Method of producing electrically conductive polymer and cellulose nanocomposites

Abstract

A method is provided for preparing electrically conductive polymer and cellulose nanocomposite particles and nanocomposite materials. Cellulose microparticles coated with a conductive polymer are added to an acid solution for initiating an acid hydrolysis reaction for a prescribed time interval to form conductive polymer coated cellulose nanoparticles. After quenching the acid hydrolysis reaction, the nanoparticles are separated to obtain a colloidal solution of conductive nanoparticles. The conductive nanoparticles may be subsequently formed into a solid nanocomposite material such as a conductive film. Transparent conductive films may be prepared by forming thin layers having a thickness on a micron or submicron scale.

1 - 54 . (canceled) 
     
     
         55 . An electrically conductive nanocomposite coating composition comprising an aqueous colloidal solution of cellulose nanoparticles that are coated with a conductive polymer. 
     
     
         56 . The nanocomposite coating composition according to  claim 55  wherein said conductive polymer is polypyrrole. 
     
     
         57 . The nanocomposite coating composition according to  claim 55  wherein said conductive polymer is selected from the group consisting of: polyaniline, polyindole, polythiophene, poly(3-methylthiophene), poly(N-methyl aniline), and poly(o-toluidine). 
     
     
         58 . The nanocomposite coating composition according to  claim 55  wherein the cellulose nanoparticles are nanocrystalline cellulose particles. 
     
     
         59 . An electrically conductive nanocomposite coating layer comprising cellulose nanoparticles that are coated with a conductive polymer. 
     
     
         60 . The electrically conductive nanocomposite coating layer according to  claim 59  wherein said conductive polymer is polypyrrole. 
     
     
         61 . The electrically conductive nanocomposite coating layer according to  claim 59  wherein said conductive polymer is selected from the group consisting of: polyaniline, polyindole, polythiophene, poly(3-methylthiophene), poly(N-methyl aniline), and poly(o-toluidine). 
     
     
         62 . The electrically conductive nanocomposite coating layer according to  claim 59  wherein said cellulose nanoparticles are nanocrystalline cellulose particles. 
     
     
         63 . The electrically conductive nanocomposite coating layer according to  claim 59  having a thickness such that said nanocomposite coating layer is optically transmissive. 
     
     
         64 . The electrically conductive nanocomposite coating layer according to  claim 63  wherein a peak optical transmittance is at least 50% within the visible spectrum. 
     
     
         65 . The electrically conductive nanocomposite coating layer according to  claim 59  wherein a volume resistivity of said coating layer is between approximately 10̂7 Ohm-cm and 10̂11 Ohm-cm. 
     
     
         66 . The electrically conductive nanocomposite coating layer according to  claim 59  wherein a volume resistivity of said coating layer is between approximately 10̂7 Ohm-cm and 10̂8 Ohm-cm. 
     
     
         67 . The electrically conductive nanocomposite coating layer according to  claim 59  wherein a conductivity of said coating layer is approximately 10̂−2 S/cm. 
     
     
         68 . The electrically conductive nanocomposite coating layer according to  claim 59  wherein a surface resistivity of said coating layer is approximately 10̂5 Ohm/sq. 
     
     
         69 . A nanocomposite electrode comprising:
 a substrate; and   an electrically conductive nanocomposite coating layer formed on said substrate, wherein said electrically conductive nanocomposite coating layer is provided according to  claim 59 .   
     
     
         70 . A biosensor comprising a nanocomposite electrode according to  claim 69 , wherein said electrically conductive nanocomposite coating layer is functionalized for the attachment of a biological recognition or signal generating moiety. 
     
     
         71 . A battery comprising at least one nanocomposite electrode according to  claim 69 . 
     
     
         72 . The battery according to  claim 71  comprising two nanocomposite electrodes, wherein one of said nanocomposite electrodes is doped. 
     
     
         73 . An article coated with an electrically conductive nanocomposite coating layer according to  claim 59 . 
     
     
         74 . An electrostatic discharge packaging material comprising an electrically conductive nanocomposite coating layer according to  claim 59 . 
     
