Abstract: The invention relates to a block copolymer film nanostructured in nanodomains, said copolymer comprising at least one first biodegradable block and a second block of a different chemical nature than the first block, said block copolymer being characterized in that the first biodegradable block is amorphous and in that the second block is derived from an oligomer or a polymer bearing a hydroxyl function on at least one end and acting as macro-initiator of the polymerization of the first block.

Abstract: Provided is a block copolymer film nanostructured in nanodomains, where the copolymer includes at least one first biodegradable block of polyester type and a second block of a different chemical nature than the first block. The first block of polyester type is polybutyrolactone (PBL) and the second block is derived from an oligomer or from a polymer bearing a hydroxyl function on at least one end and acting as macro-initiator of the polymerization of ?-butyrolactone (?-BL) to give polybutyrolactone (PBL).

Abstract: The invention relates to a process for controlling the structure of a block copolymer by selective copolymerization, by ring opening, of cyclic carbonate and lactone monomers in the presence of a catalyst based on methanesulfonic acid, the said process comprising a sequence of stages carried out strictly in the following order: a) dissolving the cyclic carbonate monomer in a nonchlorinated aromatic solvent, b) adding, to the monomer solution, a bifunctional initiator chosen from diols or water, c) adding methanesulfonic acid (MSA) as catalyst of the polymerization reaction, d) when all the cyclic carbonate has been consumed, a telechelic polycarbonate capable of acting as macroinitiator of polymerization of the lactone is obtained, e) adding the lactone to the reaction medium in order to selectively obtain a block copolymer.