Synthesis of PEDOT:Pt Hybrid Fibers and PEDOT:PSS Hybrid Fibers

6 hours ago - I&EC Process Design and Development · - I&EC Fundamentals · - Product ... Education · Journal of Chemical Information and Modeling...
1 downloads 0 Views 1MB Size
Subscriber access provided by READING UNIV

Interfaces: Adsorption, Reactions, Films, Forces, Measurement Techniques, Charge Transfer, Electrochemistry, Electrocatalysis, Energy Production and Storage

Synthesis of PEDOT:Pt Hybrid Fibers and PEDOT:PSS Hybrid Fibers by AC-Bipolar Electropolymerization Yuki Koizumi, Masato Ohira, Tempei Watanabe, Hiroki Nishiyama, Ikuyoshi Tomita, and Shinsuke Inagi Langmuir, Just Accepted Manuscript • DOI: 10.1021/acs.langmuir.8b00408 • Publication Date (Web): 11 Jun 2018 Downloaded from http://pubs.acs.org on June 12, 2018

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Langmuir

Synthesis

of

PEDOT:PSS

PEDOT:Pt Hybrid

Hybrid

Fibers

by

Fibers

and

AC-Bipolar

Electropolymerization Yuki Koizumi,† Masato Ohira,† Tempei Watanabe ‡ Hiroki Nishiyama,‡ Ikuyoshi Tomita,‡ and Shinsuke Inagi*,‡ †

Department of Electronic Chemistry, Interdisciplinary Graduate School of Science and

Engineering, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 2268502, Japan ‡

Department of Chemical Science and Engineering, School of Materials and Chemical

Technology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 2268502, Japan

ACS Paragon Plus Environment

1

Langmuir 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ABSTRACT:

Alternating

current

(AC)-bipolar

Page 2 of 22

electropolymerization

of

3,4-

ethylenedioxythiophene (EDOT) was performed in the presence of hexachloroplatinate ([PtCl6]2– ) or polystyrene sulfonate (PSS). We demonstrated that both [PtCl6]2– and PSS were successfully incorporated into electrogenerated PEDOT as dopants to offer hybrid fibers composed of (i) PEDOT and platinum nanoparticles (PtNPs) (PEDOT:Pt hybrid fibers) and (ii) PEDOT and PSS (PEDOT:PSS hybrid fibers), respectively, in one-step grown from very edges of Au wires used as bipolar electrodes (BPEs).

Keywords: Electrochemistry, Bipolar electrode, Conducting polymer, Polymer fiber, Nanoparticle, Doping

ACS Paragon Plus Environment

2

Page 3 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Langmuir

Introduction Conducting polymers containing π-conjugated aromatic rings with p-orbital overlaps throughout the polymer main chains are an attractive class of materials for their potential use in organic electronic devices.1–2 Electrochemical polymerization (electropolymerization) of aromatic monomers including pyrrole and thiophene derivatives is commonly regarded as a facile method to obtain conducting polymers as deposited films on a working electrode since electron transfer of monomer and its coupling reaction lead to insoluble polymeric products adjacent to the surface of the electrode.3–5 In this context, we have recently developed alternating current (AC)-bipolar electropolymerization as a novel approach for synthesis of conducting polymer microfibers.6,7 In a low concentration of supporting electrolytes, IR drop of the electrolytic solution induces a potential difference between both ends of a conducting material placed between feeder electrodes.8–10 Under such circumstances, the conductive material behaves as a bipolar electrode (BPE) to perform an oxidation reaction at the anodic side coupled with a reduction reaction at the cathodic side simultaneously when a sufficient voltage is applied between the feeder electrodes.11–16 In the previous work, an Au wire was utilized as a BPE driven by an electric field between a pair of Pt feeder electrodes in tetrabutylammonium perchlorate (Bu4NClO4)/acetonitrile (MeCN) containing 3,4-ethylenedioxythiophene (EDOT) and benzoquinone (BQ) (Figure 1).6,7 Based on the principle of bipolar electrochemistry, a couple of redox reactions, i.e., an oxidation of EDOT and a sacrificial reduction of BQ, proceed when an applied potential difference between the termini of a BPE (∆VBPE) is higher than the onset potential differences (∆Vmin = 1.82 V). The

