Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
  • B05D3/06—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by exposure to radiation
  • B05D3/068—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by exposure to radiation using ionising radiations (gamma, X, electrons)
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
  • C08J7/12—Chemical modification
  • C08J7/123—Treatment by wave energy or particle radiation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B15/00—Layered products comprising a layer of metal
  • B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
  • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
  • C23C14/48—Ion implantation
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/27—Web or sheet containing structurally defined element or component, the element or component having a specified weight per unit area [e.g., gms/sq cm, lbs/sq ft, etc.]
  • Y10T428/273—Web or sheet containing structurally defined element or component, the element or component having a specified weight per unit area [e.g., gms/sq cm, lbs/sq ft, etc.] of coating

Definitions

• the subject of the invention is a process for grafting monomers in a deep layer in an organic material by an ion beam.
• the invention aims in particular to create thick water-repellent barriers, to greatly improve the adhesion of water-based varnishes on elastomers, to constitute antibacterial barriers characterized by long-lasting effectiveness.
• the invention finds applications in the field of pharmaceutical packaging where it is sought, for example, to prevent the diffusion of ambient moisture through flasks in order to prevent the degradation of the active principles contained therein.
• the invention also has applications in all industries using, for example, aqueous-based varnishes applied to elastomers or on the one hand seeks to improve the mechanical compatibility (varnish / elastomer) by reinforcing the hardness of the latter, d.
• Another application is to treat the PEEK sheath of electric cables used in the oil industry to enhance their resistance to oxidation under extreme humidity and temperature conditions.
• organic means a material consisting of carbon atoms bonded to one another or to other atoms by covalent bonds. This category includes materials belonging for example to the family of polymers, elastomers or resins. These organic materials have the specificity of being generally electrical insulators and subject to the production of free radicals under the effect of ionizing radiation among which are counted UV rays, X, ⁇ , the electron beams, the beams of ions.
• monomer is meant a single molecule used for the synthesis of polymers.
• these monomers must have unsaturations (for example a double bond) capable of reacting with the free radicals generated in the organic material by the ionizing radiation.
• ionizing radiation of the electron bombardment or gamma-ray type creates free radicals (ionization reaction) which can either recombine with each other by so-called crosslinking reactions by creating new covalent bonds between atoms. organic material, or to allow the grafting of monomers from the outside with atoms of the organic material.
• the free radicals react with monomers having a vinyl or acrylic functional unsaturation.
• Ionizing radiation by electron bombardment or gamma radiation and associated irradiation facilities allow the grafting of media in very different forms: films, textile surfaces, compound granules, medical devices for example.
• a monomer carrying a graftable unsaturation of vinyl, allylic or acrylic type may be attached to a carbon chain under the effect of ionizing radiation.
• the support material According to the other chemical functions (or ligands) carried by the monomer, particular characteristics can thus be permanently conferred on the support material: antiseptic properties, ionic exchangers, adhesion promoters, etc.
• the grafting methods by electron bombardment or gamma rays have disadvantages related to the means of production of ionizing particles and their range, which has the effect of greatly limiting their use.
• Gamma-producing facilities are extremely cumbersome to manage both technically and in terms of security. They consist of a radioactive source of cobalt-60, in the form of pencils, confined in a concrete casemate with walls 2 m thick.
• the casemate also houses a pool of source panels, intended for biological protection when the source is in the "rest" position.
• an overhead conveyor carrying containers (also known as swings), ensures the circulation of products to be treated around the source suspended in the cell, as well as the transfer of products between the inside and the outside of the casemate.
• the baffle geometry of the latter ensures the confinement of the radiation, while allowing the continuous scrolling of the products.
• the power of the source can reach several millions of curie.
• the facilities producing the electronic beams are just as heavy in their implementation. It is necessary to provide thick shielding systems to stop the intense production of X-radiation generated by the deceleration of electrons in the material.
