WO2002029773A2

WO2002029773A2 - Electronic display device and coating therefor

Info

Publication number: WO2002029773A2
Application number: PCT/US2001/029816
Authority: WO
Inventors: Ranganathan Shashidhar; Yi Jun Miao; Nikolay Nikolov
Original assignee: The United States Of America, As Represented By The Secretary Of The Navy
Priority date: 2000-09-29
Filing date: 2001-09-26
Publication date: 2002-04-11
Also published as: WO2002029773A3; AU2002212976A1

Abstract

A coating composition and an electronic display device characterized by having the composition disposed on a pair of spaced substrates. The composition is processable, has surface resistance of about 700 Φ/< or less and optical transmittance of about 70 % or higher. The composition includes the following components given in weight percent: electrically conducting polymer 0.1-5; dispersant for the polymer 0.1-5; polyhydroxy compound 0.1-20; ionic dopant 0.1-40; water to 100; the polyhydroxy compound has formula; CH2OH-(-CH OH-)n-CH2OH where n is up to 20.

Description

Electronic Display Device and Coating Therefor

Background of the Invention

Field of the Invention:

This invention pertains to the field of electronic display-related devices, such as liquid crystal displays (LCDs) and organic light emitting displays (OLEDs), and to highly transparent and electrically conducting processable coating compositions containing a polymer.

Description of Related Art:

Most of the current liquid crystal displays use glass coated with indium tin oxide as the conducting substrates. These conducting substrates serve as electrodes to apply a voltage to the liquid crystal. Fabrication of indium tin oxide coating on glass is carried out at an elevated temperature of about 250°C in order to have acceptably short deposition times.

This has been problematic for incorporating other components, like color filters, into the display devices. More importantly, the fact that indium tin oxide deposition is a high temperature process makes it unsuitable for plastic displays. This is because plastics do not stand temperatures greater than about 150°C. Also, indium tin oxide (ITO) deposition is not a web-compatible process and hence not suitable for large scale manufacturing of plastic liquid crystal displays.

Although electronically conducting polymers have been known since 1973, the possibility of using conducting polymer coated plastic for liquid crystal displays was not considered until recently. This was essentially because none of the available conducting polymers, like polyaniline polypyrrole or polythiophene, showed the necessary combination of properties suitable for liquid crystal displays. Recently, it was demonstrated that thin polypyrrole films, processed using an in-situ deposition process, have surface resistance and optical transparency, the two important parameters that are most relevant to liquid crystal displays, that are reasonably adequate for liquid crystal displays. However, two major problems still remained that needed to be solved before conducting polymers could be seriously considered for liquid crystal displays and other display applications. The first problem concerns the competition between the surface resistance and optical transparency. For liquid crystal displays, as well as for other display-related applications, like organic light emitting displays, the surface resistance has to be as low as possible whereas the optical transparency has to be as high as possible. All attempts to optimize these two properties essentially gave the same trends for any variation associated with a processing parameter - a reduction in the surface resistance was always accompanied by a concomitant reduction of the optical transparency. In other words, reduction of surface resistance always led to a serious compromise on the optical transparency.

The second problem, which has also been common to all conducting polymers mentioned above, has been the difficulty in processing. For instance, polyrrole is not soluble in most of the solvents and hence is not a processable conducting polymer. Attempts have been made to improve solubility by attaching surfactant groups or alkyl chains chemically to the pyrrole structure. However, such attachments also led to a drastic reduction in conductivity and increase in surface resistance. Thus, conducting polymers that can be easily processed and whose films have low surface resistance and high optical transparency, have remained elusive. Objects and Brief Summary of the Invention

An object of the invention is an electronic display-related device characterized by a transparent and conducting processable film.

Another object of the invention is a coating on a substrate that is fabricated at a temperature that is suitable for plastic displays. Another object of this invention is a polymer coating for electronic display devices that is modestly priced relative to the prior art coating compositions for similar purposes.

Another object of this invention is an optically transparent and electrically conducting polymer coating composition for electronic display devices wherein surface resistance is substantially independent of optical transparency. These and other objects of this invention are achieved by an electronic display device that is characterized by an optically transparent and electrically conducting thin polymer processable film coating composition disposed on a substrate that can be fabricated at temperatures that are not degrading to plastics.

