LowPressure Plasma Process for Nanoparticle Coating

1
Low-Pressure Plasma Process for Nanoparticle
Coating Investigators Farzad Mashayek, MIE/UIC
Themis Matsoukas, ChE/Penn State Prime Grant
Support NSF
Problem Statement and Motivation
Simulated flow of ions over a nanoparticle
Nanoparticles of various materials are building
blocks and important constituents of ceramics and
metal composites, pharmaceutical and food
products, energy related products such as solid
fuels and batteries, and electronics related
products. The ability to manipulate the surface
properties of nanoparticles through deposition of
one or more materials can greatly enhance their
applicability.
Nanolayer coating on a silica particle
Key Achievements and Future Goals
Technical Approach

• The batch reactor is already operational and has
  been used to demonstrate the possibility of
  coating nanoparticles.
• A reaction model has been developed to predict
  the deposition rate on the nanoparticle surface.
• The possibility of using an external magnetic
  field to control the trapping of the particles
  has been investigated computationally.
• The experimental effort is now focused on the
  design of the continuous mode reactor.
• The computational effort is focused on
  development of a comprehensive code for
  simulation of the plasma reactor, nanoparticle
  dynamics, and surface deposition.

A low-pressure, non-equilibrium plasma process is
developed using experimental and computational
approaches. Two types of reactors are being
considered. The first reactor operates in batch
mode by trapping the nanoparticles in the plasma
sheath. Agglomeration of the particles is
prevented due to the negative charges on the
particles. The second reactor is being designed
to operate in a continuous mode where the rate
of production may be significantly increased.
This reactor will also provide a more uniform
coating by keeping the nanoparticles outside the
plasma sheath.
2
Nanostructured Sensors for Detecting Low Levels
of Hydrogen at Low Temperatures Investigators
J. Ernesto Indacochea Ming L. Wang, Materials
Engineering Department Prime Grant Support
National Science Foundation
Problem Statement and Motivation

• Recent research thrusts for alternate methods of
  power generation has turn to production and
  storage of H2 as alternative fuel, as it is the
  most environmental friendly fuel.
• It is foreseen that H2 will become a basic energy
  infrastructure to power future generations
  however it is also recognized that if it is not
  handled properly (e.g. transportation, storage),
  it is as dangerous as any other fuel available.
• Ultra sensitive hydrogen sensors are urgently
  needed for fast detection of hydrogen leakage at
  any level, such as the H2 leaks in solid oxide
  fuel cells (SOFC).

Technical Approach
Key Achievements and Future Goals

• This investigation is being performed in
  collaboration with the Materials Science Division
  of Argonne National Laboratory.
• Nanotubes have been selected because their high
  surface-to-volume ratio will lower requirements
  for critical volumes of H2 to be detected without
  compromising the sensitivity of the sensor.
• Pd-nanotube assemblies will be processed by ANL
  and initial hydrogen sensing tests will be
  conducted at their facilities.
• The nanostructured MOS sensor will be assembled
  at UIC-Microfabrication Laboratory this will be
  tested first in H2 atmospheres, where the H2
  levels and temperature will be adjusted.
• The final stage of the study will involve field
  testing in SOFCs and detect hydrogen evolution
  in acidic corrosion of metals.

• Pd nanotube assemblies have been fabricated
  successfully at the Argonne National Laboratory.
  Pd nanotubes excel in high sensitivity, low
  detection limit, and fast response times in
  hydrogen sensing.
• These nanotubes show an expanded surface area
  and granular nature, in addition to the high
  capability for dissociation of molecular
  hydrogen.
• Electrochemical techniques will be used to
  monitor H2 evolution with time.
• These nanotubes will be incorporated into the
  design and fabrication of a nanostructured MOS
  sensor which will be evaluated for H2 detection.

3
Molecular Simulation of Gas Separations Sohail
Murad, Chemical Engineering Department Prime
Grant Support US National Science Foundation
Problem Statement and Motivation

• Understand The Molecular Basis For Membrane
  Based Gas Separations
• Explain At The Fundamental Molecular Level Why
  Membranes Allow Certain Gases To Permeate Faster
  than Others
• Use This Information To Develop Strategies For
  Better Design Of Membrane Based Gas Separation
  Processes For New Applications.

Technical Approach
Key Achievements and Future Goals

• Determine The Key Parameters/Properties Of The
  Membrane That Influence The Separation Efficiency
• Use Molecular Simulations To Model The Transport
  Of Gases i.e. Diffusion or Adsorption
• Focus All Design Efforts On These Key
  Specifications To Improve The Design Of
  Membranes.
• Use Molecular Simulations As A Quick Screening
  Tool For Determining The Suitability Of A
  Membrane For A Proposed New Separation Problem

• Explained The Molecular Basis Of Separation of
  N2/O2 and N2/CO2 Mixtures Using a Range of
  Zeolite Membranes.
• Used This Improved Understanding To Predict
  Which Membranes Would Be Effective In Separating
  a Given Mixture
• Used Molecular Simulation to Explain the
  Separation Mechanism in Zeolite Membranes.