• the electron beams can by the accumulation of electrostatic charges in the heart of an insulating organic material, cause its bursting.
• Another disadvantage this time physical is related to the power of penetration too high gamma radiation (several meters) and electrons (several mm). These penetration powers are not suitable for a treatment or one seeks to treat the surface without modifying the mass properties of the organic material. In fact, it is undesirable for an elastomer to lose its mass elasticity properties and to increase in rigidity to the point of not being able, for example, to conform to a curved surface (for example a windscreen wiper).
• Cold plasmas are ionized media obtained by the excitation of a gas (usually under a primary vacuum) under the effect of an electric discharge: radio frequency (kHz to MHz) and microwave (2.45 GHz) plasmas are the most commonly used. This gives a mixture of neutral molecules (majority) of ions (negative and positive), electrons, radical species (very active chinniquennent) and excited species. These plasmas are said to be “cold” because they are non-equilibrium thermodynamic media where the energy is mainly captured by the electrons but where the "macroscopic" temperature of the gas remains close to the ambient temperature. The electrons emitted by the electrode collide with the gas molecules and activate them.
• This type of treatment affects only the first nanometers of the plasma surface.
• the surface of a polymer thus activated can then be brought into contact with specific biocompatible molecules (heparin, phospholipids, etc.) to fix them by chemical bonds.
• specific biocompatible molecules heparin, phospholipids, etc.
• the chemical grafting is carried out by placing the material to be treated outside the zone of creation of the discharge (post-discharge). Due to the extreme weakness of grafted thicknesses the treatment has a limited effectiveness over time. It is also sensitive to the conditions of use (wear, friction, abrasion) which can lead to its disappearance very early.
• the invention aims to provide a deep layer grafting method of inexpensive organic material and to treat surfaces meeting the needs of many applications.
• the invention thus proposes a method of deep layer grafting by an ion beam of an organic material which comprises two steps: a) an ion bombardment where:
• the ions of the ion beam are selected from the ions of the elements of the list consisting of helium (He), boron (B), carbon (C), nitrogen (N), oxygen (O), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe);
• the ion acceleration voltage is greater than or equal to 10 kV and less than or equal to 1000 kV;
• the temperature of the organic material is less than or equal to the melting temperature
• the dose of ions per unit area is chosen in a range of between 10 12 ions / cm 2 and 10 18 ions / cm 2 so as to create by ion bombardment a layer constituting a reservoir of free radicals which makes it possible, during a second step the grafting of monomers.
• This reservoir of free radicals is characterized by a superficial layer of a thickness of the order of a few microns.
• This reservoir of free radicals may optionally be separated from the ambient environment by an extreme surface layer totally crosslinked by ion bombardment and consisting essentially of amorphous carbon.
• This layer of amorphous carbon at the extreme surface which is by nature less reactive, has a stabilizing effect on the free radical reservoir with respect to the ambient medium and makes it possible to increase the surface hardness of the organic material.
• the diffusion temperature must be chosen in a way: - to activate the free radicals present in the treated thicknesses (stabilizing layer + reservoir of free radicals);
• the glass transition temperature Tg seems the most appropriate. According to another embodiment, it is possible to explore intermediate temperatures between the glass transition temperature Tg and the melting temperature with precautionary cooling conditions to recover the properties of the original organic material. Finally, according to a third mode, the possibility of exploring temperatures between room temperature and the glass transition temperature is reserved if the density and the reactivity of the free radicals, the diffusion rate of the monomers are sufficiently large to reduce the times considerably. grafting. The choice of the diffusion temperature depends enormously on the nature of the organic material and the graftable monomer.
• Hydrophobic monomers 2- (perfluoro-3-methylbutyl) ethylmethacrylate 3- (perfluoro-3-methylbutyl) -2-hydroxypropyl methacrylate -
• Antibacterial monomer bromide or dimethyloctyl ammonium chloride ethylmethacrylate, phosphate ethylene glycol methacrylate - silver ion complex
• the inventors have found that the ranges chosen according to the invention of acceleration voltage and ion dose per unit area make it possible to select optimal experimental conditions where deep layer grafting is possible thanks to an ionic bombardment treating thicknesses of the order of one micron.
