Seminar SN
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Transcript of Seminar SN
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NANOSCALE COATING
PRESENTING BYAKHIL VKREG NO - 13021900
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2 INTRODUCTION
• Advances in the methods for producing and researching nanoscale materials have enhanced the capabilities of surface coatings.
• Applications of nanoscale surface coatings are seen in areas such as biocides, matting agents, and physical properties.
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• Since this is a new and developing field, nanoscale surface coating techniques borrow from nanolithography, while new ways to create nano patterned and nanostructured surfaces are continuing to be developed.
• Lithographic etching techniques are often used to create nanoscale patterns on surfaces
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NANO SCALE COATING ?
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5• Nanoscale surface coatings are surface coatings engineered on the
nanoscale, a sub 100-nanometer (10-9 meter) length scale, to provide further functional applications
• Surface coatings are mixtures of film-forming materials plus pigments, solvents, and other additives,
• Advances in the methods for producing and researching nanoscale materials have enhanced the capabilities of surface coatings.
• Applications of nanoscale surface coatings are seen in areas such as heat transfer, biocides, matting agents, and physical properties.
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7 (CHF) phenomenon ?
• Two phase heat transfer is highly efficient mode of heat
dissipation but its implementation can be restricted as a
result of the critical heat flux (CHF) phenomenon.
CRITICAL HEAT FLUX
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8• CHF essentially limits the heat flux dissipation potential of two
phase (boiling) heat transfer and exceeding this CHF limit may
result in component damage.
• The increasing amount of research into nanofluid boiling has
provided a better understanding into the effects of nanofluids on
boiling performance and specifically their effect on boiling heat
transfer (BHT) and critical heat flux (CHF).
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9 NANOSTRUCTURED SURFACE FABRICATION TECHNIQUES
LITHOGRAPHY BASED FABRICATION
NANOCOATINGS BY POOL BOILING HEAT
TRANSFER
NANOPOROUS MATERIALS
NANOTUBES AND NANOWIRES
NANOPARTICLE ASSEMBLY
NANOPARTICLE MASK – ETCHING
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10LITHOGRAPHY BASED FABRICATION
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11• Semiconductors like Gallium Phosphate and Gallium Arsenic are
more reliable surfaces than gold.
• Developments in manufacturing include work by The National Institute of Advanced Industrial Science and Technology (AIST) of Japan.
• They managed to use 172 nm vacuum Ultra Violet light to etch nanowells and chemically activate the exposed polymer substrate surfaces.
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12 DIP PEN NANOLITHOGRAPHY(DPN)
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13 ADVANTAGES
1-10 micro-metre feature resolution No multiplexed depositions Each molecular ink is limited to its corresponding
substrate Less restrictive ink/surface requirements Direct deposition of high viscosity materials Scalable
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Atomic force microscopy (AFM) image (3D rendering) of 160-nm-high nanocolumns created on a PMMA substrate by colloidal lithography
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15 APPLICATIONS
Biosensor Functionalization Nanoscale Sensor Fabrication Nanoscale Protein Chips Subcellular drug delivery Cell adhesion
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16 NANOCOATINGS BY POOL BOILING HEAT TRANSFER
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• According to our current understanding, heat transfer during pool boiling is associated with three main mechanisms:
1. transient conduction,2. microlayer evaporation,3. microconvection.
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• Pool boiling is an efficient mechanism for heat transfer due to the associated phase change process.
• Two phase heat transfer is highly efficient mode of heat dissipation but its implementation can be restricted as a result of the critical heat flux (CHF) phenomenon.
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19POOL BOILING
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MECHANISM OF NANOPARTICLE COATING THROUGH POOL BOILING
Optical (left) and SEM (right) images of developed nanocoatings in 0.025 g/l water-based nanofluid for 15 min (top) and 120 min (bottom) at 1000 kW/m2
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21 APPLICATIONS
The wetting characteristics of a substrate can be varied.
Heat transfer coefficient can be increased.
Thickness of the nanocoatings can be easily varied.
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22 • NANOPOROUS MATERIAL
• SILICON NANOWIRE
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23 • Image of a biofilm containing bacteria and others
• Biofilm-induced corrosion and blocking of heat exchanger tubes
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24 APPLICATIONS OF NANOSCALE SURFACE COATINGS
Heat transfer
QED cooling of electronics and turbine blades
Biocides
Physical properties
Improving biocompatibility of implantable metals by
nanoscale modification of surfaces
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CONCLUSION
• The wetting characteristics of a substrate can be varied by proper
selection of the process and materials for creating nanostructured
surfaces.
• For hydrophilic nanostructured surfaces, the pool boiling heat
transfer coefficient as well as CHF values increase over the base untreated surface
• .• The increase could be substantial, up to 100 percent or more
depending on the type of the coating, coating height and its structure.
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?
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THANK YOU
BYAKHIL VKDEPT OF MECH