Electrodes are modified with polymer films to grant novel permeability. Often, redox probes partition from solution into film and are electrolyzed at the electrode. This creates a flux of probe into the polymer film and a flux of electrolyzed probe out of the polymer film. Transport of the probe through the film is governed by diffusion and migration, mathematically described from the Nernst-Planck equation as J_{i}=-D_{i}((∂C_{i}(x,t))/(∂x))-((z_{i}F)/(RT))D_{i}C_{i}(x,t)((∂Φ(x,t))/(∂x)) where x is the distance from the electrode, t is time, C_{i}(x,t) is space and time dependant concentration of the probe i, z_{i} is the charge of the probe i, F is Faraday's constant, R is the gas constant, T is absolute temperature, J_{i} is the flux of the probe i, D_{i} is the diffusion constant of the probe i and Φ(x,t) is the space and time dependant potential. In most natural systems, charge accumulation is not appreciably noticed, the system behaves in such a way that a charged ion is neutralized by a counterion. This is called electroneutrality and is mathematically represented by Laplace's condition on the potential, ((∂²Φ)/(∂x²))=0. In some systems, it is not clear if counterions are readily available to neutralize an ion. In such a system, there may not be electroneutrality, giving Poisson's equation to replace Laplace's condition as ((∂²Φ)/(∂x²))=-(F/ɛ)∑_{i}z_{i}C_{i}(x,t) where ɛ is the relative permittivity. The addition of Poisson's condition makes the system nonsolvable. In addition, the magnitude of F/ɛ creates difficulty simulating the system using standard techniques. The first system investigated determines the concentration and potential profiles over the polymer membrane of a fuel cell without electroneutrality. In some systems, the probes can not easily diffuse around each other, certain polymer film environments prevent such a swap of location as diffusion is commonly thought to occur. A more generalized form of the Nernst-Planck equation describes spatially varying diffusion coefficient as J=-D(x,t)((∂C(x,t))/(∂x))-((zF)/(RT))D(x,t)C(x,t)((∂Φ(x,t))/(∂x)). D(x,t) is space and time dependent diffusion, usually thought of with a physical diffusion term and an ion hopping term. The second system this thesis investigates is a modified electrode system where electron hopping is responsible for a majority of the probe transport within the film. Lastly, the beginnings of a method are presented to easily determine the physical diffusion rate of a probe within a modified electrode system based on known system parameters.

Three aromatic poly(arylene ether)s P2¡BP3¡BP4 were synthesized from bis(fluoride)4,4¡¨¡¨-Difluoro-3,3¡¨¡¨-bsi-trifluoromethyl-n¡¨-bisphenyl-[1,1¡¦;4¡¦,1¡¨;4¡¨,1¡¨¡¦;4¡¨¡¦,1¡¨¡¨]-quinquephenyl(n¡¨:2¡¨,3¡¨[G2];2¡¨,3¡¨,5¡¨[G3];2¡¨,3¡¨,5¡¨,6¡¨[G4]) with 4,4'-(9-Fluorenylidene)diphenol. The molecular weight of the polymer (Mw: 105-1.6¡Ñ105, PDI:1.5-2.2) was measured by gel permeation chromatography and the structure was confirmed by NMR spectra. Thermal stability was measured using Thermogravimetry and Thermomechanical Analysis. The polymer had a Td at 520¢J ~550¢J, and soft point at 310¢J. Young's modulus of polymer was (1.25-2.5Gpa). This polymer has high strength, modulus of elasticity, and thermal stability. The polymer consists of polyaromatic groups with bisfluoride monomer, (5, 6, 7 aromatic). We hypothesized that sulfonation of the polymer will exhibit high conductivity and great mechanical properties. Ion exchange capacities (IECs) were evaluated by acid¡Vbase titration. We sulfonated the polymer in order to apply to the proton exchange membrane fuel cell. The results showed after sulfonation of P4, IEC is 3.3(meq/g), and sulfonation of P2 showed that its proton conductivity is 75% more than Nafion117 at 80¢J with 0.28(S/cm). Keywords: proton exchange membrane, proton conductivity, Nafion, sulfonated, ion exchange capacity

