Nanorods in functionalized block-copolymer gels: Flexible ladders and liquid crystalline order in curved geometries

Department of Physics and Astronomy and Ames Laboratory, Iowa State University - Ames, IA, USA

Received: 16 July 2012
Accepted: 14 November 2012

Abstract

Polymer nanocomposites (PNCs) hold great promise for designing novel materials. Current challenges in PNCs are achieving nanosized dispersion of the inorganic component as well as robust control of nanoparticle orientation. We show that a gel of multi-block polymers with functionalized end groups that have specific affinity towards nanorods provides a general example of a PNC where the inorganic component is dispersed at the nanometer scale and displays long range as well as orientation order. We find a novel type of liquid crystalline (LC) order consisting of thin nanorod strips, i.e., “flexible ladders” (FL). Depending on concentration and affinity, FL display positional long-range order and patch together into 2D smectic phases. We discuss implications for designing new PNCs and address possible realizations of our systems via DNA linkers. The problem of LC order on curved geometries is also discussed.