• the method according to the invention can be implemented "cold", especially at room temperature and that the temperature of the organic material should be less than or equal to the melting temperature during the implementation of the method. This can advantageously prevent the organic material from undergoing physicochemical or mechanical modification or free radicals recombining with one another.
• the process according to the invention has the advantage of modifying the surface characteristics of the organic material in a thickness of the order of one micron without altering the mass properties.
• the choice of the ion dose per unit area in the dose range according to the invention may result from a prior calibration step where it is bombarded with one of the ions among He, B, C, N, O, Ne , Ar, Kr, Xe, a sample consisting of the envisaged organic material.
• the bombardment of this organic material can be carried out in different areas of the material with a plurality of doses of ions, in the range according to the invention, and the temporal evolution of the surface resistivity of the treated zones is measured under ambient conditions. in order to identify, after a duration linked to the diffusion of oxygen in the organic material, a resistive jump characteristic of the very rapid oxidation of the free radical reservoir underlying the surface.
• the inventors have found that the height of the resistive jump gives an estimate of the density of free radicals present in the reservoir and that the choice of a dose for a given organic material should be on the one that induces the highest resistive jump.
• the measurement of surface resistivity of the treated zones expressed ⁇ / ⁇ is carried out according to the IEC 60093 standard.
• this resistive jump phenomenon can be explained by the diffusion of oxygen from the air towards the reservoir of free radicals, then its very rapid recombination by radical mechanisms. with the molecules present in this area.
• This oxidation process has the effect of abruptly reducing the free radical density, in other words the surface conductivity. This is reflected when the temporal evolution of the surface resistivity of the organic material is analyzed by a resistive jump in the form of a step. For a higher dose, these free radicals disappear leaving room for amorphous carbon with very stable electrical properties over time. In this case, the temporal evolution of the surface resistivity of the organic material remains constant.
• the method according to the invention is capable of identifying a resistive jump signaling the presence of this reservoir of free radicals in a deep layer.
• the height of the step gives an estimate of the density of free radicals present in this reservoir and will be chosen so as to be as high as possible.
• the process of the invention makes it possible to simultaneously harden the surface of the organic material to a thickness of less than or equal to one micron by creating a layer of Amorphous carbon in extreme surface.
• This amorphous carbon layer can be obtained by adjusting the dose of implanted ions so as to completely cross-link the organic material at the extreme surface and partially to a greater depth. The inventors have found that this effect is particularly enhanced for multicharged multi-energy ions from an ECR source.
• the method according to the invention has the advantage of creating thick water-repellent or antibacterial barriers, therefore effective over time or under severe conditions of use without modifying the mass properties of the organic material. In fact, it is possible to envisage replacing glass bottles with plastic bottles that have become, after treatment, impermeable to ambient humidity. Another example, the method according to the invention has the advantage of providing the elastomers excellent wettability properties (hydrophilic) combined with a highly compatible surface hardness for the application of a water-based varnish.
• the ion dose per unit area is between 10 13 ions / cm 2 and 5 10 17 ions / cm 2 ;
• the polymeric material belongs to the family of polymers, elastomers or resins
• the ion acceleration voltage is between 20 kV and 200 kV;
• the ions are produced by an electron cyclotron resonance (ECR) source which has the advantage of being compact and energy efficient and of producing multicharged multi-energy ions favorable to the creation of a hybrid layer (amorphous carbon layer / layer graftable).
• ECR electron cyclotron resonance
• FIG. 1 illustrates the formation of a layer consisting of an amorphous carbon layer at the extreme surface and a reservoir of free radicals located at greater depth;
• FIG. 2 illustrates the characteristic temporal evolution of the surface resistivity of a raw organic material treated by the method of the invention
• FIG. 3 illustrates experimentally the evolution of the surface resistivity for different doses of a polycarbonate treated with He + ions, He 2+ .
