DE102009006942A1 - Producing polymer coated metal containing nanoparticles, comprises forming anionic macroinitiators solution in solvent, adding polymerizable monomer, polymerizing, adding sulfide, metal salt and homogeneous reducing agent and precipitating - Google Patents

Abstract

Producing polymer coated metal containing nanoparticles comprises: preparing a solution of anionic macroinitiators in an aprotic organic solvent; adding at least one anionically polymerizable monomer to the solution; anionically polymerizing at room temperature; adding aliphatic or aromatic sulfide; adding a solution of at least one organo soluble metal salt in an aprotic organic solvent; adding a homogeneous reducing agent; precipitating the obtained particles with an organic solvent; and separating and drying the particle. An independent claim is included for polymer coated metal containing nanoparticles obtained by the process.

Description

The The present invention provides a process for the preparation of Polymers coated metal-containing nanoparticles as well available particles from it. These particles can for antibacterial applications and inks be used. In the case of metals showing plasmon resonance, appropriate particles can also be used in sensors that use the plasmon resonance effect.

Description and introduction of the general field of the invention

The The present invention relates to the fields of polymer chemistry, metal processing and materials science.

State of the art

With Polymer-coated metal-containing nanoparticles find numerous technical applications. They serve, for example, the antibacterial Equipment of polymers for textiles and materials. Of Further, the plasmonone resonance effect of some metals in sensors and thermally switchable windows. Also come in inks Such metal-containing nanoparticles are used.

It are already some ways of antibacterial Equipment of polymers known. A technically well established Method of finishing polymers is incorporation of silver salts or silver nanoparticles in these polymers. By the resulting silver ions become the membranes of bacteria destroyed. However, the problem is often the Incompatibility of the polymers with the silver salts or Silver nanoparticles, which is why it then leads to mechanical defects, strong Discolouration or turbidity of the polymers comes. Remedy here provides the wrapping of silver nanoparticles Polymers for which there are different methods.

The DE 10 2006 058 202 A1 describes a process for preparing an aqueous dispersion containing at least one polymer and / or oligomer and inorganic surface-modified particles. The inorganic particles may be metal oxides, and they may be surface-modified with anionic polymers.

The DE 103 46 387 A1 describes a germicidal, silver-containing agent for antimicrobial finishing of surfaces. The germicidal composition may optionally contain one or more film-forming polymers selected from the group comprising polyacrylates, polyvinyl alcohols, polyvinyl acetals. The silver used is preferably nanosilver.

The DE 102 61 806 A1 describes polymer-stabilized nanoparticles or nanostructured composite materials. The nanoparticles can be metals. However, only those metal-containing nanoparticles which are prepared from barium salts are disclosed.

The metals silver, copper and gold not only have antibacterial properties, but they show plasmon resonance, which can be excited by the IR or UV-VIS radiation. The interaction between the plasmons in Ag is higher than in other metals, as in David D. Evanoff, Jr., George Chumanov, "Synthesis and Optical Properties of Silver Nanoparticles and Arrays" ChemPhysChem 2005, 6, 1221-1231 is described. By plasmon resonance is meant a collective vibration of all electrons of a nanoparticle. In the case of spherical particles, this acts independently of the angle of incidence and the direction of the electric field vector (E vector), ie the polarization direction. Silver is the only material able to cover the entire visual wavelength range of 400 to 800 nm by plasmon resonance, whereby the geometry of the particle (shape and size) plays a decisive role.

The above-cited essay by Evanoff et al. describes a process for the preparation of polymer-coated silver nanoparticles in which silver nanoparticles are charged; Subsequently, polystyrene or PMMA is polymerized in the presence thereof by emulsion polymerization. However, the method is useful only for a limited number of monomers and solvents as well as for relatively large silver particles (around 100 nm in diameter). The generated particles aggregrieren also fast.

