WO2009112382A1 - Redispersible functional particles - Google Patents

Abstract

A novel class of layered microparticles comprises a thermoplastic or crosslinked polymeric core containing anionic functional corona groups bonded to the core particle surface, and an oxidatively polymerized shell such as a polypyrrole embedded in the corona. The particles are useful e.g. as conductor material or electrophoretic or colloidal dye; they may be dried and redispersed in polar solvents by conventional means without changing the particles' properties.

Description

Redispersible Functional Particles

The present invention pertains to novel functional particles, to a process for the preparation of these particles, and to the use of these particles for the preparation of conductive structures, electronic devices such as OLEDs, or their use as conductor, conductor- precursor, electrochromic (dye) particles, IR absorbers e.g. in optical or acustic filters, electronic devices or light managing systems.

Conductive layers (like ITO (=indium-tin oxide) or ATO (=antimony-tin oxide)) in today's electronic devices are usually applied by PVD (physical vapour deposition) or CVD (chemical vapour deposition) which are expensive and slow procedures and usually work only on rigid and flat substrates like glass. Conductive organic polymers are so far not used because of lack of processability and stability and - often - too low conductivity and lack of transparency, with one exception: PEDOT:PSS is used as hole injection and smoothening layer, e.g. in OLED devices. However, the solution of this material is highly acidic and can "corrode" other layers, which has a negative impact on life time of the device. Furthermore, the product is delivered as diluted aqueous solution and cannot be isolated as powder.

WO 01/92377 discloses the preparation of an electrically conductive microgel containing a conductive polymer physically adsorbed onto core particles.

It has now been found, that particles having strongly improved properties such as stability, narrow size distribution, colloidal properties such as redispersability, properties of films containing the particles or formed by the particles such as adhesion of the film to the substrates, roughness of the films, electrical and optical property of the film, may be obtained by bonding a corona comprising an anionic polyelectrolyte (e.g. comprising sulfonate groups, which may be attached by reaction with styrene sulfonate), and optionally further neutral groups, to the particle surface, and depositing on and/or embedding into said corona a functional polymer shell obtained by oxidative polymerization.

The invention thus provides a layered particle comprising i) an organic polymer core containing ii) (a corona of) anionic groups and iii) an oxidatively polymerized functional polymer shell, which particle is characterized by its easy redispersability. The anionic corona, first of all, serves to balance the largest part, or all, of the positive charge resulting from the oxidative polymer shell. The particles obtained in this way contain an excess of anionic groups and/or some sterically protruding neutral groups

(such as polyethyleneoxide) in addition to the anionic groups, which render the particles redispersible in the medium.

The net negative charge of the particles and/or bulky neutral groups prevent agglomeration and provide excellent redispersability even of of a previously concentrated or dried particle material.

Unlike prior art materials using one-step preparations (e.g. EP-A-1780233), the present particle core and particle shell, and usually the intermediate corona, each are obtained in separate steps; thus, a clear structuring of the particle can be achieved (generally no shell or corona material within the core, and no core material within the particle's shell).

The layered particles of the invention contain anionic moieties usually chemically bonded to the surface of an organic polymer core. The dried particles are easily redispersible in a polar solvent, e.g. as listed further below, by conventional means, such as stirring and/or ultrasonic treatment of a mixture of the particles and a polar solvent; no aggregation of the redispersed particles, no additional treatment such as freeze drying is required.

For example, a layered particle of the invention may be formed by oxidative (Ox) polymerization of pyrrole (Py) in the suspension of core/shell particles with polyelectrolyte corona, retaining an anionic corona of the composite particle as shown in Fig. 9. Optionally, the present particles may contain further functional groups covalently bonded to the core particle (see Fig. 10), e.g. to enhance electrosteric or steric properties to prevent agglomeration/flocculation and to retain colloidal stability. As indicated in Fig. 9 and 10, preferred particles retain a fraction of the corona groups on their surface even after the shell formation step.

The particles of the invention show only minor or no tendency towards aggregation (e.g. less than 40 % b.w., especially less than 10 % b.w., of aggregated particles after renewed formation of a dispersion). The dimensions typically are in the nano scale, e.g. ranging from 5 to about 200 nm, especially from about 15 to about 100 nm. In contrast to some previously reported core shell particles, the present particles generally do not contain any low molecular stabilizer. This contributes to the particles' long time stability in the dispersion medium, and also to their redispersibility as dry powders.

Advantages of films formed by such kind of core shell particles include: a) high optical transparency (due to the dilusion effect of the core polymer); b) high adhesion of the film to the substrates (because usually no surfactants are used) and good film formation (low roughness) due to plasticity of the particle core; c) highly economic due to the incorporation of the core polymer.

Advantages of the present particles include adaptation of properties listed below:

1. Mechanical Properties tensile elongation elongation at break elastic deformation (incl. temperature dependent) creep behaviour hardness

2. Electrical Properties conductivity (incl. temperature dependence thereof; dc-conduction) impedance (incl. frequence dependence thereof; ac-conductivity) aging (incl. temperature dependence) in vacuo in air (dry) dependence from water content (NMR) of layer between ITO and organic layer voltage strain (electrotransport properties) homogenity, local variation of conductivity (STM)

3. Optical Properties transmission 400 - 800 nm aging behaviour of transmission Light scattering (translucency, haze) reflectivity

4. Chemical Properties / Processing Properties - A -

thermal stability/degradation/crosslinking solubility in various media, viskosity etc. crosslinkability structuring using common methods mechanical (e.g. embossing) thermal (e.g. laser) photochemical swelling behaviour, solvent retention

(low) reactivity with neighbouring layers

5. Interface Properties adhesion to ITO adhesion to organic layers wettability of film (contact angle) (low) roughness of film

6. General Application Properties

Particle size and size distribution (ca. 30-100 nm)

Stability of conductivity (indefinitely)

Water content (low) and pH of the material ("neutral")

Dispersibility of the polypyrrole in organic solvents (also in the context of printing)

Transparency and film forming properties of the layer

Hydrophobicity (high)

Solvent resistance (high)

HOMO level (electron blocking)

The particles may advantageously be obtained by emulsion polymerization (e.g. seeded emulsion, mini-emulsion etc.). The prodicts are narrowly dispersed (= very uniform in size and composition); their size can be adjusted in a very broad range, from a few nm to tens of micrometer (preferred are small particles < 100 nm). Composition and weight ratio of core and shell can be varied in a wide range like 1 :100 to 100:1. Also mixture of particles with different size and compositions can be used and are even preferred to get good film formation and dense packing. The particles can isolated as dry powder and easily re- dispersed. They can be applied as dry powder or preferably as dispersion in a wide range of solvents: Inks can be easily formulated which are well suited for printable electronics. The films/prints can be annealed later on to get rid of solvents and to increase packing and conductivity. Further additives like light- and heat-stabilizers, dispersants, smoothening agents etc. can be used in the dispersion or in the core material to improve film formation and final properties.

Core Particles

The core particles may be obtained according to methods known in the art for the preparation of polymer particles, e.g. by emulsion polymerization (for example, a monomer - starved semibatch emulsion polymerization may be used with advantage since it requires usage of lower amounts of surfactants for the core particle formation). The polymers are usually synthetic, examples are listed further below. For a number of applications of the final particles, a soft particle core, or a particle core which softens or melts at relatively moderate temperatures (e.g. below 200⁰C, especially below 150⁰C), is advantageous. For example, an organic polymer forming the core is crystalline or amorphous at 20°C and has a glass transition temperature of 150⁰C or lower. Soft core particles of this type usually comprise, or even consist of, thermoplastic polymers which are usually non-halogenated and non-ionic, or potentially similar organic polymers having a low degree of crosslinking, which are crystalline or amorphous at 20°C, and have a glass transition temperature of 200°C, especially 150⁰C or lower (e.g. non-ionic olefinic polymers such as polystyrene, polyacrylics like poly(meth)acrylate or copolymers thereof, allylethers). If desired, crosslinking of the core may be effected by copolymerization with suitable bi- or polyfunctional mono- or oligomers, e.g. divinylbenzene, butadiene etc.

For the sake of clarity it is added that the soft core polymeric material generally does not comprise anionic functional moieties. Still, anionic monomers may already be present during (co)polymerization of the core particle in minor amounts (e.g. less than 50% b.w. of monomers, preferably less than 20% b.w., especially less than 10% b.w. of monomers; examples are (meth)acrylic acid anions or minor amounts of sulfonated styrene), their presence, however, is not necessary at this stage.

The core particle obtained at this stage usually is from the size range of about 5 to 100 nm, especially 10 - 60 nm. Corona

Anionic and, if desired, further functional groups attached to the particle by copolymerization of the core particle with suitable functional monomers form the particle's "corona". Functional monomers may already be added before or during formation of the core particle. Alternatively, a core particle obtained as described above may be functionalized by copolymerization with one or more monomer(s) providing the anionic functionality and, optionally, further monomers.

The corona usually comprises a plurality of anionic functional groups selected from carboxylate, phenolate, complex anions and especially sulfonate and/or phosphonate groups.

In some preferred particles, one or more anionic functional groups are attached to the core particle in the form of a homopolymer chain comprising monomer units of anionic or potentially anionic functionality, or a corresponding copolymer chain containing further comonomer and/or crosslinker units. Examples for useful polyanionic chains are those obtained by co-oligomerization/ polymerization of suitable monomers providing anionic functionality with the core particle.

Monomers providing anionic functionality are mainly those of formula

PG-Sp-Ra wherein

PG stands for a polymerizable group, IiIe a vinyl group -CH=CH₂ or halovinyl group, especially a vinyl group;

Ra is a residue providing anionic functionality selected from -COOX and especially -SO₃X, -P(O)(OX)₂;

Sp is a direct bond or suitable spacer of valency (a+1 ) comprising 1 to about 50 carbon atoms, Sp being especially selected from alkylene, cycloalkylene and arylene groups and their combinations and such groups interrupted by oxygen or sulphur or nitrogen and/or substituted by O, S;

X is a radical suitable for dissociation as a cation; examples for such radicals are H, M, R₁, N(Ri)₄, wherein M stands for one equivalent of a metal, e.g. an alkali or alkaline earth metal or zinc, and Ri stands for a C₁-C₂0 hydrocarbon residue such as CrC₈alkyl, especially with styrene sulfonic acid or a suitable salt or ester thereof.

Examples for preferred monomers of this class include acids along with their esters and salts selected from vinylbenzenesulfonic, C₂-C8alkenylsulfonic, (meth)acryloyloxy-C₂-C₈alkyl- sulfonic, (meth)acryloylamido-C₂-C₈alkyl-sulfonic, vinylbenzenephosphonic, C₂-

C₈alkenylphosphonic, (meth)acryloyloxy-C2-C₈alkyl-phosphonic, (meth)acryloylamido-C₂-

C₈alkyl-phosphonic derivatives.

