Investigation of the effect of acid dopant on the physical properties of polyaniline prepared using microwave irradiation

Accepted Manuscript Investigation of the effect of acid dopant on the physical properties of polyaniline prepared using microwave irradiation Milutin Jevremovic, Zoran Zujovic, Dragomir Stanisavljev, Graham Bowmaker, Marija Gizdavic-Nikolaidis PII:

S1567-1739(14)00186-2

DOI:

10.1016/j.cap.2014.06.018

Reference:

CAP 3668

To appear in:

Current Applied Physics

Received Date: 2 March 2014 Revised Date:

26 May 2014

Accepted Date: 18 June 2014

Please cite this article as: M. Jevremovic, Z. Zujovic, D. Stanisavljev, G. Bowmaker, M. GizdavicNikolaidis, Investigation of the effect of acid dopant on the physical properties of polyaniline prepared using microwave irradiation, Current Applied Physics (2014), doi: 10.1016/j.cap.2014.06.018. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

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ACCEPTED MANUSCRIPT Highlighted

Investigation of the effect of acid dopant on the physical properties of polyaniline prepared using microwave

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irradiation

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Milutin Jevremovica, Zoran Zujovicb,c,d, Dragomir Stanisavljeve, Graham Bowmakerb and Marija Gizdavic-Nikolaidisb,e*

Public Company Nuclear Facilities of Serbia, 12-14 Mike Petrovica Alasa, Vinca, 11351

Belgrade, Serbia b

School of Chemical Sciences, the University of Auckland, Private Bag 92019, Auckland Mail

Centre, Auckland 1142, New Zealand

MacDiarmid Institute for Advanced Materials and Nanotechnology, Victoria University of

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c

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a

Wellington, PO Box 600, Wellington 6140, New Zealand. d

Faculty of Physical Chemistry, Studentski Trg 12-16, P.O. Box 137, 11001 Belgrade, Serbia

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e

Institute of General and Physical Chemistry, Studentski Trg 12-16, 11001 Belgrade, Serbia

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*Corresponding author: Corresponding author: Telephone: + 64 9 923 9424; Fax: +64 9 373 7422; Email: [email protected] (M. Gizdavic-Nikolaidis)

Abstract.

The microwave (MW) synthesis of polyaniline (PANI) is performed using potassium iodate (KIO3) as oxidizing agent in different concentrations of aqueous hydrochloric acid (HCl) at 8 and 93 W applied microwave power for duration of 10 minutes. The morphological and structural changes in synthesized MW PANI samples are investigated 1

ACCEPTED MANUSCRIPT using Scanning Electron Microscopy (SEM) and Fourier transform Infrared Spectroscopy (FTIR). With decreasing pH of the reaction medium the morphology of MW PANI samples changed from slab-like with a small amount of fibrils to porous products which consist of short, rod-like structures. The FTIR spectra confirm that the microwave generated materials

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structurally consist of PANI, but aniline oligomer peaks are observed in the FTIR at 725 and 686 cm-1 for MW PANI synthesized using 0.5 M aqueous HCl. The influence of acid dopant

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on the spin concentration of MW PANI synthesized at 8 and 93 W are examined.

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Keywords: Polyaniline, microwave irradiation, HCl dopant, SEM and EPR.

1. Introduction

Polyaniline (PANI) is one of the most extensively studied conducting polymers (CPs)

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due to its easy and low cost of synthesis, good environmental stability, high conductivity and unique redox properties [1, 2]. These properties have enabled PANI to be used in wide range of applications such as chemical/biological sensors [3, 4], electronic devices [5],

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cells [9].

