Polyaramid-Based Flexible Antibacterial Coatings Fabricated Using Laser-Induced Carbonization and Copper Electroplating

A method for the fabrication of flexible electrical circuits on polyaramid substrates is presented, based on laser-induced carbonisation followed by copper electroplating. Locally carbonised flexible sheets of polyaramid (Nomex), by laser radiation, creates rough and highly porous microstructures that show a higher degree of graphitisation compared to thermally carbonised Nomex sheet. The found recipe for laser-induced carbonisation creates conductivities of up to \SI{\sim 45}{\siemens\per\centi\m}, thereby exceeding that observed for thermally pyrolysed materials (\SI{\sim 38}{\siemens\per\centi\m}) and laser carbon derived from Kapton using same laser wavelength (\SI{\sim 35}{\siemens\per\centi\m}). The electrical conductivity of the carbonised 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 customised flexible antibacterial coatings. The integration of laser carbonisation and electroplating technologies in a polyaramid substrate points to the development of customised circuit designs for smart textiles operating in high temperature environments.