Research Projects Summary

Major Theme:

Interdisciplinary research areas between chemistry and materials science.  Development of new polymerization approaches for the synthesis of functional polymers (electro-optical polymers and biocompatible polymers).  Synthesis and characterizations of molecular electronic components.  New surface reactivity and supramolecular assembly approaches for self-assembly of nanostructured materials.

Current Research Interests:

1. Molecular Electronics. Back to Top

It is well known that the extended p-electronic systems of conjugated polymers give the materials numerous physical properties, which resemble those of a typical inorganic semiconductor. For example, high electric conductivity after chemical doping, optical nonlinearity and electroluminescence has been demonstrated in the past decades. It will be very interesting if one can synthesize conjugated diblock copolymers. A fundamental question can be asked: what kind of electronic and structural properties will these rod-rod types of diblock copolymers exhibit? For example, if an electron-deficient conjugated block is coupled together with an electron-rich block, will the resultant diblock molecule behave like molecular p-n junction? The exploration of these diblock copolymers, their self-assembly behavior, and associated physical properties may lead to new physical phenomena, such as rectifying effect and optical switching. Careful engineering of these molecules, both in their amphiphilic properties andelectronic properties will allow us to organize these molecules into large area monolayers that may prove to be crucial for the realization of molecular electronic devices.  These materials present the unlimited opportunity to further fundamental knowledge of the electronic and structural properties of organic electroactive materials.

Strategy:

A two-stage approach: 1). Stepwise synthesis of conjugated oligomers with the proper functionality 2). Coupling with a living polymer species. 3) Thiol-gold linkage and isocyanide-nickel linkage.

Selected Publications:

1. W. J. Li, T. Maddux and L. P. Yu, “Syntheses of Oligothiophene with Defined Regiospecificity and Molecular Weights and Its Diblock Copolymers”, Macromolecules, 29, 7329, (1996).

2. T. Maddux, W. J. Li and L. P. Yu, "Stepwise Synthesis of Substituted Oligo(phenylene-vinylene) via an Orthogonal Approach", J. Am. Chem. Soc. 119, 844, (1997).

3. W. J. Li, H. B. Wang, L. P. Yu, T. L. Morkved and H. M. Jaeger, Syntheses of Oligophenylenevinylenes-Polyisoprene Diblock Copolymers and Their Microphase Separation ", Macromol., 32, 3034-3044, (1999).

4. V. S. Urban, H. H. Wang, P. Thiyagarajan, K. C. Littrell, H. B. Wang and L. P. Yu, Self-Organization of OPV-PEG Diblock Copolymers in THF / Water, J. Appl. Crystalgraph. 33, 645-649, (2000).

5. H. B. Wang, H. H. Wang, V. S. Urban, P. Thiyagarajan, K. C. Littrell, L. P. Yu, Syntheses of Amphiphilic Diblock Copolymers Containing a Conjugated Block and Their Self-Assembling Properties, J. Am. Chem. Soc., 122, 6855-6861, (2000).

6. H. B. Wang, M.-K. Ng, L. M. Wang and L. P. Yu, Conjugated Diblock Copolymers, Chemistry - A European Journal, 8, 3246-3253, (2002).

7. M.-K. Ng, and L. P. Yu, Synthesis of Amphiphilic Conjugated Diblock Oligomers As Molecular Diodes, Angew. Chem. Int. Ed., 41, 3598-3601, (2002)

8. M.-K. Ng, D. C. Lee & L. P. Yu, Molecular Diodes Based Upon conjugated Diblock Co-oligomers, J. Am. Chem. Soc., 124(40), 11862-11863, (2002).

9. P. Jiang, G. M. Morales, W. You, & L.P. Yu, Synthesis of Diode Molecules and Their Sequential Assembly to Control Electron Transport Angew. Chem. Int. Ed. 43, 4471-4475, (2004).

10. G. M. Morales, P. Jiang, S. Yuan, Y. Lee, A. Sanchez, W. You, & L. P. Yu, Inversion of the Rectifying Effect in Diblock Molecular Diodes by Protonation, J. Am. Chem. Soc., 127, 10456-10457, (2005).

11. Lee, Youngu; Morales, Gustavo M.; Yu, Luping. Self-assembled monolayers of isocyanides on nickel electrodes. Angew. Chem., Int. Ed., 44(27), 4228-4231,(2005).

