Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
  • C09D5/08—Anti-corrosive paints
  • C09D5/082—Anti-corrosive paints characterised by the anti-corrosive pigment
• • 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
  • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
  • B05D7/14—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to metal, e.g. car bodies
  • B05D7/16—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to metal, e.g. car bodies using synthetic lacquers or varnishes
• • 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
  • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
  • B05D7/50—Multilayers
  • B05D7/52—Two layers
• • 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
  • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
  • B05D7/50—Multilayers
  • B05D7/56—Three layers or more
• • 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
  • Y10T428/25—Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
  • Y10T428/256—Heavy metal or aluminum or compound thereof
• • 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
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31971—Of carbohydrate

Definitions

• Nanostructured anticorrosion coating structure comprising the same, method for the corrosion protection of a substrate.
• the present invention relates to a nanostructured anticorrosive coating and a structure comprising it, which are intended to be used in aeronautical and aerospace applications, a process for the corrosion protection of a metallic or non-metallic substrate.
• protection against corrosion is generally provided by chromium-VI-based coatings deposited, for example, by anionic oxidation in a bath.
• This coating may furthermore contain additives, in particular to improve the resistance to abrasion.
• the co-adsorbed inorganic reinforcement serves only mechanical reinforcement and has no anticorrosive active role.
• US 2003/002701 1 discloses an article comprising a metal substrate and an anticorrosion coating which comprises alternating layers of organic and inorganic species, deposited by the so-called "IbI" technology. This coating further comprises a corrosion inhibiting agent or anticorrosion agent.
• the anti-corrosion agent is incorporated a posteriori in the layer, which is time-consuming and does not allow to consider the easy creation of multicompartmental and multifunctional films.
• a polyelectrolyte multilayer (s) doped with at least one anti-corrosion agent associated with a particular barrier multilayer makes it possible to improve the corrosion resistance of preferably metallic substrates.
• This multilayer doped with at least one anti-corrosion agent and delimited by this barrier multilayer constitute a main compartment.
• multilayers based on polyelectrolyte (s) are deposited according to the so-called "IbI” technology for example, by dip-coating (or dip-coating), deposition on spinning substrate (or spin-coating), spraying, spraying, laminar coating. and brush coating, and allow to obtain homogeneous films, covering and without defects, whose thickness is generally between 1 and 100 nm, but can reach several micrometers under certain deposition conditions.
• This technology makes it possible to finely control the thickness of deposited layers.
• the compounds used to obtain such films have a lower toxicity and the implementation is easy.
• These compounds have the additional advantage of being compatible with environmental regulations, and in particular of being used mainly in an aqueous medium.
• a coating comprising such a main compartment may further comprise at least one other functional agent different from an anticorrosion agent, or at least one another compartment referred to as 'secondary compartment' in which the anti-corrosion agent is replaced by another functional agent.
• the term "functional agent” is intended to mean an agent conferring a property such as corrosion resistance, mechanical strength, scratch and friction resistance, coloration, hydrophobicity, biocompatibility and / or a bactericidal character.
• the subject of the present invention is therefore a nanostructured anticorrosion coating based on polyelectrolytes, comprising at least one main compartment which comprises: a multilayer of polyelectrolyte (s) doped with at least one anti-corrosion agent, and an upper multilayer acting as a barrier to the diffusion of the doping agents, and whose upper surface corresponds to the upper surface of the main compartment.
• a multilayer of polyelectrolyte (s) doped with at least one anti-corrosion agent a multilayer of polyelectrolyte (s) doped with at least one anti-corrosion agent, and an upper multilayer acting as a barrier to the diffusion of the doping agents, and whose upper surface corresponds to the upper surface of the main compartment.
• Nanostructured coating means a coating whose structure is controlled at the nanoscale. This structure can be verified in particular by X-ray reflectometry and small-angle X-ray scattering, transmission microscopy (or TEM) or atomic force microscopy (AFM).