ACS Paragon Plus Environment

3

Langmuir 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 4 of 22

former oxidative reaction forms radical cations of EDOT to afford a polymer product via repeating C-C coupling and deprotonation; thus, it leads to the formation of PEDOT at the anodic side of the BPE. On the other hand, the latter sacrificial reductive reaction forms hydroquinone (HQ) to compensate the total amount of electron passed on both the anodic and cathodic sides of BPE. On the application of AC voltage between the feeder electrodes, electrogenerated poly(3,4-ethylenedioxythiophene) (PEDOT) was obtained as microfibers (φ = 3–5 mm) grown from both the ends of the BPE. Under the bipolar electrochemical conditions, the resultant polymer is typically in the doped state having positive charges on its polymer backbone so that it can be electrophoresed under the influence of the external electric field. On this account, it results in the anisotropic precipitation of PEDOT with a fiber structure.

Figure 1. Schematic illustration of the setup for bipolar electropolymerization of EDOT: The potential difference at the electrode/solution interface varies across the length of a BPE according to the potential gradient applied to the solution, thus the overpotentials (∆VBPE) can drive oxidative polymerization of EDOT and sacrificial reduction of BQ at anodic and cathodic terminal of the BPE, respectively.

ACS Paragon Plus Environment

4

Page 5 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Langmuir

In order to expand the applicable scope of our method, we herein demonstrate the facile and template-free synthesis of conducting polymer hybrid fibers on BPEs by oxidative electropolymerization of EDOT in the presence of hexachloroplatinate ([PtCl6]2–) or polystyrene sulfonate (PSS), instead of perchlorate (ClO4–) used in the previous work. Although these three anions could act as dopants against electrogenerated PEDOT, [PtCl6]2– and PSS imparted the additional functionalities to PEDOT fibers. After the polarity changed to negative, electroreduction of doped [PtCl6]2– proceeded adjacent to the polymer backbones to provide welldispersed platinum nanoparticles (PtNPs) inside the fibers, which showed the activity for adsorption and desorption of hydrogen atoms. PSS was also incorporated into PEDOT fibers to present synergistic enhancement in rigidity. Thus, AC-bipolar electrolysis would be the prominent methodology for the synthesis of PEDOT hybrid fibers.

Results and Discussion Synthesis of PEDOT:Pt Hybrid Fibers For synthesis of PEDOT:Pt hybrid fibers, Au wires (φ = 50 µm, 20 mm length) were utilized as BPEs, which were placed in line between a pair of Pt feeder electrodes (20 mm × 20 mm, distance: 60 mm), and 1 mM hexachloroplatinic(IV) acid (H2PtCl6)/MeCN containing 50 mM EDOT was filled in an electrolytic cell (Figure S1). To carry out anodic and cathodic reactions simultaneously on BPEs, which are oxidative electropolymerization of EDOT and electroreduction of [PtCl6]2–, ∆VBPE must be higher than the onset potential difference of their redox couples (∆Vmin = 1.09 V, Figure 2a). When we applied AC voltage (E = 30 V, ∆VBPE = 5.0 V, 5 Hz, square wave alternating in polarity) between two feeder electrodes, several polymer fibers were observed to propagate dendritically from the end of each Au wire in a similar way to the

ACS Paragon Plus Environment

5

Langmuir 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 6 of 22

previous work,6 and these fibers bridged the 1 mm gap for 5 min (Figure 2b). It has been recognized that a metal ion having a positive reduction potential, once in contact, can be spontaneously reduced by an aromatic monomer to form zero-valent metal.17 For example, EDOT can reduce tetrachloroauric(III) acid in THF solution giving gold nanoparticles.18 However, no color change was observed in the electrolyte containing H2PtCl6 and EDOT during the AC-bipolar electrolysis in this study. After the AC-bipolar electropolymerization, the PEDOT:Pt hybrid fibers were successfully transferred onto a carbon tape after carefully washed with MeCN and dried. Field emission scanning electron microscopy (FE-SEM) images revealed that the PEDOT:Pt hybrid fiber was composed of the trunks and buds in a linear fashion, but its diameter and surface shape were slightly different from what we previously reported on PEDOT fibers (Figure 2c). The PEDOT:Pt hybrid fiber had a diameter of 6.5–18 µm and a rough surface. Furthermore, the PtNPs with a diameter of 5–10 nm were well-dispersed in the fibers. These PtNPs were also observed by transmission electron microscope (TEM) (Figure 2d). The energy-dispersive X-ray (EDX) analysis showed that not only sulfur derived from thiophene rings of EDOT, but also platinum derived from the PtNPs and [PtCl6]2– existed in PEDOT:Pt hybrid fibers (Figure 2e).

