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TiO2 composites by chemical oxidative method
Optik 124 (2013) 1089–1091
Contents lists available at SciVerse ScienceDirect
Optik journal homepage: www.elsevier.de/ijleo
Synthesis and characterization of polypyrrole/TiO2 composites by chemical oxidative method S. Deivanayaki, V. Ponnuswamy ∗ , R. Mariappan, P. Jayamurugan Department of Physics, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore-641 020, Tamil Nadu, India
a r t i c l e
i n f o
Article history: Received 7 June 2011 Accepted 27 February 2012
Keywords: Polypyrrole–TiO2 composites FTIR X-ray diffraction SEM NLO UV
a b s t r a c t Synthesis of polypyrrole and polypyrrole/TiO2 composites samples using chemical oxidative method at room temperature with various dopant percentages of TiO2 . The samples were characterized by UV–vis spectrometer, Fourier transmittance infra red (FTIR) spectrometer, X-ray diffraction (XRD), Scanning electron microscopy (SEM) and non linear optics (NLO) studies. Optical spectra reveal the absorbance band at 250 nm represents the characteristic peak of TiO2 particles. The second band is shifted at 300 nm with –* transition. FTIR confirms the presence of TiO2 in the molecular structure. The intensity of peaks found to be decreased with the increase of TiO2 content. A small band at 1699 cm−1 and 1107 cm−1 corresponds to Ti–O–C stretching mode in each case. This band indicates the formation of polypyrrole/TiO2 composites. XRD patterns reveal the samples were polycrystalline nature with tetragonal structure and (1 0 1) plane as preferential orientation. SEM studies reveal the formation of uniform granular morphology with average grain size of ∼0.4 m for (50%) TiO2 sample. NLO studies reveal that the polypyrrole and polypyrrole/TiO2 composites possess non-linear optical properties. © 2012 Elsevier GmbH. All rights reserved.
1. Introduction Conducting polymer/inorganic composites have been considered as new class of materials due to their improved properties compared with those of pure conducting polymers or inorganic materials [1]. Recently, with the advent of newer technologies, composite materials based on organic and inorganic components have been focus of chemists and physicists. This is due to their novel properties connected to the combination of extremely different materials at the molecular level [2,3]. These hybrid materials are most promising for the fabrication of electronic devices that assimilate superior electronic, magnetic and optical properties [4–7]. Among polyaniline, polypyrrole and polythiophene, polypyrrole has attracted much attention owing to its unique electrical conductivity, redox property, excellent environmental stability, as well as the virtue of easy preparation by both chemical and electro chemical approaches [8]. TiO2 is an excellent wave-transmitting material, which can widen the frequency bandwidth of microwave absorber. It has low density, high specific surface area, superior delivering ability and low cost [9]. The organic polymers are considered to be promising materials, mainly because they offer many advantages such as large and stable NLO response, light weight, high optical quality, chemical resistance and good process ability to form optical
devices [10–12]. The electron density of A-conjugated system plays a major role in determining NLO response properties. In the present work, polypyrrole/TiO2 composites were synthesized by chemical oxidative method at room temperature with different weight percentages of TiO2 . The nonlinear, structural and morphological of polypyrrole/TiO2 composites were investigated. 2. Experimental 2.1. Synthesis of polypyrrole 0.1 M of pyrrole was dissolved in 100 ml of de-ionized water and stirred for 15 min using a magnetic stirrer. 0.5 M of H2 SO4 was added slowly from drop to the pyrrole monomer solution. 0.1 M of ammonium per sulphate was dissolved in 100 ml of deionized water and slowly added drop by drop for half an hour from a burette vertically to the above prepared solution. After stirring for 4 h, the solution was filtered and the residual was washed with double distilled water, methanol and acetone, and then dried in an oven at 60 ◦ C. Subsequently the product is grinded to get powder of polypyrrole. The emaraldine base form of this PPy was formed by stirring with ammonia for 2 h, and then washed, dried and powdered. 2.2. Synthesis of polypyrrole/TiO2 composites
∗ Corresponding author. Tel.: +91 422 2692461; fax: +91 422 2693812. E-mail addresses: [email protected] (S. Deivanayaki), [email protected] (V. Ponnuswamy). 0030-4026/$ – see front matter © 2012 Elsevier GmbH. All rights reserved. doi:10.1016/j.ijleo.2012.02.029
0.1 M of pyrrole and 1 M of H2 SO4 were stirred with double distilled water and further with 30% weight of TiO2 with respect to the
1090
S. Deivanayaki et al. / Optik 124 (2013) 1089–1091
Fig. 1. XRD patterns of polypyrrole/TiO2 composites: (a) PPy, (b) 30%, (c) 40% and (d) 50%.