• the term "doping agent” is intended to mean a chemical species that is minor in relation to the polyelectrolyte (s) forming the doped multilayer.
• the doping agent makes it possible to confer a particular property on the doped multilayer.
• the doping agent (s) in the main compartment is (or is) the the anticorrosive agent (s), and optionally any functional agent other than an anti-corrosion agent as described below.
• the doping agent (s) is (or are) any functional agent other than an anti-corrosion agent as described below.
• At least one of the anticorrosive agents is in the form of nanoparticles of metal oxide or of metal salt, still more preferably of metal oxide, having, for example, a size ranging from 1 to 50 nm, better from 2 to 10 nm, as measured by TEM.
• nanoparticles examples include nanoparticles of cerium oxide, manganese oxide, cobalt oxide, phosphate oxide, zinc oxide, molybdenum oxide oxide or vanadium oxide, or rare earth salts such as Ce, Nd, Pr, La, Sm, or mixtures thereof.
• anticorrosive agents can be added by simple co-adsorption, such as organic agents such as sodium sebacate, potassium phthalate, hydroxyapatite, benzoate and sodium acetate, hydroxyquinoline, methylphenothiazine, azoles such as, for example, benzotriazole or tolylazole, or tetrachloro-p-benzoquinone (or chloranil).
• the polyelectrolyte multilayer (s) doped with at least one anti-corrosion agent comprises an anionic polyelectrolyte or a cationic polyelectrolyte, or alternating layers of anionic and cationic polyelectrolytes.
• this polyelectrolyte multilayer (s) doped with at least one anti-corrosion agent can be produced by successive deposition of a cationic (or anionic) polyelectrolyte and an anticorrosion agent in the form of negatively charged metal oxide nanoparticles ( or positively).
• Another example consists in co-depositing the anticorrosion agent together with the anionic or cationic polyelectrolytes.
• the alternative deposition of a cationic polyelectrolyte and an anionic polyelectrolyte together with nanoparticles acting as a corrosion inhibitor has the advantage of allowing the dispersion of neutral or positively or negatively charged nanoparticles.
• Such an embodiment also has the advantage of allowing crosslinking of the cationic polyelectrolyte and the anionic polyelectrolyte, in the presence of a crosslinking agent.
• a layer thus crosslinked makes it possible, among other things, to limit the mobility of the trapped nanoparticles.
• the polyelectrolyte multilayer (s) doped with at least one anti-corrosion agent comprises a cationic polyelectrolyte.
• the main compartment may further comprise a lower layer acting as a barrier to the diffusion of the doped species and whose lower surface corresponds to the lower surface of the compartment.
• the main compartment may further comprise at least one functional agent different from an anticorrosion agent.
• This or these other functional agents may be contained in the same multilayer as the anticorrosive agent or they may be contained in one or more other polyelectrolyte multilayers, or these two cases are possible in the same coating.
• a functional agent other than an anticorrosive agent, used in the coating according to the invention is an agent conferring a property on the compartment which is different from the corrosion resistance, such as, for example, a resistance to scratching and friction, a mechanical strength, a hydrophobic character, a coloration or a bactericidal effect.
• functional agents conferring resistance to scratching and friction and / or mechanical resistance to the layer mention may be made especially of titanium or aluminum alkoxides, silica or alumina nanoparticles, oxides titanium or zirconium, platelets or slips of exfoliated clay, carbon nanotubes or inorganic or ceramic nanoparticles.
• functional agents conferring a hydrophobic character there may be mentioned zirconium oxides, fluorinated polymers or copolymers.
• organic or inorganic pigments or dyes such as NiIe Blue, coumarines, fluoresceins, phthalocyanines or pyrenes.
• bactericidal agents examples include anti-bacterial peptides and metal salts such as silver salts.