2. Functional Polymers Containing Metal Complexes. Back to Top

Metal complexes exhibit rich electro-magnetic and optical properties, which can be explored for electro-optic materials. One of our projects is to combine organic conjugated polymers with transition metal complexes to investigate new physical properties. Introduction of transition metal ions into p-conjugated polymers provides enormous opportunities to tune the physical properties of the resulting materials. From the strong interaction between transition metal complexes and conducting polymer backbones, unique photophysical, photochemical and electrochemical properties are expected to evolve, leading to materials with a wide range of interesting physical properties, such as photorefractive effects, photoconductivity and novel redox property. These polymers exhibit promising potential for applications in solar energy conversion, sensors, polymer-supported electrodes, nonlinear optics, photorefraction and electroluminescence.

Figure 3. Conjugated polymers containing neutral ruthenium complexes.

Selected Publications:

1. Z. N. Bao and L. P. Yu, New Matalloporphyrin Containing Polymers from the Heck Coupling Reactions, Macromolecules, 27, 4629, (1994).

2. Z. H. Peng and L. P. Yu, Synthesis of Conjugated Polymers Containing Ionic Transition Metal Complexes, J. Am. Chem. Soc., 118, 3777, (1996).

3. Z. H. Peng, A. R. Gharavi and L. P. Yu, Synthesis and Characterization of Photorefractive Polymers Containing Transition Metal Complexes as Photosensitizer, J. Am. Chem. Soc., 119, 4622, (1997).

4. Q. Wang, L. M. Wang, and L. P. Yu, Synthesis and Unusual Physical Behavior of A Photorefractive Polymer Containing Tri(bispyridyl) Ruthenium(II) Complexes as Photosensitizer and Exhibiting a Low Glass-Transition Temperature, J. Am. Chem. Soc., 120, 12860, (1998).

5. Q. Wang and L. P. Yu, Conjugated Polymers Containing Mixed-ligand Ruthenium(II) Complexe: Synthesis, Characterization and Investigation of Photoconductive Properties, J. Am. Chem. Soc., 122, 11806, (2000).

3. Photo-induced Electron Transfer and Photovoltaic Materials. Back to Top

Update soon

1. Chen, Lin X.; Xiao, Shengqiang; Yu, Luping. Dynamics of Photoinduced Electron Transfer in a Molecular Donor-Acceptor Quartet. J. Phys. Chem. B, 110(24), 11730-11738, (2006).

4. Gene Transfer Polymer. Back to Top

Update soon.

5. Hydrogen Storage Polymer. Back to Top

Update soon.

Previous Research Projects:

Polymer Chemistry

1.Polymerization Methodology. Back to Top

Since many of the polymer systems designed in our group contain manyfunctional groups, which are incompatible with many polymerization reactions, the preparation of most of them needs new chemical approaches.  We are especially interested in exploring reactions that require mild reaction conditions.  Typical examples include: a). palladium-mediated coupling reactions (the Heck reaction, the Stille coupling reaction) for the preparation of conjugated polymers; b).  the Mitsunobu reactions for the preparation of electro-optic polymers; c).  living ring-opening polymerization for the synthesis of biocompatible polyesters; d).  chemoselective ligation for the preparation of biocompatible diblock copolymers; e). orthogonal approach for the synthesis of well-defined oligo-phenylenevinylenes.

Applications for Syntheses of

Conjugated photorefractive polymers.

Conjugated photorefractive polymers containing ionic species.

Conjugated liquid crystalline polymers and oligomers.

Conjugated polymers with liquid crystalline side chains.

Phenylenevinylene dendritic molecules.

a. Palladium-mediated polycondensations.

Figure 1. Conjugated photorefractive polymers.

Figure 2: Conjugated photorefractive polymers containing ionic ruthenium and osmium complexes, synthesized from the Heck reaction.

Figure 3. Conjugated liquid crystalline polymers.

Figure 4. Examples of conjugated polymers functionalized with mesogenic side chains.

By utilizing both the Heck and Horner-Wadsworth-Emmons reactions, an orthogonal approach was developed towards the stepwise synthesis of end-functionalized oligo-phenylenevinylenes (OPV). Because of the mutual compatibility of the functional groups involved in both reactions, no protecting group chemistry was needed. These OPV molecules showed liquid crystallinity. The funtionalized OPVs can be further coupled with other functional polymers to form diblock copolymers. 

Figure 5: An orthogonal approach to the synthesis of OPV.

Selected Publications:

1. W. K. Chan, Y. M. Chen, Z. H. Peng and L. P. Yu, Rational Designs of Multifunctional Polymers, J. Am. Chem. Soc., 115, 11735, (1993).

