Towards fractional-order capacitors with broad tunable constant phase angles: Multi-walled carbon nanotube-polymer composite as a case study
Rajab, Karam Hani
Hassan, Ali H.
Salama, Khaled N.
KAUST DepartmentComputer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division
Electrical Engineering Program
SABIC - Corporate Research and Innovation Center (CRI) at KAUST
KAUST Grant NumberRGC/3/2385-01
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AbstractIn this study, multi-walled carbon nanotube (MWCNT) filled Polyevinelidenefluoride-trifluoroethylene-chlorofluoroethylene (PVDF-TrFE-CFE) composites are used to realize fractional-order capacitors (FOCs). A solution-mixing and drop-casting approach is used to fabricate the composite. Due to the high aspect ratio of MWCNTs, percolation regime starts at a small weight percentage (wt%), 1.00 % .The distributed MWCNTs inside the polymer act as an electrical network of micro-capacitors and micro-resistors, which, in effect, behaves like a FOC. The resulting FOCs' constant phase angle (CPA) can be tuned from to by changing the wt% of the MWCNTs. This is the largest dynamic range reported so far at the frequency range from 150 kHz to 2 MHz for an FOC. Furthermore, the CPA and pseudo-capacitance are shown to be practically stable (with less than 1% variation) when the applied voltage is, changed between 500 µV and 5V. For a fixed value of CPA, the pseudo-capacitance can be tuned by changing the thickness of the composite, which can be done in a straightforward manner via the solution-mixing and drop-casting fabrication approach. Finally, it is shown that the frequency of a Hartley oscillator built using an FOC is almost 15 times higher than that of a Hartley oscillator built using a conventional capacitor.
CitationAgambayev A, Rajab KH, Hassan AH, Farhat M, Bagci H, et al. (2018) Towards fractional-order capacitors with broad tunable constant phase angles: multi-walled carbon nanotube-polymer composite as a case study. Journal of Physics D: Applied Physics 51: 065602. Available: http://dx.doi.org/10.1088/1361-6463/aaa4de.
SponsorsThe authors would like to thank the King Abdullah University of Science and Technology (KAUST) and Saudi Basic Industries Corporation (SABIC) for funding this work under Grant No. RGC/3/2385-01.