• the nanostructured anticorrosion coating according to the invention may further comprise one or more secondary compartments, each comprising: a multilayer of polyelectrolyte (s) doped with at least one functional agent different from an anticorrosion agent, such as those mentioned above, and an upper multilayer acting as a barrier to the diffusion of the doping agents, and whose upper surface corresponds to the upper surface of the secondary compartment.
• a multilayer of polyelectrolyte (s) doped with at least one functional agent different from an anticorrosion agent, such as those mentioned above and an upper multilayer acting as a barrier to the diffusion of the doping agents, and whose upper surface corresponds to the upper surface of the secondary compartment.
• the multilayers that act as a diffusion barrier for the doping agents described above preferably comprise an anionic polyelectrolyte and a crosslinked cationic polyelectrolyte.
• a preferred method is to use polyacids and polyamines, and crosslink them to form amide bonds.
• barrier multilayers make it possible to limit the diffusion of the doping agents between the main and secondary functional compartments, and between the secondary compartments, practically completely or completely.
• crosslinking polyelectrolyte multilayers for example thermally, or in the presence of one or more crosslinking agents.
• the crosslinking can be carried out in the presence of a crosslinking agent chosen according to the chemical nature of the polyelectrolytes, for example, an amidation agent such as 1-ethyl-3-dimethylaminopropyl carbodiimide and N- hydroxysuccinimide in the case of poly (acrylic acid) and poly (allyl amine).
• etherifying agents such as, for example, acetonitrile or N, N-dimethylformamide, or imidization, such as, for example, 2-pyridone or 2- oxazoline.
• the barrier multilayer is produced by alternately depositing a cationic polyelectrolyte and an anionic polyelectrolyte in the presence of one or more crosslinking agents.
• cationic polyelectrolytes that can be used in the coating of the invention, mention may be made of polymers containing amine groups such as a poly (allylamine hydrochloride), a poly (ethylene imine) or chitosan; quaternary ammonium group polymers such as poly (diallyldimethylammonium chloride) and polyvinylbenzyltrimethylammonium chloride; and polymers with pyridine or pyridinium groups such as poly (N-methylvinylpyridine).
• amine groups such as a poly (allylamine hydrochloride), a poly (ethylene imine) or chitosan
• quaternary ammonium group polymers such as poly (diallyldimethylammonium chloride) and polyvinylbenzyltrimethylammonium chloride
• polymers with pyridine or pyridinium groups such as poly (N-methylvinylpyridine).
• anionic polyelectrolytes that may be used in the coating of the invention, mention may be made of polyacids such as a polyacrylic acid or a poly (methacrylic acid); sulfonate-containing polymers such as sulfonated poly (styrene sulfonate), polyvinyl sulfonate or poly (ether ether ketone); sulfated polymers, in particular polyvinyl sulphate; polymers with phosphonate groups or phosphates, and anionic polysaccharides.
• polyacids such as a polyacrylic acid or a poly (methacrylic acid)
• sulfonate-containing polymers such as sulfonated poly (styrene sulfonate), polyvinyl sulfonate or poly (ether ether ether ketone); sulfated polymers, in particular polyvinyl sulphate; polymers with phosphonate groups or phosphates
• the anticorrosive coating may further include an adhesion promoting layer of a subsequent surface treatment.
• This layer is preferably based on a polyelectrolyte such as, for example, one of those mentioned above.
• the term "surface treatment” is intended to mean a primer layer consisting of a charged organic matrix, generally based on epoxy.
• the primer coat is usually protected by finishing paint, epoxy or polyurethane. This last layer ensures in particular the physical barrier to the aggressions of the environment, extreme climates, UV and various pollutants, and decoration.
• the coating as described above is preferably used to improve the resistance to corrosion, scratching, scratching and rubbing, the mechanical strength, the hydrophobicity and / or the coloration of a substrate in the aeronautical field or aerospace.
• Another object of the invention is a structure comprising:
• nanostructured anticorrosion coating based on polyelectrolytes as defined above.
