Biomedical Engineering Reference
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effort has been directed toward the interactions that occur at the interfaces of the two
materials. These interfacial areas can be defined a number of ways. One such interface
is the surface of the wood itself. Another would be the wood or wood pulp fiber and
a third would be the interfaces that exist between water and the within the fiber walls.
The latter can even be broken down to the amorphous areas of the cellulose bundles and
the crystalline areas. The arrangement, size and degree of 'crystallinity' of the cellulose
bundles at the nanoscale can greatly influence the behavior of the materials in response
to water and water vapor at the macrolevel. Characterization of the interfaces, and the
relationships between water (liquid and vapor) and lignocellulosics at the nanoscale can
be achieved utilizing a combination of the newer available tools (e.g. atomic force
microscopy (AFM), scanning tunneling electron microscopy (STEM), etc.) and standard
technologies (e.g. inverse gas chromatography (IGC), transmission electron microscopy
(TEM), scanning electron microscopy (SEM), electron spectroscopy for chemical analy-
sis (ESCA), auger electron spectroscopy (AES), ultraviolet photoemission spectroscopy
(UPS) and time-of-flight secondary-ion mass spectroscopy (ToF-SIMS)). Older meth-
ods such as electro-kinetic analysis (EKA), water vapor sorption, differential scanning
calorimetry (DSC) and microcalorimetry are also very useful, especially when studying
the surface charge and thermodynamics in the interfacial regions.
The scope of the proposed research could include the influence of species, location
in the tree, site, process conditions, and the response of products in use to water and
water vapor. By developing a fundamental knowledge base at this level, tools may be
made available to allow companies in the forest products industry to 'design' trees for
the properties needed in a range of products, to produce them by utilizing processes
that are much more efficient in terms of the consumption of energy, water and raw
materials; and may even make available a renewable, sustainable resource to the devel-
opment of products currently made from less environmentally friendly materials. The
primary output from work on lignocellulosic/water interactions at the nanoscale will be
a knowledge base or 'toolbox' from a materials science perspective rather than a wood
products or papermaker's point of view. However, it will provide developers of prod-
ucts and processes in these disciplines the tools needed to improve current products and
processes as well as those needed for the development of entirely new products from
the forest.
Understanding and characterizing the interfaces in cellulose fibers at the nanoscale are
the first step toward modifying the fiber and enhancing its properties as a building block
for many products (existing and new). Using the water/lignocellulosic interaction (liquid
and vapor) as a probe will enable the understanding of the surface energies of the fiber and
permit us to more effectively add coatings (nanolayers), or other surface modifications; as
well as derivatize cellulose to meet new and existing product requirements (e.g. strength
enhancement, adhesion, and hydrophilic/hydrophobic properties). This knowledge base
will be applicable to virtually all products derived from woody and nonwoody plants
wherever water and lignocellulosics interact. With the exception of entirely new product
streams, the information developed will permit more effective utilization of the current
assets in the wood products and paper industries.
Outputs from this nanotechnology priority area would include the following: (1) a
package of fundamental knowledge relating to cellulose/water interfacial interactions
at
the
nanoscale;
(2)
a
model
based
on
the
fundamental
information
developed;
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