SE2250677A1 - Conductive composition comprising dialcohol-modified cellulose and uses thereof - Google Patents

Abstract

Abstract The present disclosure relates to a composition comprising a dialcohol cellulose and an electrically active material and uses thereof.

Description

Technical field The present disclosure relates to a composition for producing a dialcohol-modified cellulose-based bio-ink. The disclosure further relates to electrically conductive materials based on said composition, methods of manufacturing and uses thereof.

Background Bio-based electronics is a rapidly growing area especially for wearable energy storage, energy harvesting and biomedical devices. For this type of applications, conducting polymers such as PEDOT:PSS are important electroactive components due to their processability, electrochemical properties and charge transfer abilities. However, often these polymers require doping with solvents such as ionic liquids, concentrated sulfuric acid or dimethyl sulfoxide (DMSO), to increase their electronic conductivity for application in electronic devices. Another important aspect is the processing of these conducting polymers. Usually, they are processed with two-dimensional techniques, for example inkjet printing, laser or substrate patterning. Additive manufacturing of conducting polymers is also emerging as an alternate route to obtain 3D patterning. However, the literature on this subject is still sparse and there are only few published studies for 3D bio-printing of conducting polymers by using matrix materials such as hyaluronic acid, alginate, chitosan or ionic liquids. The inks developed so far for 3D printing of conducting polymers have multi-step preparation processes and the conducting polymer needs to be the major component of the composite ink to achieve a good conductivity. Hence, there is a need for efficient, bio-based conducting bio-inks, without addition of any organic solvent.

Cellulose fibers cannot be melt processed, and hence not 3D printed, unless a significant amount of matrix polymer is added, typically more than 40-50% (Bengtsson et al., 2007). Furthermore, due to their large size, there is not only a risk for clogging of the printing nozzle, but also limitations to the resolution that can be achieved. As a result, for the purpose of 3D printing, cellulose fibers can be dissolved in cold alkali, ionic liquids or different organic solvents, fibrillated into nanomaterials such as cellulose nanofibrils (CNFs), or hydrolyzed to cellulose nanocrystals (CNCs), to prepare bio-ink. Production of such nanocelluloses is, however, an energy (chemical and/or P6334SEOO mechanical) intensive process. Thus, the need for an easy-to-prepare, 3D-printable conducting bio-ink remains.

Summary The present disclosure relates to a novel electrically conducting bio-ink that comprises modified cellulose fibers, wherein the cellulose has been partly converted to dialcohol cellulose, hereafter referred to as dialcohol-modified cellulose (DALC) fibers. DALC fibers are highly flexible, ductile and can be melt-processed. The composition disclosed herein allows for a bio-ink alternative that allows the energy intensive step of nanocellulose preparation to be omitted. Furthermore, the content of the conductive material required may be reduced without compromising the conductivity of the bio-ink of the disclosure. ln one aspect, the present disclosure relates to a composition comprising a dialcohol cellulose and an electrically active material. ln one aspect, the present disclosure relates to an electrically conductive material comprising the composition of the present disclosure. ln another aspect, the present disclosure relates to a method of manufacturing an electrically conductive material comprising a step of applying the composition of the present disclosure. ln one aspect, the present disclosure relates to a device manufactured with the electrically conductive material manufactured according to the present disclosure. ln one aspect, the present disclosure relates to a use of electrically conductive material manufactured according to the present disclosure. ln one aspect, the present disclosure relates to a method of manufacturing the composition of the present disclosure.

P6334SEOO Description of Drawings Figure 1 shows a schematic process for preparing dialcohol-modified cellulose fibers for use herein, Figure 2a, 2b, 2c and 2d shows results of a rheology analysis of a 3D conducting ink at different solids content obtained from an embodiment of the composition as disclosed herein, Figure 3 shows an AFM image of PEDOT:PSS particles decorated on dialcohol cellulose nanofibrils in the fibers, Figure 4a and 4b shows surface (fig. 4a) and cross section (fig. 4b) images of a 3D printed film obtained from an embodiment of the composition as disclosed herein, Fig. 5a and 5b shows WAXS results of embodiments of 3D printed films before (fig. 5a) and after (fig. 5b) washing, Fig. 6a and 6b compares the wetting properties of a 3D printed film using a non-DALC composition and a 3D printed film of a composition disclosed herein before and after washing, respectively, Figs. 7a - 7d shows different 3D printed structures using embodiment of the compositions disclosed herein, Fig. 8 shows the electrical conductivity of a 3D gel printed using an embodiment of a composition disclosed herein, Fig. 9 shows electrical conductivity measurements of other 3D printed films soaked in water or phosphate buffer solution (PBS) using an embodiment of a composition disclosed herein, Fig. 10a shows relative resistance as a function of stretching a 3D serpentine pattern printed using an embodiment of a composition disclosed herein, P6334SEOO Fig. 10b shows a simple conductive function of the serpentine pattern of Fig. 10a, Fig. 11 shows a schematic test setup comprising a reference electrode, RE (Ag/AgCl); counter electrode, CE (Pt e|ectrode); and working electrode, WE (3D printed sample mounted on Pt wire) for electrochemical testing a 3D sample printed using a composition disclosed herein, Figs. 12 - 16, shows different measurements obtained from the test setup of Fig. 11, Fig. 17 shows an embodiment of a fabricated supercapacitor device comprising an embodiment of the composition as extruded as disclosed herein, Fig. 18 shows galvanostatic charge/discharge curves of the device of Fig. 17, Fig. 19a and 1b, shows ECG measurements from the wearable electrode device comprising an embodiment of the composition as extruded as disclosed herein Detailed description "Dialcohol cellulose" or "DALC" or "dialcohol modified cellulose fibers" refers to modified cellulose that may be obtainable, for example, by a method, as illustrated in Fig. 1, comprising oxidizing cellulose in a fiber suspension to dialdehyde cellulose followed by reduction of dialdehyde cellulose to obtain the dialcohol cellulose. Some of the methods to obtain DALC are further discussed in patent application WO2018/135994. The terms also incorporate DALC nanofibrils, cellulose-based nanofibrils obtainable by microfluidization or mechanical processing of DALC fibers. lt is to be understood that while both cellulose nanofibrils and fibers that have been dialcohol modified can be referred to as dialcohol cellulose, nanofibrils have a diameter of a few nanometers, such as less than 1000 nm, preferably less than 500 nm, or less than 200 nm, or less than 100 nm, or 50 nm, while fibers are in the micrometer range, may have but not limited to a diameter of at least 1 um, such as at least 5 um, such as at least 8 um, such as at least 12 um. The length of the fibers and nanofibrils may be in a micrometer or a millimeter range.

