Highly conductive nanocomposite enabled by an accordion-like

Subscriber access provided by Kaohsiung Medical University

Article

Highly conductive nanocomposite enabled by an accordion-like graphene network for flexible heating films and supercapacitors Lijun Yang, Wei Weng, Junjie Yang, Yang Zhang, Yunxia Liang, Xiaogang Luo, and Meifang Zhu ACS Appl. Nano Mater., Just Accepted Manuscript • DOI: 10.1021/acsanm.8b00997 • Publication Date (Web): 08 Aug 2018 Downloaded from http://pubs.acs.org on August 14, 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 20 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

ACS Applied Nano Materials

Highly Conductive Nanocomposite Enabled by an Accordion-like Graphene Network for Flexible Heating Films and Supercapacitors Lijun Yang, Wei Weng*, Junjie Yang, Yang Zhang, Yunxia Liang, Xiaogang Luo, Meifang Zhu*

State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, 2999 North Renmin Road, Shanghai 201620, China;

Author information: First author: [email protected] (Yang Lijun) *Corresponding authors. Emails: [email protected] (Weng Wei) [email protected]. (Zhu Meifang)

ACS Paragon Plus Environment

ACS Applied Nano Materials 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

Highly Conductive Nanocomposite Enabled by an Accordion-like Graphene Network for Flexible Heating Films and Supercapacitors Lijun Yang, Wei Weng*, Junjie Yang, Yang Zhang, Yunxia Liang, Xiaogang Luo, Meifang Zhu*

State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, 2999 North Renmin Road, Shanghai 201620, China;

ABSTRACT Graphene reinforced polymer nanocomposites can have favorable electrical properties, making them promising in electromagnetic, electrochromic and photovoltaic devices. Using graphene to fabricate nanocomposites with specific electrical properties requires that the dispersion of graphene in polymer matrix is well controlled, which however remains a big challenge. Here, we propose two intriguing designs, i.e., slightly oxidizing graphene sheets and hot drawing nanocomposites, resulting in a uniform, dense and highly aligned graphene network. The achieved conductivity of nanocomposites is as high as 25 S m-1 at 6.25 wt% of graphene, which is 8 and 2 orders of magnitude higher than those of polymer matrix and nanocomposites without hot drawing, respectively. Furthermore, prototypes of heating films and flexible supercapacitors made of the highly conductive nanocomposites both exhibit high performance. KEYWORDS: graphene, aligned, nanocomposite, conductive, flexible electronics


Page 2 of 20

Page 3 of 20 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


INTRODUCTION Conductive polymer nanocomposites (CPNCs) are of increasing significance and witness a fast growth over the last decade.1,2 The combined merits of high strength, flexibility, conductivity and light weight render CPNCs extremely promising in electromagnetic interference shielding, anti-static field, energy and flexible electronics.3-7 A large category of conductive fillers have been utilized, including metal nanoparticles/nanowires, carbon black (CB), graphite flake, carbon nanotube (CNT) and graphene.8-12 In light of the fact that large aspect ratios of conductive fillers lead to high conductive performance of CPNCs, metal nanowires, CNT and graphene are superior to the others.13-16 Moreover, since two-dimensional (2D) materials tend to attain lower contact resistance in constructing conductive networks when compared with one-dimensional (1D) materials, graphene is deemed as a superb conductive filler for CPNCs.17 Among the available graphene-contained CPNCs, however very few exhibit high conductivities in a range of 10-1000 S m-1, all of which are prepared via elaborate processes, e.g., selfassembly and templating, requiring high cost and facing scalability hurdles. 18,19 As for the mass-production methods, such as solution mixing and melt blending, the resulting graphene-contained CPNCs possess low conductivities of less than 0.1 S m-1 as a sharp contrast (Table S1). According to general effective media (GEM) conductivity model 20,21 and empirical evidence 22-24, several long-lasting pending challenges are as follows: i) poor dispersity of graphene due to its inertia and strong tendency to stacking;25 ii) low content of graphene that correlates with the dispersity. The more graphene is, the worse dispersity will be, which as a consequence causes a ceiling point of 3 wt%;26-28 and iii) random orientation of graphene that can be aligned merely under a small graphene content.29,30 For now, a widely accepted solution is to use graphene oxide (GO) instead of graphene. Due to GO’s abundant oxygen groups, GO-contained nanocomposites are handily prepared and GO is thereafter reduced, resulting in rGO-contained CPNCs.31-33 A relatively good dispersity and a high content up to 50 wt% have been reached for rGO.34 However, high loadings of rGO do not bring about a surge in conductivity as expected or even sometimes decrease (Table S1). The main reason is that the reduction of GO within composites is inevitably dampened.35,36 Therefore, there is a dilemma to be faced for either graphene or GO, which arouses a pressing need to develop a novel and facile method for graphene-contained CPNCs. Herein, two intriguing designs are proposed, i.e., use of slightly oxidized graphene sheets (SOGSs) and hot drawing of nanocomposites. Firstly, SOGSs are applied as a tradeoff between graphene and GO, which possess few oxygen groups and meantime



