Title of Invention

"A NOVEL IRON-POLY[3-OCTYLTHIOPHENE] (FE-P3OT) NANOCOMPOSITE MATERIAL AND A PROCESS FOR THE PREPARATION THEREOF"

Abstract The present invention comprises a method for a low cost synthesis of a conjugated polymer; poly(3-octylthiophene) (P30T), the creation of nano-crystallites (-100 nm) of magnetic particles (iron(Fe)) embedded in a P30T polymer matrix and subsequently patterning of supramolecular structure of Fe-P30T nanocomposite film by the application of magnetic field, characterized by various characterization techniques, which results in the improvement of the conductivity of the composite by two-three orders of magnitude. The invention provides preparation of regioregular poly(3-octylthiophene) (PEOT) at sub zero temperature (< - 40° C), in-situ preparation of metallic iron in P30T matrix and amethod to modulate structuring of Fe-P30T matrix by application of magnetic field..
Full Text FIELD OF INVENTION
The present invention relates to a novel iron-poly(3-octylthiophene) (Fe-P30T) nanocomposite material. More particularly the present invention relates to magnetic field assisted growth of iron-poly(3-octylthiophene)(Fe-P30T) nano-composite film. Still more particularly, the present invention relates to a low cost synthesis of poly(3-octylthiophene) (P30T) and creation of iron(Fe) nanomagnets in poly(3-octylthiophene) matrix, and magnetic field assisted growth of Fe-P30T nanoiron composite film at room temperature within very short period ( BACKGROUND OF THE INVENTION
The nature of a conjugated polymer i.e. intra- and inter-molecular structure and the associated structural phase behavior are fundamental issues that strongly affects the physical properties manifested by this unique class of materials. Even relatively small changes in the specific chemical architecture and/ or processing procedure can lead to significant variations in the resultant structural forms and in their physical properties. Ultimately a deeper understanding of the various structure-property interrelationship will, in part, form the foundation for future efforts that require even more specialized conjugated polymer structures with highly specific properties. The hierarchical organization of conjugated polymer structures is an exceedingly important and complex issue. Even within molecular length scales (2-200 A), there is an immense diversity with respect to the structural forms and phase behavior as described by B. Grevin,et al., in Journal of Chemical Physics, 118, 7097 (2003).
In conjugated polymers extensive main chain 7t-conjugation and its implicit stiffness with respect to the main chain bending and twisting mostly influences the over all physical behavior. As a direct consequence, virtually all linearly unsubstituted conjugated polymers are found to be intractable and infusible. These model systems also tend to form crystalline phase structures with many common features. Hence these compounds may be conveniently lumped together to form one basic class of conjugated polymer materials that have similar structural characteristics. In the quest for improved performance, better processibility, and novel applications, a wealth of newer compounds
with specific chemical architectures have been synthesized as described in the book "Science and Applications of Conducting Polymers" edited by W.R. Salaneck, D.T. Clark and E.J. Samuelsen., Adam Hilger, Bristol, 1991. The three most common approaches that have been implemented are (a) greater main chain flexibility ( e.g., polyaniline), (b) side-chain substitution (e.g. poly(3-alkylthiophene)) and (c) fabrication from a soluble precursor polymer (e.g. poly(p-xylene-a- dimethylsulfonium chloride) to yield poly(p-phenylenevinylene). These all have been described by E. M. Genies, et al., in Synthetic Metals, 36, 139 (1990); T. Yamamoto, et al., in Chem. Ind.l, 301 (1982) and D.R. Gagnon, et al., in Synthetic Metals, 20, 85 (1987). All these modifications can produce materials with a range of structural forms and, in some instances, striking new physical behavior. Side chain substitutions are now routinely used to enhance solvent solubility and fusibility so that various conventional polymer-processing methods may be used. Important here is to note that some of these polymeric materials, e.g. poly(3-alkylthiophene) family of polymers, may contain only a small volume fractions of
electrically active regions (i.e., the 71 conjugated main chain). Still these materials can exhibit extremely high dc conductivity after doping (or more precisely, intercalation) by a guest species as described by J.P. Pouget, et al., in Macromolecules, 24, 779 (1991). This intercalation process can also provoke significant dimensional changes in the molecular unit construction. This latter property enables the fabrication of novel self structuring devices as described by R.D. McCullough, et al., in J. Chemical Society Chemical Communication, 1, 70 (1992). Even more exotic synthesis and processing procedures have further expanded the horizons within the structure-property interrelationships and the potential for new applications. Langmuir-Blodgett mono-layer film deposition technique has been applied successfully to yield thin film multi-layer heterostructures for use as electronic devices as described by I. Watanabe, et al., in Journal of Chemical Physics, 92, 444, (1990). Chemical coupling of various ion selective crown ethers can
create conjugated polymer hosts in which the extent of main-chain 71 conjugation is directly influenced by the solution concentration of a specific ion when immersed. In all these examples it is often the subtle interplay between the molecular level structural ordering and the electroactive nature of the conjugated polymer host that gives rise to
