Accepted Manuscript Title: Conductive polypyrrole/viscose fiber composites Author: Wang Ning Li Guodong Yu Zhuo Zhang Xingxiang Qi Xiaoling PII: DOI: Reference:
S0144-8617(15)00289-1 http://dx.doi.org/doi:10.1016/j.carbpol.2015.03.076 CARP 9818
To appear in: Received date: Revised date: Accepted date:
20-11-2014 10-3-2015 11-3-2015
Please cite this article as: Ning, W., Guodong, L., Zhuo, Y., Xingxiang, Z., and Xiaoling, Q.,Conductive polypyrrole/viscose fiber composites, Carbohydrate Polymers (2015), http://dx.doi.org/10.1016/j.carbpol.2015.03.076 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.
Conductive polypyrrole/viscose fiber composites
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Wang Ning1*, Li Guodong1, Yu Zhuo, Zhang Xingxiang1 and Qi Xiaoling2
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1 Tianjin Municipal Key Lab of Fiber Modiication and Functional Fiber, School of Material
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Science and Engineering, Tianjin Polytechnic University, Tianjin 300389, China
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2 Aviation Key Laboratory of Science and Technology on aeronautical Life-support,
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Aerospace Life-Support Industries, Xiangyang, 441003, China
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* Corresponding author. Tel: +86 22 83955816, E-mail: [email protected]
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ABSTRACT:
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Polypyrrole (PPy) was polymerized with pyrrole (Py) as the monomer, FeCl3 as an oxidant
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and sodium dodecyl benzene sulfonate (SDBS) as the dopant on the surface of viscose fiber
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(VCF) to prepare the conductive PPy/VCF composites. Fourier transform infrared spectra
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(FT-IR), Thermal gravimetric analysis (TGA) and X-ray photoelectron spectroscope (XPS)
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proved that the interaction between PPy and VCF formed in the PPy/VCF composites. Three
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structures of N atoms (imine, amine and cationic atoms) were found in PPy of PPy/VCF
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composites. The influence of reaction conditions including reaction time, Py concentration,
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FeCl3 concentration and SDBS concentration on the morphology and the conductivity of
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PPy/VCF composites was investigated in detail. The orthogonal experiments were designed to
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determine the optimal reaction conditions: reaction time 5h, Py concentration 0.1 mol/L and
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FeCl3 concentration 0.25 mol/L. When PPy/VCF composite was washed 50 times in water,
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the conductivity still kept at 1.5 S/cm, and this value was stable for more washing.
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KEYWORDS: conductive; composites; polypyrrole; viscose fiber.
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1. Introduction
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Conductive polymers such as polyaniline (PANI), polypyrrole (PPy), and their derivatives
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have been applied on sensors (Yoon et al., 2009), fuel cell (Li et al., 2012), energy storage
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materials (Wang, Zheng, Yue, Too, & Wallace, 2011), anticorrosive material (Pruna & Pilan,
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2012) and materials for water treatment (Chandra & Kim, 2011) due to the facile synthesis
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and flexibility in processing (Liu, Liu, Poyraz, & Zhang, 2011). However, the low solubility,
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poor mechanical properties and the fabrication difficulty limited the application of these
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conductive polymers.
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Now a new attempt is to introduce conductive polymers on the biomacromolecule templates.
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Starch films were exposed to pyrrole (Py) vapors to promote polymerization of PPy on starch
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films (Vasques, Domenech, Barreto, & Soldi, 2010). The composites based on natural
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cellulosic fibers and conductive polymers was prepared using unbleached bagasse and/or rice
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straw fibers (as cellulosic raw materials) and PANI as conducting polymer (Youssef, El
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Samahy , & Abdel Rehim, 2012). PANI was incorporated into sheets of paper in order to
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obtain the composites with both the universal properties of paper product and the chemical and electrically conducting properties of PANI (Youssef, Elsamahy, & Kamel, 2012). PPy/lignosulfonate coated cotton fabrics were prepared via in situ oxidation polymerization of Py in the presence of lignosulfonate as both template and dopant (Zhu et al., 2014).
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PPy/sodium alginate nanospheres were synthesized by oxidative polymerization of Py using
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sodium alginate as the structural template (Ma et al., 2013). A PANI-gold nanocomposite is
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chemically synthesized and impregnated in chitosan matrix to immobilize cholesterol oxidase
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on an indium tin oxide-coated glass plate, which is used for the development of cholesterol 3
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biosensors (Srivastava, Srivastava, Nirala, & Prakash, 2014).
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dopant and the template to prepare PPy/alginate composites (Basavaraja, Jo, Kim, Kim, &
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Huh, 2010). And PPy nanowires were formed on a DNA template self-assemble into rope-like
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structures (Pruneanu et al., 2008). Among these templates, cellulose was specially focused on
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due to the remarkable physical properties, such as a high elastic modulus, a low thermal
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expansivity, its sustainability and low cost (Shi et al., 2014).
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Viscose fiber (VCF) is a linear β-1, 4-glycosidically linked polyglucan, which has been
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man-made in the wetting spinning with chemical stability, biocompatibility and
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biodegradation (Gurjanova, Ibragimova, Gnezdilov, & Gorshkova, 2007). As a regenerated
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cellulose fiber, VCF sources from cotton linter or other cellulose sources of wood or bamboo
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with low cost and good quality (Ramamoorthy, Di, Adekunle, & Skrifvars, 2012). VCF can be
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used as a carrier for trypsin immobilization to make the enzyme more stable, less
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immunogenic and toxigenic, and prolong the circulation time in vivo (Nikolic et al., 2014).
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The silver nanoparticles (AgNPs) imparted a yellowish color to VCFs by the incorporation of
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Alginate was also used as the
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AgNPs into the VCF matrix without the reducing or stabilizing agents. VCF itself acted as a reducer for Ag+ and then stabilized the produced AgNPs (Emam, Mowafi, Mashaly, & Rehan, 2014). VCF was a good support for enzyme and nanoparticles. In this work, Py monomers were adsorbed on VCF surface, and PPy polymers were prepared via in situ oxidation
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polymerization of Py in the presence of FeCl3 as oxidant and sodium dodecyl benzene
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sulfonate (SDBS) as the dopant. The adhesion of PPy and VCF was investigated. The effect
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of reaction conditions on the morphology and the conductivity of PPy/VCF composites were
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also studied in detail. The orthogonal experiments were designed to determine the optimal 4
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reaction conditions. PPy/VCF composites exhibited the excellent conductivity and stability.
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After washing 50 times in water, the conductivity still kept at 1.5 S/cm.
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2. Experimental
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2.1 Materials
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Py monomer was purchased from Sigma-Aldrich. VCF was provided by Tian Jin Yuanli
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Chemical Co., China. All solutions were prepared in deionized water. The other reagents were
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in analytical grade.
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2.2 Preparation of PPy/VCF composites
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VCF was soaked in acetone solution, sonicated for 30min, washed with water, and then dried
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at 60 oC for 12 h in vacuum. 0.5g VCF was added into the SDBS solution. Py was distilled
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under reduced pressure, added into the SDBS solution, and then stirred for 1 h. FeCl3 solution
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was added dropwise into the above system. The reaction proceeded at 25 oC. The reaction
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products were filtrated and washed successively with acetone and deionized water until the
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filtrate become colorless, and then dried at 40 oC for 24 h in vacuum to obtain PPy/VCF
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composites.
