2007 Volume 1 #1
Along with Rana Sodhi and Peter Brodersen,
it is my pleasure to offer our first newsletter from Surface Interface
Ontario. The laboratory, established in 2002 with a Canadian Foundation
of Innovation award, is now in the midst of a significant expansion
of its capabilities and activities. This happy circumstance is the
result of a second CFI award from the Leading Edge Fund, announced
late last year. More details of this exciting initiative can be found
below. Sample preparation and handling are critical aspects of the
study of surfaces and hence, an important part of the expansion will
be a user laboratory dedicated to sample preparation and handling.
The high quality and wide-ranging impact of the research activities
of you, our users, combined with expanding needs for high quality,
collaborative surface analysis is the reason that CFI chose to invest
further in SI-Ontario. Therefore, our success is really your success.
Chuck Mims (left) shares some
thoughts with Jim Robinson of Datacomp
during the visit to Thermo Electron in February.
We plan to bring you a newsletter several times a
year in order to inform you of our operations and capabilities as
well as to highlight recent advances. We hope that this will stimulate
new ideas for our current users and trigger new research programs
in the research community at large. We look forward to working on
your problems in surface chemistry and of course, welcome your comments
to download a full pdf version of the first newsletter
from Surface Interface Ontario or
click on any of the links below to read any of the individual articles
in the newsletter as listed
SI-Ontario Receives Canadian Foundation
for Innovation Award
SI-Ontario will benefit from a $1.36 million investment by the
Canadian Foundation for Innovation (CFI), as announced last November.
The proposal, which was submitted to the Leading Edge Fund, was
entitled An Integrated Centre for Surface and Interfacial
Analysis of Advanced Materials and spear-headed by Prof. Charles
Mims. The total budget, with in-kind and matching contribution,
will come to $3.4 million. The award will not only allow SI-Ontario
to upgrade its equipment but will greatly expand the scope of work
it can currently undertake. The new infrastructure will allow Canadian
researchers continued access to state-of-the-art surface analysis
equipment and the related expertise, as well as comprehensive surface
preparation facilities, thereby ensuring their position at the leading
edge for years to come. See article on "Enhancing the capabilities
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Enhancing the Capabilities of SI-Ontario
The research supported by SI-Ontario is as diverse as its client
base and is of high impact. A common thread is the need for the
best available surface and interface chemical information. While
the current facilities have provided a critical component to the
supported research, advances in technology have necessitated further
investment in the infrastructure to allow leading edge quality and
fulfill needs currently unmet both regionally and nationally. The
new CFI funding allows us to now meet these goals.
Four main categories have been highlighted for enhancement.
- ToF-SIMS upgrade: This is to include the new Bi cluster ion
source, which will replace the present Ga source; a third ion
gun column to house a new C60 ion
source; pulsed secondary electron detection and associated data
systems; and improvement to the sample-cooling system to -150°C.
- Imaging XPS/AES system: A small spot (~ 10 µm), monochromatic
(angle-resolved) XPS with imaging capabilities, a sample treatment
chamber, heating-cooling (-150°C - 600°C), and Auger imaging
with 100 nm spatial resolution.
- Specialised sample treatment/preparation facilities: This will
include a cryomicrotoming/freeze fracture, custom stand-alone
preparation chamber; a vacuum suitcase and other (cryo and inert
gas) transfer devices; a surface profilometer; polishing equipment;
and a glovebox.
- Expanded laboratory/user facility: To house the expanded facility,
lab space will have to be doubled. The new space will house the
old XPS - for use on dedicated projects, preparation chamber/equipment,
glovebox and space for visitors. In addition to more data stations
in-house, the proposal also includes networking capabilities with
Further details will be posted on our website - www.si-ontario.utoronto.ca.
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to Thermo Electron and Kratos
In order to help decide which XPS fits SI-Ontario's user base the
best, Rana Sodhi, Peter Brodersen and Chuck Mims visited both Thermo
Electron (E. Grinstead, UK) and Kratos (Manchester, UK) in early
February. Thermo offers 2 instruments of interest: the Thetaprobe
and the Escalab 250, while Kratos flagship - the Ultra, is
also a leading contender.
The advantage of the Thetaprobe is its ability to do parallel angleresolved
XPS, negating the need to tilt the sample. By focusing its X-ray
down to 15 µm, it is able to do small spot analysis, achieving
good count-rate, while stage-rastering allows imaging capabilities.
Visiting the team at
Thetaprobe is in the foreground, Escalab 250 is in the background.
Both the Ultra and the Escalab use a parallel imaging
mode. By decreasing the aperture in the lens system, small areas
of analysis can be defined. Scanning the plates allows both systems
to generate a map. Both systems claim a spatial resolution of better
than 3 µm. Angle-resolve XPS is done by tilting the sample.
The team at Kratos busy demonstrating
the performance of the Ultra.
A final instrument, Ulvac-Phis Versaprobe, has just come
onto the market. Unlike the instruments above, it images by scanning
a small spot X-ray.
All in all, it is going to be a tough decision! A comprehensive
set of real samples was taken over to compare performance. Also,
the ability to integrate sample preparation chambers is of importance.