2. Z. N. Bao, W. K. Chan, L. P. Yu, Synthesis of Electroactive Polymers by the Stille Coupling Reaction, Chem. Mater., 5, 2, (1993).

3. Z. N. Bao, Y. M. Chen, and R. B. Cai, L. P. Yu, Conjugated Liquid Crystalline Polymers-Soluble and Fusible Poly(phenylene vinylene) by the Heck Coupling Reaction, Macromolecules, 26, 5281, (1993).

4. Z. N. Bao, L. P. Yu, Polymers Containing Metalloporphyrins, Synthesis, Characterization and Physical Properties,Trends in Polymer Science, 3, 159, (1995).

5. Z. N. Bao, W. K. Chan and L. P. Yu, Exploration of the Stille Coupling Reaction for the Synthesis of Functional Polymers, J. Am. Chem. Soc., 117, 12426, (1995).

6. M. Pan, Z. N. Bao and L. P. Yu, Regiospecific, Functionalized Poly(phenylene vinylene) from the Heck Coupling Reaction, Macromolecules, 28, 5151, (1995).

7. L. P. Yu, Progress in Organic Chemistry Towards Syntheses of Multifunctional Polymers, Youji Huaxue, 17, 69, (1997).

8. M. Samoc, A. Samoc, B. Luther-Davies, Z. N. Bao, L. P. Yu, S. K. Deb, B. Hsieh and U. Scherf, Prospects of Third Order Nonlinear Optical Polymers for Guided Wave Applications, Rigid Rod, Hairy Rod, Ladder and Picket Fence Polymers, MCLC S&T, Nonlinear Optics, 20, 183, (1999).

b. Living ring-opening polymerization of cyclic lactone to form thioester-functionalized polyesters for chemo-ligation.

We have demonstrated a new initiator system which initiates the polymerization of cyclic lactone in a living fashion. At the same time, a thioester functional group is introduced into the polyester terminal allowing for further chemical manipulation (such as chemo-ligation) to prepare bioactive diblock copolymers. These materials are interesting for drug delivery and other biocompatible studies.

Figure 6. Synthesis of bioactive polyesters and related diblock copolymers.

Selected Publications:

9. Q. Ni and L. P. Yu, Synthesis of Novel Poly(e-caprolactone)s Functionalized with a Thioester End-Group via A Living Ring Opening Polymerization and Their Application in Chemoselective Ligation with Compounds Containing A Cysteine Terminal, J. Am. Chem. Soc., 120, 1645, (1998).

10. Q. Ni and L. P. Yu, Synthesis of Thioester End-Functionalized Poly(e-Caprolactone) and Its Application in Chemoselective Ligation, in Tailored Polymeric Materials for Controlled Delivery System, ACS Symposium Ser.,709, 92-104, (1998).

2. Photorefractive and Electro-Optic Polymers. Back to Top

The pursuit of research of photorefractive polymers is driven by both the fundamental challenge in identifying the basic synthetic principles of these multi-functional polymers and their potential for practical applications, such as for optical signal processing and information storage. Organic photorefractive (PR) materials are a new kind of electro-optic material, which possess both electro-optic effect and photoconductivity. It is a challenge to integrate these properties into a single polymer system that will exhibit this PR effect. This project involves a great deal of organic synthesis of new polymer structures. These new structures are designed based on our current understanding and synthesized and characterized to test our new hypothesis.

Strategies:

To synthesize fully functionalized, single-chain multifunctional polymers so that phase separation can be avoided.

To utilize conjugated polymer backbones to play three roles: (1) charge generation, (2) charge transport and (3) charge trapping. To covalently attach the NLO chromophore to the backbone as to show PR effect. 

To synthesize conjugated polymers containing a ruthenium complex and second order nonlinear optical chromophores. To utilize the metal-to-ligand charge transfer properties of tribispyridinyl ruthenium complexes in order to enhance the photorefractive performance.

To synthesize multifunctional molecules which form amorphous films to demonstrate PR effect.

 Figure 1. Conjugated photorefractive polymers with a porphyrin unit as the charge generating species.

Figure 2. Photorefractive polymers utilizing the principles of photosynthetic model compounds.

Figure 3. A high performance multifunctional photorefractive molecule.

Physical Studies:

Photoconductivity, charge mobility, electro-optic coefficients, second harmonic generation, two beam coupling measurements and diffraction efficiency measurements using four wave-mixing techniques.

