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Recent Patents on Nanotechnology, 2016, 10, 157-164

157

Effect of Gold/Amine Nanoparticles on Polyaniline Electrochemical Sensi-tivity to Formaldehyde

Wessam Omara1 and Souad A. Elfeky2,3*

1Materials Science Department, Institute of Graduate Studies and Research, Alexandria University, Alexandria, Egypt; 2Laser Application in Metrology, Photochemistry & Agriculture, National Institute of Laser Enhanced Sciences, Cairo University, Giza, Egypt; 3Department of Chemistry, The University of Bath, Claverton Down, Bath, BA2 7AY (UK)

Abstract: Background: Nanoparticles have a promising potential in electrochemical sensitivity. Poly-aniline (PANI) received significant attention in the latest years owing to its high conductivity and ex-cellent electrochemical stability. This research aims to study the effect of gold nanoparticles capped octadecyl amine (Au/ODA) on polyaniline emeraldine salt (ES) electrochemical sensitivity to formal-dehyde (FA) using DPV technique. Furthermore, ES and Au-ODA/ES have been applied for the first time in sensing FA. Few relevant patents to the topic have been reviewed and cited in this article.

Methods: Emeraldine salt (ES) was prepared by doping the prepared emeraldine base (EB) powder with dodecylbenzene sulfonic acid (DBSA) at a ratio of 1:2 W/W. Then ES-DBSA was dissolved in chloroform solution and added to Au/ODA nanoparticles solution to obtain Au/ES-DBSA nanocomposite. FA sensors were prepared by depositing a film from ES-DBSA or Au/ES-DBSA on a working electrode and the potential was measured at FA different concentrations in Electro-chemical cell kit.

Results: FTIR and XRD confirmed the structure of ES-DBSA and Au/ES-DBSA. The obtained results reveal that the ES-DBSA nanosensor is an efficient sensor because it can recognize the low levels of FA starting from 0.06 ppm. The re-corded electrochemical oxidation current shows a linear direct relationship between the produced current and FA concen-tration in case of ES-DBSA nanoparticles while it illustrates a fluctuating signal with lower sensitivity in the case of the novel prepared nanocomposites (Au/ES-DBSA). This may be due to the gold capping agent (ODA), which in turn could inhibit the role of DBSA and decrease the conductivity of the nanocomposite.

Conclusion: Herein we described the application of ES-DBSA and Au/ES-DBSA nanocomposite for the first time as a novel, facile, and cheap method for electrochemical sensitive detection of formaldehyde. The gold capping agent ODA hinders the ES-DBSA conductivity through interaction with the DBSA sulfo group.

Keywords: Au/ES-DBSA, formaldehyde, gold nanoparticles, nanocomposites, polyaniline, potential. Received: January 01, 2016 Revised: February 17, 2016 Accepted: March 02, 2016

1. INTRODUCTION

Although food safety has considerably enhanced, im-provement is irregular and food-borne eruptions from bacte-rial infection, chemicals and toxins are similar in numerous countries. Consequently, the role of sensing technology for toxic materials is important, which is the key for the protec-tion and recognition of many issues relevant to health and safety. However, still a recognition strategy, which is fast, simple, sensitive and cost-effective for in situ research is yet to be developed [1]. FA is one of the principal gases that contribute to poor indoor air quality since it is commonly used in the manufac-turing and maintenance of goods and food with specific ra-tios [2]. FA in drinking water results from the oxidation of natural organic matter during ozonation and chlorination. *Address correspondence to this author at the Department of Chemistry, The University of Bath, Claverton Down, Bath, BA2 7AY, UK; Tel: 0044 7711827143; E-mail: [email protected]

It also goes into drinking water via draining from polya-cetal plastic stuff in which the safety covering has been dam-aged. FA’s primary commercial use is in the manufacture of urea-FA, melamine, and polyacetal resins. Its second biggest use is in the commercial synthesis of a variety of organic compounds. It is also used in beauty products, fungicides and fabrics [3]. Over time FA, even at very low levels, can cause health problems and a common feeling of un-wellness. The World Health Organization (WHO) declares that FA expo-sure should not surpass 0.08 ppm in a 30-minute period [2]. The inhaled FA gas has side effects on the central nervous system, which develop in the form of a headache, insomnia, anorexia, and dizziness. There is a correlation between in-door FA concentrations and the sickening symptoms. Long-term contact (e.g., 14-30 year) to FA may trigger permanent neurotoxicity and brain cancer (astrocytoma) [4].