The good thing is that whatever our decision, we cant really
make a mistake.
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Hannibals Possible Routes Invasion
of Italy - 218 BC
Perhaps one of the more esoteric applications of SIMS presented
at SIMS XV in Manchester in 2005 was entitled ToFSIMS applied
to historical archaeology in the Alps .
According to literature, there are 3 possible invasion routes followed
by Hannibal during the second Punic War (see
map). While proof exists that he used the Col de le Traversette,
ancient literature suggests that there should be burnt rock on the
Italian side of the Alps due to his firing of the rocks.
The Col du Clapier is the only pass where fired rock
has been found.
The question is, is this due to timber being used
as related to Hannibal, or is it more recent, say to a modern day
SIMS images for a cross-section of the
burnt rock are shown here.
Of interest is the presence of K on the burnt crust
and within the fissures. The presence of K has been attributed directly
to the firing, resulting from the ash residue that would remain
after firing with timber. This would not be expected if gasoline
had been used for the firing.
Thus the SIMS results are in broad agreement with the historical
literature which states that Hannibal did use timber to fire the
rocks and clear his route. This alone is not positive proof that
he indeed did this and used the Col du Clapier, however, it does
confirm that timber was used in this case.
 R.N.S. Sodhi, W.C. Mahaney and M.W. Milner, Applied Surface
Science 252 (2006), p7140.
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SOFCs - Isotope Exchange and Depth Profiling
Results from SI-Ontarios collaborative work with University
of Houston (Chemistry & Physics) on solid oxide fuel cells (SOFCs)
were reported at SIMS XV in Manchester (UK) in the fall of 2005.
The presentation highlighted the ability of SI-Ontarios ToFSIMS
instrument to study the oxygen transport kinetics of newly developed
mixed ionic electronic conductor cathode materials. SOFCs are highly
efficient, non-polluting electrochemical energy converters, directly
transforming chemical energy into electrical energy.
For commercialization, operation of SOFCs at intermediate temperatures
(500700°C) is desirable in order to reduce costs and enhance
cell stability. At lower temperatures, cathode resistance becomes
the limiting factor in overall cell performance. Current efforts
focus on finding oxides that are electrolyte compatible and which
have the high oxygen diffusion and surface exchange kinetics necessary
for low electrode resistance.
Figure 1. Dual beam depth profile
and other cathode ions
Isotope exchange and depth profiling (IEDP) has been used to evaluate
oxygen transport kinetics. Samples (both thin films and bulk) are
equilibrated in oxygen (0.2 atm) with normal isotopic abundance
and then exposed to 18O (99% isotopic
abundance) and rapidly quenched. The resulting 18O
profiles are determined via ToF-SIMS using either dual beam sputter
analysis (thin film cathode - Fig. 1) or imaging of cross sections
(bulk cathode - Fig. 2). The extracted profiles are used to determine
oxygen surface exchange and oxygen bulk diffusion coefficients.
Figure 2. Depth profile (bottom) extracted from image (center)
of area of interest (top)
In this project, the imaging capability of our TOF-SIMS IV instrument
has also proven useful for investigating profile phenomena, including
lateral heterogeneities as a function of depth in thin films and
gross distortions in 18O profiles
of cross-sections caused by e.g. cracks in the material (Fig. 3).
Figure 3. 18O
map (l) and secondary electron image (r) of coincident area
For further information on this project, see Journal of Materials
Chemistry, DOI:10.1039/B618345J (2007).
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Heating & Cooling
Being able to heat or cool a sample in situ can be very important.
For example, certain polymers can restructure, showing different
orientations between the wet and dry states. The ToF-SIMS has a
special heating-cooling stage (below), which allows the temperature
to varied between -130°C - 600°C in both the preparation
and analytical chambers.
In a recent study, Sosnik  has looked at collagen/poloxamine
hydrogels by a deep freezing ToF-SIMS approach in order
to study the availability of the collagen molecules at the surface
of the hydrated polymer structure and consequently their ability
to induce the attachment of cells on the designed matrices. Three
matrices considered: collagen, poloxamine and poloxamine + collagen.
The samples were cast in a special Cu holder which was attached
to the cooling stage and placed in the transfer chamber. This was
flushed with dry N2 and cooled down
to -120°C at which point the vacuum was started. After placing
in the analytical position, the sample was heated in 5°C increments
until the H2O sublimed off.
The figure above shows the positive spectrum at -95°C
and it can be seen from the marked (*) series of peaks due to H(H2O)n+
fragments that the water has not totally sublimed off. Heating the
sample drives this remaining H2O.
The figure below shows the positive ion spectrum of a collagen/poloxaminemethacrylate
hydrogel heated to 65°C, which shows peaks characteristic
of both the collagen and the pure hydrogel.
The work confirms the presence of collagen at the surface which
is evenly distibuted as seen in positive ion image shown below.
 A. Sosnik, R.N.S. Sodhi, P.M. Brodersen and M.V. Sefton, Biomaterials
27 (2006), p2340.
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