The prior art knows silver particles which are coated with a polymer or incorporated therein as an additive. So describe L Quaroni and G Chumanov in "Preparation of Polymer-Coated Functionalized Silver Nanoparticles", J Am Chem Soc 1999, 121, 10642-10643 Silver nanoparticles coated with polystyrene or polymethacrylate. The coating with polystyrene or poly methacrylate was achieved by emulsion polymerization, resulting in particles with sizes between 2 and 10 nm. In DD Evanoff Jr, P Zimmerman, G Chumanov: "Synthesis of Metal-Teflon AF Nanocomposites by Solution-Phase Methods," Adv. Mater. 2005, 17, 1905-1908 , Teflon-coated silver nanoparticles are described. A very expensive fluorine-containing metal salt and Teflon are dissolved in a perfluorinated solvent, then reduced and then precipitated.

In Muriel K. Corbierre, Neil S. Cameron and R. Bruce Lennox: "Polymer-Stabilized Gold Nanoparticles with High Grafting Densities" Langmuir, 2004, 20, 2867-2873 Polystyrene-stabilized gold nanoparticles are described. The particles described are not antibacterial, have very large polydispersities, are relatively large and have many deformations.

The The present invention overcomes the disadvantages of the prior art the technique by providing a process with the metal-containing Nanoparticles without the addition of stabilizers quickly and inexpensively can be coated with polymers. To this Means are polymer-coated metal-containing nanoparticles which has the antibacterial properties of underlying metals or the plasmon resonance (in the case of silver, copper and gold), without the previously known ones Disadvantages of such particles as discoloration, cloudiness and mechanical defects of polymers or uncontrollable particle sizes and the undesirable tendency to aggregate.

task

task The invention is to provide a novel process for the preparation of To provide polymers coated metal-containing nanoparticles as well as metal-containing, polymer-coated nanoparticles, the obtainable by this method.

Solution of the task

• a) Herstellen einer Lösung eines anionischen Makroinitiators in einem aprotischen organischen Lösungsmittel,
• b) Zugabe mindestens einen anionisch polymerisierbaren Monomers zu dieser Lösung,
• c) Anionische Polymerisation bei Raumtemperatur,
• d) Zugabe eines aliphatischen oder aromatischen Sulfids,
• e) Zugabe einer Lösung mindestens eines organolöslichen Metallsalzes in einem aprotischen organischen Lösungsmittel,
• f) Zugabe eines homogenen Reduktionsmittels, falls das Redoxpotential des mindestens einen organolöslichen Metallsalzes nicht ausreicht, um ausschließlich durch das aliphatische oder aromatische Sulfid zum Metall reduziert zu werden,
• g) Ausfällen der gebildeten Partikel mit einem organischen Lösungmittel,
• h) Abtrennen und Trocknen der Partikel.

The object of providing a method for the production of polymer-coated metal-containing nanoparticles is achieved according to the invention by a method comprising the steps:

• a) preparing a solution of an anionic macroinitiator in an aprotic organic solvent,
• b) adding at least one anionically polymerizable monomer to this solution,
• c) anionic polymerization at room temperature,
• d) addition of an aliphatic or aromatic sulfide,
• e) addition of a solution of at least one organosoluble metal salt in an aprotic organic solvent,
• f) addition of a homogeneous reducing agent if the redox potential of the at least one organosoluble metal salt is insufficient to be reduced to the metal solely by the aliphatic or aromatic sulphide,
• g) precipitating the particles formed with an organic solvent,
• h) separating and drying the particles.

Surprised It was found that metal-containing nanoparticles covalently attached to growing anionic polymers can be tethered if an aliphatic or aromatic sulfide to the growing anionic Chain end is attached and then organolösliche Metal salts are added. This forms enveloped with polymers metal-containing nanoparticles.

The inventive method for the preparation of coated with polymers metal-containing nanoparticles and the resulting metal-containing, coated with polymers Nanoparticles are explained below, wherein the invention all preferred embodiments listed below individually and in combination with each other.

Under "organosoluble Metal salts "are understood to mean those salts which are in organic solvents, especially in aprotic ones organic solvents, solve. These are, for example, but not exhaustive, metal salts whose anion is selected is from the group acetates, trifluoroacetates, acetylacetonates, benzoates, Iodides and mixtures thereof. The associated metal cations act for example, but not exclusively cations of silver, copper, gold, tin, lead, chromium, zinc and mixtures from that.

Becomes used more than one organosoluble metal salt, so two or more of these metal salts are a common anion or a have common cation.