P6334SEOO ln general when referring to DALC cellulose it is understood that a certain amount of the cellulose has been modified. Typically the modification desired depends on the application. However, generally for the applications disclosed herein a degree of modification or degree of substitution 10% - 50% is sufficient. However, lower or even higher degrees of substitution or modification may also be used.

"PEDOT:PSS" is a polymeric compound, also called a polymer complex, comprising poly-3,4-ethylenedioxythiophene (PEDOT) and polystyrene sulfonate (PSS) in any ratio. PEDOT:PSS is ready available from multiple suppliers and is commonly used in conductive bio ink as it is easy to use. lf nothing else is mentioned a PEDOT:PSS ratio of 1:2.5 is used, however, it is generally understood that changing the ratio in what is commonly available doesn't affect the use in any considerable way.

As used herein, the term "plasticizer" commonly refers to a substance or material incorporated in the matrix forming material to increase its flexibility or workability. Many plasticizers tend to decrease the intermolecular forces between polymer chains, resulting in the increased flexibility and compressibility, or they may exert a plasticizing effect since they cause discontinuities in a polymer matrix. Examples of classes of plasticizers are saccharides (mono-, di- or oligosaccharides), alcohols, polyols, acid, salts, lipids and derivatives (such as fatty acids, monoglycerides, esters, phospholipids) and surfactants. Specific examples of suitable plasticizers include but are not limited to: glucose, fructose, sorbitol, polyethylene glycol, glycerol, propylene glycol, lactitol, sodium lactate, hydrated hydrolyzed starches, trehalose, or combinations thereof such as honey. Other suitable plasticizers for use in the present disclosure include DMSO and ionic liquids.

As used herein, the terms "cross-linking agent" or "cross-linker" refers to chemical entities capable of forming cross-linking chains between polymers; as well as agents capable of providing cross-linking of polymer chains in the presence of the appropriate reagents, such as gamma-irradiation, or other types of electromagnetic radiation, or electron bombardment.

P6334SEOO DALC-based bio-ink One embodiment of the present disclosure provides for a composition comprising, a dialcohol cellulose and an electrically active material. The dialcohol cellulose in the present disclosure can be in the form of DALC fibers or DALC nanofibrils. DALC fibers and nanofibrils can be prepared using methods known by a person skilled in the art. For example, DALC fibers can be obtained by oxidizing cellulose in a fiber suspension to dialdehyde cellulose followed by reduction of dialdehyde cellulose to obtain the dialcohol cellulose. lf desired, DALC nanofibrils can then be obtained by microfluidization or mechanical processing of DALC fibers. ln one embodiment, the composition further comprises a plasticizer.

The electrically active material in the bio-ink refers to any material that transmits a current, for example, an electrically conductive material. ln one embodiment, the composition comprises between 5 wt% and 70 wt% of the electrically active material. ln another embodiment, the composition comprises between 10 wt% and 50 wt% of the electrically active material. ln one embodiment, the composition comprises 40 %wt of the electrically active material. ln one embodiment, the composition comprises between 30 wt% and 95 wt% of the dialcohol cellulose. ln one embodiment, the composition comprises between 10 wt% and 80 wt% of the plasticizer, such as between 15 wt% and 75 wt% of the plasticizer. Alternatively, the composition comprises between 1 vol% and 10 vol% of the plasticizer.

The electric conductivity desired may vary for different applications. E.g. for wearable devices an electric conductivity of around 0.1 S/cm is commonly used, but for e.g. electronic paper an electric conductivity of 100, or even 150, S/cm may be desired. Thus, in some embodiments, the composition has an electric conductivity between 0.05 S/cm and 150 S/cm, such as between 0.1 S/cm and 100 S/cm, such as 40 S/cm, such as 35 S/cm, such as 30 S/cm. ln one embodiment, the composition has an electric conductivity of at least 0.05 S/cm, such as at least 0.1 S/cm, such as at least 0.5 S/cm, such as at least 1 S/cm, preferably it has a conductivity of at least 0.1 S/cm. However, P6334SEOO in certain embodiment the electric conductivity may be as high as 100, or even 150 S/cm. ln some embodiments, the plasticizer comprises a polyol. Examples of polyol plasticizer include a glycerol, a sorbitol and an erythritol. ln a preferred embodiment, the plasticizer comprises glycerol. As illustrated in the examples, glycerol, combined with DALC and PEDOT:PSS, enhanced the separation of PEDOT and PSS, thus increasing the conductivity of the composition. The addition of glycerol also enabled the composition to retain the gel nature of the ink, increased wet stability and adhesion of the ink to the substrate. Wet stability and the ability of the composition to retain moisture can prolong the shelf life of devices based on the composition of the present disclosure compared to conventional hydrogel materials. ln some embodiments, the plasticizer comprises Dl\/ISO. ln some embodiments, the plasticizer comprises ionic liquids. The term "ionic liquid" is commonly defined as molten salts, which are comprised of ions and are liquids at Ceftalfl tempefatüfeS. ln one embodiment of the present disclosure the electrically active material comprises an electrically conducting polymer. lt is understood that by the term "electrically conducting polymer' is also meant a mixture or a complex comprising several polymers, which may be with or without electrically conducting properties on their own, provided that the mixture exhibits electrically conducting property. The electrically conductive polymer may, for example, comprise one or more polymers selected from the group consisting of polyphenylenes, polypyrenes, polyazulenes, polynaphthalenes, polyacetylenes (PAC), poly-p-phenylene vinylene (PPV), polypyrroles (PPY), polyazepines, polyanilines (PANI), polythiophenes (PT), poly-3,4- ethylenedioxythiophene (PEDOT), toluenesulfonyl (Tos) and a polystyrene sulfonates (PSS). ln a preferred embodiment, the electrically conducting polymer comprises PEDOT:PSS.