• the substrate may be metallic or non-metallic.
• the metal substrate which can be used in the present invention is preferably aluminum or one of its alloys such as, for example, the aluminum of the 2000 family, more particularly the plated or unplated Ai 2024, the aluminum of the family 7000, and even more particularly Ai 7075 or 7175 and aluminum of the family 6000 or 5000, or titanium or magnesium.
• non-metallic substrates examples include composite substrates, such as carbon fiber reinforced plastics (CFRP), such as, for example, thermosets or thermoplastics.
• CFRP carbon fiber reinforced plastics
• the coating as described in the present invention is compatible with all the substrates mentioned above.
• it will provide these substrates with a reinforcing property of the substrate / primary paint interface.
• the structure may further include a polyelectrolyte - based substrate adhesion layer between the substrate and the anticorrosive coating.
• the adhesion to the substrate is not only via the electrostatic interactions, but can also be done by chemical interactions such as, for example, organometallic complex bonds with the substrate.
• This substrate adhesion layer may comprise a cationic or anionic polyelectrolyte such as, for example, chosen from those defined above, and preferably chosen from anionic polyelectrolytes and better still a poly (acrylic acid).
• Another object of the invention is the use of the coating according to the invention, to improve the resistance to corrosion, scratching and friction, the mechanical strength, the hydrophobic character and / or the coloration of a metal substrate or non-metallic, in the aeronautical or aerospace field.
• the invention also relates to a method for producing a structure as defined above.
• This method of realization comprises steps of preparation of a main compartment, during which:
• the method according to the invention may further comprise a step before step (a), during which a substrate adhesion layer is deposited.
• the polyelectrolyte multilayer (s) doped with at least one anti-corrosion agent for example by co-adsorption.
• the method according to the invention may further comprise steps of preparing a secondary compartment, during which:
• step (c) depositing a multilayer doped with at least one functional agent different from an anticorrosion agent on a multilayer barrier, for example in step (b) or (d), according to the layer-by-layer technology, and
• the method according to the invention may also comprise a step in which a layer promoting the adhesion of a subsequent surface treatment is deposited.
• each multilayer is deposited using the method comprising the following steps, which consist in: (i) preparing: a first aqueous solution or containing one or more solvents such as ethanol, isopropanol or dimethylsulfoxide, preferably an aqueous solution, the first solution comprising a polyelectrolyte, and a second aqueous solution or containing one or more polar solvents such as ethanol, isopropanol or dimethylsulfoxide.
• solvents such as ethanol, isopropanol or dimethylsulfoxide
• the second solution comprising at least one oppositely charged doping agent for the polyelectrolyte of the first solution, a polyelectrolyte with a charge opposite to the polyelectrolyte of the first solution, or a mixture thereof, (ii) adsorbing a layer of the first solution prepared in step (i), on the surface to be covered, (iii) rinsing the surface in the solvent used for the first solution in order to eliminate the excess of the first solution,
• step (iv) drying the layer, especially thermally, by a jet of neutral gas such as nitrogen or filtered compressed air, or by combining the two techniques, (v) depositing a second solution prepared in step (i), (vi) rinse in the solvent used for the second solution in order to eliminate the excess of the second solution,
• a jet of neutral gas such as nitrogen or filtered compressed air
• steps (ii) to (vii) (step (viii)) are repeated from 1 to 20 times, better from 1 to 10 times, and even more preferably from 5 to 10 times.
• This repetition and the possible final execution of steps (ii) to (iv) (step (ix)) make it possible to obtain a multilayer thickness preferably ranging from 2 to 100 nm, better still from 2 to 50 nm.
• Steps (ii), (iii), (v) and (vi) described above are in particular carried out by soaking-shrinking, spraying, spraying or deposition on a rotating substrate.
• concentrations of polyelectrolyte (s) in the solutions prepared in step (i), expressed in monomers, may be in the range preferably from 10 "3 to 5 ⁇ 10 -2 mol / l (or M). .