Selected Publications:

(a) photorefractive materials:

1. L. P. Yu, W. K. Chan, Z. N. Bao and S. Cao, "Photorefractive Polymer-Synthesis and Mechanism", Chem. Commun., 1735, (1992).

2. L. P. Yu, W. K. Chan, Z. N. Bao and S. Cao,  "Photorefractive Polymer 2-Structural Design and Property Characterization", Macromolecules, 26, 2216, (1993).

3. Y. M. Chen, Z. H. Peng, W. K. Chan and L. P. Yu, "A New Photorefractive Polymer Based on Multifunctional Polyurethane", Appl. Phys. Lett., 64, 1195, (1994).

4. L. P. Yu, Y. M. Chen, W. K. Chan and Z. H. Peng, "Conjugated Photorefractive Polymers", Appl. Phys. Lett.,  64, 2489, (1994).

5. Z. H. Peng, Z. N. Bao, Y. M. Chen, L. P. Yu, Large Photorefractivity in an Exceptionally Thermo-Stable Multifunctional Polyimide, J. Am. Chem. Soc., 116, 6003, (1994).

6. L. P. Yu, Y. M. Chen, W. K. Chan, Detailed Studies on a New Conjugated Photorefractive Polymer, J. Phys. Chem., 99, 2797, (1995).

7. W. K. Chan, L. P. Yu, Studies of Functionalized Poly(Phenylenevinylene)s, Macromolecules, 28, 6410, (1995).

8. L. P. Yu, W. K. Chan, Z. H. Peng, A. R. Gharavi, Multifunctional Polymers Exhibiting Photorefractive Effects, Acc. Chem. Res., 29, 13, (1996).

9. L. P. Yu, W. K. Chan, Z. H. Peng, W. J. Li, A. R. Gharavi, Photorefractive Polymers, Invited book chapter in organic Conductive Molecules and Polymers, Ed. H. S. Nalwa. John Wiley and Sons, New York, Vol. 4, Chapter 5, 233, (1997).

10. Z. H. Peng, A. R. Gharavi, L. P. Yu, Hybridized Approach to New Polymers Exhibiting Large Potorefractivity, Appl. Phys. Lett.,  69, 4002, (1996).

11. W.J. Li, A. R. Gharavi and L. P. Yu, Photorefractive Molecule Containing oligo(3-hexylthiophene) and A Nonlinear Optical Chromophore, Adv. Mater.10, 927, (1998).

12. L. M. Wang, Q. Wang, and L. P. Yu, The Effect of a Local Field on Photogeneration Efficiency in a Novel Photorefractive Polymer, Appl. Phys. Lett., 73, 2546, (1998).

13. Q. Wang, L. M. Wang, H. A. Saadeh and L. P. Yu, A New Family of Amorphous Molecular Materials Showing Large Photorefractive Effect, Chem. Commun., 1689, (1999).

14. Q. Wang, L. M. Wang and L. P. Yu, Development of Fully Functionalized Photorefractive Polymers, Macromol. Rapic Commun., 21, 723, (2000).

15. L. M. Wang, M.-K. Ng and L. P. Yu, Complementary Holographic Gratings Through Electron-Hole Transport In A Fully Functionalized Photorefractive Molecular Glass, Phys. Rev. B., 62, 4973, (2000).

16. Q. Wang, L. M. Wang, J. J. Yu, and L. P. Yu, Syntheses of Novel Photorefractive Polymers and the Structural Effects of Transition Metal Phthalocyanine and Porphyrin Complexes on Photorefractive Performances, Adv. Mater. 12, 974, (2000).

17. J. J. Yu, L. M. Wang, Q. Wang, M.-K. Ng and L. P. Yu, Picosecond Optical limiting Performance of A Novel PPV-ZnPc Conjugated Polymer, J. Nonlinear Optical Physics-Materials, 9, 289, (2000).

18. M.-K. Ng, L. M. Wang, H. A. Saadeh, and L. P. Yu, Photorefractive Effects and Structure/Property Correlation of Oligothiophenes Functionalized With Nonlinear Optical Chromophores, Chem. Mater. 12, 2988, (2000).

19. L. M. Wang, M.-K. Ng, and L. P. Yu, The Simpler, The Better---Single Molecular Photorefractive Materials Based On Methine Dyes, Appl. Phys. Lett., 78, 700, (2001).