In a preferred embodiment is organosoluble Salts of antibacterial metals, for example salts of silver, copper, gold, tin, lead, chrome, zinc. Alternatively, you can these are also metal alloys, z. For example, silver / gold, Silver / copper or copper / gold alloys, or with one antibacterial metal-coated nanoparticles, z. B. Cu nanoparticles with Ag coating, Fe nanoparticles with Cu coating, magnetite nanoparticles with Ag coating, Titanium dioxide nanoparticles with Ag coating. The skilled person is Knows how he can make alloy nanoparticles. Can do this For example, mixtures of salts of two different metals simultaneously be reduced. The skilled person is also known as he with a second metal-coated nanoparticles of a first Metal can produce. He can apply this knowledge without the To leave the scope of the claims.

In a further preferred embodiment are organosoluble salts of metals that show plasmon resonance, for example, organosoluble silver, copper and gold salts.

Under "macroinitiator" or short "initiator" according to the invention substances understood that initiate anionic polymerization. These include for example, but not exhaustively, alkali metal alcoholates, Metal alkyls, amines, Grignard compounds (alkaline earth alkyls), Lewis bases and One electron transferor (eg naphthyl sodium).

Especially preferred are metal alkyls such. B. secondary butyl lithium (S-BuLi).

The aprotic organic solvents, for example, but not exhaustively selected from ethers (for example Tetrahydrofuran (THF), diethyl ether), toluene, benzene, hexane, cyclohexane, Heptane, octane, DMSO and mixtures thereof. in principle is any aprotic solvent suitable, which is the anionically polymerizable monomer, the aliphatic or aromatic Sulfide containing at least one organosoluble metal salt and the living polymer dissolves and not with the monomer or reacting chemically with the living polymer. In the sense of the present Invention means to "solve" that monomer, Sulfide, metal salt or polymer in each case to at least 0.1% by weight in the solvent or solvent mixture are soluble.

Under a "living polymer" is a polymer chain meant, which has not yet been broken off and therefore continue to react can. For example, it is known that anionic polymerization of styrene and to this "living" polystyrene other monomers or add more styrene until the reaction is stopped.

Prefers is for the solution of the anionic macroinitiator according to step a) the same solvent or solvent mixture used as for the Solution of the at least one organosoluble metal salt according to step e).

anionic polymerizable monomers are for example, but not exhaustive, Styrene (St), butadiene, isoprene, ethylene oxide, propylene oxide, caprolactone, Lactide, glycolide, acrylates, methacrylates, bisacrylates, cyanoacrylates, Amides, siloxanes, vinylpyridines, acrylonitrile. The available from it anionic polymers are polystyrene, polybutadiene, polyisoprene, Polyethylene oxide, polypropylene oxide, polycaprolactone, polylactide, Polyglycolide, polyacrylates, polymethacrylates, polybisacry late, polycyanoacrylates, polyamides, Polysiloxanes, polyvinylpyridines, polyacrylonitrile. The anionic Polymers can be linear, branched, highly branched, star-shaped, dendritic; it can also be statistical Copolymers and block and graft copolymers act.

"At least an anionically polymerizable monomer "according to step b) of the method according to the invention means that one or more anionically polymerizable monomers according to the above list can be used. Be at least two of these used anionic polymerizable monomers, so according to the invention random copolymers or block or graft copolymers. Copolymers are obtained for example, by reacting two similarly reactive monomers simultaneously be presented, which then simultaneously in the forming Nanoparticles are incorporated. Block copolymers are obtained by first one of the monomers, then the second and successively possibly further monomers are added.

In a preferred embodiment is the anionic polymerizable Monomer selected from styrene and methacrylate.

at the aliphatic or aromatic sulfide is, for example to an alkyl sulfide such as ethylene sulfide or propylene sulfide or to an aromatic sulfide such as styrenesulfide. Preference is given to ethylene sulfide.

at the homogeneous reducing agent is, for example, but not exhaustive to superhydride (lithium triethylborohydride) or hydrazine.