Fuel cells are promising energy conversion devices, but they have not been widely adopted because of their very high cost. The most expensive component of a fuel cell is the membrane electrode assembly, a polymer film coated with catalyst material. The catalyst layer is fabricated by depositing and drying a liquid ink on the membrane. The membrane can rapidly absorb water from the ink, causing swelling strain sufficient for wrinkling, which can cause defects in the finished product. These challenges limit most catalyst layer fabrication to individual preparation by hand. We seek to understand the swelling phenomenon in a way that enables the control of defects during mass production. Membrane swelling is a transient, three-dimensional, coupled mass transfer, heat transfer and solid mechanics problem. Existing models describe the membrane in fuel cell operating conditions, making use of simplifying assumptions that are not valid for predicting manufacturing defects. We present a new model incorporating effects that are missing from other models. We present simulation results for scenarios relevant to the control of defects. Simple spatial variations in water content can cause curl and wrinkling; we establish criteria for the formation of these defects by simulating the membrane's response when subjected to the full pre-swollen coating and drying process. We investigate the sensitivity of wrinkling to nonuniformity in the coating and to processing conditions in the coating line. We propose a rationale for controlling wrinkling caused by these effects and for diagnosing coating defects using the membrane's wrinkling response. We show how the membrane behaves differently depending on whether the coating is applied to one side or to both sides simultaneously. We have designed and constructed a machine to pre-swell the membrane, apply a coating and then dry the coating under controlled tension, speed, temperature and humidity. We present the design and discuss how the machine may be used, together with the membrane model, to predict and control defects in catalyst-coated membranes. / text

This thesis describes novel microel ectromechanical system (MEMS) based electrochemical gas sensors and methods of fabrication. This thesis presents the research in two parts. In the first part, a method to handle a thin silicon wafer using an electrochemically active adhesive is described. Handling of a thin silicon wafer is an important issue in 3D-IC manufacturing where through silicon vias (TSVs) is an enabling technology. Thin silicon wafers are flexible and fragile, therefore difficult to handle. In addressing the need for a reliable solution, a method based on an electrochemically active adhesive was developed. In this method, an electrochemically active adhesive was diluted and spin coated on a 100 mm diameter silicon wafer (carrier wafer) on which another silicon wafer (device wafer) was bonded. Device wafer was subjected to post processing fabrication technique such as wafer thinning. Successful debonding of the device wafer was achieved by applying a voltage between the two wafers. In another part of the research, a fabrication process for developing a functional nanoporous material using atomic layer deposition is presented. In order to realize a nanoporous electrode, a nanoporous anodized aluminum oxide (AAO) substrate was used, which was functionalized with very thin layers (~ 10 nm) of platinum (Pt) and aluminum oxide (Al2O3) using atomic layer deposition. Nanoporous material when used as an electrode delivers high sensitivity due to the inherent high surface area and is potentially applicable in fuel cells and in electrochemical sensing. The second part of the thesis addresses the need for a high performance gas sensor that is applicable for asthma monitoring. Asthma is a disease related to the inflammation in the airways of the lungs and is characterized by the presence of nitric oxide gas in the exhaled breath. The gas concentration of above approximately 50 parts-per-billion indicates a likely presence of asthma. A MEMS based electrochemical gas sensor was successfully designed and developed to meet the stringent requirements needed for asthma detection. Furthermore, to enable a hand held asthma measuring instrument, a miniaturized sensor with integrated electrodes and liquid electrolyte was developed. The electrodes were assembled at a wafer-level to demonstrate the feasibility towards a high volume fabrication of the gas sensors. In addition, the designed amperometric gas sensor was successfully tested for hydrogen sulphide concentration, which is a bio marker for bad breath. / <p>QC 20150907</p>

