BASE MATERIAL AND METHOD FOR PRODUCING STRUCTURE INCLUDING PHASE-SEPARATED STRUCTURE

原文（中国語）

A base material capable of forming a phase-separated structure excellent in horizontal orientation. The base material contains a block copolymer including a block (A1) having a constituent unit represented by the following Formula (a1) and a block (A2) having a constituent unit represented by the following Formula (a2), and a molar ratio of the constituent unit of the block (A2) of more than 0 mol % and 40 mol % or less. In Formula (a1), Rrepresents a hydrogen atom, Rrepresents a substituent, and n is an integer of 0 to 5; and in Formula (a2), Rrepresents a hydrogen atom, Lrepresents a single bond, and Yrepresents a divalent linking group having 1 to 15 carbon atoms