The nanocomposites having organic polymers and inor-ganic particles in the nanoscale size offer absolutely new classes of materials with novel characteristics. The polyaniline

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158 Recent Patents on Nanotechnology, 2016, Vol. 10, No. 2 Omara and Elfeky

emeraldine base is the stable form of PANI and its conductivity can be improved by the inclusion of metal nanoparticles [5]. Among the organic polymers, polyaniline received signifi-cant attention in the recent years owing to its high conductiv-ity and excellent thermal, electrochemical and environmental stability.

The polyaniline synthesis reaction can be simply con-trolled to give high yields using the inexpensive monomer. The ability to use polyaniline as an immobilizing compound for biomolecules such as enzymes, proteins and DNA offers another advantage. It has been successfully immobilized on PANI modified electrodes and showed excellent perform-ance. It has proven particularly useful in the development of biosensors [6]. The sensing performance of polyaniline is highly dependent on synthesis conditions, chemical composi-tion, and morphology. A recent patent entitled “System and method for analyzing and measuring ammonia levels in a sample” invented by Killard Anthony and collaborators (2014) [7], describes a system for sensing and measuring ammonia in a breath sample using polyaniline.

The level of polyaniline electrical conductivity depends on the mechanisms employed in its production for applica-tions in chemical or biological sensing [1]. The earliest and most widely used conducting polymeric systems were com-posites in which an insulating polymer matrix was filled with particulate or fibrous conductive filler to improve their con-ductivity. However, conducting polymers such as polyaniline and polypyrrole now offer excellent mechanical and electri-cal properties [8]. Among the nanocomposites, polyaniline composites are inexpensive material systems and are easily formed by chemical or electrical reduction of metal ions fol-lowing the polymerization of aniline monomer. This particu-lar system has recently received remarkable interest due to the nanoparticle size tunability, long-term solution stability, and potential chemical uses [9]. The electrochemical, optical and electrocatalytic activities of PANI can be greatly in-creased if PANI is combined with gold nanoparticles [6]. Depending on the excellent electrochemical behaviour of PANI, in addition to the good biocompatibility of Au, one can imagine that when PANI is modified by Au, the resultant composite will have excellent properties and might be used to construct a good biosensor [10].

The aim of this work is to study the effect of gold nanoparticles capped octadecyl amine (Au/ODA) on poly-aniline (ES) electrochemical sensitivity to FA using DPV technique. Furthermore, ES and Au-ODA/ES have been ap-plied for the first time in sensing FA.

2. EXPERIMENTAL WORK

2.1. Chemicals All materials and solvents used in the present study are chemically pure grades. Aniline monomer (98%), HAuCl4 (99.999%), citrate trisodium salt (98%), ferrous chloride (98%), Dodecylbenzene sulfonic acid (DBSA), Ammonia hydroxide and formaldehyde were purchased from Sigma-Aldrich. Hydrogen peroxide 30%, Dihydrogen phosphate

and disodium hydrogen phosphate, were purchased from Oxford Laboratory Mumbai anhydrous (LOBA Chemicals).

2.2. Polyaniline Preparation Generally, 2.35 ml of aniline (0.03 M/L) was firstly sus-pended in 300 ml hydrochloric acid (1 M/L). 0.0064 g of ferrous chloride (FeCl2) was dissolved in 75 ml water, and then added to the previous aniline suspension with stirring to initiate the polymerization. During the first half hour of stir-ring, a 68 ml of the H2O2 (6 wt%) solution was added (drop wise) to the aniline and completed in a 30-minute period. After that, the mechanical stirring was continued for 23 h. All stages of polymerization were performed at room tem-perature. The product was gathered on a filter paper and rinsed until the colourless filtrate appeared. The filtered sample was doped with ammonia water (5 wt%) for 3 h and carefully washed with water until the filtrate became neutral. The polymer emeraldine base (EB) form was obtained after drying in the vacuum (50oC), and then powdered in a mortar [11].