This dissertation focuses on the preparation of new Nafion®/ ex-situ silica nanocomposites membranes and the impact of particle size of spherical silica particles on the nanocomposites' properties. To achieve acceptable power production, fuel cell polymer membranes are required with good proton conductivity, water retention, thermal and mechanical stability. However, to avoid poisoning of fuel cell electrocatalysts with CO or other fuel contaminants, they must be operated at temperatures (>100 °C). At these temperatures, fuel cell membranes dehydrate resulting in dramatic decreases in proton conductivity or complete failure as membranes crack due to volumetric stress from water loss. Even if fuel cell is kept in a humidified chamber, increasing temperature will eventually shut the cell down as Nafion®'s bicontinuous structure "dissolves" into a single poorly conducting phase at temperatures above the polymer's Tg.This research provides systematic studies of effects of silica particle size on properties of silica-Nafion® nanocomposites. Results of this study include new insights into requirements for reproducible particle syntheses, practical methods for avoiding silica particle floatation during Nafion® nanocomposite membranes preparation, and a summary of the influence of particle size and functionalization on Nafion® membrane properties. Stober particle syntheses showed high sensitive to ammonia concentration and we discovered that literature procedures' variability is likely due to researchers failure to actually measure ammonia concentration in their aqueous base (which can be 50% or more off). Homogeneous nanocomposite membranes, as determined by AFM and SEM, were successfully prepared using more viscous dispersions. It was observed that nanocomposites membranes with small particles (<50 nm) showed significant increases in proton conductivity at temperatures above 80 °C. Surface modification of the silica particles improved the proton conductivity at 80 °C. Enhancement on proton conductivity was more pronounced with small modified particles at temperatures < 80 °C but unmodified particles were better than modified particles at temperatures >80 °C. Small, unmodified particles led to enhanced thermal stability of the Nafion® ionic domain, however, surface modification did not result in any thermal stability enhancement. Contrary to the expected, mechanical properties of the Nafion® were degraded by adding the silica particles, especially with smaller particles (<50nm).

The Hybrid Sulphur process is one technology out of a multitude of known technologies responsible for hydrogen production. Within the latter hydrogen production cycle, it is pivotal to recover O2 as a by-product from a sulphuric acid decomposition reaction that produces SO2, H2O and O2. It is assumed that a simple phase separation stage carried out on the reaction products would liberate SO2 and O2 as a gaseous mixture leaving behind H2O in the liquid state. Several separation technologies are available to effect SO2/O2 separation, but membrane technology has proved to be dearer due to simplicity of the technology, low capital and energy costs. It is a pity though that insignificant work has been done that considers the SO2/O2 binary system in the membrane technology context. Of the insignificant work done, non – commercial membranes were employed. It is on the latter background that the present study was proposed. Six commercial membranes were selected from literature, two (Udel Polysulfone and Teflon AF 2400) of which are currently used in gas separation applications and the remainder (Hyflon M, Hyflon F, Halar and