Patent ID: 7739789

Claim:
A method for forming a surface graft, comprising the process of applying energy to the surface of a substrate containing polyimide represented by general formula (IV): wherein R 1 represents a tetravalent organic group, R 2 represents a divalent organic group, n represents an integer of 1 or more, and at least one of R 1 and R 2 is a group containing a structure having a polymerization initiating ability, wherein the structure having a polymerization initiating ability is selected from the group consisting of an aromatic ketone, an onium salt compound, an organic peroxide, a thio compound, a hexaaryl biimidazole compound, a ketoxime ester compound, a borate compound, an adinium compound, an active ester compound, a compound having a carbon halogen bond, and a pyridinium compound, to generate active points on the surface of the substrate and to generate a graft polymer that is directly bonded to the surface of the substrate starting from the active points and that has a polar group.