Radiation tolerance in polymeric dielectrics by small-molecule doping, Part I: Dopant uptake as a function of temperature, time, and chemistry

The doping of Mylar® film (composed of semi-crystalline poly(ethylene terephthalate)) with small-molecule electron traps results in a high-quality dielectric film with excellent radiation tolerance. This paper, the first of two, investigates the doping process as small molecules are implanted into the film from a solution of ethylene glycol over time. A series of fluorenone-based dopants are investigated, functionalized by nitro or cyano groups. The concentration of dopant in the Mylar® is a strong function of time, temperature, and solution concentration. Doping is ineffective below the glass transition temperature of the polymer. The chemical functionality of the dopant had a strong effect on the doping process, with additional nitro or cyano groups leading to enhanced film concentrations.