Polyaramid-Based Flexible Antibacterial Coatings Fabricated Using Laser-Induced Carbonization and Copper Electroplating
Emil R. Mamleyev, Fabian Falk, Peter G. Weidler, Stefan Heißler, Sagar Wadhwa, Omar Nassar, C.N. Shyam Kumar, Christian Kübel, Christof Wöll, Monsur Islam, Dario Mager, Jan G. Korvink
Abstract
A method for the fabrication of flexible electrical circuits on polyaramid substrates is presented based on laser-induced carbonization followed by copper electroplating. Locally carbonized flexible sheets of polyaramid (Nomex), by laser radiation, create rough and highly porous microstructures that show a higher degree of graphitization than thermally carbonized Nomex sheets. The found recipe for laser-induced carbonization creates conductivities of up to ∼45 S cm–1, thereby exceeding that observed for thermally pyrolyzed materials (∼38 S cm–1) and laser carbon derived from Kapton using the same laser wavelength (∼35 S cm–1). The electrical conductivity of the carbonized tracks was further improved by electroplating with copper. To demonstrate the electrical performance, fabricated circuits were tested and improvement of the sheet resistance was determined. Copper films exhibit antimicrobial activity and were used to fabricate customized flexible antibacterial coatings. The integration of laser carbonization and electroplating technologies in a polyaramid substrate points to the development of customized circuit designs for smart textiles operating in high-temperature environments.