Poly(ethylene glycol)-b-poly(halomethylstyrene), derivative thereof, and method for producing same

A block copolymer of the following formula (W):

• wherein,
• W denotes the formula
• or a hydrogen atom or a mercapto group,
• A denotes an unsubstituted or substituted C1-C12 alkoxy group, with the substituent group being a formyl group or a group represented by the formula R1R2CH— in cases where A is substituted, R1 and R2 each independently denote a C1-C4 alkoxy group or R1 and R2 together denote a —OCH2CH2O— group, a —O(CH2)3O— group or a —O(CH2)4O— group, or in cases where A is substituted, the substituent group is a group represented by the formula R3R4B-Ph-, where R3 and R4 each denote a hydroxy group or R3 and R4 together denote a —OC(CH3)2C(CH3)2O— group, and Ph denotes an o-phenylene group, m-phenylene group or p-phenylene group that may be substituted by a methyl group or methoxy group,
• L is m-xylylene or p-xylylene,
• R groups each independently denote a methyl group or methoxy group, a is an integer between 0 and 3,
• m is an integer between 3 and 500,
• n is an integer between 2 and 10,000,
• Z is selected from groups represented by the formulae below, which are covalently bonded via a —NH— group or —O— group:
• or denotes a —P(═O)(OCH2CH3)2 group or —P(═O)(OH)2 group,
• with these groups accounting for at least 60% of the total number of Z groups, and the remaining Z groups, when present, being chlorine atoms, bromine atoms, iodine atoms or hydroxyl groups.