Recent advances in the field of bionanotechnology have enabled researchers to design a variety of tools to detect, image and monitor biological process in cells. Despite this progress, the limited understanding of nanomaterial-cellular interactions has hindered the widespread use of these nanomaterials in biological systems. In this thesis, we examined the potential effects of metallic nanoparticle geometry on important cellular processes such as membrane trafficking, intracellular transport and subcellular signalling. We found that the size of nanoparticles plays an important role on their ability to interact with the cell surface receptors thus dictating their subsequent ability to activate intracellular signalling cascades. Interestingly, trafficking of these nanoparticles was dependent on their size due to biochemical and thermodynamical constraints. These findings suggest that nanomaterials actively interact with biological systems, thus, directly modulating vital cellular processes. In addition, by utilizing various physical and chemical properties of nanomaterials, we developed a novel class of hybrid nanoscaled carrier systems capable of delivering semiconductor quantum dots (QDs) into live cells without inducing membrane damage. Using biodegradable polymeric nanoparticles, bioconjugated QDs were encapsulated and delivered into trafficking vesicles of live cells. The environmentally sensitive surface charge of the polymeric nanoparticles exhibited positive zeta potential inside acidic endo-lysosomes, thus enabling their escape from the vesicular sequestration into the cytosol. Hydrolytic-induced degradation then releases the bioconjugate QDs for active labelling of subcellular structures for real-time studies. Unlike previously described intracellular QD delivery methods, the proposed system offers an efficient way to non-invasively deliver bioconjugated QDs without inducing cell damage, enabling researchers to accurately monitor cellular processes in real-time. The understanding of both physical and chemical properties of nanomaterials is crucial to the design of biocompatible nanosystems to study fundamental processes in biological systems. Here, we demonstrated that both the size and surface chemistry of nanoparticles can be modified to obtain desired biological responses. Future experimental efforts to study other physical and chemical properties could allow the development of more sophisticated and effective platforms for biological applications.

The focus of this work was to understand the fundamental dispersion mechanism of cellulose based nanofibers in bionanocomposites. The cellulose nanofibers were extracted from soybean pod and hemp fibers by chemo-mechanical treatments. These are bundles of cellulose nanofibers with a diameter ranging between 50 to 100 nm and lengths of thousands of nanometers which results in very high aspect ratio. In combination with a suitable matrix polymer, cellulose nanofiber networks show considerable potential as an effective reinforcement for high quality specialty applications of bio-based nanocomposites. Cellulose fibrils have a high density of –OH groups on the surface, which have a tendency to form hydrogen bonds with adjacent fibrils, reducing interaction with the surrounding matrix. The use of nanofibers has been mostly restricted to water soluble polymers. This thesis is focused on synthesizing the nanocomposite using a solid phase matrix polypropylene (PP) or polyethylene (PE) by hot compression and poly (vinyl alcohol) (PVA) in an aqueous phase by film casting. The mechanical properties of nanofiber reinforced PVA film demonstrated a 4-5 fold increase in tensile strength, as compared to the untreated fiber-blend-PVA film. It is necessary to reduce the entanglement of the fibrils and improve their dispersion in the matrix by surface modification of fibers without deteriorating their reinforcing capability. Inverse gas chromatography (IGC) was used to explore how various surface treatments would change the dispersion component of surface energy and acid-base character of cellulose nanofibers and the effect of the incorporation of these modified nanofibers into a biopolymer matrix on the properties of their nano-composites. Poly (lactic acid) (PLA) and polyhydroxybutyrate (PHB) based nanocomposites using cellulose nanofibers were prepared by extrusion, injection molding and hot compression. The IGC results indicated that styrene maleic anhydride coated and ethylene-acrylic acid coated fibers improved their potential to interact with both acidic and basic resins. From transmission electron micrograph, it was shown that the nanofibers were partially dispersed in the polymer matrix. The mechanical properties of the nanocomposites were lower than those predicted by theoretical calculations for both nanofiber reinforced biopolymers.

