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The aim of this study was to improve the electrical resistivity, mechanical properties, and interfacial properties between the carbon fiber (CF) and cellulose of conductive paper containing 10% CF so as to better meet the demands for electric heating wood floors. With waterborne polyurethane (WPU) treatment and nitrogen plasma modification methods, the interfacial properties between CF and cellulose were improved dramatically. Fourier transform infrared spectrometry (FTIR) revealed that the plasma modification method reduced the C-H contents and introduced numerous polar groups onto the CF surface. Scanning electron microscopy (SEM) showed that the CF modified by WPU and plasma had good adhesion with cellulose. The tensile index, tensile energy absorption index, and burst index of the paper were enhanced because of the plasma and WPU coating. The carbon fiber and WPU method presented good synergistic action with respect to mechanical properties and electrical resistivity, and the lowest electrical resistivity of conductive paper was reduced from 0.68 •cm2 to 0.44 •cm2.

Carbon fiber paper (CFP), a material frequently used as the diffusion layer in fuel cells, was found recently to exhibit a potential as an electrode for the development of sensitive, unmediated biosensors. After nitrogen plasma treatment, the CFP exhibited a quasi-reversible behavior to the redox couple (e.g., ferricyanide) with an electron transfer rate constant of 7.2 × 10(-3)cms(-1). This rate constant is approximately double that of a Pt-electrode and is much higher than that of many carbon-based electrodes. The unmediated CFP-based tyrosinase biosensor fabricated for this study exhibited an optimal working potential and operating pH value of -0.2V and 6.5, respectively. Compared to other unmediated tyrosinase biosensors, the CFP-based tyrosinase biosensor offers a high sensitivity for the monitoring of phenolic compounds (17.8, 7.1, 5.2 and 3.7 μA μM(-1)cm(-2) for catechol, phenol, bisphenol and 3-aminophenol, respectively). The lowest detection limit for catechol, phenol, bisphenol and 3-aminophenol was 2, 5, 5 and 12 nM, respectively. Furthermore, this biosensor exhibited a good repeatability, a fast response time (around 10s), and a wide linear dynamic range of detection for phenolic compounds.