those properties as described by T.M Swager, et al., in J. Macromol. Sci., A31, 1893 (1994).
Poly(3-alkylthiophenes) having regioregularity more than 98 % have been synthesized using multi step regiocontrolled process mediated by Rieke zinc as described by T-A Chen, et al., in Journal of American. Chemical. Society. 117, 233(1995). Poly(3-alkylthiophenes) have been tested as semi-conducting components of polymer field-effect transistor (FETs) because their ordered supramolecular organization results in improved electrical transport properties. For example, in field-effect transistor (FETs) made of regioregular poly(3-hexylthiophene), field-effect mobility as high as 0.1 cm-1V 'S"1 has been achieved as described by B. Grevin, et al., in Journal of Chemical Physics, 118, 7097 (2003). Still high cost of synthesis of poly(3-alkylthiophenes) involving costly reagents and multi step process need to be addressed.
Magnetic nanoparticles embedded in a polymer matrix have excellent potential for electromagnetic device applications. Several advanced polymer composites have been synthesized with a wide variety of inclusions like metals, semiconductors, carbon nanotubes, and magnetic nanoparticles as described by S. Jain et al., in International Journal of Nanoscience, 3, 631 (2004), Keller, et al., US Patent, 6,673,953, Jan. 6, 2004. Many attractive properties of polymers like noncorrosiveness, light weight, mechanical strength, and dielectric tunability can be utilized along with magnetic and optical properties of nanoparticles to make multifunctional materials. Inclusion of ferromagnetic or superparamagnetic nanoparticles in polymers is especially important as magnetic nanoparticles have shown promise in various potential applications like spin polarized devices, carriers for drug delivery, magnetic recording media, high-frequency applications, etc. However, for most of these highly specialized applications, there is a practical need to disperse the nanoparticles in nonmagnetic media that can be easily processed as described by D. N. Mcllroy et al., in Journal of Applied Physics 87, 7213 (2000). Polymeric materials are very well suited for this purpose as described by J. L. Wilson et al., in Journal of Applied Physics, 95, 1439 (2004), and by I. Manners, in Science 294, 1664 (2001) and other related works. However, its applications strongly depend on the formation of especially tailored nanostructured surfaces in addition to
inclusion of magnetic particles as described by C, Zhang et al., in Applied Physics Letters, 95,1439 (2004), B. D. Terris et al., Journal of Applied Physics, 87, 7004(2000), A, Theron, et al., Nanotechnology, 12, 384 (2001), Kuo et al., in US Patent, 6,396,773, May 28, 2002, Witcraft, et al., in US Patent, 5,820,924, Oct. 13, 1998, Ao. et al., in US Patent, 5,618,738, April 8,1997 and other related works.
The need for high capacity and inexpensive data storage is required for increasingly sophisticated handheld applications such as high resolution cameras, palm top computers, mobiles phones, etc. This is driving research on material systems and architectures for memory devices. High capacity and low cost write-once-read-many-times (WORM) memories have advantages over rewritable memories for archival storage applications such as flash memory cards and miniature hard disks. For example, WORM memories require no energy to refresh data; an especially important feature for mobile and handheld applications. Furthermore, they are fast and easy to access, and do not require fragile and energy consumptive mechanical disk drives. These all have been described by S. Molier, et al. in Journal of Applied Physics, 94,7811 (2003).
OBJECTIVES OF THE INVENTION
The main object of the present invention is to provide a method for a low cost synthesis of a conjugated polymer; poly(3-octylthiophene)(P30T).
Yet another object is to create magnetic nanoparticles in poly(3-octylthiophene) forming Fe-P30T nanocomposite.
Still another object is to create specific pattern of magnetic nanoparticles in Fe-P30T nanocomposite film at room temperature within an hour.
SUMMARY OF THE INVENTION
The basic idea of this invention is that in the doped state (by magnetic particles) the conjugated polymers film can be grown under the influence of applied magnetic field then the doped magnetic particles in the conjugated polymer matrix should be aligned along in the direction of magnetic lines of forces of externally applied magnetic field in order to provide an ordered supramolecular structure useful for semiconductor device
applications. One immediate effect of ordered supramolecular structure has been identified as enhancement in composite conductivity by two-three orders of magnitude as a result of formation of aligned nano crystallites under the influence of magnetic field. By controlling the temperature for exothermic reactions- as polymerization of poly(3-octylthiophene) is an exothermic reaction- one can get optimum quality and quantity of product especially in the case of growth of polymers whereas increase in temperature(for exothermic reaction) leads to faster chain termination and hence formation of short chains polymer. For polymerization of poly(3-octylthiophene) the optimum temperature has been found to be -35°C.
The novelty of the present invention lies in modulation of supramolecular structure of Fe-P30T nanocomposite film by the application of magnetic field, characterized by various characterization techniques which results in the improvement in conductivity by two-three orders of magnitude.
(figure removed)
DETAIL DESCRIPTION OF THE INVENTION
Accordingly the present invention provides an iron-poly(3-octylthiophene) (Fe-P30T) nanocomposite material having the following characteristics: i) a molecular weight (Mw) in the range of 30000 to 35000 ii) a number average molecular weight (Mn) in the range of 27000 to 32000, iii) a poly-dispersity (Mw/Mn) in the range of 1.16 to 1.06 iv) conductivity in the range of 7.8x10"9 to 8.1 1xl0-6 S/cm.