ACS Paragon Plus Environment

6

Page 7 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Langmuir

Figure 2. (a) Schematic illustration of the electrochemical reactions in the AC-bipolar electrolysis including oxidative polymerization of EDOT and sacrificial reduction of [PtCl6]2– with Au wires as BPEs. (b) Optical microscope image of PEDOT:Pt hybrid fibers bridging the 1 mm gap between Au wires (∆VBPE = 10 V, 5 min, 5 Hz). (c) FE-SEM images of the PEDOT:Pt hybrid fibers. (d) TEM image of PEDOT:Pt hybrid fibers. (e) FE-TEM image of PEDOT:Pt hybrid fibers and corresponding EDX mapping of S and Pt.

The elemental states of the PEDOT:Pt hybrid fiber were also investigated by X-ray photoelectron spectroscopy (XPS) as shown in Figure 3 and Figure S6. All spectra were referenced to the binding energy of C1s for the C−C bond as 284.8 eV. The survey spectrum exhibited C1s, S2p and Pt4f peaks (Figure 3a). The high-resolution XPS spectrum of Pt4f

ACS Paragon Plus Environment

7

Langmuir 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 8 of 22

displayed three peaks at 71.51 eV, 74.57 eV, and 76.85 eV (Figure 3b). The first and second ones were corresponded to doublet of metallic Pt0 4f7/2 and 4f5/2, respectively, and the last one was assigned to Pt4+ 4f7/2 of [PtCl6]2–.19

Figure 3. XPS survey spectra for PEDOT:Pt hybrid fibers. (b) Deconvoluted Pt4f XPS spectrum for PEDOT:Pt hybrid fibers.

We also demonstrated the synthesis of PEDOT:Ag hybrid fibers by replacing H2PtCl6 as silver(I) tetrafluoroborate (AgBF4) similarly to the method above (Figure S5). The highresolution XPS spectrum of Ag3d displayed two peaks of metallic Ag0 at 368.06 eV (Ag03d5/2) and 374.06 eV (Ag03d3/2), and two small peaks of Ag+ at 369.06 eV (Ag+3d5/2) and 375.46 eV

ACS Paragon Plus Environment

8

Page 9 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Langmuir

(Ag+3d3/2), indicating that Ag+ was little incorporated in the PEDOT:Ag hybrid fiber (Figure S7).20 Furthermore, the FE-SEM images showed that the dispersity of silver nanoparticles (AgNPs) in the PEDOT:Ag hybrid fibers was not so high as that of PtNPs in the PEDOT:Pt hybrid fibers (Figure S5c). Besides, the AgNPs with a diameter of 35–153 nm, which was relatively larger than that of the PtNPs, were electrodeposited at the surface of the fibers preferentially. These results should be caused by electrostatic repulsion between electrogenerated PEDOT and Ag+. Ag+ could not act as a dopant against the electrogenerated PEDOT so that the electro-reduction of Ag+ preferentially proceeded at the surface of PEDOT fibers; thus, the generated AgNPs were not protected by surrounding PEDOT, which resulted in the aggregation of AgNPs easily to form large particles with a wide distribution in size.21,22 Finally, electrochemical properties of the PEDOT:Pt hybrid fibers were investigated by using cyclic voltammetry (CV). According to the CV measurement for the PEDOT:Pt hybrid fiber conducted on a glassy carbon (GC) electrode in 0.1 M H2SO4/H2O, the redox peaks were observed between −0.15 and 0.15 V vs. SCE due to the adsorption and the desorption of hydrogen atoms on the surfaces of PtNPs, in addition to the broad redox response of PEDOT in the potential range (Figure 4).23,24

ACS Paragon Plus Environment

9

Langmuir 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 10 of 22

Figure 4. Cyclic voltammograms of (a) PEDOT fibers (blue line), (b) PEDOT:Pt hybrid fibers (orange line ), and (c) background (gray line) on a glassy carbon electrode in 0.1 M H2SO4/H2O at a scan rate of 100 mV/s.

