Electrical Properties of Well-Dispersed Nanopolyaniline/Epoxy Hybrids Prepared Using an Absorption-Transferring Process

Abstract

Novel polyaniline (PANI)/epoxy hybrids have been fabricated using an absorption-transferring process in which no organic solvent is involved. An epoxy prepolymer cured by aniline monomer (DGEBA-aniline) was added to a freshly prepared PANI nanoparticles (NPs) aqueous solution with vigorous agitation and heating (ca. 90 °C). The PANI NPs were absorbed on the surface of epoxy droplet and then transferred into the whole droplet. The microstructures of the product PANI/epoxy hybrids, characterized using scanning electron microscopy, featured well-dispersed PANI NPs (ca. 40∼60 nm) within epoxy matrixes; no large aggregates were observed. The hybrids exhibited huge negative permittivities; the electromagnetic interference shielding efficiency in an electric field at low frequency (100-1000 MHz) was ca. 30-60 dB. The welldispersed PANI NPs not only provided a continuous conducting network but also a higher level of charge delocalization.

Polyaniline nano-composites with large negative dielectric permittivity

“…Polyaniline has emerged as one of the most promising conducting organic polymers, owing to its high polymerization yield, good environmental stability, moderate electrical conductivity and relatively low production cost. Recently, we have worked on developing high dielectric permittivity nano-composites systems, such as PANI-DBSA/PU(polyurethane), 29 PANI-DBSA/ PAA, 30 and PANI-DBSA/epoxy, 31 for the applications in the fields of energy storage, integral capacitor technology, electro-active devices and electromagnetic interference(EMI). In these studies, negative ε values have been observed when we follow certain synthetic routes and fabrication procedures.…”

“…30,31 Figure 2 depicts the variation of ε of PANA-DBSA/PAA nano-composites, plotted with respected to PANI contents and the AC frequencies applied. The results show that a negative ε was obtained for all the nano-composites containing more than 6 wt% of PANI.…”

Single Negative Metamaterials in Unstructured Polymer Nanocomposites Toward Selectable and Controllable Negative Permittivity

“…[11,12,16,17] Moreover, their negative permittivity and/or negative permeability were considered to be caused solely by those inorganic inclusions, and were independent of the polymer properties. In a recent study, on nanopolyanilne/ epoxy hybrids obtained by a special absorption-transferring process, [18] the occurrence of negative permittivity was considered to have resulted from the formation of a continuous conductive network of conductive polymer, polyaniline.Our latest studies of polymer nanocomposites prepared in our facilities surprisingly showed negative permittivity values. It has been discovered that the negative permittivity can be obtained from lab-fabricated non-metallic nanocomposites by a conventional solution-processing method, without any specially designed structures within the nanocomposites.…”

“…This indicates that the conductivity of PEI/CNF nanocomposites can be considered to be unrelated to the negative permittivity, which is inconsistent with the results of the nanopolyaniline/epoxy hybrids. [18] According to the microstructures of the film samples of both PEI nanocomposites (Fig. 2), the changes of structures and Figure 1.…”

Enhancement of Electrical and Mechanical Properties of SU-8 Photocrosslinked Coatings Containing Polypyrrole-graphene Oxide Nanoparticles

“…All the SU-8/PPy-GOs nanocomposites show higher ε΄ and ε΄΄ than pure SU-8 and the values of both permittivities increase with increasing the loading of the PPy-GO nanofillers. The enhanced permittivity was widely observed in the nanocomposites and was attributed to the interfacial polarization in which the charge carriers were blocked at the internal surface or at interfaces between the matrix and the fillers leading to an increased permittivity [24,25]. In the SU-8/PPy-GOs, although the protons (hydrogen ions) provided by the doping acid can move along the PPy chains, these charge movements will be hindered by SU-8 resin, thus, a large number of space charges will accumulate at the interface of PPy and SU-8 and result in a larger interfacial polarization.…”