Dr. Yuting Li
Education
Ph.D. Polymer Chemistry Nankai University			Sep. 2000 Tianjin, P. R. China
Bachelor of Chemistry Nankai University			July 1994 Tianjin, P. R. China
Research Interests
· Reversible Addition-Fragmentation Chain Transfer Polymerization (RAFT). · ‘Smart’, stimuli-responsive water soluable polymers. · Block copolymer self assembly · Controlled Drug Delivery.
Current Research
Post-Doctoral Research Fellow	Supervisor: Professor Charles L. McCormick			February. 2005 – December. 2006
My research involves the synthesis of stimuli-responsive water soluble AB or ABC block copolymers by Controlled/ “Living” Radical Polymerization, namely Reversible Addition-Fragmentation Chain Transfer Polymerization (RAFT), and study their self-Assembly behaviour. In aqueous solution at room temperature these block copolymer chains exist as unimers but form micelles when the solution temperature is raised above the lower critical solution temperature. Incorporation of an active monomer N-acryloxysuccinimide into the triblock copolymer allows for facile formation of uniform shell cross-linked (SCL) micelles by reaction with ethylenediamine in aqueous media. When cystamine was used as the crosslinker, the cross-linking process is fully reversible: the cleaved SCL micelles can be reformed using cystamine as a thiol-exchange compound. These SCL micelles can be used as potential nanoscale carriers of active agents for targeted drug delivery, personal care and pharmaceutical application.
Previous Research Experience
Department of Chemistry, University of Sheffield, Sheffield, U. K					August2004-February2005
Post-Doctoral Research Fellow		Supervisor: Professor Steven P. Armes
My research interests include the synthesis of branched polymers by oxyanionic polymerization. Here, ethylene glycol dimethacrylate [EGDMA] is used as a crosslinker for the oxyanionic polymerization of 2-(dimethylamino)ethyl methacrylate[DMA]. Very interestingly, we found that no gelation occurred, even at crosslinker contents as high as 25 mol %. These results are very different to those obtained using atom transfer radical polymerization (ATRP). Most likely, the EGDMA crosslinker undergoes intra-chain cyclisation within the polymer chain in addition to inter-chain cross-linking and that the extent of this side reaction is highly dependent on whether the reactive chain ends are anionic or radical in nature. Water soluble branched polymers can also be synthesized by Atom Transfer Radical Polymerization (ATRP) using a disulfide-based dimethacrylate (DSDMA) branching agent. Varying the proportion of the DSDMA produced a series of soluble branched polymers, provided that there was on average less than one branching agent per primary chain. The disulfide bond in the DSDMA branching agent was readily cleaved using either dithiothreitol or benzoyl peroxide. In both cases GPC analyses confirm that the fully degraded polymer has almost the same molecular weight distribution as a linear polymer reference synthesized by ATRP under the same conditions in the absence of any disulfide-based dimethacrylate branching agent. Thus the primary chains are well-defined and have the Mn and Mw values predicted for a well-controlled ATRP synthesis, as expected.
Department of Chemistry, University of Sussex,  Brighton, U.K					April 2002- August 2004
Post-Doctoral Research Fellow		Supervisor: Professor Steven P. Armes
My research involves the direct polymerization of a cationic, quaternized monomer via ATRP. The polymerization of MeDMA is only poorly controlled in water and transesterification, apparently catalyzed by the Cu(I) complex, is a significant problem in methanol/water mixtures. The best control was achieved in a 1:1 isopropanol/water mixture at 20 ^oC at a MeDMA concentration of 20 to 30 w/v %. Although non-linear kinetic plots were observed even under these optimized conditions, low final polydispersities (Mw/Mn < 1.25) were obtained and chain extension experiments confirmed good blocking efficiencies. A number of new, well-defined cationic diblock copolymers were readily synthesized using either the macro-initiator approach or sequential monomer addition. My research also includes the synthesis of stimulus-responsive biomimetic star diblock copolymers. These copolymers can form either pH responsive or thermal responsive hydrogels at concentrations as low as 5.0 w/w %. The gels formed by varying the solution temperature were transparent, whereas gels formed by pH modulation were generally translucent due to trapped air bubbles. Rheological studies confirmed that the thermo-responsive star diblock gelators undergo a temperature-induced transition from a viscoelastic fluid to form an elastic solid.
Collaborators Professor Steven P. Armes University of Sheffield, Sheffield, UK
Selected Publications Yuting Li, Brad S. Lokitz, Steven P. Armes, Charles L. McCormick Manuscript in preparation. Yuting Li, Charles L. McCormick, Chapter in ACS book edited by Dr. Sarah E. Morgan. Submitted January 2006. Li, Yuting; Lokitz, Brad S.; McCormick, Charles L. Macromolecules 2006; 39(1); 81-89. Li, Yuting; Armes, Steven P. Macromolecules (2005), 38(20), 8155-8162. Li, Yuting; Tang, Yiqing; Narain, Ravin; Lewis, Andrew L.; Armes, Steven P. Langmuir (2005), 21(22), 9946-9954. Li, Yuting; Armes, Steven P. Macromolecules (2005), 38(12), 5002-5009. Houillot, Lisa; Nicolas, Julien; Save, Maud; Charleux, Bernadette; Li, Yuting; Armes, Steven P. Langmuir (2005), 21(15), 6726-6733. Jia, Yimei; Gray, Graham M.; Hay, John N.; Li, Yuting; Unali, Gian-Franco; Baines, Fiona L.; Armes, Steven P. Journal of Materials Chemistry (2005), 15(22), 2202-2209. Li, Yuting; Narain, Ravin; Ma, Yinghua; Lewis, Andrew L.; Armes, Steven P. Chem.Comm., 2004, (23), 2746-2747. Webber, Grant B.; Wanless, Erica J.; Armes, Steven P.; Tang, Yiqing; Li, Yuting; Biggs, Simon. Advanced Materials 2004, 16(20), 1794-1798. Amalvy J. I., Wanless E. J., Li Y., Michailidou V., and Armes S. P. Langmuir, 2004, 20(21); 8992-8999 Amalvy, J. I.; Unali, G. F.; Li, Y.; Granger-Bevan, S.; Armes, S. P.; Binks, B. P.; Rodrigues, J. A.; Whitby, C. P.; Langmuir 2004, 20(11), 4345 Langmuir, 2004, 20, 4345. Li, Yuting; Armes, Steven P.; Jin, Xiaoping; Zhu, Shiping. Macromolecules (2003), 36(22), 8268-8275.