pyrrole. 0.1 M of ammonium per sulphate was dissolved in 100 ml of de-ionized water and slowly added drop by drop for half an hour from a burette vertically to the above prepared solution. After stirring for 4 h, the solution was filtered and the residual was washed with double distilled water, methanol and acetone, and then dried in an oven at 60 ◦ C. This was grinded into powder. The same process was continued with 40% and 50% weight of TiO2 with respect to pyrrole monomer. 3. Results and discussion The polypyrrole and PPy/TiO2 composites with different weight percentages at 30%, 40% and 50% were synthesized using sulphuric acid (H2 SO4 ) by chemical oxidation method. The polymer samples obtained were powdery. It was characterized by Fourier transform infrared spectroscopy (FTIR), UV–visible spectroscopy, X-ray diffraction, scanning electron microscope (SEM) and NLO studies. The results are discussed. 3.1. XRD analysis of PPy and PPy/TiO2 composites X-ray diffraction patterns of (PPy/TiO2 ) composites sample were obtained using advance diffractometer (for 2 range from 10◦ to ˚ to identify 80◦ ) with monochromatic CuK␣ radiation ( = 1.54 A) crystalline nature of the samples. XRD patterns of polypyrrole and polypyrrole/titanium dioxide (PPy/TiO2 ) composites with different weight percentages (30%, 40% and 50%) are shown in Fig. 1a–d. It is observed that Fig. 1a shows amorphous nature. As the TiO2 percentage was increased the amorphous nature disappeared and the films became more strongly oriented along the (1 0 1) direction. From Fig. 1b–c, the all films were polycrystalline nature with tetragonal structure with its most intense peak located at 25.3◦ , which corresponds to the preferred growth orientation (1 0 1) plane. The different peaks in the diffractogram were indexed and the corresponding values of interplanar spacing ‘d’ were calculated and compared with the standard (JCPDS card no. 89-4921). The peaks around 25.3◦ , 37.8◦ , 48.1◦ , 53.9◦ , 55.1◦ , 62.8◦ , 68.8◦ , 70.4◦ .and 75.2◦ correspond to (1 0 1), (0 0 4), (2 0 0), (1 0 5), (2 1 1), (2 0 4), (1 1 6), (2 2 0) and (2 1 5) plane values. The peak intensity increases with increasing in the TiO2 percentage, which is due to the strong effect of the TiO2 samples.
Fig. 2. SEM images of polypyrrole/TiO2 composites: (a) polypyrrole, (b) 30%, (c) 40% and (d) 50%.