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anticorrosive coatings [6], actuators/artificial muscles [7], rechargeable batteries [8] and solar

In a study of aniline chemical polymerization in a strong acidic media using a number

of different oxidizing agents such as ammonium persulphate (APS), potassium iodate (KIO3), potassium ferricyanide (K3[Fe(CN)6]) and hydrogen peroxide (H2O2), it was claimed that potassium iodate is the most convenient, since it gives good quality samples for a wide range of synthesis parameters [10, 11]. As synthesized emeraldine salt (ES) PANI is typically dedoped with strong base such as ammonium hydroxide (NH4OH) to yield the emeraldine base (EB) form of PANI [12]. The doping of EB-PANI prepared by classical synthesis (CS)

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ACCEPTED MANUSCRIPT with protonic acid such as hydrochloric acid (HCl) to yield the ES form is reported in detail in the literature [3, 11, 13-19]. The doped ES-PANI is paramagnetic. Kang et al. [12] investigated the spin concentration of ES-PANI doped with different concentrations of aqueous HCl solutions using Electron Paramagnetic Resonance (EPR) spectroscopy. The

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authors found that the spin concentration initially increases with the increasing dopant

concentration, reaches a maximum for 1 M HCl, and then decreases due to formation of

bipolarons at high doping level. The initial increase in the spin concentration was expected

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because of the increased possibility of reaction between the dopant HCl and imine nitrogens of PANI [12]. It is known that the polarons and the bipolarons are in equilibrium,with pairing

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of polarons at high doping levels to form bipolarons which are spinless so they cannot be detected by EPR [12, 20]. The ES-PANI prepared using CS method possesses a granular morphology.

PANI nanostructures [21-30] have attracted great attention since they combine unique

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electrical, optical and magnetic properties of organic conductors with high surface area. Zhang et al. [31] showed that an interfacial synthesis method yields PANI nanofiber morphology rather than nanoparticles obtained by an ultrasonic synthesis method under the

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same conditions. Furthermore several authors reported the successful preparation of PANI

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nanocomposites with elongated nanostructure [32], increased surface area and enhanced mechanical properties [28, 33, 34] using a facile interfacial polymerization approach. The rapid initiated copolymerization method was utilized to produce self-doped sulfonated PANI with well-defined, controllable nanomorphologies, sizes, dimensionalities, and electrical properties [35]. While various synthesis methods have been adopted for preparation of PANI nanomaterials with controllable size and morphology, the large scale up is still a major challenge [22, 23, 36, 37].

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ACCEPTED MANUSCRIPT The emergence of microwave-enhanced chemistry as an efficient, environmentally benign method of synthesis has been a significant development in recent years [38-41]. Features of microwave irradiation (MW) including solvent-free reactions, low waste, energy efficiency, high yields, short reaction times and possible use of alternative solvents, can play

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an important role in the development of green chemistry methods [42]. While polymer

technology forms one of the largest areas of application of microwave technology, and the methods and procedures used therein are among the most developed, the method has scarcely

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been applied to synthesis of conducting polymers (CPs).

Recently, Gizdavic-Nikolaidis et al. first introduced the MW method as a fast and

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convenient way of producing high quality PANI nanomaterials at ambient temperature [22, 23]. The authors [22] showed that remarkable improvements in the yield and rate of polymerization of PANI were obtained: ca. 76 % in 5 min, while the classical synthesis (CS) method took 5 h to achieve the same yield. The MW PANI fibers were relatively uniform

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(60-70 nm) but partial morphological heterogeneity of the PANI products [22] was noticeable. The spectroscopic studies showed very similar structures in both MW and CS PANI samples [22]. The MW method was applied to investigate synthesis of PANI using

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APS and KIO3 oxidants in 1.25 M HCl aqueous solution [23]. Gizdavic-Nikolaidis et al.