The present invention further provides a process for the preparation of Fe intercalated poly(3-octylthiophene) nanocomposite material having the following characteristics:
i) a molecular weight (Mw) in the range of 30000 to 35000
ii) a number average molecular weight (Mn) in the range of 27000 to 32000,
iii) a poly-dispersity (Mw/Mn) in the range of 1.16 to 1.06 iv) conductivity in the range of 7.8xl0"9 to 8.1 1x10-6 S/cm,
the said process comprising the steps of:
(a) adding 3-octylthiophene monomer in a suspension of FeCl3 in a polar solvent, with a molar ratio of monomer to FeCi3 in the range of 0.17 to 0.25, at a temperature in the range of -5°C to -40°C for a period of 10-12 hrs under stirring in an inert atmosphere (N2), increasing the temperature of the above said reaction mixture to a temperature in the range of 25-30°C, over a period of 1-2 hrs, under constant stirring at 200-1000 rpm, followed by further stirring for another 10-12 hrs, there after precipitating the FeCl3 intercalated poly(3-octylthiophene) by adding an organic solvent,
(b) suspending the above said FeCl3 intercalated poly(3-octylthiophene) in an organic solvent (chloroform), adding liquid ammonia to the above said suspension, at a temperature in the range of 20-30°C, dissolving the above said suspension to make a clear chlorine free Fe-P3OT nanocomposite solution by slowly increasing the temperature of the above said reaction mixture to a temperature of 40-50°C, evaporating the solvent for the above
said resultant solution to obtain the desired Fe-P30T nanocomposite material,
dissolving the above said Fe-P30T in an organic solvent, treating the above said polymer solution with an aqueous solution of ethylenediaminetetraacetic acid( EDTA), evaporating the organic solvent from the above said reaction mixture at a temperature of 50-60°C to obtain the pristine P30T film,
dissolving the Fe-P30T composite material obtained in step b) in an organic solvent, and casting it over a solid support, keeping the above said casted solution in the presence of a magnetic field having a strength in the range of 0.1-1.0 T till the complete evaporation of the solvent to obtain the desired magnetic field assisted Fe- P30T nanocomposite material film.
In an embodiment of the present invention the polar organic solvent used for making FeCl3 suspension is selected from group consisting of chloroform, benzene, toluene, chlorobenzene and tetrahydrofuran.
In yet another embodiment the organic solvent used for precipitating the FeCl3 intercalated P30T is selected from methanol and ethanol.
In yet another embodiment the organic solvent used for making a suspension of P30T-FeCl3 is selected from the group consisting of chloroform, benzene, toluene, chlorobenzene and tetrahydrofuran.
In yet another embodiment the organic solvent used for making a casting solution for growing a Fe-P30T film the group consists of chloroform, benzene, toluene, chlorobenzene and tetrahydrofuran.
In yet another embodiment the magnetic field used for growing Fe-P30T nanocomposite film is in the range of 0.1-1.0 T.
In yet another embodiment the conductivity of the Fe-P30T nanocomposite material obtained is in the range of 7.8x10-9 to 8.11x10-6 S/cm.
In yet another embodiment the nanocomposite material obtained has an intercalated magnetic metal selected from the transition metal chloride group consisting of iron(IH), molybdenum(V) and ruthenium(III).
The following examples are given by the way of illustration and therefore should not be construed to limit the scope of the invention.
EXAMPLE 1
A suspension of 6.488g (0.4 moles) of anhydrous ferric chloride (FeCl3) was made in 100 ml of chloroform to use as an oxidizing solution for polymerization of 3-octylthiophene monomer at -5°C by chemical polymerization technique to get poly(3-octylthiophene) . To this oxidizing solution kept at -5°C, 2.135 ml (0.1 mol) of 3-octylthiophene monomer was added drop wise for 2 hrs. The solution is stirred throughout with a stirrer. The atmosphere of polymerizing solution is made inert by continuous passing of dry N2 gas, and stirring continued for another 10 hrs, at the same temperature. The temperature of the polymer solution was intentionally increased up to 25°C in 1 hr. and was further stirred for another 12 hrs under N2 gas atmosphere. To precipitate polymer, sufficient amount of methanol is added. A greenish-black polymer obtained was thoroughly washed subsequently with methanol, water, propanol and again by methanol till the unreacted monomer, excess oxidant, and oligomers were completely removed. Polymer powder so obtained is dried at 80° C under reduced pressure in a dynamic vacuum. Amount of polymer along with intercalated FeCl3 was weighed to 1.6465g. Intercalated FeCl3 in polymer matrix was subsequently used as source of iron. The Fe-P30T nanocomposite material obtained was characterized by Fourier transform infrared(FTIR), Ultravoilet-Visible(UV-Vis), X-ray differaction(XRD), Scanning electron microscope(SEM), Atomic force microscope(AFM) and Scanning tunneling microscope(STM) and the product was found to be nanocomposite material composed of iron(Fe) nanoparticles and poly(3octylthiophene)(P30T).
EXAMPLE 2
Procedure followed was same as in EXAMPLE 1 keeping temperature (-5°C) of polymerization same, and altering the concentration of oxidant in order to vary oxidant to monomer ratio. A suspension of 12.977g (0.8 moles) of anhydrous ferric chloride (FeCl3) was made in 100 ml of chloroform to use as an oxidizing solution for polymerization of 3-octylthiophene monomer at -5° C. To this oxidizing solution kept at -5° C, 2.135 ml (0.1
