Zhibin Guan

Professor, Chemistry
School of Physical Sciences

PH.D., University of North Carolina at Chapel Hill, 1994


B.S. 1987 and M.S. 1990, Peking University

Phone: (949) 824-5172
Fax: (949) 824-2210
Email: zguan@uci.edu

University of California
5042D Frederick Reines Hall
Mail Code: 2025
Irvine, CA 92697

1. Polymer Architecture Design through Catalysis - The goal of this research is to develop transition metal-catalyzed highly efficient synthesis of polymers having complex architectures and functionalities. We have recently discovered that by controlling the relative rates of chain propagation and chain walking, polymer architecture can be successfully tuned from linear to hyperbranched to "dendritic". We have applied this methodology to the one-pot syntheses of dendritic multi-functional polymers and amphiphilic molecular nanocarriers. These new materials are currently being explored as multivalent ligands for biological interactions, as new vectors for drug delivery, and as presentation scaffolds for drugs and antigens. We are also applying this catalyst strategy to the synthesis of core-shell dendritic polymers carrying different chromophores for photo-electronic applications.
   
   
   
   
   
   To augment our new materials design, we have been developing advanced transition metal catalysts for olefin polymerization. A recent breakthrough in our laboratory is the discovery of new cyclophane-based catalysts that show excellent activity and high thermal stability for olefin polymerization. We are currently developing a family of new cyclophane-based ligands for polymerization catalysis.
   
   
   
   
   
   
2. Biomimetic Supramolecular Polymer Designs - The goal of this research is twofold: (1) to design advanced polymeric materials having well-defined supramolecular structures by following the strategies observed in Nature; (2) to fundamentally understand the molecular mechanism for the macroscopic properties of polymeric materials. Recent single molecule studies of biological macromolecules have provided profound understanding to the molecular mechanisms by which Nature designs its advanced materials. This insight provides us fresh inspiration for novel materials design. In one project we followed the supramolecular design being used in the skeletal muscle protein, titin, to synthesize modular polymers containing multiple loops by using precise hydrogen bonding units. By using force probe microscopy, we have shown that the folded loops in a modular polymer are unfolded sequentially as a single polymer chain is stretched. Bulk mechanical tests demonstrate that this modular domain structure provides the molecular mechanism to successfully combine high mechanical strength, toughness and elasticity - three fundamental mechanical properties that are rarely found in one polymer. We are currently following a number of other biological model systems for the design of biomimetic polymeric materials having precise supramolecular structures for advanced properties.
   
   
   
   
   
   
3. New Biomaterials from Natural Building Blocks - The recent development of advanced medical and biotech applications has created a great demand for new biomaterials with tailor-made properties. A new research direction in our group is to develop new biomaterials from abundant natural building blocks such as carbohydrates and peptides. We have recently developed a carbohydrate-derived side-chain polyether that combines excellent protein resistance with biodegradability and functionalizability. Potential applications of this new biomaterial include drug delivery, biosensors, implanted devices, tissue regeneration, and protenomics. We have also developed a series of carbohydrate-peptide hybrid biopolymers as vectors for gene and drug delivery and currently we collaborate with biomedical researchers to explore new applications of our biomaterials.