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The growing interest in the application of polypyrrole (PPy) for electrodes of electrochemical supercapacitors (ES) is attributed to the relatively high specific capacitance (SC), low cost, high electrical conductivity, advanced chemical and mechanical properties of PPy. However, it is found that swelling and shrinkage occurred during charge-discharge, resulting in higher impedance, gradual adhesion loss and poor cycling behavior of PPy electrode. Moreover, mass normalized capacitance decreased significantly with increasing electrode mass, especially at high charge-discharge rates. Therefore, it is challenging to achieve good electrochemical performance, cyclic stability and good capacitance retention at high charge-discharge rates for electrodes with mass loadings above 20 mg/cm2, which is required for many practical applications.To address this problem, PPy-MWCNT (multiwalled carbon nanotube) composites were prepared using polycharged aromatic anionic redox active molecules as dopants for PPy and dispersants for MWCNT. New dopants offer the advantages of their reduced movement during charge-discharge process and reduced PPy swelling because of large molecular size. In addition, polycharged dopants, containing several charged groups, can be linked to different polymer macromolecules, thus increasing interchain mobility of charge carriers and increasing PPy conductivity. Moreover, new dopants exhibit redox active properties and thus contribute to the total electrode capacitance. The reasons for adding MWCNTs are following: first, they can enhance charge storage properties of PPy by increasing the conductivity of composites, which is more obvious when the scan rate is high. Second, the network formed by MWCNTs can restrict the swelling of PPy and improve the cyclic stability.In this research, new promising PPy-MWCNT electrodes were fabricated. 7 different molecules were used as new dopants for chemical synthesis of PPy. The molecular size and functional groups of the anionic dopants and dispersants have great influence on the morphology and capacitive properties of PPy and PPy/MWCNT composites. Moreover, PPy-MWCNT-FeOOH composite was also prepared in order to shift the working voltage window of PPy/CNT composite to more negative direction, which can facilitate the utilization of PPy as negative electrode. The results showed that dopants with large size, multiple charges and high charge to mass ratio can decrease PPy particle size, reduce agglomeration and thus improve PPy capacitive properties. The highest SC of 118.26 F/g was achieved at 2 mV/s by using PMSS-SR31 doped PPy-MWCNT electrodes. The highest SC of 65.09 F/g at 100 mV/s was achieved by using Potassium Benzene-1,2-disofulnate doped PPy-MWCNT electrodes. Adding FeOOH to PPy-MWCNT composite with mass ration between PPy and FeOOH of 7/2 allowed for enhanced performance in a working voltage window of -0.8 - +0.1 V, which facilitated the utilization of PPy as a negative electrode in asymmetrical device. Thesis Master of Applied Science (MASc)

Electrochemical supercapacitors (ESs) have attracted great attention due to the advantages of long cycle life, high charge/discharge rate and high power density compared to batteries. Significant improvement in ES performance has been achieved via development of advanced nanostructured materials, such as MnO2 and composite MnO2-MWCNT and PPy-MWCNT electrodes. In this dissertation, advanced dispersants were developed and investigated for the dispersion, surface modification and electrophoretic deposition (EPD) of metal oxides, multiwalled carbon nanotubes (MWCNT) and polypyrrole (PPy) in different solvents. Nature-inspired strategies have been developed for the fabrication of MWCNT films and composites. The outstanding colloidal stability of MWCNT, dispersed using anionic bile acids, allowed the EPD of MWCNT. Composite MnO2-MWCNT films were obtained by anodic EPD on Ni plaque and Ni foam substrates. Good dispersion of MWCNT during Py polymerization was achieved and allowed the formation of PPy coated MWCNT. The film and bulk electrodes, prepared by EPD and slurry impregnation methods, respectively, showed high capacitance and good capacitance retention at high charge-discharge rates. The mechanisms of dispersion and deposition were investigated. Cathodic and anodic EPD of MWCNT, MnO2, Mn3O4 was achieved using positively and negatively charged dispersants. Co-deposition of MWCNT and MnO2 was performed using a co-dispersant, which dispersed both MWCNT and MnO2 in ethanol. Composite films were tested for ES applications. The efficient dispersion was achieved at relatively low dispersant concentrations due to strong adsorption of the dispersants on the particle surface, which involved the polydentate bonding. We found the possibility of efficient dispersion of MWCNT in ethanol using efficient anionic dispersants. The electrostatic assembly method has been developed, which offers the benefit of improved mixing of MnO2 and MWCNT. The use of different anionic and cationic dispersants allowed the fabrication of electrodes with enhanced capacitance and improved capacitance retention at high charge–discharge rates and high active mass loadings. The asymmetric devices, containing positive MnO2–MWCNT and negative AC–CB electrodes showed promising performance in a voltage window of 1.6 V. We proposed another novel concept based on electrostatic heterocoagulation of Mn3O4- MWCNT composites in aqueous environment. In this case, various dispersants were selected for adsorption and dispersion of MWCNT and Mn3O4 and this allowed the formation of stable aqueous suspensions of positively charged MWCNT and negatively charged Mn3O4, which facilitated the formation of advanced composites with improved mixing of the components. Testing results showed promising performance of Mn3O4–MWCNT composites for applications in electrodes of electrochemical supercapacitors. Thesis Doctor of Philosophy (PhD)