maintain an excellent conductivity. Due to the few oxygen groups, a high loading of 6.25 wt% and a mediocre dispersity for SOGSs are accomplished in poly(vinyl alcohol) (PVA) matrix by solution mixing, resulting in SOGS-PVA nanocomposites. Secondly, when hot drawing the nanocomposites, SOGSs are undergoing a rearrangement to obtain a largely improved dispersity and more importantly a high alignment. Consequently, a dense accordion-like SOGS network is produced in the final-state SOGS-PVA nanocomposites. The conductivity is as high as 25 S m-1, which is 8 and 2 orders of magnitude higher than those of PVA matrix and SOGS-PVA nanocomposites without hot drawing, respectively. Moreover, the proposed nanocomposites have huge potentials in flexible electronics, e.g., serving as heating films and flexible electrodes for supercapacitors. EXPERIMENTAL SECTION Poly(vinyl alcohol) (PVA, 2099) was purchased from Anhui Wanwei Group Co., Ltd. (China). Slightly oxidized graphene sheets (SOGSs) were kindly supplied by The Sixth Element Materials Technology Co., Ltd. (China). Graphene powders produced by mechanical exfoliation were supplied from Xiamen Knano Graphene Technology Co., Ltd. (China). Ammonium persulfate and pyrrole were bought from Sinopharm Chemical Reagent Co., Ltd. (China). As for the preparation of SOGS-PVA nanocomposites, firstly SOGSs were directly added into PVA aqueous solution under ultrasonic treatment at 0 ºC. Then a homogeneous SOGS/PVA dispersion was obtained. Secondly, SOGS-PVA nanocomposites were made via traditional casting method. Here weight contents of SOGSs in the nanocomposites were controlled in a range of 1 wt% to 6.25 wt%. Finally, the nanocomposites were drawn slowly at a speed of 0.5 mm s -1 at 120 ºC by a homemade translation stage. To deposit blends of polypyrrole (PPy) and SOGSs on the SOGS-PVA nanocomposite films, a deposition solution of 0.5 wt% SGOS and 1.5 wt% pyrrole monomer was firstly made by stirring at room temperature. Then the films were immersed into the deposition solution. Afterwards, 2 wt% ammonium persulfate aqueous solution was dropwise added to initiate the pyrrole polymerization, which lasted for 30 min. Finally, the deposited SOGS-PVA nanocomposite films were washed with ethanol and dried at 80 ºC. X-ray photoelectron spectroscopy (XPS, EscaLab 250Xi) and atomic force microscopy (AFM, bruker multimode7) were recorded on SOGSs. AFM samples were prepared by spinning coating SOGSs homogeneous dispersions on a mica surface. Morphologies of SOGS-PVA nanocomposites and graphene-PVA nanocomposites were measured by transmission electron microscopy (TEM, JEM-2100F). TEM samples were obtained by an ultramicrotome under cryogenic condition. Morphologies of PPy/SOGS-deposited


Page 4 of 20

Page 5 of 20 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


SOGS-PVA nanocomposite films were characterized by scanning electron microscopy (SEM, Hitachi S-4800 field emission). Fourier transform infrared spectroscopy (FTIR, Nicolet 6700) spectra were carried out on SOGS-PVA nanocomposites. Joule heating properties of SOGS-PVA nanocomposite films were recorded by infrared thermography (FLIR, A655sc). Sample sizes were 2 cm × 1.3 cm × 80 μm. Mechanical properties were studied by tension tester (Instron 5567) and dynamic mechanical analyzer (DMA, Q800, TA). The tensile speed was 5 mm min-1 and the gauge length was 20 mm. The test mode for DMA was 3-point bending with a frequency of 1Hz, a heating rate of 3 ºC min-1 and a temperature scanning range of 40 - 70 ºC. Conductivity tests of SOGS compacts were carried out by an equipment similar to that described in a published paper 37 and a load of 1 kN was applied. Resistances of SOGSPVA nanocomposites were measured by a high resistance meter (HRM, 6517B). Test conditions were relative humidity of 55% and room temperature of 25 ºC. Then volumetric conductivities were calculated using the following equation:  = L / (R ·S) Where L, R and S are the length, resistance and cross-sectional area of specimens, respectively. Electrochemical tests of PPy/SOGS-deposited SOGS-PVA nanocomposite films were performed using a three-electrode system on an electrochemical workstation (Chenhua, CHI660E). The PPy/SOGS-deposited SOGS-PVA nanocomposite films acted as the working electrode. Pt wire and Hg/Hg2SO4 electrode served as the counter and reference electrodes, respectively. And the electrolyte was 1M H2SO4 aqueous solution. The mass loading of PPy/SOGS was 0.8 mg cm-2. The capacitance was calculated from the galvanostatic charge/discharge curves, using the following equation: C = (2 × I × Δt) / ΔU where I, Δt and ΔU correspond to the discharge current, discharge time and voltage window, respectively. Gravimetric specific capacitances were calculated based on the weights of PPy/SOGS deposition layers. RESULTS AND DISCUSSION Figure 1a illustrates the scheme to the preparation of highly conductive SOGS-PVA nanocomposites. SOGSs possess a thickness of 1-1.5 nm (Fig. 1b) and a small oxygen content of 1.67 at% (Fig. S1). Conductivity of SOGS compacts is tested to be 3.6 ×103 S m-1. Compared with the theoretical value of 10.9 ×103 S m-1 for graphene compacts,37 SOGSs are demonstrated to own a high conductivity. To be mentioned, thanks to the remained high oxygen contents of 5 at% to 20 at% and defects of rGO38, the conductivity of rGO is much lower than SOGS.39,40 SOGSs are then mixed with PVA solution under ultrasonic treatment. Afterwards, SOGS-PVA nanocomposites are



