Fabrication of functional micro- and nanoporous materials from polymers modified by swift heavy ions

Similar to ionizing radiation with low LET, swift heavy ions (SHI) produce excitation and ionization as they pass through a polymer. Due to a high local confinement of dissipated energy, SHI produce continuous damage trails (latent tracks) that consist of highly degraded material with increased chemical reactivity. As a result, the polymers irradiated with heavy ions are anisotropic and highly heterogeneous on the nanometer scale. The permeability of ion-irradiated polymer foils can be considerably improved using the exposure to ultraviolet radiation and the extraction of radiolysis products from the tracks. Chemical etching is used to further modify the structure of ion-irradiated polymers and produce micro- and nanostructured membranes. Different methods of ion track etching enable the fabrication of asymmetric nanopores whose shape and dimensions can be controlled at will. In electrolyte solutions, the asymmetric track-etched nanopores possess unique transport properties, such as ionic gating and ionic rectification, which provides a platform for versatile applications that hold potential including biomimetic nanofluidic devices, energy conversion, biochemical sensors, and others.