The crystallite size of the Debye–Scherrer formula [13]. D=
samples
is
evaluated
k ˇ cos
by
(1)
where k is the shape factor, D is the crystallite size, is the diffraction angle, ˇ is the full width half maximum of diffraction angles in radians. The average crystallite size was determined using Scherer formula and was estimated to be around 55 nm as calculated from the peak related to (1 0 1) plane for 50% of TiO2 sample. 3.2. SEM analysis of PPy/TiO2 composites Scanning electron microscopy (SEM) analysis was done using SEM JSM.6400 JEOL scanning microscope. Fig. 2a–d shows the SEM images of PPy/TiO2 composites with different weight percentages of 30%, 40%, and 50%. It is observed that (Fig. 2b) the PPy/TiO2 sample has an irregular granular morphology and the average grain size is ∼0.4 m. When the increases of TiO2 percentage has the surface morphology strongly effect and uniform homogeneous distribution and increasing the average grain size is ∼0.5 m for 50% of TiO2 samples. SEM study confirms the morphology transformation from polypyrrole to polypyrrole/TiO2 composites. 3.3. FTIR analysis of polypyrrole and PPy/TiO2 composites FTIR spectroscopy analysis was scanned from 4000 to 400 cm−1 using thermonicolet V-200 FTIR Spectrometer by KBr pellet technique. Fig. 3a–d shows the FTIR spectra of polypyrrole and PPy/TiO2 composites with different weight percentages of TiO2 . The N H stretching, C H stretching, C C stretching, C N stretching, C H in plane bending and C H out plane bending corresponds to 3428 cm−1 , 2300 cm−1 , 1311 cm−1 , 1552 cm−1 , 1183 cm−1 , 1042 cm−1 , 915 cm−1 and 787 cm−1 respectively. Fig. 3b–d of PPy/TiO2 composites indicate that the N H, C H, C C, and C N stretching are shifted slightly. With the increase of TiO2 content, the intensity of each peak is found to be decreasing. A small band at 1699 cm−1 and 1107 cm−1 corresponds to Ti O C stretching mode in each case [14]. The FTIR study confirms that the TiO2 molecules are well incorporated with polypyrrole structure.
S. Deivanayaki et al. / Optik 124 (2013) 1089–1091
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of PPy/TiO2 composites was densely packed in capillary tubes and the input pulse energy of 1.8 m/p was made to incident on PPy/TiO2 composites. KDP was used as a reference material. The PPy/TiO2 composites with various weight percentages (30%, 40% and 50%) were tested. These values are 31mv, 33mv, 36mv which exceeds 5 times than KDP (6mv), signifying that PPy/TiO2 composites possess nonlinear optical properties. 4. Conclusion The FTIR study confirms that the TiO2 molecules are well combined with polypyrrole structure. When TiO2 content is increased, the intensity of each peak is found to be decreased. A small band at 1699 cm−1 and 1107 cm−1 corresponds to Ti O C stretching mode in each case. SEM studies confirm the morphology transformation of the TiO2 doped Pyrrole compared with PPy. The band at 250 nm represents the characteristic peak of TiO2 . The second band is shifted at 300 nm with –* transition. This band indicates the formation of PPy/TiO2 composites. The presence of NLO properties has been confirmed. References
Fig. 3. FTIR spectra of polypyrrole/TiO2 composites: (a) polypyrrole, (b) 30%, (c) 40% and (d) 50%.
Fig. 4. UV spectrum of polypyrrole/TiO2 composites: (a) polypyrrole, (b) 30%, (c) 40% and (d) 50%.