The aliphatic or aromatic sulfide according to step d) of the method according to the invention acts as Reducing agent for the metal salt, as it has electrons can transfer the metal cation. The person skilled in the art is aware that such a reduction of the redox potential of the metal in question is dependent. The so-called standard potentials of metal / metal salt redox couples can be read in the electrochemical series. standard potentials by definition refer to standard conditions, d. H. to a temperature of 25 ° C, a pressure of 101.3 kPa, a pH of 0 and an ionic activity of 1. Will in step e) of the method according to the invention used a metal salt, the corresponding metal loud electrochemical series is less volatile than hydrogen, so must have a homogeneous reducing agent according to step f) are added so that the reduction takes place.

In the case of metal salts whose corresponding metal according to the electrochemical series of voltages is more noble than hydrogen, the reduction force of the sulfide added according to step d) of the process according to the invention is sufficient in principle to reduce metal cations to the metal. However, it should be noted that, for example, silver cations only need one electron to be reduced to silver, while two electrons are required for the reduction of Cu ²⁺ ions to elemental copper are needed. At the same concentration of Cu ²⁺ or Ag ⁺ salt and sulfide, therefore, less Cu ^{2+ is} reduced to Cu than Ag ⁺ to Ag. It is known to those skilled in the art that the amount of reducible metal salt depends, inter alia, on the concentrations of the metal salt and the reducing agent, their respective redox potential and the number of electrons that must be transferred. If the solution of the at least one metal salt according to step e) of the process according to the invention is a sufficiently dilute solution of the salt of a noble metal, it may be that the redox potential is not high enough due to the low salt concentration to reduce the metal to expire. In this case, even when using a salt of a noble metal, the addition of a homogeneous reducing agent according to step f) is required.

In a preferred embodiment is in the at least one organosoluble metal salt around a salt or salts of metals that are nobler than hydrogen, and it becomes in step f) of the procedure according to invention added a homogeneous reducing agent.

The Precipitation by means of the invention Method formed coated with polymers containing metal Nanoparticles are made with the help of a precipitant, for example Water, methanol, ethanol, n-propanol, isopropanol, acetone, diethyl ether, Methyl acetate, ethyl acetate, hydrocarbons such as pentane, hexane, Heptane, cyclohexane, cycloheptane, petroleum ether and mixtures this solvent.

In In a preferred embodiment, the precipitation takes place with the help of water, methanol or ethanol, which is optional before acidified or with an acid salt such as calcium chloride be offset.

the One skilled in the art knows which solvents and precipitants for which polymers are suitable.

"Precipitating agent" while that solvent or solvent mixture, which for the precipitation of the coated with polymers metal-containing nanoparticles is used.

in the According to the present invention, the precipitating agent is chosen that it dissolves with the solvent in which Macroinitiator and anionically polymerizable monomer dissolved were. The precipitant is further selected that it is not the polymer formed during the reaction solves.

The inventive method can be both discontinuously (batch process) as well as continuously, for example in the microreactor.

at discontinuous implementation of the process as a batch process the preparation is carried out as described above in a single reaction vessel.

In In an advantageous embodiment, the macroinitiator and the sulfide in the ratio 1: 1 (equivalent / equivalent) used.

Of the Macroinitiator and the at least one anionic polymerizable Monomers are advantageous in the ratio of initiator: monomer = 1:10 to 1: 100 (equivalent / equivalent).

In a preferred embodiment is in the Metal salt around the salt of a noble metal, and it does not become a reducing agent according to step f) of the invention Procedure added. In this case, be 2-3 equivalents Metal salt per equivalent of the monomer used, preferably 2.3 equivalents. Furthermore, in this embodiment, As described above, one equivalent of macroinitiator and one equivaltent of sulfide per equivalent of monomer used.

In In a particularly preferred embodiment, one equivalent each Monomer, sulfide and macroinitiator and 1 to 8 equivalents each Metal salt and homogeneous reducing agent used, as well used much equivalents of metal salt as a reducing agent become.

at continuous implementation of the method, for example in a microreactor, the steps a) to d) according to the above Process prepared in a first vessel. In a second vessel becomes the solution of at least one organosoluble metal salt in one aprotic organic solvent provided. Then be these two solutions merged continuously for example, in a microreactor, and the product solution being formed continuously dissipated. The failure of the educated Particles from the product solution according to step f) takes place in a third vessel. Subsequently become the precipitated particles according to step g) separated and dried.

