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Research Interests
Design, synthesis and investigation of
structure-property relationships of novel functional
polymers: polymers for advanced optic and electronic
applications; ‘smart’, stimuli-responsive polymers; nano-science
and technology; (semi)conducting conjugated polymers;
supramolecular chemistry.
Overview of Research
Our research interests and programs are
focused on the creation of novel functional polymer systems,
in particular for advanced electro / optical applications.
Our activities are mainly motivated by the persistent desire
for polymeric materials, which exhibit currently unavailable
properties. Polymers, as a group of materials, typically
offer an attractive combination between ease of
processability and final properties (mechanical, optical,
electrical, etc.). Especially the ability to design their
chemical structure virtually at will, but also the
possibility to control the often very rich phase behavior of
polymer systems allows one to minutely tailor the properties
of this remarkable class of materials. Thus, for the
development of new polymers and polymer-based compositions
and the exploration and exploitation of these systems, it is
of fundamental importance to identify and manipulate the
relevant molecular parameters that govern the macroscopic
property of interest. Consequently, the foundation of our
research is the molecular design, synthesis, and
structure-property relation of new polymeric systems with
tailored functionalities. The control of supramolecular
structure (often at the nanometer length scale), the use of
conventional and advanced processing schemes, and the
characterization and application of the final products are
often also relevant aspects of our research projects. Some
of these aspects, in concert with the very nature of
materials science, are highly interdisciplinary and, hence,
our research is conducted in a project-oriented fashion.
Current Activity
One of our current research topics is the
design, synthesis and exploration of well-defined conjugated
polymer networks. We have demonstrated that unsaturated
bonds comprised in conjugated polymers can readily
coordinate to transition metals and that under appropriate
conditions cross-linked conjugated networks can be formed.
We have also shown that these organometallic hybrid
materials exhibit very high charge-carrier mobility, and
demonstrated that such conjugated macromolecular networks
can overcome the notorious problems that are usually
associated with interchain charge-transfer through hopping
processes. Our current activities focus on the synthesis and
processing of various representatives of this exciting new
class of materials, the elucidation of their (opto)electronic
characteristics, and their application in semiconductor
devices. We have also expanded our activities to the
investigation of conjugated polymer networks that feature
covalent conjugated cross-links. These materials can be
conveniently synthesized and processed as aqueous
dispersions.
Another, relatively broad area of current
research is the development and application of functional
polymer blends. Minor fractions of a "functional additive"
are blended with an "inert matrix polymer" in order to
create - often after rather specific processing protocols -
a new material with a unique or unusual property matrix.
Examples include light-polarizing photoluminescent materials
based on uniaxially aligned photoluminescent dyes,
photoreactive polymers, and polymers with integrated
photoluminescent deformation sensors.
Other research
activities of the group are focused on the exploration of
new ion-conducting polymers for fuel cell and battery
applications, smart materials with dynamically controllable
stiffness, and organic-inorganic hybrid polymers for
high-temperature applications.
Recent Publications
“Conjugated Polymer Networks,” Weder, C., Chem. Comm.,
5378-5389. Invited Feature Article, Cover Picture.
(2005).
“Morphology of Polymer/Liquid Crystal Nanocomposite Tubes,”
Steinhart, M.; Zimmermann, S.; Schaper, A.K.; Ogawa,
T.; Tsuji, M.; Gösele, U.; Weder, C.; Wendorff, J.H.;
Adv. Funct. Mater., 15, 1656-1664 (2005).
“Thermally Induced Color Changes in Melt-Processed
Photoluminescent Polymer Blends,” Crenshaw, B.; Weder,
C.; Adv. Mater., 17, 1471-1476 (2005).
“Changing Colors with Excimers,” Crenshaw, B.; Kunzelman,
J.; Weder, C.; The Spectrum, 18, 20-26
(2005). Invited Review.
“2,2'-Bipyridine-Containing Poly(p-phenylene
ethynylenes) - Synthesis, Characterization, and Complexation
with Transition Metals,” Kokil, A.; Yao, P.; Weder,
C.; Macromolecules, 38, 3800-3807 (2005).
“Synthesis and Optical Properties of Metallo-Supramolecular
Polymers,” Iyer, P.K.; Beck, J.B.B.; Weder, C.;
Rowan, S.J.; Chem. Comm., 319-321 (2005). Among
10 most popular articles.
“Liquid Crystalline Nanowires in Porous Alumina: Geometric
Confinement versus Influence of Pore Walls,” Steinhart, M.;
Zimmermann, S.; Göring, P.; Schaper, A.K.; Gösele,
U.; Weder, C.; Wendorff, J.H.; Nano Lett., 5,
429-434 (2005). Cover Picture. Among most-accessed
articles January-June, 2005.
“Electronic Properties of Poly(p-phenylene
ethynylene)s; In: Poly(arylene ethynylene)s - From
Synthesis to Applications,” Voskerician, G.; Weder, C.;
Advances in Polymer Science Series Vol. 177; Weder, C., Ed.;
Springer, Heidelberg, 209-248 (2005).
Recent Publications
Presented 17 public lectures/seminars at national and
international meetings, workshops, companies, or other
universities.
Awards
2005 NSF-DMR Special Creativity Award
2002 DuPont Young Professor Award
2002 3M Non-Tenured Faculty Award
2001 DuPont Aid to Education Award
1994 Swiss National Science Foundation
Research Fellowship
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