20. Q. Wang, L. P. Yu, Fully functionalized photorefractive materials Containing Transition Metal Complexes as the Photosensitizers, Polymer News, 26, 113, (2001).

21. L. P. Yu, Lesson Learned From Researcon On Photorefractive Organic Polymers and Molecular Materials, J. Polym. Sci. Part A: Polym. Chem. 39, 2557, (2001).

22. W. You, L. M. Wang, Q. Wang and L. P. Yu, Synthesis and Structure/Property Correlation of Fully Functionalized Photorefractive Polymers, Macromolecules, 35, 4636, (2002).

23. M.-K. Ng, W. You, L. M. Wang, and L. P. Yu, Multifunctional Methine Dyes as Efficient Photorefractive Materials, J. Am. Chem. Soc. Submitted.

24. L. P. Yu, W. K. Chan, S. Dikshit, Z. N. Bao, Y. Q. Shi and W. Steier, Thermally Curable Second Nonlinear Optical Polymers, Appl. Phys. Lett., 60, 1655, (1992).

25. L. P. Yu, W. K. Chan, and Z. N. Bao, Synthesis and Characterization of Thermally Curable Second Nonlinear Optical Polymers, Macromolecules, 25, 5609, (1992).

26. Z. H. Peng, L. P. Yu, Second Order Nonlinear Optical Polyimide With High Temperature Stability, Macromolecules, 27, 2638, (1994).

27. S. Y. Yang, Z. H. Peng, L. P. Yu, Functionalized Polyimides Exhibiting Large and Stable Second Order Optical Nonlinearity, Macromolecules, 27, 5858, (1994).

28. D. Yu and L. P. Yu, Functionalized Aromatic Polyimide for Second Order Nonlinear Optics,Macromolecules, 27, 6718, (1994).

29. D. Yu, A. Gharavi and L. P. Yu, A Generic Approach To Functionalizing Aromatic Polyimides for Second Order Nonlinear Optics, Macromolecules, 28, 784, (1995).

30. D. Yu, A. Gharavi and L. P. Yu, Novel Aromatic Polyimides for Nonlinear Optics, J. Am. Chem. Soc., 117, 11680, (1995).

31. D. Yu, A. Gharavi and L. P. Yu, New Second Order Nonlinear Optical, Aromatic and Aliphatic Polyimides Exhibiting High Temperature Stability, Appl. Phys. Lett., 66, 1050, (1995).

32. D. Yu, A. Gharavi and L. P. Yu, Highly Stable Copolyimides for Second Order Nonlinear Optics, Macromolecules, 29, 6139, (1996).

33. H. Saadeh, A. Gharavi, T. Goodson and L. P. Yu, Polyimide Exhibiting High Thermal Stability and Large Electro-optic Coefficient, Macromolecules, 30, 5403, (1997).

34. D. Yu, W. J. Li, A. Gharavi and L. P. Yu, Highly Stable Copolyimides for Second Order Nonlinear Optics, in Photonic and Optoelectronic Polymers, Eds. S. A. Jenekhe and K. J. Wynne, ACS Symposium Series 672, ACS Washington D.C., pp123-132, (1997).

35. M. Samoc, A. Samoc, B. Lurher-Davies, Z. N. Bao, L. P. Yu, B. Hsieh and U. Scherf, Femtosecond Z-scan and Degenerate Four Wave-Mixing Measurements of the Real and Imaginary Part of the Third Order Nonlinearity of Soluble Conjugated Polymers, J. Opt. Soc. Am B 15: (2) 817-825, (1998).

36. H. Saadeh, D. Yu, L. M. Wang, and L. P. Yu, Highly Stable, Functionalized Polyimides for Second Order Nonlinear Optics, J. Mater. Chem., 9, 1865, (1999).

37. H. A. Saadeh, L. M. Wang and L. P. Yu, A New Synthetic Approach To Novel Polymers With a Pending NLO Chromophore Exhibiting Large Value But High Chemical Sensitivity, Macromolecules, 33, 1570, (2000).

38. H. A. Saadeh, L. M. Wang and L. P. Yu, Supramolecular Solid State Assemblies Exhibiting Electro-Optic Effects, J. Am. Chem. Soc., 122, 546, (2000).

3. High Performance LED from Well Defined Conjugated Oligomers. Back to Top

This work was initiated in conjunction with our project on conjugated diblock copolymers. The OPVs mentioned above can be spin-cast into uniform films and thus offered us a unique opportunity to study their LED properties. These LED elements exhibit a relatively higher quantum efficiency (1.3% in a single-layered structure) and a longer life-time than their polymeric counterparts because of their uniform molecular weight and high purity.

