Theoretical study of block copolymer self-assembly

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Polymers are long, chain-like molecules that can occur naturally (e.g., DNA) or can be produced in the lab via synthetic techniques (e.g., polystyrene). The rubber and plastics in our everyday lives are made of polymers. Block copolymers are produced by specialized synthetic techniques that chemically bond the end of one polymer species, or block (e.g., polystyrene) to a different polymer species (e.g., polyisoprene). The tendency for unlike blocks to repel would lead the system to separate into macroscopic domains of each species, if it weren't for the chemical bond between the blocks. The best the block copolymer can do is to separate its blocks into domain structures on a scale set by the size of the polymer, that is, tens of nanometers. The ability to spontaneously organize (self-assemble) into these microstructures make these materials potentially useful in applications requiring such resolution. For example, there is an ongoing, world-wide effort to investigate the use of block copolymers as structural templates for lithography, and for the production of ordered arrays of metallic nano-dots and nano-wires. These templates hold the promise of shrinking microelectronic circuits to the 10 nm scale, below that accessible to traditional photolithography. One aspect of my research centres on understanding how confinement of a block copolymer into a cylindrical nanopore influences the self-assembly process and creates new microstructures. This may lead to potentially novel applications. When processing these materials it is also important to have a fundamental understanding of the time it takes the system to form these structures, that is, the kinetics of self-assembly. This is another research focus of my group. Key questions are: What is the relation between microstructure and dynamics? What are the kinetic pathways for, and barriers to, the formation of a given structure? How do we formulate a non-equilibrium theory to answer these questions? My group tackles these problems using a combination of sophisticated analytical methods and high-performance computing. This work is expected to result in major advances in our understanding of the dynamics of block copolymers, and will enhance Canada's overall research effort in novel, soft-materials.