Electrochemical Supercapacitors (ESs) have been under investigation for decades as advanced energy storage devices. Selection and fabrication of electrode materials are of vital importance for ESs in terms of energy density, power density, cycling stability, specific capacitance, impedance and other capacitive properties. Among various kinds of materials that can be used for electrode fabrication for ES, Polypyrrole (PPy) is found to be promising due to high specific capacitance, high electric conductivity and low cost of fabrication of this material. The addition of advanced anionic dopant enables higher electric conductivity and the combination of PPy and multiwalled carbon nanotubes (MWCNT) enhances cycling stability of polymer backbone during testing process, which improves capacitive behavior of PPy and the composite materials. Since MWCNT has a relatively high aspect ratio making it difficult to be well dispersed, the selection of effective dispersing agents and dispersion of MWCNT consist an important part of this research. In this research, PPy and PPy/MWCNT composite materials were synthesized both in chemical and electrochemical ways. The anionic dopants included 4, 5-Dihydroxy-1, 3-benzenedisulfonic acid disodium salt monohydrate (Tiron) and 4-Formylbenzene-1, i M.A.Sc Thesis Jieming Li McMaster University Materials Science and Engineering 3-disulfonic acid disodium salt hydrate (FDS). And also three kinds of multifunctional dopants were used, that can act as dopant for PPy and dispersing agent for MWCNT at the same time, including Eriochrome Cyanine R (ECR), 4-Amino-5-hydroxy-2, 7-naphthalenedisulfonic acid monosodium salt hydrate (AHN) and 3-Hydroxy-4-nitroso-2, 7-naphthalenedisulfonic acid disodium salt (HNN). The molecular size and functional groups of the anionic dopants and dispersants have great influence on the morphology and capacitive properties of PPy and PPy/MWCNT composites. Higher specific capacitance and excellent capacitance retention were achieved by chemical synthesis, which also offers advantages for large scale production. The results showed that with dopants possessing larger molecular size and multiple charged groups, smaller particle size of PPy and improved capacitive properties could be obtained. The PPy/MWCNT mass ratio of 7 to 3 and Py monomer to dopant molecule molar ratio of 3 to 1 were found to be optimal. The use of Ni foam current collector enabled high mass loading of active materials, which facilitates the fabrication of advanced electrodes for supercapacitors. Thesis Master of Applied Science (MASc)

With a unique blend of power and energy densities, as well as long cycling lives, electrochemical supercapacitors are finding greater application in energy storage solutions. Among candidate materials for supercapacitors, MnO2 has garnered a great deal of attention. However, its low intrinsic electrical conductivity has proven to be a serious hindrance on performance when used in supercapacitor electrodes. Efficient use of conductive additives is a demonstrated, effective method to combat this problem, however there is still a great need for improvement. Two new colloidal processing techniques have been developed to mix chemically synthesized MnO2 and conductive multi-walled carbon nanotubes (MWCNT). The first strategy involved the linking of MnO2 and MWCNT through the formation of a Schiff base. 3,4-dihydroxybenzaldehyde (DB) was used to modify MnO2, while MWCNT were dispersed with the dye New Fuchsin (NF). These compounds were selected due to the presence of molecular features previously identified as conducive to strong adsorption and good colloidal dispersion, as well as the necessary functional groups required to form a Schiff base. The second involved the use of liquid-liquid extraction, primarily in an attempt to prevent post synthesis MnO2 particle agglomeration. Lauryl gallate (LG) was used as an extracting and dispersing agent for MnO2 synthesized via the reaction between aqueous potassium permanganate (KMnO4) and 1-butanol. LG facilitated the co-dispersion and mixing of both MnO2 and MWCNT in the 1-butanol phase. V2O3 was also investigated as a replacement for MnO2, as its high intrinsic electrical conductivity gives it a potential advantage over MnO2. In each of these three projects, electrodes were produced with exceptionally high areal normalized capacitances at high active mass loadings. The MnO2-MWCNT composites were used to fabricate full asymmetric supercapacitor devices that were able to deliver a useable amount of energy. Thesis Master of Applied Science (MASc) The modern world has an insatiable appetite for energy and must have access to it for stationary and mobile applications. To meet this demand, it is of paramount importance to develop new, high performance energy storage technologies. The energy requirements for different applications, however, necessitate storage devices that have suitable properties. The energy stored in a large pool of hot water is not in a suitable form to power a cellphone. The key goal of this work was to further develop one particular energy storage technology, called electrochemical supercapacitors. Novel processing techniques were developed and new materials investigated with the aim of producing supercapacitor electrodes that would exceed the performance of what is already available today. The materials that were produced exhibited very high performance and offered new insight and direction for further research in this exciting field.

