Basics of Nanotechnology

1. NANOTECHNOLOGY

2. Whatis
Nanotechnology?
• Nanotechnology, shortenedto “nanotech”, is the study of the controlling of matter on
an atomic and molecular scale. Generallynanotechnology deals with structuressized
between 1 to 100nanometerin at least one dimension and involve developing
materials or devices within that size.
• A basic definition: Nanotechnology is theengineeringof functional systems at the
molecularscale. This covers both currentworkand concepts that aremore advanced.
• Inits original sense, ‘nanotechnology’refers to the projected ability to construct items
from the bottom up, using techniquesand tools being developed today to make
complete, high performance products.
• Nanotechnology, in its traditional sense, means building things from the bottom up,
with atomic precision.

3. How
Nanotechnologyworks ?

5. TheWorld of
Nanotech
Expertssometimesdisagreeabout what constitutesthe
nanoscale,but ingeneral,youcan think of
nanotechnologydealingwith anythingmeasuringbetween
1 and100 nm.Largerthan that isthe microscale,and
smallerthanthat isthe atomicscale.
Nanotechnologyisrapidlybecomingan interdisciplinary
field.Biologists,chemists,physicistsand engineersareall
involvedinthestudy ofsubstancesat the nanoscale.Dr.
Störmerhopes that the differentdisciplinesdevelopa
commonlanguageand communicatewith oneanother.
Onlythen, hesays,can weeffectivelyteach nanoscience
sinceyou can't understandthe worldof nanotechnology
without asolidbackground inmultiplesciences.
Anengineerpreparesa silicon waferin an earlystageof
microchip production.

6. Atthenanoscale,objects areso small thatwe can'tsee them --even withalight microscope. Nanoscientists haveto
use tools like scanningtunnelingmicroscopes or atomicforce microscopes to observe anythingatthe
nanoscale. Scanningtunnelingmicroscopes use aweakelectric currentto probe thescannedmaterial.Atomic
force microscopes scansurfaceswithanincredibly fine tip. Bothmicroscopes send datato a computer, which
canassemble theinformation and project it graphicallyonto amonitor
It’s a smallworld after all

7. Synthesis of nanoparticles
• Nanoparticles may be created using several methods. Some of them may occur in nature as
well. The methods of creation include attrition and pyrolysis. While some methods are bottoms
up, some are called top down. Top down methods involve braking the larger materials into
nanoparticles.
Nanoparticle Synthesis
Top-Down via Bottom-Up via
Attrition / Milling Pyrolysis
Inert gas condensation
Solvothermal reaction
Sol-Gel fabrication
Structured media

8. Attrition
• Attrition methods includemethods by which macro ormicro scale
particles are groundin a ball mill, a planetaryball mill, or othersize
reducingmechanism. Theresulting particles areair classified to
recover nanoparticles.
• Involves mechanicalthermal cycles
• Yields
– broadsizedistribution(10-1000 nm)
– variedparticleshapeorgeometry
– impurities
• Application
– Nanocomposites
– Nano-grainedbulk materials

9. Bottom up methods
• These arefurther classified according tophases:
• Gas (Vapor) Phase Fabrication: Pyrolysis, Inert GasCondensation
• Liquid Phase Fabrication: Solvothermal Reaction, Sol-gel,Micellar Structured Media

10. pyrolysis
• Inpyrolysis, a vaporous precursor (liquid or gas) is forced througha hole or opening at high pressure and
burned.Theresulting solid is air classified to recover oxide particles from by-product gases. Pyrolysis often
results in aggregates and agglomerates ratherthan singleton primaryparticles.
• Instead of gas, thermalplasma can also deliver the energynecessary to causeevaporation of small micrometer
size particles. Thethermalplasma temperaturesare in the order of 10,000K, so that solid powder easily
evaporates. Nanoparticles are formedupon cooling while exiting the plasma region. Examples of plasma used
includedc plasma jet, dc arcplasma andradio frequency(RF) induction plasmas.
• For example, silica sand can bevaporized with anarc plasma at atmospheric pressure. Theresulting mixtureof
plasma gas and silica vapour can be rapidly cooled by quenchingwith oxygen, thus ensuringthe quality of the
fumedsilica produced.
• Theadvantages of vapor phase pyrolysis includeit being a simple process, cost effective, a continuous
operation with high yield.

