On 3D Printing of Primary Recycled Polyvinylidene-Fluoride-Based Miniaturized, Flexible, and Wearable Sensor

Polyvinylidene fluoride (PVDF) is one of the established thermoplastics for bio-sensing applications, and several studies have been reported on the use of this material as tactile sensors. But hitherto little has been reported on 3D printing of primary (1°) recycled PVDF-based sensors in lower C-band applications (for miniaturization, flexibility, and wearability features). This study reports the 3D printing of 1° recycled PVDF-based flexible and wearable miniaturized sensors for lower C-band applications. The 1° recycled PVDF substrate (for the sensor) was 3D printed by using fused filament fabrication. The ring resonator technique and transmission line method were used to ascertain the dielectric constant (3.3) and loss tangent (~ 0.003) of the substrate. The prepared sensor has a return loss of ≈ − 20 dB at 4.1 GHz and shows good conformability for bending up to 70 mm replicating the human body part. The specific absorption rate was recorded to be 0.6W/kg. Further, the negligible variation in S-parameter during the in vitro testing validates the adopted method and supports the use of miniaturized sensors for lower C-band applications.