• the method recommended by the process of the invention makes it possible to identify a reservoir of free radicals that is particularly favorable for deep layer grafting. This identification consists of recognizing a clearly marked resistive jump;
• FIG. 4 illustrates a first embodiment of an antibacterial surface by the method of the invention
• FIG. 5 illustrates a second embodiment of an antibacterial surface by the method of the invention.
• FIG. 6 illustrates the release of bactericidal ions in a fluid deposited on an antibacterial surface treated according to the method of the invention.
• polycarbonate samples have been investigated for treatment with helium ions emitted from an ECR source.
• the sample to be treated moves with respect to the beam with a displacement speed of 40 mm / s with a lateral advancement step at each return of 1 mm. To reach the required dose the treatment is done in several passes.
• the temporal evolution of the resistivity of the surface of the polycarbonate was carried out based on the standard IEC 60093 which recommends the measurement after one minute of the electrical resistance existing between two electrodes, one consisting of a disc of diameter d, the other of a disc-centered ring and an internal radius D. These electrodes are placed on the surface of the polycarbonate and are subjected to a voltage of 100 V. D is equal to 15 mm and d is equal to 6 mm. The resistivity measurement is possible only for values lower than 10 15 ⁇ / ⁇ .
• samples of PP polypropylene
• acrylic acid for treatment with helium ions emitted by an ECR source.
• the sample to be processed moves relative to the beam with a displacement speed of 80 mm / s with a lateral advancement step at each return of about 3 mm. To reach the required dose the treatment is done in several passes.
• PP polyethylene samples were bombarded according to different doses corresponding to 2.10 14 5.10 14, 10 15 ions / cm 2.
• the behavior of the PP changes, the raw sample exhibits a rather hydrophobic behavior (contact angle of 76 °) while the treated samples exhibit a behavior that tends to be more hydrophilic (smaller contact angle of 64 °). It is observed that the hydrophilic behavior is markedly improved for doses of between 5 ⁇ 10 14 and 10 15 ions / cm 2 . It can be seen that the FTIR analysis of the PP treated with He indicates a dose of the same order of magnitude as those obtained by measuring the surface conductivity on PC treated with He.
• polypropylene samples have been subjected to grafting studies with acrylic acid for treatment with nitrogen ions emitted by an ECR source.
• the ion beam with an intensity of 300 ⁇ comprises ions N + + , N 2+ , N 3+ with respective distributions 60%, 40%, 10%; the extraction and acceleration voltage is 35 kV; the energy of N + is 35 keV, that of N 2+ is 90 keV, and that N 3+ is 105 keV.
• the PP samples were bombarded at different doses at 2.10 14 , 5.10 14 , 10 15 , 5.10 15 ions / cm 2 .
• the sample to be processed moves with respect to the beam with a speed of displacement at 80 mm / s with a lateral advancement step at each return of 3 mm.
• This layer is covered by the Acrylic acid molecules in a relatively short time both at 40 ° C or 60 ° C, before there can be a beginning of recombination of free radicals with each other, at the very heart of the reservoir created by the ion bombardment.
• the grafting of the acrylic acid with the free radicals of the tank is in this case total.
• the contact angle tends to increase along with the thickness of the stabilizing layer that separates the reservoir from free radicals from the surface.
• the temperature rather favors a recombination of the free radicals between them to the detriment of the grafting.
• Acrylic acid then no longer has time to reach the reservoir of free radicals for grafting.
• the contact angle of the drop at 60 ° C is higher than at 40 ° C.
• the inventors have been able to conclude that it is preferable in this case to graft at 40 ° C. or even at room temperature rather than at 60 ° C.