readily prepared via conventional casting method with set SOGS loadings. The maximal SOGS content here is 6.25 wt%, beyond which it is difficult to disperse SOGSs in PVA matrix. In Figs. 1c, 1d and S2, SOGS contents are both of 6.25 wt%. Seen from Figs. 1c, S2a, S2b and S2c, the added SOGSs are aggregated into small clusters with a mediocre dispersity. To be mentioned, SOGSs exhibit much better dispersity than graphene sheets under same conditions due to SOGSs’ oxygen groups, which will be discussed in the sections below. Finally, a stunning rearrangement of SOGSs into an accordion-like network (Figs. 1d, S2d, S2e and S2f) is generated under hot drawing with a draw ratio of 2.5. To be mentioned, the conductivity anisotropy of SOGS-PVA nanocomposites after hot drawing is observed (Fig. S3), which verifies the alignment of SOGSs. Therefore, good dispersity, large loading and high alignment of SOGSs are achieved simultaneously, which definitely benefits the conductivity. Considering the elongation of nanocomposites, the maximal draw ratio is set as 2.5. Hereafter, SOGS(x)-PVA-y denotes the SOGS-PVA nanocomposite with x wt% SOGSs and underwent hot drawing with a ratio of y. Morphologies of SOGS-PVA nanocomposites with different SOGS contents and draw ratios are shown in Figs. S4 and S5. SOGS (1)-PVA-0, SOGS (3)-PVA-0 and SOGS(5)PVA-0 nanocomposites are shown in Figs. S4a, S4b and S4c, respectively. In all cases, SOGSs are prone to be agglomerated into clusters. And these clusters grow bigger with increasing the SOGS content, which means higher SOGS loadings lead to poorer SOGS dispersity. SOGS(5)-PVA-0, SOGS(5)-PVA-1.5 and SOGS(5)-PVA-2.5 nanocomposites are shown in Figs. S5a, S5b and S5c, respectively. It can be clearly learnt that a more aligned and uniform SOGS network is constructed with increasing the draw ratio. Conductivities of PVA and SOGS-PVA nanocomposites are tested at 25 ºC and relative humidity of 55%. PVA shows a low conductivity of 10-7 S m-1. And seen from Fig. 2a, conductivities of SOGS(1)-PVA-0, SOGS(3)-PVA-0, SOGS(3.8)-PVA-0, SOGS(5)PVA-0 and SOGS(6.25)-PVA-0 nanocomposites are 2 × 10-5, 1.1 × 10-4, 2.9 × 10-4, 0.026 and 0.074 S m-1, respectively. After hot drawing with a ratio of 2.5, they are correspondingly increased to 5.3 × 10-5, 0.088, 1.9, 6.4 and 25 S m-1, respectively. The increase multiple is in a range of 2.5-6550, which clarifies a high effectiveness of the hot drawing. As for nanocomposites without hot drawing, the percolation threshold of SOGSs is around 4 wt%, at which the effect of hot drawing is the highest. And for nanocomposites with hot drawing, the percolation threshold of SOGSs is advanced to about 2 wt%. Therefore, the hot drawing is vital for the construction of a conductive network, which is consistent with the observed morphologies.


Page 6 of 20

Page 7 of 20 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


Fig. 2b shows the influence of the draw ratio on conductivities of SOGS(6.25)-PVA nanocomposites. With increasing the draw ratio, a larger increase multiple is verified. This means a more aligned and uniform SOGS network is built by increasing the draw ratio abiding by the morphologies shown in Fig. S5. This same trend is observed in SOGS(1)-PVA nanocomposites (Fig. S6a) and SOGS (3.8)-PVA nanocomposites (Fig. S6b). However, the effect of the hot drawing is largely mitigated when the SOGS content is 1 wt%. A maximal conductivity reaches 25 S m-1 achieved by SOGS(6.25)PVA-2.5 nanocomposite, which is the best among the available graphene- and rGOcontained nanocomposites (Fig. 2c). Furthermore, even compared with carbon nanotube- and carbon black-contained CPNCs, the proposed SOGS(6.25)-PVA-2.5 nanocomposite is superior (Fig. S7). The high performance is benefited from the excellent conductivity of SOGSs and the dense accordion-like SOGS network. To have a distinct comparison, graphene-PVA nanocomposites are prepared using the same method. Nowadays, one consensus is that it is difficult to disperse graphene in polymer matrixes.41 Consequently, here a maximum of 3 wt% of graphene sheets are added into PVA matrix. Fig. S8 illustrates morphologies of graphene(1)-PVA-0 and graphene(3)-PVA-0 nanocomposites. Graphene sheets are found to be aggregated into compact clusters other than loose clusters for SOGSs (Fig. 1c). Therefore, graphene sheets have a much poorer dispersity than SOGSs. Fig. S9 shows morphologies of graphene(1)-PVA-2 and graphene(3)-PVA-2 nanocomposites. It is observed that graphene sheets are not rearranged by hot drawing. Conductivities of graphene(1)-PVA0, graphene(1)-PVA-2, graphene(3)-PVA-0 and graphene(3)-PVA-2 nanocomposites are tested as 1.3 × 10-7, 2.3 × 10-7, 3.4 × 10-7 and 3.9 × 10-7 S m-1, respectively. Poor conductivities are derived for graphene-PVA nanocomposites even though the conductivity of graphene sheets is better than that of SOGSs. A tremendous contrast is observed between graphene-PVA and SOGS-PVA nanocomposites. A non-uniform and non-aligned network of graphene is formed even though the content of graphene is no more than 3 wt%. The main difference between SOGSs and graphene sheets is whether or not having oxygen groups. Fourier transform infrared (FTIR) spectra of PVA and SOGS(6.25)PVA-0 nanocomposite are shown in Fig. 3a, which reveal typical bands of PVA and graphene. The peak around 3270 cm-1 is assigned to the symmetrical stretching vibration of hydroxyl groups, and the peak at 1080 cm-1 corresponds to the C-O stretching vibration.42 Moreover, the peak around 3270 cm-1 of PVA is shifted to a lower wavenumber after adding SOGSs. This manifests an interaction between PVA and SOGSs.43As for SOGSs, X-ray photoelectron spectroscopy (XPS) is conducted. Only C and O elements are observed. The C 1s core-level XPS spectra can be decomposed