• concentrations of doping agent (s) possibly present in the second solution prepared in step (i) may be in the range preferably from 10 to 50 g / l, more preferably from 30 to 40 g / l.
• the substrate adhesion layer and the adhesion promoting layer of a subsequent surface treatment are deposited by following steps (i) to (iv) as defined above. They preferably have a thickness preferably ranging from 1 to 20 nm, more preferably from 1 to 10 nm.
• FIG. 1 illustrates an embodiment of a nanostructured anticorrosion coating according to the invention
• FIG. 2 illustrates an embodiment of a nanostructured anticorrosion coating deposited on a metal substrate
• FIG. 3 illustrates an embodiment of a structure according to the invention.
• a nanostructured anticorrosion coating based on polyelectrolytes can be constituted by the repetition of an elementary unit, called the main compartment. As illustrated in FIG. 1, the main compartment comprises a multilayer 1 doped with anti-corrosion agents and a multilayer 2a that is a barrier against the diffusion of anti-corrosion agents.
• the multilayer 1 doped anticorrosion agent comprises a matrix 3 of polyelectrolyte (s) in which is trapped an anticorrosive agent 4 in the form of nanoparticles preferably having a size ranging from 1 to 50 nm, better from 2 to 10 nm.
• the anticorrosive agent 4 is here the doping agent.
• this polyelectrolyte multilayer 1 doped with at least one anti-corrosion agent may be produced by successive deposition of a cationic polyelectrolyte such as a poly (allylamine hydrochloride), and an anticorrosion agent in the form of oxide nanoparticles. metallic negatively charged.
• a cationic polyelectrolyte such as a poly (allylamine hydrochloride)
• an anticorrosion agent in the form of oxide nanoparticles. metallic negatively charged.
• the multilayer 2a barrier to the diffusion of doping agents comprises crosslinked polyelectrolytes.
• the multilayer 2a barrier to the diffusion of doping agents is generally performed by an alternating deposition of a cationic polyelectrolyte and an anionic polyelectrolyte in the presence of a crosslinking agent.
• the crosslinking agent makes it possible to create bridges maintained by covalent bonds between the chains of two oppositely charged polyelectrolytes. This layer leads to obtaining a compartment with reduced permeability.
• Such a multilayer 2a makes it possible to limit the diffusion of the nanoparticles of the anticorrosion multilayer towards the other functional multilayers.
• the crosslinking agent (s) are either co-adsorbed during all the deposition steps, or during some of them.
• the diffusion barrier layer can be made by alternating, for example, the deposition of a poly (acrylic acid) (PAA) and a poly (allylamine hydrochloride) (PAH) in the presence of an agent (s). ) crosslinking such as 1-ethyl-3-dimethylaminopropyl carbodiimide (EDC) or N-hydroxysuccinimide (NHS).
• PAA acrylic acid
• PAH poly (allylamine hydrochloride)
• EDC 1-ethyl-3-dimethylaminopropyl carbodiimide
• NHS N-hydroxysuccinimide
• This nanostructured anticorrosion coating can be deposited on a metal substrate. It is then desirable to promote good interfaces, on the one hand between the nanostructured anticorrosion coating and the substrate, and on the other hand between the nanostructured anticorrosion coating and the subsequent treatment layers. This is illustrated in Figure 2.
• a layer 6 of adhesion between the substrate 5 and the nanostructured anticorrosion coating according to the invention is interposed.
• the upper face of said adhesion layer 6 has properties compatible with the development of the nanostructured anticorrosion coating.
• the lower face of said adhesion layer 6 forms bonds with the surface atoms of the substrate 5. Said bonds are generally of the electrostatic type or of complexation. It should be noted that according to the chemical natures of the substrate 5 and of the polyelectrolyte used for the formation of the adhesion layer 6, organometallic complex bonds with the pendent atoms of the surface of the substrate can be obtained. In this case, the interaction between the adhesion layer 6 and the substrate 5 is better.
