Abstract: Disclosed is a triblock copolymer including two terminal blocks derived from a block copolymer and a middle block incorporated between the terminal blocks. The middle block has a higher surface energy than the terminal blocks. Also disclosed is a method for preparing the triblock copolymer. The preparation method provides a generalized approach that is highly applicable to processes for the mass production of block copolymers and can be applied to various combinations of block copolymers as well as to specific combinations of copolymers. Also disclosed is a method for nanopatterning using the triblock copolymer. The nanopatterning method enables the formation of nanopatterns with sub-10 nm feature size with simple process and reduced cost. Therefore, the nanopatterning method can be widely used in various industrial fields such as semiconductor lithography and memory devices.