2.3 Characterization
Fourier transform infrared spectra (FT-IR) were recorded with resolution of 4 cm-1 in the method of attenuated total reflection by using a Thermo Nicolet Nexus. Thermal gravimetric
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(TG) curves were obtained in Universal V3.8 B equipment from TA-Instruments. VCF, PPy
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and PPy/VCF composite were heated in open alumina pans from 30 to 800℃, under a
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nitrogen atmosphere, at a heating rate of 15℃/min. X-ray photoelectron spectroscope (XPS)
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measurements were performed by using K-alpha, ThermoFisher, equipped with an Al Ká 5
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radiation source (1486.6 eV). The XPS spectra data was accomplished with the software
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XPSPEAK4.1. The morphologies of the composites were characterized using a Hitachi
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S-4800 scanning electron microscope (SEM). They were mounted on aluminium specimen
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stubs with double-sided adhesive tape and sputter coated with a 20 nm thick gold layer in
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rarefied argon, using an Emitech K 550 Sputter Coater, with a current of 20 mA for 180s. In
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the conductivity testing, the samples were pressed into pellet under 26 MPa for 15 minutes.
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The conductivity was measured at room temperature by a programmable DC voltage/ current
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detector (four-probe method). Each data shown here is the mean value of the measurement
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from at least three samples.
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water by a magnetic stirrer at room temperature for 1 h, and dried at 50 oC. This process was
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repeated for several times for conductivity testing.
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3. Results and discussion
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In the testing of washing resistance, the composite was stirred in
3.1 Characterization of PPy/VCF composites
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The FTIR spectra of VCF, PPy and PPy/VCF composite were shown in Fig. 1. For VCF, the
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strong band at 3451 and 2917 cm-1 originated from the stretching of hydroxyl groups and the C-H stretching of CH2, respectively. A strong band at 1067 cm-1 corresponded to the C-O-C pyranose ring skeletal vibration (Hu, Liu, Chen, & Wang, 2011). For PPy polymer, the broad band at 3421 cm−1 was associated with the N-H stretching vibration. The peak at 1544 cm−1 was attributed to C-N asymmetric and ring stretching. The broadband at 1303, 1167, 1037 and
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899 cm−1 were respectively ascribed to the C-H in-plane deformation vibrations, C-N
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stretching vibrations, N-H in-plane deformation vibrations, and C-H out-of-plane vibration
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(Chen et al., 2014). Compared to FTIR spectra of VCF and PPy, the characteristic peaks
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appeared in the spectra of PPy/VCF composites such as 3437, 2921 and 1544 cm−1, indicating 6
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that PPy chains integrated with VCF to form PPy/VCF composites. The bands of VCF and
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PPy at 900-1200 cm−1 could be overlapped in PPy/VCF composites. And the absorption peak
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at 3451 cm-1 in VCF, ascribed to the NH stretching vibration of PPy (Ramesan, 2013), shifted
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blue to 3437 cm-1 in PPy/VCF composite. It revealed that the interaction formed due to the
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intermolecular hydrogen bands between VCF and PPy.
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As shown in Fig. 2, TGA and derivative thermogravimetry (DTG) had been performed for
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VCF, PPy and PPy/VCF composite. The weight loss was due to the volatilization of the water,
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and the degradation of products had been monitored as a function of temperature. DTG curves
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associated with Tmax values at about 350 oC for VCF, which was ascribed to the destruction of
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VCF into a monomer of D-glucopyranose, while the mass loss of pure PPy was only about
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40% in the range of thermal degradation. For PPy/VCF composite, the obvious mass loss
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might be ascribed to the destruction of main chains of both PPy and VCF. In views of much
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lower mass loss of the composite than VCF, PPy could play a certain protective effect on the
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thermal decomposition of VCF in PPy/VCF composite duo to the coverage of PPy on VCF
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and the good interaction between PPy and VCF. Fig.3 showed the C1s, O1s, N1s, Cl2p core-level spectra and the relative binding energy (BE) for VCF and PPy/VCF composite, respectively. The chemical compositions of VCF and PPy/VCF composite were also listed in Tab. 1. The carbon content of PPy/VCF composites
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was 8.2% higher than that of VCF, indicating that VCF was covered with PPy. At the same
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time, the BE of C1s, O1s for PPy/VCF composite was lower than that of VCF. It implied the
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interaction between VCF and PPy existed. The previous study (Ding, Qian, Yu, & An, 2010)
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suggested that the bond between PPy and VCF existed in the form of hydrogen bonding. As 7
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shown in Fig. 3(c) the N1s of the composite could be deconvoluted by assigning BE of 399.8,
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400.3 and 402.1 eV for imine (-N=), amine (-NH-) and cationic atoms (N+) to illustrate three
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structures of PPy in PPy/VCF composite. This has also been widely observed in other PPy
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complexes prepared chemically or electrochemically (Kang, Neoh, Ong, Tan, & Tan, 1991;
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Castillo-Ortega, Inoue, & Inoue, 1989). In Fig. 3(d) the Cl2p core-level spectra of PPy/VCF
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composite was resolved with three spin-orbit split doublets (Cl2p3/2 and C12p1/2), with
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the BE for the Cl2p3/2 peaks lying at about 197.1, 198.6, and 200.1 eV. This readily
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indicated that the chlorine incorporated exists in three distinct chemical states (Kang ,
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Neoh, Ong, Tan, & Tan, 1991). Ferric chloride was used as both oxidizing agent and the
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dopant to improve the conductivity of PPy. The data listed in Tab.1 suggest that the Cl/N
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ratios (38.8%) in particular, were consistent with previous report (Machida, Miyata, &
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Techagumpuch, 1989). Howerer, the amount of chlorine incorporated could also vary
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somewhat with the extent and method of process, although the general line shape of the C12p
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core-level spectrum remain unchanged.
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3.2 The effect of reaction condition on the morphology of PPy/VCF composites The effect of Py concentration on the morphology of PPy/VCF composites was shown in Fig. 4. At the low Py concentration, the continuous PPy layer grew in the longitudinal grooves of VCF surface, as marked in Fig. 4(a) and (b). The low Py concentration was not enough to
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form the long PPy chains, which could not form the enough interaction with VCF, so PPy
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coated on longitudinal grooves rather than flat surface of VCF. With the increasing of Py
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concentration, the longer and more PPy chains could form the good adhesion, which made
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PPy cover both the longitudinal grooves and the flat surface of VCF, as exhibited in Fig. 4(c) 8
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and (d).
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The effect of FeCl3 concentration on the morphology of PPy/VCF composites was illustrated
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in Fig. 5. At the low concentration of FeCl3, PPy particles were dispersed on the surface of
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VCF. At the higher concentration of FeCl3, PPy layers continuously formed on the surface of
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VCF. Because Fe3+could form the complex with Py monomer, FeCl3 could increase the PPy
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chains with conjugated structure and the size of PPy. Therefore, the continuous PPy layer
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compactly covered on VCF at the high FeCl3 concentration.