by Gaussian curve fitting, which are shown in Fig. 3b. Peaks at 285.5 eV and 290.3 eV belong to C-O and O-C=O bonds, respectively.44,45 Therefore, the interaction is caused by the hydrogen bonding between hydroxyl groups of PVA and oxygen groups of SOGSs. Furthermore, this interaction is enhanced by the increase of SOGSs (Fig. 3c). Additionally, the interaction is further increased after hot drawing (Fig. 3c), which somehow verifies a more uniform dispersion of SOGSs in the hot-drawn nanocomposites. Oppositely, no interaction between PVA and graphene sheets is observed (Fig. S10). Therefore, it is the oxygen groups of SOGSs that help SOGSs disperse in PVA matrix and more importantly form an aligned and uniform network when undergoing hot drawing. Before application, the mechanical properties of SOGS-PVA-2.5 nanocomposites were studied. As seen from Fig. S11, the elongation is decreased with increasing the SOGS content. And SOGS(1)-PVA-2.5 possesses the highest yield strength. Although the SOGS(6.25)-PVA-2.5 nanocomposite has a much higher stiffness than PVA (Fig. S12), the SOGS(6.25)-PVA-2.5 film with a thickness of 80 μm can bear a small bending radius of 5 mm (Fig. S13). Moreover, the conductivity of SOGS(6.25)-PVA-2.5 film is very stable under bending with a radius of 5 mm (Fig. S14). The mechanical and conductive properties of SOGS(6.25)-PVA-2.5 nanocomposite render it promising in flexible electronics. Prototypes of flexible heating films made of SOGS(6.25)-PVA-2.5 nanocomposite are shown in Fig. 4. Here, films are 2 cm × 1.3 cm × 80 μm in dimensions. Joule heating properties are studied by tracing the temperature over the time (Fig. 4a). Owing to the high conductivity of SOGS(6.25)-PVA-2.5 nanocomposite, films are characterized by a fast response and a short time to reach the saturated temperature (about 10 seconds). Moreover, along with increasing input voltages from 10, 15 to 20 V, saturated temperatures rise from 37.2, 43.4 to 53.6 ºC. The thermal response of films is about 2 ºC s-1 at 20 V, which is comparable to some reported heating polymer-based films, e.g., 1.7 ºC s-1 at 7 V for Ag nanowire-PET composite46, 0.8 ºC s-1 at 12 V for graphene-PET composite47 and 3.7 ºC s-1 at 15 V for CNT-PET composite48. Here, PET denotes polyethylene terephthalate. Furthermore, the heating performance of films is well maintained under bending for 100 cycles with a bending radius of 1 cm (Fig. 4b). And since the good uniformity of nanocomposites, no dark points are found on the heated films (Fig. 4c). Another application of SOGS(6.25)-PVA-2.5 nanocomposite is serving as flexible electrodes for supercapacitors. Blends of polypyrrole (PPy) and SOGSs are deposited on the nanocomposite substrates as active materials. Here the weight ratio of PPy to SOGSs is 3:1. Cross-sectional morphologies of PPy/SOGS-deposited nanocomposites


