Dispersion of hydrophobic conductive carbon black (CB) in polytetrafluoroethylene (PTFE) emulsion through liquid bridges and fabrication of PTFE/CB composite film for triboelectric nanogenerators

Abstract

Polytetrafluoroethylene (PTFE) is a highly electronegative material that is widely used in Triboelectric nanogenerators (TENGs). However, due to the ultralow surface energy of PTFE, it is difficult to achieve a stable and even dispersion of hydrophobic carbon black in the PTFE emulsion. In this study, a novel method was used to achieve a stable and uniform dispersion of hydrophobic carbon black in the PTFE emulsion. An interfacial modifier was added to form liquid bridges between PTFE emulsion particles. The hydrophobic carbon black was then dispersed among these liquid bridges, resulting in its uniform distribution within the aqueous emulsion. The addition of 0.75 wt% CB resulted in a 4.6-fold increase in open-circuit voltage and a 3.5-fold increase in short-circuit current density compared to pure PTFE. Moreover, after 10000 cycles, the open-circuit voltage remained mostly unchanged, indicating that it has great potential for use in wearable devices.