2.3. Gold Nanoparticles Preparation

The gold nanoparticles colloidal solution was prepared by adding citrate trisodium salt (0.0882 g dissolved in 30 ml distilled water) to 150 ml boiled solution of chloroauric acid (HAuCl4) 10-3M. Red-coloured gold nanoparticles formed. The capping agent octadecyl-amine (ODA) was prepared in the chloroform by dissolving 0.0135 g ODA in 50 ml chloro-form. Then this chloroform-ODA solution was added to the gold colloidal solution. Two layers were formed, one being the colourless organic layer and the second red-coloured gold nanoparticles. Transfer of the gold colloidal particles into the organic phase was accomplished after vigorous stir-ring of the two-phase mixture for 24 h [12].

2.4. Preparation of Gold-polyaniline Nanocomposites (Au/ES-DBSA)

The nanocomposite was prepared by doping 0.05 g of EB powder with 0.1 g of dodecylbenzene sulfonic acid (DBSA) at a ratio of 1:2 W/W to obtain the conducting nanoparticles emeraldine salt (ES-DBSA) [13]. Then the resulting ES-DBSA nanoparticles (NPs) were dissolved in 10 ml chloro-form solution afterwards, 4 ml of the above solution was diluted with 10 ml of chloroform. When diluted ES-DBSA NPs solution was added to Au/ODA nanoparticles solution, the colour of the gold solution changed from wine red to dark green. It was found that optimum absorption peak for Au/ES-DBSA nanocomposite was achieved at the ratio of 4 ml (ES-DBSA): 6 ml (AuNPs).

2.5. Formaldehyde Sensor

2.5.1. Preparation of Formaldehyde Sensor Electrode

The surface of the carbon electrode was polished using 0.05µm-alumina slurry on a smooth cloth to ensure the sur-face was cleaned from any foreign residues. After that, it exposed to a highly purified nitrogen stream, submerged in ES-DBSA dissolved in 10 ml chloroform solution and left in the air to evaporate and completely drys forming the sensor

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Effect of Gold/Amine Nanoparticles on Polyaniline Electrochemical Recent Patents on Nanotechnology, 2016, Vol. 10, No. 2 159

film. Another working electrode of Au/ES-DBSA nanocom-posite was prepared using the same procedure. A platinum plate was used as a counter electrode. All potentials were measured vs. saturated calomel electrode (SCE) as a refer-ence electrode [14, 15].

2.5.2. Electrolyte Preparation (Sensing Media)

FA is miscible in water (phosphate buffer, pH=7) at the used low concentrations range (0.06-0.27 ppm) [16]. After a preliminary electrochemical study, DPV conditions were a step size of 20 mV, sample period of 5 s, a pulse time of 0.1 s, and a pulse size of 50 mV. Electrochemical measurements were done using EuroCell™ Electrochemical cell kit of Gamry instruments, USA.

3. RESULTS AND DISCUSSION

3.1. UV-Vis Spectroscopy

UV-Vis spectroscopy is a sensitive technique for study-ing the protonation and the interaction between the solvent, the dopant, and the polymer chains. Fig. 1(a) shows the opti-cal absorption spectra of the ES-DBSA. The peak at 375 nm can be attributed to the localized polarons that are the char-acteristics of the protonated polyaniline. The peak at 770 nm is assigned to an oxidized electrically conducting emeraldine salt of the polyaniline as mentioned by Samuelson et al (2003) in their patent [17] when they found similar UV-Vis absorption peak of sulfonated polyaniline. Protonation of PANI with DBSA led to a red shift in the absorption spectra than that reported by us [18] when DMSO was used as a solvent. Thus, DBSA not only serves as a solvent but also acts as a dopant by interaction with the polymer chain, resulting in the chain extension and change in molecular conformation [19].

