AbstractAn efficient method for biomolecular patterning based on ion irradiation-induced graft polymerization has been demonstrated. Ion irradiation resulted in the formation of active species on the polymer surface, which in turn was utilized for graft polymerization of acrylic acid. Polymerization conditions were optimized to yield maximum grafting degree of poly(acrylic acid) onto the PTFE. The application of this platform for biomolecular patterning has been successfully demonstrated by patterning DNA and streptavidin on the poly(acrylic acid)-grafted PTFE substrates. This method is capable of grafting various functional groups such as amide and alcohol onto a variety of polymer substrates.