Brief Description of the Drawings Fig. 1 is a schematic illustration of an electronic liquid crystal display device showing the polymer coating composition disposed on a substrate.

Fig. 2 is a schematic illustration of an electronic light emitting display device showing the polymer coating disposed on a substrate.

Fig. 3 is a graph of optical transmittance and surface resistance plotted against glycerol concentration of a polymer composition spin-coated on a plastic substrate at 500 rpm. Fig. 4 is a graph showing variation of optical transmittance and surface resistance with coating compositions containing sulfosalicylic acid (SSA); glycerol; mixtures of sulfosalicylic acid (SSA) and glycerol; and mixtures of glycerol, sulfosalicylic acid (SSA), and sodium salt of anthraquinone-2-sulfonic acid (AQSA).

Detailed Description of the Invention This invention pertains to an electronic display device and to a coating composition therefor. The electronic display device is characterized by an optically transparent and electrically conducting processable coating composition disposed on a substrate. The coating composition includes a processable and dispersible polymer, a dispersant for the polymer, a non-ionic polyhydroxy compound, and an ionic dopant. The coating composition is processable in that it is soluble and/or dispersible, has high optical transparency above 70% and low surface resistance of less than about 700 Ω/D.

Figs. 1 and 2 schematically illustrate typical electromc display devices. Fig. 1 shows a liquid crystal display device which modulates light upon application of voltage, and Fig. 2 shows a light emitting diode display device which produces light on application of voltage. Other electronic display devices are also contemplated herein characterized by the optically transparent and electrically conducting processable coating compositions disposed on a suitable substrate.

The Fig. 1 sketch shows principal components of typical electronic liquid crystal display device which modulates light directed thereat on application of voltage. The device 100 of Fig. 1 includes a pair of spaced optically transparent substrates 102, 104 with substrate 102 being the lower and substrate 104 being the upper substrate. The substrates are typically planar although curved configurations can be used. Material of the substrates is optically transparent and is typically glass but it can be anything else such as plastic, metal, ceramic, and the like, provided it can withstand fabrication temperature without disintegrating in any substantial respect. Disposed on the lower transparent substrate 102 is the optically transparent and electrically conducting processable coating film 106 which is more fully defined below. Similar or identical is the upper film 108 which is disposed on the upper transparent substrate 104. Films 106 and 108 are typically thin, varying in thickness from about 5 nm to about 5 μm, although the thickness can be anything desired. Thin films are prefeπ-ed. Disposed on lower coating 106 is the lower aligning surface 110 and a similar or another upper aligning or even a non-aligning surface 112 is disposed against the upper coating 108. Between the two 110 and 112 surfaces is disposed liquid crystal material 114.

The schematic of the liquid crystal display device 100 shown in Fig. 1 is in the form of a stack and modulates light 116 directed at the stack from below on application of voltage between the transparent and conduction coatings 106, 108, as shown generally by the circuit designated 118.

Fig. 2 is a schematic illustration of another electronic display device, in this case a light emitting display device 200. The electronic display device of Fig. 2 includes a pair of spaced substrates, i.e., lower substrate 202 and upper substrate 204. Again, the substrates can be of any material desired, although they are typically of glass or plastic. If plastic substrates are used, care must be taken not to expose them to high temperatures at which they may degrade. Adjacent to and in contact with and between the substrates are lower transparent and conducing coating 206 and the upper like coating 208. These coatings 206,

208 are similar or identical to the coatings 106, 108 in the device a Fig. 1. Between the transparent and conducing processable coatings 206, 208 are anode 210 disposed a adjacent and in contact with the lower coating 206 and cathode 212, spaced above the anode, disposed adjacent and in contact with the upper coating 208. Between the anode and the cathode is the light emitting diode material 214.

The schematic of the electronic light emitting display device 200 shown in Fig. 2 is in the form of a stack and produces light on application of voltage between the transparent and conducting coatings 206, 208.

The coatings or coating compositions or thin films or layers 106, 108 in the representation of electronic liquid crystal display device of Fig. 1 and coatings 206, 208 in the electronic light emitting display device of Fig. 2 are optically transparent, electrically conducting, and processable. The coatings have optical transmission to visible light having wavelength of about 400-700 nm of greater than about 70%, preferable excess of about 80%.