Novel electrocchemical and chemical strategies have been developed for the fabrication of functional nanocomposites. New scientific and engineering contribution of this work to colloidal nanotechnology included the development of advanced chelating dispersing agents, such as various small organic molecules and chelating polymers. The unique feature of such dispersion agents is their strong adsorption on the surface of different materials, which allows superior dispersion. The chelating monomers of chelating polymers, such as PAZO and PMSS provided multiple adsorption sites for bonding to metal atoms on the particles surface. We analyzed and developed new fundamental adsorption and dispersion mechanisms. An important finding was the possibility of co-dispersion and co-deposition of advanced materials such as oxides, nitrides, complex oxides and minerals using universal dispersing agents and formation of composites by EPD method. It was found that Caffeic acid (CA) can be used as an efficient dispersing agent for the synthesis of ZnO nanorods of reduced size and a dispersing agent for the EPD of ZnO films. Another important achievement of this work was the application of tannic acid as an efficient capping and dispersing agent for synthesis and EPD of inorganic materials and composites. An important discovery was the use of lauryl gallate dispersant as a reducing agent for the synthesis of AgNp and a vehicle for particle dispersion and extraction in the liquid-liquid extraction method. Further advancements in our new technologies allowed us to develop composite films using anodic EPD using weak polyelectrolytes, such as alginate. The composite coatings exhibited protective and flame retardant properties. We analyzed the deposition mechanisms and kinetics as well as microstructure of the coatings. In another strategy, we developed electrochemical strategies for the deposition of composites, based on strong polyelectrolytes. The approach is based on the EPD of the polyelectrolyte molecules and electrosynthesis of EPD of ceramic particles. The electrostatic heterocoagulation mechanism was proposed for the deposit formation. We investigated the deposition kinetics, composition and microstructure of the composites prepared by the new strategies. The new electrochemical strategies can be used for the deposition of other composites, based on functional polymers with pH independent charge. New methods have been developed for the chemical synthesis of PPy based composites, using PMSS, PMSS–SR11 and PMSS–SR31 as anionic dopants for chemical polymerization and dispersants for MWCNT. The composites showed promising performance for application in electrodes of electrochemical supercapacitors. Good electrochemical performance was achieved at high active mass loadings. The electrodes showed high capacitance, large voltage window and low impedance. The analysis of electrochemical testing results and chemical structure of PMSS, PMSS–SR11 and PMSS–SR31 provided an insight into the influence of the anionic functional groups on the capacitance and capacitance retention a high charge-discharge rates. Thesis Master of Applied Science (MASc)

In this study, polypyrrole (PPy) prepared by chemical and electrochemical polymerization was investigated as the electrode of electrochemical supercapacitor (ES). New strategies were developed for the fabrication of nano-structured PPy and PPy based nano-composites, which included discovery of advanced anionic dopants and multi-functional nano-crystals, and development of co-dispersing agents. These methods improved the capacitive performance and cycle stability of PPy electrodes. The results indicated that high material loading and good capacitance retention of PPy was achieved using an electrochemical polymerization method and Ni plaque as the current collectors. Nano-crystalline (CTA)2S2O8 formed by a chemical precipitation method from solutions, containing anionic oxidant (S2O82-) and cationic surfactant (CTA+), could be used as the oxidant to synthesize PPy nano-fibers. We demonstrated that multi-wall carbon nanotubes (MWCNT) can be efficiently dispersed using such nano-crystals. Application of multi-functional nano-crystals is a conceptually new approach for the fabrication PPy coated MWCNT. Moreover, safranin and malachite green were found as universal dispersing and charging agents for cataphoretic deposition of graphene, MWCNT and PPy nano-fibers. It opens new strategies in colloidal and electrochemical processing of PPy nano-composites for ES electrodes. PPy coated MWCNT, prepared by the multi-functional nano-crystals (CTA)2S2O8, was employed for the fabrication of N-doped activated carbon-coated MWCNT (N-AC-MWCNT). The obtained N-AC-MWCNT was uniformly coated and possessed with high surface area. The use of N-AC-MWCNT enabled the fabrication of ES electrodes with high mass loading and high active material to current collector mass ratio. Symmetric and asymmetric ES cells, fabricated by N-AC-MWCNT and aqueous Na2SO4 electrolyte, showed high specific capacitance, good capacitance retention and large voltage window. The positive electrode of asymmetric ES, MnO2 coated MWCNT, was successfully prepared by the chemical reaction between KMnO4 and N-AC-MWCNT. The problem of degradation of MWCNT was avoided by the use of N-AC as the sacrificial carbon. Significant progress on ES technology has allowed for the development of capacitive dyes removal (CDR) methods using ES devices. In our study, porous carbon materials, N-doped activated carbon coated MWCNT (N-AC-MWCNT) and N-doped activated carbon nano-fibers (N-AC-NF), were developed as the electrodes for CDR applications. The experimental results indicated that capacitive performance of ES cells was influenced by the chemical structure, size, charge-to mass ratio, concentration and redox-active ligands of the dyes. CDR is a promising method for removal of various cationic and anionic dyes, which offers advantages of energy saving and simple electrode regeneration. Thesis Doctor of Philosophy (PhD)

Electrochemical supercapacitors (ECs) attract significant attentions for their unique characteristics of high power density, good cycling capability and low cost. This dissertation will focus on fabrication of composite materials for electrodes and devices of ECs. A conceptually new colloidal approach to the fabrication of metal oxide – multiwalled carbon nanotube (MWCNT) composites is proposed. The heterocoagulation of positively charged oxide nanoparticles and negatively charged MWCNT allows the fabrication of advanced nanocomposites with improved dispersion of individual components. The proof-of-principle was demonstrated by the fabrication of MnO2-MWCNT electrodes for ECs with excellent performance. We proposed another novel concept based on electrostatic heterocoagulation of MnO2-MWCNT composites in aqueous environment. In this case, Benzyldimethylhexadecylammonium chloride (BAC) surfactant and caffeic acid (CA) were selected for adsorption and dispersion of MWCNT and MnO2, respectively, and this allowed the formation of stable aqueous suspensions of positively charged MWCNT and negatively charged MnO2. The asymmetric device showed high capacitance, high powerenergy characteristics with enlarged voltage window of 1.8 V, good capacitance retention at high charge-discharge rates and cyclic stability. A novel capacitive material BiMn2O5 was firstly discovered and synthesized for ECs applications in our studies. The BiMn2O5 nanocrystals were prepared by a hydrothermal method. We demonstrated for the first time that BiMn2O5 – MWCNT composite can be used as a new active material for positive electrodes of ECs. The composite electrode with high mass loading showed a capacitance of 6.0 F cm-2 (540 F cm-3) at a scan rate of 2 mV s-1 and excellent capacitive behavior at high scan rates. As-fabricated device showed good cyclic stability in a voltage window of 1.8 V with energy density of 13.0 Wh L-1 (9.0 Wh kg-1) and power density of 3.6 kW L-1 (2.5 kW kg-1). We firstly discovered that Poly[1-[4-(3-carboxy-4 hydroxyphenylazo)benzenesulfonamido]- 1,2-ethanediyl, sodium salt] (PAZO) can be used as an universal dispersant for various materials and its thin film fabricated by electrophoretic deposition (EPD) exhibited photo-induced birefringence. Our new findings indicated that PAZO is good candidate for diverse materials dispersing because it contains diaromatic monomers with salicylate ligands, which can provide multiple adsorption sites for efficient adsorption on particles and impart electrical charges to the particles. Additionally, the use of PAZO polymer offers the advantages of improved steric stabilization. We discovered that Celestine blue (CB) can be developed as an efficient dispersing agent for the nanoparticles. We found that CB includes a catechol ligand, which can provide CB adsorption on inorganic nanoparticles. The relatively large size of the CB molecules is beneficial for the electrosteric dispersion. The benefits of cathodic EPD for nanotechnology were demonstrated by the formation of nanostructured MnO2 films on commercial high surface area current collectors for energy storage in ECs. Thesis Doctor of Philosophy (PhD)