Page 8 of 20

Page 9 of 20 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


are shown in Figs. 5a and 5b. The dash lines point out the interface between the PPy/SOGS deposition layer and the SOGS(6.25)-PVA-2.5 substrate. A well-bonded interface is demonstrated. And the thickness of PPy/SOGS deposition layer is about 10 μm. Top-view morphology of PPy/SOGS-deposited nanocomposites is shown in Fig. 5c, from which a porous structure of the deposition layer is observed. The arrows point the incorporated SOGSs. Afterwards, electrochemical properties are tested. Galvanostatic charge/discharge curves are shown in Fig. 5d, which are consistent with cyclic voltammetry curves (Fig. S15). Specific capacitances based on the active materials are calculated to be 291 and 230 F g-1 at 0.2 and 0.5 A g-1, respectively. To be noticed, there is no contribution of SOGS(6.25)-PVA-2.5 substrate to the capacitance. And the Coulombic efficiency for the first cycle is 90%, which can be larger than 95% just after several cycles. The values are superior to most of PPy-based films, e.g., 250 F g-1 for PPy/gold film49, 256 F g-1 for PPy/graphene film50 and 153 F g-1 for PPy/CNT film51. Moreover, capacitance retentions are 98% and 95% after 5000 cycles (Fig. 5e) and 100 bending cycles (Fig. 5f), respectively. Furthermore, electrochemical impedance spectroscopy (EIS) was used to analyze the electrodes. A small charge transfer resistance and a good capacitive behavior are demonstrated (Fig. S16).52 Therefore, a huge potential for the proposed SOGS-VPA nanocomposites in energy storage is testified. CONCLUSION Degree of oxidation of graphene is vital to the dispersion of graphene in polymer matrix and the consequent electrical properties of nanocomposites. Here, we control the degree of oxidation of graphene together with an operation of hot drawing nanocomposites to eventually achieve a uniform, dense and highly aligned graphene network in polymer matrix. Owing to this, an outstanding conductivity of 25 S m-1 is accomplished, which is the best among all of the graphene- and rGO-contained polymer nanocomposites via scalable solution mixing or melt blending. The discovery and the processing here shed a new light on conductive polymer nanocomposites. ASSOCIATED CONTENT Supporting Information The Supporting Information is available free of charge via the Internet at http://pubs.acs.org. Comparison on conductivity between this work and the available conductive polymer nanocomposites; XPS survey spectrum for SOGSs; TEM images of SOGS(1)-PVA-0, SOGS(3)-PVA-0 and SOGS(5)-PVA-0 nanocomposites, SOGS(5)-PVA-0, SOGS(5)PVA-1.5 and SOGS(5)-PVA-2.5 nanocomposites; Dependence of conductivity of SOGS-PVA nanocomposites on the draw ratio; Comparison on conductivity between SOGS(6.25)-PVA-2.5 nanocomposite and the graphene-, rGO-, CNT- and CB-



contained CPNCs; TEM images of graphene (1)-PVA-0 nanocomposites and graphene (3)-PVA-0 nanocomposites and the graphene (1)-PVA-2 and graphene(3)-PVA-2 nanocomposites; FTIR spectra for PVA and graphene(3)-PVA-0 nanocomposite (PDF) AUTHOR INFORMATION Corresponding Author E-mail: [email protected] (Wei Weng) E-mail: [email protected] (Meifang Zhu). Notes The authors declare no conflict of interest. ACKNOWLEDGMENTS This work was supported by Science and Technology Commission of Shanghai Municipality (16JC1400700), National Natural Science Foundation of China (51603038, 51673038), Program for Changjiang Scholars and Innovative Research Team in University (IRT16R13), and the Fundamental Research Funds for the Central Universities, DHU Distinguished Young Professor Program. REFERENCES (1) Nasim, A.; Ryon, S. S.; Ali, T.; Mario, M.; Afshar, B. M.; Alexander, A.; Pooria, M.; Jeong-Yun, S.; Suzanne, M.; Louis, C.; Xiaowu, T.; S., W. A.; Ali, K. Highly Elastic and Conductive Human-Based Protein Hybrid Hydrogels. Adv. Mater. 2016, 28, 40-49. (2) Wu, Y.; Wang, Z.; Liu, X.; Shen, X.; Zheng, Q.; Xue, Q.; Kim, J.-K. Ultralight Graphene Foam/Conductive Polymer Composites for Exceptional Electromagnetic Interference Shielding. ACS Appl. Mater. Inter. 2017, 9, 9059-9069. (3) Shahzad, F.; Alhabeb, M.; Hatter, C. B.; Anasori, B.; Man Hong, S.; Koo, C. M.; Gogotsi, Y. Electromagnetic Interference Shielding with 2D Transition Metal Carbides (MXenes). Science 2016, 353, 1137-1140. (4) Yu, C.; Hao B. Z.; Yanbing, Y.; Mu, W.; Anyuan, C.; Zhong-Zhen, Y. HighPerformance Epoxy Nanocomposites Reinforced with Three-Dimensional Carbon Nanotube Sponge for Electromagnetic Interference Shielding. Adv. Funct. Mater. 2016, 26, 447-455. (5) Zhang, H. B.; Zheng, W. G.; Yan, Q.; Yang, Y.; Wang, J. W.; Lu, Z. H.; Ji, G. Y.; Yu, Z. Z. Electrically Conductive Polyethylene Terephthalate/Graphene Nanocomposites Prepared by Melt Compounding. Polymer 2010, 51, 1191-1196. (6) Yousefi, N.; Sun, X.; Lin, X.; Shen, X.; Jia, J.; Zhang, B.; Tang, B.; Chan, M.; Kim, J.-K. Highly Aligned Graphene/Polymer Nanocomposites with Excellent Dielectric Properties for High-Performance Electromagnetic Interference Shielding. Adv. Mater. 2014, 26, 5480-5487. (7) Yu, M. m.; Chen, S. h.; Zhou, Z.; Zhu, M. F. Novel Flexible Broadband Microwave Absorptive Fabrics Coated with Graphite Nanosheets/Polyurethane Nanocomposites. Prog. Nat. Sci. 2012, 22, 288-294.