Nafion 117) not necessarily used as gas separation membranes but present a potential of separating SO2/O2. The inclusion of the latter four membranes sought to unearth unknown gas separation potentials of the membranes based on hypothetical 1 μm thick membranes. A screening technique was employed to eliminate poor performing membranes through pure component permeation of SO2, O2, N2 and CO2. The use of the additional gases (N2 and CO2) was meant to allow the generation of a pool of data that would be used as a yardstick to compare to literature and thus validate the authenticity of the designed set up. The single permeation experiments were carried out at 25°C and at absolute gas feed pressures of 1 bar, 2 bar and 3 bar, with the exception of Hyflon F experiments that were carried out at 3.85 bar, 2.85 bar and 1.85 bar also at 25°C. The effect of pressure on gas permeability and ideal selectivity of all gases against O2 was investigated. Udel Polysulfone and Nafion 117 presented clearly evident pressure dependant SO2 permeabilities whilst CO2, N2 and O2 permeabilities were sluggishly dependant on pressure in all membranes. Gas flux in general increased with increasing pressure as pressure is essentially the driving force for permeability. Membrane screening for further investigation was then performed based on a compromise between SO2/O2 ideal selectivity and SO2 flux in hypothetical 1 μm thick membranes. Membranes that presented the best SO2/O2 selectivity include, Udel Polysulfone with SO2/O2 selectivities of 46, 58 and 314 at 1 bar, 2 bar and 3 bar respectively, Nafion 117 with SO2/O2 selectivities of 30, 35 and 40 at 1 bar, 2 bar and 3 bar respectively and Halar with a SO2/O2 selectivity of 17 at 3 bar. The best SO2 flux through hypothetical 1 μm thick membranes was manifested in Teflon AF 2400 with SO2 fluxes of 3.6 m3.m-2.hr-1, 5.9 m3.m-2.hr-1 and 9.9 m3.m-2.hr-1 at trans-membrane pressures of 1 bar, 2 Bar and 3 Bar respectively, Udel Polysulfone with SO2 fluxes of 0.13 m3.m-2.hr-1, 0.32 m3.m-2.hr-1 and 2.56 m3.m-2.hr-1 at trans-membrane pressures of 1 bar, 2 bar and 3 bar respectively and Nafion 117 with SO2 fluxes of 0.48 m3.m-2.hr-1, 1.03 m3.m-2.hr-1 and 1.79 m3.m-2.hr-1 at 1 bar, 2 bar and 3 bar trans-membrane pressures respectively. Despite Teflon AF 2400 presenting the highest SO2 flux, the poor SO2/O2 ideal selectivity ≈ 1 rendered the membrane unfit for further investigation. The low SO2 flux (0.02 m3.m-2.hr-1) presented by Halar also rendered the membrane unfit for further investigation despite the relatively fair SO2/O2 ideal selectivity of 17. Binary permeation experiments were then performed on Udel Polysulfone and Nafion 117 after passing the single permeation screening test. Gas mixture compositions of (25 wt %:75 wt %, SO2:O2), (50 wt %:50 wt %, SO2:O2) and (75 wt %:25 wt %, SO2:O2) were employed. The binary permeation experiments were carried out at a temperature range of 15°C to 55°C and a SO2 feed partial pressure range of 1.1 ± 0.1 bar to 2.3 ± 0.1 bar. The SO2 permeate composition increased with pressure and decreased with temperature in both Udel Polysulfone and Nafion 117. Udel Polysulfone presented a superior SO2/O2 separation potential, concentrating a (25 wt %:75 wt %, SO2:O2) gas mixture to (94 wt %:6 wt %, SO2:O2) in a single step at 15°C and 2.2 ± 0.1 bar SO2 feed partial pressure. Nafion 117 concentrated the same gas mixture to (87 wt %:13 wt %, SO2:O2) also in a single step at 15 °C and 2.4 ± 0.1 bar SO2 feed partial pressure. Based on hypothetical 1 μm thick membranes, Nafion 117 presented generally high SO2 molar fluxes in mixture with O2 of about a magnitude higher than the SO2 molar fluxes presented in Udel Polysulfone. Also, Nafion 117 proved to be less prone to plasticisation within the pressure range considered. Despite Udel Polysulfone presenting generally lower SO2 molar fluxes, Udel Polysulfone was deemed to be the ideal membrane for the current SO2/O2 separation application as thicknesses of 1 μm of Nafion the perfluorosulfonic acid based membrane are currently unknown and also Udel Polysulfone presented the best SO2/O2 separation capability. The latter findings are envisaged to prompt further research on the production of ultra-thin perfluoro-sulfonic acid based membranes for the current application. / Thesis (MIng (Chemical Engineering))--North-West University, Potchefstroom Campus, 2013