mol) of 3-octylthiophene monomer was added drop wise as in EXAMPLE 1. Polymer powder so obtained is dried at 80° C under reduced pressure in a dynamic vacuum. Amount of polymer along with intercalated FeCl3 was weighed to 1.887g and greenish black in color.
EXAMPLE 3
Procedure followed was same as in EXAMPLE 1 keeping oxidant to monomer ratio(0.8/0.1) same as in EXAMPLE 2 lowering the temperature from -5°C to -20°C, in order to investigate the effect of polymerization temperature on the quality of polymer formed. A suspension of 12.977g (0.8 moles) of anhydrous ferric chloride (FeCh) was made in 100 ml of chloroform to use as an oxidizing solution for polymerization of 3-octylthiophene monomer at -20° C. To this oxidizing solution kept at -20° C, 2.135 ml (0.1 mol) of 3-octylthiophene monomer was added drop wise as in EXAMPLE 1. Polymer powder so obtained is dried at 80° C under reduced pressure in a dynamic vacuum. Amount of polymer along with intercalated FeCU was weighed to 2.115g and composite was greenish black in color.
EXAMPLE 4
Procedure followed was same as in EXAMPLE 1 keeping oxidant to monomer ratio (0.8/0.1) same as in EXAMPLE 2 lowering temperature further to -35°C. A suspension of 12.977g (0.8 moles) of anhydrous ferric chloride (FeCl3) was made in 100 ml of chloroform to use as an oxidizing solution for polymerization of 3-octylthiophene monomer at -35° C. To this oxidizing solution kept at -35° C, 2.135 ml (0.1 mol) of 3-octylthiophene monomer was added drop wise as in EXAMPLE 1. Polymer powder so obtained is dried at 80° C under reduced pressure in a dynamic vacuum. Amount of polymer along with intercalated FeCU was weighed to 2.354g and composite was greenish black in color. 16 EXAMPLE 5
Procedure followed was same as in EXAMPLE 1 keeping oxidant to monomer ratio(0.8/0.1) same as in EXAMPLE 2 lowering temperature still further to -40°C. A suspension of 12.977g (0.8 moles) of anhydrous ferric chloride (FeCl3) was made in 100
ml of chloroform to use as an oxidizing solution for polymerization of 3-octylthiophene monomer at -40° C. To this oxidizing solution kept at -40° C, 2.135 ml (0.1 mol) of 3-octylthiophene monomer was added drop wise as in EXAMPLE 1. Polymer powder so obtained is dried at 80° C under reduced pressure in a dynamic vacuum. Amount of polymer along with intercalated FeCl1 was weighed to 1.55 lg and composite was greenish black in color.
All these results obtained in EXAMPLE 1-5 are summarized in TABLE 1 alongwith their characteristic aromatic C-H out-of-plain vibrations at and around 822 cm-1 which is the characteristics of 2,5-disubstituted-3-octylthiophene. Optimum condition for polymerization was found at -35°C of EXAMPLE 4. Methods for the preparation of other conjugated polymer films have been described by Kaneko et al, in US Patent No. 5,306,443, Apr. 26,1994. Detailed polymerization parameters, IR-absorptions and UV-Vis. characteristics of the present work alongwith its comparison with reported work of T-A. Chen, et al., in Journal of American Chemical Society 117, 233,1995. are summarized in TABLES 1,2 and 3.
METHOD FOR THE CREATION OF IRON NANO MAGNETS IN POLY(3-OCTYLTHIOPHENE) MATRIX
EXAMPLE 6
1.6465g P30T-FeCl3 matrix as obtained in EXAMPLE 1-5, was suspended in chloroform (100 ml), 100 ml of liquid ammonia was added to the above said suspension and was heated at 40° C. Polymer starts to dissolve in chloroform phase resulting into red-brown paste. Repeating this step 5 times resulted into removal of chloride part leaving iron and latter forming clusters of nanoiron (~100 nm) in P30T matrix. Elemental detection technique shows 6.39% elemental or 1.66% atomic iron (Fe) in P30T matrix. Fe-P30T-nanocomposite is soluble in polar organic solvents e.g. chloroform, benzene, chlorobenzene, tetrahydrofuran, toluene. Formation of nanosized iron was revealed by X-ray diffraction analysis which was subsequently confirmed by comparison with the work reported by J. L. Wilson, et al. in Journal of Applied Physics
95, 1439(2004). Molecular weight (Mw) = 62152, number average molecular weight (Mn)= 17369 and poly-dispersity (Mw/Mn) = 3.578.
EXAMPLE 7
Dissolving the above said Fe-P30T in an organic solvent, treating the above said polymer solution with an aqueous solution of ethylenediaminetetraaceticacid (EDTA), evaporating the organic solvent from the above said reaction mixture at a temperature of 50-60°C, repeatedly to obtain the pristine P30T. The conductivity obtained for the pristine P30T is found to be~2xl0"8S/cm.
PATTERNING Fe-P30T-NANOCOMPOSITE FILM BY APPLICATION OF EXTERNAL MAGNETIC FIELD
EXAMPLE 8
0.05g Fe-P30T-nanocomposite powder was taken in 15 ml chloroform. The Fe-P30T-nanocomposite-chloroform solution was taken on flat glass substrate (7.5x2.5 cm ) under applied magnetic field (0.1-1 T) at room temperature (25°C). The evaporation (~1 hr.) of the solvent results into solid polymer film in which nanoiron arrays as well as polymer chains are found to have properly aligned as shown in FIG. 7 & 8.
EXAMPLE 9
The effect of dilution or time of solvent evaporation/film formation has been taken into consideration by taking highly concentrated composite solution (0.05g in 5 ml) keeping other parameters same as in EXAMPLE 8. Free standing Fe-P30T-nanocomposite film having good mechanical strength obtained within 10 minutes. The film obtained is masked by metal plate having 5 mm (dia) for gold coating on both sides of the films. The dc conductivity of these films was measured by two probe method using Kethley 617 programmable electrometer. The conductivity of the films grown without and with magnetic field for different solution concentration alongwith different solvent used for the present work are summarized in TABLE 4.
(TABLE REMOVED)


