Fonksiyonel polimer kompozitlerden üretilen esnek elektroniklerin elektromekanik algılama özellikleri

Polymers that are lightweight, easily processable, and have different morphological, thermal, mechanical, and electrical properties, are generally preferable for various applications such as electronics, automotive interiors, outdoor products, biomedical, etc. thanks to their tunable properties. With the incorporation of filler/additive materials, some properties of the polymeric matrix can be changed. For instance, for the applications those require electrical conductivity, electrically conductive polymer composites are fabricated with the addition of conducting filler material into the insulating polymer matrix. In this case, not only filler properties but also matrix properties are of significance in terms of the final properties of the conductive composites. In this work, to observe the effect of filler and matrix type on piezoresistive sensing performance, different nanocomposites were prepared. Two different poly[styrene-b-(ethylene-co-butylene)-b-styrene] (SEBS) with different block ratios (styrene to ethylene-butylene ratio (S/EB): 13/87 and 19/81) and three different filler systems were used including carbon black (CB), vapor grown carbon nanofibers (VGCNFs), and mixture of CB and VGCNF (VGCNF:CB = 1) at the filler concentration between 0.5 to 6.5 wt% for the first time in the literature. In the first step of this study, flexible conductive polymer composites were fabricated and their morphological, electrical, mechanical properties and piezoresistive sensing performance were investigated depending on filler type, filler concentration, and matrix type. Regarding to the percolation behavior, composite sets were found to be used as strain sensors. However, the sensitivity of hybrid filler-based nanocomposites was higher that could be given as the novelty of the study. The nanocomposite with 3.5 wt% CB-VGCNF hybrid filler showed the gauge factor (GF) around 333 that was one of the highest sensitivity obtained for SEBS based hybrid nanocomposites in the literature. The reason was the unique conductive network formation with the addition of VGCNF into CB. Not only decrease in percolation concentration was observed compared to CB-filled nanocomposites but also formation of new unique conductive network morphology was achieved that was highly sensitive to strain deformation because of additional junctions between low and high aspect ratio fillers. In the final step of the study, a textile-based sensor was fabricated from the hybrid nanocomposites by coating on the fabric surface, and its morphological, and electromechanical properties were also characterized. The GF of the textile-based piezoresistive strain sensor was found around 108 that was also reported for the first time in the literature.