No description available.

No description available.

All oxide heterostructure Cr2O3/TiO2-x was deposited on Al2O3(0001) single crystal via MBE. The analysis of interfacial interactions involving two metal oxides resulting in magnetic properties gave insights for using such heterostructures as potential spintronic device materials. The corundum phase epitaxial growth of TiO2-x on Al2O3 was characterized using XPS, AES, EELS, and LEED. The data obtained gives evidence of presence of two-dimensional electron gas at titania surface due to oxygen vacancies formation after deposition. On titania, the deposition of chrome in UHV results in the formation of oxidized chromia overlayer by abstraction of oxygen from the TiO2-x underlayer further increasing the number of vacancies present. In industrial R&D project, dry etching of multiple optical device components was performed using a novel angled etch prototype tool. The first set of experiments involved plasma etching of SiC thin films optimized for target application. The best-known method (BKM) worked from 300mm full wafer to 200mm product. In second experimentation, a variety of gray-tone photoresist received from customers were etched using BKM. Customer received etch rate on each gray-tone material. The third experiments compared recipe R1 to test recipe R2 on the test vehicle VDC. R2 showed faster etch rate but lower process repeatability (RMSE%). With continuous improvement of the tool and the process, two tools are operating products every day, a third prototype tool is about to be in pilot production.

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<p>The aim of the project was to modify polydimethylsiloxane (PDMS) surfaces in order to minimize adsorption of proteins. PDMS is used in micro-fluidic devices that control the delivery of samples to a sensor chip in Biacore instrumentation. These instruments are used to characterize interactions between biomolecules with a detection principle based on surface plasmon resonance (SPR). To minimize adsorption of proteins poly-ethylene-oxide (PEO) based surfactants, were added to the buffer. The added PEO surfactants were P20, Pluronic F-127 and Brij 35. Interaction of these surfactants with the sensor chip in Biacore instruments was also examined. Creating a more hydrophilic surface layer on PDMS by oxidation was also examined.</p><p>When surfactants were continuously added to protein samples, as in dynamically coating of PDMS surfaces, Brij 35 resulted in the strongest reduction in protein adsorption. Brij 35 was also the surfactant that was easiest to remove from both PDMS and the sensor surfaces. Pluronic bound strongest to surfaces, and is most suitable when only adding surfactant to the buffer in a pre-coating step. All surfactants did reduce protein adsorption considerably (99% or more) and addition is necessary when working with protein solutions and hydrophobic surfaces as PDMS. Another alternative is oxidation of PDMS surface, which is an easy procedure that decreased the protein adsorption to about 10% compared to adsorption to untreated surface.</p>

The aim of the project was to modify polydimethylsiloxane (PDMS) surfaces in order to minimize adsorption of proteins. PDMS is used in micro-fluidic devices that control the delivery of samples to a sensor chip in Biacore instrumentation. These instruments are used to characterize interactions between biomolecules with a detection principle based on surface plasmon resonance (SPR). To minimize adsorption of proteins poly-ethylene-oxide (PEO) based surfactants, were added to the buffer. The added PEO surfactants were P20, Pluronic F-127 and Brij 35. Interaction of these surfactants with the sensor chip in Biacore instruments was also examined. Creating a more hydrophilic surface layer on PDMS by oxidation was also examined. When surfactants were continuously added to protein samples, as in dynamically coating of PDMS surfaces, Brij 35 resulted in the strongest reduction in protein adsorption. Brij 35 was also the surfactant that was easiest to remove from both PDMS and the sensor surfaces. Pluronic bound strongest to surfaces, and is most suitable when only adding surfactant to the buffer in a pre-coating step. All surfactants did reduce protein adsorption considerably (99% or more) and addition is necessary when working with protein solutions and hydrophobic surfaces as PDMS. Another alternative is oxidation of PDMS surface, which is an easy procedure that decreased the protein adsorption to about 10% compared to adsorption to untreated surface.

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No description available.

The properties of materials, especially of solids, can be attributed mainly to the phenomena occurring at the surface. Surface engineering deals with altering the surface properties of materials to realize useful functionalities like wear and corrosion resistance, biocompatibility, hardening etc. Among the various methods adopted, plasma surface modification stands out, because of the inherent dry processing nature and little amount of left over chemicals. In conventional plasma systems, the process is carried out in a low pressure environment. This restricts its use in treating vacuum incompatible materials including tissues and bio-medical samples. Moreover, the batch processing nature and use of expensive vacuum pumps put a bottle-neck in the throughput of any production line. The subject matter of this thesis is about developing and optimizing an atmospheric pressure (760 torr) plasma system and to use it for surface modification of polymers. The experimental system developed, consists of two parallel electrodes facing each other, each of which is covered with a dielectric plate. A gap of 4mm exists between the dielectric surfaces, through which an axial flow of the working gas is maintained. When a high voltage is applied across the electrodes, the gas breaks down, creating plasma. The surface of the sample kept in this plasma, undergoes various phenomena, depending on the power applied, type of gas used and gas flow rate. To drive the plasma a high voltage power supply, which is able to generate 10 kV at 5.8 kHz, was developed in the laboratory. By varying the process parameters, the inherent filamentary nature of discharge can be converted to a diffuse uniform glow. The purity of plasma was studied and established by analyzing the optical emission from the plasma. After optimizing the system, it was used to modify the surface properties of polyester sheets. The wetting nature was altered using fluorocarbon and oxygen plasmas, realizing hydrophobic and hydrophilic surfaces. The contact angle of a water droplet made with the surface changed from 72° to 84° degree for hydrophobic and to 22° for hydrophilic surfaces respectively. Through this investigation, an insight to the procedure for developing an Atmospheric glow discharge system was developed. The details about system frame work, the power supply, electrical and optical characterization of the plasma, are well studied and recorded. The work establishes the various parameters to be varied to convert the filamentary discharge to a uniform glow. Purity of the plasma has been studied extensively and the system design and process values essential for maintaining the purity have been dealt with. Finally the plasma was put in use for surface modification of polymers, and the surface wetting nature alteration was studied and quantified.