COLLOIDAL COATING DISPERSION

Abstract

Disclosed are a colloidal coating dispersion containing electrochromic polymer particles, a method for manufacturing the colloidal coating dispersion, the use of the colloidal coating dispersion for depositing at least one electrochromic layer on a substrate, and an article including a layer deposited from the colloidal coating dispersion.

Claims

1-18. (canceled)

19. A colloidal coating dispersion comprising electrochromic polymer particles having an average particle size d.sub.50 in the range from 1 to 200 nm as solid phase and at least one organic solvent as liquid phase; wherein the solids content of the colloidal coating dispersion is from 0.1 to 20 wt.-% based on the total mass of the colloidal coating dispersion; the electrochromic polymer particles are derived from a water-insoluble monomer; and the colloidal coating solution contains a maximum of 5 wt.-% of stabilizers and dispersing agents.

20. The colloidal coating dispersion according to claim 19, wherein the average particle size d.sub.50 of the electrochromic polymer particles is in the range from 10 to 200 nm; and/or the solids content of the colloidal dispersion is from 0.5 to 10 wt.-%, based on the total mass of the colloidal coating dispersion.

21. The colloidal coating dispersion according to claim 19, wherein the water-insoluble monomer is selected from the group consisting of pyrrole and pyrrole derivatives, thiophene and thiophene derivatives, sidechain-modified alkylene-3,4-dioxythiophenes, obtained by subsequently performing the following steps: a) reacting a solution comprising a mixture of a compound having the general formula (I) and a compound having the general formula (II) in a molar ratio of (I):(II) which is equal to m:(100m) wherein m has a value from 60 to 99 ##STR00012## with a compound of the general formula (III) ##STR00013## wherein X is selected from the group consisting of Y, YC(O), OCN or YCH.sub.2C(O)O in which Y is selected from halides, mesylates, and triflates, R is a linear and/or branched alkylene chain with 1 to 16 carbon atoms, and A is a linear and/or branched alkyl chain with 1 to 16 carbon atoms or hydrogen; b) optionally further reacting the mixture of compounds derived from step a) by either b1) a vinyl copolymerisation or b2) a hydrosilylation of the vinyl moiety with a silane of the general formula HSiR.sub.u(R).sub.3-u, wherein: R is selected from the group consisting of linear or branched alkyl or alkenyl chains with 1 to 12 carbon atoms in the main chain, wherein the chains can be substituted with acryloxy-, methacryloxy-, succinyl-, amino-, hydroxyl-, mercapto-, and/or glycidyloxy groups and/or interrupted by O- and/or S-atoms and/or a NR group, R is selected from the group consisting of halogens, hydroxyl groups, alkoxy groups and/or acyl groups with 1 to 4 carbon atoms, and u=0, 1, 2, 3; and further b3) a thiol-ene addition to the vinyl moiety with a compound of the general formula HSRSiR.sub.u(R).sub.3-u, wherein R, R, R and u have the same meaning as indicated above; and c) chemical oxidative polymerisation of a solution of the compound and/or the compounds derived from step b); and/or the organic solvent is an alcohol.

22. The colloidal coating dispersion according to claim 21, wherein the sidechain-modified alkylene-3,4-dioxythiophene comprises the units according to the following general formulae (IV) and (V) ##STR00014## wherein Z is selected from the group consisting of the structural elements R, C(O)R, C(O)NHR, and CH.sub.2C(O)OR, wherein R is a linear and/or branched alkylene chain with 1 to 16 carbon atoms, D is selected from the group consisting of: H, SiR.sub.u(R).sub.3-u, and SRSiR.sub.u(R).sub.3-u, wherein R has the same meaning as indicated above, R is selected from the group consisting of linear or branched alkyl chains and linear or branched alkenyl chains, each with 1 to 12 carbon atoms in the main chain, wherein the chains are optionally substituted with acryloxy-, methacryloxy-, succinyl-, amino-, hydroxyl-, mercapto-, and/or glycidyloxy groups and/or interrupted by O- and/or S-atoms and/or a NR group, wherein R has the same meaning as indicated above, R is selected from the group consisting of halogens, hydroxyl groups, and alkoxy groups and acyl groups each with 1 to 4 carbon atoms, and u=0, 1, 2, 3; or alternatively represents a chemical bonding to corresponding positions D of neighbored monomers of the formulae (IV) and/or (V), and A is a linear and/or branched alkyl chain with 1 to 16 carbon atoms or hydrogen, and the compounds of the general formulae (IV) and (V) are comprised in a molar ratio of (IV):(V).sup.=m/(100m), wherein m has a value in the range from 1 to 99.