P6334SEOO ln some embodiments, the composition comprises between 5 wt% and 70 wt% of the electrically conducting polymer. ln some embodiments, the composition comprises between 10 wt% and 50 wt% of the electrically conducting polymer. ln a preferred embodiment, the composition comprises 40 wt% of the electrically conducting polymer. ln some embodiments, the electrically active material comprises an electrically conducting carbon material. By the term "electrically conducting carbon material" is meant any carbon allotrope that conducts electricity. Based on the dimensional structure for electron confinement said carbons can be classified as OD, 1D, 2D and 3D carbons. ln some embodiments the electrically conducting carbon material is selected from the group consisting of 1D carbons, 2D carbons and 3D carbons. ln one embodiment, the 3D carbon is a graphite. ln one embodiment, the 2D carbon is a graphene. ln one embodiment, the 1D carbon is a carbon nanotube. ln some embodiments, the electrically active material comprises an electrically conducting 2D material. Said 2D material may be an organic or an inorganic conducting material, characterized by a 2D structure. ln one embodiment, the electrically conducting 2D material is selected from the group consisting of a graphene, a MXenes and a Molybdenum disulfide (MoSz).

One embodiment of the present disclosure provides for a method of manufacturing the composition of the present disclosure, said method comprising a step of mixing a dialcohol cellulose with an electrically active material, thus obtaining the composition. ln one embodiment, the method of manufacturing the composition further comprises a subsequent step wherein the plasticizer is mixed in with the dialcohol cellulose and the electrically active material.

P6334SEOO Processing of the bio-ink The bio-ink of the present disclosure can be further processed into an electrically conductive material. Examples of processing techniques include but not limited to extruding, printing or solution processing techniques.

One embodiment of the present disclosure provides for an electrically conductive material comprising the composition of the present disclosure. ln some embodiments the composition has been applied by 3D-printing, 2D-printing, screen printing, stencil printing, blade-coating, melt-processing, molding, slot die coating, inkjet printing, laser printing, solution processing, vacuum filtration, solvent casting and/or paper making techniques, thus obtaining said electrically conductive material. ln some embodiments, the composition is at least partly dried before, during and/or after applying the composition. ln some embodiments, the composition is at least partly cured before, during and/or after applying the composition.

A cross-linker can be added to the composition to give it a 3D network structure. ln one embodiment of the present disclosure, the composition further comprises a cross- linking agent. The cross-linking agent can be added before, during and/or after applying the composition. ln some embodiments, the cross-linking agent is selected from the group consisting of ionic cross-linkers, photo cross-linkers and covalent cross- linkers. ln some embodiments, the electrically conductive material has an electrical conductivity between 0.05 S/cm and 150 S/cm, such as between 0.1 S/cm and 100 S/cm, such as 40 S/cm, such as 35 S/cm, such as 30 S/cm. ln one embodiment, the electrically conductive material has an electrical conductivity of at least 0.05 S/cm, such as at least 0.1 S/cm, such as at least 0.5 S/cm, such as at least 1 S/cm, preferably it has a conductivity of at least 0.1 S/cm. However, in certain embodiment the electrical conductivity may be as high as 100, or even 150 S/cm.

Psss4sEoo One embodiment of the present disclosure provides for a method of manufacturing an electrically conductive material of the present disclosure, said method comprising a step of applying the composition of the present disclosure. ln some embodiments, applying the composition comprises 3D-printing, 2D-printing, screen printing, stencil printing, blade-coating, melt-processing, molding, slot die coating, inkjet printing, laser printing, solution processing, vacuum filtration, solvent casting and/or paper making techniques. ln some embodiments, the method further comprises (an) additional step(s) of adding a cross-linking agent before, during and/or after applying the composition.

Applications of the DALC bio-ink-based materials One embodiment of the present disclosure provides for a device manufactured with the electrically conductive material comprising the composition of the present disclosure. Such device can, for example, be an electronic device, an energy storage device, a sensor, an electrode, an electronic device or an automotive device.

One embodiment of the present disclosure provides for a use of the electrically conductive material of the present disclosure in an electronic device.

One embodiment of the present disclosure provides for a use of the electrically conductive material of the present disclosure in an energy storage device.

One embodiment of the present disclosure provides for a use of the electrically conductive material of the present disclosure in a sensor. Such sensors may for example be capacitive sensors which can be used in numerous manners. For example the electrical conductive material may be integrated into a material so that a change in capacitance is detected when the characteristics of the material changes. This may for example be the moisture content of the material, the size/dimensions of the material and/or the deformation of the material. ln other embodiment the change in capacitance may be detected by an outside object, such as a hand or a finger that touches the sensor and thus generates a change in capacitance. 1 1 P6334SEOO One embodiment of the present disclosure provides for a use of the electrically conductive material of the present disclosure in an electrode.

One embodiment of the present disclosure provides for a use of the electrically conductive material of the present disclosure in an automotive device.

Examples Exampie 1. Preparation and assessment of the DALC-based conducting inks Materials and methods Materials PEDOT:PSS (CleviosTM PH 1000, 1.3 wt%) from Heraeus. Glycerol, sodium periodate, sodium borohydride, Polyvinyl alcohol (PVA), and sulphuric acid were all purchased from Sigma Aldrich. All the chemicals were used without any further purification.

Dialcohol-modified cellulose fibers were then prepared according a previously reported method (Larsson et al., 2016). Briefly, beaten bleached softwood kraft fibers (fines removed, fiber concentration 15 g/L) were oxidized to dialdehyde cellulose using sodium periodate (1 .35 g per g of fiber). The reaction proceeded for 37 h, in the dark and at room temperature, and the pulp was washed thoroughly after completion of reaction. To determine the aldehyde content, hydroxylamine titration was used. Dialdehyde fibers were reduced to dialcohol cellulose fibers by adding sodium borohydride (0.4 g per g of fiber) and reaction carried out in 0.01 M phosphate buffer for 3 h. Subsequently, the fibers were washed thoroughly and stored at 4 9G until further use. To prepare dialcohol modified cellulose nanofibrils, dialcohol-modified cellulose fibers are microfluidized.

Preparation of DALC-based inks without plasticizer To prepare DALC based conducting ink, dialcohol-modified cellulose fibers (degree of modification or degree of substitution 10% - 50%) or dialcohol-modified cellulose nanofibrils (degree of modification 10%- 50%) were mixed with PEDOT:PSS at different weight ratios, where dialcohol-modified cellulose (fibers or nanofibrils) comprised of at least 30 wt%, preferably between 30 and 95 wt% and PEDOT:PSS 12 Psss4sEoo comprises of at least 5 wt%, preferably between 5 and 70 wt% of the total composition of the ink.

