This article presents the fabrication and characterization of poly dimethylsiloxane/carbon nanofiber (CNF)-based nanocomposites. Although silica and carbon nanoparticles have been traditionally used to reinforce mechanical properties in PDMS matrix nanocomposites, this article focuses on understanding their impacts on electrical and thermal properties. By adjusting both the silica and CNF concentrations, 12 different nanocomposite formulations were studied, and the thermal and electrical properties of these materials were experimentally characterized. The developed nanocomposites were prepared using a solvent-assisted method providing uniform dispersion of the CNFs in the polymer matrix. Scanning electron microscopy was employed to determine the dispersion of the CNFs at different length scales. The thermal properties, such as thermal stability and thermal diffusivity, of the developed nanocomposites were studied using thermogravimetirc and laser flash techniques. Furthermore, the electrical volume conductivity of each type of nanocomposite was tested using the four-probe method to eliminate the effects of contact electrical resistance during measurement. Experimental results showed that both CNFs and silica were able to impact on the overall properties of the synthesized PDMS/CNF nanocomposites. The developed nanocomposites have the potential to be applied to the development of new load sensors in the future.
ARTICLE HISTORY
In this paper a nanocomposite system is proposed to accurately measure pressure generated by normal force. The strain sensing function is achieved by correlating the piezoresistance variations to the normal force applied on the sensing area. Due to the conductive network formed by carbon nanofibers (CNFs) and the tunneling resistance change between neighboring CNFs the electrical resistance measured using the four-probe method shows a clear correlation with the load conditions. In order to improve the piezoresistivity, CNF are uniformly dispersed in PDMS using a solvent assisted ultra-sonication method. The proposed nanocomposite based strain sensor is experimentally characterized under both quasi-static and cyclic load conditions.
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