Guided self-assembly of block-copolymer nanostructures

Abstract

Block copolymers are an important class of soft-materials with significant potential for a variety of potential applications ranging from high-density data storage devices to nanowires and photonics. These potential applications rely on the ability to not only manipulate and control their structure at the nanoscale, but also to accurately measure the structure and morphology of the film in all dimensions. As is well known, diblock copolymer molecules are comprised of two dissimilar polymers covalently bonded at one end. Typically, the individual blocks are thermodynamically incompatible and the system will microphase separate upon heating. It is also desirable to control order, orientation and defects over large areas in most thin film applications of these materials.1-5 This paper focuses on the dynamics of directed self-assembly of block copolymers in confining geometries such as thin films modulated by processing parameters such as applied fields which can be surface chemical or thermal gradient. We illustrate the surface chemical gradient approach below. The presentation will discuss some of the " tomographic" neutron scattering measurement methods being developed to investigate the structure and morphology of block copolymer thin films in 3-dimensions as a result of such gradient fields and simulation methods to capture aspects of kinetics and dynamics involved in the evolution of thin film structure.