23. The colloidal coating dispersion according to claim 19, wherein the colloidal coating dispersion comprises additives selected from the group consisting of non-polymeric binder materials, surfactants, and polymeric binders.

24. The colloidal coating dispersion according to claim 19, wherein, after 12 months of storage, no agglomeration, precipitation, or phase separation occurs.

25. A method for manufacturing the colloidal coating dispersion according to claim 19, comprising the following steps: (i) providing at least one water-insoluble monomer; (ii) providing at least one organic solvent; (iii) dissolving the water-insoluble monomer from step (i) in the organic solvent from step (ii); (iv) adding at least one oxidizing agent before, during or after step (iii) to initiate polymerization of the water-insoluble monomer; (v) polymerizing the water-insoluble monomer; and (vi) removing the oxidizing agent added in step (iv) to stop the polymerization and obtain the colloidal coating dispersion.

26. The method according to claim 25, wherein the molar ratio between the at least one water-insoluble monomer provided in step (i) and the at least one organic solvent provided in step (ii) is from 1:25 to 1:510; and/or the molar ratio between the at least one oxidizing agent provided in step (iv) and the at least one water-insoluble monomer provided in step (i) is from 1:1.50 to 1:3.00; and/or step (v) is carried out for a period of time from 1 to 72 h.

27. The method according to claim 26, wherein, the water-insoluble monomer is selected from the group consisting of pyrrole and pyrrole derivatives, thiophene and thiophene derivatives, sidechain-modified alkylene-3,4-dioxythiophenes, and mixtures thereof; and/or the organic solvent is an alcohol, optionally in combination with one or more additional organic solvent(s); and/or the oxidizing agent is selected from the group consisting of iron(III)-salts.

28. The method according to claim 26, wherein the oxidizing agent iron(III)-salt is selected from the group consisting of iron(III)-chloride, iron-(III)-sulphate, iron-(III)-perchlorate, iron(III) butylnaphthaenesulphonate, iron-(III)-alkylsulphonates, iron-(III)-carboxylate, iron(III) camphorsulphonate, iron-(III)-dodecylsulphonate, iron-(III)-salts of aromatic sulphonic acids, hydrogen peroxide, dichromates, peroxydisulphates, perchlorates, persulphates, perborates, permanganates, and mixtures thereof.

29. The method according to claim 25, wherein step (vi) is carried out by diluting the mixture with an organic solvent, and stirring the resulting mixture, adding water to obtain an aqueous phase and an organic phase, and separating the aqueous phase containing the oxidizing agent.

30. The method according to claim 29, wherein after step (vi), at least one organic solvent is added to adjust the solids content in the range from 0.1 to 20 wt.-% based on the total weight of the colloidal coating dispersion.

31. The method according to claim 25, wherein: water is added before or during step (iii); the organic solvent provided in step (ii) is acetonitrile, and/or steps (ii) to (v) are conducted in a temperature range from 5 to 15 C., and/or step (v) is conducted over a period of time from 1.5 to 4.5 hours; or the organic solvent provided in step (ii) is n-butanol, and/or steps (ii) to (v) are conducted in a temperature range from 15 to 25 C., and/or step (v) is conducted over a period of time from 60 to 80 hours.

32. The method according to claim 25, wherein additives are added before, after or during step (v), and the additives are selected from the group consisting of non-polymeric binder materials, surfactants, polymeric binders, inorganic-organic hybrid polymers and mixtures thereof.

33. A coated substrate deposited with a coating produced from the colloidal coating solution according to claim 19.

34. The coated substrate according to claim 33, wherein the deposition is conducted by spin coating, slot-die coating or a printing process.

