monomer type and the energy density per monomer, the chemical composition and structure of the resulting thin film can be varied in a wide range. Suitable modifications are done in a radio-frequency (RF) sputtering setup to facilitate synthesis of polyaniline thin film by RF plasma polymerization process. Swift heavy ion (SHI) irradiation of polymers modifies the material properties dramatically. SHI irradiation induces interesting changes in polymer properties by changing their structural properties. An increase in hardness, strength, wear resistance, electrical conductivity, density, chain length, crystallinity, solubility, and improvements in the optical transmission properties of the polymers has been reported. These changes depend upon the sample parameters, such as composition, molecular weight, temperature, and ion beam parameters, such as energy, mass, and fluence.