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found that the molecular weight of MW PANI samples depends on the applied power used to fine-tune the reaction conditions for obtaining PANI nanofibers with different molecular weight by varying the microwave power [23]. Both of the MW PANI samples synthesized by using either APS or KIO3[23] as an oxidant showed mainly fibrillar or rodlike morphologies regardless of the MW power applied during synthesis, although the high aspect ratio and morphological homogeneity were depended on the applied power and anion type. The same authors [22, 23, 43] hypothesized that a formation mechanism of MW PANI nanofibers involves homogeneous nucleation (rapid local heating and creation of hot spots) which is

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ACCEPTED MANUSCRIPT consistent with the previously used approaches of PANI polymerization using additives and mechanical agitation and their effects on the nucleation modes [44, 45]. In the present work we investigated for the first time the effect of the concentration of HCl acid on the eco-friendly MW synthesis and the physical properties of the resulting PANI

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prepared using KIO3 as an oxidizing agent and 8 and 93 W applied microwave power. Furthermore, for the first time the correlation of the anion doping levels and spin

concentration of as-synthesized MW PANI samples with varying concentration of HCl in the

2. Experimental

2.1. MW and CS PANI Syntheses.

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reaction medium are examined.

MW PANI samples were prepared by aniline oxidation with potassium iodate (KIO3,

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0.432 g). The oxidizing agent KIO3 was added to 12 mL of the different aqueous HCl acid solutions (0.5-3 M), followed by addition of 0.480 mL of aniline. Each MW synthesis was carried out for 10 min. Under same synthesis conditions CS PANI samples were prepared

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using 1-3 M aqueous HCl acid. The reaction mixture was filtered and washed thoroughly

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with distilled water and acetone. The retentates were dried in a vacuum oven at 40 °C for 16 hours.

2.2. Microwave Apparatus. MW irradiation was performed in a single mode focused Model Discover CEM reactor operating at 2.45 GHz with ability to control output power. The experimental parameters were set up as previously reported [23, 25]. An external cooling circuit maintained constant temperature of the reaction mixture and constant irradiation power. In

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ACCEPTED MANUSCRIPT order to maintain uniform temperature the sample was mixed by magnetic stirring at 400 rpm. As physical properties such as surface area and conductivity of the MW PANI do not change significantly with small changes in the applied microwave power [23], the MW PANI synthesis using the oxidizing agent KIO3 was performed at lower 8 and higher 93 W

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microwave power for reference. All experiments were done under the same conditions by keeping constant irradiation power, temperature and initial reaction mixture volume. The

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temperature was maintained at 24±1 oC in all experiments.

2.3. Elemental analysis.

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Elemental analysis was performed by the Campbell Microanalytical Laboratory at the University of Otago, Dunedin, New Zealand.

2.4. Scanning Electron Microscopy (SEM).

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SEM was carried out using a Philips XL30S Field Emission Gun with a SiLi (Lithium drifted) EDS detector with Super Ultra Thin Window. The MW PANI samples were 10 mm in diameter, mounted on aluminium studs using adhesive graphite tape and sputter coated

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using a Polaron SC7640 Sputter Coater at 5-10 mA and 1.1 kV for 5 min.

2.5. FTIR spectroscopy.

Mid-Infrared spectra of MW PANIs as KBr pellets were recorded at 2 cm-1 resolution

using a Nicolet 8700 FT-IR spectrometer. 100 scans were averaged for each sample.

2.6. Electron Paramagnetic Resonance (EPR) spectroscopy. EPR spectra of 7.9 mg MW PANI samples in quartz EPR tubes, were recorded at ambient temperature using a JEOL JES-FA 200 EPR spectrometer. The spin concentration

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ACCEPTED MANUSCRIPT was determined using hydrated copper sulphate (CuSO4) as a standard. The EPR spectra of the samples and CuSO4⋅5H2O were recorded under the same conditions. The spin concentration, Nsample (spins g-1) was calculated using the area calculated

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from the second integral of the first-derivative signals using Matlab according to:

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(Eq.1)

g-1.

3. Results and Discussion

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3.1. SEM

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where the reference substance used was CuSO4⋅5H2O, for which Nreference = 2.412 × 1021 spins

SEM micrographs of the PANI samples obtained at 8 and 93 W MW power with different concentrations of HCl are shown in Fig. 1. There are differences in morphology

Fig. 1

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obtained.