Investigation of flame retardant materials (FRM) identified materials as effective substitutes for halogenated FRM. Many promising materials were tested such as hydrotalcite-type Al–Mg–Zr complex hydroxide, huntite, aluminum hydroxide, hydrotalcite, magnesium carbonate hydroxide pentahydrate, magnesium sulfate heptahydrate, magnesium phosphate hydrate, magnesium chloride hexahydrate, sodium metasilicate pentahydrate, XZO 2022 (Mg3Al) and halloysite. Electrophoretic deposition (EPD) manufacturing technique has been developed for the fabrication of coatings containing the most promising FRM candidates. Identifying charging and dispersion agents, such as poly(4-vinylpyridine-co-butyl methacrylate), humic acid, 2,2′- biquinoline-4,4′-dicarboxylic acid, quaternized hydroxyethylcellulose ethoxylate, 3- phosphonopropionic acid, 16-phosphonohexadecanoic acid, octadecylphosphonic acid, celestine blue, chitosan, to facilitate EPD was of great importance for successful deposition of composite FRM films. The films were investigated using scanning electron microscopy, transmission electron microscopy, X-ray diffraction analysis, thermogravimetric and differential thermal analysis, as well as Fourier Transform Infrared and Ultraviolet-Visible spectroscopy. Thesis Master of Science (MSc) Technology is expanding, as is our understanding of the environmental and health impacts of chemicals. New flame retardant materials (FRM) must be developed to help protect against fire hazards in increasingly complex products, but care must be taken to avoid implementing dangerous chemicals. This work identifies new FRM which can be efficient replacements for widely used, but toxic FRM. FRM can be applied as a coating cheaply, quickly, and evenly onto substrates of even a complex shape. Techniques and additive chemicals are suggested to create advanced FRM coatings

Colloidal processing has been widely used for many industrial application. Electrophoretic deposition (EPD) is an important colloidal technique, which plays an important role in the fabrication of organic-inorganic composites. In this work, advanced dispersing agents with excellent adsorption, dispersion and film forming properties have been developed. The adsorption mechanism and the deposition kinetics of EPD have been studied. It is shown that catechol and salicylic groups of dispersants can form chelation bonding with metal atoms on inorganic particle surface and provide particle charging, dispersion and deposition. The aromatic dispersants can adsorb on carbon nanotubes due to π-π interactions. The long chain ionic polymeric dispersants were investigated, which provide efficient electrosteric stabilization. The film forming properties of dispersants allow dispersants with dispersed materials to deposit and form composite films on the substrate. Universal dispersing agents have been developed for the colloidal processing. These dispersants show possibilities to adsorb and disperse various organic and inorganic materials and pave the way for the fabrication of multi-functional materials for various applications. The composite materials, prepared using new dispersants showed promising corrosion protection of metals, flame retardant and energy storage properties. Thesis Master of Applied Science (MASc)

In this research, different anionic dopants were investigated for the fabrication of polypyrrole (PPy) electrode materials for electrochemical capacitors (ECs). Anionic dopants from catechol, salicylic acid and chromotropic acid family allowed for the formation of adherent PPy thin film on stainless steels current collectors by electropolymerization. Comparison between galvanostatic and pulse electropolymerization of PPy thin films was made. Pulse electropolymerization was found to provide improved impregnation of Ni plaque current collectors and formation of nanostructured coating. The electrodes prepared by pulse electropolymerization showed higher porosity, lower electrical resistance, higher capacitance and improved cyclic stability. In order to overcome the mass loading limitation for thin film PPy electrodes, chemical polymerization of PPy was investigated. The use of fine particles, prepared by the chemical polymerization method, allows impregnation of Ni foams and fabrication of porous electrodes with high materials loading. Moreover, improved capacitive performance and cyclic stability was obtained for PPy electrodes with high materials loading using new anionic dopants. To further improve the cyclic stability of PPy electrodes, multiwalled carbon nanotubes (MWCNT) were used for the fabrication of PPy-MWCNT composite materials due to their high surface area and excellent conductivity. Different dispersants as well as dispersing methods were studied in order to obtain stable MWCNT suspensions. Among those dispersants, multifunctional anionic dopants were found to benefit the formation of MWCNT suspension as well as the polymerization of PPy. A conceptually new approach has been developed for the fabrication of PPy coated MWCNT based on the use of multifunctional anionic dopants. The use of PPy coated MWCNT allowed excellent electrochemical performance for high active mass loadings, required for commercial EC applications. The electrodes and devices made of PPy coated MWCNT showed high capacitance, good capacitance retention at high charge-discharge rates and good cycling stability. The record high capacitance achieved at high charge-discharge rates is promising for the development of high power ECs. Thesis Doctor of Philosophy (PhD)