Tian-An Chen, Xiaoming Wu, and Reuben D. Rieke, J. Am. Chem. Soc. 117, 233, 1995.
lower wave number (cm"1) for aromatic C-H out of plain vibration is indicative of synthesis of regioregular (rr-) P30T polymer of improved quality in the present invention which has superior properties as compared to its regiorandom (rdm-) counterpart.
(TABLE REMOVED)


• Choice of solvent has hardly any effect on conductivity of composite film grown
under different magnetic field strength. Solvent tried; chloroform, benzene,
toluene, chlorobenzene.
• Attempt to increase Fe concentration results into increase in insolubility of
composites powder in common solvents. Other options are being tried results are
expected in due course.
• P30T+Fe powder treated repeatedly by EDTA (0.05 M) till no Fe content, do not
show any change in conductivity with change of magnetic field.
FIGURE CAPTIONS FOR DRAWINGS AND PHOTOGRAPHS
FIG. 1 FT-IR spectrum of poly(3-octylthiophene)(P30T) film. The spectrum was
recorded on Model 2000 Perkin Elmer FT-IR spectrometer.
FIG. 2 UV-Vis spectrum of poly(3-octylthiophene)(P30T) (a) solution in chloroform
and (b) film on simple glass slide.
FIG. 3 Electromagnetic setup for generating magnetic field (parallel mode) up to IT
under which composite films have been grown.
FIG. 4 X-ray diffraction pattern of Fe-P30T-nanocomposite film grown without
magnetic field. The spectrum was recorded on PW 1710 based diffractometer. Inset of
FIG.4. is scanning electron micrograph of Fe-P30T-nanocomposite film grown without
magnetic field showing nondirectional clusters of nanoiron in P30T matrix
FIG. 5 X-ray diffraction pattern of Fe-P30T-nanocomposite film grown under applied
magnetic field (~1 T). The spectrum was recorded on PW 1710 based diffractometer.
Inset of FIG. 5 is scanning electron micrograph of Fe-P30T-nanocomposite film grown
under magnetic field confirming the alignment of nanoiron arrays (shown by arrows).
FIG. 6 AFM picture of Fe-P30T-nanocomposite film grown without magnetic field. The
picture was taken by Nano Scope II Digital Instruments, Inc. USA.
FIG. 7 AFM picture of Fe-P30T-nanocomposite film grown under applied magnetic field
(-1 T). The picture was taken by Nano Scope II Digital Instruments, Inc. USA.
FIG. 8 STM picture of Fe-P30T-nanocomposite film grown under applied magnetic field
(~1 T) showing intercalation of nanoiron arrays alongwith P30T chains. The picture was
taken by Nano Scope II Digital Instruments, Inc. USA.
BRIEF DESCRIPTION OF DRAWINGS AND PHOTOGRAPHS
FIG. 1 depicts the FT-IR spectrum of poly(3-octylthiophene) film. The ring stretching vibrations are at 1510 cm'1, 1465 cm"1 and the aromatic C-H stretching vibrations is at 3056 cm'1. The aromatic C-H out-of-plain vibration at 822 cm"1 is the characteristics of 2,5-disubstituted-3-octylthiophene. The characteristics vibration of 2,5-disubstituted-3-octylthiophene at 822 cm"1 which is used to assign whether the resultant polymer is regioregular or regiorandom and hence the quality of polymer. This has been described
by T-A. Chen, et al., in Journal of American Chemical Society, 117, 233, 1995. The details of the band positions as obtained in FIG. 1 for poly(3-octylthiophene) film and their assignments along with their comparison with reported work for regeoregular (rr-) and regiorandom (rdm-) have been given in TABLE 2.
FIG.2 depicts the UV-Vis. spectrum of poly (3-octylthiophene) film on simple glass slide and dilute solution of P30T in chloroform. The P30T has a maximum absorption wavelength at ~ 510 nm (n-n* transition energy) and two soldier peaks at -550 and -590 nm for P30T film. The band gap is -1.9 eV. The P30T in chloroform solution has a maximum absorption wavelength at -480 nm (n-n* transition energy) and it comparison with the reported work of T-A. Chen, et al., in Journal of American Chemical Society, 117,233,1995 in terms of rr- and rdm-P30T have been given in TABLE 3.
FIG. 3 depicts the electromagnetic setup for generating magnetic field under which composite films have been grown. Distance between the two poles (N & S) is 4 cm and current applied is 5-50 Amp to generate a magnetic field - 0.1-1 T. Magnetic field has been applied along the composite solution (parallel magnetization), (a) film formation under parallel magnetic field: composite solution in chloroform was taken on a flat glass slide inbuilt in a PTFE container. With progress of time chloroform evaporates at room temperature resulting into patterned solid Fe-P30T nanocomposite film, (b) A visual of patterned nanoiron arrays in polymer (P30T) matrix along the direction of applied magnetic field.
FIG. 4 depicts the X-ray diffraction spectrum of Fe-P30T nanocomposite film grown without magnetic field. It shows formation of clustered nano-crystallites in largely amorphous polymer matrix. Inset of FIG. 4 is scanning electron micrograph of Fe-P30T nanocomposite film grown without magnetic field showing nondirectional clusters of nanoiron in P30T matrix.
FIG.5 depicts the X-ray diffraction spectrum of Fe-P30T nanocomposite film grown under magnetic field (~1 T) showing an increase in peak intensity as compared with that of FIG. 4 supporting the formation of oriented clustered nano-crystallites in as shown in the inset of FIG. 5. Inset of FIG. 5 is scanning electron micrograph of Fe-P30T nanocomposite film grown under magnetic field (~1 T) confirming alignment of nanoiron arrays (shown by arrows).
FIG. 6 & FIG. 7 show the atomic force microscopy (AFM) pictures of Fe-P30T nanocomposite films grown without and with magnetic field, respectively. These pictures clearly show the alignment of nanoiron arrays (FIG. 7) due to application of magnetic field during the film formation.
FIG. 8 depicts the scanning tunneling microscopy (STM) picture showing periodic intercalation of nanoiron arrays (curved solid line) in between P30T chains (squares represent thiophene moiety attached with -octyl side chains) at molecular level for Fe-P30T nanocomposite film grown under magnetic field.
ADVANTAGES
The present invention provides a Fe-P30T nanocomposite film.
The Fe-P30T nanocomposite film obtained has an enhanced conductivity when grown under magnetic field.
This invention provides a single step, low cost process for the preparation of P30T polymer.