Preparation of DALC-based inks with plasticizer To prepare the inks, dialcohol-modified cellulose fibers (degree of modification or degree of substitution 10% - 50%) or dialcohol modified cellulose nanofibrils (degree of modification 10% - 50%) and PEDOT:PSS were mixed in different dry weight ratios where dialcohol modified cellulose (fibers or nanofibrils) comprised of at least 30 wt%, preferably between 30 wt% and 95 wt% and PEDOT:PSS comprises of at least 5 wt%, preferably between 5 wt% and 70 wt% of the total composition of the ink. The workflow of said preparation is shown in Fig.1b. All the inks also contained a plasticizer that comprised between 1 vol% and 10 vol% of the total composition (corresponds to approximately between 10 wt% and 80 wt% of the total composition). 1 vol%, 5 vol% and 10 vol% glycerol was used in preparation of the inks. lnks were placed in the fume- hood to evaporate water to achieve desired solids content.

Rheological measurements A DHR-Z rheometer (TA Instruments, New Castle, DE, USA) equipped with a 25 mm parallel-plate geometry (1 mm gap distance), was used to measure the rheological properties of the inks. All the measurements were performed at 25 °C. Each sample was equilibrated for 10 min before analysis. The values reported are averages of three replicates. To characterize linear viscoelastic and flow properties of the inks, flow analysis was performed between 0.01 and 500 s* for the inks at different PEDOT:PSS wt%, as shown in Fig. 2d, and at different solids content, as shown in Fig. 2a and 2c. To estimate the storage (black lines) and loss (white lines) modulus, time sweep measurements were performed, and the results are shown in Fig. 2b.

SEM and EDS measurements A Hitachi S-4800 Field-Emission Scanning Electron l\/licroscope equipped with energy- dispersive X-ray spectroscopy, EDS, detector was used for studying morphology and elemental mapping. The images of Figs.4a and 4b was obtained using this setup.

Wide Angle X-Ray Scattering (WAXS) A known technique for determining the degree of crystallinity of polymers, such as the PEDOT, is wide-angle X-ray scattering (WAXS). Wide-angle X-ray scattering 13 Psss4sEoo measurements were performed using an Anton Paar SAXSpoint 2.0 system (Anton Paar, Graz, Austria) equipped with a l\/licrosource X-ray source (Cu Koi radiation with a wavelength 0.15418 nm) and a Dectris 2D CMOS Eiger R 1l\/l detector. The sample-to- detector distance was 111 mm. The samples were mounted on a solid sampler (Anton Paar, Graz, Austria), mounted on a VarioStage (Anton Paar, Graz, Austria). The samples were placed under vacuum. For each sample, three frames each of 20 min duration were read from the detector. The data obtained using this setup is shown in Figs. 5a and 5b.

Contact angle measurements A contact angle meter (Theta lite, Biolin Scientific) was used to determine contact angle on the samples as shown in Figs. 6a and 6b Results Preparation of DALC-based inks.

As can be understood herein it has been shown that DALC-modified cellulose can be used as a bio-based alternative to typical polymers in printable, electrically conductive inks. Although the reason is not completely understood, some similarities to e.g. PVA may be found. For example, dialcohol modified fibers haves an abundance of polar hydroxyl groups available on their surfaces. PVA is earlier known to form interpenetrated networks with PEDOT:PSS, resulting in strong, stretchable, and flexible hydrogels that can be used in, for example, energy storage devices (Liu et al., 2021; Kara et al., 2014).

The inks prepared without plasticizer showed good processability but a lower conductivity. Also, the final material was not wet stable. Hence, the plasticizer increased the conductivity of PEDOT:PSS and also helped in imparting wet stability (the reason for which is not understood fully) to the DALC/PEDOT:PSS composite.

Figures 2a, 2b, 2c and 2d shows a rheology analysis of the DALC/PEDOT:PSS ink at different PEDOT:PSS wt% (20 wt%, 40 wt% and 70 wt%), as well as rheology analysis of the ink (PEDOT:PSS = 40 wt%) at different solids content (3-10 wt%). lnks at 6-10% solid content showed a clear shear thinning and shear yielding behavior, i.e. the ink requirements typically needed for printing. A lower solids content (1 -5 wt%) of ink is usually required for printing techniques such as blade coating, stencil printing, screen 14 P6334SE00 printing, slot-die coating or solution processing. The inks with solids contents of 6-8 wt% were used for 3D printing in the subsequent examples.

The inks showed a gel-like behavior at solids content above 3 wt%. Atomic force microscopy (AFl\/I) image of dry samples showed that PEDOT:PSS particles were organized on DALC surface in a pearl-necklace-like morphology, as seen in Figure 3. Hence, it can form an entangled network of PEDOT:PSS covered fibers providing a gel-like character.

Interaction between DALC fibers and PEDOT:PSS To assess the distribution of PEDOT:PSS in DALC/PEDOT:PSS composites, scanning electron microscopy (SEl\/l) images and sulfur mapping images of 3D-printed samples were collected. They showed a surface and layered cross-section, as shown in Figs. 4a and 4b, covered with PEDOT:PSS particles where individual fibers cannot be identified as the DALC fibers have film forming properties. Hence, good conductivity can be achieved owing to a homogeneous adsorption of PEDOT:PSS particles on both exterior and inner surfaces of the fibers due to the excellent film forming properties of DALC fibers.

An important factor for a good conductivity is removal of free PSS from PEDOT:PSS and thereby a better packing of PEDOT crystallites. As can be seen in Figs. 5a and 5b, WAXS showed an intense PSS peak that shifted from 1.3 Å* in pure PEDOT:PSS to 1.4 Å* in 3D printed films (d-spacing 0.51 nm to 0.44 nm), showing a reduction in stacking distance between PSS crystallites. However, the PEDOT 010 and the PEDOT 100 peak responsible for n-rr stacking of PEDOT crystallites are absent (Figure 5a). On the other hand, after washing of the 3D-printed films in water, these PEDOT peaks appeared, as well as significant concomitant reduced intensity of the PSS peak (Figure 5b). Furthermore, the PEDOT 010 peak typically assigned for edge-on orientation of PEDOT orystallitos, shifted from a q-valuo of 1.73 Å* in pure PEDOT:PSS to 1.82 Å* in 3D-printed samples, leading to a decreased stacking distance (from 0.36 nm to 0.34 nm). However, only a very weak PEDOT 100 peak, indicative of face-on orientation of PEDOT crystallites, appeared in the 3D-printed films. Therefore, based on WAXS, it can be suggested that DALC fibers are not only acting as a template for PEDOT:PSS particles but they are also inducing a PSS phase separation required for an increased conductivity in PEDOT:PSS (Ouyang et. Al., 2015). ln addition, close packing of Psss4sEoo PEDOT crystallites in edge-on orientation is favored, which has been shown to be responsible for high conductivity of PEDOT:PSS in previous studies (Bießmann et. al., 2019; Palumbiny et al., 2015). The analysis of morphology and x-ray scattering showed that DALC fibers may induce a similar crystallization in PEDOT:PSS as ethylene glycol or other secondary dopants.