3.4. Optical properties of polypyrrole and PPy/TiO2 composites The UV–visible spectra of (PPy/TiO2 ) samples were recorded employing Jusco V-530 dual beam spectrometer in m-cresol solvent with the wavelength range 200–800 nm. UV–vis absorption spectra of PPy and PPy/TiO2 composites are shown in Fig. 4a–d. The band at 250 nm represents the characteristic peak of TiO2 particles. The second band is shifted at 300 nm with –* transition and excitation moment of polaron. This band indicates the formation of PPy/TiO2 composites [15]. 3.5. NLO studies The second harmonic generation of the synthesized PPy/TiO2 composites was studied using powder technique. The powder form
[1] Rupali Gangopadhyay, Amitabha Be, Conducting Polymer Nanocomposites: A Brief Overview, Chemistry of materials 12 (2000) 608–622. [2] Xiaomeng Sui, Ying Chu, Shuangxi Xing, Chengzhan Liu, Synthesis of PANI/AgCl, PANI/BaSO4 and PANI/TiO2 nanocomposites in CTAB/hexanol/water reverse micelle, Mater. Lett. 58 (2004) 1255–1259. [3] M.V. Murugendrappa, Ameena Parveen, M.V.N. Ambika Prasad, Synthesis, characterization and ac conductivity studies of polypyrrole–vanadium pentaoxide composites, Mater. Sci. Eng. A 459 (2007) 371–374. [4] Jiu Tonggang, Liu Huibiao, Gan Haiyang, Li Yuliang, Xiao Shengqiang, Li Hongmei, Liu Yang, Lu Fushen, Jiang Lei, Zhu Daoben, A new class of approach for hybrid inorganic/organic materials containing semiconductor ZnO, Synth. Met. 148 (2005) 313–319. [5] P. Alivisatos, Semiconductor clusters, nanocrystals, and quantum dots, Science 271 (1996) 933–937. [6] H. Rein, K. Ruckpaul, W. Haberditzl, Magneto-optical rotation studies on various porphyrin derivatives. Hemin complexes, and complexes of methemoglobin, Chem. Phys. Lett. 20 (1973) 71–76. [7] J.J.M. Halls, C.A. Walsh, N.C. Greenham, E.A. Marseglia, R.H. Friend, S.C. Moratti, A.B. Holmes, Efficient photodiodes from interpenetrating polymer networks, Nature 376 (1995) 498–500. [8] Yao Tongjie, Lin Quan, Zhang Kai, Zhao Dengfeng, Lv Hui, Zhang Junhu, Yang Bai, Preparation of SiO2 polystyrene@polypyrrole sandwich composites and hollow polypyrrole capsules with movable SiO2 spheres inside, J. Colloid Interface Sci. 315 (2007) 434–438. [9] Cunrui Zhang, Qiaoling Li, Jianqiang Li, Synthesis and characterization of polypyrrole/TiO2 composite by in situ polymerization method, Synth. Met. 160 (2010) 1699–1703. [10] Yuanjing Cui, Huasen Ren, Jiancan Yu, Zhiyu Wang, Qian Guodong, An indanone-based alkoxysilane dye with second order nonlinear optical properties, Dyes Pigments 81 (2009) 53–57. [11] Fengxian Qiu, Yuming Zhou, Juzheng Liu, Xuping Zhang, Preparation, morphological and thermal stability of polyimide/silica hybrid material containing dye NBDPA, Dyes Pigments 71 (2006) 37–42. [12] T.D. Kim, J. Luo, Y.J. Cheng, Z. Shi, S. Hau, S.H. Jang, X.H. Zhou, Y. Tian, B. Polishak, S. Huang, H. Ma, L.R. Dalton, A.K.Y. Jen, Binary chromophore systems in nonlinear optical dendrimers and polymers for large electro-optic activities, J. Phys. Chem. C 112 (2008) 8091–8098. [13] T. Mahalingam, S. Thanikaikarasan, V. Dhanasekaran, R. Mariappan, P. Jayamurugan, S. Velumani, Jin-Koo Rhee, Electrochemical deposition and studies on CdCr2 S4 thin films, Mater. Sci. Eng. B 174 (2010) 249–252. [14] S.H. Yang, T.P. Nguyen, P. Le Rendu, C.S. Hsu, Optical and electrical properties of PPV/SiO2 and PPV/TiO2 composite materials, Compos. Part A: Appl. Sci. Manuf. 36 (2005) 509–513. [15] M.G. Murali, M.G. Ramya, D. Udayakumar, N.B. Lakshmi, Reji Philip, Synthesis and third order optical nonlinearity studies of the donor–acceptor conjugated polymer, poly(2-[3,4-didodecyloxy-5-(1,3,4-oxadiazol-2-yl)thiophen-2-yl]-5phenyl-1,3,4-oxadiazole) and a polymer/TiO2 nanocomposite, Synth. Met. 160 (2010) 2520–2525.
