Carbon NanotubesCarbon Nanotubes

Carbon Nanotubes were discovered Carbon Nanotubes were discovered by Mr. Sumio Ijima in the year 1991by Mr. Sumio Ijima in the year 1991

IntroductionIntroduction

As there name suggests, these are cylindrical in As there name suggests, these are cylindrical in shape and their diameter is around 1 nm which shape and their diameter is around 1 nm which is approximately 50,000 smaller compared to the is approximately 50,000 smaller compared to the diameter of a human hair.diameter of a human hair.

These belong to the structural family of These belong to the structural family of fullerenes.fullerenes.

These are made up of a single layered sheet of These are made up of a single layered sheet of graphite known as graphene. Hence, they are graphite known as graphene. Hence, they are allotropes of carbon.allotropes of carbon.

Types Of Carbon NanotubesTypes Of Carbon Nanotubes

Single Walled Single Walled Nanotubes ~ Nanotubes ~ SWNTSWNT

Multi Walled Multi Walled Nanotubes ~ Nanotubes ~ MWNTMWNT

SWNTSWNT

These are made of a single sheet of These are made of a single sheet of graphene.graphene.

They can be classified into three types They can be classified into three types depending on the orientation of the C – depending on the orientation of the C – hexagons in the tube……Zig Zag hexagons in the tube……Zig Zag Nanotubes, Armchair Nanotubes & Chiral Nanotubes, Armchair Nanotubes & Chiral Nanotubes.Nanotubes.

Zig Zag NanotubesZig Zag Nanotubes

In these type of nanotubes the hexagons In these type of nanotubes the hexagons are so arranged that their apex is parallel are so arranged that their apex is parallel to the axis of the tube.to the axis of the tube.

These are optically inactive.These are optically inactive.

Arm Chair NanotubesArm Chair Nanotubes

In these type of nanotubes the hexagons In these type of nanotubes the hexagons are so arranged that their apex is are so arranged that their apex is perpendicular to the axis of the tube.perpendicular to the axis of the tube.

These are optically inactive.These are optically inactive.

Chiral NanotubesChiral Nanotubes

Arranging the hexagons in any other way Arranging the hexagons in any other way other than that in the zig zag or arm chair other than that in the zig zag or arm chair models gives structures to nanotubes models gives structures to nanotubes which are chiral i.e. they have mirror which are chiral i.e. they have mirror images and can’t be superimposed.images and can’t be superimposed.

These are optically active.These are optically active.

SWNT ~ CompilationSWNT ~ Compilation

MWNTMWNT

These are prepared from either a single or These are prepared from either a single or many graphene sheets.many graphene sheets.

There structures can be postulated by the There structures can be postulated by the two models ~ Russian Doll Model & The two models ~ Russian Doll Model & The Parchment Model. Parchment Model.

Russian Doll ModelRussian Doll Model

In this model graphene sheets are In this model graphene sheets are arranged in concentric cylinders.arranged in concentric cylinders.

The Parchment ModelThe Parchment Model

In this model a single graphene sheet is In this model a single graphene sheet is rolled over itself. It looks like a scroll.rolled over itself. It looks like a scroll.

Properties Of Carbon NanotubesProperties Of Carbon Nanotubes

They possess the highest strength to weight They possess the highest strength to weight ratio amongst all known materials.ratio amongst all known materials.

They are harder than steel but smaller than a They are harder than steel but smaller than a single human hair.single human hair.

They are conductors of heat and electricity. They are conductors of heat and electricity. They can be used to trap heat.They can be used to trap heat.

Their electrical conductivity can be manipulated Their electrical conductivity can be manipulated to a higher scale of variance depending upon to a higher scale of variance depending upon molecules that combine with the carbon atoms.molecules that combine with the carbon atoms.