Contact angle measurements, as shown in Figs. 6a and 6b, of the printed DALC/PEDOT:PSS films showed the increase in contact angle from 18 degrees for as printed and dried films to 121 degrees after washing these films. This shows that the surface changed from hydrophilic to hydrophobic due to enrichment in PEDOT. Whereas, in pure PEDOT:PSS/glycerol films, the contact angle changed from 14.5 degree to 38 degrees, which is indeed not as significant. lt implies that the surface is enriched with more PEDOT domains (as PEDOT is more hydrophobic) and PSS removal after washing. This effect is more apparent in DALC/PEDOT:PSS/glycerol samples than pure PEDOT:PSS/glycerol samples. Therefore, dialcohol cellulose is important to induce a larger phase separation of PEDOT:PSS.

Conclusion We have developed a promising conducting ink based on dialcohol-modified cellulose fibers and PEDOT:PSS that exhibits wet stability. DALC fibers acts as a template for PEDOT:PSS particles and helps in phase separation of PSS and PEDOT that leads to high conductivity in printed inks even with low content of PEDOT:PSS. The use of modified-cellulose-fibers also eliminates the need for cellulose nanofibrils, which has higher embedded energy, often used for bio-based electronics.

Example 2. Processing of inks and electrical characterization A direct-ink-writing 3D bio-printer was used to print different 2D and 3D patterns as shown in Figs. 7a - 7d. Although a 3D bio-printer is used, the inks can be printed with other printing techniques as well. These can also be processed using melt extrusion, solution processing techniques as well as paper making techniques.

Materials and methods An lnkredible 3D bio-printer (Cellink®) was used for printing. inks were transferred to a syringe, centrifuged for 30 s to remove any air bubbles introduced during mixing, and printed with high-precision conical nozzles (20G, 25G and 27G, Cellink®). The print 16 Psss4sEoo head speed and print pressure were manually adjusted for each ink composition. The printed samples were dried at 60 f-"C in oven overnight.

Electrical and Electrochemical measurements Two-probe conductivity test was performed using a Keithley 2410 source meter. Samples were cut in rectangles with dimensions of 2 cm >< 0.5 cm >< (thickness) and voltage was recorded at constant current. Resistance was calculated from the slope of the I-V curve. The following formula was used to calculate the conductivity: Rxwxt r>= L o=1/p where p is the resistivity, R is the resistance of the sample, w is the width, t is the thickness, L is the distance between two electrodes and o is the conductivity.

Cyclic voltametery and galvanostatic charge/discharge measurements were performed with a three electrode setup using BioLogic VSP potentiostat. The setup consisted of: Ag/AgCl (BASi®, 3l\/I NaCl) reference electrode, a platinum counter electrode and 3D printed sample mounted on a platinum wire as a working electrode; dipped in 1 M sulphuric acid as electrolyte. The open circuit potential was recorded before starting each measurement. The specific capacitance of the material was calculated from discharge cycle as follows: C = L m AV where, I is the discharge current, t is the discharge time, AV is the voltage window and m is the mass of PEDOT in the sample. l\/lass of PEDOT in the measured sample was calculated as follows: A rectangular piece (20 mm >< 5 mm) of 3D-printed DALC/PEDOT:PSS sample was weighed (IVIO) and then dipped in 1 M H2SO4 overnight and washed thoroughly with milli-q water afterwards. The sample was left to dry in ambient conditions and the mass of dried sample was again measured (lVlf). Since, the sample lost glycerol and some PSS present in the sample (the residual electrolyte was transparent after sample dipping), the final weight comprises of only cellulose fibers and PEDOT:PSS. l\/lass of cellulose and PEDOT:PSS in printed sample = lVlf l\/lass of PEDOT:PSS in the sample = 0.4 * lVlf, calculated based on initial ratio (DALC/PEDOT:PSS ) of the ink. 17 P6334SEOO Mass of PEDOT in the sample = à * (0.4*l\/lf), since the original ratio of PEDOT:PSS (as purchased) is 1:2.5 (neglecting the loss of PSS).

Results The 3D-printed gels had a conductivity of 30 i 3 S/cm. The conductivity increased with PEDOT:PSS content to level off at a PEDOT:PSS content of 40 wt%, as shown in Fig.8. This indicates a saturation threshold in 3D-printed samples, with a conductivity of ~10 S/cm even at 20 wt% PEDOT:PSS, which is good enough for bio-electronic applications. To the best of our knowledge, it is the first demonstration of such good conductivity values obtained for a 3D-printed, cellulose-fiber-based PEDOT:PSS ink where the conducting material only accounts for 20% of the total mass. Furthermore, the printed materials were stable in water and physiological solutions for at least 75 days without significant loss in conductivity, as seen in Fig. 9. A rapid conductivity drop in PBS in comparison to water could be attributed to de-doping of PEDOT:PSS in salt solution (Cho et al., 2018). The 3D-printed patterns are bendable, and elastic with conductivity retention of 99%, here demonstrated by a still glowing LED-light after stretching the printed serpentine pattern (Figure 10a and 10b).

Electrochemical performances To demonstrate the potential of our developed 3D-printable conducting inks in energy storage applications, we analyzed the electrochemical performance using a three- electrode setup (Figure 11). Cyclic voltametery (CV) for a material containing 40 wt% PEDOT:PSS showed an ideal supercapacitive behavior, maintaining a quasi- rectangular shape even at high scan rates of 100 mV/s (Figure 12), i.e. the typical response from electrical double-layer capacitor. The galvanostatic charge-discharge (GCD) curves are triangular in shape without significant potential drop (Figure 13), showing an efficient charge storage ability due to the high conductivity of the printed working electrode. The gravimetric discharge capacitance is as high as 197 F/g (normalized with PEDOT mass) and the areal capacitance is 170 mF/cm2 even at 10 A/g (Figure 14). The capacity normalized with respect to the mass of the entire electrode is listed in Table 1. As can be seen, 3D-printed samples are approaching the theoretical specific capacitance of 210 F/g (Snook et. al., 2011) for PEDOT, despite the fact that only 40% of 3D printable ink is PEDOT:PSS. The specific capacitance at current density of 1 A/g increases from 26 F/g to 211 F/g when the PEDOT:PSS content is increased from 20 wt% to 40 wt%, but then decreased to 158 F/g if the 18 Psss4sEoo PEDOT:PSS content was further increased to 70 wt% (Table 2), i.e. following the same trend as the conductivity values. Again showing that a good electrically conductive network is formed even at low PEDOT:PSS contents.

