Microcontact printing of copper and polypyrrole on fluoropolymers

This paper describes the use of microcontact printing (μCP) to form micrometer-scale patterns of copper on poly(tetrafluoroethylene) (PTFE), and illustrates the use of these patterned surfaces as substrates for electrodeposition of polypyrrole (PPy) sensor structures. A patterned elastomeric stamp was used to deliver a nitrogen-containing silane coupling agent to the argon plasma-pretreated PTFE surface. The surface was subsequently activated by PdCl2, allowing the selective activation via the formation of Pd-N complex. Patterning of copper structures with feature sizes of 50-200 μm was achieved by immersing the activated surface into an electroless copper plating bath. Surface chemistry was investigated after each surface modification and deposition step using X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (TOF-SIMS). This study demonstrates a soft lithography approach for the fabrication of patterned copper and PPy structures on flexible PTFE films, offering new opportunities for the creation of polymer-based electronic devices and sensor arrays.