• layer 6 consists of an anionic polyelectrolyte such as polyacrylic acid (PAA).
• a substrate for example metal
• other methods for example a painting process.
• a layer 7 promoting the adhesion of subsequent treatment layers is deposited on the upper face of the nanostructured anticorrosion coating.
• the upper face of the layer 7 promoting the adhesion of subsequent treatment layers may be adapted so as to have properties favoring the deposition of the subsequent treatment layers. It can thus have, for example, a hydrophobic or hydrophilic character, a chemical affinity, a polar or protic character, particular chemical groups promoting polymerization or crosslinking, properties of hardness or mechanical strength.
• Layer 7 may comprise adaptive polymers, i.e. exhibiting a predefined response as a function of environmental stress such as a change in pH, temperature, ionic strength or brightness. The layer 7 thus obtained reacts to a given medium and changes its morphological characteristics or releases its dopant in a controlled manner.
• adaptive polymers are described in particular in S. A. Sukhishvili, Curr. Opin.
• polyamines and polyacids which are sensitive to pH
• copolymers containing polyelectrolyte sequences and thermo-responding sequences such as poly (isopropylacrylamide), polysaccharides such as carrageenans, or poly (diethylene glycol methyl ether methacrylate), or poly (vinyl methyl ether).
• FIG. 3 illustrates another embodiment in which the nanostructured anticorrosion coating comprises, in addition to the main compartment, two secondary compartments.
• a first secondary compartment comprises multilayers 8 and 2b
• the second secondary compartment comprises multilayers 11 and 2c.
• the layer 7 promoting adhesion is deposited on the last barrier layer, here the layer 2c.
• Each secondary compartment comprises at least one functional layer.
• functional layer is meant a layer which has outstanding properties of chemical, physical or organic. It may be, by way of example only, chemical affinity, hydrophobicity, hardness, mechanical strength, biocompatibility or bactericidal properties.
• the mechanical reinforcement multilayer 8 comprises a polyelectrolyte matrix 10 incorporating exfoliated clay leaflets 9.
• the mechanical strength properties of the exfoliated clay leaflets 9 are imparted to the entire mechanical reinforcing multilayer 8 via the polyelectrolyte matrix 10.
• Another functional agent conferring mechanical reinforcement may be used, for example, carbon nanotubes or ceramic nanoparticles.
• the multilayer 8 mechanical reinforcement can be carried out, for example, by alternating the deposition of a cationic polyelectrolyte, such as PAH, and that of exfoliated clay sheets, for example montmorillonite, or other inorganic compound exfoliable charged having adequate mechanical properties.
• a cationic polyelectrolyte such as PAH
• exfoliated clay sheets for example montmorillonite, or other inorganic compound exfoliable charged having adequate mechanical properties.
• FIG. 3 comprises another functional multilayer which is a coloring multilayer 1 1.
• a polyelectrolyte matrix 13 incorporates pigments 12, which may be organic or inorganic, in the form of nanoparticles.
• the coloring multilayer 1 1 can be made by alternating the deposition of a cationic polyelectrolyte such as PAH and an anionic polyelectrolyte such as PAA. Depending on the nature of the colored pigment, it will be co-adsorbed with the polyelectrolytes or will be introduced by diffusion into the formed multilayer.
• the colored pigment will be in the form of, for example, nanoparticles and will be, for example, NiIe blue, charged coumarines, fluoresceins, phthalocyanines, pyrenes, organic or inorganic nanoparticles whose color depends on the size.
• the different compartments are separated by diffusion barrier multilayers 2a, 2b and 2c making it possible to limit the migration of a doping agent from one multilayer to the other.
• doping agents present in this embodiment mention may be made of anticorrosion agents, mechanical reinforcing agents and pigments.
• a multilayer comprises at least one template and may include one or more functional agents.
