Thermoplastic polymer comprising a thermoplastic polymer block and at least one polyalkylene oxide block, characterized in that: a) the thermoplastic polymer block comprises: • a star- or H-configured macromolecular chain comprising at least one multifunctional core and at least one thermoplastic polymer branch or segment linked to the core, the core comprising at least three identical reactive functional groups; and/or • a linear macromolecular chain, comprising a difunctional core and at least one thermoplastic polymer segment linked to the core; b) the polyalkylene oxide block or blocks are linked to at least some of the free ends of the thermoplastic polymer block in the following manner: • at least one free end of the star- or H-configured macromolecular chain, chosen from among the ends of the thermoplastic polymer branch or segment and the ends of the multifunctional core, is linked to a polyalkylene oxide block; and/or • at least one free end of the linear macromolecular chain, chosen from among the ends of the thermoplastic polymer segment and the ends of the difunctional core, is linked to a polyalkylene oxide block; both free ends of the linear macromolecular chain being linked to polyalkylene oxide blocks when the thermoplastic polymer block comprises only linear-type macromolecular chains; and when the thermoplastic polymer block comprises only linear-type macromolecular chains, then the thermoplastic polymer of which both free ends of the macromolecular linear chain are linked to polyalkylene oxide blocks is obtained when the following are reacted: - on the one hand, polyalkylene oxide blocks possessing a single reactive terminal functional group B, - on the other hand: - thermoplastic polymer macromolecular chains possessing at least reactive terminal functional groups A, and/or - compounds of at least two types: ⇒ difunctional compounds comprising reactive functional groups A, ⇒ monomers each comprising reactive functional groups A and B and/or a thermoplastic polymer comprising reactive functional groups A and B, the functional groups A and B possibly reacting together to fix the polyalkylene oxide blocks to the thermoplastic polymer macromolecular chains and/or the monomers and/or the thermoplastic polymer; the above being heated to a temperature high enough to carry out the reaction between these various functional groups. a) the thermoplastic polymer block comprises: • a star- or H-configured macromolecular chain comprising at least one multifunctional core and at least one thermoplastic polymer branch or segment linked to the core, the core comprising at least three identical reactive functional groups; and/or • a linear macromolecular chain, comprising a difunctional core and at least one thermoplastic polymer segment linked to the core; • a star- or H-configured macromolecular chain comprising at least one multifunctional core and at least one thermoplastic polymer branch or segment linked to the core, the core comprising at least three identical reactive functional groups; and/or • a linear macromolecular chain, comprising a difunctional core and at least one thermoplastic polymer segment linked to the core; b) the polyalkylene oxide block or blocks are linked to at least some of the free ends of the thermoplastic polymer block in the following manner: • at least one free end of the star- or H-configured macromolecular chain, chosen from among the ends of the thermoplastic polymer branch or segment and the ends of the multifunctional core, is linked to a polyalkylene oxide block; and/or • at least one free end of the linear macromolecular chain, chosen from among the ends of the thermoplastic polymer segment and the ends of the difunctional core, is linked to a polyalkylene oxide block; • at least one free end of the star- or H-configured macromolecular chain, chosen from among the ends of the thermoplastic polymer branch or segment and the ends of the multifunctional core, is linked to a polyalkylene oxide block; and/or • at least one free end of the linear macromolecular chain, chosen from among the ends of the thermoplastic polymer segment and the ends of the difunctional core, is linked to a polyalkylene oxide block; - on the one hand, polyalkylene oxide blocks possessing a single reactive terminal functional group B, - on the other hand: - thermoplastic polymer macromolecular chains possessing at least reactive terminal functional groups A, and/or - compounds of at least two types: ⇒ difunctional compounds comprising reactive functional groups A, ⇒ monomers each comprising reactive functional groups A and B and/or a thermoplastic polymer comprising reactive functional groups A and B, ⇒ difunctional compounds comprising reactive functional groups A, ⇒ monomers each comprising reactive functional groups A and B and/or a thermoplastic polymer comprising reactive functional groups A and B,