Fabrication of Freestanding Nanoporous Polyethersulfone Membranes Using Organometallic Polymer Resists Patterned by Nanosphere Lithography

Freestanding nanoporous polysulfone membranes are fabricated using nanosphere lithography, in which colloidal silica particles act as a template for the organometallic etch resist, which is composed of poly(ferrocenylsilanes). As shown in the figure, the membranes are robust enough to be removed from the silica wafers where they were produced. They can subsequently be used to separate particles of different sizes.