This study reports on the effects of nucleating agents on morphology, charging, and electrostatic filtration performance of polypropylene meltblown webs. Two commercial nucleating agents, DMDBS (3:2, 4-bis(3,4-dimethyldibenzylidene) sorbitol) and NA11 (sodium 2,2'-methylene-bis(4,6-di-tertbutylphenyl)-phosphate) were compared. It is hypothesized that faster solidification brought about by the addition of the nucleating agents may be responsible for the slight increase in fiber diameter and concomitant reduction in web solidity. Samples were charged at room temperature as well as at elevated temperatures. Upon thermal charging, significant enhancement in the electrostatic potential and filtration performance of the webs was observed. Particularly, the stability of electrostatic filtration performance was found to be promising with the addition of these polarizable additives. Dielectric spectroscopy tests confirmed an increase in capacitance for samples containing nucleating agents. (C) 2013 Society of Plastics Engineers