If esters are used, these are preferably converted into the corresponding anionic moieties

(acids or especially salts) before carrying out the final step described below (deposition of the shell).

Examples for suitable anionic monomers or those convertible into anionic moieties include:

wherein potassium ions may also be replaced by other suitable cations such as sodium, the acryloyl residue may alternatively be replaced by methacryloyl, and R'i is selected from H, a suitable cation, or preferably is as defined for R₁ above.

The grafting density of anionic chains on the particle surface often is from the range 0.001 to about 1 chain per nm².

Further monomers may be copolymerized/attached to the particle core in the same way; these comonomers may serve to adapt further properties of the final particle such as hydrophilicity/hydrophobicity, solution properties, electrostatic or steric properties, rigidity/stability of the corona (e.g. by crosslinking among the moieties forming the corona). Such further comonomers for the formation of the corona basically are chosen from the group provided for the formation of the core particle, provided that the dispersion medium is suitable as a solvent for the desired product. Preferred comonomers of this class include (meth)acrylic acid along with their salts and esters such as acrylates and methacrylates e.g. of (poly)ethyleneglycol, etherified poly(ethyleneglycol) or polyetheralcohols of various (poly)ether/polyglycol chain lengths (e.g. comprising 1-400, especially 2-100 monomer units); or divinylbenzene, butadiene for crosslinking.

The copolymerization reaction for the formation of the corona is preferably carried out in the liquid phase in presence of a polar solvent or dispersing phase. The reaction may be carried out as radical polymerization, preferably initiated by addition of a radical starter and/or application of heat and/or actinic radiation. In a typical reaction, an uncharged or charged core particle as described above is dispersed in a polar solvent. After addition of the monomer providing anionic functionality (preferably on 100 pbw of the core particle in an amount ranging from 1 pbw to about 10000 pbw) and further optional components such as comonomer(s), surfactant(s) etc., the copolymerization is initiated by application of heat (e.g. 50-100⁰C, inert gas, stirring) and/or addition of a polymerization initiator such as a radical starter.

Copolymerization reactions are carried out according to methods known per se, e.g. by addition of suitable monomers to the dispersion of core particles under conditions initiating the desired reaction. In case that ethylenically unsaturated monomers are used (especially those wherein PG stands for vinyl), the reaction may conveniently be initiated by addition of a radical starter.

The ratio of corona-forming monomer to core particle starting material (dry mass) often is from the range 0.02 : 1 to about 1000 : 1 (parts by weight).

Each of the copolymerization reactions may be carried out in presence of crosslinking agents such as monomers containing 2 or more vinyl moieties ("hydrogel corona"; examples: divinylbenzene, butadiene, di- or tri-(meth)acrylates, photo- or thermal degradable crosslinkers). The ratio of crosslinking agent, if present, to corona-forming monomer often ranges from 0 (no crosslinker) to about 0.05 : 1 (parts by weight).

The material obtained already contains negative charges on its surface; work-up may follow procedures known in the art including isolation and/or drying of the intermediate particles.

For the subsequent step (shell formation), isolated/dried particles thus obtainable may be redispersed, or the particle dispersion as obtained may be used as such. For example, a suitable core nanoparticle of thermoplastic or slightly crosslinked organic polymer, such as a polymer which is crystalline or amorphous at 20⁰C and has a glass transition temperature of 150⁰C or lower, especially polystyrene, thus may be subjected to copolymerization with a suitable monomer containing functional groups SO₃H, SO₃M or SO₃Ri, wherein M stands for one equivalent of a metal cation and Ri stands for a C₁-C₂0 hydrocarbon residue such as Ci-C₈alkyl, especially with styrene sulfonic acid or a suitable salt or ester thereof, and the sulfonic groups, especially SO₃H and SO₃Ri if introduced, are optionally converted into SO₃M, especially SO₃Na, in a subsequent step.

The optional conversion of esters and/or acids into corresponding salts is usually effected by reaction (hydrolyzation) of the ester with a strong base, e.g. an alkaline hydroxyde such as aq. NaOH, which is usually applied as an aqueous solution with or without additional heating step.

Shell

To the particle dispersion obtained in the previous step, or after redispersing the particles in a suitable polar solvent, monomers may be added which are suitable for oxidation polymerization (also known as oxidative coupling). Polymerization with deposition of the corresponding oxidation polymer takes place after reaction with a suitable oxidant such as metal cations (especially iron(lll)), peroxo compounds such as peracids, peroxodisulphates (e.g. ammoniumperoxodisulphate), H₂O₂. While providing the polyelectrolyte functionality for the conductive polymer shell, the corona functionality is retained after this shell formation step; particles thus remain easily redispersible.

For example, a pyrrole is polymerized on the surface of the particles, which is often achieved by addition of //^~\ and a suitable oxidant such as an Fe(III) salt, FeCI₃, iron(lll) tosylate.

N H

Further examples of suitable monomers for this step include aniline, thiophene, acetylene, and substituted derivatives (with substituents e.g. selected from lower alkyl such as d- Cβalkyl) known to undergo oxidative polymerization. The amount of oxidation polymer (shell) on the particle usually is at least 5 % by weight (e.g. 5-90% b.w.) of the final particle.

In a preferred process, the dispersion obtained after the above oxidation step is then subjected to desalination, e.g. by ultrafiltration.

General preparation

The invention further pertains to a process for the preparation of the present layered particles. In general, this process comprises polymerization of a suitable monomer such as pyrrole, in the presence of a polar solvent and intermediate particles dispersed in said solvent, by addition of an oxidizing agent (such as iron-Ill in case of pyrrole deposition). Intermediate particles are the present core particles including anionic corona as described above, i.e. particles comprising a thermoplastic or crosslinked polymeric core containing anionic functional groups covalently bonded to its surface.

The particles obtained in this way are usually in form of dispersions; before use or storage, these are often subjected to a desalination step (e.g. ultrafiltration, ion exchange).

The intermediate particles used in the above process steps are typically prepared by emulsion polymerization of an ethylenically unsaturated monomer to form a core particle. As described above, a suitable comonomer containing carboxylate or especially sulfonate or phosphonate groups is used concomitantly to provide the anionic functionality; examples are acids, or their esters or salts, selected from vinylbenzenesulfonic, C₂-C₈alkenylsulfonic, (meth)acryloyloxy-C₂-C₈alkyl-sulfonic, (meth)acryloylamido-C₂-C₈alkyl-sulfonic, vinylbenzenephosphonic, C₂-C₈alkenylphosphonic, (meth)acryloyloxy-C₂-C₈alkyl-phosphonic, (meth)acryloylamido-C₂-C₈alkyl-phosphonic derivatives. This comonomer may be added during the polymerization step forming the core particle and/or copolymerized with the core particle in a subsequent step to form the corona (see above). Electroneutral groups such as acid, ester, salt groups often are converted into the corresponding anionic group in a subsequent step, e.g. by addition of a base (e.g. alkaline hydroxide) and/or ion exchange. A chain transfer agent may be present to regulate the molecular weight. Purification of each step may be effected by known methods such as precipitation, ultrafiltration (UF) or other methods. Optional use/addition of crosslinking agents, usually in minor amounts, is as described above (see sections Core Particles and Corona).

Some preferred particles comprise a core of uncrosslinked or crosslinked polystyrene or poly(meth)acrylate or copolymers thereof, characterized by a low Tg, a corona of crosslinked polystyrene-sulfonate, and the shell of polypyrrol. Ratio core : corona often ranges ca. from 1 :0.5 to 1 :10 (e.g. about 1 : 2); the ratio of particle : conductive shell often ranges ca. from 1 :0.1 to 1 :1 (e.g. about 1 :0.3).

In an advantageous process, the core particle essentially consists of a synthetic organic polymer, which is crystalline or amorphous at 20⁰C and has a glass transition temperature of 150⁰C or lower, especially polystyrene. This may be converted into the final particle by carrying out the following steps subsequently:

a) copolymerization with a suitable monomer containing functional groups SO₃H, SO₃M or SO3R₁, wherein M stands for one equivalent of a metal cation and Ri stands for a C₁-C₂0 hydrocarbon residue such as Ci-C₈alkyl, especially with styrene sulfonic acid or a suitable salt or ester thereof,

b) optionally converting the sulfonic groups, especially SO₃H and SO3R₁ introduced in step (a), if present, into SO₃M, especially SO₃Na, and

c) polymerizing pyrrole on the surface of the particles.

In a specific process of this type, i) steps (a), (b) and (c) are carried out in a dispersant selected from water and polar organic solvents and mixtures thereof; ii) the conversion of sulfonic acid or sulfonic ester groups of step (b), if any, is carried out by introduction of alkaline hydroxide such as NaOH; iii) the polymerization of step (c) is carried out by addition of //^~\ and a suitable oxidant

N H such as an Fe(III) salt, FeCI₃, iron(lll) tosylate; iv) the dispersion obtained after step (c) is subjected to desalination (d), e.g. by ultrafiltration. In each of the above processes, the copolymerization step (a), forming the corona, may be carried out in presence of a crosslinker as described further above.

In general, there is no dopant or surfactant used or present during the shell deposition reaction.

The particles thus obtainable may be dried (e.g. by freeze drying or evaporation of the solvent, e.g. under reduced pressure) or stored as dispersion in the polar solvent.

The subject of the invention thus includes particles as well as particle dispersions obtainable in a process as described above.

A preferred particle dispersion comprises layered particles containing a soft core of a synthetic organic polymer, which is crystalline or amorphous at 20⁰C and has a glass transition temperature of 150⁰C or lower (with or without plasticizer), especially polystyrene, and a polypyrrole shell, characterized in that the number average diameter of the dry particles is from the range 20 to 120 nm. The particles of the invention usually are obtained with a narrow size distribution; thus, in apreferred particle dispersion at least 90% or more of the particles in the dispersion are of a diameter within a range of 10% above or below the number average diameter; also preferred are particles or particle dispersions wherein the standard deviation of particle diameter (as determined by TEM) is less than about 30%, especially less than about 25% of the mean particle diameter. More preferred particles, especially for electronics such as OLEDs, have particle sizes below 100 nm, e.g. from the range 5-60 nm.

Definitions and general conditions

"Excess negative charge" on the particle refers to an amount of anionic groups which exceeds the one of cationic groups (if such cationic groups are present). In effect, the anionic groups on the surface dissociate from their counter cations in suitable environments.

