We report the phase behavior of a new class of polymer

nanocomposites, montmorillonite (MMT) block copolymer brushes

(MBBs). MBBs are comprised of discrete MMT particles encapsulated with block copolymer brushes synthesized via surface initiated atom transfer radical polymerization. Polystyrene-b-poly(n-butyl acrylate) MBBs of varying composition and total Mn = 80--250 kDa were compared with bulk block copolymers via electron

microscopy and a host of mechanical tests. MBBs were found to self

assemble into single grain morphologies across incredibly large

areas (> 3 um). Perhaps most promising is that MBBs maintain

similar melt state properties to bulk block copolymers and are thus

amenable to current processing techniques.