     
         75 . A method of preparing an electrically conducting nanocomposite material, the method comprising the steps of:
 providing cellulose microparticles coated with a conductive polymer;   adding the microparticles to an acid solution for initiating an acid hydrolysis reaction;   reacting the microparticles with the acid to form nanoparticles comprising the conductive polymer and the cellulose;   quenching the acid hydrolysis reaction; and   separating the nanoparticles from the acid solution to obtain a colloidal solution of the nanoparticles.   
     
     
         76 . The method according to  claim 75  further comprising:
 pouring the colloidal solution onto a solid surface; and 
 drying the colloidal solution to obtain a nanocomposite layer. 
 
     
     
         77 . The method according to  claim 76  further comprising removing the nanocomposite layer, so that the nanocomposite layer is free-standing. 
     
     
         78 . The method according to  claim 76  wherein the nanocomposite layer has a thickness suitable for optical transmission. 
     
     
         79 . The method according to  claim 76  wherein the nanocomposite layer has a thickness on a micron scale. 
     
     
         80 . The method according to  claim 76  wherein the nanocomposite layer has a thickness on a submicron scale. 
     
     
         81 . The method according to  claim 75  wherein the conductive polymer is polypyrrole. 
     
     
         82 . The method according to  claim 75  wherein the conductive polymer is selected from the group consisting of polyaniline, polyindole, polythiophene, poly(3-methylthiophene), poly(N-methyl aniline), and poly(o-toluidine). 
     
     
         83 . The method according to  claim 75  wherein the step of reacting the microparticles with the acid is performed for a time duration such that an average diameter of the nanoparticles is between about 30 and 50 nanometers, and an average length of the nanoparticles is between about 300 and 500 nanometers. 
     
     
         84 . The method according to  claim 75  wherein the microparticles comprise microcrystalline cellulose. 
     
     
         85 . The method according to  claim 75  wherein the step of providing the microparticles comprising cellulose coated with a conductive polymer is performed by:
 forming a mixture comprising cellulose microparticles, a monomer and a surfactant; 
 agitating the mixture to disperse the microparticles and to obtain cellulose microparticles coated with the monomer; 
 initiating a polymerization reaction to obtain cellulose microparticles coated with a conductive polymer; and 
 allowing the polymerization reaction to proceed for a prescribed time interval. 
 
     
     
         86 . The method according to  claim 85  wherein the step of initiating the polymerization reaction comprises adding an oxidant to the mixture, thereby initiating a polymerization reaction to form cellulose microparticles coated with the conductive polymer. 
     
     
         87 . The method according to  claim 86  wherein the oxidant is selected from the group consisting of iron (III) chloride hexahydrate, ferric chloride, ammonium persulphate, potassium persulphate, and phosphomolybdic acid hydrate. 
     
     
         88 . The method according to  claim 85  wherein the microparticles have a mean diameter between about 20 micrometers and about 25 micrometers and a length between about 40 and 60 micrometers. 
     
     
         89 . The method according to  claim 85  wherein the microparticles comprise fibers having a mean diameter on a micron scale and a length ranging from a micron scale to centimetre scale. 
     
     
         90 . The method according to  claim 85  wherein the microparticles comprise fibers comprising crystalline structures and amorphous structures. 
     
     
         91 . The method according to  claim 85  wherein prior to the step of initiating the polymerization reaction, the following steps are performed:
 separating the cellulose microparticles coated with the monomer from the mixture; and 
 rinsing the cellulose microparticles coated with the monomer in a solution of the monomer. 
 
     
     
         92 . The method according to  claim 75  wherein the cellulose microparticles coated with the conductive polymer are washed prior to the step of adding the microparticles to the acid solution. 
     
     
         93 . The method according to  claim 75  wherein the microparticles are washed in a dopant solution comprising a dopant prior to the step of adding the microparticles to an acid solution. 
     
     
         94 . The method according to  claim 93  wherein the dopant is one of chloride and sulphate. 
     
     
         95 . The method according to  claim 93  wherein the dopant is chloride and the dopant solution is hydrochloric acid. 
     
     
         96 . The method according to  claim 85  wherein said surfactant is selected from the group consisting of: sulfonic naphthalene acid, anthrquinone-2-sulfonic acid, tween-80, naphtalene sulfonic acid, p-dodecylbenzenesulfonic acid, cetyl trimethylammonium bromide, sodium dodecyl sulphate, cetyltrimethylammonium bromide and tritonX-100, alkyl sulfonates, and alkyl aryl sulfonate.