Development of piezoelectric coaxial filament sensors P(VDF-TrFE)/copper for textile structure instrumentation

• Piezoelectric coaxial filament for textile structure instrumentation is developed using melt spinning process.
• Coaxial filaments based on P(VDF-TrFE) copolymer and copper filament were polarized by the ISL process.
• Mechanical properties and piezoelectric activity were analyzed.
• Coaxial filament specimens were integrated in textile (fabric) structure.
• Detection capability was verified by connecting a stressed weaving fabric to an oscilloscope.

Coaxial filaments based on Poly (vinylidene fluoride-co-trifluoroethylene) and copper filament was developed, their mechanical properties characterized. They were then instrumented in textile structure and their detection capabilities were observed.P(VDF-TrFE)/copper coaxial filaments were obtained by a melt spinning process, the mechanical drawing applied at the end of spinning process enabled the increasing of the crystalline β phase from 43% for the copolymer in pellet shape to 52% for the developed coaxial filament of 250 μm in diameter. Coaxial filaments surfaces and sections have been analyzed with a scanning electron microscope. The mechanical properties have been quantified by tensile analyses. Coaxial filaments were polarized by the ISL process in order to correlate the level of the polarization with the piezoelectric activity. The textile instrumentation was tested by the integration of some samples in the weft direction of a weaving structure using an industrial weaving machine (Muller NCE 10). An example of electrical signal delivered by integrated filament in textile when subjected to strain and stress actions is shown.