KR20110101326A - Aniline fucntionalized polyfluorene nanocomposites and the preparation method thereof - Google Patents

Abstract

The present invention relates to a poly-fluorene nanocomposite containing aniline useful as a material material such as a solar cell, a fuel cell catalyst, a biosensor, and a manufacturing method thereof. More specifically, the present invention relates to poly (4,4'-9-fluorenylidene) through chemical oxidative polymerization of 4,4'-9-fluorenylidene dianiline (FDA) using an initiator. To provide a process for preparing dianiline) (PFDA) and PFDA prepared therefrom.

Description

Polyfluorene nanocomposites containing aniline and preparation methods thereof {Aniline Fucntionalized Polyfluorene Nanocomposites and the Preparation Method Thereof}

The present invention relates to a poly-fluorene nanocomposite containing aniline useful as a material material such as a solar cell, a fuel cell catalyst, a biosensor, and a manufacturing method thereof. More specifically, poly (4,4'-9-fluorenylidene dianiline) by chemical oxidative polymerization of 4,4'-9-fluorenylidene dianiline (FDA) with an initiator It is to provide a method for preparing (PFDA) and PFDA prepared therefrom.

Polymer solar cells have become competitive in place of conventional inorganic solar cells due to the possibility of versatility of materials for desirable properties, ease of manufacture, processing, and low cost. The power conversion efficiency of polymer solar cells is significantly improved from 0.01% to 5.2% under AM 1.5 G (100 mWcm ^-2 ) [Coakley KM, McGehee MD (2004) Chem. Mater. 16: 4533 3. Shaheen SE, Brabec CJ, Sariciftci NS (2001) Appl. Phys. Lett. 78: 841 4. Li G, Shrotriya V, Huang JS, YaoY, Moriarty T, Emery K, Yang Y (2005) Nature. Mater 4: 864]. It can also be improved through optimization of the device structure and development of better materials [Reyes-Reyes M; Kim K, Dewald, J, Lopez-Sandoval R, Avadhanula, A, Curran S, Carroll DL (2005) Org. Lett. 7: 5749].

At present, the synthesis of polymer solar cells with high power conversion efficiency is very desirable. In order to achieve this goal, an important configuration of optical absorption, electrical structure, and electrophoretic properties of polymer solar cells should be used.

Polyfluorene (PF) is used in solar cells because of its optoelectronic properties, good thermal and chemical stability, high fluorescence quantum yield, good film formation and hole-transporting ability [Li YN, Ding JF, Day M, Tao Y , Lu JP, D'iorio M. Chem Mater 2004; 16 (11): 2165-73]. PF is an ideal base material with proper chemical control, which makes it possible to tailor the properties to be suitable for solar cell applications. In addition, polyfluorene has a wide band gap and shows blue light emission.

However, the large band gap of polyfluorene makes copolymers less suitable for photovoltaic applications. Alternative copolymer structures with donor and acceptor functions are very effective in reducing the gap of polymers, and many have been developed to develop new donor / acceptor (DA) with fluorene and its derivatives. There was an attempt. [b) Slooff, LH; Veenstra, SC; Kroon, JM; Moet, DJD; Sweelssen, J .; Koetse, MM Appl. Phys. Lett. 2007 , 90 , 14350]. In addition, when a copolymer of polyfluorene is synthesized, various emission colors ranging from yellow, green, and red can be obtained.

Fluorene polymers substituted with the position of C-9 have better solubility and progression [Klaerner, G .; Miller, RD; Macromolecules 1998, 31, 2007]. Useful and functional substituents on the position of C-9 in fluorene can purify harmonized properties [TA Skotheim, JR Reynolds (Eds.), Handbook of Conducting Polymers- Conjugated Polymers: Processing and Applications, third ed., CRC Press Taylor and Francis Group, Bacon, 2007]. The introduction of an appropriate co-monomer unit with polyfluorene can tune the electrical and optical properties of the copolymers. Preference is given to copolymers having a low band gap and a broad range of solar spectra.

Thus, the inventors have substituted aniline at the C-9 position of fluorene to provide low band gap electronics, excellent emission characteristics that emit green light in LEDs, and absorption of visible and infrared regions in solar cell applications. Poly (4,4'-9-fluorenylidene dianiline) (PFDA) having properties and methods for preparing the same have been devised.

