Title of Invention	"A SIMPLE ROUTE TO PREPARE EMERALDINE BASE NANOPARTICLES"
Abstract	The invention relates to a technique for producing emeraldine base nanoparticles wherein predetermined volumes of aniline and oxidant solutions in aqueous inorganic acid is maintained at a predetermined temperature. Predetermined volume of the oxidant solution is gently poured into the equal volume of aniline solution. The reaction mixture is kept undisturbed at predetermined temperature for overnight. The emeraldine salt is separated over a Buckner funnel and dedoped by excess of predetermined dedoping agent followed by washing with double distilled water and drying at 60°C in air oven for 2 days.

Title of Invention

"A SIMPLE ROUTE TO PREPARE EMERALDINE BASE NANOPARTICLES"

Abstract

The invention relates to a technique for producing emeraldine base nanoparticles wherein predetermined volumes of aniline and oxidant solutions in aqueous inorganic acid is maintained at a predetermined temperature. Predetermined volume of the oxidant solution is gently poured into the equal volume of aniline solution. The reaction mixture is kept undisturbed at predetermined temperature for overnight. The emeraldine salt is separated over a Buckner funnel and dedoped by excess of predetermined dedoping agent followed by washing with double distilled water and drying at 60°C in air oven for 2 days.

Full Text	The following specification particularly describes and ascertains the nature of this invention and the manner in which it is to be performed. The present invention relates to a procedure of "a simple route to prepare emeraldine base nanoparticles" BACKGROUND: Polymers due to their low electrical conductivity were mainly used as insulating materials. A breakthrough came with the in 1977 when MacDiarmid, Heeger, and Shirakawa discovered that exposure of conjugated polymer polyacetylene to iodine vapor yielded an electrically conducting material. Although their polyacetylene exhibits good electrical properties, its application is limited because of its poor stability in air and complicated synthesis methods. They were later awarded Nobel Prize in 2000. Since then, research in the field of conducting polymers was intensified searching for newer cheaper and smarter conducting polymer. During the meantime many such polymers were discovered such as polyaniline (PAni), polypyrrole (PPy), polythiophene (PTh) etc. These polymers have gained significant prominence recently because of their stability in air and optical and electrical properties. Polyaniline is unique among the family of conjugated polymers and has attracted considerable attention due to its low cost, simple synthesis, good environmental stability, simple nonredox doping/dedoping chemistry based in acid/base reactions, and favorable optical and electrical properties. It has found potential applications in electronic and optical devices such as batteries, artificial muscles, electromagnetic shielding devices, corrosion protection coatings, sensors, capacitors, hydrogen storage, fuel cells etc. Polyaniline was originally known in 1835 as "aniline black", a term used for any product obtained by the oxidation of aniline. Conducting properties of polyaniline were rediscovered in the early 1980s and PAni was found to have wide ranging application in various fields. Polyaniline can be synthesized by both the electrochemical and chemical oxidative polymerization in acidic, mildly acidic and even neutral media. However, the results are very different in each situation. This may be well understood from the opinion of Prof. A.G. MacDiarmid that "there are as many different types polyaniline as there are people who synthesize it". The conducting form of polyaniline is termed as emeraldine salt whereas the nonconducting form as emeraldine base. In recent past, the research on polyaniline and its derivatives was mainly focused on making it more processible and commercially available. It has experienced a great leap with the advent of nanoscience and nanotechnology in recent years. Synthesizing nanostructures of this unique conducting polymer has attracted special attention these days. The hope is that nanostructured polyaniline will offer better performance or new properties compared with its conventional bulk counterpart. Various research groups have conducted works involving synthesis of polyaniline nanofibers and nanoparticles. Few of these reports may be summarized as follows: F. Yan and G. Xue prepared nanoscopic polyaniline particles in a stable water-oil microemulsion using sodium dodecylbenzenesulfonate (SDBA) which acts as surfactant as well as dopant in the acidic reaction media. J. Mater. Chem. 9,3035-3039 (1999). Kim et. al. prepared polyaniline (PAni) dispersions consisting of 10-20 nm sized nanoparticles by oxidation with ammonium peroxydisulfate (APS) in sodium dodecylsulfate (SDS) micellar solutions. Synthetic Metals 122,297-304 (2001). Han et. al. carried chemical oxidative polymerization of aniline in micellar solution of dodecylbenzenesulphonic acid (DBSA, anionic surfactant) to obtain conductive polyaniline nanoparticles. Synthetic Metals 126, 53-60 (2002). Cho et. al. obtained nano-sized polyaniline (PAni) particles dispersed in aqueous solution using both poly(vinyl alcohol) (PVA) and poly(styrene sulfonic acid) (PSSA) as polymeric stabilizers. Material Science & Engineering C24,15-18 (2004). Park et. al. synthesized monodispersed polyaniline nanoparticles by oxidative dispersion polymerization using poly(sodium-4-styrenesulfonate) (PSSA) as both a polymeric stabilizer and a doping agent due to its acidity. Current Applied Physics 4,581-583 (2004). J. Huang and R. B. Kaner discussed mechanistic approach of nanofiber formation in the chemical polymerization of aniline. Angew. Chem. Int. Ed. 43, 5817 -5821 (2004). J. Huang and R. B. Kaner obtained uniform polyaniline nanofibers readily formed using interfacial polymerization without using templates or functional dopants. J. Am. Chem. Soc. 126,851-855 (2004). S. Dorey et.al. reported the synthesis of polyaniline (PAni) suspension of particles with size of about 2-3 nm. This nano-colloid was obtained by the oxidative polymerization aniline in dilute and semi-dilute