Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter.
Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page 53
6
Workshop Wrap-up Session
ADDRESSING COMPLEXITY
Four workshop participants, Jennifer Sinclair Curtis of
the University of Florida, Michael Postek of the National
Mike Postek was struck by the obvious need to make
Institute of Standards and Technology (NIST), Pierre Ricou
multiple measurements on the types of complex materials
of Arkema, and Richard Conroy of the National Institute
that represent nanomaterials found in the real world. He
for Biomedical Imaging and Bioengineering (NIBIB) at the
noted the development of a wide range of new tools for
National Institutes of Health (NIH), were asked to provide
nanomaterial characterization and the continuing advances
closing comments. Chosen for their diverse perspectives,
being made with instrumentation, such as the applications of
each panelist discussed what he or she heard during the
the soft x-ray tomography, the cryogenic light microscopy,
workshop and what some next steps might be. The panel
aberration-corrected transmission electron microscopy (TEM)
comments were followed by an open discussion period when
and scanning electron microscopy (SEM), and in situ TEM. He
all workshop participants were given the opportunity to
also raised the need for a database of available technologies.
respond to the panelists and raise additional issues.
Postek expressed a worry that cuts to research and devel-
opment budgets, particularly in industry, are hampering
PATH FORWARD technology development at a time when need in the nano-
characterization field is growing. However, he also noted
Jennifer Curtis heard three main topics discussed dur-
that a great deal of advanced characterization technology is
ing the workshop: implications, understanding complex
available at the national laboratories and at NIST, along with
processes, and new characterization techniques for small
investigators who are more than willing to collaborate and
particles. She said that health and environmental implica-
cooperate in this area.
tions seem to motivate much of the work in characterizing
M odeling also touches on complexity, Postek said.
and modeling small particles. Given that motivation, there
Industry needs tools to model complex composites for use
is a need for greater understanding of fine particles and the
in high-performance applications. The potential cost sav-
dynamics of their behavior. There is another need to define
ings from having models capable of predicting material
the methods that are capable of distinguishing between single
performance would be huge, as it would be if models were
nanoparticles and agglomerates.
available to predict the effect that process variables have on
A key takeaway message for Curtis was that the modeling
the properties of materials with complex surfaces and surface
community faces some validation challenges related to the
chemistries.
lack of detailed experimental data. She believed it would be
useful to the field to compile a database of the available char-
COMMON GROUND
acterization techniques and their key features in terms of the
type of material they can handle and the characteristics and
Pierre Ricou’s impression was that small-scale character-
properties that they measure. Such a database may increase
ization is a focal point for many different parts of the nanotech-
the use of these powerful techniques in areas beyond those
nology world. From industry’s perspective, there is a need to
for which they were developed.
characterize and understand the properties of materials to cre-
53
OCR for page 54
54 CHALLENGES IN CHARACTERIZING SMALL PARTICLES
ate complex materials that can meet a wide range of demands. tion to the biomedical application phase. NIBIB also offers
From an environmental scientist’s perspective, there is a need fellowships that are designed to create time for mid-career
to characterize materials to understand what happens to those researchers in the physical or quantitative sciences to develop
materials when they enter the world outside of the laboratory projects in the life sciences.
or factory. Although each group is tackling different issues, Conroy said that all of the other NIH institutes have simi-
they are united by a need to characterize the properties and lar initiatives, and NIBIB also supports Small Business Inno-
behaviors of complex materials in complex environments. vation Research (SBIR) grants in the area of bioengineering
Ricou was also impressed by the wide range of tech- in nanotechnology.
nologies that are now available for characterizing nanoscale
materials. He reiterated the importance of creating a data-
OPEN DISCUSSION
base of technologies, and he stated that instrument vendors
should hear more about the challenges facing those who
Characterizing Aggregates—Trading Detail for Utility
need to better characterize nanomaterials. He would like to
see development of the ability to perform spectroscopy on Jim Litster said he was amazed by what he heard during
dynamic systems at the nanoscale to better understand how the workshop about the ability to measure individual small
the chemistry of a nanomaterial changes over time, which particles. He added, however, that because the functionality
would benefit many aspects of nanocharacterization. of the nanoparticles in use depends very much on the struc-
tures in which they are embedded, there is still a need for
techniques that are just as powerful at characterizing the state
FUNDING OPPORTUNITIES
of dispersion or aggregation. Developing the techniques and
Richard Conroy said that he came away from the presenta- instrumentation to attack that problem is the logical next step
tions with two questions: for the field.
Doug Ray agreed that there is not as much capability in
• Should we study function first or structure first? the area of concentrated liquids and solids. He asked, “Is it
• Should we measure something just because we can? because it is just really hard and the community is not there
yet, or is it because we have elected somehow to not focus
This second question is particularly important from the in that arena?” He does not know the answer but thinks it is
NIH perspective, because many measurements correlate an interesting question to consider.
weakly with outcomes, and thus it is not always clear that Mark Barteau added that work in this area might focus on
the measurements are useful when considering the research “diagnostic,” meaning that it may not be necessary to know
that has gone into them. He added that consideration of the all the details of how nanoparticles behave in a matrix. It
question of safety and efficacy is also important, in terms of might be enough now to characterize these complex materials
the comparative effectiveness and safety of nanotechnology- according to a certain number of reduced parameters or
based products versus bulk materials. “lumped” parameters. He is aware of some movement in
Conroy provided a quick overview of some of the fund- that direction, but the emphasis on incredible levels of detail
ing opportunities at NIH. Part of NIH’s current mission is and expensive instruments does not match the degree found
to bridge the life and physical sciences, and, in that regard, in nanoscale imaging. He wondered, however, if looking at
he thought the nanomaterial characterization community more complex systems at lower levels of detail that are still
would be interested in a number of initiatives. Most of the diagnostic might be where the field makes the biggest impact.
