Micropatterned stretchable circuit and strain sensor fabricated by lithography on an electrospun nanofiber mat

This paper describes a novel approach for composite nanofiber mats and its application to fabricate a strain sensor. Electrospun poly(4-vinylpyridine) (P4VP) nanofiber mats are micropatterned by a lithographic approach that includes selective oxidation of the nanofibers and removal of unreacted fibers. The P4VP/HAuCl4 complex is converted to P4VP/Au composites by chemical reduction. We investigate the electrical resistivity of the composite mats according to the number of complexation-and-reduction cycles, the thickness of the fiber mats, and the annealing temperatures which control the percolation of the Au nanoparticles in the fiber mats. Nozzle printing of a polymeric solution on the patterned nanofiber mats simply produces an array of strain-sensitive and strain-invariant units. The patterns demonstrate high strain-sensing performance without any mechanical and electrical failure over 200 bending cycles in the strain range of ε<0.17.