Synthesis and Characterization of Various Acid Doped Polyaniline Nanofibers

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 04 Issue: 09 | Sep -2017 www.irjet.net p-ISSN: 2395-0072

Synthesis and characterization of various acid doped Polyaniline Nanofibers

M. Kuralselvi1, M. Sivanantham2

1,2 Department of Physics, Centre for Research and Development, PRIST University, Vallam, Thanjavur 613 403, Tamilnadu, India. ------***------Abstract – We report the synthesis of PANI(PANI) reported an easy route to the synthesis of PANI nanofibers nanofibers by carefully doping with different acids such us by chemical oxidative polymerization of aniline in a hydrochloric acid(HCL), acetic acid(AA) and perchloric acid surfactant gel. The prepared PANI nanofibers may be used in (PCA). The role of doping on the structure and morphological several applications such as chemical sensors or actuators, changes in PANI nanofibers were characterized by Fourier gas-separation membranes and neuron devices. Wang and transform infrared (FTIR) spectroscopy, ultra-violet-visible colleagues [14] prepared the PANI nanofibers by (UV-Vis) spectroscopy, dynamic light scattering (DLS) and polymerization of aniline using chloroaurate acid as the scanning electron microscopy (SEM) analyses. FTIR results oxidant. were utilized to reveal the functional groups present in the acid doped PANI nanofibers. DLS and SEM analyses have been Herein, we report the fabrication of PANI nanofibers employed to find out how the size and morphologies of PANI with same concentration of PANI and doping with different nanofibers vary with doping by various acid dopants. acids. In addition, we investigate the influence of these acids on the structure and morphological changes in PANI Key words: Polyaniline, nanofiber, HCL, PCA, morphology nanofibers by Fourier transform infrared (FTIR) spectroscopy, ultra-violet-visible (UV-Vis) spectroscopy, 1. INTRODUCTION dynamic light scattering (DLS) and scanning electron microscopy (SEM) experiments. Conducting polymers are fascinating category of materials since their electronic, optical and magnetic 2. EXPERIMENTAL properties are analogous to those of metals, at the same time like other polymers, they can also able to maintain the 2.1 Materials flexibility and processibility [1]. Out of number of conducting polymers, polyaniline (PANI) is comprehensively studied Different chemicals were used as follows: aniline as polymers because it can be easily synthesized, monomer, ammonium persulfate (APS) as initiator, environmentally stable and possessing interesting redox perchloric acid (PCA), hydrochloric acid (HCL) and acetic properties [2]. In addition, PANI based nanostructures have acid (AA) as doping agents. Doubly distilled water was used received great attention because of their wide range for polymer preparation. All reagents were used without technological applications as field effect devices, chemical further purification. sensors, electromagnetic shielding and anti-corrosive coatings [3-9]. 2.2 Synthesis of acid doped PANI nanofibers

Recently PANI nanostructured materials have been PANI nanofibers having same concentration (0.1 M) but prepared in the forms of nanofibers and nanotubes by doped by three different acids having same concentration of interfacial polymerization and template synthesis. Su et. al 0.1 M were synthesized. Aniline with concentration of 0.1 M [10] prepared the acid doped PANI nanofibers by interfacial was dissolved separately in the 0.1 M of HCl and 0.1 M of AA polymerization. It was found that acid doped PANI and 0.1 M of PCA. By mixing ammonium peroxydisulfate nanofibers have different thermal stability than that of (APS) separately in the 0.1 M of HCl and 0.1 M of AA and 0.1 emeraldine base PANI nanofibers. M of PCA to obtain the three different initiator solutions. Prior to polymerization, the monomer solution containing Tang and co-wrokers [11] examined the influence of aniline and initiator solution having APS were subjected to different molar ratios of aniline (AN), ammonium degassing separately by nitrogen gas for 10 and 5 min peroxydisulfate (APS) and HCl on the polymerization of AN. respectively so as to remove the dissolved oxygen. After that Zhang et. al. [12] fabricated D-10-camphorsulfonic acid (D- the polymerization has been performed by adding the CSA) doped PANI nanotubes. It was found that the diameter initiator solution drop wise into the solution having the D-CSA) doped PANI nanotubes was 80–180 nm and monomer under continuous stirring for 1 day by magnetic conductivity of 3.4 × 10-3 to 3.5 × 10-1 S cm-1. Li et. al. [13] stirrer. Light green colour was formed during the beginning

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 04 Issue: 09 | Sep -2017 www.irjet.net p-ISSN: 2395-0072 of polymerization. Later the colour was changed to dark 3.2 FTIR results green colour solution with increase in time. This colour change confirmed the formation of PANI nanofibers. Finally 100 dark green precipitates were noticed for irrespective of 90 (a) acids. Polymerizations were carried out at room 80 2854.77cm-1 741.04cm-1 70 2962.23cm-1

2925.29cm-1 800.70cm-1 temperature. Final products were purified by centrifuge 1637.81cm-1 1492.27cm-1 60 878.80cm-1 507.90cm-1 1234.58cm-1 (REMI, India) at 3500 rpm. After purification the samples 3426.51cm-1 50 3226.63cm-1

3158.74cm-1 %T 693.43cm-1 1568.92cm-1 1290.46cm-1 were utilized for characterization. 40 725.52cm-1 657.66cm-1 1442.53cm -1