Advanced dispersants were discovered for the fabrication of homogeneous suspensions of multi-walled carbon nanotubes (MWCNT), graphene, and manganese dioxide (MnO2) in both ethanol and water. Thin films of MWCNT, graphene, MnO2, composite films of MWCNT-MnO2 and MWCNT-graphene were prepared using electrophoretic deposition (EPD) and electrolytic deposition (ELD) methods. The mechanisms of dispersion and deposition were investigated. Cathodic EPD was achieved for MWCNT and graphene using positively charged dispersants. Co-deposition of MWCNT and MnO¬2 was performed using a co-dispersant, which dispersed both MWCNT and MnO2 in ethanol. Composite films were tested for electrochemical supercapacitor (ES) purposes. Pulse ELD was used to deposit porous MnO2 coatings on Ni foam substrates from KMnO4 solutions. Cathodic deposition offered advantages, compared to anodic deposition, because the problems, related to anodic dissolution of metallic substrates, can be avoided. The pulse ON/OFF times had significant influence on the morphology and structure of MnO2 films, which further determined the capacitive performance. The influence of MnO2 film thickness on specific capacitance was investigated. Porous and conductive vanadium nitride (VN) was synthesized using melamine as a reducing agent. To further improve film conductivity and specific surface area, MWCNT were incorporated into VN matrix during synthesis. VN-MWCNT composite electrodes and VN-MWCNT/MnO2-MWCNT asymmetric supercapacitor cells were fabricated and tested. The electrodes and cells exhibited excellent electrochemical capacitive performance with good cyclic stability. The asymmetric supercapacitor device showed a voltage window up to 1.8 V, which was the combination of voltage window of VN-MWCNT (-0.9 V--0 V) and MnO2-MWCNT (0 V--0.9 V). Polypyrrole (PPy) coated MWCNT were synthesized in ethanol with ammonium peroxydisulfate solution as an oxidant. The effects of dopants to PPy morphology and conductivity was investigated. Dopants with electrochemical active groups were selected for the synthesis of PPy nanoparticles, where dopants also contributed to the capacitance of the polymer based materials. Both PPy-MWCNT/PPY-MWCNT symmetric supercapacitors and VN-MWCNT/PPY-MWCNT asymmetric supercapacitors were fabricated and tested, where the voltage windows were 0.9 V for the former and 1.3 V for the later. The increase of voltage window was ascribed to the asymmetric structure and negative voltage window of VN-MWCNT composite. Thesis Doctor of Philosophy (PhD)

Electrochemical Supercapacitors (ES), also known as Supercapacitor or Ultracapacitor, has been regarded as an advanced electrical energy storage device for decades. Fabrication of advanced electrode materials is of critical importance for advanced ES. Among various materials used for ES electrode, polypyrrole (PPy) is found to be a promising material due to high specific capacitance, good electrical conductivity, low cost and ease of processing. The use of advanced anionic dopants and addition of multiwall carbon nanotube (MWCNT) have been proved an .effective approach towards advanced PPy based ES with improved electrochemical behaviors. In this research, chemical polymerization of PPy powders and PPy/MWCNT composite materials have been successfully accomplished in presence of advanced anionic dopants, including chromotrope families, amaranth, pyrocatechol violet, eriochrome cyanine R and acid fuchsin. The influence of polyaromatic dopants with different molecular size, charges and charge to mass ratios on the microstructure and electrochemical characteristics has been discussed. PPy coated MWCNT with uniform microstructures was successfully achieved in simple chemical methods. The results showed PPy powders with enhanced microstructures and electrochemical behaviors can be obtained by using such advanced anionic dopants. Multi-charged polyaromatic dopants with larger molecular size benefitted PPy powders with smaller particle size, improved specific capacitance, and enhanced cycling stability, at high electrode mass loadings. Moreover, advanced aromatic dispersant and chemical synthesis was proved a simple and effective method for fabrication of PPy/MWCNT composite materials at different PPy/MWCNT mass ratio, among which the powder with PPy/MWCNT mass ratio of 7:3 showed optimum electrochemical performance. Last but not the least, the use of advanced high porosity current collector (Ni foam) allowed high electrode mass loading and good electric conductivity. As a result, advanced PPy/MWCNT composite materials which allows improved electrochemical behaviors, especially at high mass loading, are promising electrode materials for ES. Thesis Master of Applied Science (MASc)