The polymer-coated nanoparticles according to the invention have diameters of about 2 nm to 300 nm, wherein the scattering by the mean of 30% to 70%. The have Metal particles in the inside diameter of about 1 nm to 10 nm, and the thickness of the polymer layer is about 0.5 nm to 300 nm.

It should be emphasized that all accessible by the method according to the invention, with Polymer-encapsulated metal-containing nanoparticles do not aggregate or agglomerate and therefore retain their physical and chemical properties for a very long time. For example, the particles according to the invention are UV-stable, since they can be exposed to solar radiation for several months without changing. The chemical stability could be demonstrated by exposing the particles to semi-concentrated nitric acid for several days without any change in the particles.

The inventive method allows use of the entire spectrum of anionically polymerizable monomers. The resulting particles are u. a. so stable because every polymer chain individually coordinatively bound to the metal surface.

The accessible by the method according to the invention, coated with polymers metal-containing nanoparticles can be used as non-aggregating antibacterial substances. there They can either be processed directly or as additives be added to other polymers. So can the nanoparticles directly or as additives in films or coatings, workpieces (extrudates, Pressed pieces), fibers (macro-, micro-, nanofibers, electrospun Fibers) are used. They can be used for example in antibacterial Lacquers, antibacterial textiles, antibacterial filters, antibacterial Use membranes, antibacterial components.

Of Furthermore, the inventive, coated with polymers metal-containing nanoparticles for the manufacture of inks are used. This is special advantageous if the metals are gold, silver, copper or alloys thereof. In the production of electronic Components provide an alternative to inkjet printing processes conventional photolithography. Is it the or the polymers of the nanoparticles according to the invention To thermally degradable polymers, these polymers can optionally removed after printing, for example through Pyrolysis. In this way, very thin metal lines receive. Is it the case of the invention Particles around silver particles, so can be produced silver lines, the antibacterial, electrically conductive and thermally conductive are.

A further use of with the inventive Prepared polymer-coated nanoparticles, their outer metal is silver, copper or gold is, is due to their plasmon resonance.

Of the Plasmon resonance effect can be, for example, in immunosensors in kinetics and bioanalytics: The above-mentioned invention, gold, silver or copper nanoparticles coated with polymers can adsorb foreign molecules. Through this Change in ligand envelope changes the plasmon resonance frequency of the particle. By plasmon resonance measurement Therefore, very low concentrations of foreign molecules, for example, biomolecules detected.

The coated with polymer-containing metal-containing nanoparticles, if they have a reversible thermochromic effect, the due to the changed interferences of the plasmon resonances is, furthermore in thermally switchable windows and in the sensor system be used.

Figure legends

1

1 shows TEM images (transmission electron microscopy) of silver nanoparticles, which were prepared according to Embodiment 1. In 1a ) particles are shown after stirring in an ultrasonic bath, in 1b ) such after stirring with a magnetic stirrer.

While the silver cores, which were produced by means of magnetic stirrer, are 5 nm in size ( 1b ) and individually present, those produced in the ultrasonic bath agglomerate into structures of 200 nm ( 1a ).

1a ): The bar at the bottom right of the picture corresponds to 2.6 μm.

1b ): The bar at the lower right edge of the picture corresponds to 2 nm.

2

The Structure of the core-shell particles was investigated by AFM, wherein For this analysis method particles with the molecular weight the Oligostyrolhülle of 326 g / mol were used.

Based on 2 it is possible to prove the postulated structure of the core-shell particles. The AFM images were taken at different magnifications:

2a ): Magnification Ag / St = 0.1; M = 326 g / mol

2 B ): Magnification Ag / St = 4.35; M = 326 g / mol.

St = Styrene; M = 326 g / mol refers to the molecular weight of Oligostyrolhülle.

at the lower magnification one recognizes that all particles are identically constructed, each has a nucleus (Silver) and a shell (styrene chain).

3

Shown is the antibacterial effect of films of industrial polystyrene (M _n = 100,000) and core-shell silver nanoparticles according to Embodiment 2.

3a ) shows the antibacterial effect on E. coli.

3b ) shows the antibacterial effect on M. luteus.

B ₂ denotes a blend of the above-mentioned industrial polystyrene and core-shell silver nanoparticles having a molecular weight of the shell polymer of 326 g / mol. The weight ratio of the blend is 12 to 88.