An iron-poly(3-octylthiophene) (Fe-P30T) nanocomposite material having the following characteristics:
i) a molecular weight (Mw) in the range of 55000 to 65000, ii) a number average molecular weight (Mn) in the range of 15000 to 18000, iii) a poly-dispersity (Mw/Mn) in the range of 3.66 to 3.61, iv) conductivity in the range of 7.8xl0"9 to 8.1 lxlO"6 S/cm. A process for the preparation of Fe intercalated poly(3-octylthiophene) nanocomposite material having the following characteristics: i) a molecular weight (Mw) in the range of 55000 to 65000, ii) a number average molecular weight (Mn) in the range of 15000 to 18000, iii) a poly-dispersity (Mw/Mn) in the range of 3.66 to 3.61, iv) conductivity in the range of 7.8xl0'9 to 8.1 lxlO"6 S/cm, the said process comprising the steps of:
a) adding 3-octylthiophene monomer in a suspension of FeCU in a polar solvent, with a molar ratio of monomer to FeCb in the range of 0.17 to 0.25, at a temperature in the range of -5°C to -40°C for a period of 10-12 hrs under stirring in an inert atmosphere (N2), increasing the temperature of the above said reaction mixture to a temperature in the range of 25-30°C, over a period of 1-2 hrs, under constant stirring of 200-1000 rpm, followed by further stirring for another 10-12 hrs, there after precipitating the FeCl3 intercalated poly(3-octylthiophene) (P30T) by an organic solvent,
b) suspending the above said FeCU intercalated poly(3-octylthiophene) in an organic solvent (chloroform), adding liquid ammonia to the above said suspension, at a temperature in the range of 20-30°C, dissolving the above said suspension to make a clear chlorine free Fe-P30T nanocomposite solution by slowly increasing the temperature of the above said reaction mixture to a temperature of 40-5 0°C, evaporating the solvent from the above said resultant solution to obtain the desired Fe-P30T nanocomposite material,
c) dissolving the above said Fe-P30T nanocomposite material in an organic solvent, treating the above said polymer solution with an aqueous solution of ethylenediaminetetraacetic acid ( EDTA), evaporating the organic solvent from the above said reaction mixture at a temperature of 50-60°C to obtain the pristine P30T film,
d) dissolving the Fe-P30T nanocomposite material obtained in step (b) in an organic solvent, and casting it over a solid support, keeping the above said casted solution in the presence of a magnetic field having a strength in the range of 0.1-1.0 T till the complete evaporation of the solvent to obtain the desired magnetic field assisted Fe-P30T nanocomposite material film.