The spectrum of Au/ES-DBSA dissolved in chloroform is shown in Fig. 1(b). Three peaks can be identified; Au NPs

plasmonic peak at 535 nm, two peaks at 375 nm and 775 nm that belong to the doped ES-DBSA [20]. The inset of Fig. 1(b) shows the UV-Vis spectrum of Au/ODA NPs where the plasmonic peak at 526 nm was clearly identified. The red shift of the Au NPs plasmonic peak inside the composite was due to the interaction between the amino group in Au cap-ping (ODA) and the sulfo group of ES-DBSA.

3.2. Fourier Transform Infrared (FTIR) Spectroscopy

The FT-IR spectra of EB, ES-DBSA and Au/ES-DBSA are shown in Fig. 2 (a, b & c) respectively. In Fig. 2(a), the two characteristic peaks at 1573 and 1510 cm-1 were as-signed to the stretching vibration of the quinoid ring and benzenoid ring, respectively [21].

The band at 1156 cm-1 was assigned to in-plane bending vibration of C-H mode of N=Q=N, Q=N+H-B and B-N+H-B which formed during protonation. The peak at 1324 cm-1 corresponded to C-N stretching of the secondary amine of PANI backbone [22]. It emerged that upon DBSA treatment (Fig. 2b), peak arises at 1645 cm-1which could be due to DBSA benzene ring. Other peaks positioned at about 2340 cm-1 and 2370 cm-1 were assigned to -CH stretching of DBSA-doped poly-aniline [23-25]. The peak at 605 cm-1 was ascribed to the S=O bond stretching of DBSA [17]. The decrease in the intensity of the quinoid band relative to the benzenoid band indicated the doping of BANI with DBSA [18]. The FTIR observations clearly indicate the for-mation of ES-DBSA nanoparticles [26]. Fig. 2(c) shows that the small two peaks at 2920 and 2850 cm-1 are due to ODA C-H of (CH2) and C-H of (CH3) stretching frequencies, respectively [27]. These results suggest that C–N bonds in the polymer are directly influenced by the Au NPs, which are consistent with the donation of electron density from the metal to the C–N

Fig. (1). UV-Vis spectra of (a) ES-DBSA and (b) Au/ES-DBSA nanocomposites, the inset is the plasmonic peak of Au/ODA NPs.

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bond that is strongly perturbed by the presence of the Au NPs [28-30]. The interactions between the ES-DBSA and Au-ODA NPs, suggested that the formed material is a com-plex. Thus, the FTIR spectra distinctly shows that metallic gold is definitely incorporated into the polymer matrix and the most probable site of interaction could be the amine and imine nitrogen sites of benzenoid and quinoid moieties, re-spectively.

3.3. Electron Microscope (SEM, TEM)

SEM and TEM investigated the morphology and size of the prepared materials, EB, ES-DBSA, Au NPs and the Au/ES-DBSA nanocomposite. Fig. (3a, b) shows the SEM of the EB with images taken at different zooming. The image of EB shows the growth of flower-like structures with diameters around 2.5-4 µm, (Fig. 3a). Zooming into the formed flowers, (Fig. 3b) we can

identify a hierarchical flower-like structure. The aggregation of the nanoparticles into microspheres forms a kernel for the flower. The coordination of microspheres with the nanopar-ticles eventually constructs the flower-like structure. Adding the dopant, DBSA, and preparing films resulted in a total change in the morphology; the surface appears homogenous with some cracks, which formed during the solvent evapora-tion (Fig. 3c). The inset of the Fig. 3(c) shows a cross-sectional image from which the thickness of the film is cal-culated and found to be 0.7µm. The TEM of the Au NPs capped with ODA is shown in Fig. 4(a). It shows the formation of well-dispersed Au nano-spheres with size ranging from 10 to 20 nm. The capping agent, ODA, helps in getting well-dispersed nanoparticles and preventing aggregation later on. This, in turn, enhances the nanoparticles stability with time. The SEM image in Fig. 4(b) indicates the homogeneous distribution of Au within ES-DBSA, where the spherical gold nanoparticles appear as

Fig. (2). FTIR Spectroscopy of (a) Emeraldine Base [EB], (b) Emeraldine Salt [ES-DBSA] and (c) Au/ES-DBSA nanocomposites.