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The effect of SDBS concentration on the morphology of PPy/VCF composites was shown in
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Fig. 6. The large PPy granules were poorly dispersed on VCF surface without the addition of
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SDBS. With the introduction of SDBS, the PPy granules became smaller and the distribution
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was better on VCF. However, PPy components obviously decreased on VCF surface when
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SDBS concentration reached to 0.05 mol/L. Here SDBS was used as not only the doping
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agent but also the surface active agent. The value of critical micelle concentration of SDBS in
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water is 1.2 × 10-3 mol/L, lower than the initial SDBS concentration (0.01 mol/L). In the
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processing of the composites, SDBS formed a large number of micelles, which adsorbed Py monomer, and became the templates for PPy polymerization. PPy polymerization occurred in the micelles instead of on the surface of VCF surface, so the adhesion of between VCF and PPy polymer became poor. PPy polymer easily fallen off from VCF surface, and PPy
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components obviously decreased at the high SDBS concentration.
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3.3 The effect of reaction condition on the conductivity of PPy/VCF composites
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The effect of reaction time on the conductivity of PPy/VCF composites was studied at the
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conditions of Py concentration 0.15 mol/L, FeCl3 concentration 0.25 mol/L and SDBS 9
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concentration 0.03 mol/L (in Fig.7 a). When the reaction time was 5 h, the conductivity
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reached the maximum value. In the shorter time, PPy particles were easily isolated from VCF.
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With the increasing of reaction time, the continuous phase of PPy components gradually
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formed on the surface of VCF. However, more reaction time could result in the degradation of
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PPy, reducing the conductivity.
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The influence of Py concentration on the conductivity of PPy/VCF composites was
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investigated at the conditions of reaction time 5h, FeCl3 concentration 0.25 mol/L and SDBS
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concentration 0.03 mol/L (in Fig.7 b). The conductivity of PPy/VCF composites increased
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with the improving of Py concentrations from 0.05 to 0.15 mol/L, but more Py concentrations
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had little effect on the conductivity. The increasing of Py concentrations was facilitated to
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form the continuous PPy layer on VCF. However, the more PPy components could not
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consistently increase the conductivity once the continuous PPy layer had formed.
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FeCl3 concentration was also considered for the conductivity of PPy/VCF composites at the
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conditions of reaction time 5h, Py concentration 0.15 mol/L and SDBS concentration 0.03
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mol/L (in Fig.7 c). At the range of 0-0.35 mol/L, more FeCl3 could improve the conductivity of PPy/VCF composites. On the one hand, FeCl3 as the oxidant could oxidize Py and form the conjugated structure of PPy; on the other hand, Cl- could be used as the dopant of PPy, although it was not main dopant. Therefore, FeCl3 was propitious to improve the conductivity
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of PPy/VCF composites, but the superfluous FeCl3 would separate out from the composites.
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The effect of SDBS concentration on the conductivity of PPy/VCF composites was also
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researched at the conditions of reaction time 5h, Py concentration 0.15 mol/L and FeCl3
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concentration 0.25 mol/L (in Fig.7 d). SDBS was the dopant. When it was added a little, the 10
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conductivity decreased due to the large anion of SDBS, which could compete with FeCl3
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doping. The more SDBS as the dopant improved the conductivity to the maximal value at
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5.26 S/cm. The superfluous SDBS decreased the conductivity again. The more SDBS formed
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the more micelles, where PPy polymerization occurred rather than on the surface of VCF
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surface, so the PPy components reduced on VCF, and the conductivity decreased.
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The conductivity (the maximal value 5.26 S/cm) of PPy/VCF composite was
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competitive with other PPy-based composes such as PPy/lignosulfonate coated cotton
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fabrics (3.03S/cm) (Zhu et al., 2014), PPy-cellulose composite (0.05 S/cm) (Ding,
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Qian, Yu, & An, 2010) and PPy/alginate film (below 2.5 S/cm) (Basavaraja, Jo, Kim,
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Kim, & Huh, 2010).
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The orthogonal experiments (in Tab. 2) were designed to determine the optimal reaction
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conditions. The results of orthogonal experiments were listed in Tab. 3. Of three factors,
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SDBS concentration was determined to be the main factor, followed by Py concentration and
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FeCl3 concentration. The optimal reaction conditions were following: reaction time 5h, Py
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concentration 0.1 mol/L, FeCl3 concentration 0.25 mol/L and SDBS concentration 0 mol/L. 3.4 Washing resistance
The dependence of the conductivity of PPy/VCF composite on washing time is shown in Fig. 8. Before 50 washing times, the conductivity rapidly decreased from 4.2 to 1.5 S/cm, while it
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was stable after more washing. After some PPy polymers, which were not combined well with
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VCF, were washed away, the conductivity of PPy/VCF composite was kept in the high value.
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It indicated that most PPy had good adhesion on VCF.
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4. Conclusions 11
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The conductive PPy/VCF composites were fabricated by polymerizing PPy on VCF template.
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There was good adhesion between PPy and VCF, which was proven with FTIR, TG, XPS and
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washing resistance. PPy components could form the continuous phase on VCF to obtain
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PPy/VCF composites with good conductivity. The morphology and conductivity of the
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PPy/VCF composites were dependent on reaction time, Py concentration, FeCl3 concentration
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and SDBS concentration. And the optimal reaction conditions were determined with
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orthogonal experiments as following: reaction time 5h, Py concentration 0.1 mol/L and FeCl3
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concentration 0.25 mol/L at the reaction temperature of 25 oC. The conductivity of PPy/VCF
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composites still kept at 1.5 S/cm after 50 times washing, and this value was stable for more
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washing. The PPy/VCF composite could become a potential material for conductive textiles,
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dye-sensitized solar cells, energy storage materials, sensors, and materials for water treatment.
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Acknowledgement
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The authors thank science funds of aviation (201329Q2001) for financial supports.
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e-Polymers, 10(1), 253-269.
Wang, C., Zheng, W., Yue, Z., Too, C. O., & Wallace, G. G. (2011).Buckled, stretchable polypyrrole electrodes for battery applications. Advanced Materials, 23(31), 3580-3584.
Yoon, H., Lee, S. H., Kwon, O. S., Song, H. S., Oh, E. H., Park, T. H., & Jang, J. (2009).
297
Polypyrrole nanotubes conjugated with human olfactory receptors: high‐performance
298
transducers for FET ‐ type bioelectronic noses.Angewandte Chemie International
299
Edition, 48(15), 2755-2758.
300
Youssef, A. M., El- Samahy, M. A., Abdel Rehim, M. H. (2012). Preparation of conductive 15
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paper composites based on natural cellulosic fibers for packaging applications.
302
Carbohydrate polymers, 89, 1027- 1032.
304
Youssef, A. M., Elsamahy, M. A., M., Kamel, S. (2012). Structural and electrical properties of paper-polyaniline composite, Carbohydrate Polymers 90, 1003-1007.
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Zhu, L., Wu, L., Sun, Y., Li, M., Xu, J., Bai, Z., & Xu, W. (2014). Cotton fabrics coated with
306
lignosulfonate-doped polypyrrole for flexible supercapacitor electrodes. RSC Advances,
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4(12), 6261-6266.
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Figure Captions
309
Fig. 1 FTIR spectra of VCF (a), PPy (b) and PPy/VCF composite (c).
310
Fig. 2 TG curves of VCF, PPy and PPy/VCF composite.
