Study of neutralization kinetics in charged polymer-metal nanocomposite systems by photoemission spectroscopy

In case of photoelectron spectroscopy of an insulating material the data obtained from the charged surface are often distorted due to differentially charged surface domains. Recently we have developed a controlled surface neutralization technique to study the kinetics of the surface charging. Here we demonstrate the application of the technique to study the neutralization kinetics of both thick and thin films of charged polymer-metal nanocomposite material using photoemission. Neutralization kinetics of grounded and floated pure polymer thin films was also studied. It was observed that for the thick sample the transition of positively charged domains to overcompensated ones occurs through percolation. In case of grounded thin films the growth of overcompensated domains exhibit a linear behavior followed by saturation. When electrons appear at both surfaces of a floated thin film, the neutralization kinetics show a completely different behavior. Present investigation indicates that for thin films of insulating materials appearing to be neutral in presence of an electron source, controlled neutralization technique may be an important tool to distinguish between presence of multiple chemical species and differential charging.