In this paper, we investigated the relations between dispersion of CNTs (carbon nanotubes) and electrical conductivity in the CNT/PVDF (polyvinylidene fluoride) composite film. By adding hydrophobic CNTs as filler into the PVDF matrix, we fabricated hydrophobic and electrically conducting polymer coating film. Dispersion of CNTs in the CNT/PVDF composite film plays a significant role in terms of electrical conductivity and wetting property. Spray coating method was used to form the CNT/PVDF composite films by injecting the dispersed CNTs in the PVDF solution with different weight ratios from 0.7 wt% to 7 wt%. We investigated the electrical properties and contact angles of the CNT/PVDF composite films with the CNT concentration. Finally we discussed the conducting mechanism and feasibility of the CNT/PVDF composite film for the conducting polymer films.

In this paper, we fabricated flexible antenna radiator using the CNT/PVDF (carbon nanotube /polyviny lidene fluoride) composite film. We used polymer film as a matrix material for the flexible devices, and introduced CNTs for adding conductivity into the film resulting in obtaining performances of the antenna radiator. Spray coating method was used to form the CNT/PVDF composite radiator, and pattern formation of the radiator was done by shadow mask during the spray coating process. We investigated the electrical properties of the CNT/PVDF composite films with the CNT concentration, and also estimated the radiator performance. Finally we discuss the feasibility of the CNT/PVDF composite radiator for the flexible antenna.

In this paper, we propose a enhanced anti-corrosion property of the ground system by coatingthe CNT/PVDF composite film on it. Polymer material used for preventing the corrosion of groundsystem is polyvinylidene fluoride (PVDF), and conducting filler for obtaining conductivity of the compositefilm is multi-walled carbon nanotubes (MWCNTs). The MWCNTs were dispersed in the organic solventof methyl ethyl ketone 2-butanone (MEK) with different concentration ratios, and the PVDF was solvedin the MEK solvent with constant concentration ratio of 1 wt%. The CNT/PVDF composite solution wasperpared by mixing and re-dispersing the CNT solution and the PVDF solution. Finally, the CNT/PVDFcomposite films were fabricated by the spray coating method using the above composite solution. Electrical conductivity, surface states, and anti-corrosion property of the CNT/PVDF composite filmscoated on the Cu substrate were evaluated. We found that the CNT/PVDF composite film showedrelatively low resistance, hydrophobic surface state, and chemical stability. Consequently, we couldimprove the anti-corrosion property and maintain the electrical conductivity of the ground system bycoating the CNT/PVDF composite film on it.

The carbon nanotube / poly-vinylidene fluoride (CNT/PVDF) composite films for the nano-generator devices were fabricated by spray coating method using the CNT/PVDF solution, which was prepared by adding PVDF pellets into the CNT dispersed N-Methyl-2-pyrroli-done (NMP) solution. The flexible CNT/PVDF composite films were investigated by the scanning electron microscopy, which revealed that the CNTs were uniformly dispersed in the PVDF matrix and thickness of the films was approximately 20 jim. Fourier transform infra-red spectra were used to investigate crystal structure of the as-spray-coated CNT/PVDF films, and we found that they revealed extremely large portion of the f3 phase PVDF. The capacitance of the CNT/PVDF films increased by adding CNTs into the PVDF matrix, and finally saturated. However, the resistance didn`t show any saturation effect in the CNT concentration range of 0- 4 wt%. Finally, the resulting nano-generator devices revealed reasonable current output after given mechanical stress.

Abstract: Carbon nanotubes (CNT) / polyvinylidene fluoride (PVDF) piezoelectric composite films for nanogenerator devices were fabricated by spray coating method. When the CNT/PVDF mixture solution passes through the spray nozzle with small diameter by the compressed nitrogen gas, electric charges are generated in the liquid by a triboelectric effect. Then randomly distributed {3 phase PVDF film could be re-oriented by the electric field resulting from the accumulated electrical charges, and might be resulted in extremely one-directionally aligned 13 phase PVDF film without additional electric field for poling. X-ray diffraction patterns were used to investigate crystal structure of the CNT/PVDF composite films. It was confirmed that they revealed extremely large portion of the f3 phase PVDF crystalline in the film. Therefore we could obtain the poled CNT/PVDF piezoelectric composite films by the spray coating method without additional poling process.