Surface resistance of the coatings is less than about 800 Ω/D, preferably less than about 500 Ω/D. The polymer in the coating is soluble or dispersible in water or another solvent that might be used. By adding the dopant to the polymer, surface conductivity of the coating is enhanced approximately 10 fold, from about 6500 Ω/D to below about 800 Ω/D.

The coating composition includes the following components: broad range narrow range

1. electrically conducting, processable polymer 0.1-5 0.2-2

2. dispersant 0.1-5 0.2-2 3. non-ionic polyhydroxy compound 0.1-20 0.2-10

4. ionic dopant 0.1-20 0.2-10

5. solvent remainder to 100% In a particularly preferred embodiment, the components in weight percent are as follows: amount of the polymer is 0.2-1 %, such as about 0.5 %; amount of the dispersant is 0.2-1 %, such as about 0.8%; amount of the polyhydroxy compound is 1-10 %, such as about 5 %; and amount of the dopant is 1-10 %, such as about 5 %.

The solvent, particularly water, is an indispensible coating component since the coating composition must be film-forming and processable. If not enough or too much solvent is used, the resulting coating composition will not be film-forming and/or processable and the composition will not be suitable for purposes herein. The polymer and the dispersant are typically used in the form of an aqueous solution; the polyhydroxy compound is typically dissolved in a lower alkyl alcohol and then mixed into the aqueous solution; and the dopant is typically dissolved in water and then mixed into the aqueous solution, which is the final solution. The polymers contemplated herein are electrically conducting polymers such as poly anilines, polypyrroles, polythiophenes, polyphenylenes, and poly(p-phenylene vinylene). The polyaniline family is attractive for its ability to form processable conductive forms at relatively low cost in bulk amounts. Unfortunately, due to the presence of benzidine moieties in the polymer backbone, which might yield toxic (carcinogenic) products upon degradation, interest in polyaniline chemistry has been limited. The preferred polymer for purposes herein is selected from polyethylene dioxythiophene containing the following repeating unit:

where R¹ and R² are selected from phenyl and alkyl groups containing 1-15 carbon atoms.

Since processability is an important facet of the polymer and since processability is reduced by elongating the chain(s) on the molecule and including some substituents, in a preferred embodiment, a suitable polymer has R¹ and R² that are selected from hydrogen, methyl and ethyl moieties. The most preferred polymer is a polyloweralkylene dioxythiophene, particularly poly (3,4 - ethylene dioxythiophene where R¹ and R² are hydrogen molecules. Weight average molecular weight of the polymer herein is such that it forms a solution with the dispersant in water. Weight average molecular weight is estimated to be in the range of 10,000 to 150,000. Any suitable dispersant can be used to either solubilize or to disperse the polymer in water or another suitable solvent. For polyethylene dioxythiophene polymer, polystyrene sulfonic acid dispersant is suitable. Weight average molecular weight of a polymeric dispersant, if it is a polymer, is such that it forms a solution with the polymer in water. Weight average molecular weight of the polystyrene sulfonic acid is estimated to be in the range of to

The polyhydroxy compound appears to improve long-range order of conducting molecules of the polymer and reduces defects between polymer domains. Suitable polyhydroxy compounds are linear and have the general structure CH ₂ OH -(- OH -)_n - CH ₂ OH where n is greater than 1 but less than 20, typically 1-10. Suitable herein are polyhydroxy compounds that include carbohydrate sugars having the formula (CH₂ O) _x which are mono-, di-, tri-, and polysaccharides. Many polyhydroxy compounds that are suitable herein do not have the formula (CH₂ O) _x and are not sugars. These include rhamose, D-sorbitol, glycerol, etc. Certain surfactants were tried but the resulting films were unstable in that the films were too soluble in water. Glucose, ethylene glycol and diethylene glycol also produced films that were too soluble in water. Particularly suitable here are the polyhydroxy compounds containing at least three hydroxyl (OH) groups and include sorbitol, glycerol and the like.

The fourth component in the composition is an ionic organic dopant which further improves electrical conductivity of the composition but which appears to reduce its transparency somewhat. So, a suitable ionic dopant is any component that is compatible with components of the composition, improves its conductivity and which is not unduly deleterious with respect to light transmission when the composition is applied onto the substrate. Specific examples of suitable herein dopants include sulfosalicylic acid, sodium salt of anthraquinome-2 sulfonic acid and m-cresol. Other suitable ionic and organic dopants can also be used.