311
Fig. 3 C1s and O1s XPS core level spectra of VCF (a) and PPy/VCF composites (b), N1s (c)
312
and Cl2p (d) XPS core level spectra of PPy/VCF composites.
313
Fig. 4 SEM images of PPy/VCF composites prepared with different Py concentration: (a) 0.05
314
mol/L, (b) 0.1 mol/L, (c) 0.15 mol/L, (d) 0.2 mol/L.
315
Fig. 5 SEM images of PPy/VCF composites prepared with different FeCl3 concentration: (a)
316
0.06 mol/L, (b) 0.12 mol/L, (c) 0.25 mol/L, (d) 0.37 mol/L.
317
Fig. 6 SEM images of PPy/VCF composites prepared with different SDBS concentration: (a)
318
0 mol/L, (b) 0.01 mol/L, (c) 0.02 mol/L, (d) 0.05 mol/L
319
Fig. 7 The effect of reaction condition on the electrical conductivity of PPy/VCF composites.
320
(a) reaction time, (b) Py concentration, (c) FeCl3 concentration, (d) SDBS concentration.
321
Fig. 8 Washing resistance of PPy/VCF composite.
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Table 1 Chemical composition and doping level of VCF and PPy /VCF composites C (%)
O (%)
N (%)
Cl (%)
total Cl/N (%)
VCF
65.8
34.2
—
—
—
PPy/VCF
74.0
7.8
13.1
5.1
38.8%
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323
Py concentration (mol/L)
FeCl3 concentration (mol/L)
SDBS concentration (mol/L)
Symbol
A
B
C
Level 1
A1=0.05
B1=0.06
C1=0
Level 2
A2=0.1
B2=0.25
C2=0.05
Level 3
A3=0.2
B3=0.40
C3=0.1
cr
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Factors
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Reaction time: 5h.
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Table 2 The factors and levels of orthogonal experiments
19
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325
Table 3 The results of orthogonal experiments
A
B
C
Conductivity (×10-2 S/cm)
1
A1
B1
C1
50.0
2
A1
B2
C2
3
A1
B3
C3
4
A2
B1
C2
5
A2
B2
C3
6
A2
B3
7
A3
B1
8
A3
B2
9
A3
B3
Ij
99.1
52.0
IIj
450.4
IIIj
801.6
Kj
K1=3
Ij/Kj IIj/Kj
326 327
cr
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30.0
1.6
C1
480.0
C2
320.0
950
749.1
40.7
K2=3
K3=3
33
17
317
150
183
120
267
250
14
233
303
d
0.4
C3
360.4
234
9.1
420.0
te
Rang (Dj)
40.0
C1
550
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Number
Reaction time: 5h.
20
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327
Figure 1
1303 1544
11671037
cr
(a) 2921
3437
899
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Transmittance
(c)
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(b)
2917
an
1067 3451 4000
3500
3000
2500
2000
1500
1000
500
-1
Wavenumber (cm )
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328 329
21
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329
Figure 2
80 60
VCF PPy PPy/VCF composite
40 20
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Weight (wt%)
100
0
cr us
-20
VCF PPy PPy/VCF composite
-40
0
100
200
an
DTG(%/min)
0
300
400
500
600
700
800
Temperature(°C)
M
330
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331
22
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Figure 3
C1s
O 1s
(a)
C-OH =C-OH 286.9
(a)
C-OH C-OH = 532.8
C-O-C = 534.4 C-OC
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C=O,C-N C=O = 287.5 O-C=O O-C=O =288.7
280
285
290
295
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cr
C-C = 285.3 C-C
525
530
Binding Energy(eV)
C1s
O1s
an
(b)
C-OH = 284.2 C-OH
535
540
545
Binding Energy(eV)
(b)
C-OC C-O-C = 532.5
M
C=O,C-N C=O = 287.0 O-C=O O-C=O =289.6
C-OH C-OH = 531.2
280
te
d
C-CC-C = 285.3
285
290
295
300
525
530
Binding Energy(eV)
Ac ce p
331
390
392
394
396
398
545
(d) (b)
* Cl* =Cl198.7
-Cl = 200.3
Cl- =Cl197.4
-NH- = 400.3 -NH-
=N- =-N= 399.8
540
Cl 2p
(c)(b)
N1s
535
Binding Energy(eV)
+ -N+- =-N 402.1 -
400
402
404
406
408
410
412
Binding Energy(eV)
190
195
200
205
210
Binding Energy(eV)
23
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Figure 4 （a）
（b）
（c）
（d）
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333
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Figure 5 （a）
（b）
（c）
（d）
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d
335
25
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Figure 6 （a）
（b）
（c）
（d）
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337 338
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338
Figure 7
1.8
(a)
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1.4
cr
1.2 1.0 0.8
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Electrical conductivity(S/cm)
1.6
0.6
an
0.4 0.2 0
5
10
15
20
Time(h)
M
339
d
180
te
140 120
Ac ce p
-2 Electrical conductivity (10 S/m)
160
100
80 60 40 20
(b)
0
-20
0.05
0.10
0.15
0.20
0.25
Py concentration (mol/L)
340
27
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60
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40
30
cr
20
10
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-1 Electrical conductivity (10 S/cm)
50
0
-10 0.00
0.05
0.10
0.15
an
(c)
0.20
0.25
0.30
0.35
0.40
FeCl3 concentration(mol/L)
M
341
d
5.5
4.0
(d)
te
4.5
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Electrical conductivity (S/cm)
5.0
3.5 3.0 2.5 2.0 1.5
0.00
0.01
0.02
0.03
0.04
0.05
SDBS concentration (mol/l)
342
28
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Figure 8
4.5
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3.5
cr
3.0
2.5
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Electrical conductivity(S/cm)
4.0
2.0
an
1.5
1.0 10
20
30
40
50
60
70
Washing times(time)
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Highlights 1. Polypyrrole was polymerized on the surface of viscose fiber. 2. The influence of reaction conditions was investigated in detail. 3. The orthogonal experiments were designed to determine the optimal reaction conditions. 4. The conductivity of composites kept at 1.5 S/cm after washing 50 times or more.
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S0144-8617(15)00289-1 http://dx.doi.org/doi:10.1016/j.carbpol.2015.03.076 CARP 9818
To appear in: Received date: Revised date: Accepted date:
20-11-2014 10-3-2015 11-3-2015
Please cite this article as: Ning, W., Guodong, L., Zhuo, Y., Xingxiang, Z., and Xiaoling, Q.,Conductive polypyrrole/viscose fiber composites, Carbohydrate Polymers (2015), http://dx.doi.org/10.1016/j.carbpol.2015.03.076 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.
Conductive polypyrrole/viscose fiber composites
2
Wang Ning1*, Li Guodong1, Yu Zhuo, Zhang Xingxiang1 and Qi Xiaoling2
3
1 Tianjin Municipal Key Lab of Fiber Modiication and Functional Fiber, School of Material
4
Science and Engineering, Tianjin Polytechnic University, Tianjin 300389, China
5
2 Aviation Key Laboratory of Science and Technology on aeronautical Life-support,
6
Aerospace Life-Support Industries, Xiangyang, 441003, China
7
* Corresponding author. Tel: +86 22 83955816, E-mail: [email protected]
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ABSTRACT:
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Polypyrrole (PPy) was polymerized with pyrrole (Py) as the monomer, FeCl3 as an oxidant
10
and sodium dodecyl benzene sulfonate (SDBS) as the dopant on the surface of viscose fiber
11
(VCF) to prepare the conductive PPy/VCF composites. Fourier transform infrared spectra
12
(FT-IR), Thermal gravimetric analysis (TGA) and X-ray photoelectron spectroscope (XPS)
13
proved that the interaction between PPy and VCF formed in the PPy/VCF composites. Three
14
structures of N atoms (imine, amine and cationic atoms) were found in PPy of PPy/VCF
15
composites. The influence of reaction conditions including reaction time, Py concentration,
16
FeCl3 concentration and SDBS concentration on the morphology and the conductivity of
17
PPy/VCF composites was investigated in detail. The orthogonal experiments were designed to
18
determine the optimal reaction conditions: reaction time 5h, Py concentration 0.1 mol/L and
19
FeCl3 concentration 0.25 mol/L. When PPy/VCF composite was washed 50 times in water,
20
the conductivity still kept at 1.5 S/cm, and this value was stable for more washing.
21
KEYWORDS: conductive; composites; polypyrrole; viscose fiber.
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1. Introduction
23
Conductive polymers such as polyaniline (PANI), polypyrrole (PPy), and their derivatives
24
have been applied on sensors (Yoon et al., 2009), fuel cell (Li et al., 2012), energy storage
25
materials (Wang, Zheng, Yue, Too, & Wallace, 2011), anticorrosive material (Pruna & Pilan,
26
2012) and materials for water treatment (Chandra & Kim, 2011) due to the facile synthesis
27
and flexibility in processing (Liu, Liu, Poyraz, & Zhang, 2011). However, the low solubility,
28
poor mechanical properties and the fabrication difficulty limited the application of these
29
conductive polymers.
30
Now a new attempt is to introduce conductive polymers on the biomacromolecule templates.
31
Starch films were exposed to pyrrole (Py) vapors to promote polymerization of PPy on starch
32
films (Vasques, Domenech, Barreto, & Soldi, 2010). The composites based on natural
33
cellulosic fibers and conductive polymers was prepared using unbleached bagasse and/or rice
34
straw fibers (as cellulosic raw materials) and PANI as conducting polymer (Youssef, El
35
Samahy , & Abdel Rehim, 2012). PANI was incorporated into sheets of paper in order to
37 38 39
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obtain the composites with both the universal properties of paper product and the chemical and electrically conducting properties of PANI (Youssef, Elsamahy, & Kamel, 2012). PPy/lignosulfonate coated cotton fabrics were prepared via in situ oxidation polymerization of Py in the presence of lignosulfonate as both template and dopant (Zhu et al., 2014).
40
PPy/sodium alginate nanospheres were synthesized by oxidative polymerization of Py using
41
sodium alginate as the structural template (Ma et al., 2013). A PANI-gold nanocomposite is
42
chemically synthesized and impregnated in chitosan matrix to immobilize cholesterol oxidase
43
on an indium tin oxide-coated glass plate, which is used for the development of cholesterol 3
Page 3 of 30
biosensors (Srivastava, Srivastava, Nirala, & Prakash, 2014).
45
dopant and the template to prepare PPy/alginate composites (Basavaraja, Jo, Kim, Kim, &
46
Huh, 2010). And PPy nanowires were formed on a DNA template self-assemble into rope-like
47
structures (Pruneanu et al., 2008). Among these templates, cellulose was specially focused on
48
due to the remarkable physical properties, such as a high elastic modulus, a low thermal
49
expansivity, its sustainability and low cost (Shi et al., 2014).
50
Viscose fiber (VCF) is a linear β-1, 4-glycosidically linked polyglucan, which has been
51
man-made in the wetting spinning with chemical stability, biocompatibility and
52
biodegradation (Gurjanova, Ibragimova, Gnezdilov, & Gorshkova, 2007). As a regenerated
53
cellulose fiber, VCF sources from cotton linter or other cellulose sources of wood or bamboo
54
with low cost and good quality (Ramamoorthy, Di, Adekunle, & Skrifvars, 2012). VCF can be
55
used as a carrier for trypsin immobilization to make the enzyme more stable, less
56
immunogenic and toxigenic, and prolong the circulation time in vivo (Nikolic et al., 2014).
57
The silver nanoparticles (AgNPs) imparted a yellowish color to VCFs by the incorporation of
59 60 61
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Alginate was also used as the
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AgNPs into the VCF matrix without the reducing or stabilizing agents. VCF itself acted as a reducer for Ag+ and then stabilized the produced AgNPs (Emam, Mowafi, Mashaly, & Rehan, 2014). VCF was a good support for enzyme and nanoparticles. In this work, Py monomers were adsorbed on VCF surface, and PPy polymers were prepared via in situ oxidation
62
polymerization of Py in the presence of FeCl3 as oxidant and sodium dodecyl benzene
63
sulfonate (SDBS) as the dopant. The adhesion of PPy and VCF was investigated. The effect
64
of reaction conditions on the morphology and the conductivity of PPy/VCF composites were
65
also studied in detail. The orthogonal experiments were designed to determine the optimal 4
Page 4 of 30
reaction conditions. PPy/VCF composites exhibited the excellent conductivity and stability.
67
After washing 50 times in water, the conductivity still kept at 1.5 S/cm.
68
2. Experimental
69
2.1 Materials
70
Py monomer was purchased from Sigma-Aldrich. VCF was provided by Tian Jin Yuanli
71
Chemical Co., China. All solutions were prepared in deionized water. The other reagents were
72
in analytical grade.
73
2.2 Preparation of PPy/VCF composites
74
VCF was soaked in acetone solution, sonicated for 30min, washed with water, and then dried
75
at 60 oC for 12 h in vacuum. 0.5g VCF was added into the SDBS solution. Py was distilled
76
under reduced pressure, added into the SDBS solution, and then stirred for 1 h. FeCl3 solution
77
was added dropwise into the above system. The reaction proceeded at 25 oC. The reaction
78
products were filtrated and washed successively with acetone and deionized water until the
79
filtrate become colorless, and then dried at 40 oC for 24 h in vacuum to obtain PPy/VCF
81 82 83
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composites.
2.3 Characterization
Fourier transform infrared spectra (FT-IR) were recorded with resolution of 4 cm-1 in the method of attenuated total reflection by using a Thermo Nicolet Nexus. Thermal gravimetric
84
(TG) curves were obtained in Universal V3.8 B equipment from TA-Instruments. VCF, PPy
85
and PPy/VCF composite were heated in open alumina pans from 30 to 800℃, under a
86
nitrogen atmosphere, at a heating rate of 15℃/min. X-ray photoelectron spectroscope (XPS)
87
measurements were performed by using K-alpha, ThermoFisher, equipped with an Al Ká 5
Page 5 of 30
radiation source (1486.6 eV). The XPS spectra data was accomplished with the software
89
XPSPEAK4.1. The morphologies of the composites were characterized using a Hitachi
90
S-4800 scanning electron microscope (SEM). They were mounted on aluminium specimen
91
stubs with double-sided adhesive tape and sputter coated with a 20 nm thick gold layer in
92
rarefied argon, using an Emitech K 550 Sputter Coater, with a current of 20 mA for 180s. In
93
the conductivity testing, the samples were pressed into pellet under 26 MPa for 15 minutes.
94
The conductivity was measured at room temperature by a programmable DC voltage/ current
95
detector (four-probe method). Each data shown here is the mean value of the measurement
96
from at least three samples.
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water by a magnetic stirrer at room temperature for 1 h, and dried at 50 oC. This process was
98
repeated for several times for conductivity testing.
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3. Results and discussion
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In the testing of washing resistance, the composite was stirred in
3.1 Characterization of PPy/VCF composites
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The FTIR spectra of VCF, PPy and PPy/VCF composite were shown in Fig. 1. For VCF, the
103 104 105 106
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strong band at 3451 and 2917 cm-1 originated from the stretching of hydroxyl groups and the C-H stretching of CH2, respectively. A strong band at 1067 cm-1 corresponded to the C-O-C pyranose ring skeletal vibration (Hu, Liu, Chen, & Wang, 2011). For PPy polymer, the broad band at 3421 cm−1 was associated with the N-H stretching vibration. The peak at 1544 cm−1 was attributed to C-N asymmetric and ring stretching. The broadband at 1303, 1167, 1037 and
107
899 cm−1 were respectively ascribed to the C-H in-plane deformation vibrations, C-N
108
stretching vibrations, N-H in-plane deformation vibrations, and C-H out-of-plane vibration
109
(Chen et al., 2014). Compared to FTIR spectra of VCF and PPy, the characteristic peaks
110
appeared in the spectra of PPy/VCF composites such as 3437, 2921 and 1544 cm−1, indicating 6
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that PPy chains integrated with VCF to form PPy/VCF composites. The bands of VCF and
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PPy at 900-1200 cm−1 could be overlapped in PPy/VCF composites. And the absorption peak
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at 3451 cm-1 in VCF, ascribed to the NH stretching vibration of PPy (Ramesan, 2013), shifted
114
blue to 3437 cm-1 in PPy/VCF composite. It revealed that the interaction formed due to the
115
intermolecular hydrogen bands between VCF and PPy.
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As shown in Fig. 2, TGA and derivative thermogravimetry (DTG) had been performed for
117
VCF, PPy and PPy/VCF composite. The weight loss was due to the volatilization of the water,
118
and the degradation of products had been monitored as a function of temperature. DTG curves
119
associated with Tmax values at about 350 oC for VCF, which was ascribed to the destruction of
120
VCF into a monomer of D-glucopyranose, while the mass loss of pure PPy was only about
121
40% in the range of thermal degradation. For PPy/VCF composite, the obvious mass loss
122
might be ascribed to the destruction of main chains of both PPy and VCF. In views of much
123
lower mass loss of the composite than VCF, PPy could play a certain protective effect on the
124
thermal decomposition of VCF in PPy/VCF composite duo to the coverage of PPy on VCF
126 127 128
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and the good interaction between PPy and VCF. Fig.3 showed the C1s, O1s, N1s, Cl2p core-level spectra and the relative binding energy (BE) for VCF and PPy/VCF composite, respectively. The chemical compositions of VCF and PPy/VCF composite were also listed in Tab. 1. The carbon content of PPy/VCF composites
129
was 8.2% higher than that of VCF, indicating that VCF was covered with PPy. At the same
130
time, the BE of C1s, O1s for PPy/VCF composite was lower than that of VCF. It implied the
131
interaction between VCF and PPy existed. The previous study (Ding, Qian, Yu, & An, 2010)
132
suggested that the bond between PPy and VCF existed in the form of hydrogen bonding. As 7
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shown in Fig. 3(c) the N1s of the composite could be deconvoluted by assigning BE of 399.8,
134
400.3 and 402.1 eV for imine (-N=), amine (-NH-) and cationic atoms (N+) to illustrate three
135
structures of PPy in PPy/VCF composite. This has also been widely observed in other PPy
136
complexes prepared chemically or electrochemically (Kang, Neoh, Ong, Tan, & Tan, 1991;
137
Castillo-Ortega, Inoue, & Inoue, 1989). In Fig. 3(d) the Cl2p core-level spectra of PPy/VCF
138
composite was resolved with three spin-orbit split doublets (Cl2p3/2 and C12p1/2), with
139
the BE for the Cl2p3/2 peaks lying at about 197.1, 198.6, and 200.1 eV. This readily
140
indicated that the chlorine incorporated exists in three distinct chemical states (Kang ,
141
Neoh, Ong, Tan, & Tan, 1991). Ferric chloride was used as both oxidizing agent and the
142
dopant to improve the conductivity of PPy. The data listed in Tab.1 suggest that the Cl/N
143
ratios (38.8%) in particular, were consistent with previous report (Machida, Miyata, &
144
Techagumpuch, 1989). Howerer, the amount of chlorine incorporated could also vary
145
somewhat with the extent and method of process, although the general line shape of the C12p
146
core-level spectrum remain unchanged.
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3.2 The effect of reaction condition on the morphology of PPy/VCF composites The effect of Py concentration on the morphology of PPy/VCF composites was shown in Fig. 4. At the low Py concentration, the continuous PPy layer grew in the longitudinal grooves of VCF surface, as marked in Fig. 4(a) and (b). The low Py concentration was not enough to
151
form the long PPy chains, which could not form the enough interaction with VCF, so PPy
152
coated on longitudinal grooves rather than flat surface of VCF. With the increasing of Py
153
concentration, the longer and more PPy chains could form the good adhesion, which made
154
PPy cover both the longitudinal grooves and the flat surface of VCF, as exhibited in Fig. 4(c) 8
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and (d).
156
The effect of FeCl3 concentration on the morphology of PPy/VCF composites was illustrated
157
in Fig. 5. At the low concentration of FeCl3, PPy particles were dispersed on the surface of
158
VCF. At the higher concentration of FeCl3, PPy layers continuously formed on the surface of
159
VCF. Because Fe3+could form the complex with Py monomer, FeCl3 could increase the PPy
160
chains with conjugated structure and the size of PPy. Therefore, the continuous PPy layer
161
compactly covered on VCF at the high FeCl3 concentration.
162
The effect of SDBS concentration on the morphology of PPy/VCF composites was shown in
163
Fig. 6. The large PPy granules were poorly dispersed on VCF surface without the addition of
164
SDBS. With the introduction of SDBS, the PPy granules became smaller and the distribution
165
was better on VCF. However, PPy components obviously decreased on VCF surface when
166
SDBS concentration reached to 0.05 mol/L. Here SDBS was used as not only the doping
167
agent but also the surface active agent. The value of critical micelle concentration of SDBS in
168
water is 1.2 × 10-3 mol/L, lower than the initial SDBS concentration (0.01 mol/L). In the
170 171 172
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processing of the composites, SDBS formed a large number of micelles, which adsorbed Py monomer, and became the templates for PPy polymerization. PPy polymerization occurred in the micelles instead of on the surface of VCF surface, so the adhesion of between VCF and PPy polymer became poor. PPy polymer easily fallen off from VCF surface, and PPy
173
components obviously decreased at the high SDBS concentration.