35. The coated substrate according to claim 33, wherein the coated substrate is selected from the group consisting of transparent conducting plastic films coated with a transparent conducting oxide selected from the group consisting of tin-doped indium oxide, fluorine-doped tin oxide, aluminium-doped zinc oxide, aluminium-doped zirconium oxide, antimony-doped tin oxide, antimony/tin-doped zinc oxide, indium/tin-doped zinc oxide, and/or mixtures thereof, glass coated with a transparent conducting oxide selected from the group consisting of tin-doped indium oxide, fluorine-doped tin oxide, aluminium-doped zinc oxide, aluminium-doped zirconium oxide, antimony-doped tin oxide, antimony/tin-doped zinc oxide, indium/tin-doped zinc oxide, and/or mixtures thereof, metal coated with a transparent conducting oxide selected from the group consisting of tin-doped indium oxide, fluorine-doped tin oxide, aluminium-doped zinc oxide, aluminium-doped zirconium oxide, antimony-doped tin oxide, antimony/tin-doped zinc oxide, indium/tin-doped zinc oxide, and/or mixtures thereof, textiles and fabrics comprising metal wires, or a conducting oxide selected from the group consisting of tin-doped indium oxide, fluorine-doped tin oxide, aluminium-doped zinc oxide, aluminium-doped zirconium oxide, antimony-doped tin oxide, antimony/tin-doped zinc oxide, indium/tin-doped zinc oxide, and/or mixtures thereof, plastic film, glass, metal, and fabrics coated with an intrinsically conducting polymer, preferably PEDOT:PSS and combinations thereof; plastic film, glass, metal, and fabrics coated with a transparent conducting oxide selected from the group consisting of tin-doped indium oxide, fluorine-doped tin oxide, aluminium-doped zinc oxide, aluminium-doped zirconium oxide, antimony-doped tin oxide, antimony/tin-doped zinc oxide, indium/tin-doped zinc oxide, and/or mixtures thereof and an intrinsically conducting polymer, preferably PEDOT:PSS and combinations thereof; plastic film, glass, metal, and fabrics coated with a transparent layer stack comprising insulator/metal/insulator, semi-conductor/metal/insulator or semi-conductor/metal/semi-conductor layers or multiples thereof, an optionally over- or under-coated metal mesh or grid, an optionally over- or undercoated metal or carbon nanowire deposit, carbon nanotubes, graphene and mixtures thereof.

36. An article comprising at least one layer deposited from the colloidal coating solution according to claim 19.

37. The article according to claim 36, wherein the deposited layer consists of at least one electrochromic polymer; and/or the layer adhesion determined according to DIN EN ISO 2409 is rated with GT0; and/or the visual transmission hub determined according to DIN EN 410 is in the range from 55 to 60%.

Description

DESCRIPTION OF THE FIGURES

[0102] FIG. 1 shows the results of (in-situ) spectro-electrochemical measurements of the layer obtained from a dispersion according to Working Example 1.

[0103] FIG. 2 shows the results of (in-situ) spectro-electrochemical measurements of the layer obtained from a dispersion according to Working Example 2.

[0104] FIG. 3 shows UV-Vis-NIR spectra measured during the polymerization according to Working Example 2.

[0105] FIG. 4 shows scanning electron microscopy image (field emission scanning electron microscope Ultra 55 from Carls Zeiss NTS GmbH) of electrochromic polymer layers. FIG. 4 (magnification: 3.00 KX) and 5 (magnification: 7.50 KX) shows layers obtained by in-situ polymerization of the electrochromic polymer on the surface of a substrate, respectively. An alveolar surface structure is observed.

[0106] FIG. 5 shows another scanning electron microscopy image (field emission scanning electron microscope Ultra 55 from Carls Zeiss NTS GmbH) of electrochromic polymer layers.

[0107] FIG. 6 (magnification: 10.00 KX) shows a layer deposited from a colloidal coating dispersion according to the present invention. As can be gathered from this figure the surface is homogenous and smooth.

[0108] The subject according to the invention is intended to be explained in more detail with reference to the subsequent examples without wishing to restrict said subject to the specific embodiments shown here.