It appears that the polyhydroxy compound and ionic dopant components of the coating composition act synergistically with respect to electrical conductivity and optical transparency of the composition. Furthermore, there does not appear to be any chemical reaction taking place, as it relates to formation of compounds, when the composition components are combined.

The fifth component in the coating composition is a solvent which makes it possible to make a film of the composition and enable preparation of a processable coating composition. Typically, the solvent is water. Preparation of the coating composition involves combining a number of solutions which contain the composition components. The first solution is an aqueous solution of the polymer and the dispersant; the second solution is an alcoholic solution of the polyhydroxy compound; and the third solution is an aqueous solution of the ionic dopant. Typically, the coating composition is prepared by mixing the three solutions at room temperature and then applying them to a substrate, followed by annealing at a suitable temperature and for a sufficient duration that does not damage the substrate. Annealing or heating the composition results in molecular alignment self organization, concomitant improved electrical conductivity and physical integrity.

Having described the invention, the following examples are given as particular embodiments thereof. It is understood that the examples are given by way of illustration and are not intended to limit the specification or claims in any manner.

Examples Commercial Batron P polyethylene dioxythiophene aqueous solution is available from the German company Bayer AG. The Batron P is an aqueous solution composed of 0.5 % by weight poly (3 ,4 - ethylenedioxythiophene) polymer and 0.8% by weight polystyrene sulfonic acid dispersant. A second solution was prepared by dissolving 0.8g D- sorbitol sugar-like substance and 0.6 g glycerol sugar-like substance in 1ml methanol. A third solution was prepared by gradually dissolving at 70-80°C 0.05g of sodium salt of anthraquinone -2- sulfonic acid ionic dopant and O.lg of sufosalicylic acid ionic dopant in 2ml of deionized water. The coating composition solution was prepared by pouring into a 100-ml. glass flask 10 ml of the Batron P aqueous solution containing the polymer and the dispersant, 1 ml of the second alcohol solution containing the sugar-like substances and the third aqueous solution containing the ionic dopants. The flask contents on weight percent basis was as follows: polymer 0.53 dispersant 0.82 polyhydroxy compound 0.5-20 ionic dopant 0.5-8 water remainder to 100%

Cleaned solid substrates were used, the substrates being polyethylene terephthalate (PTE) measuring about 2.2 cm on a side with a thickness of about 250 μm. The conductivity measurements were performed at different times of 0, 1, 2 and 24 hours.

Surface resistance (conductivity) was measured using Signatone Four-Point Probe Resistivity Mapping System(SYS-301) connected to Keithley 224 Programmable Current Source and Keithley 196 System Digital Multimeter. Film transparency was measured for every substrate by using Gary 5 UV-vis Spectro-meter at transmittance mode. The film thickness was determined by using Profilometer. The accuracy of film thickness was also confirmed by Scanning Electron Microscope.

Example 1 The PTE plastic substrates were used as received i.e., without any surface treatment or cleaning, gave water contact angle of 45° . The above coating composition was spin- coated on the substrates with the following result:

Spin Rate Surface Resistance Optical transmittance

(rprn) RJΩ/Ω) (TΨo)

500 no film no film

1000 1500 90

2000 2300 95 No film was formed at 500 rpm probably due to the fact that the substrate surfaces were not cleaned and because of the low speed. The film formed at 1000 rpm and at 2000 rpm was not uniform in that some areas on the substrates were left uncoated.

Example 2

The plastic substrates, cleaned by soaking for 15 minutes under sonication (Method I) gave water contact angle of 40°. A mixture of 10 ml the Batron P aqueous solution and 0.5g glycerol dissolved in 1ml deionized water was spin coated on the cleaned substrates with the following results.