We claim
(1) An iron-poly(3-octylthiophene) (Fe-P30T) nanocomposite material having the
following characteristics:
i) a molecular weight (Mw) in the range of 30000 to35000
ii) a number average molecular weight (Mn) in the range of 27000 to 32000
iii) a poly-dispersity (Mw/Mn) in the range of 1.16 to 1.06,
iv) conductivity in the range of 7.8x10-9 to 8.1 1x10-6 S/cm.
(2) A process for the preparation of Fe intercalated poly(3-octylthiophene) nanocomposite material having the following characteristics:
i) a molecular weight (Mw) in the range of 30000to35000,
ii) a number average molecular weight (Mn) in the range of 27000 to32000
iii) a poly-dispersity (Mw/Mn) in the range of 1.16 to 1.06,
iv) conductivity in the range of 7.8xl0-9 to 8.1 lx10-6 S/cm,
the said process comprising the steps of:
a) adding 3-octylthiophene monomer in a suspension of FeCl3 in a polar solvent, with a molar ratio of monomer to FeCl3 in the range of 0.17 to 0.25, at a temperature in the range of-5°C to -40°C for a period of 10-12 hrs under stirring in an inert atmosphere (N2), increasing the temperature of the above said reaction mixture to a temperature in the range of 25-30°C, over a period of 1-2 hrs, under constant stirring of 200-1000 rpm, followed by further stirring for another 10-12 hrs, there after precipitating the FeCl3 intercalated poly(3-octylthiophene) (P30T) by an organic solvent,
b) suspending the above said FeCl3 intercalated poly(3-octylthiophene) in an organic solvent (chloroform), adding liquid ammonia to the above said suspension, at a temperature in the range of 20-30°C, dissolving the above said suspension to make a clear chlorine free Fe-P3OT nanocomposite solution by slowly increasing the temperature of the above said reaction mixture to a temperature of 40-50°C, evaporating the solvent from the above said resultant solution to obtain the desired Fe-P3OT nanocomposite material,
c) dissolving the above said Fe-P30T nanocomposite material in an organic solvent, treating the above said polymer solution with an aqueous solution of ethylenediaminetetraacetic acid ( EDTA), evaporating the organic solvent from the above said reaction mixture at a temperature of 50-60°C to obtain the pristine P30T film,
d) dissolving the Fe-P30T nanocomposite material obtained in step (b) in an organic solvent, and casting it over a solid support, keeping the above said casted solution in the presence of a magnetic field having a strength in the range of 0.1-1.0 T till the complete evaporation of the solvent to obtain the desired magnetic field assisted Fe-P30T nanocomposite material film.
(3) A process as claimed in claim 2(a), wherein the polar organic solvent used for making FeCl3 suspension is selected from group consisting of chloroform, benzene, toluene, chlorobenzene and tetrahydrofuran.
(4) A process as claimed in claim 2(a), wherein the organic solvent used for precipitating the FeCl3 intercalated P30T is selected from methanol and ethanol.
(5) A process as claimed in claim 2(b), wherein the organic solvent used for making a suspension of P30T-FeCl3 is selected from the group consisting of chloroform, benzene, toluene, chlorobenzene and tetrahydrofuran.
(6) A process as claimed in claim 2(d), wherein the organic solvent used for making a casting solution for growing a film the group consists of chloroform, benzene, toluene, chlorobenzene and tetrahydrofuran.
(7) A process as claimed in claim 2(d), wherein the magnetic field used for growing Fe-P30T nanocomposite film is in the range of 0.1 -1.0 T.
(8) A process as claimed in claim 2, wherein the conductivity of the Fe-P3OT nanocomposite material obtained is in the range of7.8xl0-9 to 8.11xl0-6S/cm.
(9) A process as claimed in claim 2, wherein the nanocomposite material obtained has an imtercalated magnetic metal selected from the transition metal chloride group consisting of iron(III), molybdenum(V) and ruthenium(III).
(10). An iron-poly(3-octylthiophene) (Fe-P3OT) nanocomposite material and aprocess for the preparation thereof substantially as herein described with reference to the examples and drawings accompanying this specification.