It is an object of the present invention to provide a polyfluorene nanocomposite comprising aniline and a method for preparing the same. More specifically, the present invention provides poly (4,4′-9-fluorenylidene dianiline) (PFDA) and a method for preparing the same by chemically oxidizing the FDA using an initiator. It is also an object of the present invention to provide a method for producing a nanostructure of poly (4,4'-9-fluorenylidene dianiline) (PFDA) according to the above production method in the presence of a surfactant.

In order to achieve the object of the present invention as described above, the present invention provides a method for preparing poly (4,4'-9-fluorenylidene dianiline) (PFDA).

Hereinafter, the present invention will be described in detail.

a) dissolving 4-4'-9-fluorenylidene dianiline (FDA) in hydrogen chloride (HCL);

b) stirring the solution;

c) adding an initiator;

It provides a method for producing poly (4,4'-9-fluorenylidene dianiline) (PFDA) by the chemical oxidative polymerization (FDA) of the FDA.

In step b), 4-4'-9-fluorenylidene dianiline (FDA) is dissolved in a hydrogen chloride (HCL) solution is preferably stirred for a certain time.

Step c) may include adding the initiator drop by drop with constant stirring after the solution is uniformly mixed. The initiator is not limited thereto, but ammonium persulfate (APS) is preferred.

Such chemical oxidation polymerization may include a one-pot process, and through the chemical oxidation polymerization, intense bubbles and color change may be observed.

After the chemical oxidation polymerization, the precipitate PFDA may be washed with hydrogen chloride (HCL), and then dried. It is preferable to perform at room temperature during the drying.

The present invention also provides a method for preparing poly (4,4'-9-fluorenylidene dianiline) (PFDA) nanostructures. More specifically in the presence of a surfactant,

a) dissolving 4-4'-9-fluorenylidene dianiline (FDA) in hydrogen chloride (HCL);

b) stirring the solution;

c) adding an initiator;

It provides a method for preparing a poly (4,4'-9-fluorenylidene dianiline) (PFDA) nanostructure by the chemical oxidative polymerization (FDA) of the FDA comprising a.

The surfactant is not limited thereto, but cetyltrimethyl ammonium bromide (CTAB) is preferable.

In step b), it is preferable to stir a 4-4'-9-fluorenylidene dianiline (FDA) solution of hydrogen chloride (HCL) for a predetermined time.

Step c) may include adding the initiator drop by drop with constant stirring after the solution is uniformly mixed. The initiator is not limited thereto, but ammonium persulfate (APS) is preferred.

Such chemical oxidation polymerization may include a one-pot process, and through the chemical oxidation polymerization, intense bubbles and color change may be observed.

After the chemical oxidation polymerization, the precipitate PFDA may be washed with hydrogen chloride (HCL), and then dried. It is preferable to perform at room temperature during the drying.

In the method for producing a poly (4,4'-9-fluorenylidene dianiline) (PFDA) and a poly (4,4'-9-fluorenylidene dianiline) (PFDA) nanostructures, 4-4 It can be prepared with varying molar ratios of '-9-fluorenylidene dianiline (FDA) to ammonium persulfate (APS). It is preferable that the molar ratio of said 4-4'-9-fluorenylidene dianiline (FDA) to ammonium persulfate (APS) is 1: 1.

The present invention also provides poly (4,4'-9-fluorenylidene dianiline) (PFDA) and poly (4,4'-9-fluorenylidene dianiline) (PFDA) prepared by the above method. ) Provides a nanostructure. The poly (4,4'-9-fluorenylidene dianiline) (PFDA) and poly (4,4'-9-fluorenylidene dianiline) (PFDA) nanostructures are in the form of: A) gap electronic materials, ii) green emission characteristics in LEDs, iii) absorption characteristics in the visible and infrared regions, iii) electron conversion for sensors in electrochemistry, iii) biomolecular functionalization, and enzyme immobilization capabilities. Applications include bars, solar cells, fuel cell catalysts and biosensors.

PFDA has the ability to biomolecule functionalization and enzymatic immobilization, excellent electron conversion for electrochemical sensors, low band gap electronic materials, good emission characteristics that emit green light in LEDs, visible and infrared regions of the solar spectrum. In order to improve the absorption characteristics, it includes an adjustable electronic band, which can be applied to solar cells, fuel cell catalysts and biosensors.