Propagation Mechanism of PEDOT:Pt Hybrid Fibers A possible propagation mechanism of PEDOT:Pt hybrid fibers is described in Figure 5a. The basic principle to form conducting polymer fibers from both sides of a BPE is the same as we previously reported.6,7 In the p-doped state of electrogenerated PEDOT, an anionic dopant ([PtCl6]2–) must be incorporated into the polymer chain to compensate the electro-neutrality. In the next step, these anions are reduced to form well-dispersed PtNPs adjacent to the polymer backbone as soon as the polarity changes to negative. Thanks to the cationic charges on PEDOT, it acts as a template to facilitate metal particles nucleation, which leads to the well-dispersed

ACS Paragon Plus Environment

10

Page 11 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Langmuir

PtNPs being trapped within the growing polymer fiber structure. The reports on the electrochemical methods utilizing alternating electro-oxidative doping of PEDOT with [PtCl6]2– and subsequent electro-reduction of the dopant to impregnate PEDOT with well-dispersed PtNPs also bear out our hypothesis.25,26 On the other hand, in the case using AgBF4 as a supporting electrolyte, Ag+ is prevented from incorporation into the electrogenerated PEDOT due to the electrostatic repulsion (Figure 5b). After the polarity changes to negative, an electro-reduction of Ag+ preferentially proceeds on the surface of PEDOT fibers, which stems from a sufficiently high conductivity of fibers to play as a part of BPE. Thus, electrogenerated AgNPs are easily aggregated to form large particles having a wide distribution in size, which are confined largely to the surface of fibers with unevenly distributed manner.22

Figure 5. Possible propagation mechanism for (a) PEDOT:Pt hybrid fibers and (b) PEDOT:Ag hybrid fibers in AC-bipolar electropolymerization.

ACS Paragon Plus Environment

11

Langmuir 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 12 of 22

Synthesis of PEDOT:PSS Hybrid Fibers For synthesis of PEDOT:PSS hybrid fibers, similar experimental configuration was employed except for electrolyte, which is composed of 0.1 wt% of poly(sodium 4-styrenesulfonate) (PSSNa, Mw~70,000) dispersed in water containing 10 mM EDOT. During the functioning of the Au wires (φ = 30 µm, 10 mm length) as BPEs, the electropolymerization of EDOT took place at the anodic side, while the sacrificial reduction of water simultaneously proceeded at the cathodic side (Figure 6a). From these redox reactions, ∆Vmin can be estimated as 2.20 V. It is also necessary to apply higher frequency of AC voltage to minimize the effect of the gas formation, which disturbs the propagation of PEDOT fibers from BPEs. The propagation of polymer fibers was initiated from the end of the Au wires by applying AC voltage (E = 50 V, ∆VBPE = 6.6 V, 100 Hz, square wave alternating in polarity) between the feeder electrodes. The propagation rate was too sluggish to bridge the 1 mm gap, but they were more rigid than the original PEDOT fibers so that they were easily picked out from the electrolytic cell (Figure 6b). We also performed the AC-bipolar electropolymerization by replacing PSSNa with sodium ptoluenesulfonate (TsNa) for comparison, and found that the resultant polymer fibers were so fragile that it was difficult to be picked out from the electrolytic cell (Figure S8). PEDOT:PSS hybrid fibers were successfully transferred onto a carbon tape after carefully washed with water and dried. Figure 6c shows SEM images of the PEDOT:PSS hybrid fibers. The PEDOT:PSS hybrid fiber had a diameter of 2.5–8.0 µm and a smooth surface. The CV of PEDOT:PSS fiber was conducted to show a broad redox response (Figure S9).

ACS Paragon Plus Environment

12

Page 13 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Langmuir

Figure 6. (a) Schematic illustration of the electrochemical reactions in the AC-bipolar electrolysis including oxidative polymerization of EDOT and sacrificial reduction of H2O with Au wires as BPEs. (b) optical microscope image of PEDOT:PSS hybrid fibers grown form Au wires (∆VBPE = 6.6 V, 2 min, 100 Hz), and (c) SEM images of the PEDOT:PSS hybrid fibers.

