Composition and polymer

Abstract

The objective of this invention is to provide a composition and polymer that exhibit good substrate selectivity and can form a polymer brush with good brush density and heat resistance. The solution of this invention is a composition used for selectively modifying a substrate having a surface comprising two or more regions with different materials, comprising a polymer (A) and a solvent (S), wherein the polymer (A) has constituent units derived from styrene and / or constituent units derived from styrene derivatives, and the polymer (A) has a group represented by the following formula (1) at the end of its main chain.