Experiments

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Experiments

• Synthesis of Nano Particles and Encapsulation
• Synthesis of Hexagonal Mesoporous Silica
  Carbon
• Synthesis of Organic and Carbon Xerogels
• Synthesis of Silver NanoWires

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Demostration Experiments

• Sol-Gel Synthesis via TMOS
• Sol-Gel Synthysis using Sodium silicate better
  known as furnace cement.
• Ultrasonic synthesis of TMOS

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SOL-GEL SCIENCE
Mix the reactives

• Gelification
• Aging
• Soaking

Hydrolysis and Condesation reactions take place
Sol
Gelification
Aging
Drying
Gel
Gel
Aerogel
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Gelification
Mix reactives
Hydrolysis and Condesation reactions take place
Sol
Gelification
Aging
Gel
Gel
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Designing Nanomaterials
First Step
Silica Solution Precursor Tetraetilortosilicate
Si(OCH2CH3)4 Solvent Ethanol
Catalyst OxalicAcid
Modifications
pH (final product) Temperature (crystal
phase) Precursor (Type of material) Time
(Strength) etc
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(I) SOL-GEL SYNTHESIS OF AEROGELS   Aerogels
are a unique, nanostrutured material derived
from gels. Gels are a novel class of material
exhibiting solid-like behavior although
consisting predominantly of a liquid phase. Their
solidity derives from a continuous
interpenetrating framework that, in essence, acts
like a molecular scaffold extending throughout
the liquid. This perspective of a gel as a
molecular web in a liquid has found many
industrial applications.     Fig
ure 1 A silicon oxide low density aerogel

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Gelification
Mix reactives
Hydrolysis and Condesation reactions take place
Sol
Gelification
Aging
Gel
Gel
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Synthesis of Nano Particles and Encapsulation

• Synthsis of Tiatnium and silica nanoparticles
• Sol-Gel Encapsulation
• Jorge Arias

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Encapsulated Dendrimer

• The following figure shows mono dispersed
  Starburst PAMAM polyamidoamine dendrimers
  encapsulated in a sol-gel matrix of silica at 25
  wt. . Surface area analysis shows the material
  surface area was 617 m2/g. The dark spheres in
  Figure 1 dispersed throughout the silica matrix
  show diameters similar to their hydrodynamic
  values for this dendrimer in solution.

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PAMMA Dendrimer
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Sol-Gel Encapsulated Dendrimer
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Gelification
Mix reactives
Hydrolysis and Condesation reactions take place
Sol
Gelification
Aging
Gel
Gel
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Synthesis of Hexagonal Mesoporous Silica Carbon

• This lab couples the hydrolysis and condensation
  of TEOS or other silica sources with Structure
  directing agents such as surfactants or polymers
  .
• It also uses the final silica mesoporous material
  as a template to synthesize a high surface area,
  hexagonal pure carbon material.
• Phong Nugyen, instructor

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   MESOPOROUS ZEOLITE-TYPE MATERIALS
The uniqueness of surfactant templated materials
allows a variety of metal oxides to be formed
with uniform honeycomb structure and surface area
approaching 1000 m2/g. Surfactant templated
materials have already been synthesized by the
authors These materials were synthesized with Mg,
Cr, Ru, Pt, and Co doped in the MCM-41 silica
oxide.
FIGURE 7. TEM of MCM-41 synthesized by the author
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Synthesis of large Scale Mesoporous Substrates
(A) 60Å, (B) 89 Å, (C)
200 Å, (D) 260 Å.
FIGURE 8 TEM of
mesoporous silica with different average pores
sizes
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Synthesis of Organic and Carbon Xerogels

• Resorcinol is a molecule that much like TEOS can
  undergo hydrolysis and condensation reaction to
  form a gel structure that can be dry as a xerogel
  or aerogel.
• This gel can be further transformed in to a high
  surface area carbon material. It gives the
  highest capacitance per unit volume .
• Laurent Moch will demonstrate.

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Synthesis of Silver NanoWires

• Particles are templated into a cylindrical shape
  using a polymer.
• Martina Dreyer.

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Synthesis of Silver NanoWires
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NANOSTRUCTURED ANODIZED ALUMINUM
Anodized aluminum is an ideal substrate in that
it possesses vertical pores perpendicular to its
surface.These nanopores are formed by
electrochemical etching and pore diameter can be
precisely controlled from 300 nm down to 2nm.

    Figure 5 Anodized Alunminum
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Figure 6 Diagram for using anodized aluminum to
synthesize carbon nanotubes
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Reactors CVD Synthesis of SWNTs

• Two parallel thermal reactors capable have
  already been constructed and tested,
• These carbon nanotube reactors can operate from
  100 torr to above atmospheric
• The reactors temperature is computer controlled
  and may be ramped.
• The reactors are set up to run either in parallel
  or separately
• One of the reactors can handle large substrates
  such as silicon wafers up to 6 inches. 

FIGURE 4 Nanotube
Reactor for CVD Synthesis of Carbon Nanobes in
Our Laboratory
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(II) CARBON NANOTUBES   Below is pictured a
diagram of the unique geometry of a carbon
nanotube as well as a transmission electron
micrograph of a single wall nanotube produced in
our department.  
FIGURE 2 Open Nanotube (Newman)   At 100-150
times the strength of steel yet only 1/60th of
its weight, nanotubes are being recognized as the
penultimate fiber with a promise for material
technology far surpassing all previous fibers yet
created. This promise, as noted, is far beyond
just the properties obtained with carbon fibers,
now used in the highest performance composites.
Potentially, future airplanes formed from


CARBON NANOTUBE
TEM OF NANOTUBE
  FIGURE 3 Nanostructure and TEM of single
wall nanotube as synthisized