FIG. 1A is a FESEM image of PFDA and FIG. 1B is a neutralized PFDA.
FIG. 2A is a low magnification FIG. 2B is a FESEM image of PFDA at high magnification.
3A is a FESEM image in which CTAB of PFDA is negative and FIG. 3B is CTAB.
4 is a wide angle XRD pattern of (a) PFDA and (b) neutralized PFDA.
5 is the FTIR spectra of (a) PFDA and (b) neutralized PFDA.
6 is a UV-visible spectrum of (a) PFDA and (b) neutralized PFDA.
Figure 7 (a) is a cyclic voltammograms (CVs) of the cast solution of PFDA, 7 (b) is a PFDA in acetonitrile 0.1 M tetrabutyl ammonium bromide solution Solution (scan rate 50 mV / s).
FIG. 8 shows the change of (αhλ) ² vs hλ in (A) PL spectra of PFDA and (B) PFDA.

Hereinafter, the present invention will be described in more detail by way of examples. However, the following examples are illustrative of the present invention, and the content of the present invention is not limited by the examples.

≪ Example 1 >

1.1 Chemicals

4,4'-9-fluorenylidene dianiline (FDA), ammonium persulfate (APS) (99%), hydrocholoric acid, DMF (N, N'-dimethylformamide) and cetyltrimethylammonium bromide (Cetyltrimethyl ammonium bromide) was obtained from reagent grade, Sigma-Aldrich, Inc., USA.

1.2 Preparation of Poly (4,4'-9-fluorenylidene dianiline) (PFDA)

PFDA (bulk) and PFDA nanostructures were prepared by FDA chemical oxidation polymerization using APS as an initiator. For the preparation of PFDA (bulk), 40 mL of the FDA was dissolved in 100 mL of 1M HCl and the solution was stirred for 3 hours. After homogeneous mixing, 10 mM APS solution was added dropwise through constant stirring for 2 hours. The overall configuration was maintained to stir at room temperature for about 24 hours. Violent bubbles were observed after the process of chemical oxidation, followed by a color change from solidified white to green. The precipitate, PFDA, was washed with 1M HCL (3-4 times) and dried at room temperature.

 PFDA nanostructures were prepared by carrying out a polymerization reaction of the FDA similar to PFDA (bulk) in the presence of CTAB (surfactant).

1.3 Instruments

The structure of PFDA was observed by high voltage transition electron microscopy (HVTEM). Samples for observation of HVTEM were prepared by the following procedure; Samples were dispersed in ethanol by sonication and the dispersion was dropped onto a copper grid. Morphology was observed with HVTEM (JEM-ARM 1300s) under a field emission scanning electron microscope operated at 1250 kV. The morphology of the samples was also observed with a field emission scanning electron microscope (FESEM) (TEOL JSM-5600LV). Samples were mounted on a sample study and sputtered with a platinum thin layer prior to observation. Images of the FESEM were obtained at an accelerated voltage of 15 kV. An X-ray diffractometer (XRD) (Bruker AXS D8-Advanced diffractometer, UK) was used to characterize the pattern of the XRD of the sample with nickel using Cu Kα radiation (λ = 1.5406 A °). At room temperature at 4˚ scan rate for wide angle XRD analysis, continuous scan mode was used to collect 80˚ from 2θ data 10. Fourier Transform Infrared Spectrometer (FTIR) (Bruker IFS 66v FTIR) was used to measure the spectra of polymers using KBr pellets. The thermal stability (TGDTG) (Seiko, TMA 120, Japan) of the sample was attributed to a heating rate of 10 ° C / min under nitrogen gas at a temperature in the range of 30-800 ° C. Using UV / Vis Spectrometer and quartz cuvettes 0.2 cm at room temperature, the UV-Visible-visible absorption spectra was measured at wavelengths in the 300-800 nm range. Elemental analysis (Carlo, Erba1106, USA) was performed by finding out the percentage of gold present in the PFDA. Cyclic voltammetrics were measured using IVIUMSTAT electrochemistry (Netherlands). Experiments were conducted in quartz cuvettes, cells with indium tin oxide (ITO) as a working electrode (specific surface resistance about 10Ω, Corning Inc., USA), Ag / AgCl as reference electrode. (KClsat) (Princeton, USA), and using platinum wire as counter electrode.

