(603a) Inorganic and Organic Nanoparticle Arrays Templated in Thermoreversible Block Copolymer Hydrogels

Block copolymers form highly organized structures when they are dissolved in solvents that are selective between the different polymer blocks. We have developed a general method to template nanoparticle arrays using thermoreversible copolymer cubic crystals. Shear orientation of block copolymer cubic crystals into macroscopic single crystals has been previously demonstrated. We show that this shear orientation is also possible for block copolymer nanocomposites containing nanosized additives (inorganic nanoparticles or proteins) intercalated in the interstitial cavities of the micelle crystal. The shear-aligned nanocomposite is a single crystal macro-domain where the templated particles have the same lattice orientation. Using small angle neutron scattering (SANS) under shear, we show that alignment is possible in mesophases of FCC micelle crystals and in close-packed arrays of cylindrical micelles. We characterize the effect of shear rate, relative size of nanoparticle and polymer template, relative concentrations, and temperature on the final state of alignment of the nanocomposite. This technique represents a simple but significant improvement in our ability to manipulate materials at the nanometer scale.