Temperature Induced Dimensional Tuning and Anomalous Deformation of Micro/Nanopores.

Artificial nanopores have become a common toolbox in nanotechnologies, with dimension and geometry as predominant factors. Most fabrication technologies determine the pore size beforehand, but few exist that enable size-tuning post-manufacturing. In this work, we reported a type of ion track etched micro/nanopores on uniaxially drawn PET foils that enable irreversible thermal shrinkage, thus tuning the pore dimensions by increasing ambient temperatures. Importantly, we found a complex pore deformation process, which for a specific range of pore sizes and temperatures resulted in a peculiar "eye"-shaped appearance of the pore openings. We analyzed the mechanical stresses and theoretically illustrated the complex deformation process by a phase diagram. Temperature-induced dimensional tuning nanopores reduced maximally over 98% of ionic conduction in a single nanopore and 99% of pressure-driven flow in a pore-array membrane within few seconds at 90 °C, which is useful for temperature-modulated mass transport in nanotechnology and energy applications.