solutions of sodium poly(styrenesulfonate). Polymer 46, 1309-1315, (2005). Cholli et. al. used biocatalytic approach to prepare polyaniline nanoparticles, however, they obtained it as a composite followed by separation of PAni nanoparticles from these composites. IUPAC Pure & Applied Chemistry 97,339-344 (2005). Li et. al. synthesized polyaniline submicrometer-sized tubes with controllable morphology by chemical oxidative polymerization of aniline with the aid of sodium dodecylbenzenesulfonate. J. Nano Res. 8,1039-1044 (2006). Jing et. al. used the conventional oxidation route to prepare polyaniline nanoparticles but used ultrasonic irradiation instead of mechanical mixing to obtain more uniform nanostructures. Ultrasonics Sonochemistry 14,75-50 (2007). Chen et. al. prepared a series of polyaniline (PAni) nanostructures from fiber to star-like, net-like and coral ball like by controlling the synthesis conditions such as monomer/stabilizer ratio, pH and reagent adding method and rate by diffusion polymerization. C. R. Chimie 11,84-89 (2008). Ganeshan et. al. prepared polyaniline nanoparticles with size ranging from 20 nm to 40 nm by the pulsed sonoelectrochemical method. Synthetic Metals 158, 848-853 (2008). Tran et. al. presented a bulk and template-free method to synthesize nanofibers of substituted polyanilines. Macromolecules 41,7405-7410 (2008). Xingwei Li et. al. obtained stabilizer-free polyaniline nanofiber aqueous colloids by the direct dispersion of polyaniline nanofibers prepared in presence of P-cyclodextrin. Materials Letters 62,1431-1434 (2008). Xing et. al. prepared polyaniline (PAni) nanofibers via interfacial polymerization method. In this method, aniline dissolved in xylene that is immiscible in water, was directly added into the aqueous solution of the oxidant under stirring. The polymerization was carried out at the interface formed between the organic liquid drops and the aqueous solution. Synthetic Metals 158,59-63 (2008). I. Sapurina and J. Stejskal discussed the mechanism of the oxidative polymerization of aniline and the formation of supramolecular polyaniline structures. Polym. Int. 57,1295-1325 (2008). Han et. al. prepared organic solvent dispersible dodecylbenzenesulfonic acid doped polyaniline (PAni) from DBSA micelles and with ammonium persulfate (APS) as an oxidant in hexane by one-step polymerization. Synthetic Metals 159,123-131 (2009). Rahy et. al. reported that nano-emulsions can be creatively used as a morphology selective synthesis method to prepare not only nano-grains but also nano-fibers with high selectivity. Polym. Adv. Technol (2009) DOI: 10.1002/pat.l562. Liu et. al. carried out the chemical oxidative polymerization of aniline on solid substrates treated with Au nanoparticles (Au-NPs) deposition and 4-aminothiophenol (ATP) modification. Polyaniline (PAni) fibers were obtained in micro-/nano-size with two-dimensional network structures. Synthetic Metals 159,1077-1081 (2009). Zhang et. al. presented a new approach for the synthesis of polyaniline nanofibers under pseudo-high dilute conditions in aqueous system. Synthetic Metals 159,1508-1511 (2009). Zhang et. al. prepared highly crystalline polyaniline (PAni) nanofibers with 16-23 nm in diameter by using FeCl3•6H2O as the oxidant in the presence of inorganic acids without any external template. Materials Chemistry and Physics 115,275-279 (2009). Fei et. al. basically used template guided method to prepare cubic and spherical nanostructures of polyaniline. ACS Nano 3,3714-3718 (2009). Li et. al. discussed various aspects of preparation and applications of polyaniline nanostructures. Ace. of Chem. Res. 42,135-145 (2009). Li et. al. synthesized high quality polyaniline nanofibers by a rapid polymerization of aniline using ammonium peroxydisulfate (APS)/Fe2+ redox initiator as the oxidant without any hard or soft templates. Polymer 51,1934-1939 (2010). Majority of work reported till date is not as simple as we are presenting here. The complex chemistry of polyaniline formation once again proved that there are lots more to do. To the first concern, we are here with a very simple route to prepare emeraldine base nanoparticles. The procedure is simple and discussed below: 1. Prepare the solutions of aniline and oxidant in aqueous solution of an inorganic acid. 2. Cool these solutions at a predetermined temperature. 3. Pour the oxidant solution into the aniline solution and keep it undisturbed for overnight at the predetermined temperature. 4. Separate polyaniline by filtration with a Buckner funnel. 5. Convert green emeraldine salt into emeraldine base nanopowder by dedoping by a predetermined dedoping agent. The nanopowder was analyzed for FT1R (Figure-1) and TEM (Figure-2). Moreover, a flow diagram of complete procedure is given in Figure-3. We Claim, 1. A technique for the production of polyaniline nanoparticles comprising following steps: a). Acidic aqueous solution of aniline of predetermined concentration is made. b). Acidic aqueous solution of potassium persulphate of predetermined concentration is also made. c). The two solutions were allowed to cool at a predetermined temperature. d). Predetermined volume of potassium persulphate solutions is gently poured into the equal volume of the aniline solution in glass beaker and kept at the predetermined temperature for overnight (normally more than 14-15 hours). The polymer so obtained was filtered, washed with distilled water, dedoped with excess of predetermined dedoping agent followed by washing with distilled water and dried in air oven. 2. A technique for the production of polyaniline nanoparticles (emeraldine base) claimed in claim 1 wherein the mixture is not stirred/agitated by any means. 3. A technique for the production of polyaniline nanoparticles claimed in claim 1 and claim 2 wherein there is no special control is required. 4. A technique for the production of polyaniline nanoparticles claimed in claim 1,2 and 3 wherein the developed polyaniline nanoparticles are separated from mother liquor by Buckner funnel. 5. A technique for the production of polyaniline nanoparticles claimed in claim 1,2,3 and 4 wherein the technique described with reference to the accompanying drawing (Figure-3).

