Patrik Schmuki talks with
ScienceWatch.com and answers a few questions about
this month's New Hot Paper in the field of Materials
Science. The author has also sent along images of their
Article Title: TiO2 nanotubes: Self-organized
electrochemical formation, properties and
Authors: Macak, JM;Tsuchiya, H;Ghicov, A;Yasuda, K;Hahn,
Journal: CURR OPIN SOLID STATE MAT SCI
Year: FEB-APR 2007
* Univ Erlangen Nurnberg, Dept Mat Sci, LKO, Martensstr 7,
D-91058 Erlangen, Germany.
* Univ Erlangen Nurnberg, Dept Mat Sci, LKO, D-91058
Why do you think your paper is highly
TiO2 nanotubes can be produced by a simple electrochemical
method which is based on a natural self-organizing process.
TiO2, as such, is a highly interesting functional material, and
the possibility to produce highly controlled nanostructured surface layers
of this material enhances and enables the tailoring of many of the
Moreover, not only the geometrical factors of the nanotube layers (e.g.,
length and diameter of the tubes) but also the crystal structure or
chemistry of the tubes can be modified by special treatments.
Therefore, as TiO2 nanotubes have such a broad range of
potential applications—solar cells, biomedical,
photocatalytic—the findings we reported were quickly picked up by the
Does it describe a new discovery, methodology, or
synthesis of knowledge?
It reviews some of the latest findings and provides new and unique concepts
on growth mechanisms.
Would you summarize the significance of your paper
in layman's terms?
Several experimental findings are pulled together and unified in easy to
understand concepts—experimentally, the key factors on how to grow
"nice" self-organized TiO2 nanotube layers are provided, but
also the phenomenon is explained to a level that seems plausible not only
to us, but to others as well.
The paper also highlights possible improvements of different important
technologies such as solar cells or biomedical implants by such
Moreover, an exciting part of the work is the fact that these highly
ordered nanotubular surface layers with a plethora of functional properties
can be prepared by a relatively simple and cheap electrochemical approach.
Merely apply some voltage to a titanium metal sheet immersed in the right
solution and, after some time, the entire surface will be covered with
vertically aligned titaniumdioxide nanotubes.
How did you become involved in this research, and
were there any problems along the way?
After a more or less coincidental finding, we followed up on the
electrochemical formation of self-organized TiO2 nanotubes for
several years and improved aspect ratio, tube-wall morphology, and
long-range ordering. Also, approaches to modify the nanotube properties
(e.g., doping, crystal structure, filling of the tubes, etc.) were explored
to pave the way for possible applications.
Two key findings were the essential role of the control of pH-gradient
within the tubes and the influence of non-aqueous electrolytes for the
process of nanotube growth. To conceptually realize this and experimentally
establish the optimum conditions took hard work and the dedicated efforts
of several Ph.D. students.
Where do you see your research leading in the
Further control over the nanotube shape, control over diameter, structure
etc., will allow the field of applications to increase. Currently,
biomedical applications (biocompatible coating, drug delivery) seem very
promising and we are dedicating a lot of effort toward this direction.
Do you foresee any social or political implications
for your research?
Indeed, in the long run, the basis of new biotolerant/or rejecting surfaces
may be provided.
And also, in the field of energy production or highly defined catalysis
applications several new concepts seem feasible.
Prof. Dr. Patrik Schmuki
University of Erlangen-Nuremberg
Department of Materials Science Institute for Surface Science and Corrosion
Erlangen, Germany Web |