Contents lists available at SciVerse ScienceDirect
Optik journal homepage: www.elsevier.de/ijleo
Synthesis and characterization of polypyrrole/TiO2 composites by chemical oxidative method S. Deivanayaki, V. Ponnuswamy ∗ , R. Mariappan, P. Jayamurugan Department of Physics, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore-641 020, Tamil Nadu, India
a r t i c l e
i n f o
Article history: Received 7 June 2011 Accepted 27 February 2012
Keywords: Polypyrrole–TiO2 composites FTIR X-ray diffraction SEM NLO UV
a b s t r a c t Synthesis of polypyrrole and polypyrrole/TiO2 composites samples using chemical oxidative method at room temperature with various dopant percentages of TiO2 . The samples were characterized by UV–vis spectrometer, Fourier transmittance infra red (FTIR) spectrometer, X-ray diffraction (XRD), Scanning electron microscopy (SEM) and non linear optics (NLO) studies. Optical spectra reveal the absorbance band at 250 nm represents the characteristic peak of TiO2 particles. The second band is shifted at 300 nm with –* transition. FTIR confirms the presence of TiO2 in the molecular structure. The intensity of peaks found to be decreased with the increase of TiO2 content. A small band at 1699 cm−1 and 1107 cm−1 corresponds to Ti–O–C stretching mode in each case. This band indicates the formation of polypyrrole/TiO2 composites. XRD patterns reveal the samples were polycrystalline nature with tetragonal structure and (1 0 1) plane as preferential orientation. SEM studies reveal the formation of uniform granular morphology with average grain size of ∼0.4 m for (50%) TiO2 sample. NLO studies reveal that the polypyrrole and polypyrrole/TiO2 composites possess non-linear optical properties. © 2012 Elsevier GmbH. All rights reserved.
1. Introduction Conducting polymer/inorganic composites have been considered as new class of materials due to their improved properties compared with those of pure conducting polymers or inorganic materials [1]. Recently, with the advent of newer technologies, composite materials based on organic and inorganic components have been focus of chemists and physicists. This is due to their novel properties connected to the combination of extremely different materials at the molecular level [2,3]. These hybrid materials are most promising for the fabrication of electronic devices that assimilate superior electronic, magnetic and optical properties [4–7]. Among polyaniline, polypyrrole and polythiophene, polypyrrole has attracted much attention owing to its unique electrical conductivity, redox property, excellent environmental stability, as well as the virtue of easy preparation by both chemical and electro chemical approaches [8]. TiO2 is an excellent wave-transmitting material, which can widen the frequency bandwidth of microwave absorber. It has low density, high specific surface area, superior delivering ability and low cost [9]. The organic polymers are considered to be promising materials, mainly because they offer many advantages such as large and stable NLO response, light weight, high optical quality, chemical resistance and good process ability to form optical
devices [10–12]. The electron density of A-conjugated system plays a major role in determining NLO response properties. In the present work, polypyrrole/TiO2 composites were synthesized by chemical oxidative method at room temperature with different weight percentages of TiO2 . The nonlinear, structural and morphological of polypyrrole/TiO2 composites were investigated. 2. Experimental 2.1. Synthesis of polypyrrole 0.1 M of pyrrole was dissolved in 100 ml of de-ionized water and stirred for 15 min using a magnetic stirrer. 0.5 M of H2 SO4 was added slowly from drop to the pyrrole monomer solution. 0.1 M of ammonium per sulphate was dissolved in 100 ml of deionized water and slowly added drop by drop for half an hour from a burette vertically to the above prepared solution. After stirring for 4 h, the solution was filtered and the residual was washed with double distilled water, methanol and acetone, and then dried in an oven at 60 ◦ C. Subsequently the product is grinded to get powder of polypyrrole. The emaraldine base form of this PPy was formed by stirring with ammonia for 2 h, and then washed, dried and powdered. 2.2. Synthesis of polypyrrole/TiO2 composites
∗ Corresponding author. Tel.: +91 422 2692461; fax: +91 422 2693812. E-mail addresses: [email protected] (S. Deivanayaki), [email protected] (V. Ponnuswamy). 0030-4026/$ – see front matter © 2012 Elsevier GmbH. All rights reserved. doi:10.1016/j.ijleo.2012.02.029
0.1 M of pyrrole and 1 M of H2 SO4 were stirred with double distilled water and further with 30% weight of TiO2 with respect to the
1090
S. Deivanayaki et al. / Optik 124 (2013) 1089–1091
Fig. 1. XRD patterns of polypyrrole/TiO2 composites: (a) PPy, (b) 30%, (c) 40% and (d) 50%.