Documents:

2845-DEL-2005-Abstract-(02-02-2011).pdf

2845-DEL-2005-Abstract-(07-03-2011).pdf

2845-del-2005-abstract.pdf

2845-DEL-2005-Claims-(02-02-2011).pdf

2845-DEL-2005-Claims-(07-03-2011).pdf

2845-del-2005-claims.pdf

2845-DEL-2005-Correspondence-Others-(02-02-2011).pdf

2845-DEL-2005-Correspondence-Others-(07-02-2011).pdf

2845-DEL-2005-Correspondence-Others-(07-03-2011).pdf

2845-del-2005-correspondence-others.pdf

2845-DEL-2005-Description (Complete)-(02-02-2011).pdf

2845-DEL-2005-Description (Complete)-(07-03-2011).pdf

2845-del-2005-description (complete).pdf

2845-DEL-2005-Form-1-(07-02-2011).pdf

2845-del-2005-form-1.pdf

2845-del-2005-form-18.pdf

2845-del-2005-form-2.pdf

2845-DEL-2005-Form-3-(02-02-2011).pdf

2845-DEL-2005-Petition 137-(07-02-2011).pdf

2845-DEL-2005-Petition 137-(07-03-2011).pdf


Patent Number 248779
Indian Patent Application Number 2845/DEL/2005
PG Journal Number 34/2011
Publication Date 26-Aug-2011
Grant Date 24-Aug-2011
Date of Filing 25-Oct-2005
Name of Patentee COUNCIL OF SCIENTIFIC & INDUSTRIAL RESEARCH
Applicant Address ANUSANDHAN BHAWAN, RAFI MARG, NEW DELHI-110001, INDIA.
Inventors:
# Inventor's Name Inventor's Address
1 RAMADHAR SINGH NPL, DELHI, INDIA.
2 JITENDRA KUMAR NPL, DELHI, INDIA.
PCT International Classification Number C01B 33/144
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA