NANOMES 692

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NANO/MES 692

• Printed Electronics
• Materials and Processes

http//sdmines.sdsmt.edu/sdsmt/directory/courses/2
009sp/mes692M081 William.cross_at_sdsmt.edu
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Printed Electronics

• Integrates
• Printing
• Electronics
• Materials Science
• Chemistry and Polymer Chemistru
• Functionality
• Processability

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Printed Electronics

• Ink
• Nanoparticles
• Solvent
• Substrate
• Flexible
• Stiff
• Writing
• Interaction
• Wetting
• Adhesion

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Direct Write Technologies

• General Definition
• Any technique or process capable of depositing,
  dispensing, or processing (including subtractive)
  different types of materials over various
  surfaces following a preset pattern or layout
  (Pique Chrisey 2002)
• Manufacturing processes characterized by the use
  of computer-generated patterns and shapes for
  direct fabrication without part-specific tooling

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Direct Write Capabilities
Maskless, Mesoscale, Material Deposition (M3D)
(Optomec, Inc.)
2831 Ink Jet Printer (Dimatix, Inc.)
Syringe Dispensing Printer (nScrypt, Inc.)
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Ink-Jet

• Operation is similar to a circuit board milling
  machine with the bit replaced by a dispensing
  head.

Tony Amert MS Defense
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Ink-Jet

• Advantages
• Digital
• High speed
• Head technology is well established, single and
  multi-nozzle formatted
• Many machine vendors

• Disadvantages
• Limited and low material viscosity range
• Particle filler issues (clogging)
• Conformality difficult

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nScrypt

• Essentially a computer controlled pen.
• Contact process but maps the surface before
  printing.
• Includes a laser and an ink-jet deposition head.

Tony Amert MS Defense
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nScrypt

• Advantages
• Digital
• Conformal
• Large material cross-section/high solid loadings
• Wide material viscosity range
• Head technology is well established
• Tool vendors in place

• Disadvantages
• Limited resolution (often 150-200 microns)
• Single head/nozzle
• Marginal speed

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Maskless, Mesoscale, Material Deposition (M3D)
System

• Prototyping system produced by Optomec Inc.
• Aerosol Jet Deposition
• Ultrasonic Atomization
• Pneumatic Atomization

Tony Amert MS Defense
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M3D

• Advantages
• Conformality possible
• High resolution capability (25 micron)
• Wider material viscosity range (vs. Ink-jet)
• Variety of tip/nozzle dispensing sizes

• Disadvantages
• Head technology less advanced
• Single tip/nozzle
• Not many vendors of compatible inks

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Direct Write Capabilities

• Non-contact process, features lt 25 µm (80 µm
  common)
• Commercial printing method
• Ink (150 cP) less than 1 µm particles,
  Dispersion.
• NOT many ink vendors

Ink-Jet

• Contact printing process capable of lt 50 µm
  feature sizes
• Can print on conformal (non-planar) surfaces
• Thick paste (1100,000 cP) can print widest
  range
• Single tip may limit throughput
• NOT many ink vendors

nScrypt

• Non-contact Aerosol Jet Deposition System
• Feature size lt 25 µm (5 µm thick)
• Ink (11,000 cP) metals, conductors,
  insulators, ferrites, polymers, enzymes,
  proteins, and nucleic acid
• Wide range of tip sizes
• Single tip may limit throughput
• NOT many ink vendors

M3D
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Nanoparticle Manufacture

• Clear need for inks
• Particles
• Provide needed property
• Size
• Shape
• Solvent
• Particle dispersion
• Substrate interaction
• Volatility
• Conductive, semi-conductive, non-conductive

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Nanoparticle Manufacture
A few Å

• Ions in solution
• Nucleate
• Homogeneous
• Heterogeneous
• Growth
• Capping
• Adsorpton
• End

-
-

A few nm
A few 10s of nm
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Ions in Solution

• Thermodynamics
• Equilibrium
• Activity
• Solubility

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Solution Thermodynamics

• Internal Energy, U
• State function
• Mechanical work (dWmech-pdV)
• Entropy (dQTdS)
• dUmatter
• charge transfer
• (dUmatter?dq)
• electric field
• (dUmatter-EdP)
• magnetic field
• (dUmatter-BdM)
• interfacial energy
• (dUmatter?dA)

Open system
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Solution Thermodynamics
I
III
II
In each phase
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Solution Thermodynamics

• Helmholtz Free Energy, H or F
• useful work obtainable from a closed
  thermodynamic system at a constant temperature
  and volume.
• FU-TS
• dFdU-TdS (constant temperature)
• dFdQ-pdV-TdexchS-TdirrS
• Constant volume pdV0 closed system dQTdexchS
• dF-TdirrS0
• Chemical reaction, dF-SmkNk-TdirrS0

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Solution Thermodynamics

• Gibbs Free Energy, G
• the Gibbs free energy ?G equals the work
  exchanged by the system with its surroundings,
  less the work of the pressure forces, during a
  reversible transformation of the system from the
  same initial state to the same final state
• GUpV-TSH-TS HUpV heat released at constant
  pressure
• dGVdp-SdT SmkdNk at constant p and T
  dGSmkdNk
• dG/NdGm SmkdNk /N SmkdXk
• XkNk/N mole fraction

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Solution Thermodynamics

• Entropy, S, is a measure of the unavailability of
  a systems energy to do work. It is a measure of
  the disorder of molecules in a system, and is
  related to systems changes occurring
  unexpectedly. Spontaneous changes in isolated
  systems occur with an increase in entropy.
  Unexpected changes tend to average out
  differences in temperature, pressure, density,
  and chemical potential that may exist in a
  system, and entropy is thus a measure of how
  great the unexpected changes are.

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Solution Thermodynamics

• Reversible process
• a process that can be "reversed" by means of
  infinitesimal changes in some property of the
  system without loss or dissipation of energy
• Only really true in the limit of infinite
  slowness
• Irreversible process
• interacting molecules change thermodynamic state
  a certain amount of "transformation energy" will
  be used. During this transformation, there will
  be a certain amount of heat energy loss or
  dissipation due to intermolecular friction and
  collisions energy that will not be recoverable
  if the process is reversed.

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Solution Thermodynamics
Isolated system no transfer through boundary
dexchS
dirrS0
dexchS0
dirrS
Closed system only energy transfer through
boundary
dexchSdQ/T
dirrS0
Open system energy and matter transfer through
boundary
dirrS0
True for all subsystems
dirrS0
dexchSdQ/T(dexchS)matter
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Solution Thermodynamics

• Equilibrium

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Solution Thermodynamics

• Chemical potential, m
• the amount by which the energy of the system
  would change if an additional particle were
  introduced, with the entropy and volume held
  fixed. If a system contains more than one species
  of particle, there is a separate chemical
  potential associated with each species, defined
  as the change in energy when the number of
  particles of that species is increased by one.
• SdT - Vdp Ndm 0 SmdT Vmdp dm
• m(p,T) m(p0,T)?Vm(p,T)dpgt mkmk0RTlnak

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Solution Thermodynamics

• Activity, a
• activity is a measure of the effective
  concentration of a species in a mixture. The
  activity of pure substances in condensed phases
  (solid or liquids) is normally taken as unity.
  Activity depends on temperature, pressure and
  composition of the mixture, among other things.
  For gases, the effective partial pressure is
  usually referred to as fugacity.
• The difference between activity and other
  measures of composition arises because molecules
  in non-ideal gases or solutions interact with
  each other, either to attract or to repel each
  other. The activity of an ion is particularly
  influenced by its surroundings.

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Solution Thermodynamics
C0 is the standard concentration 1 mol/l
m0 is the standard molality 1 mol/kg
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Solution Thermodynamics

• Chemical Reactions
• Precipitation of solid nanoparticles
• Activity of precursors in solution important
• Affinity
• State variable that is driving force for chemical
  reactions
• XY2Z Amxmy-2mz
• -dNx-dNydNz/2d? (change in extent of reaction)

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Solution Thermodynamics
XY2Z
dUTdS-pdVSmkNk
dS(dUpdVSmkdNk)/T
or
SmkdNk mXdNx mydNy mzdNz (mX my-2mz)d?Ad?
dS(dUpdV)/TdirxnS
dirxnS(Ad?)/Tgt0
Equilibrium A0
In general reaction naAnbBndDneE
Nigt0
nilt0
AS-nimi-dG
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Solution Thermodynamics
XY2Z
(mX my-2mz)A0
mkmk0RTlnak
mX my2mz
mx0(T)RTlnax,eq my0(T)RTlnay,eq2mz0(T)RTlnaz
,eq
SnimiDGrxnDG0RTlnp(niai)
mi0DGf,i0