Full Text

The following specification particularly describes and ascertains the nature of this invention and the manner in which it is to be performed.
The present invention relates to a procedure of "a simple route to prepare emeraldine base nanoparticles"
BACKGROUND:
Polymers due to their low electrical conductivity were mainly used as insulating materials. A breakthrough came with the in 1977 when MacDiarmid, Heeger, and Shirakawa discovered that exposure of conjugated polymer polyacetylene to iodine vapor yielded an electrically conducting material. Although their polyacetylene exhibits good electrical properties, its application is limited because of its poor stability in air and complicated synthesis methods. They were later awarded Nobel Prize in 2000. Since then, research in the field of conducting polymers was intensified searching for newer cheaper and smarter conducting polymer. During the meantime many such polymers were discovered such as polyaniline (PAni), polypyrrole (PPy), polythiophene (PTh) etc. These polymers have gained significant prominence recently because of their stability in air and optical and electrical properties.
Polyaniline is unique among the family of conjugated polymers and has attracted considerable attention due to its low cost, simple synthesis, good environmental stability, simple nonredox doping/dedoping chemistry based in acid/base reactions, and favorable optical and electrical properties. It has found potential applications in electronic and optical devices such as batteries, artificial muscles, electromagnetic shielding devices, corrosion protection coatings, sensors, capacitors, hydrogen storage, fuel cells etc.
Polyaniline was originally known in 1835 as "aniline black", a term used for any product obtained by the oxidation of aniline. Conducting properties of polyaniline were rediscovered in the early 1980s and PAni was found to have wide ranging application in various fields.
Polyaniline can be synthesized by both the electrochemical and chemical oxidative polymerization in acidic, mildly acidic and even neutral media. However, the results are very different in each situation. This may be well understood from the opinion of Prof. A.G. MacDiarmid that "there are as many different types polyaniline as there are people who synthesize it". The conducting form of polyaniline is termed as emeraldine salt whereas the nonconducting form as emeraldine base.
In recent past, the research on polyaniline and its derivatives was mainly focused on making it more processible and commercially available. It has experienced a great leap with the advent of nanoscience and nanotechnology in recent years. Synthesizing nanostructures of this unique conducting polymer has attracted special attention these days. The hope is that nanostructured polyaniline will offer better performance or new properties compared with its conventional bulk counterpart. Various research groups have conducted works involving synthesis of polyaniline nanofibers and nanoparticles. Few of these reports may be summarized as follows:
F. Yan and G. Xue prepared nanoscopic polyaniline particles in a stable water-oil microemulsion using sodium dodecylbenzenesulfonate (SDBA) which acts as surfactant as well as dopant in the acidic reaction media. J. Mater. Chem. 9,3035-3039 (1999).
Kim et. al. prepared polyaniline (PAni) dispersions consisting of 10-20 nm sized nanoparticles by oxidation with ammonium peroxydisulfate (APS) in sodium dodecylsulfate (SDS) micellar solutions. Synthetic Metals 122,297-304 (2001).
Han et. al. carried chemical oxidative polymerization of aniline in micellar solution of dodecylbenzenesulphonic acid (DBSA, anionic surfactant) to obtain conductive polyaniline nanoparticles. Synthetic Metals 126, 53-60 (2002).
Cho et. al. obtained nano-sized polyaniline (PAni) particles dispersed in aqueous solution using both poly(vinyl alcohol) (PVA) and poly(styrene sulfonic acid) (PSSA) as polymeric stabilizers. Material Science & Engineering C24,15-18 (2004).
Park et. al. synthesized monodispersed polyaniline nanoparticles by oxidative dispersion polymerization using poly(sodium-4-styrenesulfonate) (PSSA) as both a polymeric stabilizer and a doping agent due to its acidity. Current Applied Physics 4,581-583 (2004).
J. Huang and R. B. Kaner discussed mechanistic approach of nanofiber formation in the chemical polymerization of aniline. Angew. Chem. Int. Ed. 43, 5817 -5821 (2004).
J. Huang and R. B. Kaner obtained uniform polyaniline nanofibers readily formed using interfacial polymerization without using templates or functional dopants. J. Am. Chem. Soc. 126,851-855 (2004).
S. Dorey et.al. reported the synthesis of polyaniline (PAni) suspension of particles with size of about 2-3 nm. This nano-colloid was obtained by the oxidative polymerization aniline in dilute and semi-dilute solutions of sodium poly(styrenesulfonate). Polymer 46, 1309-1315, (2005).