No comments. Thanks. Advanced electrodes based on MnO2 for the electrochemical supercapacitor (ES) application have been fabricated using electrochemical and chemical methods. Electrosynthesis method has been utilized for the in-situ impregnation of manganese dioxide in commercial Ni plaque current collectors. Dipping-reduction, cathodic galvanostatic and reverse pulse electrosynthesis methods were investigated. The material loading was varied by the variation of the number of the dipping-reduction procedures in the chemical precipitation method or by the variation of charge passed in the electrochemical methods. The results obtained by different methods were compared. The dipping-reduction method offered the advantage of higher specific capacitances (SCs) at high scan rates, whereas other methods allowed higher material synthesis rate. Cathodic electrolytic deposition (ELD) has been utilized for the fabrication of Ag-doped MnO2 films. The Ag-doped MnO2 films showed improved capacitive behavior and lower electrical resistance of 0.6 Ohm compared to pure MnO2 films. The highest SC of 770 F g-1 was obtained at a scan rate of 2 mV s-1 in the 0.5 M Na2SO4 electrolyte. Electrodes for ES application were fabricated by cathodic electrodeposition of MnO2 on CNTs, which were grown by chemical vapor deposition on stainless steel meshes. The MnO2-CNT nanocomposites showed excellent capacitive behavior and low electrical resistance of 0.5 Ohm. Electrophoretic deposition (EPD) has been utilized for the deposition of composite MnO2-multiwalled carbon nanotube (MWCNT) films for the ES application. Dopamine (DA), caffeic acid (CA), tyramine (TA), gallic acid (GA), polyacrylic acid (PAA) and pyrocatechol violet (PV) were shown to be effective and universal charging additives, which provide stabilization of MnO2 nanoparticles and MWCNTs in the suspensions. The influence of the structure of the organic molecules on their adsorption on the oxide nanoparticles has been investigated. We discovered that the number and site of OH group for dispersants were essential for the adsorption on oxide materials, and the number of aromatic ring was important for the adsorption on carbon materials. Pure CNT films were deposited using PV as a dispersant, which was the first time in literature to prepare pure CNT film using a dispersant. SCs decrease with increasing film thickness. SCs of composite MnO2-MWCNT obtained using EPD were in the range of 350-650 F g-1 depending on material loadings. Doctor of Science (PhD)

Electrochemical methods show great promise in the deposition of biocompatible coatings for biomedical applications with advanced functionality. Consequently, methods of creating coatings of bioactive materials, such as halloysite nanotubes (HNT), hydroxyapatite (HA), chitosan, hyaluronic acid (HYH), poly-L-ornithine (PLO) and poly-L-lysine (PLL) and polyacrylic acid (PAA) have been developed through the use of electrophoretic deposition (EPD). The co-deposition of these materials are achieved at voltages ranging from 5 to 20 V on a 304 stainless steel substrate using suspensions of 0.5 and 1.0 gL-1 biopolymer (chitosan, PAA, PLO, PLL) containing 0.3, 0.5 0.6, 1.0 and 2.0 gL-1 bioceramic (HNT, HA). The resulting films were then investigated to further understand the kinetics and mechanics of deposition, determine their properties, and evaluate their suitability for physiological applications. The films were studied using X-Ray Diffraction (XRD), Differential Thermal Analysis and Thermogravimetric Analysis (DTA/TGA), Scanning Electron Microscopy (SEM), Quartz Crystal Microbalance (QCM) and Linear Polarisation. The results indicate that film thickness, composition and morphology can be controlled and modified at will, and that the deposition of composite films, multilayer laminates and functionally graded films are possible. Master of Applied Science (MASc)

Electrochemical deposition methods have been developed for the fabrication of organic － inorganic nanocomposite coatings. The methods are based on electrophoretic deposition of ceramic nanoparticles and polymers. EPD method has been developed for the deposition of nanostructured TiO2 films using new dispersing agents. The stabilization and charging of the nanoparticles in suspensions was achieved using these organic molecules, which belong to catecholate and salicylate families. Anodic deposition was achieved using caffeic acid, 2,3－dihydroxybenzoic acid, 2,6－dihydroxybenzoic acid and 5－sulfosalicylic acid. Cathodic deposition was performed using 2,4 dihydroxycinnamic acid, p－coumaric acid and trans cinnamic acid. The deposition yield has been studied as a function of the additive concentration and deposition time. The deposition mechanism has been investigated. The fundamental adsorption mechanism is based on the complexation of metal ions at the surfaces of oxide nanoparticles. The method enabled the co-deposition of TiO2 and other oxides and the formation of composite films. Electrophoretic deposition method has been used for the deposition of TiO2 nanoparticles modified with organic dyes. Alizarin red, alizarin yellow, pyrocatechol violet and Aurintricarboxylic acid dyes were used for the dispersion and charging of TiO2. The microstructures of the nanocomposite coatings were studied. The deposition yield was investigated under a variety of conditions. Obtained results could pave the way for the fabrication of dye-sensitized TiO2 films. EPD method has also been developed for the fabrication of (Poly[3-(3-N,N-diethylaminopropoxy)thiophene]) PDAOT－TiO2, (polyethylenimine) PEI－TiO2 and PEI－hydrotalcite composite films. The microstructures of the nanocomposite coatings were studied by Scanning Electron Microscopy, Thermogravimetric Analysis, which showed the co－deposition of inorganic nanoparticles and organic polymer. Electrochemical test of the composite film has been conducted. The results showed that PEI film provided corrosion protection of the stainless steel substrates. Master of Science (MSc)