The Hybrid Sulphur process is one technology out of a multitude of known technologies responsible for hydrogen production. Within the latter hydrogen production cycle, it is pivotal to recover O2 as a by-product from a sulphuric acid decomposition reaction that produces SO2, H2O and O2. It is assumed that a simple phase separation stage carried out on the reaction products would liberate SO2 and O2 as a gaseous mixture leaving behind H2O in the liquid state. Several separation technologies are available to effect SO2/O2 separation, but membrane technology has proved to be dearer due to simplicity of the technology, low capital and energy costs. It is a pity though that insignificant work has been done that considers the SO2/O2 binary system in the membrane technology context. Of the insignificant work done, non – commercial membranes were employed. It is on the latter background that the present study was proposed. Six commercial membranes were selected from literature, two (Udel Polysulfone and Teflon AF 2400) of which are currently used in gas separation applications and the remainder (Hyflon M, Hyflon F, Halar and Nafion 117) not necessarily used as gas separation membranes but present a potential of separating SO2/O2. The inclusion of the latter four membranes sought to unearth unknown gas separation potentials of the membranes based on hypothetical 1 μm thick membranes. A screening technique was employed to eliminate poor performing membranes through pure component permeation of SO2, O2, N2 and CO2. The use of the additional gases (N2 and CO2) was meant to allow the generation of a pool of data that would be used as a yardstick to compare to literature and thus validate the authenticity of the designed set up. The single permeation experiments were carried out at 25°C and at absolute gas feed pressures of 1 bar, 2 bar and 3 bar, with the exception of Hyflon F experiments that were carried out at 3.85 bar, 2.85 bar and 1.85 bar also at 25°C. The effect of pressure on gas permeability and ideal selectivity of all gases against O2 was investigated. Udel Polysulfone and Nafion 117 presented clearly evident pressure dependant SO2 permeabilities whilst CO2, N2 and O2 permeabilities were sluggishly dependant on pressure in all membranes. Gas flux in general increased with increasing pressure as pressure is essentially the driving force for permeability. Membrane screening for further investigation was then performed based on a compromise between SO2/O2 ideal selectivity and SO2 flux in hypothetical 1 μm thick membranes. Membranes that presented the best SO2/O2 selectivity include, Udel Polysulfone with SO2/O2 selectivities of 46, 58 and 314 at 1 bar, 2 bar and 3 bar respectively, Nafion 117 with SO2/O2 selectivities of 30, 35 and 40 at 1 bar, 2 bar and 3 bar respectively and Halar with a SO2/O2 selectivity of 17 at 3 bar. The best SO2 flux through hypothetical 1 μm thick membranes was manifested in Teflon AF 2400 with SO2 fluxes of 3.6 m3.m-2.hr-1, 5.9 m3.m-2.hr-1 and 9.9 m3.m-2.hr-1 at trans-membrane pressures of 1 bar, 2 Bar and 3 Bar respectively, Udel Polysulfone with SO2 fluxes of 0.13 m3.m-2.hr-1, 0.32 m3.m-2.hr-1 and 2.56 m3.m-2.hr-1 at trans-membrane pressures of 1 bar, 2 bar and 3 bar respectively and Nafion 117 with SO2 fluxes of 0.48 m3.m-2.hr-1, 1.03 m3.m-2.hr-1 and 1.79 m3.m-2.hr-1 at 1 bar, 2 bar and 3 bar trans-membrane pressures respectively. Despite Teflon AF 2400 presenting the highest SO2 flux, the poor SO2/O2 ideal selectivity ≈ 1 rendered the membrane unfit for further investigation. The low SO2 flux (0.02 m3.m-2.hr-1) presented by Halar also rendered the membrane unfit for further investigation despite the relatively fair SO2/O2 ideal selectivity of 17. Binary