• the process for preparing a structure according to the invention consists in depositing on a substrate several multilayers each having a distinct functional role. Each multilayer is itself produced by performing a layer-by-layer deposition method, comprising steps (i) to (ix) as described above.
• the method for producing a structure according to the invention comprises a succession of steps during which the deposition process described above is carried out with first and second deposition solutions that are different and dependent on the properties of the layers to be produced.
• the multilayer structure is formed on a substrate 5, for example aluminum, using the method described above.
• the adhesion layer 6 is a layer of polyelectrolyte (anionic or cationic) to ensure good adhesion to the substrate 5.
• the adhesion is promoted on the one hand via electrostatic interactions and on the other hand by chemical interactions .
• a layer of polyacrylic acid (PAA) can form a complex with the native oxides of aluminum.
• PAA polyacrylic acid
• the layer 6 is deposited from a polyelectrolyte solution, following the steps (i), (ii), (iii) and (iv) described above.
• the multilayer 1 doped anticorrosion agent is produced by successive deposition of a cationic polyelectrolyte such as poly (allylamine hydrochloride) (PAH) and an anticorrosion agent 4.
• PAH poly (allylamine hydrochloride)
• the anticorrosion agent can be in the form of nano- negatively charged metal oxide particles, for example CeO 2 .
• the deposition of the multilayer 1 doped anticorrosion agent is performed by performing the following steps: (i ') preparing a first solution (I) of a first polyelectrolyte, a second solution (II) of anti-corrosion agent with a charge opposite the first polyelectrolyte or a second solution (H') comprising mixing a second polyelectrolyte; charge opposite to the first polyelectrolyte and anticorrosion agent,
• a layer of the solution (I) prepared in step (i') is adsorbed on the adhesion layer 6, for example by soaking-shrinking the coated substrate, (iii ') rinsing the surface in the solvent used for the solution (I) in order to eliminate the excess of solution (I), (iv ') the layer is dried, (v') the solution (II) or (H ') is deposited prepared in the step (i '), for example by soaking-shrinking, (vi') rinsing in the solvent used for the solution (II) or (H ') in order to eliminate the excess of solution (II) or (H '), (vii') is dried,
• a multilayer thickness of polyelectrolyte (s) doped with an anticorrosion agent is obtained ranging from 10 to 100 nm, more preferably from 10 to 50 nm.
• Steps (ii ') to (vii') are repeated n times, n ranging in particular from 5 to 20, more preferably from 5 to 10 and even more preferably n is equal to 10.
• the first solution (I) may be an aqueous solution of cationic polyelectrolyte such as poly (allylamine hydrochloride) (PAH) and the second solution may be an aqueous solution (II) of negatively charged metal oxide nanoparticles or a solution (H ') of these same nanoparticles associated with an anionic polyelectrolyte such as PAA.
• PAH poly (allylamine hydrochloride)
• PAA anionic polyelectrolyte
• the diffusion barrier multilayer 2a comprising crosslinked polyelectrolytes is deposited on the multilayer 1.
• the multilayer 2a serves as a barrier to limit the diffusion of the doping agents between the different functional compartments.
• the deposition of the multilayer 2a is performed by performing the following steps:
• a first solution (III) of polyelectrolyte, for example anionic such as PAA, and a second solution (IV) of charged polyelectrolyte opposed to the first polyelectrolyte, for example cationic, such as PAH, are prepared.
• expressed in monomers are preferably in the range of 10 -3 to 5 x 10 -2 mol / l (or M), for example, it may be equal to 0.01 M in monomers.