The ion transport and charge transfer kinetics were studied using electrochemical impedance spectroscopy (EIS) within a frequency range of 10 mHz to 1 I\/|Hz. Before initiating any charge/discharge cycling, the Nyquist plot (Figure 15) shows a small intercept on the real impedance axis in the high-frequency range, 0.7 Qxcmz, indicating that the printed electrode had a very low intrinsic resistance. The semicircle at the high- to-medium frequency range indicates charge-transfer resistance. The semicircle disappears after 10 000 charge-discharge cycles, indicating that the charge transfer at the electrode/electrolyte interface is improved during the cycling. This good charge transfer is also the reason why an increased (from 230 to 280 F/g) capacitance was observed after 10 000 cycles (Figure 16).

Table 1. Specific capacitance and current density values calculated by considering different active mass components Active mass components Specific Capacitance (F/g) Current density (A/g) PEDOT 211 1 PEDOT:PSS 61 0.3 PEDOT:PSS+DALC+glycerol 30 0.1 Table 2. Specific capacitance values for 3D printed samples with different PEDOT:PSS content at 1A/g PEDOT:PSS content (by weight) Specific Capacitance (F/g) 20 26 40 211 70 158 Conclusion 3D printed samples show comparable electrochemical performance as state of the art bio-based PEDOT:PSS supercapacitors that either use secondary doping such as acid treatment for doping PEDOT:PSS or a mixture of PEDOT:PSS and other redox active molecules. 19 Psss4sEoo The vertical tails of the Nyquist plots (Figure 15) in the low-frequency range suggest the diffusive resistance of the electrode is very low, benefitting from the gel-like electrode structure.

Example 3. Wearable bio-electronic devices Materials and methods For electrical and electrochemicai measurements please refer to l\/laterials and methods in Example 2.

EC-12 tests and ECG and EMG measurements EC-12 tests were performed at Beneli AB, Sweden in gel-gel configuration using SEAM ECG Electrode Test Platform (QC Integrated, Ontario, Canada).

To perform the ECG recordings, a reference electrode was placed on the abdomen of a person and then one electrode (either gel or printed PEDOT) on each of the person's index fingers. To record the activity generated by the opening and closing of the hand, a reference electrode was placed on the elbow and two printed PEDOT electrodes were placed on opposite sides of the forearm. The signals produced by the hand signs were recorded using the same configuration and adding a third electrode in between the other two. The electrical signals were registered using a RHD2132 amplifier (INTAN Technologies, USA) on a custom PCB board. The output of the amplifier was connected to an integration module containing a Spartan-6 FPGA (model XEl\/l6010- LX45, Opal Kelly lnc., USA) from which it was collected by a laptop via a USB connection using the BHX Data Acquisition Software (lntan Technologies, USA). The signals were recorded at a rate of 20kS/s using different frequency ranges on each case: 1 to 100Hz for ECG and 0.1 to 1kHz for EMG. The acquired digital signals were processed offline with the aid of Python programming.

The power line interference on the signals was removed by applying second-order llR digital filters with stop frequencies at 50, 100, 150, 200, 300 and 400Hz. Fourth-order high- and low-pass Butten/vorth filters were applied at 1kHz and 1Hz respectively to restrict the signals to the desired frequency bands. The P-QFlS-T complexes on the ECG signal were detected as the 1s windows around peaks with a height larger than 5 times the standard deviation of the signal. For the hand-sign EMG monitoring, first the signals from all three electrodes were merged to detect windows of events. The Psss4sEoo merged signal was squared, smoothed using a running average with a window of 1000 samples and normalized. The 1-sample differential was calculated on the smoothed, normalized signal. A threshold of 0.07 was used on the differential to distinguish windows of events with EMG activity from the background. On each event-window we then computed the power of the signal of each electrode and normalized it by the power of the added signals.

Results Owing to the stretchability, flexibility and good electrochemical behavior of the 3D- printed electrodes, it was possible to fabricate a supercapacitor device by tvvisting two extruded filaments coated with gel electrolyte (Figure 17). The two-electrode device shows a discharge capacitance of 123 F/g and a good cyclability at 3 A/g (Figure 18), demonstrating a potential where extruded fibers can be weaved as a textile, for wearable energy storage devices.

Furthermore, to assess the potential of 3D printed electrodes in electrocardiography (ECG) monitoring, we performed (ANSl:AA|\/l| EC12:2000) standard tests for disposable ECG electrodes in electrode-electrode configuration. Different parameters measured for three different PEDOT:PSS contents are summarized in Table 3a and b. Besides default parameters such as AC impedance, DC offset voltage and noise, defibrillation discharge was measured, which determines the electrode's ability to measure ECG after a defibrillation event. To read more about the measured parameters and their role in ECG monitoring please refer to a study by Zalar et. al., 2020.

