Dr. Gregory Shaun Watson Profile

Dr. Gregory Shaun Watson

at Griffith Univ

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Publications (14)

Proceedings Article | 4 January 2006 Paper

Lithography of diamond-like-carbon (DLC) films for use as masters in soft lithography

Gregory Watson, Sverre Myhra, Jolanta Watson

Proceedings Volume 6037, 60371C (2006) https://doi.org/10.1117/12.638361

KEYWORDS: Lithography, Polymers, Oxides, Atomic force microscopy, Optical lithography, Silicon, Fabrication, Scanning probe microscopy, Carbon, Oxidation

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Micron sized structures/components are commonly employed in a variety of devices (e.g., biosensors, array devices). At present such devices are based on macroscopic technologies. Future applications of differentiated structures/surfaces are expected to place considerable demands on down-sizing technologies, i.e. enable meso/nanoscopic manipulation. An emerging set of methods known collectively as soft lithography is now being utilised for a large variety of applications including micromolding, microfluidic networks and microcontact printing. In particular stamps and elastomeric elements can be formed by transfer of a pattern to a polymer by a master. The 'master' can be fabricated by a variety of techniques capable of producing well-defined surface topographies. Established lithographic techniques used in the microelectronic industry, such as photolithography, are generally used to fabricate such master templates at the micron scale. A number of polymers can be used to transfer patterns. One of the most widely used polymers for pattern transfer has been polydimethylsiloxane (PDMS). The elastomer is chemically resistant, has a low surface energy and readily conforms to different surface topographies. Obtaining a master is the limiting factor in the production of PDMS replicas. In this study we demonstrate the use of Diamond-Like-Carbon (DLC) as a master template for producing PDMS micro/nano stamps and 3 dimensional PDMS structures. Intricate surface relief patterns were formed on the DLC surface from lithographic techniques by Atomic Force Microscopy (AFM) operated in the electrical conductivity mode. Attributes of the technique include: -Features with line widths less than 20 nm can be formed on the DLC. -The radius of curvature at edges can be less than 10 nm. -The slope of the features is limited by the aspect ratio of the tip. -Highly complex shapes can be fashioned. -Feature depth can be controlled by DLC film thickness and/or by the bias voltage applied. -The master is highly durable. -The master relief after patterning is extremely flat.

Proceedings Article | 30 December 2005 Paper

Tunable natural nano-arrays: controlling surface properties and light reflectance

Jolanta Watson, Sverre Myhra, Gregory Watson

Proceedings Volume 6037, 60371D (2005) https://doi.org/10.1117/12.638366

KEYWORDS: Reflectivity, Coating, Atomic force microscopy, Reflection, Refractive index, Antireflective coatings, Scanning electron microscopy, Eye, Nipple, 3D image processing

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Proceedings Article | 30 December 2005 Paper

Patterning frictional differentiation to a polymer surface by atomic force microscopy

Gregory Watson, Christopher Brown, Sverre Myhra, Nicolas Roch, Simon Hu, Jolanta Watson

Proceedings Volume 6037, 60371B (2005) https://doi.org/10.1117/12.638345

KEYWORDS: Polymers, Raster graphics, Atomic force microscopy, Optical lithography, Image resolution, Lithography, Chemistry, Biosensors, Scanning probe microscopy, Silicon

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Proceedings Article | 23 February 2005 Paper

Protein folding and unfolding by force microscopy: a novel inverse methodology

Gregory Watson, Jolanta Watson, Christopher Brown, Sverre Myhra

Proceedings Volume 5650, (2005) https://doi.org/10.1117/12.582646

KEYWORDS: Proteins, Magnetism, Atomic force microscopy, Molecules, Chemical elements, Microscopy, Chemistry, Optical imaging, Diagnostics, Biosensing

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It has been shown recently that it is possible to reverse-engineer the folding of complex proteins by an AFM-based force versus distance methodology. In essence, the protein is attached to a functionalised surface, then linked to a functionalized tip of a force-sensing/imposing lever, and finally stretched by withdrawal of the probe. The experiments are technically demanding, and subject to a number of artefacts. Moreover, the unfolding process cannot readily be reversed. A 'reverse’ methodology is possible in principle and is likely to provide greater insight into the folding/unfolding sequence. The protein in question will now be attached to a functionalized superparamagnetic bead in solution. A functionalized probe is then introduced into solution whereupon the protein (and its bead) attaches itself to the tip of the probe, while being tracked optically. The system is then submerged in an inhomogeneous magnetic dipole field, giving rise to a magnetic dipole-dipole interaction with the bead. The resultant force will stretch the protein, while being monitored at a force resolution of ca. 1 pN by the deflection of the lever. The significant aspect of the scheme is that the probe acts as a position-sensitive element as well as being a force-sensing device. The field gradient and its rate of change within the interaction volume can readily be controlled to 1 part in 10⁶, and can be reversed. Thus the unfolding/folding sequence can be retraced for the same molecule. Moreover, information about kinetics will be accessible from varying the rate of change in field strength, and the effects of ambient fluid conditions can be investigated in real time with a flow-through arrangement. The proposed methodology is likely to be more userfriendly as a result of dispensing with the functionalized surface, and by being able to determine optically that a single functionalized bead has arrived at the probe tip. Elements of the experimental arrangement are currently at the design stage.

Proceedings Article | 23 February 2005 Paper

Tip-induced nanoscale manipulation of Si and DLC surfaces: the state of the tip

Sverre Myhra, Gregory Watson

Proceedings Volume 5650, (2005) https://doi.org/10.1117/12.582649

KEYWORDS: Silicon, Oxides, Resistance, Gold, Carbon, Atomic force microscopy, Electrodes, Scanning probe microscopy, Interfaces, Oxidation

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Proceedings Article | 23 February 2005 Paper

AFM-based micro/nanoscale lithography of poly(dimethylsiloxane): stick-slip on softpolymer

Jolanta Watson, Sverre Myhra, Christopher Brown, Gregory Watson

Proceedings Volume 5650, (2005) https://doi.org/10.1117/12.582650

KEYWORDS: Polymers, Lithography, Silicon, Atomic force microscopy, Scanners, Microtechnology, Optical coatings, Optical amplifiers, Connectors, Scanning probe microscopy

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Proceedings Article | 16 February 2005 Paper

AFM analysis of the formation of DNA aggregates on polymeric biochips

Prashant Sawant, Gregory Watson, Sverre Myhra, Dan Nicolau

Proceedings Volume 5651, (2005) https://doi.org/10.1117/12.584142

KEYWORDS: Fractal analysis, Polymers, Chemical analysis, Atomic force microscopy, Glasses, Plasma, Photomicroscopy, Biological research, Statistical analysis, Chemistry

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Proceedings Article | 1 July 2004 Paper

An AFM study of the hierarchical DNA immobilization/hybridization processes on surfaces

Prashant Sawant, Gregory Watson, Dan Nicolau

Proceedings Volume 5322, (2004) https://doi.org/10.1117/12.543444

KEYWORDS: Fractal analysis, Atomic force microscopy, Glasses, Statistical analysis, Polymers, Silicon, Sodium, 3D image processing, Solids, Surface roughness

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Proceedings Article | 14 November 2002 Paper

Interactions of poly(amino acids) in aqueous solution with charged model surfaces: analysis by colloidal probe

Gregory Watson, Jolanta Blach, Colm Cahill, Dan Nicolau, Duy Pham, Jonathan Wright, Sverre Myhra

Proceedings Volume 4937, (2002) https://doi.org/10.1117/12.471941

KEYWORDS: Silica, Interfaces, Optical spheres, Adsorption, Atomic force microscopy, Solids, Chemistry, Spherical lenses, Systems modeling, Proteins

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Proceedings Article | 14 November 2002 Paper

Nanolithography of polymer surfaces by atomic force microscopy

Jolanta Blach, Gregory Watson, Chris Brown, Duy Pham, Jonathan Wright, Dan Nicolau, Sverre Myhra

Proceedings Volume 4937, (2002) https://doi.org/10.1117/12.469736

KEYWORDS: Polymers, Atomic force microscopy, Lithography, Chemistry, Polymer thin films, Biosensors, Raster graphics, Atomic force microscope, Thin films, Terbium

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Proceedings Article | 14 November 2002 Paper

UV-patterned polymide surfaces: characterization by atomic force microscopy (AFM)

Jolanta Blach, Gregory Watson, Christopher Brown, Takeharu Suzuki, Sverre Myhra

Proceedings Volume 4937, (2002) https://doi.org/10.1117/12.469734

KEYWORDS: Chemistry, Silicon, Atomic force microscopy, Capillaries, Ultraviolet radiation, Polymers, Adhesives, Interfaces, Optical lithography, Gold

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Proceedings Article | 13 November 2002 Paper

Characterization of cuticular nanostructures on surfaces of insects by atomic force microscopy: mining evolution for smart structures

Gregory Watson, Jolanta Blach

Proceedings Volume 4934, (2002) https://doi.org/10.1117/12.469733

KEYWORDS: Atomic force microscopy, Nipple, Smart structures, Eye, Nanostructures, 3D image processing, Mining, Visualization, Camouflage, Antireflective coatings

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Proceedings Article | 13 November 2002 Paper

Nanoscale spatially resolved simultaneous measurement of in-plane and out-of-plane force components on surfaces: a novel operational mode in atomic force microscopy

Gregory Watson, Bradley Dinte, Jolanta Blach, Sverre Myhra

Proceedings Volume 4934, (2002) https://doi.org/10.1117/12.469732

KEYWORDS: Atomic force microscopy, Tellurium, Calibration, Crystals, Signal detection, Sensors, Scanners, Mica, Interfaces, Microscopy

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Proceedings Article | 21 June 2002 Paper

Radiation patterning of P(tBuMA-co-MMA) thin films for biosensor applications: characterization by scanning probe microscopy

Gregory Watson, Jolanta Blach, Dan Nicolau, Sverre Myhra

Proceedings Volume 4626, (2002) https://doi.org/10.1117/12.472063

KEYWORDS: Chemistry, Polymers, Atomic force microscopy, Thin films, Biosensors, Optical lithography, Oxides, Scanning probe microscopy, Adhesives, Chemical elements

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Showing 5 of 14 publications

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