1.4 Experimental Results

1.4.1 Mode (Morohology)

Simple one-pot chemical oxidation polymerization was used for the preparation of PFDA. PFDA was neutralized to remove dopant and convert to insulator foam. FIG. 1 shows FESEM images of (a) PFDA and (b) neutralized PFDA. FESEM images of PFDA prepared with CTAB showed a nanobelt type morphology with a width in the range of ~ 100 to 250 nm and several micrometers in length. It is worth noting that the shape of the polymer is not affected by the neutralization process. Figure 1 b shows the nanobelt structure for the form of neutralized PFDA (PFDA is treated like ammonia water). 2 (a and b) show FESEM images of PFDA and neutralized PFDA at different magnifications. The presence of the nanobelt was clearly visible . The belts were firm and straight. The image of HVTEM of PFDA also shows that it is a nanostructure. By comparing PFDA and neutralized PFDA, it was found that conversion from insulator foam to semiconductor foam was possible.

1.4.2 Influence of molar ratio

Morphological changes in PFDA were investigated with varying molar ratios of monomer (FDA) to oxidant (APS). When the molar ratio of APS was different in PFDA, the particles of PFDA showed a large crystal size in the range of ˜1 to 2 μm. PFDA showed a nanobelt when the ratio of monomer and oxidant was 1: 1. The nanobelts were found to clump together with a monomer to oxidant ratio of more than 1: 1.

1.4.3 Effect of Surfactants

The presence of surfactant (CTAB) had a profound effect on the form of PFDA. Images of the FESEM of PFDA in the presence and absence of CTAB were compared (FIGS. 3A, B). Highly aggregated bulk of PFDA was observed in the absence of CTAB (FIG. 3A). However, in the presence of CTAB, PFDA showed the shape of a nanobelt.

1.4.4 Analysis of the Elements

In order to determine the components present in the PFDA, energy dispersive X-ray analysis (EDXA) was performed. Samples were oxidized at 900 ° C under static conditions in an environment with pure oxygen. This was to produce a mixture of gases carbon dioxide, carbon monoxide, water, nitrogen elements and nitrogen oxides. PFDA consisted of 80% carbon, 15.46% oxygen, 0.77% sulfur, 3.11% chlorine and 0.66% bromine.

1.4.5 X-ray diffraction (XRD) analysis

A wide angle XRD pattern (a) of PFDA and a neutralized PFDA (b) are shown in FIG. 4. The initial and neutralized structure of the PFDA sample shows crystallized peaks at 2θ = 14.2 °, 21.7 °, 26.5 °, 27.2 ° and 29.1 °, which represent (011), (020), (200), (121) and ( 022), which is consistent with the PFDA refraction [HK Chaudhari, DS Kelkar, Polym. Int. 1997, 42, 380]. The centers of the two broad peaks, 2θ = 21.7 ° and 26.5 °, were due to the parallel and vertical periodicity of the polyaniline (PANI) units in the polymer chain, respectively [YB Moon, Y. Cao, P. Smith, A. Heeger, J. Polym. Commun. 1989,30,543].

1.4.6 Structural Studies

The band at ˜3410 cm ⁻¹ coincided with the NH stretching vibration of the initial aromatic amine in PFDA (FIG. 5). In general, ring stretching vibrations of bands matching C = N and C = C are about 1500 and 1445, respectively. observed at cm ⁻¹ . The relative intensities of these bands represent units of quinoids and benzenoids [S. Tan, D. Belanger, J.Phys.Chem.B 2005, 109, 23480; S.Tung, B.Hwang, J.Membr.Sci. 2004, 241, 315]. Neutralized PFDA also means a characteristic band of PANI units, but 1510 and 1460 There was a change in the position of the vibrational bands of cm ^-1 between benzenoid and quinoid C = N.

1.4.7 UV-visible research

FIG. 6 means UV-visible spectra of PFDA (a) and neutralized PFDA (b). The PFDA spectra show two peaks at the center points 380 nm and 540 nm. After neutralization, the long absorption band shifted to 550 nm. Electrical bands of about 380 nm and 540 nm were assigned to the π-π * polaron excitation transition and the exciton transition of the quinoid rings of the PANI chain, respectively. MW Xia, AG MacDiarmid, Chem. Mater., 1995 , 7 , 443. The UV-visible spectrum of the PFDA means that the PANI units in the PFDA have different electrical bands than the PNAI signature of a typical PANI. There are two prominent electrical features for PFDA, suggesting that the PANI in the PFDA exhibits a different arrangement than the typical PANI. For PFDA, π-π * transition bands were observed at 380 nm. However, in the case of PANI, the π-π * transition band generally appears at 320 nm [JEDAlbuquerque, LHC Mattoso, RM Fariac, JG Masters, A. G. MacDiarmid, Synth.Met., 2004, 146, 1]. The red shift in the π-π * transition of PFDA is consistent with the longer chain length of the aniline units in PFDA.

