Study of Swift Heavy Ion and Gamma Ray Induced Free Volume Changes in Polymeric Materials and their Characterization

Abstract

Ion beam modification is one of the effective ways to modify the chemical and structural properties of materials among the other techniques present such as doping, variation in composition, heat treatment, ion trapping and ion beam mixing etc. Polymeric materials are highly radiation sensitive. The polymeric properties can be modified by radiation treatment such as gamma exposure, electron, proton, ion irradiation and implantation. The energetic swift heavy ions (SHI) deposit extremely high localized density of energy to the material in contrast to electrons and protons. The discrete energy lost results in the formation of several chemical active species like radicals, cations, anions and and#948; rays (secondary electrons) along the polymeric chains. The extent of modification in the polymeric properties depends upon structure of the polymer and nature of the incident ion parameters (charge, mass, energy and fluence). The explanation of these modifications is mainly based upon ion energy loss processes inside the polymer (electronic and nuclear energy loss) and linear energy transfer (LET) of the impinging ion. The electronic energy lost by SHI induces the changes in the surface and bulk properties of the polymers such as defect creation, cross linking, scissoring and degradation of polymeric chains. The polymeric properties can be engineered by ion beam treatment in order to make them functional for desired applications. The ion beam modified polymers have been reported to be used in industrial, electronics, medical and other applications. The use of focused ion beam irradiation to induce the nano- space reactions and formation of nano wires in polymers has been reported. The ion beam has been used for the evolution of nanostructures which are essential in the development of devices that incorporate nano-scale functionality for mechanical, chemical and optical features...