Spin Rate Surface Resistance Optical transmittance

( prn) R-(ΩQ ___ 500 950 85

1000 1300 90

2000 2200 95

Example 3 The plastic substrates, cleaned by dipping into 10% HCI solution for 10 minutes under sonication then were sequentially rinsed with deionized water, methanol, and acetone (Method II) gave water contact angle of 35°. A mixture of 10 ml of the Batron P aqueous solution and 0.5g glycerol dissolved in 1ml of deionized water was spin coated on the cleaned substrates with the following results: Spin Rate Surface Resistance Optical transmittance

(rpm) R- (ΩQ (T%

500 880 84

1000 1300 87

2000 2200 92 Example 4

The plastic substrates, cleaned by being kept in 10% KOH in isopropanol for 20 minutes then washed sequentially with acetone and methanol (Method III) gave water contact angle of 25°. A mixture of 10 ml of the Batron P aqueous solution and 0.5g glycerol dissolved in 1ml of deionized water was spin coated on the cleaned substrates with the following results:

Spin Rate Surface Resistance Optical transmittance

(rpm) R.(Ω <T%)

500 880 84

1000 1300 87 2000 2200 92

Example 5 The plastic substrates, cleaned by first treating with plasma stream inside a plasma generator for ^lΔ hour and then by rinsing sequentially with methanol and acetone (Method IV) gave water contact angle of about 3° A mixture of 10 ml of the Batron P aqueous solution and 0.5g glycerol dissolved in 1ml of deionized water was sp coated on the cleaned substrates with the following results.

Spin Rate Surface Resistance Optical transmittance (rpm) R_S (Ω/D) (T%) 500 790 86

1000 1300 90

2000 2000

Example 6 Only the Batron P solution was spm coated on plastic substrates cleaned by keeping the substrates in 10% KOH in isopropanol solution for 20 minutes and then washed sequentially m acetone and methanol (Method m ). The following results were obtained:

Spin Rate Surface Resistance Optical transmittance

(rpm) R- CΩ/D) (T%)

500 2800 86

1000 3600 89

2000 5800 94

It should be apparent from the above results that although transmittance is good, surface resistance of the film is too high.

Example 7 Mixtures of 10 ml of the Batron P solution mixed with different amounts of sulfosalicylic acid (SSA) dopant were prepared according to the general procedure, but m absence of glycerol, and then spm-coated on PET plastic substrates pre-cleaned by Method III. The SSA dopant amounts were 0.05g, O.lg, 0.2g, 0.4g, 0.6g, and 0.8g The following results were obtained:

SSA Amount Spin Rate Surface Resistance Optical

Transmittance sl (rpm) R.(Ωθ (T%)

The above results show a reduction in surface resistance and a concomitant reduction in light transmittance. This trend is clearly represented in Fig. 3. Although at 0.2g SSA the surface resistance is an acceptable 330 Ω/D, transmittance is an unacceptable 64%. Example 8

Five mixtures of the coating composition were prepared by mixing 10 ml of the

Batron P aqueous solution with different amounts of glycerol and then spin coated on plastic substrates cleaned by Method III. Test results are given below:

Glycerol Amount Spin Rate Surface Resistance Optical

Transmittance gl (rpm) R_:(Ω/D) (T%)

The above data shows dramatic results which are also self-evident in Fig. 4. Unlike the coating consisting of the polymer, dispersant and the ionic dopant, surface resistance and transmittance are now decoupled, meaning that a variation in one is not accompanied by a variation in the other. Results in the above table, represent a demonstration of the ability to vary surface resistance without varying optical transmission.

Example 9

In order to see the effect of adding the ionic dopant SSA and the non-ionic sugar-like substance glycerol, mixtures of the Batron P solutions, the SSA solutions and glycerol solutions were prepared varying the amount of glycerol. 10ml of the Batron P solution was used. The SSA solution was O.lg SSA dissolved in 1ml of methanol. The glycerol solutions contained varying amounts of glycerol dissolved in 1ml of deionized water. The amounts of glycerol varied from 0.5g to 2g. Results are set forth below:

Glycerol Amount Spin Rate Surface Resistance Optical

Transmittance

Lgl ∑E ) R-(Ω/D) (T%)

Again, the decoupling of the surface resistance and transmittance variations with glycerol concentration variation is seen for all speeds. An outstanding coating composition appears to be one prepared by mixing 10 ml Batron P aqueous solution, 1 ml methanol containing dissolved therein O.lg sulfosalicylic acid, and 1 ml deionized water containing dissolved therein 1.6g glycerol. The composition is spin-coated on a plastic substrate at 1000 rpm and annealed or heated at 120 ° C for 2 minutes. The surface resistance for this coating was 480 Ω/D and its optical transmittance was 81 %.