Fig. (3). SEM images of (a) the EB nanopolymer, (b) high magnification to one of the EB flower-like structures and (c) ES-DBSA thin film, the inset is a cross-sectional SEM image of the ES-DBSA thin film.

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light spots on the surface of the polymer film with a size range from 0.012-0.027µm. Au/ES-DBSA TEM image (Fig. 4c) illustrates the shape and distribution of both Au and ES-DBSA in a liquid sample. 3.4. XRD

X-ray diffraction (XRD) is used to compare the crystal structure of EB, ES-DBSA and Au/ES-DBSA nanocompo-sites. Fig. 5(a) shows that the typical pattern of EB powder synthesized by us using chemical methods [18]. Also from Fig. 5(b), one can identify two broad peaks at approximately 2θ =8◦ and 2θ = 20◦ signifying the amorphous nature of the prepared PANI after DBSA doping. The peak at 2θ = 20◦ is the characteristic peak of PANI. Meanwhile, the lowest an-gle peak at 2θ =8◦ could be related to the intervention of the doping ions [21]. In many reports, doped PANI shows a peak at 2θ = 25◦ which is not shown in our case due to the strong amorphous nature of the prepared PANI. This may be due to the inter-chain bonding, which is mainly responsible for ag-gregate formation [31]. The new peaks of PANI/Au nanocomposite (Fig. 5c) that are at 2 θ values of 32.8◦, and 53.7◦, corresponding to Bragg’s reflection from the (1 1 1) and (2 0 0) planes of Au respectively. These new peaks are in good agreement with

previously reported data (JCPDS-ICCD, 870720) and sup-port the existence of AuNPs in the ES-DBSA forming nano-composite (Au/ESDBSA) [32].

3.5. DIFFERENTIAL PULSE VOLTAMMETRY (DPV)

The polyaniline electrochemistry was patented before by MacDiarmid and Somasiri (1991) and MacDiarmid (1990) who found that polyaniline improved the electrochemical sensitivity of the prepared electrodes [33, 34]. In this study, DPV technique was used to measure the sensitivity of ES-DBSA and Au/ES-DBSA nanocomposites to FA. The DPV of ES-DBSA electrode prepared in phosphate buffer of pH 7 at different FA concentrations is shown in Fig. 6(a, b). There is one peak at 29.72 mV (Fig. 6a); this peak corresponds to the redox process of the oxidized form of ES. The change in the intensity of this peak after adding the FA could be due to the interaction between the imine group of ES-DBSA and the carbonyl group of FA. Furthermore, the sulfonated polyani-line salt has a rapid electronic response to electrochemical potentials as described in a patent by Epstein and Yue (1991) [35]. In addition, a US patent by Rogers Robin (2014) [36] clarified that the introduction of a sulfo group into polyani-line, improved the coulombic interactions between the phases.

Fig. (4). Electron Microscopy (a) TEM Image of Au/ODA nanoparticles, (b) and (c) SEM and TEM images of the Au/ES-DBSA nanocom-posite respectively.

Fig. (5). XRD of the prepared nanomaterials, (a) Emeraldine Base [EB], (b) Emeraldine Salt [ES-DBSA] and (c) Au/ES-DBSA nanocomposites.

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Fig. (6). Nano ES-DBSA Electrochemical sensor for FA (a) DPV curve, sample period: 5 s, pulse time: 0.1 s, and pulse size: 50 mV and (b) change of current (mA) as a function of FA concentration.

