CPM Seminar

Self assembly of nanophases:
stability, nonlinear dynamics, and defect control

Zhi-Feng Huang

MIAM & Department of Physics
McGill University

A great deal of interest in soft matter and its applications as advanced materials arises from the phenomenon of self-assembly. Despite its potential, spontaneous self-assembly usually leads to defected structures, fact that limits their applicability. Therefore one of the major challenges for widespread applications of these nanostructed materials is precise microstructural control, often to achieve long range order. We first discuss research on block copolymers, including the stability of ordered phases of different symmetries, and the dynamics of topological defects. We then consider the effects of external shears in promoting long range order, and address the mechanisms behind orientation selection under shear. We also discuss heteroepitaxial, strained solid films, including the assembly of nanostructures (quantum dots or quantum wires) through the development of a continuous, defectless instability, as well as the interplay between elasticity, kinetic deposition, and thermodynamics in the growth of both alloy films and multilayers. Finally, the whole physics picture and future plans for our understanding of the mechanisms underlying structure, dynamics, and response of nanoscale phases, as well as the extension to the realm of biological materials, will be briefly discussed.