Imaging flow distribution through nanoporous polymer films using bright-field nanoscopy

Abstract

Bright-field nanoscopy (BFN), an optical visualization technique using standard diffraction-limited microscopy, has been used in the past to visualize nanoscale objects such as grain boundaries in single layer graphene and water transport across nanomembranes. Here, we show how BFN can be used to visualize and gather information about water transport networks in porous polymer membranes. We were able to visualize a sub-100 nm network of pores in a polyelectrolyte multilayer using this technique. The extracted pore diameter distribution fitted well to an exponential distribution. Further, the time evolution of pore diameter displayed two distinct regimes consistent with expectations.