Fig. (7). Au/ES-DBSA nanocomposite electrochemical sensor for FA (a) DPV curve, sample period: 5 s, pulse time: 0.1 s, and pulse size: 50 mV and (b) change of current (mA) as a function of FA concentration. The recorded electrochemical oxidation current shows a linear change in the current from 8.327 mA to 9.89 mA with the increase of the FA concentration from 0.06 to 0.27 ppm (Fig. 6b). Fig. (7a) shows the DPV of Au/ES-DBSA working elec-trode. One can clearly see the non-monotonic behavior of current at different FA concentrations range. The current fluctuates between values of 9 mA to 3 mA Fig. 7(b). The lack of sensitivity, in this case, could be attributed to the low conductivity value of the prepared composite. The introduc-tion of Au NPs is supposed to further enhance the conductiv-ity of the ES-DBSA. This unexpected behaviour could be understood in relation to the ODA capping agent. The highly positive charged amino group NH2 is the active head of the ODA compound and is free to interact with the highly nega-tive sulfo group, SO3- of the DBSA dopant. This, in turn, could inhibit the dopant role in enhancing conductivity and give a ride to the non-monotonic observed behavior.

In order to confirm the obtained DPV results, conductiv-ity and current of ES-DBSA and Au-ODA/ ES-DBSA were measured. The values of the redox peaks in Fig. 8(a) differed when the ES-DBSA working electrode was replaced by Au/ES-DBSA electrode. The conductivity value of the ES/DBSA was found to be 2.7×10-7 S.cm. The conductivity of the Au/ES-DBSA nanocomposite was less than that of ES-DBSA by approximately one order of magnitude (4.3×10-8 S.cm). The conduction mechanism for ES-DBSA film can be explained by considering that the doping process creates defects (polarons) inside the polyaniline backbone and acts as acceptor (p-type) semiconductor film [37]. Thus, the doping process of the conducting polymer introduces charge carriers, in the form of charged polarons (i.e., radical ions) or bipolarons (i.e., dications or dianions). The ordered movement of these charge carriers along the conjugated con-ducting polymer and backbone produces high electrical con-ductivity.

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The unexpected decrease in the electrical conductivity when Au/ODA NPs are introduced to the system could be understood as follows; the long chain of the capping agent ODA compound gives rise to the insulating characteristics that act as a barrier to the interfacial electron transfer. This result is reflected in the performance of the prepared sensor when using the composite Au/ES-DBSA.

Differential pulse voltammetry performed for the two materials (Fig. 8b) showed the lower current value of Au/ES-DBSA (II) than that obtained from ES-DBSA (I). This, in turn, could be understood because of the lower con-ductivity of the Au/ES-DBSA nanocomposite as explained before.

4. CONCLUSION

FA sensor based on polyaniline and polyaniline/Au nanocomposite, are successfully synthesized. Electrochemi-cal-based FA sensor shows a linear correlation between the FA different concentrations and the measured current in the case of ES-DBSA working electrode with a good FA sensi-tivity. In the case of Au/ES-DBSA nanocomposite, no defi-nite behavior is observed due to the ODA capping agent, which in turn could inhibit the role of dopant and decrease the conductivity of the nanocomposite.

5. CURRENT & FUTURE DEVELOPMENTS

In this paper, we introduced an electrode nanosensor synthesized from nano ES-DBSA. Using this nanoscale ES-PANI offers the possibility to increase the performance of the electrode sensor due to the large surface area existing in nanostructured compounds. The introduction of gold nanoparticles capped with ODA hinders the ES-DBSA con-ductivity through the interaction of ODA with the DBSA sulfo group. Future developments will include studying the effect of different capping agents and different shapes of gold

nanoparticles on the electrochemical sensitivity of polyani-line to FA en route for achieving superior FA electrochemi-cal sensor. Development of such electrode nanosensor will have a high impact on the detection of low concentrations of FA that could affect the environment and the global health. Therefore faster response and increased sensitivity can be obtained using such sensors.

CONFLICT OF INTEREST

The authors whose names listed in this manuscript certify that they have NO affiliations with or any involvement with any organization of any financial interest or non-financial interest in the subject matter or materials discussed in this manuscript.

ACKNOWLEDGEMENTS

This work was sponsored by National Institute of Laser Enhanced Science, Cairo University, Egypt and Institute of Graduate Studies and Research, Alexandria University, Egypt.

REFERENCES [1] Arshak K, Velusamy V, Korostynska O, Oliwa-Stasiak K, Adley

C. Conducting polymers and their Applications to biosensors: Emphasizing on foodborne pathogen detection. IEEE Sensors J 2009; 9(12): 1942-51.