1.4.8 Thermal Study

The TG curves of the two samples in the thermogravimetric curve (TG) of PFDA (a) and neutralized PFDA (b) showed two stages of weight loss. The weight changes after 200 ° C. for the doped samples showed a significant decrease (almost 25%). This weight change is consistent with the removal of dopant ions. Thus, the PANI chains in the PFDA are effectively doped.

1.4.9 Electrochemical characteristics

Cyclic voltammetry was used to investigate the redox reactions associated with conductive polymers [A.G. MacDiarmid, W. Zheng, MRS Bull. 221997.24]. 7 shows a film of PFDA on an electrode of platinum recorded in typical cyclic voltammograms (CVs).

Fig. 7 (a) shows the cyclic voltammograms (CVs) of the cast solution of PFDA, three oxidation peaks (anode) -0.95V, 0.88 and 1.35V and two reduction peaks (cathode) about 0.75 V, 0.85 and C3 = 1.22. Similarly, Figure 7 (b) shows that the three oxidation peaks (anode) of the solution of PFDA in acetonitrile are -0.69 V, 0.64 V and 1.37 V, and the two reduction peaks (cathode) are about -0.4 V, It could be seen at 0.49V and 1.39V. The more positive oxidation peaks matched the PANI units in the PFDA and the lower positive and negative peaks matched the PFDA units. In addition, PFDA can be n-doped, as can be clearly seen from the reduction peak at negative potential. Thus, there can be dual electric band systems in the same polymer backbone structures. PFDA can be thought of as a polymer with adjustable electrical bands. In addition, these bands can affect the luminescent characteristics of PFDA.

1.4.10 Luminescent Features

8A shows the photoluminescence (PL) spectra of PFDA. The emission peaks of 430 nm and 550 nm in the PL spectrum were in agreement with the blue and green emission characteristics of PFDA, respectively.

1.4.11 Optical Properties

The optical band gap is calculated by using the following equation.

Where Eg is the energy gap between the bottom of the conduction band and the top of the valence band, α is the absorption coefficient, hλ is the photon energy, n is the direct transition and two indirect It is the same coefficient as the transition. The change in (αhλ) ² vs hλ in PFDA is shown. The optical band gap was estimated from the linear portion of the graph showing (αhλ) ² = 0 and determined. PFDA represents three optical transitions with band gaps around 1.91, 2.82, and 3.40 eV shown in FIG. 8B. The optical band gap of PFDA is larger than that of other polyanilines [F. Yakuphanoglu, E. Basaran, BF Su enkal, E. Sezer, J. Phys. Chem. B 2006, 110, 16908-16913, Mukherjee, AK; Menon, R. Pramana J. Phys. 2002, 58, 233.

Claims (10)

a) dissolving 4-4'-9-fluorenylidene dianiline (FDA) in hydrogen chloride;
b) stirring the solution;
c) adding an initiator;
Method for producing a poly (4,4'-9-fluorenylidene dianiline) (PFDA) by the chemical oxidation polymerization of the FDA comprising a. A process according to claim 1 which is prepared in the presence of a surfactant. The method of claim 2, wherein the surfactant is cetyltrimethyl ammonium bromide (CTAB). The process according to claim 1 or 2, wherein the initiator is ammonium persulfate (APS). 5. The process according to claim 4, wherein the molar ratio of ammonium persulfate to 4-4′-9-fluorenylidene dianiline (FDA) is varied. 6. A process according to claim 5, wherein the molar ratio of ammonium persulfate to 4-4'-9-fluorenylidene dianiline (FDA) is 1: 1. The process according to claim 1 or 2, wherein the chemical oxidation polymerization is a one-pot process. Poly (4,4'-9-fluorenylidene dianiline) (PFDA) prepared by claim 1. A poly (4,4'-9-fluorenylidene dianiline) (PFDA) nanostructure prepared by claim 2. The poly (4,4'-9-fluorenylidene dianiline) (PFDA) according to claim 8 or 9, having one or more of the following properties.
Iii) a low band gap electronic material,
Ii) green emitting characteristics in LEDs,
Iii) absorption characteristics in the visible and infrared ranges in solar cell applications,
Iv) electron conversion in electrochemical sensors,
Iii) biomolecular functionalization and enzyme immobilization ability

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