174
3.3 The effect of reaction condition on the conductivity of PPy/VCF composites
175
The effect of reaction time on the conductivity of PPy/VCF composites was studied at the
176
conditions of Py concentration 0.15 mol/L, FeCl3 concentration 0.25 mol/L and SDBS 9
Page 9 of 30
concentration 0.03 mol/L (in Fig.7 a). When the reaction time was 5 h, the conductivity
178
reached the maximum value. In the shorter time, PPy particles were easily isolated from VCF.
179
With the increasing of reaction time, the continuous phase of PPy components gradually
180
formed on the surface of VCF. However, more reaction time could result in the degradation of
181
PPy, reducing the conductivity.
182
The influence of Py concentration on the conductivity of PPy/VCF composites was
183
investigated at the conditions of reaction time 5h, FeCl3 concentration 0.25 mol/L and SDBS
184
concentration 0.03 mol/L (in Fig.7 b). The conductivity of PPy/VCF composites increased
185
with the improving of Py concentrations from 0.05 to 0.15 mol/L, but more Py concentrations
186
had little effect on the conductivity. The increasing of Py concentrations was facilitated to
187
form the continuous PPy layer on VCF. However, the more PPy components could not
188
consistently increase the conductivity once the continuous PPy layer had formed.
189
FeCl3 concentration was also considered for the conductivity of PPy/VCF composites at the
190
conditions of reaction time 5h, Py concentration 0.15 mol/L and SDBS concentration 0.03
192 193 194
cr
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191
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177
mol/L (in Fig.7 c). At the range of 0-0.35 mol/L, more FeCl3 could improve the conductivity of PPy/VCF composites. On the one hand, FeCl3 as the oxidant could oxidize Py and form the conjugated structure of PPy; on the other hand, Cl- could be used as the dopant of PPy, although it was not main dopant. Therefore, FeCl3 was propitious to improve the conductivity
195
of PPy/VCF composites, but the superfluous FeCl3 would separate out from the composites.
196
The effect of SDBS concentration on the conductivity of PPy/VCF composites was also
197
researched at the conditions of reaction time 5h, Py concentration 0.15 mol/L and FeCl3
198
concentration 0.25 mol/L (in Fig.7 d). SDBS was the dopant. When it was added a little, the 10
Page 10 of 30
conductivity decreased due to the large anion of SDBS, which could compete with FeCl3
200
doping. The more SDBS as the dopant improved the conductivity to the maximal value at
201
5.26 S/cm. The superfluous SDBS decreased the conductivity again. The more SDBS formed
202
the more micelles, where PPy polymerization occurred rather than on the surface of VCF
203
surface, so the PPy components reduced on VCF, and the conductivity decreased.
204
The conductivity (the maximal value 5.26 S/cm) of PPy/VCF composite was
205
competitive with other PPy-based composes such as PPy/lignosulfonate coated cotton
206
fabrics (3.03S/cm) (Zhu et al., 2014), PPy-cellulose composite (0.05 S/cm) (Ding,
207
Qian, Yu, & An, 2010) and PPy/alginate film (below 2.5 S/cm) (Basavaraja, Jo, Kim,
208
Kim, & Huh, 2010).
209
The orthogonal experiments (in Tab. 2) were designed to determine the optimal reaction
210
conditions. The results of orthogonal experiments were listed in Tab. 3. Of three factors,
211
SDBS concentration was determined to be the main factor, followed by Py concentration and
212
FeCl3 concentration. The optimal reaction conditions were following: reaction time 5h, Py
214 215 216
cr
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213
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199
concentration 0.1 mol/L, FeCl3 concentration 0.25 mol/L and SDBS concentration 0 mol/L. 3.4 Washing resistance
The dependence of the conductivity of PPy/VCF composite on washing time is shown in Fig. 8. Before 50 washing times, the conductivity rapidly decreased from 4.2 to 1.5 S/cm, while it
217
was stable after more washing. After some PPy polymers, which were not combined well with
218
VCF, were washed away, the conductivity of PPy/VCF composite was kept in the high value.
219
It indicated that most PPy had good adhesion on VCF.
220
4. Conclusions 11
Page 11 of 30
The conductive PPy/VCF composites were fabricated by polymerizing PPy on VCF template.
222
There was good adhesion between PPy and VCF, which was proven with FTIR, TG, XPS and
223
washing resistance. PPy components could form the continuous phase on VCF to obtain
224
PPy/VCF composites with good conductivity. The morphology and conductivity of the
225
PPy/VCF composites were dependent on reaction time, Py concentration, FeCl3 concentration
226
and SDBS concentration. And the optimal reaction conditions were determined with
227
orthogonal experiments as following: reaction time 5h, Py concentration 0.1 mol/L and FeCl3
228
concentration 0.25 mol/L at the reaction temperature of 25 oC. The conductivity of PPy/VCF
229
composites still kept at 1.5 S/cm after 50 times washing, and this value was stable for more
230
washing. The PPy/VCF composite could become a potential material for conductive textiles,
231
dye-sensitized solar cells, energy storage materials, sensors, and materials for water treatment.
232
Acknowledgement
233
The authors thank science funds of aviation (201329Q2001) for financial supports.
234
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Pruna, A., & Pilan, L. (2012).Electrochemical study on new polymer composite for zinc corrosion protection. Composites Part B: Engineering, 43(8), 3251-3257. 14
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Ramamoorthy, S. K., Di, Q., Adekunle, K., & Skrifvars, M. (2012). Effect of water absorption
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on mechanical properties of soybean oil thermosets reinforced with natural fibers.
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Journal of Reinforced Plastics and Composites, 31(18), 1191-1200. Ramesan, M. T. (2013). Synthesis, characterization, and conductivity studies of polypyrrole/
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copper sulfide nanocomposites. Journal of Applied Polymer Science, 128(3), 1540-1546.
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Srivastava, M., Srivastava, S. K., Nirala, N. R., & Prakash, R. (2014). A chitosan-based
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Shi, Z., Gao, H., Feng, J., Ding, B., Cao, X., Kuga, S., & Cai, J. (2014). In Situ Synthesis of
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Robust Conductive Cellulose/Polypyrrole Composite Aerogels and Their Potential
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Application in Nerve Regeneration. Angewandte Chemie International Edition, 53(21),
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Vasques, C. T., Domenech, S. C., Barreto, P. L., & Soldi, V. (2010). Polypyrrole-modified
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starch films: structural, thermal, morphological and electrical characterization.
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Wang, C., Zheng, W., Yue, Z., Too, C. O., & Wallace, G. G. (2011).Buckled, stretchable polypyrrole electrodes for battery applications. Advanced Materials, 23(31), 3580-3584.
Yoon, H., Lee, S. H., Kwon, O. S., Song, H. S., Oh, E. H., Park, T. H., & Jang, J. (2009).
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Polypyrrole nanotubes conjugated with human olfactory receptors: high‐performance
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transducers for FET ‐ type bioelectronic noses.Angewandte Chemie International
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Youssef, A. M., El- Samahy, M. A., Abdel Rehim, M. H. (2012). Preparation of conductive 15
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paper composites based on natural cellulosic fibers for packaging applications.
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Carbohydrate polymers, 89, 1027- 1032.
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Youssef, A. M., Elsamahy, M. A., M., Kamel, S. (2012). Structural and electrical properties of paper-polyaniline composite, Carbohydrate Polymers 90, 1003-1007.