As can be seen from Table 3, even with as little as 20 wt% of PEDOT:PSS, the AC impedance, the noise level and the defibrillation discharge had better values than recommended by the standard. To further test and demonstrate the material's applicability in ECG monitoring devices, we tested 3D-printed electrodes to record ECG signals. A standard 3-lead ECG shows good ECG signal with clear P-QRS peaks (Figure 19a and Figure 19b). 21 Psss4sE00 Table 3a: EC-12 test results for 3D printed electrodes Dimensions I Measurement AC |rnpedance DC offset of electrodes References Pararneters (Q) voltage (mV) (mm) Standard ANSI/AAMI EC12- <10 KQ <100 Tsukada et al., 2019 2000 PEooTPss/DALC (20/80) 17><7 28.8 i 5.0 0.4 i 0.2 This Work PEooTPss/DALC (40/60) 17><7 34.5 i 11.0 0.4 i 0.3 This Work PEooTPss/DALC (70/30) 17><7 32.8 i 8.0 0.4 i 0.3 This Work Ag/Agci with 18x35 33 KQ - Tsukada et al., 2012 adhesive gel PEDOTIPSS silk 7><12 0.2 KQ - Tsukada et al., 2012 glycerol thread Hitoe® electrode (polyester nanofibre yarn with PEDOT:PSS) 40x80 1.26i0.18 KQ - Tsukada et al., 2019 lmrnersed in NaCl and glycerol solution before mGaSUFGmGITE 22 Psss4sEoo Table 3b: EC-12 test results for 3D printed electrodes Defibrillation DC offset Internal discharge at Measurement voltage after Noise 100 mV References Parameters test (uV) (5/15/25/35) (mV) (mV) Standard ANSI/AAMI Tsukada et al., <150 <100 <100 EC12-2000 2019 PEDOT:PSS/DALC(20/80) 52.0 i 6.0 0.4 i 0.2 0.1 This work PEDOT:PSS/DALC(40/60) 38.0 i 7.0 0.5 i 0.4 0.2 i 0.1 This work PEDOT:PSS/DALC 55.2 i I 0.6 i 0.3 0.4 i 0.3 This work (70/30) 10.0 Tsukada et al., Ag/AgCl with adhesive gel - - - 2012 PEDOT:PSS silk glycerol Tsukada et al., thread 2012 Hitoe® electrode (polyester nanofibre yarn with PEDOT:PSS) Tsukada et al., 1-3 - 0.0028i0.0020 lmmersed in NaCl and 2019 glycerol solution before measurement Conclusion The conducting polymer ink showed good electrochemical performance in energy storage as well as body potential monitoring devices. This work paves a way forward to fabricate greener bioelectronics by using bio-based, high performance conducting ink and enables a step in the direction of green devices. Hence, the reduced need for cellulose nanofibrils, a low weight fraction of conducting polymer in 3D ink along with good processability and excellent properties provides scalable and affordable fabrication of fiber-based wearable electronics. 23 Psss4sEoo Example 4. Printed Microelectrode-arrav (MEA) devices The inks developed herein can be used to measure and monitor potentials from different types of cells such as cardiomyocytes or neural cells. They can be cheaper than gold-based MEAs commercially available and also do not require patterning techniques for cleanroom fabrication of such devices. Hence, saving the cost as well as time for fabrication process of MEAs.

References M. Bengtsson, M. Le Baillif, K. Oksman, Compos. Part A Appl. Sci. Manuf. 38 (2007) 1922-1931.

Bießmann, L. et al. Highly Conducting, Transparent PEDOT:PSS Polymer Electrodes from Post-Treatment with Weak and Strong Acids. Advanced Electronic Materials 5, 1800654 (2019).

Cho, H., Cho, W., Kim, Y., Lee, J. & Hyun Kim, J. Influence of residual sodium ions on the structure and properties of poly(3,4- ethylenedioxythiophene):poly(styrenesulfonate). HSC Advances 8, 29044-29050 (2018).

Kara, M. O. P. & Frey, M. W. Effects of solvents on the morphology and conductivity of poly(3,4-ethylenedioxythiophene):Poly(styrenesulfonate) nanofibers. Journal of Applied Polymer Science 131, (2014).

Larsson, P. A. & Wàgberg, L. Towards natural-fibre-based thermoplastic films produced by conventional papermaking. Green Chem. 18, 3324-3333 (2016).

Liu, Q. et al. High-Performance PVA/PEDOT:PSS Hydrogel Electrode for All-Gel-State Flexible Supercapacitors. Advanced Materials Technologies 6, 2000919 (2021).

Ouyang, L., Musumeci, C., Jafari, M. J., Ederth, T. & lnganäs, O. Imaging the Phase Separation Between PEDOT and Polyelectrolytes During Processing of Highly Conductive PEDOT:PSS Films. ACS Appl. Mater. lnterfaces 7, 19764-19773 (2015). 24 Psss4sEoo Palumbiny, C. l\/l. et al. The Crystallization of PEDOT:PSS Polymeric Electrodes Probed ln Situ during Printing. Advanced Materials 27, 3391-3397 (2015).

Snook, G. A., Kao, P. & Best, A. S. Conducting-polymer-based supercapacitor devices and electrodes. Journal of Power Sources 196, 1-12 (2011).

Tsukada, Y. T. et al. Validation of wearable textile electrodes for ECG monitoring. Heart Vessels 34, 1203-1211 (2019).

Tsukada, S., Nakashima, H. & Torimitsu, K. Conductive Polymer Combined Silk Fiber Bundle for Bioelectrical Signal Recording. PLOS ONE 7, e33689 (2012).

Zalar, P., Saalmink, M., Flaiteri, D., Brand, J. van den & Smits, E. C. P. Screen-Printed Dry Electrodes: Basic Characterization and Benchmarking. Advanced Engineering Materials 22, 2000714 (2020).

Items 1. A composition comprising, (a) a dialcohol cellulose; and (b) an electrically active material 2. The composition according to item 1, further comprising a plasticizer. 3. The composition according to any one of the preceding items, wherein the composition comprises between 5 wt% and 70 wt% of the electrically active material. 4. The composition according to any one of the preceding items, wherein the composition comprises between 30 wt% and 95 wt% of the dialcohol cellulose.

. The composition according to any one of items 2 - 4, wherein the composition comprises between 10 wt% and 80 wt% of the plasticizer. 6. The composition according to any one of the preceding items, wherein the composition has an electric conductivity of at least 0.05 S/cm, such is at least 0.1 S/cm, such as at least 0.5 S/cm, such as at least 1 S/cm.

Psss4sEoo 7. The composition according to any one of the preceding items, wherein the dialcohol cellulose comprises fibers having a diameter of at least 1 pm, such as at least 5 pm, such as at least 8 pm, such as at least 12 pm. 8. The composition according to any one of the preceding items, wherein the dialcohol cellulose comprises nanofibrils having a diameter of less than 1000 nm, preferably less than 500 nm, or less than 200 nm, or less than 100 nm, or 50 nm. 9. The composition according to any one of items 2 - 8, wherein the plasticizer comprises a polyol.

. The composition according to item 9, wherein the polyol is selected from the group consisting of a glycerol, a sorbitol and an erythritol. 11. The composition according to any one of items 9 - 10, wherein the polyol comprises glycerol. 12. The composition according to any one of items 2 - 11, wherein the plasticizer comprises DMSO. 13. The composition according to any one of items 2 - 12, wherein the plasticizer comprises ionic liquids. 14. The composition according to any of one of the preceding items, wherein the electrically active material comprises an electrically conducting polymer.

