A method of surface treating a fluid dispenser device, characterized in that said method comprises a step of modifying, by ionic implantation, by means of multi-charged and multi-energy ion beams, at least one surface to be treated of at least a portion of said device in contact with said fluid, said modified surface having properties limiting the appearance and/or proliferation of bacteria on said modified surface, said multi-charged ions being selected from helium (He), boron, carbon, nitrogen, oxygen, neon (Ne), argon (Ar), krypton (Kr), and xenon (Xe),ionic implantation being carried out to a depth of 0 μm to 3 μm, said method comprising a method of deep layer grafting monomers into an organic material, comprising two steps in succession: a) a step of ionic bombardment by an ion beam to create: - a reservoir of free radicals in a layer with a thickness e rad in the range 20 nm to 3000 nm; and - a stabilizing layer interposed between the surface and the reservoir of free radicals with a thickness e stab in the range 0 nm to 3000 nm; - the ions of the ion beam are selected from the ions of elements in the list constituted by helium (He), boron, carbon, nitrogen, oxygen, neon (Ne), argon (Ar), krypton (Kr), and xenon (Xe); - the ion acceleration voltage is greater than or equal to 10 kV and less than or equal to 1000 kV; and - the treatment temperature of the organic material is less than or equal to its melting temperature; - the ion dose per unit area is selected so as to be in the range 10 12 ions/cm 2 to 10 18 ions/cm 2 by using a measurement of the change over time of the surface resistivity of the organic material to identify the dose that induces the greatest resistive jump step; b) a step of grafting monomers, consisting of diffusing monomers through a stabilizing layer from the surface towards the reservoir of free radicals at a diffusion temperature T d, the diffusion temperature T d being in the range from ambient temperature to the melting temperature T f of the organic material. a) a step of ionic bombardment by an ion beam to create: - a reservoir of free radicals in a layer with a thickness e rad in the range 20 nm to 3000 nm; and - a stabilizing layer interposed between the surface and the reservoir of free radicals with a thickness e stab in the range 0 nm to 3000 nm; - the ions of the ion beam are selected from the ions of elements in the list constituted by helium (He), boron, carbon, nitrogen, oxygen, neon (Ne), argon (Ar), krypton (Kr), and xenon (Xe); - the ion acceleration voltage is greater than or equal to 10 kV and less than or equal to 1000 kV; and - the treatment temperature of the organic material is less than or equal to its melting temperature; - the ion dose per unit area is selected so as to be in the range 10 12 ions/cm 2 to 10 18 ions/cm 2 by using a measurement of the change over time of the surface resistivity of the organic material to identify the dose that induces the greatest resistive jump step; - a reservoir of free radicals in a layer with a thickness e rad in the range 20 nm to 3000 nm; and - a stabilizing layer interposed between the surface and the reservoir of free radicals with a thickness e stab in the range 0 nm to 3000 nm; - the ions of the ion beam are selected from the ions of elements in the list constituted by helium (He), boron, carbon, nitrogen, oxygen, neon (Ne), argon (Ar), krypton (Kr), and xenon (Xe); - the ion acceleration voltage is greater than or equal to 10 kV and less than or equal to 1000 kV; and - the treatment temperature of the organic material is less than or equal to its melting temperature; - the ion dose per unit area is selected so as to be in the range 10 12 ions/cm 2 to 10 18 ions/cm 2 by using a measurement of the change over time of the surface resistivity of the organic material to identify the dose that induces the greatest resistive jump step; b) a step of grafting monomers, consisting of diffusing monomers through a stabilizing layer from the surface towards the reservoir of free radicals at a diffusion temperature T d, the diffusion temperature T d being in the range from ambient temperature to the melting temperature T f of the organic material.