Functionalization of nanochannels by radio-induced grafting polymerization on PET track-etched membranes

• Irradiated PET foils with swift-heavy ions were etched and grafted in a step-by-step process.
• Grafting polymerization was performed on the remaining active sites after etching.
• Track-etched PET membranes were fluorescently labeled by chemical functionalization.
• Functionalized track-etched PET membranes were analyzed by fluorescence and confocal microscopy.

The application of swift-heavy ion bombardment to polymers is a well-established technique to manufacture micro- and nanopores onto polymeric films to obtain porous membranes. A few years ago, it was realized that, during ion bombardment, the high energy deposition along the ion path through the polymer reached cylindrical damage regions corresponding to the core trace and the penumbra. After the etching procedure, there are still enough active sites left in the penumbra that can be used to initiate a polymerization process selectively inside the membrane pores.In this study, we report the grafting polymerization of glycidyl methacrylate onto etched PET foils to obtain functionalized nanochannels. Grafted polymers were labeled with a fluorescent tag and analyzed by different fluorescence techniques such as direct fluorescence, fluorescence microscopy and confocal microscopy. These techniques allowed identifying and quantifying the grafted regions on the polymeric foils.