|Academic Profile |
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Dr Loo Sun Sun Leslie
Division of Chemical and Biomolecular Engineering
School of Chemical and Biomedical Engineering
College of Engineering
Phone: (+65)6790 6737
- BS(ChemEng)(Summa cum Laude) Rice University 1994
- PhD Massachusetts Institute of Technology 2000
|*** Visit my website at http://www3.ntu.edu.sg/home/ssloo
Dr. Leslie Loo has been in the School of Chemical and Biomedical Engineering since 2004. He received his Bachelor degree in Chemical Engineering from Rice University and Ph.D. degree from MIT. His research interests include polymer nanocomposites and spectroscopy.
|Our group has been interested in studying the role of molecular structure and dynamics upon the properties of polymers and polymer nanocomposites. Organic-inorganic hybrid nanocomposites have shown potential for a wide range of applications due to their enhanced mechanical, thermal and electrical properties. However, while many hybrid systems have been characterized and properties evaluated, much current work is not systematic and addresses only macroscopic issues. There is still little understanding of how to put together an optimal organic-inorganic combination which will achieve a certain enhancement in nanocomposite properties. This is evidenced by the fact that not all nanocomposites demonstrated improvement in properties due to a lack of understanding of the basic interactions at the organic-inorganic interface. To date the nature of this interface is not well-characterized.
We have formulated our research thrusts in two different aspects: one is through the use of spectroscopic techniques and the other is through the fundamental study of molecular interactions at interfaces. In the first area, spectroscopic techniques are important for investigating molecular and surface properties at the nanoscale level. The nanoscale dimensions of the nano-particles require the use of instruments which can probe the nanoscale interactions between the particles and the polymer matrix. Spectroscopic techniques allow the discrimination of inter- and intra- molecular forces that exist between polymer and nanofillers. Furthermore, the strength of such interactions can also be studied. The use of solid state nuclear magnetic resonance (NMR) spectroscopy has allowed us to demonstrate the enhanced mobility of polymer chains during active tensile deformation (Loo et al., Science 2000). We have also employed Fourier transform infrared spectroscopy to elucidate the mechanics of deformation and thermal degradation in polymer nanocomposites (Zhang and Loo, Polymer 2009; Loo and Gleason, Macromolecules 2003).
In the second area, we have formulated model systems in which we can better ascertain the role played by interfaces in affecting the performance of polymer nanocomposites. Recently, we have demonstrated with our model system of the different effectiveness of nano-fillers in enhancing the mechanical properties of fully amorphous versus semi-crystalline polymers (Zhang and Loo, Macromolecules 2009). We have also succeeded in using Langmuir-Blodgett technique to deposit layered silicate onto a polymeric surface and studied its properties (Zhou and Loo, accepted by J. Colloid & Interface Sci. 2009).
From our work, we endeavour to produce organic-inorganic nanocomposites with better properties by intelligent manipulation of the interfacial interactions. This will have a great impact on the design of new materials with novel applications.
- Xu, D; Loo, LS; Wang, K. (2013). Pervaporation Performance of Novel Chitosan-POSS Hybrid Membranes: Effects of POSS and Operating Conditions. Journal of Polymer Science. Part B, Polymer Physics, 48, 2185–2192.
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