Counter cations or "free cations" are cations which may dissociate from the anionic group, preferably selected from protons or especially alkali, ammonium or phosphonium cations. Where not stated otherwise, particle sizes are given as hydrodynamic radius (Rh, determined by dynamic light scattering (DLS)). Dry particle diameters are determined by TEM.

Polar liquids for use as solvents and/or dispersing medium, especially for preparing and/or (re)dispersing the present particles, include water; alcohols including mono-, di- or polyhydric alcohols; ethers; esters; carboxylic acids and/or anhydrides; ketones; amides; amines; ionic liquids. Examples are water, ethanol, methanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, tert.-butanol, pentanol, cyclopentanol, cyclohexanol, glycol, glycerine, dimethylether, diethylether, methyl-butylether, furane, dioxane, tetrahydrofuran, acetone, methyl-ethyl- ketone, methyl-butyl-ketone, cyclopentanone, cyclohexanone, pyridine, piperidine etc. as well as mixtures thereof, or mixtures containing the polar solvent in admixture with a less polar cosolvent.

Dispersants selected from water and polar organic solvents as noted above are preferably employed for the corona formation step and for the shell formation step.

Polymers useful for preparing the core particle may, for example, be selected from the following ones:

1. Polymers of monoolefins and diolefins, for example polypropylene, polyisobutylene, po- lybut-1-ene, poly-4-methylpent-1-ene, polyisoprene or polybutadiene, as well as polymers of cycloolefins, for instance of cyclopentene or norbornene, polyethylene (which optionally can be crosslinked), for example high density polyethylene (HDPE), high density and high molecular weight polyethylene (HDPE-HMW), high density and ultrahigh molecular weight polyethylene (HDPE-UHMW), medium density polyethylene (MDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), (VLDPE) and (ULDPE).

Polyolefins, i.e. the polymers of monoolefins exemplified in the preceding paragraph, preferably polyethylene and polypropylene, can be prepared by different, and especially by the following, methods:

a) radical polymerisation (normally under high pressure and at elevated temperature).

b) catalytic polymerisation using a catalyst that normally contains one or more than one metal of groups IVb, Vb, VIb or VIII of the Periodic Table. These metals usually have one or more than one ligand, typically oxides, halides, alcoholates, esters, ethers, amines, alkyls, alkenyls and/or aryls that may be either π- or σ-coordinated. These metal complexes may be in the free form or fixed on substrates, typically on activated magnesium chloride, titanium(lll) chloride, alumina or silicon oxide. These catalysts may be soluble or insoluble in the polymerisation medium. The catalysts can be used by themselves in the polymerisation or further activators may be used, typically metal alkyls, metal hydrides, metal alkyl halides, metal alkyl oxides or metal alkyloxanes, said metals being elements of groups Ia, Na and/or Ilia of the Periodic Table. The activators may be modified conveniently with further ester, ether, amine or silyl ether groups. These catalyst systems are usually termed Phillips, Standard Oil Indiana, Ziegler (-Natta), TNZ (DuPont), metallocene or single site catalysts (SSC).

2. Mixtures of the polymers mentioned under 1 ), for example mixtures of polypropylene with polyisobutylene, polypropylene with polyethylene (for example PP/HDPE, PP/LDPE) and mixtures of different types of polyethylene (for example LDPE/HDPE).

3. Copolymers of monoolefins and diolefins with each other or with other vinyl monomers, for example ethylene/propylene copolymers, linear low density polyethylene (LLDPE) and mixtures thereof with low density polyethylene (LDPE), propylene/but-1-ene copolymers, propylene/isobutylene copolymers, ethylene/but-1-ene copolymers, ethylene/hexene copolymers, ethylene/methylpentene copolymers, ethylene/heptene copolymers, ethylene/octene copolymers, propylene/butadiene copolymers, isobutylene/isoprene copolymers, ethy- lene/alkyl acrylate copolymers, ethylene/alkyl methacrylate copolymers, ethylene/vinyl acetate copolymers and their copolymers with carbon monoxide or ethylene/acrylic acid copolymers and their salts (ionomers) as well as terpolymers of ethylene with propylene and a diene such as hexadiene, dicyclopentadiene or ethylidene-norbornene; and mixtures of such copolymers with one another and with polymers mentioned in 1 ) above, for example polypropylene/ethylene-propylene copolymers, LDPE/ethylene-vinyl acetate copolymers (EVA), LDPE/ethylene-acrylic acid copolymers (EAA), LLDPE/EVA, LLDPE/EAA and alternating or random polyalkylene/carbon monoxide copolymers and mixtures thereof with other polymers, for example polyamides. 4. Hydrocarbon resins (for example C₅-C₉) including hydrogenated modifications thereof (e.g. tackifiers) and mixtures of polyalkylenes and starch.

5. Polystyrene, poly(p-methylstyrene), poly(α-methylstyrene).

6. Copolymers of styrene or α-methylstyrene with dienes or acrylic derivatives, for example styrene/butadiene, styrene/acrylonitrile, styrene/alkyl methacrylate, styrene/butadiene/alkyl acrylate, styrene/butadiene/alkyl methacrylate, styrene/maleic anhydride, styrene/acryloni- trile/methyl acrylate; mixtures of high impact strength of styrene copolymers and another polymer, for example a polyacrylate, a diene polymer or an ethylene/propylene/diene terpo- lymer; and block copolymers of styrene such as styrene/butadiene/styrene, styrene/iso- prene/styrene, styrene/ethylene/butylene/styrene or styrene/ethylene/propylene/ styrene.

7. Graft copolymers of styrene or α-methylstyrene, for example styrene on polybutadiene, styrene on polybutadiene-styrene or polybutadiene-acrylonitrile copolymers; styrene and acrylonitrile (or methacrylonitrile) on polybutadiene; styrene, acrylonitrile and methyl methacrylate on polybutadiene; styrene and maleic anhydride on polybutadiene; styrene, acrylonitrile and maleic anhydride or maleimide on polybutadiene; styrene and maleimide on polybutadiene; styrene and alkyl acrylates or methacrylates on polybutadiene; styrene and acrylonitrile on ethylene/propylene/diene terpolymers; styrene and acrylonitrile on polyalkyl acrylates or polyalkyl methacrylates, styrene and acrylonitrile on acrylate/butadiene copolymers, as well as mixtures thereof with the copolymers listed under 6), for example the copolymer mixtures known as ABS, MBS, ASA or AES polymers.

8. Halogen-containing polymers such as polychloroprene, chlorinated rubbers, chlorinated and brominated copolymer of isobutylene-isoprene (halobutyl rubber), chlorinated or sulfo- chlorinated polyethylene, copolymers of ethylene and chlorinated ethylene, epichlorohydrin homo- and copolymers, especially polymers of halogen-containing vinyl compounds, for example polyvinyl chloride, polyvinylidene chloride, polyvinyl fluoride, polyvinylidene fluoride, as well as copolymers thereof such as vinyl chloride/vinylidene chloride, vinyl chloride/vinyl acetate or vinylidene chloride/vinyl acetate copolymers. 9. Polymers derived from α,β-unsatu rated acids and derivatives thereof such as polyacry- lates and polymethacrylates; polymethyl methacrylates, polyacrylamides and polyacryloni- triles, impact-modified with butyl acrylate.

10. Copolymers of the monomers mentioned under 9) with each other or with other unsaturated monomers, for example acrylonitrile/ butadiene copolymers, acrylonitrile/alkyl acrylate copolymers, acrylonitrile/alkoxyalkyl acrylate or acrylonitrile/vinyl halide copolymers or acrylonitrile/ alkyl methacrylate/butadiene terpolymers.

1 1. Polymers derived from unsaturated alcohols and amines or the acyl derivatives or ace- tals thereof, for example polyvinyl alcohol, polyvinyl acetate, polyvinyl stearate, polyvinyl benzoate, polyvinyl maleate, polyvinyl butyral, polyallyl phthalate or polyallyl melamine; as well as their copolymers with olefins mentioned in 1 ) above.

12. Homopolymers and copolymers of cyclic ethers such as polyalkylene glycols, polyethylene oxide, polypropylene oxide or copolymers thereof with bisglycidyl ethers.

13. Polyacetals such as polyoxymethylene and those polyoxymethylenes which contain ethylene oxide as a comonomer; polyacetals modified with thermoplastic polyurethanes, acrylates or MBS.

14. Polyphenylene oxides and sulfides, and mixtures of polyphenylene oxides with styrene polymers or polyamides.

15. Polyurethanes derived from hydroxyl-terminated polyethers, polyesters or polybutadi- enes on the one hand and aliphatic or aromatic polyisocyanates on the other, as well as precursors thereof.

16. Polyamides and copolyamides derived from diamines and dicarboxylic acids and/or from aminocarboxylic acids or the corresponding lactams, for example polyamide 4, polyamide 6, polyamide 6/6, 6/10, 6/9, 6/12, 4/6, 12/12, polyamide 11 , polyamide 12, aromatic polyamides starting from m-xylene diamine and adipic acid; polyamides prepared from hexamethylenediamine and isophthalic or/and terephthalic acid and with or without an elastomer as modifier, for example poly-2,4,4,-trimethylhexamethylene terephthalamide or poly- m-phenylene isophthalamide; and also block copolymers of the aforementioned polyamides with polyolefins, olefin copolymers, ionomers or chemically bonded or grafted elastomers; or with polyethers, e.g. with polyethylene glycol, polypropylene glycol or polytetramethylene glycol; as well as polyamides or copolyamides modified with EPDM or ABS; and polyamides condensed during processing (RIM polyamide systems).

17. Polyureas, polyimides, polyamide-imides, polyetherimids, polyesterimids, polyhydantoins and polybenzimidazoles.

18. Polyesters derived from dicarboxylic acids and diols and/or from hydroxycarboxylic acids or the corresponding lactones, for example polyethylene terephthalate, polybutylene tereph- thalate, poly-1 ,4-dimethylolcyclohexane terephthalate, polyalkylene naphthalate (PAN) and polyhydroxybenzoates, as well as block copolyether esters derived from hydroxyl-terminated polyethers; and also polyesters modified with polycarbonates or MBS.

19. Polycarbonates and polyester carbonates.

20. Polysulfones, polyether sulfones and polyether ketones.

21. Crosslinked polymers derived from aldehydes on the one hand and phenols, ureas and melamines on the other hand, such as phenol/formaldehyde resins, urea/formaldehyde resins and melamine/formaldehyde resins.

22. Drying and non-drying alkyd resins.

23. Unsaturated polyester resins derived from copolyesters of saturated and unsaturated dicarboxylic acids with polyhydric alcohols and vinyl compounds as crosslinking agents, and also halogen-containing modifications thereof of low flammability.