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Zhu, L., Wu, L., Sun, Y., Li, M., Xu, J., Bai, Z., & Xu, W. (2014). Cotton fabrics coated with
306
lignosulfonate-doped polypyrrole for flexible supercapacitor electrodes. RSC Advances,
307
4(12), 6261-6266.
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Figure Captions
309
Fig. 1 FTIR spectra of VCF (a), PPy (b) and PPy/VCF composite (c).
310
Fig. 2 TG curves of VCF, PPy and PPy/VCF composite.
311
Fig. 3 C1s and O1s XPS core level spectra of VCF (a) and PPy/VCF composites (b), N1s (c)
312
and Cl2p (d) XPS core level spectra of PPy/VCF composites.
313
Fig. 4 SEM images of PPy/VCF composites prepared with different Py concentration: (a) 0.05
314
mol/L, (b) 0.1 mol/L, (c) 0.15 mol/L, (d) 0.2 mol/L.
315
Fig. 5 SEM images of PPy/VCF composites prepared with different FeCl3 concentration: (a)
316
0.06 mol/L, (b) 0.12 mol/L, (c) 0.25 mol/L, (d) 0.37 mol/L.
317
Fig. 6 SEM images of PPy/VCF composites prepared with different SDBS concentration: (a)
318
0 mol/L, (b) 0.01 mol/L, (c) 0.02 mol/L, (d) 0.05 mol/L
319
Fig. 7 The effect of reaction condition on the electrical conductivity of PPy/VCF composites.
320
(a) reaction time, (b) Py concentration, (c) FeCl3 concentration, (d) SDBS concentration.
321
Fig. 8 Washing resistance of PPy/VCF composite.
cr
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Ac ce p
322
ip t
308
17
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322
Table 1 Chemical composition and doping level of VCF and PPy /VCF composites C (%)
O (%)
N (%)
Cl (%)
total Cl/N (%)
VCF
65.8
34.2
—
—
—
PPy/VCF
74.0
7.8
13.1
5.1
38.8%
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323
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323
Py concentration (mol/L)
FeCl3 concentration (mol/L)
SDBS concentration (mol/L)
Symbol
A
B
C
Level 1
A1=0.05
B1=0.06
C1=0
Level 2
A2=0.1
B2=0.25
C2=0.05
Level 3
A3=0.2
B3=0.40
C3=0.1
cr
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Factors
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Reaction time: 5h.
Ac ce p
324 325
Table 2 The factors and levels of orthogonal experiments
19
Page 19 of 30
325
Table 3 The results of orthogonal experiments
A
B
C
Conductivity (×10-2 S/cm)
1
A1
B1
C1
50.0
2
A1
B2
C2
3
A1
B3
C3
4
A2
B1
C2
5
A2
B2
C3
6
A2
B3
7
A3
B1
8
A3
B2
9
A3
B3
Ij
99.1
52.0
IIj
450.4
IIIj
801.6
Kj
K1=3
Ij/Kj IIj/Kj
326 327
cr
us an
M
30.0
1.6
C1
480.0
C2
320.0
950
749.1
40.7
K2=3
K3=3
33
17
317
150
183
120
267
250
14
233
303
d
0.4
C3
360.4
234
9.1
420.0
te
Rang (Dj)
40.0
C1
550
Ac ce p IIIj/Kj
ip t
Number
Reaction time: 5h.
20
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327
Figure 1
1303 1544
11671037
cr
(a) 2921
3437
899
us
Transmittance
(c)
ip t
(b)
2917
an
1067 3451 4000
3500
3000
2500
2000
1500
1000
500
-1
Wavenumber (cm )
Ac ce p
te
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328 329
21
Page 21 of 30
329
Figure 2
80 60
VCF PPy PPy/VCF composite
40 20
ip t
Weight (wt%)
100
0
cr us
-20
VCF PPy PPy/VCF composite
-40
0
100
200
an
DTG(%/min)
0
300
400
500
600
700
800
Temperature(°C)
M
330
Ac ce p
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331
22
Page 22 of 30
Figure 3
C1s
O 1s
(a)
C-OH =C-OH 286.9
(a)
C-OH C-OH = 532.8
C-O-C = 534.4 C-OC
ip t
C=O,C-N C=O = 287.5 O-C=O O-C=O =288.7
280
285
290
295
us
cr
C-C = 285.3 C-C
525
530
Binding Energy(eV)
C1s
O1s
an
(b)
C-OH = 284.2 C-OH
535
540
545
Binding Energy(eV)
(b)
C-OC C-O-C = 532.5
M
C=O,C-N C=O = 287.0 O-C=O O-C=O =289.6
C-OH C-OH = 531.2
280
te
d
C-CC-C = 285.3
285
290
295
300
525
530
Binding Energy(eV)
Ac ce p
331
390
392
394
396
398
545
(d) (b)
* Cl* =Cl198.7
-Cl = 200.3
Cl- =Cl197.4
-NH- = 400.3 -NH-
=N- =-N= 399.8
540
Cl 2p
(c)(b)
N1s
535
Binding Energy(eV)
+ -N+- =-N 402.1 -
400
402
404
406
408
410
412
Binding Energy(eV)
190
195
200
205
210
Binding Energy(eV)
23
Page 23 of 30
Figure 4 （a）
（b）
（c）
（d）
M
an
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cr
ip t
332
Ac ce p
te
d
333
24
Page 24 of 30
Figure 5 （a）
（b）
（c）
（d）
M
an
us
cr
ip t
334
te Ac ce p
336
d
335
25
Page 25 of 30
Figure 6 （a）
（b）
（c）
（d）
M
an
us
cr
ip t
336
Ac ce p
te
d
337 338
26
Page 26 of 30
338
Figure 7
1.8
(a)
ip t
1.4
cr
1.2 1.0 0.8
us
Electrical conductivity(S/cm)
1.6
0.6
an
0.4 0.2 0
5
10
15
20
Time(h)
M
339
d
180
te
140 120
Ac ce p
-2 Electrical conductivity (10 S/m)
160
100
80 60 40 20
(b)
0
-20
0.05
0.10
0.15
0.20
0.25
Py concentration (mol/L)
340
27
Page 27 of 30
60
ip t
40
30
cr
20
10
us
-1 Electrical conductivity (10 S/cm)
50
0
-10 0.00
0.05
0.10
0.15
an
(c)
0.20
0.25
0.30
0.35
0.40
FeCl3 concentration(mol/L)
M
341
d
5.5
4.0
(d)
te
4.5
Ac ce p
Electrical conductivity (S/cm)
5.0
3.5 3.0 2.5 2.0 1.5
0.00
0.01
0.02
0.03
0.04
0.05
SDBS concentration (mol/l)
342
28
Page 28 of 30
343
Figure 8
4.5
ip t
3.5
cr
3.0
2.5
us
Electrical conductivity(S/cm)
4.0
2.0
an
1.5
1.0 10
20
30
40
50
60
70
Washing times(time)
Ac ce p
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d
M
344 345
29
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cr
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Highlights 1. Polypyrrole was polymerized on the surface of viscose fiber. 2. The influence of reaction conditions was investigated in detail. 3. The orthogonal experiments were designed to determine the optimal reaction conditions. 4. The conductivity of composites kept at 1.5 S/cm after washing 50 times or more.
Ac ce p
345 346 347 348 349 350
30
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