11. Spray pyrolysis

12. • Theliquidphase fabricationentailsa wet chemistryroute.
• Methods are:
• SolvothermalMethods(e.g.hydrothermal)
• Sol-GelMethods
• SynthesisinStructure Media(e.g., microemulsion)
• Effectivenessof SolvothermalMethods and Sol-gelmethods demands a simpleprocess,lowcost,continuous operationand high
yield.
Precursors are dissolved in hot solvents (e.g., n-butylalcohol) and solvent other than water can provide milderand
friendlier reaction conditions If the solvent is water then theprocess is referred to as hydrothermalmethod.
Liquid phase synthesis
Solvo-thermal process

13. Sol-gel process
• The sol-gel process is a wet-chemical technique (also known as chemical solution
deposition) widely used recently in the fields of materials science and ceramic
engineering.
• Steps include:
– Formationofstable sol solution
– Gelationvia apolycondensationorpolyesterificationreaction
– Gel aging intoa solid mass.This causescontractionof thegel network,also phase
transformationsandOstwaldripening.
– Dryingofthe gel toremove liquidphases.Thiscanlead tofundamentalchangesin the
structureofthe gel.
– Dehydrationattemperaturesashigh as8000degree C, usedto removeM-OH groupsfor
stabilizingthegel, i.e., toprotectit fromrehydration.
– Densificationanddecompositionofthe gels athigh temperatures(T> 8000degree C), i.e., to
collapsetheporesin thegel networkandtodrive outremaining organiccontaminants

14. Sol-gel method

15. Nanowiresand Carbon Nanotubes
Currently,scientistsfindtwo nano-size structuresofparticular
interest:nanowiresandcarbonnanotubes.Nanowiresarewires
withaverysmalldiameter,sometimesassmallas1 nanometer.
Scientistshope tousethem to buildtinytransistorsforcomputer
chipsandotherelectronicdevices.In thelastcouple ofyears,carbon
nanotubeshaveovershadowednanowires.We'restilllearning
about thesestructures,but what we'velearnedsofarisveryexciting.
A carbonnanotube isa nano-sizecylinderofcarbonatoms. Imaginea
sheetofcarbonatoms,whichwould looklike asheetofhexagons. If
yourollthat sheetintoa tube,you'dhave acarbonnanotube.
Carbonnanotube propertiesdependonhow yourollthe sheet.In
otherwords,eventhoughallcarbonnanotubesaremade ofcarbon,
theycanbeverydifferentfrom oneanotherbasedonhowyoualign
the individualatoms.

16. What'sthedifference betweengraphite anddiamonds?
Bothmaterialsaremadeofcarbon, butbothhavevastlydifferentproperties.Graphiteis
soft;diamondsarehard.Graphiteconductselectricity,butdiamondsareinsulators
andcan'tconductelectricity.Graphiteisopaque;diamondsareusuallytransparent.
Graphiteanddiamondshavethesepropertiesbecauseofthewaythecarbonatoms
bondtogetheratthe nanoscale.
GRAPHITE DIAMONDS
VS.

17. Nanomachines
• If molecular models really moved while revealed in the animations
underneath, that theycouldn't work. Do not pin the consequence
on your simulation or perhaps the look, though. The issue is the
regular way to render videoclipsupport frames makes a
stroboscopic impression regarding jerky movement. Atoms
generally vibratecountless times for each body,yetregular frames
catch the positioning of each and everyatom with a one quick,just
as ifnoticed with the displayof your stroboscope. That creates the
actual optical illusion which the atoms most vibrateat the shape
charge, that istoo towards the regularity in the machine's
transferring components. This providesyou with this misconception
how the deviceparts are going on just about arctic pace,just like
this paceassociated with appear.From that will pace,even though
your machine provedhelpful, chaffing would beintolerable. MarkIII(k) Planetary Gear

18. And hereisyourSRG-Ic, virtuallyanyparallel-shaftswiftnessreducermerchandiseputtogetherbyQuantities
Sims.This beenfounddesignedandinadditionsimulatedthoroughlyapplyingNanoEngineer-1.Thisspecific
assemblageısknownforapinionphysicalobjects,someformofeffectobjects,aswellasasiliconcarbide
defendinghavinganumberofutilizedbushings
SRG-Ic
SRG-II
ThisistheSRG-II.IthadbeenpatternedbesidessimulatedjustmakinguseofNanoEngineer-1
(Alphadog6).ThegoaloftheactualSRG-IIappearedbecomingtoproduceaeffectivenanoscale
itemswhichincludes anykindofpropertyalongwithlongconnectionshafts.
SRG-III
ThisissometimesaSRG-III.Thatbeenfoundmodeledplussimulatedentirelyimplementing
NanoEngineer-1.AbrandnewcrossbreedwhileusingSRG-ItogetherwithSRG-II, oahuisthe2nd
molecularitemscoach previouslymeant.Acquiring15, 342atoms,yourSRG-IIIwillbetheupcoming
biggestnanomechanicalsystemreallypatternedinsideatomicaspect.

19. Nanotechnology in Medicine
• – Researchers in medicines are developing customized nanoparticles as the size of
molecules that can directly deliver drugs to the diseased cells in the body. When this
method is perfected than it will reduce the damaged treatment such as chemotherapy does
to the patient’s healthy cells.

20. Nanotechnology in Electronics
• Nanotechnology increases the
capabilities of electronics devices
while reducingtheir weight and power
consumption.
• Improves display screens on
electronics devices.
• Increasingthe density of memory
chips
• Reducing the size of transistors used in
integrated circuits

21. Integrated circuits