Measuring Methods

[0109] Within the scope of this application, the following measuring methods have been used.

UV-Vis-NIR-Spectroscopy

[0110] The UV-Vis-NIR spectra were measured on a digital CCD Avantes Ava-Spec-2048 Standard Fiber Optic Spectrometer of the company Avantes. The light source used was a deuterium-halogen lamp combination from Avantes (wave length from 200 nm to 2500 nm). The optical contribution of the substrate was taken into account by a reference measurement. The measurements were carried out at room temperature. The sample was arranged so that first the electrochromic layer and subsequently the substrate were irradiated.

(In-Situ) Spectroelectrochemical Measurements

[0111] The in-situ spectro-electrochemical measurements were also carried out with the AvaSpec-2048 Standard Fiber Optic Spectrometer from Avantes. For this purpose, the sample of the electrochromic layer to be analyzed was first arranged on a PET-ITO film (working electrode) and then installed in a special glass cuvette made for the Fraunhofer Institute for Silicate Research ISC. The area of the sample was 1.73.0 cm.sup.2. For better contacting, the conductive side of the sample was glued to the uncoated edge with a copper tape commercially available from 3M. The counterelectrode used consists of platinum and the electrolyte used was 1 M lithium perchlorate in propylene carbonate. The required switching voltage was generated with a Voltcraft PS 1152A laboratory power supply.

REM-EDX

[0112] The polymer layers were examined in terms of topology and composition using a field emission scanning electron microscope Ultra 55 from the company Carl Zeiss NTS GmbH under high vacuum. Acceleration voltage, working distance and magnification are each given together with the corresponding images. The samples to be examined were sputtered with platinum on the sputtering unit MED 010 from Oerlikon Balzers Coating AG.

Layer Adhesion

[0113] The adhesion quality of the electrochromic polymer layers on the PET-ITO substrate was determined by means of the cross-cut and tape test in accordance with DIN EN ISO 2409. For this purpose, 6 horizontal and 6 vertical sections were cut into the layer at a distance of 1 mm using a cutter knife and a template. Subsequently, an adhesive tape was applied to the cutting grid and pulled off after a waiting time of 1 minute.

Particle Size

[0114] To measure the particle size distribution of the dispersions, the method of dynamic light scattering was used. The measurement was carried out on the Zetasizer Nano ZS of Malvern Instruments GmbH using a red helium-neon laser emitting at a wavelength of 633 nm. Ethanol was used as the dispersing medium.

2 Starting Materials

[0115] The materials used for manufacturing the colloidal coating dispersion according to the invention are compiled in table 1.

TABLE-US-00003 TABLE 1 Components Manufacturer n-butanol Sigma Aldrich iron(III)-tosylate Heraeus n-heptanol Sigma Aldrich hydrochloric acid Merck

[0116] Furthermore, the mixture EDOT-C6 as shown below has been used as monomer.

##STR00011##

[0117] The monomer mixture EDOT-C6 (ratio of EDOT:ProDOT isomer=99:1) has been prepared according to the conditions and methods disclosed in WO 2008/064878 A1.

3 EXAMPLES

Example 1 (Inventive)

[0118] Example 1 was carried out in a round flask equipped with a magnetic stirring bar. First, the solvent n-butanol (5 mol) was added to the round flask and then the monomer mixture EDOT-C6 (1 mol) was added at 25 C. under stirring to obtain a yellowish, but transparent solution. Subsequently, the solution has been stirred for further 10 minutes at 300 rpm. Then the oxidizing agent iron(III)-tosylate (1.75 mol solved in 20 mol n-BuOH) was added under stirring. The resulting yellow-orange mixture has been stirred and polymerized at 25 C. for 72 hours. Afterwards, the polymerization was stopped by solvent extraction. For that purpose the reaction mixture was added into n-heptanol (6.5 mol) and the solvent extraction was conducted in a separating funnel using distilled water acidified with 1 molar hydrochloric acid (pH 2-3, 5 times the volume of the organic phase) as aqueous phase. For entirely removing the oxidizing agent from the organic phase the solvent extraction process was repeated three times with the same amount of the acidified aqueous phase. The obtained deep blue dispersion (organic phase) was filtered via a syringe filter (5 m). Finally, the solid content of the dispersion was adjusted to 7.5 wt.-% by addition of n-butanol (30 mol).