1402.00cm-1 30 619.09cm-1

2.3 Characterization of acid doped PANI nanofibers 1112.43cm-1 10 0 4000 3500 3000 2500 2000 1500 1000 500 400 cm-1 Perkin-Elmer Spectrum 2 model spectrometer was Name Description MK-HCL- used to record the FTIR spectra by KBr pellet method. 100 Systronics Double Beam UV-VIS Spectrophotometer, 2202 90 (b) was employed to capture the UV-Visible spectra. Effect of 80 70 acid doping on the hydrodynamic size of PANI nanofibers 60 2854.72cm-1

50 2924.95cm-1 3402.23cm-1 were determined by Particle analyser-Nano plus. Variation %T 1638.50cm-1 741.34cm-1

3228.25cm-1 8 7 7 . 3 8 c m - 1 40 822.43cm-1 617.16cm-1 1567.13cm-1 601.57cm-1 of surface morphologies of PANI nanofibers with respect to 1490.85cm-1 694.03cm-1 1289.81cm-1 30 1401.89cm-1 1444.01cm-1 doping was monitored by Scanning electron microscope 1062.42cm-1 20

1122.48cm-1 1150.21cm-1 (Carl-Zeiss, EVO-18). 10 1176.02cm-1

0 4000 3500 3000 2500 2000 1500 1000 500 400 cm-1 Name Description 3. RESULTS AND DISCUSSION MK-AAG-

100

3.1 UV-Vis spectroscopic results 90

80 (c)

70 3751.44cm-1

50 1492.99cm-1 %T

2854.93cm-1 742.24cm-1 40 2925.48cm-1 1402.89cm-1

30 3426.15cm-1 819.47cm-1 620.85cm-1

(a) 3235.34cm-1 1569.32cm-1 1289.77cm-1 20 1443.53cm-1 1120.86cm-1 10

0 4000 3500 3000 2500 2000 1500 1000 500 400 cm-1 Name Description MK-PCA- Fig-2. FTIR spectra of various acid doped PANI nanofibers. (a)- AA , (b) - HCL and (c) - PCA.

In order to verify the formation of PANI and examine the effect of acid doping on PANI nanofibers, FTIR (b) measurements were carried out. Figure 2 represents the FTIR spectra for acid doped of PANI nanofibers. PCA treated PANI nanofibers showed poor transmission (55%) at wave number of 4000 cm-1. All acid doped PANI nanofibers have the peak at 1569 cm-1 and this is attributed to quinoid deformations of the emeraldine form of PANI nanofiber. The creation of PANI nanofibers were validated by the FTIR spectra.

In this section, we discuss how the surface morphologies of the PANI nanofibers affected by doping of different acids.

Figure 3 represents the SEM observations of three acid Fig-1: UV-Vis spectra of different acid doped PANI doped PANI nanofibers. In the case of AA doped PANI nanofibers. (a)- AA , (b) - HCL and (c) - PCA. nanofibers, fiber-like structures were seen. In contrast, fiber-

like and also bigger particles have been noticed for HCl and

PCA doped nanofibers.

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 04 Issue: 09 | Sep -2017 www.irjet.net p-ISSN: 2395-0072

(a) first distribution was around 3 nm. For the second distribution, average size of about 400 nm was seen. In contrast, in the case of PCA doped PANI nanofibers, only one (a) distribution was observed with average size of particles is 10 nm.

(a)

(b)

(c)

Fig-3. Variation of surface morphologies of PANI nanoparticles for different acid doping. (a)- AAC , (b) - HCL and (c) - PCA.

3.4 DLS results

To investigate the hydrodynamic behavior of different acid doped PANI nanofibers, DLS measurements have been conducted. Figure 4 shows the size distributions of PANI nanofibers upon doping with different acids. It was Figure 4. Effect different acid doping on the particle noticed from this figure that there are two distributions of size of PANI nanofibers. (a)- AAC , (b) - HCL and (c) - particles for the cases AA and HCl. Mean particle size for the PCA.

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 04 Issue: 09 | Sep -2017 www.irjet.net p-ISSN: 2395-0072

4. CONCLUSIONS shielding properties. The Royal Society of Chemistry 2015. PANI nanofibers were systematically doped by three different acids such as AA, HCl and PCA. We have also [9] Radhakrishnan S , Sonawane N and Siju CR . Epoxy investigated the effect of doping of PANI nanofibers with powder coatings containing PANI for enhanced different acids by UV-Visible spectroscopy, FTIR, SEM and corrosion protection. Progress in Organic Coatings 64 DLS studies. It was found acid doping significantly affect the (2009) 383–386. UV-Visible absorption peak of PANI nanofibers at wavelength of about 730 nm. Increase in order of affecting [10] Su B, Tong Y, Bai J, Lei Z, Wang K, Mu H & Dong this peak is AA>HCL>PCA. With the aid of FTIR spectroscopy, N. Acid doped PANI nanofiber synthesized the formation of PANI was verified. DLS results suggested by interfacial polymerization .Indian Journal of the nano and sub-micrometer sized particles were formed. Chemistry, 46A, 2007, 595-599. SEM observations revealed that fiber-like structures were [11] Tang, SJ. Wang, AT. Lin, SY. Huang, KY. Yang, CC. Yeh, formed after doping by AA whereas fiber-like and bigger JM and Chiu, KC. Polymerization of aniline under various particles have been seen for HCl and PCA doped nanofibers. concentrations of APS and HCl, Polymer Journal (2011) 43, 667–675 Acknowledgement [12] Zhang L and Wan M.Synthesis and characterization of Authors gratefully acknowledge Mr. Mahesh for help during self-assembled PANInanotubes doped with D-10- this work. Authors also thank Mr. Vincent for his assistance camphorsulfonic acid.Nanotechnology 13(2002),750- during characterization of the samples. 755.

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