The focus of this paper is to investigate the electrical conductivity and the mechanical properties of single-walled carbon nanotubes/polycarbonate composites. Two different direct incorporating methods were applied. In the first method PC and SWCNTs were mixed with different ratios in a small scale conical twin screw extruder. Here, additional variations in the feeding of the filler material were tested in order to improve the state of dispersion of the melt mixing method. The second one is the coagulation method, here, the filler material was suspended and the polymer material was dissolved in liquid organic substances. The mechanical properties were examined by tension tests and by measuring the Vickers hardness. It should be stressed, that the nanofiller material was provided in large batches (m > 100 g) and extensively mechanically homogenized in order to eliminate quality fluctuations and density differences in the SWCNT occurrences. The filler material was synthesized in a Krätschmer reactor (carbon arc). After homogenization, the nanomaterial was characterized. Based on this the SWCNT content was estimated to be between 30 and 40%, which is usual for arc discharge material.

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Microfluidic devices based on the electrowetting principle, more specifically electrowetting on dielectric, were fabricated using transparent single-walled carbon nanotube films as electrodes. The films were spray coated on glass and polyethylene terephalate substrates. The transmittance and sheet resistance remain unchanged after patterning the films using typical photolithography and plasma etching. Operation of water droplets over the patterned nanotube electrodes was demonstrated, and the performance was found to be comparable to that over the usual metal electrodes. The requirement of transparent electrodes is estimated for displays based on electrowetting machanism, and nanotube films indicate promise for such a type of devices.

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PACS 72.80. Tm, 73.25+ i, 78.66.Sq, 78.67.Ch Flexible, transparent and conducting poly(methyl methacrylate) (PMMA) composites films were prepared using SOCl 2 functionalized SWNTs. Optical absorption spectra measured on composite films confirm that the composite preparation procedure preserves the electronic properties (position of the Fermi level) of the p-doped nanotubes in the polymer matrix. Due to the doping effect of SOCl 2 the electrical conductivity of the composites is improved by a factor of 5. The light transmission of the composite films depends on the film thickness and on the nanotube concentration. The optical transmittance of visible light at 500 nm was found to be 92% for 0.1 wt% SWNT loading and 46% for 0.5 wt% SWNT loading. The thickness of the specimens was approximately 20 µm. Conductivity measurement of the thin films performed with the four lead method revealed values 3.5 × 10 -3 S/cm and 4.7 × 10 -1 S/cm, respectively.