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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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THANK YOU

BYAKHIL VKDEPT OF MECH