Figure 7 illustrates the Fourier transform infrared (FTIR) spectrum of the PEDOT:PSS hybrid fibers. The vibrations at 1185 and 1164 cm–1 were assigned to the C-O-C bond stretch in the ethylenedioxy group. The peaks at 1509 and 1317 cm–1 were corresponding to the ring stretching of the thiophene ring. The weak vibration at 1053 cm–1 was conceivably due to the C-O stretch. Peaks at 979, 931, and 834 cm–1 were assigned to thiophene C-S bond stretching. The peak at 1090 cm–1 was corresponding to the sulfone groups -SO2 and -SO3– in PSS.27,28

ACS Paragon Plus Environment

13

Langmuir 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 14 of 22

Figure 7. FTIR spectrum of PEDOT:PSS hybrid fibers.

Thermal gravimetric analysis (TGA) was also demonstrated for the PEDOT:PSS hybrid fibers, the PEDOT fibers doped with ClO4–, and commercially available PSSNa (Figure 8). The initial 9.9 % weight loss of PEDOT:PSS hybrid fibers until 150 °C was attributed to the loss of water. Both PEDOT fibers and PEDOT:PSS hybrid fibers were fairly stable up to 280 °C, but the latter showed slightly better thermal tolerance than the former.29,30 These data suggested that a little amount of PSS was successfully incorporated into PEDOT fibers as a dopant. Thus, the handling of the tough hybrid fiber was easy as described above.

ACS Paragon Plus Environment

14

Page 15 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Langmuir

Figure 8. TGA curves of PEDOT:PSS hybrid fibers, PEDOT fibers, and PSSNa.

Propagation Mechanism of PEDOT:PSS Hybrid Fibers A possible propagation mechanism of PEDOT:PSS hybrid fibers is described in Figure 9. During the AC-bipolar electropolymerization, the PEDOT fiber propagates to incorporate PSS as a dopant with electrostatic interaction. After the polarity changes, PEDOT leads to be neutralized, simultaneously with the electro-reduction of water, so that counter parts of sulfonate in PSS make ion pair with sodium ions. However, the PEDOT is not completely dedoped during the iterative polarity changes. Therefore, the PSS is still incorporated in the PEDOT fiber.

ACS Paragon Plus Environment

15

Langmuir 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 16 of 22

Figure 9. Possible propagation mechanism for the PEDOT:PSS hybrid fibers in AC-bipolar electropolymerization.

Conclusions The AC-bipolar electropolymerization of EDOT in the presence of [PtCl6]2– and PSS successfully produced PEDOT:Pt hybrid fibers and PEDOT:PSS hybrid fibers, respectively, from both ends of Au wires acting as BPEs. The electrophoresis of charged polymers in an external electric field played an important role to construct a polymer fiber structure. The electrostatic interaction between electrogenerated PEDOT and anionic dopants also enabled to incorporate PtNPs and PSS into the fiber structures. Furthermore, these hybrid fibers showed better physical properties than those of the conventional PEDOT fibers. Such spontaneous propagation of conducting polymer hybrid fibers without templates has a potential interest for application in electronic devices.

ACS Paragon Plus Environment

16

Page 17 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Langmuir

ASSOCIATED CONTENT Supporting Information The Supporting Information is available free of charge on the ACS Publications website. Experimental section (materials and instruments). Cell configuration. Estimation of ∆VBPE. Estimation of cell factors and∆VBPE. AC-bipolar Electropolymerization for Synthesis of PEDOT:Ag Hybrid Fibers. XPS Spectra of PEDOT:Pt Hybrid Fibers. XPS Spectra of PEDOT:Ag Hybrid Fibers. Cyclic Voltammetry Measurements for PEDOT Fibers and PEDOT:Pt Hybrid Fibers. AC-bipolar Electropolymerization for Synthesis of PEDOT:Ts Hybrid Fibers.

AUTHOR INFORMATION Corresponding Author *E-mail: [email protected] (S.I.)

