Nanoscience Turns Green

NEW VOICES IN CHEMISTRY
JAMES E. HUTCHISON
nanoscale assemblies fabricated using green
assembly methods are particularly attrac-
NANOSCIENCE
tive solutions to this long-term problem.
We are currently investigating the elec-
trical properties of nanoscale assemblies
TURNS GREEN
that transport charge through sequential
tunneling events and may form the basis
Molecular-level materials assembly with chemical for future electronic devices. The assem-
building blocks offers promise, opportunity
blies are prepared by biomolecular nano-
lithography, a biomimetic method of
We face serious economic cal building blocks whose properties can be organizing metal nanoparticles into
and environmental chal-
tailored at the molecular level, principles
assemblies designed to incorporate the
lenges during the next few
of green chemistry can be readily incor-
aims of green chemistry. A biopolymer
decades as a consequence
porated into materials design and produc-
template stretched out on a surface acts as
of emerging new econo-
tion. Throughout the design and develop-
a scaffold for chemical assembly of the
mies and continuing population growth.
ment process, chemists will have an
nanoparticles into well-defined architec-
Projected demands on natural resources
opportunity and a responsibility to practice
tures, such as lines and grids. This
significantly exceed Earth’s resource base
green chemical strategies.
approach has already led to nanoscale
and thus threaten our environment and
The use of chemical building blocks to
assemblies that demonstrate stable elec-
our way of life. Given the central role of
assemble materials offers many advantages.
trical behavior at room temperature. The
chemical products in modern societies, the
Building blocks can be synthesized using
assemblies appear to be tolerant of defects
development of sustainable chemical prac-
green preparation methods and assembled
and useful in building nanoscale circuits.
tices is essential to avoid depleting our nat-
under mild, reversible reaction conditions
This is just one example of how molec-
ural resources and damaging our ecosys-
that provide low-energy routes to correct
ular-level control can produce functional
tems. Chemists must invent and develop
errors in the assembly. In principle, assem-
nanoscale assemblies through green syn-
sustainable chemical practices if our envi-
blies can even be disassembled and the
thesis methods. A generalized road map
ronment and economies are to thrive in
building blocks reused. With respect to
for the future design and development of
this century.
performance, molecular assemblies allow
green nanoscale materials involves the use
Environmentally benign or “green”
of green chemistry to prepare the
chemistry strives to address environ-
building blocks, chemical assembly of
CK LIU
mental protection and sustainability A
building blocks for circuit fabrication,
through hazard reduction and BY JO
templates to pattern features on sur-
T
improved efficiency. Industrial and
faces, and molecular-level tuning to
PHO
academic chemists have used green
design defect-tolerant systems and sys-
chemistry to develop new processes
tems that take advantage of the third
and products that reduce hazards to
dimension. The challenge for the
the environment and human health.
future is to use these principles to
However, to date, the scope of green
design high-performance and green
chemistry remains limited primarily to
materials by taking advantage of our
the transformations of molecular
abilities to control properties at the
species by using new catalysts or alter-
molecular level.
native reaction media. The develop-
BUILDING SKILLS Hutchison (standing) and
To meet the challenges I describe,
ment of green chemical methods to pre-
graduate student Kathryn Parent observe while
we will need to change our educational
pare functional high-performance
graduate student Marvin Warner acquires data.
programs to prepare students to excel
materials, particularly nanoscale mater-
in green chemistry and nanoscience,
ials, has been virtually unexplored and offers
properties to be easily tuned and provide
both of which are highly interdisciplinary
a significant opportunity for the future.
opportunities for facile construction of
areas. Future curricula must continue to
Controlling properties at the molecu-
three-dimensional materials.
provide students with fundamental train-
lar level is a key to success in both nano-
Combining green chemistry with
ing in chemical principles and prepare
science and green chemistry. As the impor-
nanoscience will have a significant impact
them to work with a wide range of scien-
tant length scales in functional materials
on electronic materials. Because many haz-
tists, engineers, and policy makers.
approach nanometer dimensions, chemists
ardous materials are used in traditional
are already playing key roles in developing
semiconductor manufacturing processes,
James E. Hutchison is an associate professor of
and manufacturing new materials and
alternative technologies designed in accor-
chemistry and a member of the Materials Science
devices. In the future, chemists will
dance with green chemical principles are
Institute at the University of Oregon, Eugene. He
develop alternative device structures,
needed. At the same time, as the sizes of
received a B.S. in chemistry from the University of
invent methods for organizing matter on
electronic devices approach the nanoscale,
Oregon in 1986 and a Ph.D. in organic chemistry
short length scales, and provide solutions
continued miniaturization faces funda-
from Stanford University in 1992. He completed
for interfacial reactivity issues that arise as
mental physical limitations and exponen-
a postdoctoral fellowship at the University of North
surface-to-volume ratios increase. Because
tially rising manufacturing costs. Alterna-
Carolina, Chapel Hill. Previously, Hutchison was
many of these approaches involve chemi-
tives to silicon-based devices based on
on the faculty at Stanford University.