24. Crosslinkable acrylic resins derived from substituted acrylates, for example epoxy acry- lates, urethane acrylates or polyester acrylates.

25. Alkyd resins, polyester resins and acrylate resins crosslinked with melamine resins, urea resins, isocyanates, isocyanurates, polyisocyanates or epoxy resins. 26. Crosslinked epoxy resins derived from aliphatic, cycloaliphatic, heterocyclic or aromatic glycidyl compounds, e.g. products of diglycidyl ethers of bisphenol A and bisphenol F, which are crosslinked with customary hardeners such as anhydrides or amines, with or without accelerators.

27. Natural polymers such as cellulose, rubber, gelatin and chemically modified homologous derivatives thereof, for example cellulose acetates, cellulose propionates and cellulose butyrates, or the cellulose ethers such as methyl cellulose; as well as rosins and their derivatives.

28. Blends of the aforementioned polymers (polyblends), for example PP/EPDM, PoIy- amide/EPDM or ABS, PVC/EVA, PVC/ABS, PVC/MBS, PC/ABS, PBTP/ABS, PC/ASA, PC/PBT, PVC/CPE, PVC/acrylates, POM/thermoplastic PUR, PC/thermoplastic PUR, POM/acrylate, POM/MBS, PPO/HIPS, PPO/PA 6.6 and copolymers, PA/HDPE, PA/PP, PA/PPO, PBT/PC/ABS or PBT/PET/PC.

29. Naturally occurring and synthetic organic materials which are pure monomeric compounds or mixtures of such compounds, for example mineral oils, animal and vegetable fats, oil and waxes, or oils, fats and waxes based on synthetic esters (e.g. phthalates, adipates, phosphates or trimellitates) and also mixtures of synthetic esters with mineral oils in any weight ratios, typically those used as spinning compositions, as well as aqueous emulsions of such materials.

30. Aqueous emulsions of natural or synthetic rubber, e.g. natural latex or latices of carbo- xylated styrene/butadiene copolymers.

Preferred olefinic polymers as main constituent of the particle core are those listed in the above sections 1 to 3, 5 to 7 and 9 to 11.

Any additives customary in the plastics industry, such as plasticisers, fillers or stabilisers, can be added to the polymer, in customary amounts; examples are listed e.g. in US-6184375 in the passage from column 17, line 57, to column 25, line 35, the contents of which is hereby incorporated by reference. A number of well suitable core materials are commercially available in the form of a latex, e.g. poly(styrene-butadiene) latex.

A class of particles of special interest contains a plasticizer, especially in the particle core; the plasticizer may be incorporated into the particle core by addition to the latex or by addition to the monomers before or during polymerization. Preferred particles are of uniform size (i.e. narrowly dispersed) and contain a very low residual content of solvent and/or monomer.

Uses

The particles of the invention are useful for the preparation of conductive structures such as layers, electronic devices such as OLEDs. These may be used as conductor material, conductor- or semiconductor-precursor, particles in capacitor applications, electrophoretic (dye) particles, IR absorbers e.g. in optical or acustic filters, electronic devices or light managing systems. For example, the present particles may be contained or form the main constituent of the hole injection layer in an OLED device. A further important application is the replacement of ITO, which is widely used mainly as an electrode material at present. Further electric or electronic devices, where the present particles may be used, thus include integrated circuits, displays, RFID tags, electro- or photoluminescent devices, backlights of a display, photovoltaic or sensor devices such as solar cells, charge injection layer, planarising layers, antistatics, conductive substrate or patterns, photoconductors, or electrophotographic applications or recording materials.

In an important application, the present particles are used for the formation of conducting or semiconducting layers. For this, particles as described above are applied to the substrate in a conventional manner, e.g. by application of the dry particles or by a coating or printing technique using the particles dispersed in a suitable solvent (e.g. water, alcohol or mixtures thereof) and drying. The conductive or semiconductive layer is then conveniently obtained by application of heat, e.g. to a temperature above the glass transition temperature of the synthetic organic polymer of the core particle.

Typical temperatures for conversion into a layer are in the range 80-250⁰C, e.g. 80-200⁰C. In case that the particle is applied by a printing process with application of (unidirectional) pressure (e.g. in xerographic printing/laser printing, or a transfer printing or compression bonding process as of US-7105462 or US-7176052), the combination of pressure and temperature may be used to transform the particles into the desired layer, which may result in more homogenous layers obtained at lower conversion temperatures. The invention thus includes electronic devices or optical or acustical filters comprising one or more types of particles as described above and/or a conductive or semiconductive layer obtained by conversion of the particles as described above.

The present particles may also be used as such in inks (i.e. as a pigment) or conductive inks or electrophoretic dye/pigment applications. In another embodiment, the present particles may be coated with a conductive metal such as silver, copper and/or gold and useed the composite particles thus obtained for conductive inks. In another application, silver or copper particles may be coated with the present layered polymer particles as a conductive and corrosion protective layer; this form of composite particle may also be used in conducting inks.

Some of the uses are explained in more detail in the below examples.

The following test methods and examples are for illustrative purposes only and are not to be construed to limit the instant invention in any manner whatsoever. Room temperature (R. T.) depicts a temperature in the range 20-25⁰C; over night denotes a time period in the range

12-16 hours. Percentages and ratios in the examples and elsewhere are by weight unless otherwise indicated.

Abbreviations used in the examples or elsewhere:

AIBN Azobisisobutyronitrile

DLS Dynamic light scattering

OLED Organic Light Emitting Diode

SDS sodiumdodecylsulfat

GPC gel permeation chromatography

THF tetrahydrofuran

PS polystyrene

SSEE styrene sulfonate ethyl ester

PSS polystyrenesulfonate

PEGMA poly (ethylene glycol) methacrylate methyl ether PPy polypyrrole

DVB divinyl benzene

PDI polydispersivity

TEM transmission electron microscopy pbw parts by weight

TOSOH stands for the supplier Tosoh Corp., Tokyo (JP)

ITO indium doped tin oxide

FTO fluorine doped tin oxide

UF ultrafiltration.

Preparation of Particles of the Invention

Example 1 : Slightly crosslinked polystyrene core; sodiumbenzene sulfonate corona

Latex in water

In a 1 L round bottom flask with mechanical stirring, 7.84 g (75.3 mmol) styrene (Fluka purum), 160 mg (0.77 mmol) 4-vinylbenzoic acid sodium salt (Fluka techn.), 0.20 g (1.5 mmol) divinylbenzene (Fluka techn.), 2.5 g sodiumdodecylsulfat (SDS, Fluka techn.) and 250 ml water are introduced and purged with nitrogen during 15 min. 1.75 g 1-pentanol (Fluka purum) is added and the whole mixture homogenized under N₂ with 300 rpm during 1 h. The homogeneous emulsion is heated with an oil bath to 90⁰C and 0.20 g potassiumperoxodisulfate (KPS, Fluka microselect) dissoved in 10 ml water is added with a syringe through a septum. Polymerization is done at 90⁰C for 6 h. After cooling to RT. the dispersion is ultrafiltrated with a cellulose membrane (Amicon® cell, diameter 76 mm, cut-off: 100O00 Da) until no more SDS (=surfactant) is detectable in the permeate (total permeate quantity: 1.6 L).

Analytics: Solid content of dispersion (graphimetric analysis after water evaporation): 3.03%. Dynamic light scattering (DLS): Average diameter (z-average): 12.8 nm. Example 2: Polystyrene core; Slightly crosslinked sodiumbenzene sulfonate corona

i in 4 h)

slightly (2%) crosslinked corona

DVB consisting of poly(SSEE-co-DVB)

PS latex in water _{1 Q g} O 2 g (=2%)

4 36 g PS (50 g latex) (47 2 mmol) (1 54 mmol) NaOH (2 26 g, 56 6 mmol) 15 h, 90°C

SSEE is added in 4 h parallel to the initiator

slightly (2%) crosslinked corona consisting of poly(SSS-co-DVB)

a) Core : In a 1 L round bottom flask with mechanical stirring, 5 g sodiumdodecylsulfat (SDS,

Fluka techn.) and 500 ml water are introduced and purged with nitrogen during 15 min. The mixture is stirred with 300 rpm heated with an oil bath to 50-55⁰C and 0.25 g potassiumperoxodisulfate (KPS, Fluka microselect) dissoved in 6 ml water is added under

N₂. 50 g (480.1 mmol) styrene (Fluka purum) is continuously added with a pump during 8 h.

After 3 h another portion of 0.25 g potassiumperoxodisulfate (KPS, Fluka microselect) dissoved in 6 ml water is added. After the addition of all styrene, reaction is continued at

50⁰C for 14 h. 567.9 g Latex with a solid content of 8.72 % is obtained.

Analytics:

DLS (after diluting with water to 1.5 %): Average diameter (z-average): 39.7 nm.

GPC (THF, PS standard): M_n=202000, M_w=615000, PDI=3.05.

b) Corona: In a 350 ml round bottom flask with mechanical stirring, 50 g of above emulsion (4.36 g solid material) is diluted with 120 ml water and purged with nitrogen during 1 h. The mixture is stirred with 300 rpm heated with an oil bath to 70°C and 10 g (47.2 mmol) styrene- 4-sulfonic acid ethyl ester (TOSOH techn.) mixed with 0.20 g (1.54 mmol) divinylbenzene (Fluka techn.) and 0.20 g potassiumperoxodisulfate (KPS, Fluka microselect) dissoved in 10 ml water is continuously added with a pump during 4 h. After the addition of all monomer and initiator, the reaction is continued at 70⁰C for 2 h (=postreaction). The ester is than hydrolysed by addition of 2.26 g (56.6 mmol) NaOH and stirring the mixture at 90°C for 2 h. Work-up: 5 g NaCI is dissolved in 600 ml MeOH and above reaction mixture added and stirred at R. T. for 10 min, followed by centrifugation (3000 rpm) for 10 min. The supernatant is discarded and the rest again added to a solution of 5 g NaCI in 600 ml MeOH, stirring and centrifugation as described above. This procedure is repeated 2 more times and than the precipitate re-dispesed in 440 ml water. The dispersion is then ultrafiltrated in a Amicon cell with a cellulose membrane (diameter 76 mm, cut-off: 100O00 Da) until no more SDS

(=surfactant) is detectable in the permeate (total permeate quantity: 750 ml).

Analytics:

The dispersion is freeze-dried and the solid content determined: 2.56%. It is easily re- dispersible in water afterwards.

Transmission electron microscopy (TEM): Average diameter d=28-39 nm.