ACKNOWLEDGMENT This research was supported by JSPS KAKENHI (Grant Numbers JP17H03095 and JP17J01209), and research grants from The Murata Science Foundation and Casio Science Promotion Foundation.

ACS Paragon Plus Environment

17

Langmuir 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 18 of 22

REFERENCES (1) Skotheim, T. A.; Reynolds, J. R. Handbook of Conducting Polymers, 3rd ed.; CRC Press: Boca Raton, 2007. (2) Inzelt, G. Conducting Polymers–A New Era of Electrochemistry; Springer: Heidelberg, 2008. (3) Beaujuge, P. M.; Reynolds, J. R. Color Control in π-Conjugated Organic Polymers for Use in Electrochromic Devices. Chem. Rev. 2010, 110, 268–310. (4) Heinze, J.; Frontana-Uribe, B. A.; Ludwigs, S. Electrochemistry of Conducting Polymers– Persistent Models and New Concepts. Chem. Rev. 2010, 110, 4724–4771. (5) Fuchigami, T.; Atobe, M.; Inagi, S. Fundamentals and Applications of Organic Electrochemistry: Synthesis, Materials, Devices; Wiley: Hoboken, 2014. (6) Koizumi, Y.; Shida, N.; Ohira, M.; Nishiyama, H.; Tomita, I.; Inagi, S. Electropolymerization on Wireless Electrodes towards Conducting Polymer Microfibre Networks. Nat. Commun. 2016, 7, 10404. (7) Ohira, M.; Koizumi, Y.; Nishiyama, H.; Tomita, I.; Inagi, S. Synthesis of Linear PEDOT Fibers by AC-Bipolar Electropolymerization in a Micro Space. Polym. J. 2017, 49, 163–167. (8) Fosdick, S. E.; Knust, K. N.; Scida, K.; Crooks, R. M. Bipolar Electrochemistry. Angew. Chem. Int. Ed. 2013, 52, 10438–10456. (9) Loget, G.; Zigah, D.; Bouffier L.; Sojic, N.; Kuhn, A. Bipolar Electrochemistry: From Materials Science to Motion and Beyond. Acc. Chem. Res. 2013, 46, 2513–2523.

ACS Paragon Plus Environment

18

Page 19 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Langmuir

(10) Inagi, S. Fabrication of Gradient Polymer Surfaces Using Bipolar Electrochemistry. Polym. J. 2015, 48, 39–44.

(11) Bradley, J. –C.; Chen, H. –M.; Crawford, J.; Eckert, J.; Ernazarova, K.; Kurzeja, T.; Lin, M.; McGee, M.; Nadler, W.; Stephens, S. G. Creating Electrical Contacts between Metal Particles Using Directed Electrochemical Growth. Nature 1997, 389, 268–271. (12) Ulrich, C.; Andersson, O.; Nyholm, L.; Björefors, F. Formation of Molecular Gradients on Bipolar Electrodes. Angew. Chem. Int. Ed. 2008, 47, 3034–3036. (13) Inagi, S.; Ishiguro, Y.; Atobe, M.; Fuchigami, T. Bipolar Patterning of Conducting Polymers by Electrochemical Doping and Reaction. Angew. Chem. Int. Ed. 2010, 49, 10136– 10139. (14) Loget, G.; Lapeyre, V.; Garrigue, P.; Warakulwit, C.; Limtrakul, J.; Delville, M. –H.; Kuhn, A. Versatile Procedure for Synthesis of Janus-Type Carbon Tubes. Chem. Mater. 2011, 23, 2595–2599. (15) Mayorga-Martinez, C. C.; Khezri, B.; Eng, A. Y. S.; Sofer, Z.; Ulbrich, P.; Pumera, M. Bipolar Electrochemical Synthesis of WS2 Nanoparticles and Their Application in Magneto‐ Immunosandwich Assay. Adv. Funct. Mater. 2016, 26, 4094–4098. (16) Ali Fattah, Z.; Bouffier, L.; Kuhn, A. Indirect Bipolar Electrodeposition of Polymers for the Controlled Design of Zinc Microswimmers. Appl. Mater. Today 2017, 9, 259–265.