• the optimum dose for which the absorption peak (transmittance decrease) is the largest is around 10 15 ions / cm 2 . This is true for both CO (1710 cm-1) and OH (3200 cm-1) groups.
• the absorption peaks are lower at 60 ° C. than at 40 ° C., thus confirming that part of the free radicals recombine in part between them under the effect of temperature.
• N1 x Eion (E1) N2 x Eion (E2)
• N1 is the dose (the number of ions per unit area) associated with the highest resistive step of an ion (1).
• E1 the energy of the ion (1).
• Eion (E1) is the ionization energy of the ion (1) at the beginning of the path in the polymer. This energy corresponds to the energy given by the ion (1) to the electrons of the polymer in the form of ionization.
• N2 is the dose (the number of ions per unit area) associated with the highest resistive step of an ion (2).
• E2 is the ionization energy of the ion (2) at the beginning of the path in the polymer.
• This ionization energy is a function of the nature and energy of the ion and the nature of the polymer.
• the first line of the table contains the known experimental data: He ion type implemented, 35 keV energy of the ion used, 10 eV / Angstrom ionization energy ceded by helium at the beginning of the path in the PP (provided by TRIM & SRIM).
• the dose October 15 ion / cm 2 dose is identified by experiment corresponding to the resistive walking jump for the PC, knowing that the PC has an ionization energy (9.5 eV / Angstrom) almost identical to that of PP.
• the third line is another example of grafting with argon to be validated. For this one deduces a dose corresponding to the highest resistive step step which would be around 5.10 14 ion / cm 2, in other words relatively close to that obtained with the nitrogen beam.
• the treated polymer can be grafted several days after the bombardment. This is not the case for other grafting techniques by plasmas, electron beam and gamma ray. These techniques do not create a stabilizing layer, the polymers thus treated must be kept in the dark at a low temperature, below -20 ° C, before grafting.
• the principle of antibacterial grafting is as follows: the acrylate reacts with free radicals for attach to the substrate carrying with it the bactericidal metal ion loosely attached to its termi CO 2 season " . The metal ion can then be released to the outside to exert its bactericidal action.
• acrylic acid the non-binding electron pairs of the hydroxyl group of acrylic acid are indeed capable of scavenging metal ions by chelation.
• a second step or load the grafted layer with bactericidal metal ions by immersing in a solution containing these same ions. Once stored in the graft layer, these metal ions Bactericides are released as soon as they come into contact with a fluid deposited on the grafted layer. The bactericidal metal ions diffuse into the fluid and exert their bactericidal action provided that their concentration exceeds a bactericidal concentration threshold specific to the nature of the ion.
• silver ion For the silver ion (Ag + ), it is known that a concentration threshold of 20 ppm (parts per million), that is to say 20 mg per kg, is highly bactericidal to destroy bacteria such as Staphylococcus aureus (Staphylococcus aureus). methicillin or MRSA) Enterococcus faecium (Enterococcus resistant to vancomycin or ERV) Enterococcus fecalis Burkholderia cepacia Alcaligenes sp. Pseudomonas eruginosaKIebsiella pneumoniae Pseudomonas sp. Acinetobacter sp. itrobacter koseri.
• the antibacterial grafted layer acts, as a bactericidal ion exchanger whose characteristics can advantageously be adjusted for:
• the inventors have developed a model for the grafting and storage of metal ions making it possible to establish a formula that is useful for carrying out predictions on metal ion storage capacity according to the parameters of the bombardment.
• This model is based, on the one hand, on the specific nature of the grafted layer, as it could be observed experimentally (reservoir of free radicals flush with the surface and protected by a stabilizing layer of amorphous carbon), on the other hand. on the steric hindrance considerations whose effect is to limit the grafting independently of the number of free radicals present.
• the monomers constituting the polymer have an equiprobable number of free radicals which decrease from the extreme surface at the end of the course of the ion.
• the grafting of the monomers to be grafted is limited by the size of the monomers constituting the polymer.
