3 × 105 S/cm) and the creation of new electrical contacts by nanowires. In the case of AgNWs alone, the AgNW/PVDF composites show no

percolation up to 2 vol % filler loading. By adding small amounts of TRGs (0.04 and 0.08 vol %), the hybrids display a steady increase in conductivity with increasing Ag content. Interestingly, the conductivity of AgNW/TRG/PVDF hybrids is much higher than the total Cyclosporin A conductivity of both TRG/PVDF and AgNW/PVDF composites. Thus, there exists a synergetic effect between these two types of nanofillers [42]. It seems that AgNWs can CP-868596 in vivo bridge the TRG sheets effectively, facilitating the transport of electrons among them [43]. The presence of conducting network can be detected by the alternating current (AC) response that manifested itself in a

conductivity plateau. Figure  3b shows the AC conductivity of PVDF filled with TRGs, AgNWs, and hybrid nanofillers. For the TRG/PVDF and AgNW/PVDF composites, electrical conductivity rises almost linearly with the frequency, NSC 683864 chemical structure implying these materials are insulators. In contrast, the conductivity of AgNW/TRG/PVDF composite is frequency independent from 102 to 107 Hz. This sample exhibits a DC conductivity plateau over a broad frequency range, showing the formation of good conducting network. Figure  3c is a schematic diagram illustrating the occurrence of synergistic effect between the AgNW and TRG fillers in a conductive network. On the contrary, the AgNW or TRG filler alone does not form a conducting path. The percolated AgNW/TRG/PVDF composite exhibits higher conductivity compared to a combined total conductivity of TRG/PVDF and AgNW/PVDF composites. From Figure  3a, the conductivity of 1 vol % AgNW/0.04 vol % TRG/PVDF hybrid is more than nine orders of magnitude higher than that of the 1 vol % AgNW/PVDF composite. Furthermore, the conductivity

of 2 vol % AgNW/0.08 vol % TRG/PVDF, i.e., 10 S/cm is comparable to that of measured graphite paper with a conductivity of 12 S/cm [44]. Figure  4a,b is the SEM micrographs showing typical morphologies of hybrid composites. The AgNWs are well dispersed within the polymer matrix. The use of sonication during the composite Suplatast tosilate fabrication process can reduce the aspect ratio of AgNWs as expected.The effect of temperature (40 to 180°C) on electrical resistivity (a reciprocal of conductivity) of AgNW/TRG/PVDF hybrids is now discussed (Figure  5). All hybrid composites show a slow increase in resistivity with increasing temperature initially followed by a sharp increase in resistivity as the temperature approaches melting point of PVDF. This behavior is commonly referred to as the positive temperature coefficient (PTC) effect of resistivity. A maximum increase in resistivity is particularly apparent for the composite with 0.04 vol % TRG and 1 vol % AgNW loadings, being more than four orders of magnitude higher than that at 40°C. Above the melting temperature of PVDF, a reverse effect, i.e.