主持美国 Virginia Tech大学化学系Prof. Guoliang Liu学术报告[合影] (2016.6.3)-Li-Ming Zhang

Block copolymers are versatile materials that have rich chemical and physical properties. Here I present the utilization of these materials to address challenges in two distinct fields. 1) In microelectronics, the size and density of patterned features determine the power of a device. The 2018 target for a microprocessor unit is 15.0 nm half-pitch, which is a daunting challenge in the semiconductor industry. My research focused on addressing this challenge by integrating directed assembly techniques with conventional lithography, where block copolymers were used to form densely-packed features as small as 13.5 nm. 2) In nanoparticle chemistry, it is challenging to synthesize patterned nanoparticles on a surface with control over size, shape, and composition. By integrating block copolymers with scanning probe lithography, my work demonstrates that single nanoparticles can be synthesized by precisely controlling the amount of metal precursors (Au, Ag, Pt, Pd, Fe, Co, Ni, or Cu) in each patterned polymer nanoreactor. The block copolymer significantly enhances the mobility of metal precursors, thereby mediating diffusion and coalescence of precursors to form single nanoparticles. This capability opens up the possibility of creating combinatorial nanoparticle libraries for catalyst screening. Lastly, I will extend the applications of these materials to energy and environmental sciences.

Biography:

Guoliang Liu received his B. S. in Chemical Engineering from Zhejiang University, P. R. China in 2005, and his Ph.D. degree in Chemical Engineering from the University of Wisconsin-Madison under the supervision of Prof. Paul F. Nealey in 2011. Before completing his Ph.D. degree, his research in block copolymer lithography was recognized by Hitachi GST (San Jose, California), and he was recruited to apply his findings in magnetic data storage in 2010. Afterwards, he conducted postdoctoral research at Northwestern University (advisor, Dr. Chad A. Mirkin), where he was named an Outstanding Researcher in the International Institute for Nanotechnology. He joined as an assistant professor in the Department of Chemistry and an affiliated professor in the Department of Chemical Engineering at Virginia Tech in Fall 2014. He is also an assistant professor of Nanoscience in the Academy of Integrated Science. He is affiliated to the Virginia Tech Center for Sustainable Nanotechnology and the Macromolecules and Interfaces Institute, a Macromolecular Science and Engineering program at Virginia Tech.

Selected Publications:

1.G. Liu, K. L. Young, X. Liao, M. L. Personick, C. A. Mirkin. Anisotropic nanoparticles as shape-directing catalysts for the chemical etching of silicon. Journal of the American Chemical Society, 2013, 135: 12196-12199.

2.G. Liu, Y. Zhou, R. Banga, Radha B., K. A. Brown, A. J. Chipre, S. T. Nguyen, C. A. Mirkin. The role of viscosity on the polymer ink transport in dip-pen nanolithography. Chemical Science, 2013, 4: 2093-2099.

3.G. Liu, D. J. Eichelsdoerfer, B. Rasin, Y. Zhou, K. A. Brown, X. Liao, C. A. Mirkin. Delineating the pathways for the site-directed synthesis of individual nanoparticles on surfaces. Proceedings of the National Academy of Science, 2013, 110: 887-891.

4.G. Liu, A. Ramirez-Hernandez, H. Yoshida, K. Nygard, D. K. Satapathy, O. Bunk, J. J. de Pablo, P. F. Nealey. Morphology of Lamellae-forming block copolymer films between two orthogonal chemically nanopatterned striped surfaces. Physical Review Letters, 2012, 108: 065502.

5.G. Liu, F. A. Detcheverry, A. Ramirez-Hernandez, H. Yoshida, Y. Tada, J. J. de Pablo, P. F. Nealey. Non-bulk complex structures in thin films of symmetric block copolymers on chemically nanopatterned surfaces. Macromolecules, 2012, 45: 3986-3992.