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depending on the pH value (i.e. the concentration of HCl) at which these products were

The product at higher pH obtained at 8W exhibits flat, slab-like structure covered by nanofibrils (Fig. 1A). This implies two different mechanisms for the product formation under these conditions: a) the one which favours cross linking and branching where the orthocoupling predominates and b) the one which favours elongated structures and where the para-

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ACCEPTED MANUSCRIPT coupling of aniline monomers prevails [46-49]. With an increase in the HCl concentration (Fig. 1B, C and D) the morphologies change, leading mostly to porous products which consist of short, rod-like structures [22, 23]. Further increase in the concentration of HCl leads towards more compact and less porous samples resembling the morphology of

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chemically synthesized PANI. The product obtained using 0.5 M HCl at 93 W (Fig. 1G) shows very clearly slab-like morphology with a lesser amount of fibrils compared to its

counterpart synthesized at 8 W, Fig. 1A). This suggests that higher power favours cross-

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linking and making slab-like structures [46-49]. A further increase in acidity leads to the

formation of entangled, elongated structures clearly seen in Fig.1H and at still lower pH to

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the formation of more compact and less porous structures (Fig. 1I-L). This trend is similar to that seen in micrographs from the samples obtained at 8 W (Fig. 1D, E and F). The result that the morphology depends on the acid concentration can potentially be used to adjust and optimize conditions for the formation of porous samples suitable for

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Fig. 2

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3.2. FTIR spectroscopy.

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sensors or filters.

The FTIR spectra of HCl doped PANI samples synthesized using different

concentration of aqueous HCl (0.5-3M) and microwave powers (8 and 93 W) are presented in Fig. 2. The FTIR spectra of MW HCl doped PANI synthesized under 8 and 93 W microwave powers (Fig. 2B-F and H-L respectively) showed characteristics peaks for chemically synthesized HCl doped PANI (ES form) as previously reported [22, 23], C-C stretching on quinoid band (1574 cm-1) and the benzene ring band (1481-1485 cm-1), the C=N band of

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ACCEPTED MANUSCRIPT imine group (1297-1305 cm-1), the band of depronated PANI (1137-1149 cm-1) and the outof-plane bending of the benzene ring (819 cm-1 ). No significant difference was observed in FTIR spectra with increasing HCl concentration (1-3 M) in the syntheses. Although the FTIR spectra (Fig.2 B-F and H-L respectively) are largely independent of the applied microwave

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power for HCl doped PANI samples using 1-3 M HCl concentrations, it was noticed that the largest shift in the deprotonated PANI band from the standard position at 1162 cm-1 to 1137 cm-1 for the protonated form was observed in the case of the higher microwave applied power

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of 93 W in comparision to 1149 cm-1 in a case when 8 W was used. It appears that a stronger influence of the applied microwave power is reflected in the FTIR spectra of 0.5 M HCl

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doped PANI samples (Fig.2A and G). Both samples showed oligomeric peaks in the region 800-600 cm-1 [48, 50], but the one synthesized at 8 W showed more PANI structure with weak oligomeric peaks in this region. This could be nicely correlated with the observed morphology of these samples (Fig.1A and 1F), where the sample synthesized at 8 W showed

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some nanofibrillar morphologies typical for PANI while in the case 0.5 M HCl doped PANI synthesized at 93 W the more flat structure typical for aniline oligomers prevailed. Also, sharp and strong peaks at 725 cm-1 and 686 cm-1 [48, 50] as well as strong C-C stretching of

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the benzenoid ring (1493 cm-1) typical for the oligomeric structures as previously reported

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[48] are present in 0.5 M HCl doped PANI sample at 93 W.

3.3. Elemental composition data, EPR results and correlation of spin concentration with the doping level in HCl doped PANI samples

The MW chemically synthesized HCl doped PANI samples are prepared using KIO3 as an oxidizing agent in the range of aqueous acid concentration 0.5 M-3 M HCl by applying 8 W and 93 W microwave powers. The elemental composition of the synthesized MW HCl

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ACCEPTED MANUSCRIPT doped PANI samples are presented in Table 1. The results of the detailed study of polymerization of aniline by KIO3 in aqueous HCl media reported by Armes and Aldissi [11] suggested that the iodine species I3- and I- were incorporated in the HCl doped PANI product.

