Piezoresistivity in pyrolyzed coconut fiber

Abstract

Pyrolyzed carbon materials give fascinating solutions for many problems in the current research world. The locally available organic wastes can be pyrolyzed and tuned for their properties for various applications. Coconut-based materials such as shell and fiber have shown promising results in different technological applications. However, a detailed study of the structural and property evolution of these materials has not been carried out yet. In this work, the evolution of conductivity and piezoresistivity of coconut fiber-derived carbon is studied. Coconut fiber is pyrolyzed at different temperatures 600 °C, (CCP600) 800 °C (CCP800) and 1000 °C (CCP1000) to produce carbon fiber. Electrical conductivity experiments show differences between CCP600, CCP800 and CCP1000, with CCP600 displaying much lower conductivity at approximately (0.7 S/m) compared to CCP800 (1 × 10³ S/m) and CCP1000 (1.4 × 10³ S/m). Conversely, CCP600 demonstrates impressive piezoresistive characteristics, exhibiting significant resistance changes even under minimal strain. The gauge factor for the coconut fiber-derived carbon was found to be 4.1 for CCP600, 1.0 for CCP800, and 0.3 for CCP1000. Further, the powdered carbon samples show an increase in the gauge factor to a range of 36.8, which makes CCP600 well-suited for sensor applications requiring precise sensing capabilities. The present study suggests that CCP600, with its low cost and ease of fabrication, is a promising material for low-budget sensor applications.