[0119] The dispersion produced this way shows high stability of several months (at least 24 months). Therefore, no stability-improving surfactants or other additives need to be added. A binder material may be added if the subsequent coating process requires it. Likewise, the solids content, initially at 7.5%, can be reduced by adding more n-butanol. This resultsin contrast to the effect of a binder additivein a reduction of the viscosity of the coating solution. Even without a binder, the inventive coating exhibits excellent adhesion to electronically conductive plastic substrates (e.g. PET-ITO) and a temperature stability that generally exceeds that of the substrates. FIG. 1 shows the results of the (in situ) spectro-electrochemical measurements of the layers resulting from the colloidal coating dispersion according to Example 1. These measurements represent the most important properties of an electrochromic layer. The visual transmission hub for the obtained layer is 31% and has been calculated according to DIN EN 410.

Example 2 (Inventive)

[0120] Example 2 was conducted in a double-walled reaction vessel equipped with a thermometer and a mechanical stirrer (crescent-shaped). The oxidizing agent iron(III)-tosylate (2.25 mol) was added to a laboratory bottle, acetonitrile (255 mol) and distilled water (13.7 mol) were added as solvents. Under stirring by using a magnetic stirrer the oxidizing agent was solved in the solvents at 25 C. EDOT-C6 (1 mol) was added under stirring (300 rpm) at 25 C. In the meantime the double-walled reaction vessel was cooled to 8 C. by using a cryostat. The resulting solution containing the solvents, the oxidizing agent and the monomer was added to the cooled doubled-walled reaction vessel and the polymerization was conducted for 3 hours at that temperature. Afterwards, the polymerization was stopped by solvent extraction. For that purpose the reaction mixture was added into n-heptanol (15 mol) and the solvent extraction was conducted in a separating funnel using distilled water, acidified with 1 molar hydrochloric acid (pH 2-3, 5 times the volume of the organic phase) as aqueous phase. For entirely removing the oxidizing agent from the organic phase the solvent extraction process was repeated three times with the same amount of the acidified aqueous phase. The obtained deep blue dispersion (organic phase) was filtered via a syringe filter (5 ipm). Finally, the solid content of the dispersion was adjusted to 7.5 wt. % by addition of n-butanol (30 mol).

[0121] The dispersion prepared this way shows high storage stability. FIG. 2 shows the results of the (in situ) spectro-electrochemical measurements of the layers resulting from the colloidal coating dispersion according to Example 2. These measurements represent the most important properties of an electrochromic layer. The visual transmission hub for the obtained layer is 57% and has been calculated according to DIN EN 410.

[0122] FIG. 3 shows the development of the UV-Vis spectra as a function of the polymerization time. The spectra were recorded on a highly diluted colloidal coating dispersion. Surprisingly, no longer polymer chains are achieved by a longer polymerization time (bathochromic shift of the absorption band). On the contrary, an optimum results at a polymerization time of 3 h.

Example 3

[0123] Example 3 was conducted in a jacketed reaction vessel equipped with a thermometer and a magnetic stirrer. The oxidizing agent iron(III)-tosylate (2.25 mol) was added to a laboratory bottle, acetonitrile (255 mol) and distilled water (13.5 mol) were added as solvents. Under stirring by using a magnetic stirrer the oxidizing agent was solved in the solvents at 25 C. EDOT-MeOH (1 mol) was added under stirring (300 rpm) at 25 C. In the meantime the jacketed reaction vessel was cooled to 8 C. by using a cryostat. The resulting solution containing the solvents, the oxidizing agent and the monomer was added to the cooled jacketed reaction vessel and the polymerization was conducted for 3 hours at that temperature. Afterwards, the polymerization was stopped by solvent extraction. For that purpose the reaction mixture was added into n-heptanol (12 mol) and the solvent extraction was conducted in a separating funnel using distilled water, acidified with 1 molar hydrochloric acid (pH 2-3, 5 times the volume of the organic phase) as aqueous phase. For entirely removing the oxidizing agent from the organic phase the solvent extraction process was repeated three times with the same amount of the acidified aqueous phase. The obtained deep blue dispersion (organic phase) was filtered via a syringe filter (5 m). Finally, the solid content of the dispersion was adjusted to 7.5 wt. % by addition of n-butanol (36 mol). FIG. 4 shows the results of the (in situ) spectro-electrochemical measurements of the colloidal coating dispersion according to Example 3. These measurements represent the most important properties of an electrochromic ink.