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Table 1

The current results imply that the situation is complicated by the presence of at least

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two different dopants (chloride/iodide) in the product and/or by the use of microwave radiation in the synthesis. The main dopant based on elemental analysis (see Table 1) is

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chloride (Cl) and second dopant is iodine. As previously reported by Armes et al. [11, 51] based on Raman studies the iodine is present in the form of triodide (I3-). Spin concentrations for PANI samples synthesized at 8 and 93 W with concentration of aqueous HCl acid (M) are

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Fig. 3

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presented in Fig. 3.

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In Fig 4. the anion doping levels with concentration of aqueous HCl acid (M) for Cl-,

I3- and (I3- + Cl-) anions for - 8 W (Fig.4A) and 93 W (Fig.4B) microwave power are presented. The results show that the total doping levels (I3- + Cl-) are maximum at the lowest HCl concentration (0.5 M HCl) and then they initially decrease for both 8 W and 93 W applied microwave powers as the HCl concentration increases, but then they increase again with further increase in HCl concentration. This roughly reflects what we see in the spin concentration data from the EPR spectra of these products (Fig. 3). What is surprising,

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ACCEPTED MANUSCRIPT however, is that the doping levels are all considerably higher than those for the chloride doped products prepared by CS method using dedoping the PANI after synthesis and then redoping with HCl to remove all iodide anions. Also, the spin concentration for HCl doped PANIs prepared in this way varies systematically with HCl concentration, first showing an

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increase at low HCl concentrations due to an increase in the number of polarons, but then a decrease at higher concentrations due the formation of spinless bipolarons [12, 52]. To exclude any influence of the dedope/redope process used in ref. [12] on the doping level we

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synthesized 1-3 M HCl doped PANI in the absence of MW using 10 min reaction times and calculated the spin concentration vs. HCl concentration for prepared CS PANI samples

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(Supplementary data Fig.S1). This showed the expected systematic change in spin concentration with increasing HCl concentration, in contrast to the results discussed above for the MW-synthesized samples.

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3.4. Electrical conductivity

The electrical conductivities values for PANI samples obtained at 8 and 93 W MW power with different concentrations of HCl are shown in Table 2. There is a trend of only a

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small increase in conductivity with increasing concentration of aqueous HCl acid, with

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slightly higher values for 93 W applied microwave power. This is in agreement with the previously published results of Gizdavic-Nikolaidis et al. [23], which demonstrated that slightly increased conductivity was observed for 1M HCl doped PANI prepared under higher microwave power. The same authors [23] also noticed that the molecular weight increased with increased microwave power which agrees with the theoretically predicted weak dependence of electronic properties on chain length [53]. Furthermore, this is supported by previous published results [54], which showed that the octamer oligoanilines showed the same electrical conductivity as PANI. Recently, Gizdavic-Nikolaidis et al. showed for MW

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ACCEPTED MANUSCRIPT PANI synthesized using acetic acid as dopant that there is no significant difference in crystalinity of the samples synthesized at low 8 W and high 93 W microwave power [55]. The conductivity results obtained for MW PANI samples have ~1.5 times higher values relative to the samples prepared by CS synthesis under same condition (Supplement

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data Table S1) which is in agreement with previously reported results observed for 1M HCl doped PANI [23].

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Table 2

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4. Conclusions

The influence of the HCl acid dopant on the properties of MW synthesized PANIs at 8 and 93 W applied microwave powers has been investigated. Based on SEM images the MW

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PANIs synthesized using 0.5 M aqueous HCl for both applied microwave powers exhibit more flat structure characteristics for aniline oligomers which is in good correlation with the obtained FTIR spectra where peaks from aniline oligomers are observed. The increasing in

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acidity leads to the formation of elongated more compact nanostructures. At the same time the morphological characteristics of products obtained at different power levels did not