• the monomers to be grafted are of comparable size to the monomers constituting the polymer, it is not possible to graft more than one monomer onto a monomer constituting the polymer.
• the rule of grafting is as follows: the number of monomers Ng that can be grafted onto a monomer constituting the polymer is between (Lp / Lg) and (Lp / Lg) -1 if Lp> Lg, or Lg is the length of the monomer to be grafted and Lp the length of the monomer constituting the polymer; if Lp ⁇ Lg, N G is equal to Lp / (Lg + 1).
• the grafted monomers establish weak bonds with the bactericidal metal ions.
• the number of bactericidal ions bound to a grafted monomer can be deduced by considering its chemical composition.
• a grafted monomer such as acrylic acid can accommodate by chelation only one Ag + or Cu 2+ ion which binds to one of the two non-linking doublets of the hydroxyl group (OH). From these hypotheses the inventors were able to establish the following formula:
• Nion (1/2) .6.02x10 23 .Ep. (P / M mO i) .KA or, where:
• Nion represents the number of bactericidal ions stored and released per unit area.
• • 1/2 represents a corrective factor that takes into account the linear decay of free radicals from the extreme surface at the end of the path of the ion.
• E p represents the bombarded and grafted thickness. This thickness is a function of the energy of the ion, its nature and the nature of the polymer. It is calculable with TRIM & SRIM software.
• P represents the density density of the polymer.
• K represents the average number of monomers grafted per monomer constituting the polymer.
• K (2x (Lp / Lg) -1) / 2.
• This number K can be refined, corrected or even deduced directly by experience.
• a technique called RBS Rutherford Back Scattering
• RBS Rutherford Back Scattering
• A the number of monomeric bonded metal ions grafted (storable and releasable).
• We can deduce A from the chemical composition of the grafted monomer. For example, for a silver acrylate monomer, there is only one silver ion (Ag +) per grafted acrylate monomer: A 1.
• A 1.
• Cs defined as the mass of bactericidal metal ions stored and releasable per unit area:
• Nion represents the number of bactericidal metal ions stored and released per unit area.
• N is the number of atoms per unit volume of metal from which the bactericidal metal ions are made
• K 0.5;
• the surface charge of Ag + ions stored and releasable by a layer bombarded with He, grafted with acrylic acid and then immersed in an Ag + ion solution has highly bactericidal characteristics for treating a volume of fluid. about 1, 9 cm 3 (the threshold bactericidal concentration of Ag + is 20 ppm, ie 20 g / cm 3 ).
• the surface charge of stored and releasable Ag + ions is lower but still remains as effective at treating 0.65 cm 3 .
• the surface charge of stored and releasable Ag + ions allows effective treatment of a 2 mm thick fluid film. It is thus possible to modulate the bactericidal properties of a surface treated according to the method of the invention as a function of the intended applications, be it a drop of fluid, a film of fluid, etc.
• the charge of Cu2 + ions stored and released by a layer bombarded with He, grafted with acrylic acid and then immersed in a solution of Cu2 + ions has highly bactericidal characteristics for treat a volume of fluid of approximately 2.1 cm 3 (the bactericidal concentration threshold of Cu 2+ is 10 ppm, in other words equal to 10 ⁇ g / cm 3 ).
• Another approach is for a given type of ion, to adjust the energy of the ion, in other words to adjust the depth of the treatment thickness Ep, to store and release a charge of bactericidal metal ions sufficient to exceed the bactericidal concentration threshold (Specific to bactericidal metal ions) in a fluid of given volume and contact area.
• the charge of releasable metal ions in the fluid is proportional to the contact area of the fluid with the bactericidal surface.
• the method of the invention makes it possible to determine the ionic bombardment parameters in order to create a grafted layer that has optimal characteristics (hydrophilic, hydrophobic, antibacterial, metal ion exchanger), while leaving open the multiple conditions of implementation: nature, temperature and concentration of monomer solutions to be grafted, of metal ions to be loaded into the grafted layer.
