The mixed Langmuir monolayers and Langmuir-Blodgett (LB) films of horno-polystyrene (h-PS) and the diblock copolymer polystyrene-block-poly(2 -vinylpyridine) (PS-b-P2VP) have been characterized by the Langmuir monolayer technique and tapping mode atomic force microscony (AFM) resnectivelv. When the content of Y h-PS is below 80 wt.-%, the mixed LB films of h-PS/PS-b-P2VP mainly exhibit isolated circular nanoaggregates. With a further increase of the h-PS content (80-95%), however, highly uniform and stable necklace -network structures are observed in the mixed LB films.