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exhibit notable differences. The FTIR spectra for MW PANI samples prepared using 1-3 M aqueous HCl are similar for each applied microwave power and all confirmed the formation of PANI. As the samples are characterized as synthesized without dedoping and re-doping with HCl to eliminate the second (iodine) dopant, the situation is more complicated. Based on a previous study it was assumed that iodine is present as I3-. The total anion doping levels have maxima at the lowest HCl concentration (0.5 M HCl) and then they initially decrease for both 8 and 93 W applied microwave powers as the HCl concentration increases, but then they increase again with further increase in HCl concentration which is in correlation for the trend 12

ACCEPTED MANUSCRIPT observed from spin concentration data from the EPR spectra. The doping levels are all considerably higher than those for the chloride doped PANIs prepared by CS method using dedoping the PANI after synthesis and then redoping with HCl to remove all iodide anions. This is in agreement with the conductivity results which are showing higher values for the

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MW synthesized PANI samples than the samples prepared by CS method.

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Acknowledgements

The authors would like to acknowledge the financial support from PBRF Fund School of

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Chemical Sciences, the University of Auckland and Ministry of Science and Environmental Protection of Serbia (Contract No. 172015).

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[53] J. Stejskal, J., A. Riede, D. Hlavataa, J. Prokes, M. Helmstedt, P. Holler, Synth. Met. 96

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[54] F. L. Lu, F. Wudl, M. Nowak, A. J. Heeger, J. Am. Chem. Soc. 108 (1986), 8311-8313. [55] M. R. Gizdavic-Nikolaidis, M. M. Jevremovic, M. C. Allison, D. R. Stanisavljev, G. A. Bowmaker, Z. D. Zujovic, Express Polym. Lett., accepted for publication.

16

ACCEPTED MANUSCRIPT Figure captions

Fig. 1. SEM micrographs of the MW synthesized PANIs at 8 W power with duration of 10 min. A) 0.5 M HCl doped PANI; B) 1M HCl doped PANI; C) 1.5 M HCl doped PANI; D)

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2M HCl doped PANI; E) 2.5 M HCl doped PANI and F) 3M HCl doped PANI. SEM micrographs of the MW synthesized PANIs at 93 W power with duration of 10 min. G) 0.5 M HCl doped PANI; H) 1M HCl doped PANI; I) 1.5 M HCl doped PANI; J) 2M HCl doped

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PANI; K) 2.5 M HCl doped PANI and L) 3M HCl doped PANI.

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Fig. 2. FTIR MW HCl doped PANI samples prepared at 8 W power with duration of 10 min. A) 0.5 M HCl doped PANI; B) 1M HCl doped PANI; C) 1.5 M HCl doped PANI; D) 2M HCl doped PANI; E) 2.5 M HCl doped PANI and F) 3M HCl doped PANI. FTIR MW HCl doped PANI samples prepared at 93 W power with duration of 10 min. G) 0.5 M HCl doped

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PANI; H) 1M HCl doped PANI; I) 1.5 M HCl doped PANI; J) 2M HCl doped PANI; K) 2.5 M HCl doped PANI and L) 3M HCl doped PANI.

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Fig. 3. Spin concentrations for PANI samples synthesized at 8 and 93 W with concentration

AC C

of aqueous HCl acid (M).

Fig. 4. Anion doping levels with concentration of aqueous HCl acid (M) for Cl-, I3- and I3- + Cl- anions for A) 8 W and B) 93 W microwave applied powers.

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ACCEPTED MANUSCRIPT Table 1. Elemental composition of the synthesized MW HCl doped PANI samples using 8 W and 93 W microwave powers.

