FRACTAL HOLE GROWTH IN STRAINED BLOCK-COPOLYMER FILMS

The evolution of surface topography in conformationally strained diblo ck copolymer films comprised of 3/2 lamellar bilayers was investigated by optical microscopy. Films of thickness 1.25D < L < 1.5D developed two-dimensional isotropic fractal holes with d(f) = 1.67 following het erogeneous nucleation, where D is the equilibrium lamellar spacing. A microscopic theory is presented that maps this hydrostatic tension dri ven hole growth instability onto the classical description of pattern formation during solidification.