• step (ii ) a layer of the solution (III) prepared in step (i") is adsorbed on the multilayer 1, for example by soaking-removal of the coated substrate, (iii ") the surface is rinsed in the solvent used for solution (III) to remove excess solution (III), (iv ") the layer is dried,
• step (v ) depositing the solution (IV) prepared in step (i"), (vi ") rinsing in the solvent used for solution (IV) in order to eliminate the excess solution (IV), (vii ") drying,
• a multilayer thickness 2a is preferably obtained, preferably from 2 to 50 nm, more preferably from 2 to 20 nm. Steps (ii ") to (vii") are repeated m times, m being in particular from 1 to 20, more preferably from 1 to 10 and even more preferably m is equal to 5.
• the layer deposits are, for example, in the presence of crosslinking agents 1-ethyl-3-dimethylaminopropyl carbodiimide (EDC) and N-hydroxysuccinimide (NHS). These crosslinking agents (EDC and NHS) can be added during all or only some of the deposit steps.
• EDC 1-ethyl-3-dimethylaminopropyl carbodiimide
• NHS N-hydroxysuccinimide
• the multilayer 8 of mechanical reinforcement for improving the mechanical strength is produced by successive deposits of a cationic polyelectrolyte and a mechanical strength-conferring agent 9.
• the cationic polyelectrolyte is, for example, PAH and the agent conferring a mechanical reinforcement 9 may be clay leaflets prepared from montmorillonite or other inorganic compound.
• the multilayer 8 is obtained by firstly preparing an aqueous solution of cationic polyelectrolyte and an aqueous solution of a mechanical reinforcement-conferring agent in step (i), then repeating successively p times (ii) to ( vii) as described above and performing step (ix).
• the repetition number of steps (ii) to (vii), noted here p is, for example, in the range of 5 to 20, preferably 5 to 10, more preferably p is 10.
• the multilayer 2b acting as a barrier to limit the diffusion of doping agents between the different functional compartments, is then deposited in the same manner as the multilayer 2a.
• the coloring multilayer 11 of FIG. 3 is then produced by successive deposition of an anionic polyelectrolyte such as PAA, and of a cationic polyelectrolyte such as PAH, in the presence of a pigment 12.
• the pigment 12 can be organic for example, in the form of nanoparticles.
• the pigment 12 is deposited by co-adsorption.
• To deposit such a dye multilayer 1 1 can be used for example PAH and PAA with NiIe Blue, charged coumarins or fluoresceins or other compounds such as those mentioned above. Depending on the nature of the colored pigment, it will be co-adsorbed with the polyelectrolytes or will be introduced by diffusion into the formed multilayer.
• step (i) that is to say by preparing separate aqueous solutions of PAA and PAH, followed by the succession of steps (ii) to (vii) as described. above, repeated times, then possibly performing the step (ix).
• the repetition number of steps (ii) to (vii), denoted here r is for example in the range from 5 to 20, preferably from 5 to 10, more preferably r is equal to ten.
• the multilayer 2c acting as a barrier to limit the diffusion of doping agents between the different functional compartments, is then deposited in the same manner as the multilayers 2a and 2b.
• the layer 7 promoting adhesion between the multilayer 2c and a possible subsequent treatment is then deposited.
• a layer may comprise an anionic polyelectrolyte or a cationic polyelectrolyte, and more particularly a PAH and an epoxy-based varnish.
• the deposition is carried out by successively repeating steps (ii), (iii) and (iv) as described above.
• the functional agents used in the preparation of the different layers can be grouped into a single compartment.
• a first substrate adhesion layer the substrate being for example aluminum
• a first multilayer barrier to the diffusion of doping agents a PAH-based multilayer and of clay platelets
• a corrosion agent and a dye in a compartment
• a second multilayer barrier to the diffusion of doping agents in another embodiment, can be grouped into a single compartment.

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• 2008
  • 2008-01-14 FR FR0850196A patent/FR2926302B1/fr not_active Expired - Fee Related
• 2009
  • 2009-01-08 WO PCT/FR2009/050022 patent/WO2009092940A1/fr not_active Ceased
  • 2009-01-08 US US12/812,462 patent/US20110281105A1/en not_active Abandoned
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