Cholli et. al. used biocatalytic approach to prepare polyaniline nanoparticles, however, they obtained it as a composite followed by separation of PAni nanoparticles from these composites. IUPAC Pure & Applied Chemistry 97,339-344 (2005).
Li et. al. synthesized polyaniline submicrometer-sized tubes with controllable morphology by chemical oxidative polymerization of aniline with the aid of sodium dodecylbenzenesulfonate. J. Nano Res. 8,1039-1044 (2006).
Jing et. al. used the conventional oxidation route to prepare polyaniline nanoparticles but used ultrasonic irradiation instead of mechanical mixing to obtain more uniform nanostructures. Ultrasonics Sonochemistry 14,75-50 (2007).
Chen et. al. prepared a series of polyaniline (PAni) nanostructures from fiber to star-like, net-like and coral ball like by controlling the synthesis conditions such as monomer/stabilizer ratio, pH and reagent adding method and rate by diffusion polymerization. C. R. Chimie 11,84-89 (2008).
Ganeshan et. al. prepared polyaniline nanoparticles with size ranging from 20 nm to 40 nm by the pulsed sonoelectrochemical method. Synthetic Metals 158, 848-853 (2008).
Tran et. al. presented a bulk and template-free method to synthesize nanofibers of substituted polyanilines. Macromolecules 41,7405-7410 (2008).
Xingwei Li et. al. obtained stabilizer-free polyaniline nanofiber aqueous colloids by the direct dispersion of polyaniline nanofibers prepared in presence of P-cyclodextrin. Materials Letters 62,1431-1434 (2008).
Xing et. al. prepared polyaniline (PAni) nanofibers via interfacial polymerization method. In this method, aniline dissolved in xylene that is immiscible in water, was directly added into the aqueous solution of the oxidant under stirring. The polymerization was carried out at the interface formed between the organic liquid drops and the aqueous solution. Synthetic Metals 158,59-63 (2008).
I. Sapurina and J. Stejskal discussed the mechanism of the oxidative polymerization of aniline and the formation of supramolecular polyaniline structures. Polym. Int. 57,1295-1325 (2008).
Han et. al. prepared organic solvent dispersible dodecylbenzenesulfonic acid doped polyaniline (PAni) from DBSA micelles and with ammonium persulfate (APS) as an oxidant in hexane by one-step polymerization. Synthetic Metals 159,123-131 (2009).
Rahy et. al. reported that nano-emulsions can be creatively used as a morphology selective synthesis method to prepare not only nano-grains but also nano-fibers with high selectivity. Polym. Adv. Technol (2009) DOI: 10.1002/pat.l562.
Liu et. al. carried out the chemical oxidative polymerization of aniline on solid substrates treated with Au nanoparticles (Au-NPs) deposition and 4-aminothiophenol (ATP) modification. Polyaniline (PAni) fibers were obtained in micro-/nano-size with two-dimensional network structures. Synthetic Metals 159,1077-1081 (2009).
Zhang et. al. presented a new approach for the synthesis of polyaniline nanofibers under pseudo-high dilute conditions in aqueous system. Synthetic Metals 159,1508-1511 (2009).
Zhang et. al. prepared highly crystalline polyaniline (PAni) nanofibers with 16-23 nm in diameter by using FeCl3•6H2O as the oxidant in the presence of inorganic acids without any external template. Materials Chemistry and Physics 115,275-279 (2009).
Fei et. al. basically used template guided method to prepare cubic and spherical nanostructures of polyaniline. ACS Nano 3,3714-3718 (2009).
Li et. al. discussed various aspects of preparation and applications of polyaniline nanostructures. Ace. of Chem. Res. 42,135-145 (2009).
Li et. al. synthesized high quality polyaniline nanofibers by a rapid polymerization of aniline using ammonium peroxydisulfate (APS)/Fe2+ redox initiator as the oxidant without any hard or soft templates. Polymer 51,1934-1939 (2010).
Majority of work reported till date is not as simple as we are presenting here. The complex chemistry of polyaniline formation once again proved that there are lots more to do. To the first concern, we are here with a very simple route to prepare emeraldine base nanoparticles. The procedure is simple and discussed below:
1. Prepare the solutions of aniline and oxidant in aqueous solution of an inorganic acid.
2. Cool these solutions at a predetermined temperature.
3. Pour the oxidant solution into the aniline solution and keep it undisturbed for overnight at the predetermined temperature.
4. Separate polyaniline by filtration with a Buckner funnel.
5. Convert green emeraldine salt into emeraldine base nanopowder by dedoping by a predetermined dedoping agent.
The nanopowder was analyzed for FT1R (Figure-1) and TEM (Figure-2). Moreover, a flow diagram of complete procedure is given in Figure-3.