The discovery of highly efficient organic light-emitting diodes (OLEDs) in the 1980s has stimulated extensive research on organic semiconductors and devices. Underlying this breakthrough is the realization of the organic heterojunction (OH). Besides OLEDs, the implementation of the OH also significantly improves the power conversion efficiency in organic photovoltaic cells (OPVs). The continued technological advancements in organic electronic devices depend on the accumulation of knowledge of the intrinsic properties of organic materials and related interfaces. Among them, charge-carrier transport and carrier injection are two key factors that govern the performance of a device. This thesis mainly focuses on the charge carrier injection and transport at organic heterojunctions. The carrier transport properties of different organic materials used in this study are characterized by time-of-flight (TOF) and admittance spectroscopy (AS). An injection model is formulated by considering the carrier distribution at both sides of the interface. Using a steady-state simulation approach, the effect of accumulated charges on energy level alignment at OH is revealed. Instead of a constant injection barrier, it is found that the barrier varies with applied voltage. Moreover, an escape probability function in the injection model is modified by taking into account the total hopping rate and available hopping sites at the interface. The model predicts that the injection current at low temperature can be dramatically modified by an extremely small density of deep trap states. More importantly, the temperature dependence of the injection current is found to decrease with increasing barrier height. This suggests that extracting the barrier height from the J vs 1/T plot, as commonly employed in the literature, is problematic. These theoretical predictions are confirmed by a series of experiments on heterojunction devices with various barrier heights. In addition, the presence of deep trap states is also consistent with carrier mobility measurements at low temperature. From the point of view of application, an interface chemical doping method is proposed to engineer the carrier injection at an organic heterojunction. It is found that the the injection current can be effectively increased or suppressed by introducing a thin (2 nm) doped organic layer at the interface. This technique is further extended to study the impact of an injection barrier at the OH. in OLEDs, on device performance. It is shown that a 0.3 eV injection barrier at the OH, that is normally negligible at metal/organic interface, can reduce the device efficiency by 25 %. This is explained by the carrier distribution in the density-of-states at the OH. Furthermore, the carrier transport properties in a bulk heterojunction system are investigated. The bulk heterojunction consists of an interpenetrating network of a polymeric electron donor and a molecular electron acceptor. This material system has been studied in the last few years as an attractive power conversion efficiency (5% under AM 1.5) of OPV cells has been demonstrated. It is found that the electron mobility is greatly dependent on the thermal treatment of the film. Interfacial dipole effect at the heterojunction between the donor and the acceptor is proposed to be the determining factor that alters the carrier mobility in different nano-scale structures.

The integration of high voltage power transistors with control circuitry to form smart Power Integrated Circuits (PIC) has numerous applications in the areas of industrial and consumer electronics. These smart PICs must rely on the availability of high performance power transistors. In this thesis, a vertical U-shaped gate MOSFET (UMOS) and a lateral Extended Drain MOSFET (EDMOS) with enhanced electrical characteristics are proposed, developed and verified via experimental fabrication. The proposed new process and structure offers superior performance, such as low on-resistance, low gate charge and optimized high breakdown voltage. In the vertical power UMOS, a novel trenched Local Oxidation of Silicon (LOCOS) process has been applied to the vertical gate structure to reduce the gate-to-source overlap capacitance (Cgs). A 40% reduction in Cgs is achieved when compared to conventional UMOS. A specific on-resistance Ron, sp = 60m2·mm2 is observed, which is 45% better than that of the conventional UMOS. The improvement in the device’s Figure-of-Merit (FOM = Ron × Qg) is about 58%. A floating RESURF EDMOS (BV=55V, Ron,sp=36.5m2·mm2) with a 400% improvement in the Safe Operating Area (SOA) when compared to the conventional EDMOS structure is also presented. The proposed EDMOS employs both drain and iii source engineering to enhance SOA, not only via reducing the base resistance of the parasitic bipolar transistor, but also suppressing the base current of the parasitic bipolar transistor under high Vgs and high Vds conditions. A buried deep Nwell allows the device to have better trade-off between breakdown voltage and on-resistance. Finally, in order to achieve low gate charge in the EDMOS, a novel orthogonal gate electrode is proposed to reduce the gate-to-drain overlap capacitance (Cgd). The orthogonal gate has both horizontal and vertical sections for gate control. This device is implemented in a 0.18?m 30V HV-CMOS process. Compared to a conventional EDMOS with the same voltage and size, a 75% Cgd reduction is observed. The FOM is improved by 53%.

