Possible correlation between pore architecture and ion transport in supported liquid membranes: Slow positron beam studies

摘要

Depth dependent Doppler broadened measurements have been carried out in commercially available PTFE based supported liquid membranes using Slow Positron Accelerator at Radiochemistry (SPARC). The specified pore dimensions are of 0.2, 0.45, 1.2 and 5 μ that will be referred to as A,B,C & D, respectively. S-parameter and 3γ/2γ ratios as a function of energy or depth are evaluated. Measurements on a non-porous Teflon tape is also carried out as reference. The data has been fitted using VEPFIT to get the diffusion length of positron/positronium. The bulk S-parameters of A & B have quite similar value(0.513-0.515) higher than that for C & D which are 0.504 & 0.509 respectively. SEM studies reveals the texture and pore size distributions to be similar in A&B quite different from that of C&D.