The invention relates to a crosslinkable prepolymer composition for use as a contrast layer. It also relates to a method for structuring an interface material. This method is characterized in particular by the following steps:
depositing, on a block copolymer film, a prepolymer composition layer comprising a plurality of functional monomers and at least one crosslinkable functional group within its polymer chain and, on the other hand, two chemically different crosslinking agents, each agent being capable of initiating the crosslinking of said prepolymer in response to a stimulation specific thereto,
subjecting the stack to a first stimulation localized on first areas, so as to cause a crosslinking reaction of the molecular chains of said prepolymer, and subjecting the stack to a second stimulation, so as to cause crosslinking of the molecular chains of said prepolymer by the action of said second crosslinking agent in secondary areas.