The electrochemical supercapacitors (ESs) are an emerging technology that promises to play an important role in meeting the demands of automotive and electronic industry. A notable improvement in ES performance has been achieved through recent advances in understanding charge storage mechanisms and the development of advanced nanostructured materials, such as nanostructured MnO2 and composites. The anodic electrophoretic deposition (EPD) method has been developed for the fabrication of MnO2 and composite MnO2-multiwalled carbon nanotubes (MWCNTs) films. The problem of low stability of MnO2 suspensions was addressed by the development of new dispersing agents. Benzoic acid and phenolic molecules, such as 3,4-dihydroxybenzoic acid, 3,4-dihydroxyphenylacetic, 3,4-dihydroxyhydrocinnamic acid, 3,4,5-trihydroxybenzoic acid, salicylic acid, 2,3,4-trihydroxybenzoic acid, aurintricarboxylic acid and aurintricarboxylic acid ammonium salt were investigated as additives for the dispersion and charging of MnO2 nanoparticles. The adsorption of the organic molecules on the MnO2 nanoparticles involved the interaction of COOH groups and OH groups with Mn atoms on the particle surfaces and complexation. The results showed that adjacent OH groups, as well as adjacent OH and COOH groups bonded to the aromatic ring of the phenolic molecules enabled enhanced adsorption of the organic molecules. It was found that EPD of MnO2 and MWCNTs can be achieved using 3,4-dihydroxybenzoic acid, 2,3,4-trihydroxybenzoic acid, and aurintricarboxylic acid as a common dispersants and charging additives. Aurintricarboxylic acid ammonium salt provided a charge required for efficient dispersion and EPD of MWCNTs and graphene. New dispersion methods allowed the formation of composite electrodes by colloidal techniques, such as EPD or slurry impregnation of MnO2 and MWCNTs into advanced current collectors, such as porous nickel foam and nickel plaque. The composite electrodes showed excellent capacitive performance with large material loading in 0.5 M Na2SO4 electrolyte. MnO2 and MWCNTs can form a porous network, which is beneficial for the electrolyte access to the active materials. The effect of the MWCNTs concentration, scan rate and electrodes type on the capacitive behaviour was discussed. It was found that the addition of MWCNTs can improve the capacitive performance of MnO2 electrodes and reduced equivalent series resistance.

This experimental research thesis describes the combination of conjugated polymers and carbon nanotubes with the fields of electrophoretic deposition (EPD) and organic solar cells. Prior to these contributions, soluble conjugated polymers and carbon nanotubes that have been functionalized by them had not yet been deposited by EPD from solution or by using non-toxic solvents. Additionally, EPD had not yet been utilized to deposit the active layer in a solid organic photovoltaic device. The EPD of soluble conjugated polymer functionalized carbon nanotubes from non-toxic solvents was achieved through an iterative process of experimentation and technique refinement. The developed EPD technique utilized the high pH region at the cathode substrate to neutralize positively charged weak polyelectrolytes macromolecules. Their functional groups were protonated using a minimized amount of acetic acid which also enabled their solubility. Deprotonation of the quaternary ammonium functional groups rendered them neutrally charged and insoluble tertiary amines. This mechanism facilitated the formation of coatings that were predictable and uniform in appearance and thickness. Control over coating thickness was demonstrated by coatings spanning 100 nm to 10 μm. These coatings were produced by adjusting the applied voltage, solution concentration, and tuning the deposition duration. Techniques for the fabrication of a photovoltaic device using an active layer produced by EPD were established though modifications of general organic photovoltaic device fabrication procedures. These modifications involved redesigning the photolithographic ITO etching pattern, adding an insulating barrier strip, thickening the aluminum electrode layer, and switching the top buffer layer from LiF to BCP. Master of Applied Science (MASc)

New electrochemical deposition methods have been developed for the fabrication of advanced composite coatings for biosensors applications. The methods are based on electrodeposition of biopolymers, such as cathodic electrodeposition of chitosan, anodic electrodeposition of alginic acid and hyaluronic acid. Another approach is based on electrolytic deposition and electrophoretic deposition of ceramic materials and chitosan. Electrochemical strategies have been discovered for the electrochemical co-deposition of polymers with enzymes, such as glucose oxidase and hemoglobin. Glucose oxidase was used as a model enzyme for the development of new electrochemical strategies for the fabrication of composite coatings for applications in biosensors. New strategies have been further utilized for the fabrication of novel composites containing hemoglobin. It was found that co-deposition of biopolymers and enzymes from the solutions resulted in the fabrication of composite materials which can keep the activity of the enzymes. Electrochemical methods have been developed for the deposition of composite coatings containing ceramic materials (ZnO) in the matrix of chitosan. The composite coatings can be utilized for the immobilization of enzymes by the electrostatic attraction. The composition and microstructure of the composite coatings were investigated. The composition of these nanocomposite coatings can be varied by variation of bath composition for electrodeposition. The deposition yield was studied at various deposition conditions. Electrochemical deposition mechanisms have been investigated and discussed. Obtained results pave the way for the fabrication of novel coatings for immobilization of enzymes and for application in advanced biosensors. Master of Applied Science (MASc)

Electrochemical supercapacitors (ES) have become an attractive technology in electrical energy storage devices and found many applications in a number of areas. The development of ES requires fabrication of advanced electrodes with novel materials and new techniques. Conducting polymer polypyrrole (PPy) has been found to be a promising electrode for ES due to its high pseudo capacitance and good electrical conductivity. The polypyrrole based composite electrode with multiwall carbon nanotubes (MWCNTs) has been proved to enhance the electrochemical performance of ES. Anodic electrochemical deposition of polypyrrole film and composite with MWCNTs has been successfully achieved on a stainless steel substrates in aqueous solutions. Novel additives, such as tiron (4,5-dihydroxy-1,3-benzenedisulfonic acid disodium salt) and sodium salicylate have been employed for the electro-synthesis of PPy. The role of additives in the electrodeposition process have been discussed. The electrochemical properties of PPy and PPylMWCNT composite have been investigated and compared by using different characterization techniques. The results showed that good quality PPy film and PPy/MWCNT composite can be obtained on stainless steel without anodic dissolution of anode using novel additives in aqueous solutions. The PPy films provided corrosion protection for stainless steel in aqueous solutions. High electrochemical performance of PPy film was achieved, the electrochemical behavior of PPy electrodes was significantly enhanced when MWCNTs were incorporated into the film matrix. Hence, investigations in this work indicated that PPy and PPy/MWCNT composite deposited on the stainless steel substrates are promising electrode materials for ES. Master of Applied Science (MASc)