MW

C (%) H (%) N (%) I (%)

Power (W)

Cl (%)

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Sample description

8

36.73

2.44

7.00

39.33

17.07

1 M HCl doped PANI

8

49.40

4.06

9.43

14.80

14.37

1.5 M HCl doped PANI

8

47.61

4.12

9.15

15.15

16.68

2 M HCl doped PANI

8

48.90

4.18

9.37

14.00

14.94

2.5 M HCl doped PANI

8

48.36

4.08

9.33

14.09

15.82

3 M HCl doped PANI

8

45.91

3.69

8.83

18.05

17.07

0.5 M HCl doped PANI

93

32.63

2.90

6.22

43.32

12.24

1 M HCl doped PANI

93

47.16

3.94

9.06

17.10

15.46

1.5 M HCl doped PANI

93

48.41

4.26

9.30

16.07

15.48

2.5 M HCl doped PANI

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93

52.30

4.62

10.04

7.25

14.28

93

46.66

3.84

8.97

15.83

16.54

93

48.35

4.12

9.29

14.71

16.00

AC C

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3 M HCl doped PANI

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2 M HCl doped PANI

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0.5 M HCl doped PANI

ACCEPTED MANUSCRIPT Table 2. Conductivity results of the synthesized MW HCl doped PANI samples using 8 W

MW power (W)

Conductivity (S cm-1)

0.5 M HCl doped PANI

8

2.18

1 M HCl doped PANI

8

3.30

1.5 M HCl doped PANI

8

3.54

2 M HCl doped PANI

8

3.79

2.5 M HCl doped PANI

8

3 M HCl doped PANI

8

0.5 M HCl doped PANI

93

1 M HCl doped PANI

93

1.5 M HCl doped PANI

93

2 M HCl doped PANI

93

AC C

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3 M HCl doped PANI

3.98

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4.13

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2.5 M HCl doped PANI

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Sample description

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and 93 W microwave powers.

2.59

3.61 3.84

4.03

93

4.34

93

4.51

AC C

EP

TE D

M AN U

SC

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ACCEPTED MANUSCRIPT

AC C

EP

TE D

M AN U

SC

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ACCEPTED MANUSCRIPT

AC C

EP

TE D

M AN U

SC

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ACCEPTED MANUSCRIPT

AC C

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TE D

M AN U

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ACCEPTED MANUSCRIPT

ACCEPTED MANUSCRIPT

Morphology of microwave synthesized polyanilines depends on acid concentration

•

Optimizing acid conditions for synthesis can be used for formation porous material

•

The total anion doping levels is independent on the applied microwave power

•

The doping levels depend on the nature of polyaniline synthesis

AC C

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•

ACCEPTED MANUSCRIPT

Supplementary data Investigation of the effect of acid dopant on the physical properties of

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polyaniline prepared using microwave irradiation

Milutin M. Jevremovica, Zoran D. Zujovicb,c,d, Dragomir R. Stanisavljeve, Graham A. Bowmakerb and Marija R. Gizdavic-Nikolaidisb,e*

Public Company Nuclear Facilities of Serbia, 12-14 Mike Petrovica Alasa, Vinca, 11351 Belgrade, Serbia

School of Chemical Sciences, the University of Auckland, Private Bag 92019, Auckland Mail

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b

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a

Centre, Auckland 1142, New Zealand c

MacDiarmid Institute for Advanced Materials and Nanotechnology, Victoria University of

d

Institute of General and Physical Chemistry, Studentski Trg 12-16, 11001 Belgrade, Serbia

Faculty of Physical Chemistry, Studentski Trg 12-16, P.O. Box 137, 11001 Belgrade, Serbia

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e

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Wellington, PO Box 600, Wellington 6140, New Zealand.

*Corresponding author: Corresponding author: Telephone: + 64 9 923 9424; Fax: +64 9 373

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7422; Email: [email protected] (M. Gizdavic-Nikolaidis)

Figure caption:

Fig. S1. Spin concentration as a function of concentration of HCl dopant for CS PANI prepared samples.

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M AN U

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ACCEPTED MANUSCRIPT

Fig. S1. Spin concentration as a function of concentration of HCl dopant for CS PANI

AC C

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prepared samples.

Table S1. Conductivity results of CS PANI prepared samples. Sample description

Conductivity (S cm-1)

1 M HCl doped PANI

2.57

2 M HCl doped PANI

2.77

3 M HCl doped PANI

2.86