Polymer bead foams are manufactured through a sintering process using foamed polymer beads. It is worth emphasis that the bead foam technology is the only process that can produce 3-dimensionally shaped foam products with ultra-low densities. This unique feature of bead foam process has been attracting enormous attentions from various foam industries. However the conventional bead foam processes still have some limitations associated with manufacturing productivity and safety during the treatment. This thesis deals with novel approaches to innovative and cost-effective manufacturing processes for polystyrene (PS) and polypropylene (PP) bead foam materials, based on thorough understanding of the scientific issues in bead foam technologies. This study also demonstrates the feasibility of new processes by conducting a series of foaming experiments such as batch foaming and continuous extrusion foaming as well as steam chest molding which is a critical common process for all bead foam products. In addition, this study aimed at developing new bead foam processes based on the relationship between the cellular structure and processing/material parameters. When it comes to expandable PS (EPS) bead process, research efforts have been made to eliminate n-pentane which has some disadvantages related to its flammability and low boiling temperature. In addition, the bi-celullar PS foams that feature the superior thermal-insulation property was manufactured through continuous extrusion foaming process. With regard to expanded PP (EPP) bead process, research efforts were focused on the development of cost-effective continuous foaming process in order to resolve the high cost issue of conventional EPP beads. These research strategies were designed on the basis of the comprehension of thermoplastic foaming, steam chest molding process and gas dissolution/diffusion phenomena. The results in the thesis provided considerable introductory and advanced knowledge about the bead foam technologies so that further promising researches can be performed to invent entirely new bead foam materials such as ultrahigh–temperature-durable bead foam products, biodegradable bead foams, other highly functional bead foam products aside from EPS and EPP bead foams.

A sustainable electroless copper coating process was developed for plating automotive fasteners shaped from AISI 9255 low carbon, high silicon steel. The objective was to minimize the ionic and organic species present in each step of the plating process. A sulfuric acid solution inhibited with quinine was defined to clean the steel prior to plating. The corrosivity of the solution was examined through electrochemical and weight loss measurements to evaluate the efficiency of the cleaning process at high temperatures and high acid concentrations. An electroless copper coating process was then developed using a simple copper sulfate chemistry inhibited with quinine to extend the possible operating window. Finally, benzotriazole was evaluated as a possible anti-oxidant coating. Accelerated thioacetamide corrosion tests were used to evaluate the corrosion inhibition of benzotriazole on copper coatings.

A sustainable electroless copper coating process was developed for plating automotive fasteners shaped from AISI 9255 low carbon, high silicon steel. The objective was to minimize the ionic and organic species present in each step of the plating process. A sulfuric acid solution inhibited with quinine was defined to clean the steel prior to plating. The corrosivity of the solution was examined through electrochemical and weight loss measurements to evaluate the efficiency of the cleaning process at high temperatures and high acid concentrations. An electroless copper coating process was then developed using a simple copper sulfate chemistry inhibited with quinine to extend the possible operating window. Finally, benzotriazole was evaluated as a possible anti-oxidant coating. Accelerated thioacetamide corrosion tests were used to evaluate the corrosion inhibition of benzotriazole on copper coatings.

An experimental study was undertaken to quantify the rate of DRI decarburization in a steelmaking slag using the constant–volume pressure increase technique. Experiments were conducted by dropping DRI pellets into molten slag at temperatures from 1500°C to 1600°C. Further experiments were carried out in which the DRI pellets were preheated while the slag temperature remained constant. The effect of initial carbon content and preheating temperature of the DRI on the reaction rate was investigated. The decarburization of DRI appears to comprise of two stages; reaction with the FeO of DRI, followed by further decarburization through the iron oxide of slag. Carbon has a significant effect on the kinetics of both stages while the preheating temperature mainly influences the rate of the reaction between FeO and carbon inside the pellet.

In the past, hardness measurements on nanocrystalline metals were limited to Vickers micro-hardness and nano-indentation tests, mainly due to sample size/thickness limitations. On the other hand, most industries require hardness values on the Rockwell scale and make extensive use of hardness conversion relationships for various hardness scales. However, hardness conversions currently do not exist for nanocrystalline metals. With recent advances in electrodeposition technology, thicker specimens with a wide range of grain sizes can now be produced. In this study, the relationships between Vickers and Rockwell hardness scales have been developed for such materials. In addition, hardness indentations were used to gain further insight into the work hardening of nanocrystalline and polycrystalline nickel. Vickers microhardness and nano-indentation profiles below large Rockwell indentations showed that polycrystalline nickel exhibited considerable strain hardening, as expected. On the other hand, for nanocrystalline nickel the micro-Vickers and nano-indentations hardness profile showed low strain hardening capacity.

A sustainable electroless copper coating process was developed for plating automotive fasteners shaped from AISI 9255 low carbon, high silicon steel. The objective was to minimize the ionic and organic species present in each step of the plating process. A sulfuric acid solution inhibited with quinine was defined to clean the steel prior to plating. The corrosivity of the solution was examined through electrochemical and weight loss measurements to evaluate the efficiency of the cleaning process at high temperatures and high acid concentrations. An electroless copper coating process was then developed using a simple copper sulfate chemistry inhibited with quinine to extend the possible operating window. Finally, benzotriazole was evaluated as a possible anti-oxidant coating. Accelerated thioacetamide corrosion tests were used to evaluate the corrosion inhibition of benzotriazole on copper coatings.