Example 4

[0124] Example 4 was conducted in a jacketed reaction vessel equipped with a thermometer and a magnetic stirrer. The oxidizing agent iron(III)-tosylate (2.25 mol) was added to a laboratory bottle, acetonitrile (255 mol) and distilled water (13.5 mol) were added as solvents. Under stirring by using a magnetic stirrer the oxidizing agent was solved in the solvents at 25 C. EDOT-MeOH (1 mol) was added under stirring (300 rpm) at 25 C. In the meantime the jacketed reaction vessel was cooled to 8 C. by using a cryostat. The resulting solution containing the solvents, the oxidizing agent and the monomer was added to the cooled jacketed reaction vessel and the polymerization was conducted for 3 hours at that temperature. Afterwards, the polymerization was stopped by solvent extraction. For that purpose the reaction mixture was added into n-heptanol (12 mol) and the solvent extraction was conducted in a separating funnel using distilled water, acidified with 1 molar hydrochloric acid (pH 2-3, 5 times the volume of the organic phase) as aqueous phase. For entirely removing the oxidizing agent from the organic phase the solvent extraction process was repeated three times with the same amount of the acidified aqueous phase. The obtained deep blue dispersion (organic phase) was filtered via a syringe filter (5 m). Finally, the solid content of the dispersion was adjusted to 7.5 wt. % by addition of n-butanol (36 mol). FIG. 5 shows the results of the (in situ) spectro-electrochemical measurements of the colloidal coating dispersion according to Example 3. These measurements represent the most important properties of an electrochromic ink.

Example 5

[0125] Example 4 was conducted in a laboratory bottle equipped with a magnetic stirrer. The oxidizing agent iron(III)-tosylate (2.25 mol) was added to the laboratory bottle, acetonitrile (255 mol) and distilled water (13.5 mol) were added as solvents. Under stirring by using a magnetic stirrer the oxidizing agent was solved in the solvents at 25 C. EDOT-NTCI-EtHEx (1 mol) was added under stirring (300 rpm) at 25 C. The polymerization was conducted for 10 min at room temperature (25 C.). Afterwards, the polymerization was stopped by solvent extraction. For that purpose the reaction mixture was added into n-heptanol (12 mol) and the solvent extraction was conducted in a separating funnel using distilled water, acidified with 1 molar hydrochloric acid (pH 2-3, 5 times the volume of the organic phase) as aqueous phase. For entirely removing the oxidizing agent from the organic phase the solvent extraction process was repeated three times with the same amount of the acidified aqueous phase. The obtained deep blue dispersion (organic phase) was filtered via a syringe filter (5 m). Finally, the solid content of the dispersion was adjusted to 7.5 wt. % by addition of acetonitrile (200 mol). FIG. 6 shows the results of the (in situ) spectro-electrochemical measurements of the colloidal coating dispersion according to Example 5. These measurements represent the most important properties of an electrochromic ink.

