Inside Look at Cellulose Provides Insight into Cotton
Crystals
By Rosalie Marion
Bliss
June 8, 2009 Using a neutron beam to study
nanocrystals, researchers have provided new information about hydrogen bonds
that connect the building blocks of cellulose, the main molecule in cotton
fibers and most other plant cell walls. The study was coauthored by
Agricultural Research Service (ARS)
scientists with lead collaborators from Los
Alamos National Laboratory in New Mexico and
Joseph
Fourier University in Grenoble, France.
The study, published in Biomacromolecules, brings researchers closer
to completely describing the structure of cellulose. That structure will
provide a greater understanding of the chemical and physical properties of
cotton. Researchers have been studying the molecular structure of cellulose for
more than a century.
To understand how cellulose changes when it is exposed to enzymes, water or
chemical treatments, researchers need to learn more about its hydrogen bonding
system. Certain enzymes, for example, are used to break down cellulose for use
as biofuel, while others are used to treat textiles, such as stonewashing of
blue jeans.
ARS chemist
Alfred
French and support scientist
Glenn
Johnson, both with the
ARS
Cotton Structure and Quality Research Unit in New Orleans, La., worked with
computer-based molecular models, and the cooperators worked with neutron
equipment. They looked at the bonds at both room temperature and at
temperatures so cold that atoms almost stop moving—about 430 degrees below
zero Fahrenheit.
The researchers sought to discover whether the hydrogen atoms continuously
transition or whether they remain in a fixed location. They detected only
static hydrogen atoms at both temperatures. That suggests there is generally a
well-ordered network of hydrogen bonds, and that there is also a different
network that occurs on surfaces of the nanocrystals and in regions of defects.
Knowing more about how cotton crystals interact with neighboring molecules
and their intramolecular electronic energy could eventually lead to a better
understanding of defects or weaknesses at the molecular level. That better
understanding could lead to improvements in permanent press and antimicrobial
finishes for consumer products.
ARS is the principal intramural scientific research agency of the
U.S. Department of Agriculture.
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