permeation experiments were then performed on Udel Polysulfone and Nafion 117 after passing the single permeation screening test. Gas mixture compositions of (25 wt %:75 wt %, SO2:O2), (50 wt %:50 wt %, SO2:O2) and (75 wt %:25 wt %, SO2:O2) were employed. The binary permeation experiments were carried out at a temperature range of 15°C to 55°C and a SO2 feed partial pressure range of 1.1 ± 0.1 bar to 2.3 ± 0.1 bar. The SO2 permeate composition increased with pressure and decreased with temperature in both Udel Polysulfone and Nafion 117. Udel Polysulfone presented a superior SO2/O2 separation potential, concentrating a (25 wt %:75 wt %, SO2:O2) gas mixture to (94 wt %:6 wt %, SO2:O2) in a single step at 15°C and 2.2 ± 0.1 bar SO2 feed partial pressure. Nafion 117 concentrated the same gas mixture to (87 wt %:13 wt %, SO2:O2) also in a single step at 15 °C and 2.4 ± 0.1 bar SO2 feed partial pressure. Based on hypothetical 1 μm thick membranes, Nafion 117 presented generally high SO2 molar fluxes in mixture with O2 of about a magnitude higher than the SO2 molar fluxes presented in Udel Polysulfone. Also, Nafion 117 proved to be less prone to plasticisation within the pressure range considered. Despite Udel Polysulfone presenting generally lower SO2 molar fluxes, Udel Polysulfone was deemed to be the ideal membrane for the current SO2/O2 separation application as thicknesses of 1 μm of Nafion the perfluorosulfonic acid based membrane are currently unknown and also Udel Polysulfone presented the best SO2/O2 separation capability. The latter findings are envisaged to prompt further research on the production of ultra-thin perfluoro-sulfonic acid based membranes for the current application. / Thesis (MIng (Chemical Engineering))--North-West University, Potchefstroom Campus, 2013

Les membranes Nafion©, composant essentiel des piles à combustibles (PEMFC), ont des performances liées à leur hydratation. En collaboration avec le CEA, nous avons développé une méthode de mesure de la vitesse ultrasonore et du gonflement de ce type de membranes par insertion-substitution. Conséquence de la faible épaisseur des échantillons devant la longueur d'onde, un phénomène de recouvrement apparait entre les différents échos d'aller-retour dans le matériau. Un algorithme de Matching Pursuit a été adapté au cas des membranes afin de déconvoluer les échos et ainsi de permettre la mesure de la vitesse de propagation ultrasonore et de l'atténuation. Nos mesures nous ont également permis de déterminer l'épaisseur de ces membranes. Une étude sur la robustesse et le domaine de validité de notre méthode de traitement est présentée. Ce manuscrit recense également l'ensemble des résultats sur la caractérisation des membranes Nafion dans différents états d'équilibre hydrique, attestant de la possibilité de caractériser la reprise hydrique de ce polymère par méthode ultrasonore. / No summary available

Além da necessidade do desenvolvimento de novos eletrocatalisadores para aplicação em células à combustível, há também a necessidade da diminuição do crossover, que compromete a eficiência da reação de oxidação do combustível. Sendo assim, foi realizada neste trabalho a dopagem das membranas de Nafion® 117 com nanopartículas de \'PT\' e \'PT\'/\'RU\', em duas concentrações diferentes de platina, pelo método de absorção-redução. Os resultados de Absorção Atômica e a coloração das amostras comprovaram a absorção da solução de precursores metálicos pela membrana. Os dados de FTIR-ATR e DRX mostraram que houve a formação de nanopartículas. Pelos testes em células unitárias (PEMFC, DMFC e DEFC), observou-se que tanto a PEMFC como a DEFC apresentaram uma melhora na eficiência. Apesar de ter havido um ganho significativo de densidade de potência, de até 50%, com membranas dopadas, não foi possível eliminar o crossover. Entretanto, no caso da DEFC, encontrou-se uma alta porcentagem de produtos oxidados com dois átomos de carbono na saída do cátodo. Os principais produtos formados foram acetaldeído e ácido acético, sendo que o ácido acético foi o produto