Example 3: Synthesis of conductive (polypyrrol) shell, Core/shell Nanoparticles.

Polypyrrol (PPy) coating

slight

shell Q consisting of poly(SSS-co-DVB)

0.39 g (5.9 mmol) ^{1 0}O⁺⁵⁰ ^ H₂O Emulsion in water (=28% of core)

Purification by UF;

1.41 g (45 g emulsion) of AM-3445/1 lyophilization containing 23.6 mmol -SQNa

45 g of the core shell particle dispersion of Ex. 2 (1.41 g solid material) is diluted with 100 ml water in a 350 ml round bottom flask with mechanical stirring and degazed by purging with Ar for 1 h. 0.39 g (5.9 mmol) pyrrol (Fluka purum) is added and the mixture stirred with 300 rpm. 3.67 g (13.57 mmol) iron(lll)chloride-hexahydrate (Fluka puriss p. a.) dissoved in 50 ml water and purged with Ar is continuously added with a pump during 30 min. Thereafter, the reaction mixture is kept under Ar and stirring for another 30 min. at R.T. Note: The reaction mixture gets black upon addition of the iron salt i.e. formation of polypyrrol on the surface of the Nanoparticles.

Work-up: Homogenation with ultrasound followed by ultrafiltration in an Amicon® cell with a cellulose membrane (diameter 76 mm, cut-off: 100O00 Da) until a total permeate quantity of 300 ml). Analytics: The dispersion is freeze-dried and the solid content determined: 0.85%. The freeze-dried material is easily re-dispersed in water.

Elemental analysis; calc. (found): C 62.9 (57.0), H 4.93 (5.20), N 4.57 (4.65), S 8.59 (6.09). Transmission electron microscopy (TEM): Average diameter d=30-40 nm.

Example 4: Crosslinked polystyrene core/ crosslinked sodiumbenzene sulfonate corona.

g

first shell attached to (highly) crosslinked core consisting of poly(S-co-DVB)

In a 1 L round bottom flask with mechanical stirring, 6.0 g (57.6 mmol) styrene (Fluka purum), 2.0 g (15.4 mmol) divinylbenzene (Fluka techn.), 1.0 g sodiumdodecylsulfat (SDS, Fluka techn.) and 200 ml water are introduced, degazed and purged with nitrogen during 30 min. The mixture is homogeneous by stirring during 1 h and the emulsion heated with an oil bath to 70⁰C. 80 mg potassiumperoxodisulfate (KPS, Fluka microselect) dissoved in 5 ml water is added with a syringe through a septum. After prepolymerization during 30 min. at 70⁰C, 2.73 g (13.2 mmol) 4-vinylbenzoic acid sodium salt (Fluka techn.) dissolved in 15 ml water is added with a syringe through a septum, followed by a second portion of 40 mg potassiumperoxodisulfate (KPS, Fluka microselect) dissoved in 5 ml water. Polymerization with good stirring (300 rpm) for 15 min. at 70°C. Additional 18 g (87.3 mmol) 4-vinylbenzoic acid sodium salt (Fluka techn.) dissolved in 100 ml water is continuously added with a pump during 4 h. Thereafter, a third portion of 80 mg potassiumperoxodisulfate (KPS, Fluka microselect) dissoved in 5 ml water is added and the polymerization continued at 70⁰C for 16 h. After cooling to RT. the dispersion is ultrafiltrated in a Amicon® cell with a cellulose membrane (diameter 76 mm, cut-off: 300O00 Da) until a total permeate quantity of 3 L. Analytics:

The dispersion is freeze-dried and the solid content determined: 6.2%. It is easily re- dispersible in water.

Elemental analysis; calc. (found): C 60.3 (51.4), H 4.72 (5.51 ), S 10.85 (9.30).

Transmission electron microscopy (TEM): Average diameter d=18-28 nm.

Example 5: Synthesis of conductive core/shell nanoparticles. l (PPy) 'PPSS--DDVVBB

in water

22.74 g of the core shell particle dispersion of Ex. 4 (1.41 g solid material) is diluted with 100 ml water in a 350 ml round bottom flask with mechanical stirring and degazed by purging with

Ar for 1 h. 0.39 g (5.9 mmol) pyrrol (Fluka purum) is added and the mixture stirred with 300 rpm. 3.67 g (13.57 mmol) iron(lll)chloride-hexahydrate (Fluka puriss p. a.) dissoved in 50 ml water and purged with Ar is continuously added with a pump during 30 min. Thereafter, the reaction mixture is kept under Ar and stirring for another 30 min. at RT. Note: The reaction mixture gets black upon addition of the iron salt i.e. formation of polypyrrol on the surface of the Nanoparticles.

Work-up: Homogenation with ultrasound followed by ultrafiltration with a Jumbosep (PAL) filter device (membrane cut-off: 100O00 Da) in the centrifuge (2x 120 min. with 3000 rpm) with intermediate redispersion with Ultra-Turrax and ultrasound bath. Analytics:

The dispersion is freeze-dried and the solid content determined: 0.40%. It is easily re- dispersible in water afterwards.

Elemental analysis; calc. (found): C 63.1 (55.0), H 4.70 (5.47), N 4.53 (4.25), S 8.57 (7.04).

Transmission electron microscopy (TEM): Average diameter d=34 nm. Example 6: polystyrene (PS) core nanoparticles

In a 50OmL round bottom flask with a magnetic stirrer, 3.0 g sodium dodecyl sulfate (SDS, Fluka 99%) is dissolved in 300 ml. water. The transparent solution is heated with an oil bath to 50 ⁰C and purged with argon for one hour. 150 mg (0.55mmol) potassium persulfate in 1OmL water (KPS, Fluka 99%) are introduced. 10 mins after the addition of KPS solution, 30 g (288mmol) styrene (Fluka 99%) is added within 10 hours. 3 hours after the introduction of KPS, another 150mg KPS in 1OmL water is added with a syringe through a septum. The polymerization is lasted for another 3 hours after the complete addition of styrene. The resulting suspension can be used for the shell coating without purification.

Characterization:

Solid content of dispersion (graphimetric analysis): 9.8%

Scanning electron microscopy (SEM): 23.6 nm (number average diameter)

Dynamic light scattering (DLS): Rh = 20.5 nm (hydrodynamic radius)

Example 7: polystyrene-core polystyrene sulfonate shell (PS-PSS) nanoparticles

In a 1 L round bottom flask with a magnetic stirrer, 50 mL of the suspension obtained in example 6 (solid content 4.9 g) and 40OmL water are introduced. The suspension is heated to 70 ⁰C with oil bath and purged for one hour with argon. 100 mg KPS in 10mL water are introduced, and then a mixture of 10 g styrene sulfonate ethyl ester (SSEE, TOSOH, 91 %) and 100 mg divinyl benzene (DVB, Fluka, 80%) is added dropwise within 4 hours.

The polymerization is lasted for another 6 hours after the complete addition of the SSEE and

DVB mixture.

Hydrolysis of the PS/PSSEE core/shell nanoparticles by refluxing the nanoparticle / KOH / water suspension for 12 hours results in PS-PSS core shell nanoparticles. Complete hydrolysis is proved by solid state proton NMR.

4 cycles of precipitation from methanol and redispersion in water are used for the purification of the hydrolysed PS-PSS particles.

Characterization:

DLS: Rh = 57 nm (PS-PSSEE core shell particles) Rh = 330 nm (PS-PSS core shell particles) Example 8: PS-PSS-PPy nanoparticles

In 500 ml. round bottom flask, 20 mL of PS-PSS suspension (as obtained in example 7; solid content 700 mg) is diluted with 30OmL water and purged with argon for one hour. 10 mins after the addition of 170 mg pyrrole (Py, 2.5 mmol, Fluka 97%), 986 mg iron(lll) chloride (6.1 mmol, Fluka 97%) in 20 mL water is introduced dropwise within 2 hours. The reaction is lasted for another half an hour after the completion of the addition of ferric chloride. 4 cycles of precipitation from methanol and redispersion in water are used for the purification of PS-PSS-PPy nanoparticles.

Characterization:

DLS: Rh = 83 nm

TEM: mean diameter 52 nm, standard deviation 8 nm.

Example 9: Transmittance of thin films consisting of PS-PSS-PPy nanoparticles

PS-PSS-PPy nanoparticles are prepared as in example 8, except that the ratio PPy/(PS+PSS+PPy) is 16% (w/w).

A thin film with thickness of 87 nm is prepared by spincoating on a microscope slide, and the transmittance is measured with a Lambda UVA/IS/NIR- & UVA/IS Spectrometer (Perkin- Elmer). A transmittance above 82% is determined throughout the visible region (see Fig. 1 ).

Example 10: Redispersibility

The redispersibility examination of the particles after freeze-drying is carried out with dynamic light scattering (DLS; light scattering line with an ALV 5000 correlator [ALV, Langen, DE], an ALV-SP81 goniometer, an avalanche photodiode and a krypton ion laser (647.1 nm)) by comparing the size and size distribution of corresponding suspensions before and after freeze-drying. The experiment is based on particles of example 8. After freeze-drying of the suspension for four days, the material is redispersed in water by ultrasound. The particle size and size distribution is measured by DLS and compared with the one before freeze-drying. Figure 2 demonstrates that the particle size and size distribution remain the same in suspensions before and after freeze-drying for four days, which means that the redispersibility of PS-PSS-PPy nanopaticles is excellent. Similar results are obtained with any of the particles obtained in examples 17c, 18b, and 31.

Example 11 : Conductivity

Conductivity measurement is based on the four point-probe method as shown in Figure 3. Provided that (i) the thickness d of the specimen is much smaller than the distances x1 ,2,3 between the electrodes, (ii) the electrodes have an equispaced distance (x1 = x2 = x3), (iii) the specimen is placed on a non-conducting surface, (iv) the contact-diameter of the electrodes is small compared to the distance between the electrodes, and (v) the distance between the electrodes and the specimen-boundary is large compared to the distance between the electrodes, the intrinsic conductivity of the material can be calculated from the voltage and currant detected using the following equation (p_v = intrinsic resistivity, which is the reciprocal conductivity):

The specimen is prepared by pressing the dry powder of the material obtained in example 8 into a pellet with thickness of 0.679 mm. The conductivity measured is 3.8x10-2 S/cm.

Example 12: Evolution of conductivity behaviour with temperature and time

A special set-up is designed to monitor the evolution of the conductivity (σ) of the PPy composite pellet with temperature and time. Figure 4 shows photographs of the set-up. With this set-up, it t is possible to measure the conductivity at different temperatures (20°C-250°C) and different environments such as air, nitrogen, or argon.