Example 6

[0126] Example 6 was conducted in a jacketed reaction vessel equipped with a thermometer and a magnetic stirrer. The oxidizing agent iron(III)-tosylate (2.25 mol) was added to a laboratory bottle, acetonitrile (255 mol) and distilled water (13.7 mol) were added as solvents. Under stirring by using a magnetic stirrer the oxidizing agent was solved in the solvents at 25 C. EDOT-C6 (1 mol) was added under stirring (300 rpm) at 25 C. In the meantime the jacketed reaction vessel was cooled to 8 C. by using a cryostat. The resulting solution containing the solvents, the oxidizing agent and the monomer was added to the cooled doubled-walled reaction vessel and the polymerization was conducted for 4 hours at that temperature. Afterwards, the polymerization was stopped by solvent extraction. For that purpose the reaction mixture was added into a n-heptanol/toluol (10 mol/10 mol) mixture and the solvent extraction was conducted in a separating funnel using distilled water, acidified with 1 molar hydrochloric acid (pH 2-3, 5 times the volume of the organic phase) as aqueous phase. For entirely removing the oxidizing agent from the organic phase the solvent extraction process was repeated three times with the same amount of the acidified aqueous phase. The obtained deep blue dispersion (organic phase) was filtered via a syringe filter (5 m). FIG. 7 shows the results of the (in situ) spectro-electrochemical measurements of the colloidal coating dispersion according to Example 6. These measurements represent the most important properties of an electrochromic ink.

Example 7

[0127] Example 4 was conducted in a jacketed reaction vessel equipped with a thermometer and a magnetic stirrer. The oxidizing agent iron(III)-tosylate (2.25 mol) was added to a laboratory bottle, acetonitrile (255 mol) and distilled water (13.5 mol) were added as solvents. Under stirring by using a magnetic stirrer the oxidizing agent was solved in the solvents at 25 C. Pyrrole (1 mol) was added under stirring (300 rpm) at 25 C. In the meantime the jacketed reaction vessel was cooled to 8 C. by using a cryostat. The resulting solution containing the solvents, the oxidizing agent and the monomer was added to the cooled jacketed reaction vessel and the polymerization was conducted for 4 hours at that temperature. Afterwards, the polymerization was stopped by solvent extraction. For that purpose the reaction mixture was added into n-heptanol (12 mol) and the solvent extraction was conducted in a separating funnel using distilled water, acidified with 1 molar hydrochloric acid (pH 2-3, 5 times the volume of the organic phase) as aqueous phase. For entirely removing the oxidizing agent from the organic phase the solvent extraction process was repeated three times with the same amount of the acidified aqueous phase. The obtained deep blue dispersion (organic phase) was filtered via a syringe filter (5 m). Finally, the solid content of the dispersion was adjusted to 7.5 wt. % by addition of n-butanol (36 mol). FIG. 5 shows the results of the (in situ) spectro-electrochemical measurements of the colloidal coating dispersion according to Example 3. These measurements represent the most important properties of an electrochromic ink.

Deposition of Electrochromic Layers

[0128] Electrochromic layers were deposited from the dispersion obtained from Examples 1 and 2 within the scope of pilot plant trials on a fully automatic roll-to-roll coating plant. The substratea polyethylene terephthalate coated with tin-doped indium oxidewas subjected to corona pretreatment (1.00 kW). By using a slot-die with a 50 m shim, wet films of various thicknesses were applied to the substrate. For this purpose, the slot-die is filled with an Oerlikon Barmag gear pump (type: 1-012-8055). The wet film thickness can be controlled via the pump frequency and the web speed. The pump frequency is in the range of 5 to 60 Hz and the web speed in the range between 0.1 and 1.0 m/min. After application of the coating dispersion the wet film is dried in four oven modules (2100 C., 2120 C.), wherein the drying temperature can be varied between 80 and 140 C. A wet film thickness of 18 m has been obtained by applying a web speed of 0.5 m/min and a pump frequency of 18 Hz.

[0129] As can be gathered from the table below, the optical properties and the layer adhesion for a substrate coated from a colloidal dispersion according to the present invention and coated by in-situ polymerization are almost the same. However, the colloidal coating dispersion according to the present invention allows not only to deposit layers by well-scalable and straightforward standard processes, but additionally allows to obtain smooth and homogenous layers that will not produce substantial haze (diffuse light scattering). Further the present invention is to avoid the in-situ-polymerization processes for depositing layers of pure electrochromic polymers on a substrate leading to a technically less demanding, less solvent consuming and more economic coating process.

TABLE-US-00004 Comparative Example 1.sup.a Example 2 Transmission hub 61 66 (625 nm) [%] Layer adhesion GT0 GT0 .sup.aComparative Example 1 corresponds to sample TCM431 in table 6 of EP 2 570 846 A1