Page 10 of 20

Page 11 of 20 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


(8) Chun, K.Y.; Oh, Y.; Rho, J.; Ahn, J.-H.; Kim, Y. J.; Choi, H. R.; Baik, S. Highly Conductive, Printable and Stretchable Composite Films of Carbon Nanotubes and Silver. Nat. Nanotechnol. 2010, 5, 853-857. (9) Ke, K.; Pötschke, P.; Wiegand, N.; Krause, B.; Voit, B. Tuning the Network Structure in Poly(vinylidene fluoride)/Carbon Nanotube Nanocomposites Using Carbon Black: Toward Improvements of Conductivity and Piezoresistive Sensitivity. ACS Appl. Mater. Inter. 2016, 8, 14190-14199. (10) Zeng, Z.; Jin, H.; Chen, M.; Li, W.; Zhou, L.; Zhang, Z. Lightweight and Anisotropic Porous MWCNT/WPU Composites for Ultrahigh Performance Electromagnetic Interference Shielding. Adv. Funct. Mater. 2016, 26, 303-310. (11) Stankovich, S.; Dikin, D. A.; Dommett, G. H. B.; Kohlhaas, K. M.; Zimney, E. J.; Stach, E. A.; Piner, R. D.; Nguyen, S. T.; Ruoff, R. S. Graphene-based Composite Materials. Nature 2006, 442, 282-286. (12) Ajdari, F. B., Kowsari, E., Ehsani, A. Ternary nanocomposites of conductive polymer/functionalized GO/MOFs: Synthesis, Characterization and Electrochemical Performance as Effectiveelectrode Materials in Pseudocapacitors. J. Solid Sate Chem. 2018, 265, 155-166. (13) Mohammad, J.; David, D.; Valérie, M.; Gisèle, B. A Representative and Comprehensive Review of the Electrical and Thermal Properties of Polymer Composites with Carbon Nanotube and other Nanoparticle Fillers. Polym. Int. 2017, 66, 1237-1251. (14) Meng, F.; Lu, W.; Li, Q.; Byun, J.-H.; Oh, Y.; Chou, T.-W. Graphene-Based Fibers: A Review. Adv. Mater. 2015, 27, 5113-5131. (15) Sun, H.; You, X.; Deng, J.; Chen, X.; Yang, Z.; Ren, J.; Peng, H. Novel Graphene/Carbon Nanotube Composite Fibers for Efficient Wire-Shaped Miniature Energy Devices. Adv. Mater. 2014, 26, 2868-2873. (16) Kowsari, E., Ehsani, A., Dashti Najafi, M., Bigdeloo, M. Enhancement of Pseudocapacitance Performance of p-type Conductive Polymer in the Presence of Newly Synthesized Graphene Oxide-hexamethylene Tributylammonium Iodide Nanosheets. J. Colloid Interf. Sci. 2018, 512, 346-352. (17) Shi, E.; Li, H.; Yang, L.; Hou, J.; Li, Y.; Li, L.; Cao, A.; Fang, Y. Carbon Nanotube Network Embroidered Graphene Films for Monolithic All-Carbon Electronics. Adv. Mater. 2015, 27, 682-688. (18) Xia, G.; Tan, Y.; Chen, X.; Sun, D.; Guo, Z.; Liu, H.; Ouyang, L.; Zhu, M.; Yu, X. Monodisperse Magnesium Hydride Nanoparticles Uniformly Self-Assembled on Graphene. Adv. Mater. 2015, 27, 5981-5988. (19) Yang, W.; Hou, L.; Xu, X.; Li, Z.; Ma, X.; Yang, F.; Li, Y. Carbon Nitride Template-directed Fabrication of Nitrogen-rich Porous Graphene-like Carbon for High Performance Supercapacitors. Carbon 2018, 130, 325-332. (20) Zhao, W.; Kong, J.; Liu, H.; Zhuang, Q.; Gu, J.; Guo, Z. Ultra-high Thermally Conductive and Rapid Heat Responsive Poly(benzobisoxazole) Nanocomposites with Self-aligned Graphene. Nanoscale 2016, 8, 19984-19993. (21) He, H.; Li, X.; Wang, J.; Qiu, T.; Fang, Y.; Song, Q.; Luo, B.; Zhang, X.; Zhi, L. Reduced Graphene Oxide Nanoribbon Networks: A Novel Approach Towards Scalable