New electrophoretic deposition methods for the fabrication of advanced organic-inorganic composite coatings on metallic substrates for biomedical applications have been developed. In the proposed methods, chitosan was used as a matrix for the fabrication of multilayer and functional graded chitosan- hydroxyapatite (HA) coatings. The HA particles showed preferred orientation of c-axis parallel to the layer surface, which is similar to the bone structure. Electrochemical studies showed that the obtained coatings provided corrosion protection of the metallic substrates, such as stainless steel and Nitinol. The feasibility of co-deposition of chitosan and heparin has been demonstrated. Composite chitosan-heparin layers were used for the surface modification of chitosan-HA coatings. Obtained results paved the way for the electrophoretic fabrication of novel coatings for biomedical implants with improved blood compatibility. The feasibility of co-deposition of hyaluronic acid and HA has also been demonstrated. The co-deposition of hyaluronic acid and HA resulted in the fabrication of novel nanocomposite films by electrodeposition. The chemical composition, microstructure, corrosion protection, and other functional properties of the nanocomposites have been investigated. Co-deposition of hyaluronic acid and multiwalled carbon nanotubes has been studied by TGA/DT A and SEM studies. The feasibility of deposition of novel composites based on alginic acid has been demonstrated. New electrochemical strategies were used for the fabrication of alginic acid-HA, alginic acid-heparin and alginic acid -hyaluronic acid nanocomposites. The composition of these nanocomposite coatings can be varied by variation in bath composition for EPD. The electrochemical mechanisms for the fabrication of all these advanced organic-inorganic composite coatings have been developed. Thesis Master of Applied Science (MASc)

Novel electrodeposition strategies have been developed for the fabrication of thick adherent zirconia ceramic and composite coatings for biomedical applications. The new method is based on the electrophoretic deposition (EPD) of polyelectrolyte additives combined with the cathodic precipitation of zirconia. The method enables the room- temperature electrosynthesis of crystalline zirconia nanoparticles in the polymer matrix. Adherent crack-free coatings up to several microns thick were obtained. The deposits were studied by thermogravimetric and differential thermal analysis, X-ray diffraction analysis, scanning and transmission electron microscopy, and atomic force microscopy. Obtained results pave the way for electrodeposition of other ceramic-polymer composites. Novel advanced nanocomposite coatings based on bioceramic hydroxyapatite (HA) have been developed for the surface modification of orthopaedic and dental implant metals. HA nanoparticles prepared by a chemical precipitation method were used for the fabrication of novel HA-chitosan nanocomposite coatings. The use of chitosan enables room-temperature fabrication of the composite coatings. The problems related to the sintering of HA can be avoided. A new electrodeposition strategy, based on the EPD of HA nanoparticles and electrochemical deposition of chitosan macromolecules, has been developed. The method enabled the formation of dense, adherent and uniform coatings of various thicknesses in the range of up to 60μm. Bioactive composite coatings containing 40.9-89.8 wt% HA were obtained. The deposit composition and microstructure can be tailored by varying the chitosan and HA concentrations in the deposition bath. A mathematical model describing the formation of the HA-chitosan composite deposit has been developed. X-ray studies revealed preferred orientation of HA nanoparticles in the nanocomposites. Obtained coatings provide corrosion protection of the substrates and can be utilized for the fabrication of advanced biomedical implants. For further functionalization of the HA-chitosan composite coating, Ag and CaSi03 have been incorporated into the coating. Novel HA-Ag-chitosan and HA-CaSiO3-chitosan nanocomposite coatings have been deposited as monolayers, laminates, and coatings of graded composition. The obtained results can be used for the development of biocompatible antimicrobial coatings with controlled Ag+ release rate, and nanocomposite coatings with enhanced bioactivity. Thesis Doctor of Philosophy (PhD)

Pure zinc and zinc/yttria stabilized zirconia (YSZ) composite coatings for combined wear and corrosion protection of ferrous substrates were prepared by electrodeposition using acidic zinc sulphate solutions containing YSZ and gelatin. The morphology of the electrodeposit was studied by Field Emission Scanning Electron Microscopy (FESEM) with energy dispersive spectroscopy (EDS). X-ray diffraction was employed to determine the texture of the zinc deposits. In the electrodeposition of pure zinc coatings, the influence of electrodeposition parameters, including current density, deposition time and solution pH was studied. It was found that the deposition rate was controlled by the current density and that an increase in deposition time resulted in the formation of deposit microstructures with coarse, columnar grains. The deposits prepared from solutions with lower pH were composed of uniform, fine grains and exhibited a basal plane preferred orientation. The effects of gelatin on zinc electrodeposition were investigated. It was found that the addition of gelatin profoundly modified the microstructure and crystallographic orientation of the zinc deposit. As the gelatin concentration increased, the mean grain size of zinc deposit was reduced and the basal plane preferred orientation was inhibited. The modification of the microstructure and orientation by gelatin increased microhardness of the zinc coating. However, the corrosion protection property which was assessed by potentiodynamic polarization test was not significantly changed. In the study on composite coatings, the incorporation of ceramic particles in the zinc deposit was characterized as a function of the deposition solution composition. The effect of ceramic particles on the hardness of the composite coatings was assessed by microhardness. The corrosion potential of the composite coating was determined by potentiodynamic polarization tests. The results showed that decrease in solution pH and addition of gelatin promoted the co-deposition of ceramic particles with zinc. The mechanical and corrosion properties of conventional zinc coatings were improved by the incorporation of ceramic particles. Thesis Master of Applied Science (MASc)