Example 10 The coating compositions here were mixtures of 10 ml Batron P solution, 1 ml methanol containing 0.05g of sodium salt anthraquinone -2- sulfonic acid ionic dopant dissolved therein and 1 ml methanol containing O.lg sulfosalicylic acid ionic dopant dissolved therein and different amounts of glycerol varying from 0.05g to 1.5 g. Results are given below:

Glycerol Amount Spin Rate Surface Resistance Optical Transmittance

Example 11 In this example, comparison was made of surface resistance and transmittance values for glycerol and mixtures of glycerol and different dopants for coating compositions spin- coated at 1000 rpm on PET plastic substrates. The first coating composition was a mixtire of 10 ml Batron P aqueous solution and 1 ml methanol having dissolved therein 0.1 g sulfosalicylic acid (SSA). The second one was a mixture of 10 ml Batron P solution and 1 ml methanol having dissolved therein 0.6 g glycerol. The third one was a mixture of 10 ml Batron P solution and 1 ml methanol having dissolved therein 0.1 sulfocalicylic acid and 0.6 g glycerol. The fourth one was a mixture of 10 ml of Barton P first solution and a second solution of 1 ml methanol and 1 ml water having dissolved therein 0.1 g sulfosalicylic acid, 0.6 g glycerol and 0.05 g sodium salt of anthraquinone-2-sulfonic acid (AQSA).The water was needed to solubilize AQSA. The data is represented in the graph of Fig. 5 which shows a large variation of surface resistance from 1400 Ω/D to 400 Ω/D while light transmission remains more or less constant at about 80 %.

Example 12

This example demonstrates decoupling of surface resistance and transmittance. Here

10 ml of Batron P solutions were mixed with varying amounts of D-sorbitol. The sorbitol was dissolved in 1 ml of deionized water. Amount of sorbitol varied from 0.2 to 1.6 g. Test data is given below:

Sorbitol Amount Spin Rate Surface Resistance Optical

Transmittance

The above data demonstrates the decoupling effect of surface resistance and light transmission whether glycerol or sorbitol are used. Thus was demonstrated the new concept that surface resistance of a conducting polymer film can be tuned without compromising the optical transmission by adding a non- ionic sugar-like carbohydrate addition and an ionic dopant.

While presently preferred embodiments have been shown of the novel electronic display devices and the coating composition therefor, and of the several modifications discussed, persons skilled in this art will readily appreciate that various additional changes and modifications may be made without departing from the spirit of the invention as defined and differentiated by the following claims.

Claims

What is claimed is:

1. A processable composition having surface resistance of about 700 Ω/D or less and optical transmittance of about 70% or higher comprising the following components given in weight percent: electrically conducting polymer 0.1-5 dispersant for said polymer 0.1-5 polyhydroxy compound 0.1 -20 ionic dopant 0.1-20 solvent to 100% the polyhydroxy compound has the formula CH ₂ OH -(- OH -)_n - CH ₂ OH where n is up to 20.

2. The composition wherein amount of said polymer is 0.2-2 %, amount of said dispersant is 0.2-2% by weight, amount of the said polyhydroxy compound is 0.2-10% by weight and amount of said dopant is 0.2-10% by weight and.

3. The composition of claim 2 wherein said components are in a final aqueous solution and n is 1-10.

4. The composition of claim 3 wherein said polymer and said dispersant are in a dilute aqueous solution before being combined into said final solution, wherein said polyhydroxy compound is in a dilute alcohol solution before being combined into said final solution, and wherein said dopant is in a dilute aqueous solution before being combined into said final solution.

5. The composition of claim 4 wherein said polymer is selected from the group consisting of polyethylene, polyaniline, their derivatives and precursors, and mixtures thereof.

6. The composition of claim 4 wherein said polymer contains the following repeating unit:

wherein R¹ and R² are individually selected from the group consisting of hydrogen atoms, phenyl groups, alkyl radicals of 1-15 carbon atoms, and mixtures thereof, said polymer is solid and its weight average molecular weight is 10,000 to 150.000 .