pyrrole. 0.1 M of ammonium per sulphate was dissolved in 100 ml of de-ionized water and slowly added drop by drop for half an hour from a burette vertically to the above prepared solution. After stirring for 4 h, the solution was filtered and the residual was washed with double distilled water, methanol and acetone, and then dried in an oven at 60 ◦ C. This was grinded into powder. The same process was continued with 40% and 50% weight of TiO2 with respect to pyrrole monomer. 3. Results and discussion The polypyrrole and PPy/TiO2 composites with different weight percentages at 30%, 40% and 50% were synthesized using sulphuric acid (H2 SO4 ) by chemical oxidation method. The polymer samples obtained were powdery. It was characterized by Fourier transform infrared spectroscopy (FTIR), UV–visible spectroscopy, X-ray diffraction, scanning electron microscope (SEM) and NLO studies. The results are discussed. 3.1. XRD analysis of PPy and PPy/TiO2 composites X-ray diffraction patterns of (PPy/TiO2 ) composites sample were obtained using advance diffractometer (for 2 range from 10◦ to ˚ to identify 80◦ ) with monochromatic CuK␣ radiation ( = 1.54 A) crystalline nature of the samples. XRD patterns of polypyrrole and polypyrrole/titanium dioxide (PPy/TiO2 ) composites with different weight percentages (30%, 40% and 50%) are shown in Fig. 1a–d. It is observed that Fig. 1a shows amorphous nature. As the TiO2 percentage was increased the amorphous nature disappeared and the films became more strongly oriented along the (1 0 1) direction. From Fig. 1b–c, the all films were polycrystalline nature with tetragonal structure with its most intense peak located at 25.3◦ , which corresponds to the preferred growth orientation (1 0 1) plane. The different peaks in the diffractogram were indexed and the corresponding values of interplanar spacing ‘d’ were calculated and compared with the standard (JCPDS card no. 89-4921). The peaks around 25.3◦ , 37.8◦ , 48.1◦ , 53.9◦ , 55.1◦ , 62.8◦ , 68.8◦ , 70.4◦ .and 75.2◦ correspond to (1 0 1), (0 0 4), (2 0 0), (1 0 5), (2 1 1), (2 0 4), (1 1 6), (2 2 0) and (2 1 5) plane values. The peak intensity increases with increasing in the TiO2 percentage, which is due to the strong effect of the TiO2 samples.
Fig. 2. SEM images of polypyrrole/TiO2 composites: (a) polypyrrole, (b) 30%, (c) 40% and (d) 50%.
