The interconnected, molecular sized pores of microporous materials as well as of nonporous materials are of great interest for absorption, separation and catalytic applications because of their large accessible surface area. Swift heavy ion (SHI) irradiation is a useful technique for the physical and chemical modifications of the polymers. To obtain calibrated pores in cylindrical shape the etching rate along the tracks should be essentially higher than the etching rate of undamaged polymer. Multiple pores, due to overlapping of the pores and inhomogeneous pore distribution, may arise due to high pore density and non-uniform target thickness. The shape of the pores in the polymers is affected by the conditions of chemical etching used for enlarging the latent track. It is well-established that pore size is the determining parameter for hydrogen storage as well as for nano-filtration. Slow positron beam in addition to Doppler Broadening Spectroscopy (DBS) is a useful technique to evaluate the nanoporosity of polymers. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.