We Claim,
1. A technique for the production of polyaniline nanoparticles comprising following
steps:
a). Acidic aqueous solution of aniline of predetermined concentration is made.
b). Acidic aqueous solution of potassium persulphate of predetermined concentration is also made.
c). The two solutions were allowed to cool at a predetermined temperature.
d). Predetermined volume of potassium persulphate solutions is gently poured into the equal volume of the aniline solution in glass beaker and kept at the predetermined temperature for overnight (normally more than 14-15 hours). The polymer so obtained was filtered, washed with distilled water, dedoped with excess of predetermined dedoping agent followed by washing with distilled water and dried in air oven.
2. A technique for the production of polyaniline nanoparticles (emeraldine base) claimed in claim 1 wherein the mixture is not stirred/agitated by any means.
3. A technique for the production of polyaniline nanoparticles claimed in claim 1 and claim 2 wherein there is no special control is required.
4. A technique for the production of polyaniline nanoparticles claimed in claim 1,2 and 3 wherein the developed polyaniline nanoparticles are separated from mother liquor by Buckner funnel.
5. A technique for the production of polyaniline nanoparticles claimed in claim 1,2,3 and 4 wherein the technique described with reference to the accompanying drawing (Figure-3).

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Patent Number

279682

Indian Patent Application Number

2398/DEL/2010

PG Journal Number

05/2017

Publication Date

03-Feb-2017

Grant Date

28-Jan-2017

Date of Filing

06-Oct-2010

Name of Patentee

FAIZ MOHAMMAD

Applicant Address

PROFESSOR IN THE DEPARTMENT OF APPLIED CHEMISTRY, ALIGARH MUSLIM UNIVERSITY, ALIGARH-202002, INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	FAIZ MOHAMMAD	PROFESSOR IN THE DEPARTMENT OF APPLIED CHEMISTRY, ALIGARH MUSLIM UNIVERSITY, ALIGARH-202002, INDIA.
2	SHAHID PERVEZ ANSARI	RESEARCH SCHOLAR IN THE DEPARTMENT OF APPLIED CHEMISTRY, ALIGARH MUSLIM UNIVERSITY, ALIGARH-202002, INDIA.

PCT International Classification Number

B82

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA