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The combination of copper and dielectric materials have emerged as one of the most promising alternatives for the next generation of charge storage devices and microelectronic integrated circuits. In this work, copper nanowires (CuNW) were synthesized using a hard template technique, where copper was electrodeposited into and then liberated from porous alumina templates. Flexible nanofibers of poly(vinylidene fluoride)/copper nanowire (PVDF/CuNW) at different loadings were then obtained using the technique of electrospinning. SEM and TEM images showed that the CuNW had a straight, rigid structure with an average length and diameter of 1.5 µm and 30 nm, respectively. The morphological characterizations also revealed that the CuNW were embedded and aligned inside the nanofibers of PVDF, leading to an increase in the diameters of the generated electrospun nanofibers, e.g., 154 nm and 227 nm for pure PVDF and PVDF/CuNW (20 wt%), respectively. The polymorphic behavior of the PVDF/CuNW nanofibers was studied by FTIR and WAXD, confirming the positive impact of electrospinning on piezoelectric β phase formation of the PVDF matrix. Dielectric measurements indicated that the real permittivity of the mats of the nanofibers increased with CuNW loading. The ascending trend of the real permittivity with the filler content was ascribed to the formation of nanocapacitor structures, i.e., the copper conductive nanofillers acting as nanoelectrodes and the polymer matrix as nanodielectrics. Thus, the results of this study showed that the electrospun PVDF/CuNW nanofibers could be suitable in applications where flexible dielectric and piezoelectric materials are required.

Electrical conductive nanostructures made of nanofibers of poly (amide 6) (PA6) with carboxyl functionalized multiwall carbon nanotubes (MWCNTCOOH) and anchored MWCNTCOOH were produced. The nanotubes were surface activated with carboxyl groups, dispersed in formic acid and added to a formic acid solution of PA6. The mixture was electrospun by applying a voltage of 30 kV; afterwards, the nanofiber's mats were immersed in an aqueous dispersion of MWCNTCOOH containing a nonionic surfactant. The chemical structure, morphology, thermal stability, and electrical conductivity of the nanostructures were evaluated by UV spectroscopy, scanning (SEM), and transmission electron microscopy (TEM), thermal gravimetric analyses (TGA) and volumetric conductivity measurements. The efficiency of the functionalization was confirmed by the UV peaks in the range between 220 and 250 nm (corresponding to a carbonyl group conjugated with a carbon-carbon double bond). SEM and TEM micrographs showed the pullout of the MWCNTCOOH from the nanofibers and the formation of a stable, percolated, and anchored MWCNTCOOH network on the nanofibers due to the anchoring of the MWCNTCOOH from the surfactant solution on the MWCNTCOOH of the nanofibers. The coated nanostructures had higher thermal stability and higher electrical conductivity than the noncoated ones, showing the efficiency of this simple procedure. POLYM. ENG. SCI., 55:1263–1272, 2015. © 2015 Society of Plastics Engineers

In this work,polymer nanocomposites of polystyrene-b-polybutadiene-b-polystyrene (SBS), atriblock copolymer, and multi-walled carbon nanotubes (MWCNTs)wereproduced by melt mixing. MWCNTs contents between 0 and 10% (v/v) were used to produce the SBS/MWCNTs nanocomposites. Electrical conductivity of these materials was measured and compared with polystyrene (PS)/MWCNTs nanocomposites with the same MWCNTs loadings. The results showed that electrical percolation thresholdofSBS/MWCNTs was 0.9% (v/v) and 3.5% for PS/MWCNTs. The rheological percolation thresholdat temperature of the processing 150°C, was also reduced from 3.5% for PS to 1.1% for SBS. These results suggested that SBS copolymer matrixhad a better affinity with MWCNTs, which was confirmed by transmition electron microscopyimages (TEM), whichshowed a better dispersion of the MWCNTs in SBS than in PS matrix.

© 2015 AIP Publishing LLC.The search for new biomaterials in the bone reconstitution field is growing continuously as humane life expectation and bone fractures increase. For this purpose, composite materials with biodegradable polymers and hydroxyapatite (HA) have been used. A composite material formed by a film, nanofibers and HA has been made. Both, the films and the non-woven mats of nanofibers were formed by nanocomposites made of butylene adipate-co-terephthalate (PBAT) and HA. The techniques used to produce the films and nanofibers were spin coating and electrospinning, respectively. The composite production and morphology were evaluated. The composite showed an adequate morphology and fibers size to be used as scaffold for cell growth.

In this work, nanocomposites based on the triblock copolymer polystyrene-b-polyisoprene-b-polystyrene (SIS) thermoplastic elastomer filled with multiwall carbon nanotubes (MWCNT) were obtained by melt mixing. The nanocomposites were characterized by oscillatory rheometry, electrical resistivity, small angle x-ray scattering (SAXS) and transmission electron microscopy (TEM). The results showed that both, rheological and electrical percolation were achieved at MWCNT loadings between 1-3 vol.%. Rheological tests revealed that the insertion of MWCNT into SIS significantly enhanced the process of relaxation of SIS blocks. Resistivity measurements revealed that conductive nanocomposites were obtained at MWCNT loadings ~1.6 vol.%. The electrical resistivity decreased eleven orders of magnitude from neat SIS to SIS/ 5 vol.% MWCNT. Finally, SAXS and TEM showed that the melt mixing process and the presence of MWCNT hampered the self-assembly of SIS into well-ordered domains.