7. The composition of claim 6 wherein R¹ and R² are selected from the group consisting of hydrogen atoms, methyl radicals, ethyl radicals, and mixtures thereof; and wherein said polyhydroxy compound is a carbohydrate containing 3 or more hydroxyl groups.

8. The composition of claim 7 wherein said dispersant is polystyrene sulfonic acid, said polyhydroxy compound is selected from the group consisting of glycerol, sorbitol, glucose, and mixtures thereof; and wherein said dopant is selected from the group consisting of sulfosalicylic acid, sodium salt of anthraquinone -2- sulfonic acid, cresol, and mixtures thereof.

9. The composition of claim 7 wherein said final solution is a methanol - water solution; said dispersant is polystyrene sulfonic acid with average weight molecular weight in the range of 100,000 to 2000; said dopant is selected from the group consisting of sulfosalicylic acid, sodium salt of anthraquonone-2-sulfonic acid, m-cresol, and mixtures thereof; and said polyhydroxy compound is selected from the group consisting of glycerol, D-sorbitol and mixtures thereof.

10. The composition of claim 9 wherein R¹ and R² are hydrogen atoms; amount of said polymer is about 0.5 % by weight and amount of said dispersant is about 0.8 % by weight.

11. An electronic display device comprising a first transparent substrate and a first dry coating composition disposed on said substrate, the composition is processable, has surface resistance of about 700 Ω/D or less and optical transmittance of about 70% or higher, the dry composition comprising is prepared from the following components given in weight percent: electrically conducting polymer 0.1-5 dispersant for said polymer 0.1-5 polyhydroxy compound 0.1-20 ionic dopant 0.1-20 solvent to 100 % the polyhydroxy compound has the formula CH ₂ OH -(- OH -)_n - CH ₂ OH where n is up to 20 and the solvent is water.

12. The device of claim 11 wherein the substrate is plastic and wherein amount of the polymer is 0. 2-2 % , amount of the dispersant is 0.2-2 % , amount of the polyhydroxy Inventors: Shashidar et al Patent Application

Serial Number: Navy Case Number: 83,177 compound is 0.2-10 % , and amount of the dopant in 0.2-10 % .

13. The device of claim wherein the polymer is selected from the group consisting of

polyloweralkylene dioxythiophene , derivatives and precursors thereof, and mixtures

thereof, the polymer having weight average molecular weight of 10,000 to 150,000.

14. The device of claim 13 wherein the polymer contains the following repeating

unit:

wherein R¹ and R² are individually selected from the group consisting of hydrogen atoms, phenyl groups, alkyl radicals of 1-15 carbon atoms, and mixtures thereof.

15. The device of claim 14 wherein R¹ and R² are individually selected from the group consisting of hydrogen atoms, methyl radicals, ethyl radicals, and mixtures thereof; and wherein the polyhydroxy compound is a carbohydrate containing 3 or more hydroxyl groups.

16. The device of claim 15 wherein the dispersant is polystyrene sulfonic acid having weight average molecular weight of 100,00 - 200,000, the polyhydroxy compound is

selected from the group consisting of glycerol, sorbitol and mixtures thereof; and wherein the dopant is selected from the group consisting of sulfosalicylic acid, sodium salt of anthraquinone -2- sulfonic acid, cresol, and mixtures thereof.

17. The device of claim 16 wherein in the polymer repeating unit R¹ and R² are

hydrogen atoms and amount of the polymer is about 0.5 % and amount of the dispersant is about 0.8 %.

18. The device of claim 16 the composition of claim 9 wherein R¹ and R² in the repeating unit are hydrogen atoms, amount of the polymer is about 0.5 % and amount of the dispersant is about 0.8 %.

19. The device of claim 16 including a second transparent plastic substrate with a second coating composition disposed on its surface spaced from the first coated substrate, with the first and second coatings facing each other, a first and a second aligning surfaces disposed against the respective coatings spaced from each other, and liquid crystal material disposed in the space between the first and the second coatings.

20. The device of claim 16 including a second transparent plastic substrate with a coating composition disposed on its surface spaced from the first coated substrate, with the first and second coatings facing each other, a first electrode disposed against the first coating, a second electrode disposed against the second coating and being spaced from the first coating, and a light emitting material disposed between the first and the second coatings.