Bendable piezoresistive sensors by screen printing MWCNT/PDMS composites on flexible substrates

This paper presents piezoresistive sensors array, developed by screen printing of polymer nanocomposites based on multiwall carbon nanotubes (MWCNT) in poly (dimethyl-siloxane) (PDMS) matrix. The sensors are printed on 25 μm thick flexible polyethylene terephthalate (PET) substrate in the form of segmental arrays with parallel plate structures, whereby, MWCNT/PDMS nanocomposites layer is sandwiched between two printed silver plates of 1×1 mm² area each. Force concentrator structures, printed on separate PET sheet, are adhered to the bottom substrate with proper alignment to the sensory cells. Three different polymer nanocomposites (by wt. %) of carbon nanotubes (MWCNT) in PDMS matrix have been investigated here for possible application as a tactile sensor in an electronic skin for robots and general purpose applications. The change in resistance value is observed when structures are subjected to normal compressive forces as well as when they are bent.