The crystallite size of the Debye–Scherrer formula [13]. D=
samples
is
evaluated
k ˇ cos
by
(1)
where k is the shape factor, D is the crystallite size, is the diffraction angle, ˇ is the full width half maximum of diffraction angles in radians. The average crystallite size was determined using Scherer formula and was estimated to be around 55 nm as calculated from the peak related to (1 0 1) plane for 50% of TiO2 sample. 3.2. SEM analysis of PPy/TiO2 composites Scanning electron microscopy (SEM) analysis was done using SEM JSM.6400 JEOL scanning microscope. Fig. 2a–d shows the SEM images of PPy/TiO2 composites with different weight percentages of 30%, 40%, and 50%. It is observed that (Fig. 2b) the PPy/TiO2 sample has an irregular granular morphology and the average grain size is ∼0.4 m. When the increases of TiO2 percentage has the surface morphology strongly effect and uniform homogeneous distribution and increasing the average grain size is ∼0.5 m for 50% of TiO2 samples. SEM study confirms the morphology transformation from polypyrrole to polypyrrole/TiO2 composites. 3.3. FTIR analysis of polypyrrole and PPy/TiO2 composites FTIR spectroscopy analysis was scanned from 4000 to 400 cm−1 using thermonicolet V-200 FTIR Spectrometer by KBr pellet technique. Fig. 3a–d shows the FTIR spectra of polypyrrole and PPy/TiO2 composites with different weight percentages of TiO2 . The N H stretching, C H stretching, C C stretching, C N stretching, C H in plane bending and C H out plane bending corresponds to 3428 cm−1 , 2300 cm−1 , 1311 cm−1 , 1552 cm−1 , 1183 cm−1 , 1042 cm−1 , 915 cm−1 and 787 cm−1 respectively. Fig. 3b–d of PPy/TiO2 composites indicate that the N H, C H, C C, and C N stretching are shifted slightly. With the increase of TiO2 content, the intensity of each peak is found to be decreasing. A small band at 1699 cm−1 and 1107 cm−1 corresponds to Ti O C stretching mode in each case [14]. The FTIR study confirms that the TiO2 molecules are well incorporated with polypyrrole structure.
S. Deivanayaki et al. / Optik 124 (2013) 1089–1091
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of PPy/TiO2 composites was densely packed in capillary tubes and the input pulse energy of 1.8 m/p was made to incident on PPy/TiO2 composites. KDP was used as a reference material. The PPy/TiO2 composites with various weight percentages (30%, 40% and 50%) were tested. These values are 31mv, 33mv, 36mv which exceeds 5 times than KDP (6mv), signifying that PPy/TiO2 composites possess nonlinear optical properties. 4. Conclusion The FTIR study confirms that the TiO2 molecules are well combined with polypyrrole structure. When TiO2 content is increased, the intensity of each peak is found to be decreased. A small band at 1699 cm−1 and 1107 cm−1 corresponds to Ti O C stretching mode in each case. SEM studies confirm the morphology transformation of the TiO2 doped Pyrrole compared with PPy. The band at 250 nm represents the characteristic peak of TiO2 . The second band is shifted at 300 nm with –* transition. This band indicates the formation of PPy/TiO2 composites. The presence of NLO properties has been confirmed. References
Fig. 3. FTIR spectra of polypyrrole/TiO2 composites: (a) polypyrrole, (b) 30%, (c) 40% and (d) 50%.
Fig. 4. UV spectrum of polypyrrole/TiO2 composites: (a) polypyrrole, (b) 30%, (c) 40% and (d) 50%.