• These conditions of implementation act only on the chemical kinetics (speed to obtain the result). These conditions have little effect effect or not at all on the result itself.
• These implementation conditions are left to the discretion of the manufacturer, who must adjust them during preliminary tests to respond to a rate of production, economic costs, etc.
• the inventors recommend preliminary tests with solutions that do not exceed 40 ° C to avoid recombination of free radicals before grafting and concentrations of less than 10% by volume to allow good homogeneity of the solution during grafting. or during bactericidal ion loading.
• the action spectra of Ag + and Cu 2+ ions on bacterial or fungal agents partially overlap, the former being more effective, if at all, than the latter for treating a bacterium or a fungus.
• the action spectra of these ions can be broadened by immersing, for example, a bombarded and grafted PP with acrylic acid, in Cu 2+ bactericidal metal ion solutions and / or Ag + simultaneously or sequentially in one direction or the other, for the purpose of ultimately obtaining proportions of specific bactericidal metal ions stored, for example a storage bactericidal metal ions consisting of 70% silver ions (Ag + ) and 30% copper ions (Cu 2+ ).
• FIG. 1 represents the structure of a thickness of organic material produced by ion bombardment according to the method of the invention.
• an ion (X) penetrates the organic material in a thickness e pen , it produces in its path free radicals. Beyond in the layer (3), the organic material retains its original properties. Free radicals end surface recombine rapidly with each other in a zone (2) to create and preferably by crosslinking a stable layer consisting essentially of amorphous carbon in a thickness e s the tab- located more towards free radicals are more layer reactive (1) of thickness e ra d, suitable for grafting (1) This layer (1) is referred to as a free radical reservoir (r). These free radicals are available to participate in the subsequent grafting of monomers (M).
• zone (2) may not exist if the energy dose given by the Incident ions at the extreme surface are not sufficient to cause total crosslinking at the extreme surface.
• the stable layer (2) does not exist;
• the layer of organic material accessible to the incident ions (X) in a thickness merges with the free radical reservoir (1), in other words e pe n is equal to e ra d.
• the free radical reservoir (1) is in direct contact with the outside.
• the grafting performed in a second step consists of diffusing a monomer (M) from the surface of the organic material to the reservoir of free radicals (1) through a stabilized layer of amorphous carbon (2) which can be as to see it do not exist.
• the monomer (M) reacts with (r) to give a chemical grafting compound (g) having the hydrophilic, water-repellent or antibacterial properties of the original monomer.
• the thickness e ra d is between 20 nm and 3000 nm corresponding to the minimum and maximum path of the incident ions given their energy.
• FIG. 2 represents the temporal evolutions of the surface resistivity in ambient medium:
• the abscissa axis (T) represents the time and the ordinate axis (R) the surface resistivity expressed in ⁇ / ⁇ .
• 3 shows the experimental evolution of the surface resistivity of a polycarbonate versus time for various doses of helium equal to 10 15 (curve 1), 2.5.10 15 (curve 2), 5.10 15 ions / cm 2 (curve 3), 2.5 ⁇ 10 16 ions / cm 2 (curve 4).
• the resistivity measurement was carried out according to IEC 60093.
• the method for measuring surface resistivity does not measure resistivities greater than 10 15 ⁇ / ⁇ . This is represented by the area N on the graph above 10 15 ⁇ / ⁇ .
• the abscissa axis represents the time, expressed in days, separating the treatment of the sample to the extent of its surface resistivity.
• the y-axis represents the measurement of the surface resistivity expressed in ⁇ / ⁇ .
• This resistive jump reveals the existence of a reservoir of free radicals in deep layer that recombine very quickly with the oxygen of the air. Without wishing to be bound by any scientific theory, this 30-day period must represent the diffusion time of the ambient oxygen through a layer of relatively amorphous carbons located at the extreme surface and interposed between the ambient and the environment. reservoir of free radicals.