ACS Paragon Plus Environment

19

Langmuir 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 20 of 22

(17) Xu, P.; Han, X.; Zhang, B.; Du, Y.; Wang, H. –L. Multifunctional Polymer-Metal Nanocomposites via Direct Chemical Reduction by Conjugated Polymers. Chem. Soc. Rev. 2014, 43, 1349–1369. (18) Li, X.; Li, Y.; Tan, Y.; Yang, C.; Li, Y. Self-Assembly of Gold Nanoparticles Prepared with 3,4-Ethylenedioxythiophene as Reductant. J. Phys. Chem. B 2004, 108, 5192–5199. (19) Wang, S. –J.; Park, H. –H. Properties of One-Step Synthesized Pt Nanoparticle-Doped Poly(3,4-ethylenedioxythiophen):poly(styrenesulfonate) Hybrid Films. Thin Sold Films 2010, 518, 7185–7190. (20) Yoshida, R.; Matsumura, T.; Nakahodo, T.; Fujihara, H. Fabrication and Metal-Enhanced Fluorescence of Plasmonic Hybrid Nanotubes Consisting of Polythiophene and Silver Nanoparticles. Chem. Lett. 2015, 44, 135–137. (21) Zhou, Y.; Itoh, H.; Uemura, T.; Naka, K.; Chujo, Y. Synthesis of Novel Stable Nanometer-Sized Metal (M = Pd, Au, Pt) Colloids Protected by a π-Conjugated Polymer. Langmuir 2002, 18, 277–283. (22) Sih, B. C.; Wolf, M. O. Metal Nanoparticle–Conjugated Polymer Nanocomposites. Chem. Commun. 2005, 3375–3384. (23) Lupu, S.; Lakard, B.; Hihn, J. –Y.; Dejeu, J. Novel in situ Electrochemical Deposition of Platinum Nanoparticles by Sinusoidal Voltages on Conducting Polymer Films. Synth. Met. 2012, 162, 193–198.

ACS Paragon Plus Environment

20

Page 21 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Langmuir

(24) Fernandez-Blanco, C.; Ibañez, D.; Colina, A.; Ruiz, V.; Heras, A. Spectroelectrochemical Study of the Electrosynthesis of Pt Nanoparticles/Poly(3,4-(ethylenedioxythiophene) Composite. Electrochim. Acta 2014, 145, 139–147. (25) Armel, V.; Winther-Jensen, O.; Kerr, R.; MacFarlane, D. R.; Winther–Jensen, B. Designed Electrodeposition of Nanoparticles inside Conducting Polymers. J. Mater. Chem. 2012, 22, 19767–19773. (26) Ramirez, M. R. A.; del Valle, M. A.; Armijo, F.; Diaz, F. R.; Angelica Pardo, M.; Ortega, E. Enhancement of Electrodes Modified by Electrodeposited PEDOT-Nanowires with Dispersed Pt Nanoparticles for Formic Acid Electro-Oxidation. J. Appl. Polym. 2017, 134, 44723. (27) Nagarajan, S.; Kumar, J.; Bruno, F. F.; Samuelson, L. A.; Nagarajan, R. Biocatalytically Synthesized Poly(3,4-ethylenedioxythiophene). Macromolecules 2008, 41, 3049–3052. (28) Chen, T.; Qiu, J.; Zhu, K.; Li, J.; Wang, J.; Li, S.; Wang, Z. Ultra High Permittivity and Significantly Enhanced Electric Field Induced Strain in PEDOT:PSS–RGO@PU Intelligent Shape-Changing Electro-Active Polymers. RSC. Adv. 2014, 4, 64061–64067. (29)

Kiebooms,

R.;

Aleshin,

A.;

Wudl,

F.;

Heeger,

A.

Doped

Poly(3,4-

ethylenedioxythiophene) Films: Thermal, Electromagnetical and Morphological Analysis. Synth. Met. 1999, 101, 436–437. (30) Friedel, B.; Keivanidis, P. E.; Brenner, T. J. K.; Abrusci, A.; McNeil, C. R.; Friend, R. H. Greenham, N. C. Effects of Layer Thickness and Annealing of PEDOT:PSS Layers in Organic Photodetectors. Macromolecules 2009, 42, 6741–6747.

ACS Paragon Plus Environment

21

Langmuir 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 22 of 22

SYNOPSIS TOC

ACS Paragon Plus Environment

22