Figure 1. Structures of Oligo-phenylenevinylene and the light emitting device.

Selected Publications:

1. T. Goodson, W. J. Li and L. P. Yu, Oligo(phenylenevinylene) for Light Emitting Diodes, Adv. Mater., 9, 639, (1997).

2. H. A. Saadeh, T. Goodson and L. P. Yu, Synthesis and Electroluminescent Studies of Poly(phenylene-co-furane) and Poly(phenylene-co-thiophene), Macromolecules, 30, 4608, (1997).

4. Conjugated Liquid Crystalline Polymers. Back to Top

Liquid crystallinity and delocalized p-conjugate systems are an ideal combination in the study of new structural properties and electronic properties of conjugated polymers. The significance of this work is that it will provide fundamental knowledge about the structural properties of conjugated polymers.  The physical properties of conjugated polymers can be enhanced by the unique ordering effect caused by the liquid crystallinity.

Strategies:

Utilizing the Stille and the Heck reactions to synthesize soluble and fusible conjugated polymers and oligomers.

Figure 2. Conjugated liquid crystalline polymers (intended for photorefractive effects).

Physical Studies:

Cross polarized microscopy, DSC, x-ray diffraction, photoconductivity, third order NLO coefficients and NMR relaxation time (T1).

Future work

Systematic synthesis of a series of these polymers. Structure/property relationship. Magnetic field effects on alignments and physical properties.

Selected Publications:

1. Q. Wang and L. P. Yu, Conjugated Polymers Containing Mixed-ligand Ruthenium(II) Complexes. Synthesis, Characterization and Investigation of Photoconductive Properties, J. Am. Chem. Soc., 122, 11806, (2000).

2. L. P. Yu, Z. N. Bao and R. B. Cai, Conjugated Liquid Crystalline Polymers, Angew. Chem. Int. Ed. Engl., 32, 1345, (1993).

3. L. P. Yu and Z. N. Bao, Conjugated Polymers Exhibiting Liquid Crystallinity, Advanced Materials, 6, 156, (1994).

4. W. Zhu, W. J. Li and L. P. Yu, Investigation of the Liquid Crystalline-Isotropic Phase Transition in Oligo(phenylenevinylene), Macromolecules, 30, 6274, (1997).

5. Architectural controls of polymer microstructures. Back to Top

To synthesize functional polymers with better controls in either stereochemistry or architectural structures or both.  To enhance physical properties or even to observe new physical properties, through careful designs and synthesis of the new monomers and polymers.  These dendritic molecules form amorphous solids and can be used as optical materials.  For example, photorefractive molecules can be prepared by attaching NLO chromophores outside and a photosensitizer in the core of the dendrimer.  Other applications will also be explored.

Selected Publications:

1. T. Maddux, W. J. Li and L. P. Yu, Stepwise Synthesis of Substituted Oligo(phenylene-vinylene) via an Orthogonal Approach, J. Am. Chem. Soc. 119, 844, (1997).

2. S. Deb, T. Maddux and L. P. Yu, A Simple Orthogonal Approach to Phenylenevinylene Dendrimers, J. Am. Chem. Soc., 119, 9079, (1997).

Surface Chemistry

6. Supramolecular Assembly of Nanostructured Materials. Back to Top

Research on nanostructured materials is the new frontier in materials science.  A challenging task in this area is to manipulate nanostructured materials and assemble them into desired structural forms-one, two or three-dimensional structures so that the unique physical properties associated with nanostructured materials can be harvested.  Organic chemistry plays a crucial role in the development of nanoscience and nanotechnlogy.  Supramolecular assembly of nanostructured materials is the key to the success.  We are developing new supramolecular approaches to assemble nanoclusters into one, two or three-dimensional structures.  The new approaches also allow us to prepare ultrathin polymer films with functions such as electro-optic effects, biomedical properties and biosensor applications.

Selected Publications:

1. E. Chan and L. P. Yu, Chemoselective immobilization of Gold Nanonanoparticles onto Self-Assembled Monolayers, Langmuir, 18, 311, (2002).

2. E. Chan, D.-C. Lee, M.-K. Ng, G. Wu, K. Y. C. Lee, and L. Yu, A Novel Layer-by-Layer Approach to Immobilization of Polymers and Nanoclusters, J. Am. Chem. Soc., 124(41), 12238-12243, (2002).