The use of supercritical CO2 as a green solvent was materialized to synthesize well-defined poly (vinyl pivalate)[1].In this study,activator regenerated electron transfer atom transfer radical polymerization[2,3] of vinyl pivalate was investigated employing different catalytic systems for producing polymers with narrower molecular weight distribution (MWD).Herein,a series of polymerization reactions were also carried out at different temperatures,pressures,and feed concentrations to ensure the optimum condition.It is reported that CuCl2 catalyst with Cu0 wire was found to be the most efficient catalytic system as better control over MWD (PDI < 1.4) was obtained.Significant enhancement of deactivation rate constant in the presence of zerovalent copper may be opted as the potential reason behind this.Consequently,the experimental molecular weight was also in good agreement with the theoretical one.