PPy nanoparticles with the same composite as those of example 8 but prepared at different batches are used for the experiments. Figure 5 a) shows the resistivity of the PPy composite pellet decreases when temperature is increased from 25°C to 200⁰C. In the other words, the conductivity increases with the temperature. Shown in Figure 5 b) is the aging behaviour of the PPy composite pellet at 100⁰C in air. According to H. Muenstedt et al., a master curve can be drawn based on this graph. As such, aging behavior can be deduced at different temperature.

Example 13: Roughness

The colloidal films of PS-PSS-PPY particles are prepared by spin-coating using the spin coater of Headway Research. Inc.. The particle used is the one mentioned in example 9. The concentration is 2 % (w/w). The spin speed is adjusted to obtain a desired film thickness, which is measured by a TENCOR^® P-10 surface profiler. The surface quality of these colloidal films is checked by tapping mode atomic force microscopy (AFM), Dimension 3100 close loop (Digital instrument Veeco metrology group). Both height and phase images are obtained during the scanning of samples. In general, the height image reflects the topographic change across the sample surface while the phase image reflects the stiffness variation of the materials.

The mean roughness Ra represents the arithmetic average of the deviation from the center plane:

Z - Z cp

R = -^

N

Here, Zcp is the Z value of the center plane.

Shown in Figure 6 is the representative PPy composite film with thickness of 60nm, which is prepared at spincoating speed of 1500 rpm. According the above equation, the average roughness is 9nm.

Example 14: Film formation of PPy composite nanoparticles

In order to examine the film formation of PPy composite films, films prepared with the material from example 8 by spincoating (200⁰C, vacuum, 10 min). SEM images before and after heating are compared: Demonstrated in Figure 7 (left) is the SEM image of the PPy film before annealing, where the individual nanoparticle morphology is still retained. Shown in Figure 7 (right) is the SEM image of the same PPy films after annealed, where the boundary of the particles is not as obvious as the one before annealing and a continuous film formed. Example 15: Adhesion of the PS-PSS-PPy film to the substrates

Adhesion of the PPy film to the substrates (here glass and FTO covered glass are tested) is based on an adhesive-tape-test method as schematically described in Figure 8. Material as obtained in example 9 is used for the film formation by spincoating nanoparticles onto a microscope slide. The formed film is placed in a vacuum oven at 150⁰C for 5 mins to remove the water. And an adhesive tape is then placed above the PPy composite film followed by placing the sample in a vacuum oven for another 5min so that the adhesive tape has a good contact with the PPy film. SEM is used to check what is left after slowly lifting the adhesive tape from the PPy composite film as shown in Figure 8 (the lower row). Highlighted by the red circle in the left micrograph is the place where the adhesive tape previously stayed. The higher magnification micrograph at the right side exhibits that the PPy composite film is left intact while some materials are ripped off from the adhesive tape. This experiment demonstrates that the adhesion of the PPy composite film to the substrate is excellent.

Example 16: Preparation of light emitting device

Glass substrates with patterned ITO are cleaned with acetone, propanol and water in an ultrasonic bath. The dried substrates are treated with an oxygen plasma for 2 min. The compound of example 8 is spin-coated (5000 rpm) to obtain a film thickness of 70 nm. A reference sample is prepared in analogous manner (1500 rpm, 55 nm) but using PEDOT AL4083 (supplier: H. C. Starck) instead of the present compound.

The films are dried on a hot plate (10 min., 200 ⁰C, ambient atmosphere). Under nitrogen, a blue emitting polymer (compound of example 107 of WO 06/097419) is spin-coated on top with a layer thickness of 80 nm. The devices are finished by evaporation of a bilayer cathode consisting of 5 nm Ba and 70 nm Al. A schematic drawing of the OLED device is shown in Fig. 1 1. Device characterization is carried out under inert atmosphere. The results are shown in Fig. 12 (left: current density [A/cm²]; lower part/right: luminance [cd/m²]). Example 17

a]_polystyrene (PS) core nanoparticles

In a 500 mL round bottom flask with a mechanical stirrer, 2.0 g sodium dodecyl sulfate (SDS, Fluka 99%) is dissolved in 300 mL water. The transparent suspension is heated with an oil bath to 50 ⁰C and purged with argon for one hour. 100 mg (0.37 mmol) potassium persulfate (KPS, Fluka 99%) in 1 OmL water is introduced. 10 mins after the addition of KPS solution, 20 g (192mmol) styrene (Fluka 99%) is added while stirring (350 rpm) within 10 hours. 3 hours after the introduction of KPS, another 100 mg KPS in 1O mL water is added with a syringe through a septum. The polymerization is lasted for another 3 hours after the complete addition of styrene. The resulted suspension is filtrated through a glass fibre filter.. Characterization: Solid content of dispersion (graphimetric analysis): 5.4% Dynamic light scattering (DLS): Rh=21.4nm

b) polystyrene-core polystyrene sulfonate shell (PS-PSS) nanoparticles

In a 1 L round bottom flask with a mechanical stirrer, 148.15 g of the product of (a) (solid content 8 g) and 700 mL water are introduced. The suspension is heated to 50 ⁰C with oil bath and purged for one hour with argon. 80 mg Azobisisobutyronitrile (AIBN, Fluka 98%) are introduced, and then a mixture of 4 g styrene sulfonate ethyl ester (SSEE, TOSOH, 91%) and 120 mg divinyl benzene (DVB, Fluka, 80%) is added dropwise while stirring (450 rpm) within 4 hours. The polymerization is lasted for another 6 hours after the complete addition of the SSEE and DVB mixture. Hydrolysis of the PS/PSSEE core/shell nanoparticles by adding 3 g KOH and refluxing the suspension for 24 hours results in PS-PSS core shell nanoparticles. Complete hydrolysis is proved by solid state proton NMR and FTIR. The resulted suspension is purified by five cycles of precipitation and redispersion in methanol followed by three cycles of ultrafiltration. Characterization: DLS: Rh=142 nm

c) PS-PSS-PPy nanoparticles In 2 L round bottom flask, 150 g of PS-PSS suspension (as obtained according to (b); solid content 3 g) is diluted with 1.4 L water and purged with argon for one hour. 10 mins after the addition of 350 mg destilled pyrrole (Py, 5.21 mmol, Fluka 97%), 8.236 g iron(lll) p- toluenesulfonate hexahydrate (12.1 mmol, Aldrich tech.) in 20 ml. water is introduced dropwise within 3 hours. The reaction is lasted for another half an hour after the completion of the addition of iron(lll) p-toluenesulfonate hexahydrate.

3 cycles of precipitation from methanol and redispersion in water and 3 cycles of ultrafiltration are used for the purification of PS-PSS-PPy nanoaprticles.

Characterization:

DLS: Rh=81.2nm; TEM: mean diameter 51 nm, standard deviation 10 nm.

d) Conductivity of the PPy composite obtained in (c): pellet with four point method: 2.8^*10^"5 S/cm pellet with Dielectric spectroscopy: 8.4^*10^"5 S/cm thin film with four point method: 1.5^*10^"6 S/cm

e) Film properties of composite obtained in (c): roughness and transmittance

The colloidal films of PS-PSS-PPY particles are prepared by spin-coating using the spin coater of Headway Research. Inc.. The particle concentration is 2 % (w/w). The spin speed is adjusted to obtain a desired film thickness, which is measured by a TENCOR^® P-10 surface profiler. The surface quality of these colloidal films is checked by tapping mode atomic force microscopy (AFM), Dimension 3100 close loop (Digital instrument Veeco metrology group). The annealed PPy composite film of thickness of 152 nm is prepared at spincoating speed of 1500 rpm. Results: The mean average roughness is 5 nm.

f) Transmittance of the PPy composite film obtained in (e)

Transmittance is measured with a Lambda UV/VIS/NIR- & UV/VIS Spectrometer (Perkin- Elmer). Results: A transmittance above 88% is determined throughout the visible region, with maximum 92% at 550-570 nm. Example 18

a) polystyrene-core polystyrene sulfonate shell (PS-PSS) nanoparticles

In a 1 L round bottom flask with a mechanical stirrer, 129.63 g of the PS nanoparticle suspension obtained in section (a) of Example 17 (solid content 7 g) and 600 ml. water are introduced. The suspension is heated to 50 ⁰C with oil bath and purged for one hour with argon. 35 mg Azobisisobutyronitrile (AIBN, Fluka 98%) are introduced, and then a mixture of

1.75 g styrene sulfonate ethyl ester (SSEE, TOSOH, 91%) and 52,5 mg divinyl benzene

(DVB, Fluka, 80%) is added dropwise while stirring (450 rpm) within 4 hours. The polymerization is lasted for another 6 hours after the complete addition of the SSEE and DVB mixture.

Hydrolysis of the PS/PSSEE core/shell nanoparticles by adding 1.4 g KOH and refluxing the suspension for 24 hours results in PS-PSS core shell nanoparticles. Complete hydrolysis is proved by solid state proton NMR and FTIR.

The resulting suspension is purified by five cycles of precipitation and redispersion in methanol followed by three cycles of ultrafiltration.

Characterization:

DLS: Rh=120 nm

b) PS-PSS-PPy nanoaprticles

In 1 L round bottom flask, 42.70 g of the above PS-PSS suspension (solid content 1.2 g) is diluted with 600 ml. water and purged with argon for one hour. 10 mins after the addition of

150.3 mg destilled pyrrole (Py, 2.24 mmol, Fluka 97%), 5.181 g Baytron C-B 40 (H. C. Starck, contents 40.4% iron(lll) p-toluenesulfonate hexahydrate in 1-butanol) is introduced dropwise within 3 hours. The reaction is lasted for another half an hour after the completion of the addition of Baytron C-B 40.

3 cycles of precipitation from methanol and redispersion in water and 3 cycles of ultrafiltration are used for the purification of PS-PSS-PPy nanoaprticles.

Characterization: DLS: 78.9 nm

Conductivity: pellet with four point method: pellet with dielectric spectroscopy: Example 19

a) PS-PSS/PEGMA core shell

In a 250 mL round bottom flask with a magnetic stirrer, 2 g of the PS nanoparticle suspension obtained in section (a) of Example 17 (solid content) and 150 mL water are introduced. The suspension is heated to 60 ⁰C with oil bath and purged for one hour with argon. 20 mg Azobisisobutyronitrile (AIBN, Fluka 98%) are introduced, and then a mixture of 0.6 g styrene (Fluka 99%) and 0.4 g divinyl benzene (DVB, Fluka, 80%) is added dropwise while stirring (450 rpm) within 1.5 hours. The polymerization is lasted for another 1.5 hours before 3g sodium styrene sulfonate (NaSS, Fluka >90%) and 0.50 g poly (ethylene glycol) methacrylate methyl ether (50% in water, Aldrich, Mw: 2080) in 1O mL water are added within 1 hour. After that the reaction is continued for another 10 hours. Incorporation of NaSS and PEGMA are proved by FT-IR.

