Synthesis of Conductive Nanofillers/Nanofibers and Electrical Properties of their Conductive Polymer Composites
| atmire.migration.oldid | 2260 | |
| dc.contributor.advisor | Sundararaj, Uttandaraman | |
| dc.contributor.author | Sarvi, Ali | |
| dc.date.accessioned | 2014-07-02T20:55:21Z | |
| dc.date.available | 2014-11-17T08:00:36Z | |
| dc.date.issued | 2014-07-02 | |
| dc.date.submitted | 2014 | en |
| dc.description.abstract | Thanks to their corrosion resistance, light weight, low cost, and ease of processing, electrically conducting polymer composites (CPCs) have received significant attention for the replacement of metals and inorganic materials for sensors, actuators, supercapacitors, and electromagnetic interference (EMI) shields. In this PhD thesis, high aspect ratio conductive nanofillers namely copper nanowires (CuNWs) and multiwall carbon nanotubes (MWCNTs) were coated with polyaniline (PANi) using solution mixing and in-situ polymerization method, respectively. Transmission electron microscopy (TEM) showed a smooth polyaniline nano-coating between 5-18 nm in thickness on the nanofillers’ surface. The coating thickness and; consequently, electrical conductivity was controlled and tuned by polyaniline/aniline concentration in solution. Composites with tunable conductivity may be used as chemisensors, electronic pressure sensors and switches. Coated nanofillers demonstrated better dispersion in polystyrene (PS) and provided lower electrical percolation threshold. Dispersion of nanofillers in PS was investigated using rheological measurements and confirmed with electron micrographs and nano-scale images of CPCs. Polyaniline (PANi), when used as a coating layer, was able to attenuate electromagnetic (EM) waves via absorption and store electrical charges though pseudocapacitance mechanism. The dielectric measurements of MWCNT-PANi/PS composites showed one order of magnitude increase in real electrical permittivity compared to that of MWCNT/PS composites making them suitable for charge storage purposes. Incorporation of PANi also brought a new insight into conductive network formation mechanism in electrospun mats where the orientation of conductive high aspect ratio nanofillers is a major problem. Conductive nanofibers of poly(vinylidene fluoride) (PVDF) filled with coated multiwall carbon nanotubes (MWCNTs) were fabricated using electrospinning. These highly oriented PVDF nanofibers exhibited high beta (β) crystal content and enhanced piezoelectricity. Moreover, multilayer electrospun nanofibers, in which MWCNTs were located at the shell layer, were fabricated for further decrease in electrical percolation threshold. In addition to the PANi coated nanofillers, immiscible polymer blends (poly(methyl methacrylate) (PMMA) and styrene-acrylonitrile copolymer (SAN) blends) were employed to deliver lower percolation threshold via double percolation phenomenon. Conductivity measurements revealed a significant decrease in electrical percolation threshold (0.4 wt%) for PMMA70/SAN30 blends compared with MWCNT-filled SAN and PMMA (ca 0.8 wt%). | en_US |
| dc.identifier.citation | Sarvi, A. (2014). Synthesis of Conductive Nanofillers/Nanofibers and Electrical Properties of their Conductive Polymer Composites (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/27957 | en_US |
| dc.identifier.doi | http://dx.doi.org/10.11575/PRISM/27957 | |
| dc.identifier.uri | http://hdl.handle.net/11023/1595 | |
| dc.language.iso | eng | |
| dc.publisher.faculty | Graduate Studies | |
| dc.publisher.institution | University of Calgary | en |
| dc.publisher.place | Calgary | en |
| dc.rights | University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission. | |
| dc.subject | Materials Science | |
| dc.subject.classification | Conductive Polymer Composites | en_US |
| dc.subject.classification | Electrical Conductivity | en_US |
| dc.subject.classification | Nanofiber | en_US |
| dc.subject.classification | Nanowire | en_US |
| dc.subject.classification | EMI Sheilding | en_US |
| dc.title | Synthesis of Conductive Nanofillers/Nanofibers and Electrical Properties of their Conductive Polymer Composites | |
| dc.type | doctoral thesis | |
| thesis.degree.discipline | Chemical and Petroleum Engineering | |
| thesis.degree.grantor | University of Calgary | |
| thesis.degree.name | Doctor of Philosophy (PhD) | |
| ucalgary.item.requestcopy | true |