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The reduction of graphene oxide (GO) generally involves the use of chemical agents or high-temperature processes, raising concerns about safety, environment, and energy consumption issues. While self-propagating reduction of GO films was observed to produce functional rGO, potentially mitigating these issues, its process control has not yet been extensively explored. This study proposes a controllable self-propagating reduction of GO films by adjusting the base temperature of the films within low values (50 C-90 C). For understanding the reduction mechanism, the speed and peak temperature of the moving reduction front were measured in real-time, and a heat transfer model was proposed to explain the self-propagating reduction based on the observed reduction kinetics. When used for binder-free supercapacitor electrodes, the rGO films exhibited competitive specific capacitance (112 F/g) and excellent capacitance retention (94%) after 10 000 cycles. This study opens a new avenue for efficiently exploiting the self-propagating reduction of GO films to produce high-quality rGO at a minimal energy cost.

Conductive fibers are essential building blocks for implementing various functionalities in a textile platform that is highly conformable to mechanical deformation. In this study, two major techniques were developed to fabricate silver-deposited conductive fibers. First, a droplet-coating method was adopted to coat a nylon fiber with silver nanoparticles (AgNPs) and silver nanowires (AgNWs). While conventional dip coating uses a large ink pool and thus wastes coating materials, droplet-coating uses minimal quantities of silver ink by translating a small ink droplet along the nylon fiber. Secondly, the silver-deposited fiber was annealed by similarly translating a tubular heater along the fiber to induce sintering of the AgNPs and AgNWs. This heat-scanning motion avoids excessive heating and subsequent thermal damage to the nylon fiber. The effects of heat-scanning time and heater power on the fiber conductance were systematically investigated. A conductive fiber with a resistance as low as ~2.8 Ω/cm (0.25 Ω/sq) can be produced. Finally, it was demonstrated that the conductive fibers can be applied in force sensors and flexible interconnectors.

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