Functional Block Copolymers - Morphologies and Functionality

Block copolymers are one of the key structural platforms that can produce nanoscale (typically 10 – 100 nm) phase separations with cylindrical, lamellar, spherical, bicontinuous, micellar and vesicle morphologies. The morphologies can be tuned by changing the molecular weights and composition, as well as the asymmetry and interaction between the repeat units of the blocks. These nanostructures can be utilized as templates for controlling/growing of the inorganic and magnetic nano-particles and nano-rod with well-defined domains. The micellar and vesicle structures are also interesting because of their potential in drug and gene delivery.

The focus of our research in this area is on:

1) Incubating suitable electronic and optical properties into block copolymers;

2) Studying their functionality/nanostructure relationships;

3) Fine-tuning their functionality by forming one-, two-, or three-dimensional confinement of nanostructures for device applications.

The following are a few examples of functional block copolymers being used for photonic and sensing applications:

Electro-optical (E-O) block copolymers

• Enhance poling efficiency.
• Improve thermal stability without using cross-linking or high T g polymers.
• Reduce optical loss.

Fluorescent rod-coil block copolymers

• Solvent-stimulated nanostructures and photophysical properties.
• Temperature-stimulated nanostructures and functional properties.
• pH-stimulated nanostructures and optical functionality.
• Understanding nanostructure / functionality relationships

Relevant Refereed Papers

1. "2-(2’-Hydroxyphenyl)benzoxazole-containing Two-Photon Absorbing Chromophores as Sensors for Zinc and Hydroxide Ions", Y. Q. Tian, C.-Y. Chen, C.-C. Yang, A. C. Young, S.-H. Jang, W.-C. Chen, A. K.-Y. Jen, Chemistry of Materials, 2008, 20(5); 1977-1987.
2. "Hydrophobic Chromophores in Aqueous Micellar Solution Showing Large Two-photon Absorption Cross-sections", Y. Q. Tian, C.-Y. Chen, Y.-J. Cheng, A. C. Young, N. M. Tucker,  A. K.-Y. Jen, Adv. Funct. Mater., 2007, 17, 1691-1697.
3. "Nanostructured Functional Block Copolymers for Electro-Optic Devices", Y. Q. Tian, C.-Y. Chen, M. A. Haller, N. M. Tucker, J.-W. Ka, J. D. Luo, S. Huang, A. K.-Y. Jen, Macromolecules, 2007, 40(1), 97-104.
4. "Two-photon Absorbing Block Copolymer as a Nanocarrier for Porphyrin - Energy Transfer and Singlet Oxygen Generation in Micellar Aqueous Solution", C.-Y. Chen, Y. Q. Tian, Y.-J.  Cheng, A. C. Young, J.-W. Ka, A. K.-Y. Jen, J. Am. Chem. Soc., 2007, 129 (23), 7220-7221.
5. "Cross-Conjugated Polymers with Large Two-Photon Absorption Cross-sections for Metal Ion Sensing", F. Huang, Y. Q. Tian, C.-Y. Chen, Y.-J. Cheng, A. C. Young, A. K.-Y. Jen, J. Phys. Chem. C, 2007, 111(28), 10673-10681.
6. "New 2-(2-Hydroxyphenyl)benzoxazole-containing Poly(N-isopropylacrylamide) Copolymer as pH, Zinc  ion and Temperature Sensor", C.-C. Yang, Y. Q. Tian, C.-Y. Chen, A. K.-Y. Jen, W.-C. Chen, Macromol. Rapid. Commun., 2007, 28, 894-899.
7. "Theoretical and Experimental Studies on the Surface Structures of Conjugated Rod-Coil Block Copolymer Brushes", W.-C. Wu, Y. Q. Tian, C.-Y. Chen, C.-S. Lee, Y.-J. Sheng, W.-C. Chen, A. K.-Y. Jen, Langmuir, 2007, 23(5), 2805-2814.
8. "New Environmental-Responsive Fluorescent NIPAA Copolymer and Its Application on DNA Sensing", C. C. Yang, Y. Q. Tian, A. K.-Y. Jen, W. C. Chen, J. Polym. Sci. Polym. Chem., 2006, 44, 5495-5504.