ABC Block Copolymer-Nanoparticle Co-Assemblies

1. + ABC Block Copolymer-Nanoparticle Co-Assemblies Ulrich Wiesner, Cornell University, DMR 0605856 PEP–b–PEO–b–PHMA + sol In analogy to the biological protein machinery, the monomer (block) sequence information of synthetic, non-natural macromolecules can be used to encode information about molecular level structure and functionality of co-assemblies with dissimilar materials like, e.g., ceramics. This may lead to the design of entirely new classes of materials with properties that have no analogue in the natural world. In the current project this concept is being pursued by using ABC triblock copolymers as structure directing agents for nanoparticles of aluminosilica sols (see top Figure on the right). For the resulting hybrids a ABCD woodpile lattice has been observed that is schematically shown in the bottom figures to the right. To the best of our knowledge such a structure has not been observed before for a self-assembly system which is quite exciting and motivates further in-depth studies. Molecular structure of the ABC triblock copolymer and aluminosilica precursors. G.E.S. Toombes, S. Mahajan, M. Weyland, A. Jain, P. Du, M. Kamperman, S.M. Gruner, D.A. Muller, U. Wiesner, Self-assembly of four-layer woodpile structure from zig-zag ABC copolymer/aluminosilica concertinas, Macromolecules (2007), revised manuscript stage. Stick and space-filling model of the ABCD woodpile lattice structure found for the ABC triblock copolymer- aluminosilica hybrid.

2. ABC Block Copolymer-Nanoparticle Co-Assemblies Ulrich Wiesner, Cornell University, DMR 0605856 Education Graduate students Marleen Kamperman, and Scott Warren as well as undergraduate student Billy Yau, are involved in the research supported by this grant. This workshop was designed to give science journalists hands-on lab experience led by grad students, in addition to lectures, panel discussions and a tour of the Cornell NanoScale Science and Technology Facility. Outreach The Wiesner group is active in multiple outreach activities under the umbrella of the Cornell Center for Materials Research (CCMR). One highlight during the past year was the participation in the Kavli Institute Journalist’s Workshop on Nanotechnology in May 2007 (see Figure below). 2007 Social gathering for female engineering grad students. Another example is the organization of a social gathering for all female grad students in the College of Engineering of Cornell University in July 2007, initiated by Wiesner group grad student Marleen Kamperman together with grad student Lydia Contreras (see Figure above). Grad student Marleen Kamperman participating in CCMR’s 2007 Kavli Institute workshop for science journalists.