B ₄ denotes a blend of the above-mentioned industrial polystyrene and core-shell silver nanoparticles having a molecular weight of the shell polymer of 1980 g / mol. The weight ratio of the blend is 11 to 89.

B ₆ denotes a blend of the above-mentioned industrial polystyrene and core-shell silver nanoparticles having a molecular weight of the shell polymer of 116590 g / mol. The weight ratio of the blend is 14 to 86.

4

4 shows an SEM image of the polystyrene film with core-shell silver nanoparticles according to Embodiment 2.

Of the white bars at the bottom right of the picture correspond to 600 nm.

5

TEM of microreaction synthesized silver nanoparticles with polystyrene shell.

5 shows an overview of several polymer drops on the edge of a grid hole. The silver particles are weakly recognizable in the drops.

Of the Scaling bar at the upper right edge of the picture corresponds to 100 nm.

6

TEM of microreaction synthesized silver nanoparticles with polystyrene shell.

6 shows a single polymer droplet with several silver particles. The scaling bar at the upper right edge of the picture corresponds to 5 nm.

7

TEM of microreaction synthesized silver nanoparticles with polystyrene shell.

7 shows a single silver particle with recognizable lattice planes. The scaling bar at the lower left edge of the picture corresponds to 1 nm.

8th

TEM of silver particles with polystyrene or polymethacrylate sheath. The scaling bar at the top right of the screen is 50 nm.

9

UV-VIS spectrum A. uncoated and B: polystyrene coated silver particles in water (solid line) or 1.8 M NaCl solution (dashed line).

10

TEM of silver particles in teflon. The scaling bar at the bottom right Image border corresponds to 30 nm.

embodiments

Embodiment 1

Production of polystyrene coated silver nanoparticles

The Mixing of the reaction solution was carried out with the aid of a magnetic stirrer or ultrasonic bath guaranteed. In a flask were 10 ml THF with initiator (s-BuLi / cyclohexane 1.3 M) submitted. The Reaction temperature was 25 ° C. The polymerization was started by the rapid addition of the monomer (St). The solution immediately turned dark red. After complete Polymerization (about 5 minutes) was the mixture with an ethylsulfide-THF solution added. The color disappeared after a few seconds. Subsequently a solution of silver trifluroacetate in THF was added and the reaction mixture stirred for 10 min. The resulting Particles were precipitated from methanol. After the precipitated Samples were filtered, they were at 60 ° C in a vacuum oven dried for 20 h.

The size of the particles was determined by TEM (Transmission electron microscopy) and AFM (atomic force microscope) clarified. The particle sizes were dependent on silver content and production method between 3 and 200 nm.

The TEM images of the particles are in 1 shown.

The structure of the core-shell particles was investigated by AFM. This is in 2 shown.

Embodiment 2:

Antibacterial effect of the core-shell particles

Due to the composition of the core-shell particles (silver core) an antibacterial effect was suspected. For this reason, films were made of industrial polystyrene (M _n = 100,000) and the particles:
From industrial PS (M = 100,000) and core-shell nanoparticles in THF, a solution was prepared. With this, the bottom of a Petri dish was poured or pulled with a squeegee on a glass plate, a film and allowed to stand for 20 h to dry out the solvent. The film was peeled off and used for further investigation.

The antibacterial effect of the polymer films was tested against E. coli (Escherichia coli) and M. luteus (Micrococcus luteus). It could be stated that the films have an antibacterial effect due to the emission of silver ions. However, their concentration is insufficient to completely inhibit the growth of M. luteus. This is in 3 shown.

The polystyrene shell around the silver core complicates the release of the silver ions due to the strong hydrophobicity. The fact that these are separated at all, is related to the structure of the film surface. The core-shell particles are defying the low concentration on the surface of the film ( 4 ), which facilitates the interaction with water and thus makes the antibacterial effect possible.