• the surface resistivity remains constant over more than 120 days around values equal to 10 11 ⁇ / ⁇ to 5.10 9 ⁇ / ⁇ and 1, 5 10 8 ⁇ / ⁇ .
• the layers obtained with doses greater than 2.5 ⁇ 10 15 ions / cm 2 are stable extremes, that it comprises very few free radicals. These layers are the result of total crosslinking resulting in the formation of a layer of amorphous carbons.
• the surface resistivity measurement is an effective method for identifying the dose, in this case 10 15 ions / cm 2 , allows grafting optimal monomers in deep layer.
• the method of the invention generally recommends identifying the dose for which the resistive jump is the highest. To accelerate this identification process, the temperature of the samples can be increased so as to increase the diffusion rate of the ambient oxygen.
• FIG. 4 shows an embodiment for creating an antibacterial layer consisting of bombarding the polymer with ions (X) to create a free radical reservoir (1) where the monomer (M) is grafted by immersion in a single monomer solution (M).
• the monomer (M) comprises a graftable portion (G x " ) and a bactericidal metal ion (m x + ) weakly bound to (G x" ).
• the stored bactericidal metal ion (m x + ) can be released in a step (a) through the stabilizing layer (2) to exert its bactericidal action.
• FIG. 5 shows a second embodiment for creating an antibacterial layer comprising a first step where the polymer is bombarded with ions (X) to create a reservoir of free radicals (1) or the grafting of the monomer (M) is carried out by immersion in a solution containing these monomers (M), then a second step where the graft polymer is immersed in a solution of bactericidal metal ions (m x + ) which diffuse in a sub-step (a) through the stabilizing layer ( 2) to be stored and fixed weakly (chelation) to the monomers (M) of the layer (1) to be able to diffuse again in a sub-step (b) through the stabilizing layer (2) to exert their bactericidal action.
• grafting in an acrylic acid solution and storage of Cu 2+ ions from immersion in a solution of copper sulphate can be used.
• FIG. 6 represents the release of bactericidal metal ions (m ⁇ + ) stored in the grafted layer (1), to the fluid deposited in the form of a drop (4) on the surface of the layer (2).
• the antibacterial effect is effective when the amount of metal ions diffused in the fluid exceeds a bactericidal concentration threshold that is estimated at 20 ppm (20 ⁇ g / cm 3 ) for Ag + ions at 10 ppm (10 Mg / cm 3 ) for copper ions (Cu 2+ ).
• V contact surface
• S the more the surface is hydrophilic, the more the contact surface is spread, the faster is the diffusion of the bactericidal metal ions in the fluid.
• the maximum bactericidal metal ion concentration that diffuses into the fluid volume is equal to (CsxS / V) where Cs is the surface charge in bactericidal metal ions of the antibacterial surface. It is impossible, given the grafting depths obtained for acceleration voltages of 1000 kV to store more than 1000 g / cm 2 .
• the organic material is mobile with respect to the ion beam at a speed, V D , of between 0.1 mm / s and 1000 mm / s. It is thus possible to move the sample to treat areas whose size is greater than that of the beam.
• the scrolling speed V D can be constant or variable.
• the organic material moves and the ion beam is fixed.
• the ion beam scans the organic material. It is also possible that the organic material moves when the ion beam is mobile.
• the same zone of the organic material is moved under the ion beam in a plurality, N, of passages at the speed V D.
• the treatment step may be static and result from one or more "flash" of ions;
• the organic material is returned to the open air before being immersed in a liquid or a gaseous atmosphere containing the monomers to be grafted in a deep layer.
• the time between ion beam treatment and immersion should be as short as possible to avoid recombination with ambient oxygen and humidity.

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• 2010
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• 2011
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  • 2011-07-01 CN CN201180035146.4A patent/CN103003340B/zh active Active
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