3.4. Optical properties of polypyrrole and PPy/TiO2 composites The UV–visible spectra of (PPy/TiO2 ) samples were recorded employing Jusco V-530 dual beam spectrometer in m-cresol solvent with the wavelength range 200–800 nm. UV–vis absorption spectra of PPy and PPy/TiO2 composites are shown in Fig. 4a–d. The band at 250 nm represents the characteristic peak of TiO2 particles. The second band is shifted at 300 nm with –* transition and excitation moment of polaron. This band indicates the formation of PPy/TiO2 composites [15]. 3.5. NLO studies The second harmonic generation of the synthesized PPy/TiO2 composites was studied using powder technique. The powder form
[1] Rupali Gangopadhyay, Amitabha Be, Conducting Polymer Nanocomposites: A Brief Overview, Chemistry of materials 12 (2000) 608–622. [2] Xiaomeng Sui, Ying Chu, Shuangxi Xing, Chengzhan Liu, Synthesis of PANI/AgCl, PANI/BaSO4 and PANI/TiO2 nanocomposites in CTAB/hexanol/water reverse micelle, Mater. Lett. 58 (2004) 1255–1259. [3] M.V. Murugendrappa, Ameena Parveen, M.V.N. Ambika Prasad, Synthesis, characterization and ac conductivity studies of polypyrrole–vanadium pentaoxide composites, Mater. Sci. Eng. A 459 (2007) 371–374. [4] Jiu Tonggang, Liu Huibiao, Gan Haiyang, Li Yuliang, Xiao Shengqiang, Li Hongmei, Liu Yang, Lu Fushen, Jiang Lei, Zhu Daoben, A new class of approach for hybrid inorganic/organic materials containing semiconductor ZnO, Synth. Met. 148 (2005) 313–319. [5] P. Alivisatos, Semiconductor clusters, nanocrystals, and quantum dots, Science 271 (1996) 933–937. [6] H. Rein, K. Ruckpaul, W. Haberditzl, Magneto-optical rotation studies on various porphyrin derivatives. Hemin complexes, and complexes of methemoglobin, Chem. Phys. Lett. 20 (1973) 71–76. [7] J.J.M. Halls, C.A. Walsh, N.C. Greenham, E.A. Marseglia, R.H. Friend, S.C. Moratti, A.B. Holmes, Efficient photodiodes from interpenetrating polymer networks, Nature 376 (1995) 498–500. [8] Yao Tongjie, Lin Quan, Zhang Kai, Zhao Dengfeng, Lv Hui, Zhang Junhu, Yang Bai, Preparation of SiO2 polystyrene@polypyrrole sandwich composites and hollow polypyrrole capsules with movable SiO2 spheres inside, J. Colloid Interface Sci. 315 (2007) 434–438. [9] Cunrui Zhang, Qiaoling Li, Jianqiang Li, Synthesis and characterization of polypyrrole/TiO2 composite by in situ polymerization method, Synth. Met. 160 (2010) 1699–1703. [10] Yuanjing Cui, Huasen Ren, Jiancan Yu, Zhiyu Wang, Qian Guodong, An indanone-based alkoxysilane dye with second order nonlinear optical properties, Dyes Pigments 81 (2009) 53–57. [11] Fengxian Qiu, Yuming Zhou, Juzheng Liu, Xuping Zhang, Preparation, morphological and thermal stability of polyimide/silica hybrid material containing dye NBDPA, Dyes Pigments 71 (2006) 37–42. [12] T.D. Kim, J. Luo, Y.J. Cheng, Z. Shi, S. Hau, S.H. Jang, X.H. Zhou, Y. Tian, B. Polishak, S. Huang, H. Ma, L.R. Dalton, A.K.Y. Jen, Binary chromophore systems in nonlinear optical dendrimers and polymers for large electro-optic activities, J. Phys. Chem. C 112 (2008) 8091–8098. [13] T. Mahalingam, S. Thanikaikarasan, V. Dhanasekaran, R. Mariappan, P. Jayamurugan, S. Velumani, Jin-Koo Rhee, Electrochemical deposition and studies on CdCr2 S4 thin films, Mater. Sci. Eng. B 174 (2010) 249–252. [14] S.H. Yang, T.P. Nguyen, P. Le Rendu, C.S. Hsu, Optical and electrical properties of PPV/SiO2 and PPV/TiO2 composite materials, Compos. Part A: Appl. Sci. Manuf. 36 (2005) 509–513. [15] M.G. Murali, M.G. Ramya, D. Udayakumar, N.B. Lakshmi, Reji Philip, Synthesis and third order optical nonlinearity studies of the donor–acceptor conjugated polymer, poly(2-[3,4-didodecyloxy-5-(1,3,4-oxadiazol-2-yl)thiophen-2-yl]-5phenyl-1,3,4-oxadiazole) and a polymer/TiO2 nanocomposite, Synth. Met. 160 (2010) 2520–2525.