Fabrication of Transparent Conductive Films. Small 2013, 9, 820-824. (22) Huang, X.; Yin, Z.; Wu, S.; Qi, X.; He, Q.; Zhang, Q.; Yan, Q.; Boey, F.; Zhang, H. Graphene-Based Materials: Synthesis, Characterization, Properties, and Applications. Small 2011, 7, 1876-1902. (23) Yankowitz, M.; Watanabe, K.; Taniguchi, T.; San-Jose, P.; Leroy, B. J. Pressureinduced Commensurate Stacking of Graphene on Boron Nitride. Nat. Commun. 2016, 7, 13168. (24) Wang, N.; Tian, H.; Zhu, S.-Y.; Yan, D.-Y.; Mai, Y.-Y. Two-dimensional Nitrogen-doped Mesoporous Carbon/Graphene Nanocomposites from the Selfassembly of Block Copolymer Micelles in Solution. Chinese J. Polym. Sci. 2018, 36, 266-272. (25) Xu, Z.; Gao, C. Graphene Chiral Liquid Crystals and Macroscopic Assembled Fibres. nature 2011, 2, 571. (26) Zhang, Y.; Gong, S.; Zhang, Q.; Ming, P.; Wan, S.; Peng, J.; Jiang, L.; Cheng, Q. Graphene-based Artificial Nacre Nanocomposites. Chem. Soc. Rev. 2016, 45, 23782395. (27) Cai, D.; Song, M. Recent Advance in Functionalized Graphene/Polymer Nanocomposites. J. Mater. Chem. 2010, 20, 7906-7915. (28) Zhou, T.; Chen, F.; Tang, C.; Bai, H.; Zhang, Q.; Deng, H.; Fu, Q. The Preparation of High Performance and Conductive Poly (vinyl alcohol)/Graphene Nanocomposite via Reducing Graphite Oxide with Sodium Hydrosulfite. Compos. Sci. Technol. 2011, 71, 1266-1270. (29) Wang, D.; Zhang, X.; Zha, J.-W.; Zhao, J.; Dang, Z.-M.; Hu, G.-H. Dielectric Properties of Reduced Graphene Oxide/Polypropylene Composites with Ultralow Percolation Threshold. Polymer 2013, 54, 1916-1922. (30) Yousefi, N.; Lin, X.; Zheng, Q.; Shen, X.; Pothnis, J. R.; Jia, J.; Zussman, E.; Kim, J.-K. Simultaneous in situ reduction, Self-alignment and Covalent Bonding in Graphene Oxide/Epoxy Composites. Carbon 2013, 59, 406-417. (31) Wan, C.; Jiao, Y.; Li, J. Flexible, Highly Conductive, and Free-standing Reduced Graphene Oxide/Polypyrrole/Cellulose Hybrid Papers for Supercapacitor Electrodes. J.Mater. Chem. A 2017, 5, 3819-3831. (32) Zhao, X.; Zhang, Q.; Chen, D.; Lu, P. Enhanced Mechanical Properties of Graphene-Based Poly(vinyl alcohol) Composites. Macromolecules 2010, 43, 23572363. (33) Fu-Zhan, S.; Qi-Long, Z.; Xinchun, Y.; Wen-Wen, Z.; Pradip, P.; Nobuko, T.; Qiang, X. Metal-Organic Framework Templated Porous Carbon-Metal Oxide/Reduced Graphene Oxide as Superior Support of Bimetallic Nanoparticles for Efficient Hydrogen Generation from Formic Acid. Adv. Energy Mater. 2018, 8, 1701416. (34) Mo, S.; Peng, L.; Yuan, C.; Zhao, C.; Tang, W.; Ma, C.; Shen, J.; Yang, W.; Yu, Y.; Min, Y.; Epstein, A. J. Enhanced Properties of Poly(vinyl alcohol) Composite Films with Functionalized Graphene. RSC Adv. 2015, 5, 97738-97745. (35) Xu, Z.; Gao, C. Graphene Fiber: A New Trend in Carbon Fibers. Mater. Today 2015, 18, 480-492. (36) Guo, J.; Ren, L.; Wang, R.; Zhang, C.; Yang, Y.; Liu, T. Water Dispersible