majoritário. Também foram detectados traços de ácido fórmico comprovando que houve, em menor escala, a quebra da ligação C-C. Além disso, os resultados mostraram que a dopagem das membranas de Nafion® parece ter conferido uma melhora na durabilidade das amostras, já que estas, quando comparadas à membrana sem partículas metálicas, alcançaram maiores densidades de correntes. Finalmente, a dopagem da membrana e a elevação de temperatura provocaram um melhor desempenho nas DEFCs testadas. / Beyond the necessity of the development of new electrocatalysts for fuel cell application, there is also the necessity of diminishing of the crossover that compromises the oxidation efficiency of the fuel. So, in this work was carried out the doping of the Nafion® 117 membranes with \'PT\' and \'PT\'/\'RU\' nanoparticles in two different platinum concentrations by using the absorption-reduction method. The Atomic Absorption results and the color of the samples proved that the absorption of the metallic precursor solutions by the membrane happened. FTIR-ATR and XRD data showed the formation of nanoparticles. It was observed that in unitary fuel cells (PEMFC, DMFC and DEFC) tests the PEMFC and DEFC showed an improvement in the efficiency. Although a significant increase in the power density, up to 50 % by using doped membranes, it was not possible to eliminate the crossover. However, in the case of the DEFC, a high percentage of oxidized products with two carbon atoms was found in the cathode exit. The main formed products were acetaldehyde and acetic acid, being the acetic acid the majority product. Traces of formic was also detected demonstrating that, in lesser scale, the break of the C-C bond is feasible. Moreover, the results showed that the durability of the doped Nafion® membranes is higher than the membrane without metallic particles, since bigger current densities were reached in the former case. Finally, the membrane doping and the temperature rise led the DEFC to the best performance.

Per-Fluoro-Sulphonic-Acid (PFSA) ionomers have been singled out as the preferable ionomers for making the Polymer Electrolyte Membrane Fuel Cells (PEMFC) membranes owing to their extensive intrinsic chemical stability and super sulfonic acid strength which is core to the PEMFC proton conductivity. This thesis presents a deeper analysis into these PFSA ionomer membrane electrode assemblies (MEA), presenting an electrochemical-analytical comparative analysis of the two basic types, which are the Long-Side-Chain (LSC) Nafion® and the ShortSide-Chain (SSC) Aquivion® ionomer MEA with emphasis on performance and durability which are currently not well understood. In particular, electrochemical circuit models and semiempirical models were employed to enable distinguishable comparative analysis. Also, in this thesis, we present a further probe into the effect of ionomer ink making processes, critically investigating the effect of the High Share Dispersion (HSD) process on both the Nafion® and Aquivion® ionomer membrane electrode assembly (MEA). The findings in this research provides a valuable insight into the performance and durability of PFSA ionomer membrane under various application criteria. The effect of operating parameters and accelerated stress testing (AST) on the PFSA ionomers was determined using electrochemical impedance spectroscopy (EIS) and electronic circuit model (ECM) analysis. The result of this study, shows that the ionomer ink making process for Nafion® and Aquivion® MEAs are not transferrable. Analysis of the PEMFC performance upon application of the high shear dispersion (HSD) process showed that Nafion® MEA had a 10.47% increase in voltage while the Aquivion® MEA had a 2.53% decrease in voltage at current density of 1.14A/cm2 . Also, upon accelerated stress testing, the Nafion® showed a 10.49% increase in its voltage while the Aquivion® on the other hand had a 7.16% decrease in voltage at 0.66A/cm2 . Thus indicating the HSD process enhances the performance of the Nafion® MEA and inhibits the performance of the Aquivion® MEA.