. The composition according item 14, wherein the electrically conducting polymer comprises one or more polymers selected from the group consisting of polyphenylenes, polypyrenes, polyazulenes, polynaphthalenes, polyacetylenes (PAC), poly-p-phenylene vinylene (PPV), polypyrroles (PPY), polyazepines, polyanilines (PANl), polythiophenes (PT), poly-3,4-ethylenedioxythiophene (PEDOT), toluenesulfonyl (Tos) and a polystyrene sulfonates (PSS). 26 Psss4sEoo 16. The composition according to any one of items 14 - 15, wherein the electrically conducting polymer comprises PEDOT:PSS. 17. The composition according to any one of the preceding items, wherein the composition comprises between 10 wt% and 50 wt% of the electrically conducting polymer. 18. The composition according to any one of the preceding items, wherein the composition comprises 40 wt% of the electrically conducting polymer. 19. The composition according to any according to any one of the preceding items, wherein the electrically active material comprises an electrically conducting carbon.

. The composition according to item 19, wherein the electrically conducting carbon is selected from the group consisting of 1D carbons, 2D carbons and 3D carbons. 21. The composition according to item 20, wherein the 3D carbon is a graphite. 22. The composition according to item 20, wherein the 2D carbon is a graphene. 23. The composition according to item 20, wherein the 1D carbon is a carbon nanotube. 24. The composition according to any one of the preceding items, wherein the electrically active material comprises an electrically conducting 2D material.

. The composition according to item 24, wherein the electrically conducting 2D material is selected from the group consisting of a graphene, a MXenes and a Molybdenum disulfide (MoSz). 26. An electrically conductive material comprising the composition according to any one of the preceding items. 27. The electrically conductive material according to item 26, wherein the composition has been applied by 3D-printing, 2D-printing, screen printing, stencil printing, blade- 27 Psss4sEoo coating, melt-processing, molding, slot die coating, inkjet printing, laser printing, solution processing, vacuum filtration, solvent casting and/or paper making techniques. 28. The electrically conductive material according to any one of items 26 - 27, wherein the composition is at least partly dried before, during and/or after applying the composition. 29. The electrically conductive material according to any one of items 26 - 27, wherein the composition is at least partly cured before, during and/or after applying the composition.

. The electrically conductive material according to items 26 - 29, wherein the composition further comprises a cross-linking agent. 31. The electrically conductive material according to item 30, wherein the cross-linking agent is added before, during and/or after applying the composition. 32. The electrically conductive material according to any one of items 30 - 31, wherein the cross-linking agent is selected from the group consisting of ionic cross-linkers, photo cross-linkers and covalent cross-linkers. 33. The electrically conductive material according to any one of items 26 - 32, wherein the material has a conductivity of at least 0.05 S/cm, such is at least 0.1 S/cm, such as at least 0.5 S/cm, such as at least 1 S/cm. 34. A method of manufacturing an electrically conductive material comprising a step of applying the composition according to any one of items 1 - 25, thus obtaining said electrically conductive material.

. The method of manufacturing according to item 34, wherein applying the composition comprises 3D-printing, 2D-printing, screen printing, stencil printing, blade- coating, melt-processing molding, slot die coating, inkjet printing, laser printing, solution processing, vacuum filtration, solvent casting and/or paper making techniques. 28 Psss4sEoo 36. The method according to any one of items 34 - 35, wherein the composition is at least partly dried before, during and/or after applying the composition. 37. The method according to any one of items 34 - 35, wherein the composition is at least partly cured before, during and/or after applying the composition. 38. The method according to any one of items 34 - 37, wherein the method further comprises (an) additional step(s) of adding a cross-linking agent before, during and/or after applying the composition. 39. A device manufactured with the electrically conductive material according to any one of the items 26 - 33. 40. The device according to item 39, wherein the device is selected from the group consisting of an electronic device, an energy storage device, a sensor, an electrode, and an automotive device. 41. A use of the electrically conductive material according to any one of items 26 - 33 in an electronic device. 42. A use of the electrically conductive material according to any one of items 26 - 33 in an energy storage device. 43. A use of the electrically conductive material according to any one of items 26 - 33 in a sensor. 44. A use of the electrically conductive material according to any one of items 26 - 33 in an electrode. 45. A use of the electrically conductive material according to any one of items 26 - 33 in an automotive device. 46. A method of manufacturing the composition according to any one of the items 1 - 25, the method comprising a step of mixing a dialcohol cellulose with an electrically active material, thus obtaining the composition. 29 Psss4sEoo 47. The method of manufacturing according to item 46, further comprising a subsequent step wherein the plasticizer according to any one of items 2, 5, 9 - 13 is mixed in with the dia|coho| cellulose and the e|ectrica||y active material.

Claims (10)

Claims 1 _

1.A composition comprising, (a) a dialcohol cellulose; (b) and an electrically active material, wherein the composition comprises between 5 wt% and 70 wt% of the electrically active material, and wherein an electrically active material comprises an electrically conducting polymer.

2.The composition according to claim 1, further comprising a plasticizer.

3.The composition according to any one of the preceding claims, wherein the composition comprises between 30 wt% and 95 wt% of the dialcohol cellulose.

4.The composition according to any one of claims 2 - 3, wherein the composition comprises between 10 wt% and 80 wt% of the plasticizer.

5.The composition according to any one of claims 2 - 4, wherein the plasticizer comprises glycerol.

6.The composition according to any one of the preceding claims, wherein the dialcohol cellulose comprises fibers having a diameter of at least 1 um, such as at least 5 um, such as at least 8 um, such as at least 12 um.

7.The composition according to any one of the preceding claims, wherein the electrically conducting polymer comprises PEDOT:PSS.

8.The composition according to any one of the preceding claims, wherein the composition comprises 40 wt% of the electrically conducting polymer.

9.An electrically conductive material comprising the composition according to any one of the preceding claims, wherein the composition has been applied by 3D- printing, 2D-printing, screen printing, stencil printing, blade-coating, melt- processing, molding, slot die coating, inkjet printing, laser printing, solution processing, vacuum filtration, solvent casting and/or paper making techniques. 31 Psss4sEoo

10. The electrically conductive material according to claim 9, wherein the composition further comprises a cross-linking agent.