Page 12 of 20

Page 13 of 20 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


Graphene Noncovalently Functionalized with Tryptophan and its Poly(vinyl alcohol) Nanocomposite. Compos. Part B-Eng. 2011, 42, 2130-2135. (37) Marinho, B.; Ghislandi, M.; Tkalya, E.; Koning, C. E.; de With, G. Electrical Conductivity of Compacts of Graphene, Multi-wall Carbon Nanotubes, Carbon Black, and Graphite Powder. Powder Technol. 2012, 221, 351-358. (38) Xu Y. P.; Xia X. L.; Dermot. D.; King. T. L. Synthesis of Electrochemicallyreduced Graphene Oxide Film with Controllable Size and Thickness and Its use in Supercapacitor. Carbon 2011, 49, 3488-3496. (39) Kian P. L.; Qiao L. B.; Goki E.; Manish C. Graphene Oxide as a Chemically Tunable Platform for Optical Applications. Nat. Chem. 2010, 2, 1015-1024. (40) Cristina G. N.; Jannik C. M.; Ravi S. S.; Andrey C.; Simon K.; Marko B.; Klaus K.; Ute K. Atomic Structure of Reduced Graphene Oxide. Nano Lett. 2010, 10, 11441148. (41) Monti, M.; Rallini, M.; Puglia, D.; Peponi, L.; Torre, L.; Kenny, J. M. Morphology and Electrical Properties of Graphene-epoxy Nanocomposites Obtained by Different Solvent Assisted Processing Methods. Compos. Part A-Appl. S. 2013, 46, 166-172. (42) Chen, S.; Ma, W.; Xiang, H.; Cheng, Y.; Yang, S.; Weng, W.; Zhu, M. Conductive, Tough, Hydrophilic Poly(vinyl alcohol)/Graphene Hybrid Fibers for Wearable Supercapacitors. J. Power Sources 2016, 319, 271-280. (43) Lim, M.-Y.; Shin, H.; Shin, D. M.; Lee, S.-S.; Lee, J.-C. Poly(vinyl alcohol) Nanocomposites Containing Reduced Graphene Oxide Coated with Tannic Acid for Humidity Sensor. Polymer 2016, 84, 89-98. (44) Zheng, S.; Li, Z.; Wu, Z.-S.; Dong, Y.; Zhou, F.; Wang, S.; Fu, Q.; Sun, C.; Guo, L.; Bao, X. High Packing Density Unidirectional Arrays of Vertically Aligned Graphene with Enhanced Areal Capacitance for High-Power Micro-Supercapacitors. ACS Nano 2017, 11, 4009-4016. (45) Cheng, Y.; Lu, H.; Zhang, K.; Yang, F.; Dai, W.; Liu, C.; Dong, H.; Zhang, X. Fabricating Pt-decorated Three Dimensional N-doped Carbon Porous Microspherical Cavity Catalyst for Advanced Oxygen Reduction Reaction. Carbon 2018, 128, 38-45. (46) TaeYoung, K.; Won, K. Y.; Seok, L. H.; Hyeongkeun, K.; Seok, Y. W.; S., S. K. Uniformly Interconnected Silver‐Nanowire Networks for Transparent Film Heaters. Adv. Funct. Mater. 2013, 23, 1250-1255. (47) Kang, J.; Kim, H.; Kim, K. S.; Lee, S.-K.; Bae, S.; Ahn, J.-H.; Kim, Y.-J.; Choi, J.-B.; Hong, B. H. High-Performance Graphene-Based Transparent Flexible Heaters. Nano Lett. 2011, 11, 5154-5158. (48) Kim, D.; Zhu, L.; Jeong, D.-J.; Chun, K.; Bang, Y.-Y.; Kim, S.-R.; Kim, J.-H.; Oh, S.-K. Transparent Flexible Feater Based on Hybrid of Carbon Nanotubes and Silver Nanowires. Carbon 2013, 63, 530-536. (49) Fanhui, M.; Yi, D., Sub-Micrometer-Thick All-Solid-State Supercapacitors with High Power and Energy Densities. Adv. Mater. 2011, 23, 4098-4102. (50) Zhu, J.; Xu, Y.; Wang, J.; Wang, J.; Bai, Y.; Du, X. Morphology Controllable Nano-sheet Polypyrrole-Graphene Composites for High-rate Supercapacitor. Phys. Chem. Chem. Phys. 2015, 17, 19885-19894.



(51) Lee, H.; Kim, H.; Cho, M. S.; Choi, J.; Lee, Y. Fabrication of Polypyrrole (PPy)/Carbon Nanotube (CNT) Composite Electrode on Ceramic Fabric for Supercapacitor Applications. Electrochim. Acta 2011, 56, 7460-7466. (52) Maryam N.; Lida F.; Ali E.; Saeed D. Facile Electrosynthesis of Nano Flower Like Metal-organic Framework and its Nanocomposite with Conjugated Polymer as a Novel and Hybrid Electrode Material for Highly Capacitive Pseudocapacitors. J. Colloid Interf. Sci. 2016, 484, 314-319.


Page 14 of 20

Page 15 of 20 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


Figure 1. Scheme to the preparation of highly conductive SOGS-PVA nanocomposites (a). AFM images of SOGSs (b). SEM images of SOGS(6.25)-PVA-0 (c) and SOGS(6.25)-PVA-2.5 (d) nanocomposites.



Figure 2. Dependence of conductivity of SOGS-PVA nanocomposites with and without hot drawing on the weight content of SOGSs (a). Dependence of conductivity of SOGS(6.25)-PVA nanocomposites on the draw ratio (b). Comparison on conductivity between SOGS(6.25)-PVA-2.5 nanocomposite and the available graphene- and rGOcontained CPNCs (c).


Page 16 of 20

Page 17 of 20 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


Figure 3. FTIR spectra for PVA and SOGS(6.25)-PVA-0 nanocomposite (a). XPS spectra of SOGSs (b). Enlarged FTIR spectra for PVA and several SOGS-PVA nanocomposites (c).



Figure 4. Joule heating characterization of the heating film made of SOGS(6.25)-PVA2.5 nanocomposite. Temperature–time curves at voltages of 10, 15 and 20 V (a). Retention of the saturated temperature at 20 V under bending for 100 cycles (b). Infrared images at 10, 15 and 20 V (c).


Page 18 of 20

Page 19 of 20 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


Figure 5. Morphologies and electrochemical properties of supercapacitor electrodes made of PPy/SOGS-deposited SOGS(6.25)-PVA-2.5 nanocomposite film. Crosssectional images with low (a) and high (b) magnifications. Top-view image (c). Galvanostatic charge/discharge curves (d). Long-life performance at 0.5 A g-1 (e). Capacitance retention for 100 bending cycles with a bending radius of 1 cm (f).



The Table of Contents


Page 20 of 20

Highly conductive nanocomposite enabled by an accordion-like

Recommend Documents