Ferroelectric hybrid fibers to develop flexible sensors for shape sensing of smart textiles and soft condensed matter bodies

Abstract

Piezoelectric fibers are widely used in composites for actuator and sensor applications due to its ability to convert electrical pulses into mechanical vibrations and transform the returned mechanical vibrations back into electrical signal. They are beneficial for the fabrication of composites especially 1–3 composites, active fiber composites (unidirectional axially aligned PZT fibers sandwiched between interdigitated electrodes and embedded in a polymer matrix) etc, with potential applications in medical imaging, structural health monitoring, energy harvesting, vibration and noise control. However, due to the brittle nature of PZT fibers, maximum strain is limited to 0.2% and cannot be integrated into flexible sensor applications. In this contribution, a new approach to develop flexible ferroelectric hybrid fibers for soft body shape sensing is investigated. Piezoelectric particles incorporated in a polymer matrix and extruded as fiber, 0–3 composite in fibrous form is studied. Commercially obtained calcined PZT and calcined BaTiO3 powders were used in the unsintered form to obtain flexible soft condensed matter ferroelectric hybrid fibers. The extruded fibers were subjected to investigation for their electromechanical behavior as a function of electric field. The hybrid fibers reached 10% of the maximum polarization of their sintered counterpart.

Enhancing dielectric properties of barium titanate macrofibers

“…[17] In this contribution, BT macrofibers were fabricated using thermoplastic ceramic processing. [18][19][20] Due to their high intrinsic properties, BT nanofibers have been employed as ferroelectric fillers in the nanocomposites to improve the final dielectric properties while typically a polymer material is used as the matrix. The effect of BT nanofibers in ferroelectric macro structures has not been investigated so far.…”

“…A low shear mixing process, developed at Empa, was used for the thermoplastic extrusion of BaTiO3 macrofiber. [19,20] All feedstocks were formulated with 30 vol% of BT powder (Ticon F, Ferro Electronic Materials, Niagara Falls, NY, USA) and 20 vol% BT nanofibers calcined at different temperatures, along with 40 vol% thermoplastic binder, ethylene-vinyl acetate…”

“…Figure 2: Schematic of Ferrofib used for ferroelectric and piezoelectric measurement and sample holder[20] …”

Robotics: Science preceding science fiction

“…For example, reinforcing a polymeric matrix with short fibers that display intrinsic shape-changing actuation has resulted in flexible ferroelectric composite fibers suitable for robotic systems. 67 Along with sensing capabilities, morphing and actuation can be intentionally programmed (Figure 4c) through local composite designs.…”

Mechanical and electromechanical properties of piezoelectric ceramic fibers drawn by the alginate gelation method

“…A novel piece of equipment (FerroFib) developed in collaboration with EMPA and aixACCT System GmbH was utilized for ferroelectric and electromechanical characterization of individual fibers. A schematic of the modified device used for measurement was reported previously, while a description of the sample holder is reported elsewhere . The fibers were sliced into small pieces of 2.5 mm and mounted vertically on a polymethyl methacrylate disc.…”