Embodiment 3

Synthesis of polystyrene-coated silver nanoparticles via microreaction plant

a) Synthesis of the macroinitiator

One heated in a vacuum 25 mL nitrogen flask under argon with 10 mL cyclohexane (distilled over calcium hydride) and 6.5 butyllithium (1.3 mol / L in cyclohexane, 8.5 mmol) and charged heated to 40 ° C with stirring. 2 mL styrene (distilled over calcium hydride, 17 mmol) are added quickly. The solution immediately turns deep red. The solution is stirred for a further 10 minutes at 40 ° C and until stored for use at -20 ° C.

b) Synthesis of the thiolate-functionalized polystyrene

One heated in a vacuum 1 liter nitrogen flask under argon with 400 mL THF (dried over potassium hydroxide, distilled over Phosphorus pentoxide). It is stirred at 25 ° C so much macroinitiator solution added until the red color remains, then another 26 mL (11.9 mmol) macroinitiator added. 15.5 mL of styrene (135 mmol) are added quickly, the deep red Solution is stirred for a further 10 minutes at 25 ° C. The solution is treated with 0.71 mL of ethylene sulfide (12 mmol), which then takes on a pale yellow color. The solution is stored at -20 ° C until use.

c) Preparation of the silver trifluoroacetate solution

3.06 g of silver trifluoroacetate (11.9 mmol) under argon in 446 ml of THF _abs . solved. The solution is protected from light until used with aluminum foil and stored at -20 ° C.

d) Construction of the microreaction plant

Two Syringe pumps (Syknm S1610, Teflon pump head, internal volume the glass syringes each 10 mL) are over stainless steel cannulas with a pressure sensor and a microreactor (Ehrfeld LH25, mixing plate 50/50 μm, blend plate 50 μm). The exit of the microreactor is filled with a stainless steel cannula (length about 2 meters, internal volume 1.92 mL).

e) carrying out the synthesis via microreaction

Both syringe pumps are initially filled with 500 mL water, 500 mL THF, 150 mL cyclohexane and 300 mL THF _abs . rinsed to remove any contaminants. Pump 1 is rinsed with 180 mL of the solution of the functionalized polymer (solution 1), and pump 2 is rinsed with 180 mL of the silver trifluoroacetate solution (solution 2). The pumps are set to the respective pumping speed and switched on. 5 ml of the product solution are discarded, 40 ml of the product solution are collected in a vessel. The product is precipitated in 400 ml of methanol, aged for 2 hours, filtered off and dried in a vacuum oven at 60 ° C. overnight.

Example of pumping speeds Approach SB160508-2:

Polystyrene solution (solution 1): 10.00 mL / minute Silver trifluoroacetate solution (solution 2): 13.20 mL / minute For other approaches, the pumping speeds are varied as needed.

In 5 to 7 TEM images of microreaction synthesized silver particles with polystyrene shell are shown.

Embodiment 4

Preparation of poly (styrene-block-co-MMA) -Ag with magnetic stirrer

20 mL THF were heated to 25 ° C in a water bath. The according to 3.a) freshly synthesized macroinitator solution (c = 0.5 mol / L) was added to the THF until the red color of the macroinitiator was stable. Thereafter, another 0.65 mL of macroinitiator (c = 0.50 mol / L, 0.33 mmol, 1.00 eq.) Was added to the solution. 3.01 g of styrene (3.4 mL, 28.9 mmol, 87.58 eq) became fast given to the solution. After five minutes, 90.1 mg of 1,1-diphenylethylene (0.50 mmol, 1.5 eq.) to the deep red Solution given. After another five minutes were 460.6 mg of methyl methacrylate (0.49 mL, 4.60 mmol, 13.94 eq.). given to the solution. After another five minutes were added 50.0 mg of ethylene sulfide (0.84 mmol, 2.48 eq.) Solution given. The solution was mixed with 10 mL silver trifluoroacetate solution (c = 34.9 mmol / L, 0.349 mmol, 1.06 eq. in THF). After five minutes, the solution became ten-fold excess Methanol introduced. The brown precipitate was filtered off, washed with water and methanol and for 12-16 h in a vacuum oven at 60 ° C dried.

The obtained particles were measured by transmission electron microscopy examined. For this purpose, a device JEM 3010 JEOL used. The measurements were made with a LaB6 crystal as the cathode recorded at a voltage of 300 kV. The sample preparation was done on 300 mesh copper grids with graphite coating by immersion in a highly diluted chloroform dispersion of nanoparticles and drying in air.