The resulted suspension is purified by five cycles of precipitation and redispersion in methanol saturated with sodium chloride followed by three cycles of ultrafiltration. Characterization: DLS: Rh=87 nm TEM: 67 nm

b) PS-PSS/PEGMA-PPy

In 100 mL round bottom flask, 5.128 g of PS-PSS/PEGMA suspension (as obtained in section (a), solid content 100 mg) is diluted with 80 mL water and purged with argon for one hour. 10 mins after the addition of 42.9 mg destilled pyrrole (Py, 0.639 mmol, Fluka 97%), 2.1 11 g Baytron C-B 40 (H. C. Starck, contents 40.4% iron(lll) p-toluenesulfonate hexahydrate (1.490 mmol) in 1-butanol) is introduced dropwise within 3 hours. The reaction is lasted for another half an hour after the completion of the addition of Baytron C-B 40. 3 cycles of precipitation from methanol and 3 cycles of ultrafiltration are used for the purification of PS-PSS/PEGMA-PPy nanoparticles. Characterization: DSL: 83.4 nm Conductivity, pellet with four point method: 0.1 1 S/cm Examples 20-22: Core/shell nanoparticles with softer core and softer shell

In order to make the core and the shell softer (for easier penetration of the core material and build-up of continuous PS-copolymer phases and PPy phases upon annealing), additional co-monomers in various amounts are used (see also Schemes 1-3):

Example 20 :

cT "o SDS / KPS

+ O O -KkKkW) / \ DSC: o- Q o' = PS-BA-ALMA) Tg=28°C

H₂O; N₂ 2 h, 70°C Emulsion

S BA ALMA d=22 nm (DLS) d=14 nm (TEM)

42 Wt. % 50 wt. % 8 Wt. %

CORE not crosslinked

W!Ϊh 35VΪS

PSS AS SECONE) SMEELl.

Scheme 1 : Synthesis of anionic core/shell NP's with a more flexible core and crosslinked first and second shells with 42% BA: Examples 20 and 21.

In a 1 L round bottom flask with mechanical stirring, 5.0 g sodiumdodecylsulfat (SDS, Fluka techn.) and 200 ml water are introduced, degazed and purged with nitrogen 3 times during 15 min. The mixture is heated with an oil bath to 55°C and stirred at 200 rpm and a first portion of 250 mg potassiumperoxodisulfate (KPS, Fluka microselect) dissoved in 6 ml water is added with a syringe through a septum. The monomers 21.0 g (201.6 mmol) styrene (Fluka purum), 25.0 g (195.1 mmol) n-butyl acrylat (Fluka purum) and 4.0 g (31.7 mmol) allylmethacrylat (Fluka purum) are mixed and added dropwise with a syringe and a pump during 8 h. After 3 h reaction time, another portion of 250 mg potassiumperoxodisulfate (KPS, Fluka microselect) dissoved in 6 ml water is added with a syringe through a septum. After the addition of all monomer, polymerization is continued for an additional 14 h at 55°C.

After cooling to R. T. , 576.6 g latex is obtained with a solid content of 7.3 %.

Analytics:

DSC: Tg=28°C

Dynamic light scattering (DLS): d (z-average)=22 nm.

Transmission electron microscopy (TEM): Average diameter d=14 nm.

Example 21 :

In a 1 L round bottom flask with mechanical stirring, 41.1 g of the dispersion according to example 17 is diluted with 200 ml water, degazed and purged with nitrogen 3 times during 15 min. 1.5 g (1 1.5 mmol) divinylbenzene (DVB, Fluka techn. Mixture of isomers) and 1.5 g n- butylacrylate (Fluka purum) is added foloowed by 40 mg potassiumperoxodisulfate (KPS,

Fluka microselect) dissoved in 3 ml water is added. The mixture is heated with an oil bath to

70⁰C and polymerized during 30 min. while stirring at 200 rpm. Than 80 mg potassiumperoxodisulfate (KPS, Fluka microselect) dissoved in 6 ml water is added and

20.61 g (90 mmol) p-styrene sodium sulfonate (Fluka tech. 90%) and 0.37 g (1.9 mmol) ethylene-glycol dimethacrylat (EDMA, Fluka purum) dissolved in 100 ml water (=monomer 1 ) and 13.34 g n-butyl acrylate mixed with 0.27 g EDMA (=monomer 2) are added simultaneously during 3.5 h at 70⁰C. After that another portion of 40 mg potassiumperoxodisulfate (KPS, Fluka microselect) dissoved in 3 ml water is added and the polymerization continued for another 16 h at 70⁰C. After cooling to R. T. the latex is ultrafiltrated in a Amicon® cell with a cellulose membrane (diameter 76 mm, cut-off: 300O00

Da) until a total permeate quantity of 3 L. 10 g of the dispersion is freeze-dried and the solid content determined: 6.73%. It is easily re-dispersible in water.

Analytics:

Elemental analysis: calc (found): C 58.35 (55.81 ) H 6.39 (6.71 ) S 7.40 (6.94) C/S 7.88

(8.04)

Transmission electron microscopy (TEM): Average diameter d=33 nm. Example 22:

Similar to the examples 20 and 21 , core shell nanoparticles with the core as in example 20 and different comonomers and different amounts of polystyrene-sulfonate in the second shell are made, see Schemes 2 and 3:

Tg=28°C

8 !5A

FIRS? SMELL

SO₃Na PSS AS SECOND SHELL

Scheme 2: Synthesis of anionic core/shell NP's with a more flexible core and crosslinked first shell with 100% polystyrene-sulfonate in the second shell: Example 22.

KPS

H₂O, N₂

Core 7 7 wt %

1 Shell 7 7 wt % 30 mm, 70°C

2 Shell 84 6 wt % DV 8 BA

0 0 ><»!ted jnd Witt: OVB

EDMA o % 0 4 Wt %

SECOND SHELL *ιih more BA as flexibilizei

Scheme 3: Synthesis of anionic core/shell NP's with a more flexible core and crosslinked first and second shell with a high butyl acrylate content (81 %): Example 23.

Examples 24-26: The anionic nanoparticles with softer cores and shells according to examples 21-23, displayed in Schemes 1-3, are coated with pyrrole shells of different thickness, according to Scheme 4. One example (Ex. 24) is given in detail.

λ=450 nm 6%)

13% '

PPy content 33% of total particle

S content 9 65% λ=450 nm 2% T=45 3%) 4 91% 5 51%

of total particle λ=450 nm 6% T=49 0%)

12% 2 24%

PPy content 12 2 % of total particle

S content 241% Note 0 001 % dispersion corresponds to a dry layer thickness of ca 100 nm d=28 nm (TEM) 97 nm (DLS)

Scheme 4: Synthesis of polypyrrole (PPy) shells with different thickness.

Example 24: Coating of the particles according to Ex 21 with polypyrrole

In a 350 ml round bottom flask with mechanical stirring, 20.0 g of the dispersion according to example 21 is diluted with 100 ml water, degazed and purged with argon 3 times during 45 min. 0.543 g (8.1 mmol) pyrrole (Fluka purum) is introduced and homogenized. 12.62 g

(18.63 mmol) iron(lll)tosylat-hydrate (Fe(tos)₃6 H₂O, Aldrich) dissolved in 40 ml water is added dropwise via a syringe and a pump during 30 min at R. T. After the addition of all iron

(lll)tosylate, the reaction mixture is stirred for another 30 min. The reaction mixture is ultrafiltrated in a Amicon® cell with a cellulose membrane (diameter 76 mm, cut-off: 300O00

Da) until a total permeate quantity of 3 L. 1 g of the dispersion is freeze-dried and the solid content determined: 0.62%. It is easily re-dispersible in water.

Analytics:

Elemental analysis: calc (found): N 6.00 (5.11 ) S 4.91 (5.51 ) Transmission electron microscopy (TEM): Average diameter d=41 nm.

Example 27: Here, the core/shell nanoparticles according to example 21 is coated with polyaniline (instead of polypyrrole):

In a 350 ml round bottom flask with mechanical stirring, 16.0 g of the dispersion according to example 21 is diluted with 100 ml water, degazed and purged with argon 3 times during 45 min. 0.46 ml (0.47 g, 5.0 mmol) aniline (Aldrich) is introduced, homogenized and cooled to

0⁰C with an ice bath. 1.03 g (4.51 mmol) ammonium-peroxo-disulfate (Merck) dissolved in 40 ml water is added dropwise via a syringe and a pump during 30 min at 0⁰C, whereby the reaction mixture becomes green (emerald color of polyaniline). After the addition of all

(NhU)₂S₂O₈, the reaction mixture is stirred for another 1 h at 0⁰C followed by 17 h at RT. The reaction mixture is ultrafiltrated in a Amicon® cell with a cellulose membrane (diameter 76 mm, cut-off: 300O00 Da) until a total permeate quantity of 1 L. 1 g of the dispersion is freeze- dried and the solid content determined: 0.74%. It is easily re-dispersible in water.

Analytics:

Elemental analysis: calc (found): N 3.49 (3.21 ) S 5.32 (5.99)

Transmission electron microscopy (TEM): Average diameter d=44 nm.

Example 28: Thermogravimetric Analysis (TGA; material as of example 8; 25-800⁰C; 107min; N₂) shows 8.6 % water loss between 40 and 150°C, and beginning decomposition above 420⁰C.

Example 29: DC conductivity at 293.15 K of composite pellets is detected by dielectric spectroscopy as described in example 17d. The particles used are obtained in analogy to those described in example 17c, but depositing various amounts of PPy shell material. The results show a strong increase of conductivity from particles containing less than 10 % b.w. of PPy (ca. 10^"8 S/cm) to those containing about 10 to about 25 % b.w. of PPy (10^"3 to 10^"1 S/cm; see Fig. 13).

Example 30: Polystyrene-core with first thin, highly cross-linked polystyrene/divinylbenzene shell and second, non-cross-linked poly(sodium styrene sulfonate) shell (PS-P(S/DVB)-PSS) In a 2 L round bottom flask with a mechanical stirrer, 307.22 g of the suspension of example

6 (solid content 16.59 g) and 1500 ml. water are introduced. The suspension is heated to 60

⁰C with an oil bath and purged for one hour with argon. 580 mg Azobisisobutyronitrile (AIBN,

Fluka 98%) are introduced, and after 10 min a mixture of 5.80 g styrene (Acros 99%) and

1 ,45 mg divinyl benzene (DVB, Fluka, 80%) is added dropwise while stirring (450 rpm) within one hour.