[2] Elizabeth-Stewart MK. Doped Polyaniline for Gas Sensors for the Detection of Formaldehyde. M. Sc. Thesis, the University of Wa-terloo, Ontario, Canada, 2011.

[3] WHO information products on water, sanitation, hygiene and health. Available at: http://www.who.int/water_sanitation_health/ (Accessed on: May 23, 2015).

[4] Songur A, Ozen OA, Sarsilmaz M. The toxic effects of formaldehyde on the nervous system. Rev Environ Contam T 2010; 203:105-18.

[5] Afzal BA, Akhtar JM. Investigation of ageing effects on the electrical properties of polyaniline/gold nanocomposites. Nucleus 2011; 48 (1): 17-21.

[6] Tamer U, Seçkin İA, Temur E, Torul H. Fabrication of biosensor based on polyaniline/gold nanorod composite. Int J Electrochem 2011; 1-7.

Fig. (8). (a) Cyclic voltammograms of ES-DBSA (I) and Au/ ES-DBSA (II) in the buffer at pH 7 and (b) DPV of ES-DBSA (I) and Au/ ES-DBSA (II) in the buffer at pH 7, sample period: 5 s, pulse time: 0.1 s, and pulse size: 50 mV.

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-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0-0.006

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[7] Killard A, Troy H, Karl C. System and method for analysing and measuring ammonia levels in a sample. WO2014056961A1, 2014.

[8] Kazimi R M. Characterization of functionalized low density polyethylene/polyaniline nano fiber composite. J Med Bioeng 2014; 4: 306-10.

[9] Tseng JR, Baker OC, Shedd B, et al. Charge transfer effect in the polyaniline-gold nanoparticle memory system. Appl Phys Lett 2007; 90 (5): 053101-3.

[10] Feng X, Mao C, Yang G, Hou W, Zhu J. Polyaniline/Au composite hollow spheres : Synthesis, characterization, and application to the detection of dopamine. Langmuir 2006; 22(9): 4384-9.

[11] Wang Y, Jing X, Kong J. Polyaniline nanofibers prepared with hydrogen peroxide as oxidant. Synt Met 2007; 157: 269-75.

[12] Swami A, Jadhav A, Kumar A. Water-dispersible nanoparticles via interdigitation of sodium dodecylsulfate molecules in octadecylamine-capped gold nanoparticles at a liquid-liquid interface. J Chem Sci 2003; 115(5): 679-87.

[13] Pan W, Zhang Q, Chen Y. Characterization of PAN/PANI-DBSA blend nanofibers produced by electrospinning method. Optoelect Adv Mat 2010; 4 (12): 2118-22.

[14] Ling YP, Heng LY. A potentiometric formaldehyde biosensor based on immobilization of alcohol oxidase on acryloxysuc-cinimide-modified acrylic microspheres. Sensors 2010; 10: 9963-81.

[15] Schuhmann W. Amperometric enzyme biosensors based on opti-mised electron-transfer pathways and non-manual immobilisation procedures. J Biotechnol 2002; 82: 425-41.

[16] Marzuki IN, Bakar AF, Salleh BA, Heng YL, Yusof AN. Development of electrochemical biosensor for formaldehyde determination based on immobilized enzyme. Int J Electrochem Sci 2012; 7: 6070-83.

[17] Samuelson LA, Tripathy SK, Bruno F, Nagarajan R, Kumar J, Liu W. Enzymatic polymerization of anilines or phenols around a tem-plate. US6569651B1, 2003.

[18] Wessam O, Rehab A, Hanan E, Medhat I, Souad AE. Preparation and characterization of novel polyaniline nanosensor for sensitive detection of formaldehyde. RPNANOTEC 2015; 9: 195-203.

[19] Milind VK, Annamraju KV, Khanna KP. Synthesis and characteri-zation of Poly(N-Methyl Aniline) doped with sulfonic acids: Their application as humidity sensors. J Appl Polym Sci 2006; 99: 812-20.

