A cross-campus collaboration led by materials science professor Uli Wiesner results in visual confirmation of 12-sided, nanoscale cage structures, which could have medical diagnostic and therapeutic... Read more about Collaboration yields discovery of 12-sided silica cages
Uli Wiesner studied Chemistry at the Universities of Mainz and California, Irvine. He received his Chemistry Diploma in 1988 from the University of Mainz, Germany, and gained his Ph.D. in 1991 with work on optical information storage in liquid crystalline polymers in the group of Prof. H. W. Spiess at the Max-Planck-Institute for Polymer Research, Mainz. After his Ph.D. he was a postdoctoral fellow at the Ecole Superieure de Physique et de Chimie Industrielle de la ville de Paris (E.S.P.C.I.), France, with Prof. L. Monnerie studying the morphology and dynamics of aromatic terpolyesters. In 1993 he returned to the group of Prof. H. W. Spiess were he finished his Habilitation in 1998 with work on structure, order, and dynamics in self-assembled block copolymer systems with additional interactions. He joined the Cornell MS&E faculty in 1999 as an Associate Professor and became a Full Professor in 2005. Since his arrival at Cornell he works at the interface between polymer science and solid-state chemistry. The goal of his research is to combine knowledge about the self-assembly of soft materials with the functionality of solid-state materials to generate novel hierarchical and multifunctional hybrid materials. Uli Wiesner is the author of about 100 articles in peer-review journals and books and is currently an editorial and advisory board member of multiple scientific journals. Based on work at Cornell in 2003 he co-founded Hybrid Silica Technologies, Inc., Ithaca, NY, with the goal to provide "green" multifunctional hybrid nanomaterials for life science applications and beyond. He is the recipient of multiple awards, including a Ph.D. Award of the Hoechst AG, the Carl Duisberg Memorial Award of the German Chemical Society, an IBM Faculty Partnership Award and Mr. & Mrs. Richard F. Tucker'50 Excellence in Teaching Award of Cornell University. Since 2007 he is a member of the Nanotechnology Technical Advisory Group (nTAG) of the President's Council of Advisors on Science and Technology (PCAST). In November 2008, he was elected Spencer T. Olin Professor of Engineering.
The goal of current research in the Wiesner group is to combine knowledge about the self-assembly of soft polymeric materials with the functionality of solid-state materials to generate novel hierarchical and multifunctional hybrid materials. Research results of the group on the use of blocked copolymers as structure directing agents for inorganic materials suggest that in analogy to biology, the sequence information of higher order blocked synthetic macromolecular architectures may be used to encode information about hierarchical structure of co-assemblies with ceramic or other materials. These principles may permit the design of entirely new classes of functional materials that have no analogue in the natural world with potential applications ranging from power generation and energy conversion all the way to the life sciences.
As a particular model system to understand structure formation principles, silica-based hybrids from block copolymer mesophases have been studied extensively over the last ten years. One of the main working principles involves utilizing the thermodynamics of amphiphilic block copolymers, i.e., knowledge about their self-assembly behavior (bottom-up) to structure direct precursors for silica-type oxides. In the meantime these principles have been extended to other oxides as well as to non-oxide ceramics (e.g., SiCN). Synthesis results in mesostructured hybrid materials with structure control down to the nanometer length scale that upon, e.g., thermal processing can subsequently be converted into purely ceramic materials with preserved structure (e.g., mesoporous materials). The final materials have a broad range of potential applications in, e.g., catalysis and separation.
A second major current research direction of the Wiesner group focuses on a novel class of fluorescent core-shell silica nanoparticles, now referred to as C-dots, with potential applications, e.g., as fluorescent labels in biolabeling and bioimaging. Water-soluble C- dots encapsulate multiple organic fluorophores into a solid-state silica environment, thereby improving their photophysical properties as compared to the free dye in water. C-dots have narrow size distributions and in the 20-30 nm size range achieve brightness levels reaching those of semiconductor quantum (Q-) dots with simultaneously enhanced photostability over free dye in aqueous solutions. They are synthesized through a modified Stöber process and overcome toxicity and disposal issues of competing Q-dot technologies. As a result of their optical property profiles they constitute an attractive alternative to existing materials platforms for applications in information technologies and the life sciences requiring bright fluorescent probes. Fundamental studies are aimed at understanding and controlling optical phenomena of this novel class of radiative nanoparticles and of optical structures and devices that integrate them.
Some of the research projects that are currently pursued in the group include:
1. formation mechanisms of nanostructured polymer-inorganic hybrid materials from diblock- and triblock-copolymers and nanoparticles 2. mesoporous oxides and non-oxides for power generation and energy conversion 3. novel dendron derived structure directing agents for functional materials 4. nanostructured block copolymer-silica hybrid thin films 5. synthesis and characterization of C dots from various organic fluorophores 6. preparation of multifunctional C dots 7. C dots as labels and probes in bioimaging 8. locomotive motion in hydrogels from symmetry breaking of gel volume phase transitions
- Tan, K. W., B. Jung, J. G. Werner, E. R. Rhoades, Michael Thompson, Ulrich B. Wiesner. 2015. "Transient Laser Heating Induced Hierarchical Porous Structures from Block Copolymer Directed Self-Assembly." Science 349 (6243): 54-58.
- Phillips, E., O. Penate-Medina, P. B. Zanzonico, R. D. Carvajal, P. Mohan, Y. Ye, J. Humm, M. Gönen, H. Kaliagian, H. Schöder, H. W. Strauss, S. M. Larson, Ulrich B. Wiesner, M. S. Bradbury. 2014. "Clinical translation of an ultrasmall inorganic optical-PET imaging nanoparticle probe." Science translational medicine 6 (260): 260ra149.
- Sai, H., K. W. Tan, K. Hur, E. Asenath-Smith, R. Hovden, Y. Jiang, M. Riccio, David Anthony Muller, V. Elser, Lara A. Estroff, S. M. Gruner, Ulrich B. Wiesner. 2013. "Hierarchical porous polymer scaffolds from block copolymers." Science 341 (6145): 530-534.
- Suteewong, T., H. Sai, R. Hovden, D. Muller, M. Bradbury, S. M. Gruner, Ulrich B. Wiesner. 2013. "Multicompartment mesoporous silica nanoparticles with branched shapes: An epitaxial growth mechanism." Science 340 (6130): 337-341.
- Warren, C., M. R. Perkins, A. M. Adams, M. Kamperman, A. A. Burns, H. Arora, E. Herz, T. Suteewong, H. Sai, Jeffrey J. Werner, Jeongmin Song, U. Werner-Zwanziger, J. W. Zwanziger, M. Grätzel, F. J. DiSalvo, Ulrich B. Wiesner. 2012. "A silica sol-gel design strategy for nanostructured metallic materials." Nature Materials 11 (5): 460-467.
Selected Awards and Honors
- Elected PMSE Fellow (American Chemical Society) 2015
- Cornell Engineering Research Excellence Award (Cornell University) 2015
- EMD Millipore Scientific Advisory Board Member 2015
- Plenary Lecturer (International Mesostructured Materials Symposium, IMMS9, Brisbane, Australia) 2015
- Plenary Speaker (3rd International Symposium: Frontiers in Polymer Science) 2013
- Diploma (Chemistry), Johannes Gutenberg University of Mainz, 1988
- Ph D (Physical Chemistry), University of Mainz and Max-Planck-Institute for Polymer Research, 1991