Applications Of Carbon NanotubesApplications Of Carbon Nanotubes

energy-storing electronic textiles energy-storing electronic textiles artificial muscles artificial muscles catalyst supports catalyst supports nearly impenetrable bullet-proof vests and body armor nearly impenetrable bullet-proof vests and body armor hydrogen, ammonia, humidity, and pollution sensors hydrogen, ammonia, humidity, and pollution sensors DNA biosensors, immunosensors, and health monitoring DNA biosensors, immunosensors, and health monitoring

sensors sensors biological sensors, for applications such as: biological sensors, for applications such as:

       monitoring hydrogen levels in premature babies        monitoring hydrogen levels in premature babies        quality control in food production plants        quality control in food production plants        pollution monitoring in truck and auto engines        pollution monitoring in truck and auto engines

biomedical sensors (small enough to pass through cells, biomedical sensors (small enough to pass through cells, and not trigger immune response) and not trigger immune response)

Applications Of Carbon NanotubesApplications Of Carbon Nanotubes

biological and chemical warfare agent sensors biological and chemical warfare agent sensors semiconductor devices semiconductor devices field-effect transistors (FET) field-effect transistors (FET) field emission displays (FED) for large-area TV's field emission displays (FED) for large-area TV's advanced generation high resolution flat panel displays advanced generation high resolution flat panel displays light emission devices light emission devices silicon etching silicon etching molecular electronics molecular electronics heat-conducting applications heat-conducting applications supercapacitors supercapacitors advanced reinforced composites advanced reinforced composites conductive adhesives, coatings, caulks, paints, and conductive adhesives, coatings, caulks, paints, and

sealants sealants

Applications Of Carbon NanotubesApplications Of Carbon Nanotubes

advanced atomic force microscopes advanced atomic force microscopes nano-motors and mechanisms nano-motors and mechanisms nanoscale tools, such as tweezers nanoscale tools, such as tweezers sports equipment (tennis racquets, yacht masts, fishing sports equipment (tennis racquets, yacht masts, fishing

rods, etc.) rods, etc.) earthquake-resistant buildings or towers earthquake-resistant buildings or towers frictionless, low-wear bearings and other nanoscale frictionless, low-wear bearings and other nanoscale

components components solid lubricant or as additives solid lubricant or as additives as heat sinksas heat sinks to develop lightweight spacecraft parts to develop lightweight spacecraft parts

Nanowires NWNanowires NW

Introduction Introduction

A nanowire is a wire of dimensions of the A nanowire is a wire of dimensions of the order of a nanometer.order of a nanometer.

At these scales, quantum mechanical At these scales, quantum mechanical effects are important — hence such wires effects are important — hence such wires are also known as "quantum wires". are also known as "quantum wires".

Types Of NanowiresTypes Of Nanowires

Metallic ~ Ni, Pt ,AuMetallic ~ Ni, Pt ,AuSemi Conducting ~ InP, Si, GaNSemi Conducting ~ InP, Si, GaN Insulating ~ SiO2, TiO2Insulating ~ SiO2, TiO2

Properties And Applications Of Properties And Applications Of NanowiresNanowires

Semi Conducting Nanowires can be used Semi Conducting Nanowires can be used to make transistors which can be used as to make transistors which can be used as switches or as amplifiers.switches or as amplifiers.

NW are ballistic conductors as the NW are ballistic conductors as the electrons can flow continuously inside electrons can flow continuously inside them which eliminates the evolution of them which eliminates the evolution of heat and wastage of energy.heat and wastage of energy.

They can be used as magnetic information They can be used as magnetic information storage mediums.storage mediums.

Properties And Applications Of Properties And Applications Of NanowiresNanowires

They are used in energy conversion They are used in energy conversion devices.devices.

They can be used to construct logic gates.They can be used to construct logic gates.Nanowire arrays are used in Field Nanowire arrays are used in Field

Emission Devices. Emission Devices. Their optical properties are intriguing Their optical properties are intriguing

which result in various applications.which result in various applications.Alike carbon nanotubes their electrical Alike carbon nanotubes their electrical

resistance can be manipulated. resistance can be manipulated.