(123d) Field and Confinement-Directed Self-Assembly of Soft Mesophases to Create Useful Materials

Osuji, C. O. - Presenter, Yale University
Self-assembly of block copolymers and small molecule mesogens gives rise to a rich phase behavior as a function of temperature, composition, and other relevant parameters. The ability to precisely control their chemical functionality combined with the tunable characteristic length scales (~1-100 nm) of their self-assembled mesophases position these systems as a versatile and attractive class of materials for compelling applications ranging from membranes for size and chemo-selective transport, to lithography. As a result there is intense interest in elucidating the physical processes relevant for directing self-assembly in these materials, with a goal of exploiting such fundamental understanding in scalable processes to create useful materials or devices. This presentation highlights recent advances in scalable directed self-assembly of soft nanostructured materials and emerging methods for generating highly ordered and heterostructured systems. In particular, we focus on the use of magnetic fields and physical confinement as scalable routes for creating useful nanostructured materials from block copolymers and polymerizable small molecule mesophases. A variety of new developments are discussed including alignment using low intensity magnetic fields, the use of orthogonal stimuli to create biaxial order, and the generation of alignment patterns by field screening using magnetic nanoparticles. Emerging applications in aligned nanofiltration membranes and sub-10 nm patterning are presented.