The polymerization is lasted for 70 min at 60 ⁰C after the complete addition of the styrene/DVB mixture.

A mixture of 5.32 g sodium styrene sulfonate (NaSS, Fluka 92%) and 1.09 g poly(ethylene glycol) methyl ether methacrylate (PEGMA, Aldrich, M_n = 2080 g/mol, 50 wt% solution in water) in 60 ml. water is added within one hour. The polymerization is lasted for another 12 hours at 60 ⁰C while stirring. The resulting suspension is purified by ion exchange (Amberjet

4200 Cl^") and three cycles of ultrafiltration, treated with unltrasound and filtrated first through a 0.8 μm and then through a 0.45 μm membrane.

Yield: 22.7 g (83.5 %)

Solid content of dispersion (graphimetric analysis): 2.65 %

C/H/S/Na analysis (calc. / found): C (83.13 % / 83.12 %)

H (7.32 % / 7.17 %)

S (2.74 % / 1.99 %)

Na (1.97 % / 1.28%) DLS: r_h = 37.4 nm

Example 31 : PS-P(S/DVB)-PSS-PPy nanoaprticles

In 2 L round bottom flask with a mechanical stirrer, 1 13.21 g suspension of example 30 (solid content 3 g) is diluted with 1.7 L water and purged with argon for one hour. 10 mins after the addition of 158 mg destilled pyrrole (Py, 2.36 mmol, Fluka 97%), 3.139 g iron(lll) p- toluenesulfonate (5.48 mmol, H. C. Starck) in 25 ml. water is introduced dropwise within 3 hours while stirring. The reaction is lasted for another half an hour after the completion of the addition of iron(lll) p-toluenesulfonate.

The resulting suspension is purified by ion exchange (Amberlite IR-120 H⁺), three cycles of ultrafiltration and passed through a 0.8 μm and a 0.45 μm filter.

AAS: 56.9 μg Fe/g

PPy-content by nitrogen analysis: 4.7 % DLS: r_h = 48 nm

Conductivity increases with the PPy amount

Brief description of Figures

Figure 1 : UVA/IS transmittance of PS-PSS-PPy thin film.

Figure 2: DLS results of the particle suspension of example 8 before and after Freeze-drying for 4 days. Figure 3: Schematic representation of four point-probe method as of example 11 , and the way to calculate the intrinsic resistivity, which is the reciprocal conductivity. Figure 4: Photographs of set-up used to monitor the evolution of conductivity with temperature and time. Figure 5: a) Evolution of resistivity of the PPy composite pellet with temperature in argon. b) Aging of conductivity behaviour of the PPy composite pellet in air. Figure 6: AFM images of the film of example 13, left height image and right phase image.

The spin speed is 1500 rpm and the film thickness is 60 nm. Ra = 9 nm. Figure 7: SEM images of a PPy composite film (example 14) before (left) and after (right) heating. Figure 8: Upcenter, the scheme of the adhesive tape test. Lower row, SEM images of the

PPy composite film after adhesive tape is slowly lifted away (example 15). Figure 9: Scheme of core/shell polypyrrole composite nanoparticle with a softer poiymes cϋϊe Jiϊd an aiuonic pclvelecϊrϋhte shell embedded with PP} Heie part of the sjiiomc jTolvtlectiohie αcN ?s tlic ccsnitenoss fla dse PPy, and the nest poht lee iraivte provides an

force to pi event COIIOKISI ήocαilanon sn "water or W ater organic mixture medium It is. the iest amcauc polveiectroh Te that render tedisperxibiktx of PP\" n?Jiopaiϊicie^ As inch ths ccmψ^-Λtt paiticlev piepared can be tsm_'-φcrted aud s

old a-s po^dei

Figure 10: Scheme of core/shell PPy composite nanoparticle with a softer polymer core and a polymer mixture corona containing a polyelectrolyte as counterion for the polypyrrole shell and further chain(s) providing (further) electrosteric or steric properties.

Figure 11 : Schematic drawing of OLED device of example 16.

Figure 12: Characteristics of device of example 16 (left: current density [A/cm²]; lower part/right: luminance [cd/m²]; horizontal axis: voltage).

Figure 13:Conductivity of composites containing various amounts of polypyrrole.

Claims

Claims

1. Layered particle comprising a thermoplastic or crosslinked, non-halogenated polymeric core, containing anionic functional groups on its surface, and an oxidatively polymerized shell, which particle is characterized in that it is easily redispersible in a polar solvent.

2. Layered particle comprising a thermoplastic or crosslinked, non-halogenated polymeric core, containing anionic functional groups on its surface, and an oxidatively polymerized shell, especially according to claim 1 , which particle contains sterically protruding neutral groups and/or an excess of anionic functional groups covalently bonded to its core surface.

3. Layered particle of claim 1 or 2, wherein the core consists essentially of a synthetic organic polymer, which is crystalline or amorphous at 20⁰C and has a glass transition temperature of 150⁰C or lower, preferably selected from olefinic polymers.

4. Layered particle according to any of claims 1 to 3, wherein the core consists essentially of polystyrene or polyacrylics; especially polystyrene.

5. Layered particle according to any of claims 1 to 4, wherein the anionic functional groups are selected from carboxylate and especially sulfonate and/or phosphonate groups, which are preferably present as polyanionic chains, such as obtainable by co-oligomerization or polymerization of the core particle with one or more suitable monomers

PG-Sp-Ra, wherein PG stands for a polymerizable group like a vinyl group;

Ra is an anionic functional group as mentioned above;

Sp is a direct bond or suitable organic spacer moiety comprising 1 to about 50 carbon atoms,

Sp being especially selected from alkylene, cycloalkylene and arylene groups and their combinations and such groups interrupted by oxygen or sulphur or nitrogen and/or substituted by O, S, which monomers are preferably selected from vinylbenzenesulfonic, C₂-

C₈alkenylsulfonic, (meth)acryloyloxy-C₂-C₈alkyl-sulfonic, (meth)acryloylamido-C₂-C₈alkyl- sulfonic, vinylbenzenephosphonic, C₂-C₈alkenylphosphonic, (meth)acryloyloxy-C₂-C₈alkyl- phosphonic, (meth)acryloylamido-C₂-C₈alkyl-phosphonic acids, esters and salts.

6. Layered particle according to any of claims 1 to 5, wherein the oxidatively polymerized shell is obtained by oxidative coupling of unsubstituted or substituted pyrrole, aniline or thiophene.

7. Layered particle according to any of claims 1 to 6, wherein the oxidatively polymerized shell consists essentially of polypyrrole.

8. Layered particle according to any of claims 1 to 7, wherein the anionic groups are located on oligomeric or polymeric hydrocarbon chains of 8-100 carbon atoms.

9. Process for the preparation of a layered particle according to any of claims 1 to 8, which process comprises polymerization of a suitable monomer, in the presence of a polar solvent and intermediate particles dispersed in said solvent, by addition of an oxidizing agent, characterized in that the intermediate particles comprise a thermoplastic or crosslinked polymeric core containing anionic functional groups covalently bonded to its surface.

10. Process of claim 9, wherein the intermediate particles have been prepared by emulsion polymerization of an ethylenically unsaturated monomer to form a core particle, where a suitable comonomer containing carboxylate or especially sulfonate or phosphonate groups, such as acids along with their esters and salts selected from vinylbenzenesulfonic, C₂- C₈alkenylsulfonic, (meth)acryloyloxy-C₂-C₈alkyl-sulfonic, (meth)acryloylamido-C₂-C₈alkyl- sulfonic, vinylbenzenephosphonic, C₂-C₈alkenylphosphonic, (meth)acryloyloxy-C₂-C₈alkyl- phosphonic, (meth)acryloylamido-C₂-C₈alkyl-phosphonic derivatives, is added during the polymerization step forming the core particle, or copolymerized with the core particle in a subsequent step, and where optionally, during formation of the core particle or during copolymerization of the core particle with the comonomers or both, a minor amount of crosslinking agent is present.

1 1. Process of claim 9 for the preparation of a layered particle comprising a soft core and a polypyrrole shell, characterized in that a core particle essentially consisting of a synthetic organic polymer, which is crystalline or amorphous at 20⁰C and has a glass transition temperature of 150⁰C or lower, especially selected from olefinic polymers such as polystyrene or polyacrylics, is subjected to the following steps subsequently: a) copolymerization with a suitable monomer containing functional groups SO₃H, SO₃M or SO₃Ri, wherein M stands for one equivalent of a metal cation and Ri stands for a C₁-C₂0 hydrocarbon residue such as Ci-C₈alkyl, especially with styrene sulfonic acid or a suitable salt or ester thereof,

b) optionally converting the sulfonic groups, especially SO₃H and SO₃Ri introduced in step (a), if present, into SO₃M, especially SO₃Na, and

c) polymerizing pyrrole on the surface of the particles.

12. Process of claim 11 , wherein i) steps (a), (b) and (c) are carried out in a dispersant selected from water and polar organic solvents and mixtures thereof; ii) the conversion of sulfonic acid or sulfonic ester groups of step (b), if any, is carried out by introduction of alkaline hydroxide such as NaOH; iii) the polymerization of step (c) is carried out by addition of [j \ and a suitable oxidant

N H such as an Fe(III) salt, FeCI₃, iron(lll) tosylate; iv) the dispersion obtained after step (c) is subjected to desalination (d), e.g. by ultrafiltration.

13. Particles or particle dispersion obtained in a process according to any of claims 9-12.

14. Process for the preparation of a conductive or semiconductive layer comprising heating of a layer comprising one or more types of particles as of any of claims 1 to 9 or claim 13, especially particles of claim 3, to a temperature above the glass transition temperature of the synthetic organic polymer of the core particle.

15. Electronic device or optical or acustical filter comprising one or more types of particles according to any of claims 1 to 9 or 13 and/or a conductive or semiconductive layer obtained by a process as of claim 14, especially electronic device selected from integrated circuits, displays, RFID tags, electro- or photoluminescent devices, backlights of a display, photovoltaic or sensor devices, solar cells.

16. Use of particles or a dispersion of particles according to any of claims 1 to 9 or 13 as a conductor material, conductor-precursor, electrophoretic (dye) particles, pigments, IR absorbers, especially in charge injection layers, planarising layers, antistatics, conductive substrates or patterns, photoconductors, electrophotographic applications, recording materials, and/or for the preparation of conductive structures, conductive inks, capacitors, optical or acustic filters, electronic devices, light managing systems.