Relaxation processes and conduction behaviour in PVDF-TrFE and KNN-based composites

Ferroelectric Properties of Polymer-Semiconductor Hybrid Material or Composite under Optical Excitation

Polymer-semiconductor hybrid materials or composites have been investigated with respect to their microstructure, optical, photoconductive, and ferroelectric properties. For this purpose, either CdSe quantum dots or (Cd:Zn)S microparticles were dispersed in poly(vinylidenefluoride-trifluoroethylene) solution and hot pressed to films. In both material systems, the electrical conductivity and the polarization behavior could be controlled by the intensity of the optical excitation. The simultaneous high optical transparency of the CdSe quantum-dot-based hybrid materials makes them particularly interesting for applications in the field of flexible, high-resolution sensors.

Multimodal Fibrous Static and Dynamic Tactile Sensor

A highly versatile, low-cost, and robust tactile sensor capable of acquiring load measurements under static and dynamic modes employing a poly(vinylidene fluoride-co-trifluoroethylene) [P(VDF-TrFE)] micronanofiber element is presented. The sensor is comprised of three essential layers, a fibrous core P(VDF-TrFE) layer and two Ni/Cu conductive fabric electrode layers, with a total thickness of less than 300 μm. Using an in situ electrospinning process, the core fibers are deposited directly to a soft poly(dimethylsiloxane) (PDMS) fingertip. The core layer conforms to the surface and requires no additional processing, exhibiting the capability of the in situ electrospinning fabrication method to alleviate poor surface contacts and resolve issues associated with adhesion. The fabricated tactile sensor displayed a reliable and consistent measurement performance of static and instantaneous dynamic loads over a total of 30 000 test cycles. The capabilities and implications of the presented tactile sensor design for multimodal sensing in robot tactile sensing applications is further discussed and elucidated.