The evaluation was carried out with the device's own program Gatan Digital Microscope and the program ImageJ, version 1.40 g from the National Institute of Health, USA. Per sample diameter of 100 to 150 particles were measured. The average diameter and standard deviation were determined using the OriginPro 7.5 program.

Average diameter of the particles according to Embodiment 4: 4.3 nm
Standard deviation: 1.5 nm (35%)

Embodiment 5:

Polystyrene-clad copper nanoparticles

A solution of thiolate-functionalized polystyrene was prepared as described above (approach 150508-2, Mn = 4400 g mol-1, c = 11.1 mmol / L). To 10 mL of this solution (0.11 mmol, 1.00 eq.) Was added 71 mg of copper (II) acetylacetonate (0.27 mmol, 2.47 eq.) In 10 mL of THF. The solution was mixed with 1 mL hydrazine solution (c = 1 mol / L in THF, 1 mmol, 9.35 eq.). The resulting white precipitate was filtered off and discarded. The solution was placed in ten times excess methanol. The colorless product was filtered off, washed with water and methanol and dried in a vacuum oven at 60 ° C overnight.
Yield: 263 mg (52%)
The particles according to embodiment 5 were investigated by means of transmission electron microscopy as described under example 4.
Average diameter of particles according to Embodiment 5: 2.2 nm Standard deviation: 0.6 nm (27%)

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 102006058202 A1 [0005]
• - DE 10346387 A1 [0006]
• DE 10261806 A1 [0007]

Cited non-patent literature

• - David D. Evanoff, Jr., George Chumanov, "Synthesis and Optical Properties of Silver Nanoparticles and Arrays" ChemPhysChem 2005, 6, 1221-1231 [0008]
• - Evanoff et al. [0009]
• - L Quaroni and G Chumanov in "Preparation of Polymer-Coated Functionalized Silver Nanoparticles", J Am Chem Soc 1999, 121, 10642-10643 [0010]
• - DD Evanoff Jr, P Zimmermann, G Chumanov: "Synthesis of Metal-Teflon AF Nanocomposites by Solution-Phase Methods", Adv. Mater. 2005, 17, 1905-1908 [0010]
• Muriel K. Corbierre, Neil S. Cameron and R. Bruce Lennox: "Polymer-Stabilized Gold Nanoparticles with High Grafting Densities" Langmuir, 2004, 20, 2867-2873 [0011]

Claims (8)

Enveloped process for the preparation of polymers metal-containing nanoparticles, comprising the steps: a) manufacture a solution of an anionic macroinitiator in one aprotic organic solvents, b) Add at least an anionic polymerizable monomer to this solution, c) Anionic polymerization at room temperature, d) addition of a aliphatic or aromatic sulfide, e) adding a solution at least one organosoluble metal salt in one aprotic organic solvents, f) addition of a homogeneous reducing agent, if the redox potential of at least an organosoluble metal salt is insufficient to exclusively by the aliphatic or aromatic Sulfide to be reduced to the metal g) failures the formed particles with an organic solvent, H) Separating and drying the particles. Process according to claim 1, characterized characterized in that it is the at least one organosoluble Metal salt around a salt of silver, copper, gold, tin, lead, chromium, Zinc and mixtures thereof. Method according to one of the claims 1 or 2, characterized in that it is at least an organosoluble metal salt around an acetate, trifluoroacetate, Acetylacetonate, benzoate, iodide or mixtures thereof. Method according to one of the claims 1 to 3, characterized in that the anionic macroinitiator is selected from alkali metal alcoholates, metal alkyls, Amines, Grignard compounds (alkaline earth alkyls) and Lewis bases. Method according to one of the claims 1 to 4, characterized in that the anionic polymerizable Monomer is styrene or methacrylate. Method according to one of the claims 1 to 5, characterized in that the aliphatic or aromatic Sulfide is selected from ethylene sulfide, propylene sulfide and styrene oxide. Metal-containing nanoparticles coated with polymers, obtainable by methods according to one of claims 1 to 6. Use of polymer-coated metal-containing Nanoparticles according to one of the claims 1 to 7 for antibacterial equipments, for the plasmon resonance measurement or for the production of Inks.