initiatives are funded by NIBIB or the National Institute of Ray added that the atmospheric sciences are starting to move
General Medical Sciences (NIGMS), with NIBIB focusing from a more detailed view to one that reduces the amount of
more on the clinical side and NIGMS focusing more on basic information and creates useable models.
research. One new initiative is aimed at applying technolo- Conroy noted that NIH is interested in where the field
gies from the physical sciences to life sciences problems. A is going on this matter. He believes that the relevant ques-
significant feature of this initiative, the grant review panel tion relates to how much detail on specific characteristics is
includes experts from both NIH and the National Science needed to predict biological outcomes. Ricou agreed with
Foundation (NSF), with the latter providing a physical this idea but stressed the importance of understanding these
science perspective to the NIH review process. A partner systems in fine detail to know what is important when trying
initiative aims to translate ideas from the physical sciences to predict relevant behavior.
into the clinical arena.
Another NIBIB initiative is the bioengineering research
Chemistry and Stability
partnership program that encourages investigators to form
a partnership between the life and physical sciences to Levi Thompson pointed out that many of the particles
translate a concept, technique, or tool from the demonstra- that were discussed at the workshop are semiconductors and
OCR for page 55
55
WORKSHOP WRAP-UP SESSION
wondered if the properties of those particles are influenced build the measurement tools that the industry has needed
by exposure to light. He asked if anybody had performed as it meets its technology goals. Nothing like that exists
the requisite studies to determine whether photocatalytic for nanotechnology. He acknowledged that creating such a
or photolytic processes are important to particle reactivity. consortium to define what is happening in nanotechnology
Satya Kuchibhatia from the Pacific Northwest National would be difficult given the disparate nature of this commu-
Laboratory answered that his group has looked at cerium nity. “Perhaps several of these kinds of consortia are needed
oxide nanoparticles and found that exposure to light defi- to help shape this field and get people together to talk about
nitely influences the transformations happening on the nano- what their needs happen to be,” he suggested.
particles. He also explained that how a nanoparticle responds Rhonda Stroud believes that having a focus is great, but
to light changes over time and that his group has noticed it does not necessarily have to be on commercial applica-
changes between the times when a particle is received from tions alone. As a civil servant, her customer is the American
a vendor and when it is studied. Where the particles are public, and she asks herself, “Can I justify working on space
manufactured also makes a difference, which is likely due particles to the taxpayer?” She believes that the common
to the humidity of the manufacturing location. issue is really quality of life. Everyone is producing infor-
Finlayson-Pitts said that the field of atmospheric chemis- mation and products that improve the quality of life. This is
try is starting to pay attention to the photochemical properties what air quality, new drug treatments, and astronomy have
of nanoparticles. The photochemistry of small particles can in common. They may not all have immediate commercial
be quite different from the photochemistry of larger particles, applications, but they can be important to the American
primarily because of differences in surface-to-volume ratios. people nonetheless. Therefore, a roadmap should look at
As an example, she described differences in the photolysis what the impact of knowledge as well as products will be
of nitrate ion that occurs when it is surrounded by a solvent on the average person.
shell on a bulk surface compared to when it is at an interface. A participant agreed that the ultimate goal is to serve the
“The whole issue of photochemistry at interfaces is certainly people, but, at the end of the day, the commercial aspect is
one that is getting increasing attention in the atmospheric important because it is the means to get to that goal. For
community,” she said. Thomson added that researchers who example, catalysis is very important for many applications.
study catalysis, photocatalysis, and electrocatalysis have Researchers will make useful and environmentally benign
been considering these issues for many years, and it might c atalysts from ruthenium or rhodium. However, those
be an intersection that can be probed more. materials are expensive, so in poorer countries that same
reaction will be carried out without the catalyst and will use
excess reagent that gets dumped into waterways because
What’s the Focus?
pollution control standards are lax. Ultimately, if knowledge
One participant commented that while the presentations does not make money or save money, no matter how useful
were very informative, there was a lack of focus in terms of it is, people will not use it.
an industrial driver, that is, how at the end of the day will Ray replied that while certain sectors, such as energy or
this research help to develop new products. pharmaceuticals, are driven by commercial interests, other
Kuchibhatia and his colleagues at the Pacific Northwest sectors such as the defense industry are not. He believes that
National Laboratory are encouraged that the field is mov- there are sectors where commercial drivers are in place and
ing beyond the excitement of getting a good TEM image are appropriate, and there are other sectors where they are
to search for details about surface chemistry with an eye not. The nation supports research in areas such as astronomy,
on developing nanoparticles with specific properties. The not for an immediate commercial benefit but for quality-of-
goal, he said, has gone from seeing structure to combining life issues and the long-term benefits that the research might
structure with a desired chemical property. “At the end of the produce. Stroud pointed out that the Department of Defense
day, it is the chemistry that is going to make the magic, not does a significant amount of work on the development or the
just the structure,” he said. advancement of catalysts and energetic materials where
Postek added that a roadmap created by the semi- the driving force is not the immediate bottom line, but the
conductor industry years ago has guided the industry since need to protect the American people.
the 1980s and has allowed instrument manufacturers to
OCR for page 56