[20] Xian Y, Hu Y, Liu F, Xian Y, Wang H, Jin L. Glucose biosensor based on Au nanoparticles-conductive polyaniline nanocomposite. Biosens Bioelectron 2006; 21(10): 1996-2000.

[21] Han D, Chu Y, Yang L, Liu Y, Lv Z. Reversed micelle polymerization: a new route for the synthesis of DBSA–polyaniline nanoparticles. Coll Surf A 2005; 259: 179-87.

[22] Babazadeh M. Aqueous dispersions of DBSA-doped polyaniline: One-pot preparation, characterization, and properties study. Appl Polym Sci 2009; 113: 3980-4.

[23] Rizzo G, Arena A, Donato N, et al. Flexible, all-organic ammonia sensor based on dodecylbenzene sulfonic acid-doped polyaniline films. Thin Solid Films 2010; 518(23): 7133-37.

[24] Mendes CL, Falco PA, Pinho SM, Marques OP. Sulfonated polyaniline: Influence of sulfonation routes on its thermal and structural characteristics. Mat Res 2011; 14(4) 466-71.

[25] Trchová M, Stejskal J. Polyaniline: The infrared spectroscopy of conducting polymer nanotubes (IUPAC Technical Report). Pur Appl Chem 2011; 83(10): 1803-17.

[26] Han GM, Cho KS, Oh GS, Im SS. Preparation and characterization of polyaniline nanoparticles synthesized from DBSA micellar solution. Synt Met 2002; 126(1): 53-60.

[27] Zimple M, Pratibha P, Pandey KM, Vinay G, Malhotra DB. Func-tionalized gold nanoparticles–octadecylamine hybrid Langmuir-Blodgett film for enzyme sensor. Electroanalysis 2009; 21(14): 1587-96.

[28] Kinyanjui MJ, Hanks J, Hatchett WD, Smith A, Josowicz M. Chemical and electrochemical synthesis of polyaniline/ gold com-posites. J Electrochem Soc 2004; 151(12): D113-20.

[29] Kinyanjui MJ, Hatchett WD, Smith AJ, Josowicz M. Chemical synthesis of a polyaniline/gold composite using tetrachloroaurate. Chem Mater 2004; 16(17): 3390-8.

[30] Sridevi V, Malathi S, Devi CS. Synthesis and characterization of polyaniline/gold nanocomposites. Chem Sci J 2011; 1-6.

[31] Xu Q, Leng J, Hong-bo L, Gui-ju L, Wanga Y, Xiao-Ya H. The preparation of polyaniline/gold nanocomposites by self-assembly and their electrochemical applications. React Funct Polym 2010; 70: 663-8.

[32] Matyeeva SE. Could the acid doping of polyaniline represents the charge transfer interaction? Synt Met 1996; 83: 89-96.

[33] MacDiarmid AG, Somasiri LN. Electrochemistry employing poly-aniline. US5023149A, 1991.

[34] MacDiarmid AG. High capacity polyaniline electrodes. US4940640A, 1990.

[35] Epstein JA, Yue J. Sulfonated polyaniline salt compositions, proc-esses and uses. WO1991006887A1, 1991.

[36] Rogers RD, Daly DT, Swatloski RP, Hough WL, Davis JH, Smiglak M, Pernak J, Spear SK. Multi-functional ionic liquid compositions for overcoming polymorphism and imparting improved properties for active ingredients. US8802596B2, 2014.

[37] Shi-Jian S, Noriyuki K. Dodecylbenzenesulfonic acid: A surfactant and dopant for the synthesis of processable polyaniline and its copolymers. Synt Met 2000; 108: 121-6.

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Effect of Gold/Amine Nanoparticles on Polyaniline Electrochemical Sensitivityto FormaldehydeAbstract:Keywords:INTRODUCTIONEXPERIMENTAL WORKRESULTS AND DISCUSSIONFig. (1).Fig. (2).Fig. (3).Fig. (4).Fig. (5).Fig. (6).Fig. (7).Fig. (8).CONCLUSIONCURRENT & FUTURE DEVELOPMENTSCONFLICT OF INTERESTACKNOWLEDGEMENTSREFERENCES

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