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The objective of this study was to prepare an electromagnetic interference shielding material, waterborne polyurethane (WPU) filled with silver-nanoparticle-decorated functional reduced graphene oxide (Ag@FRGO). Functional reduced graphene oxide (FRGO) was functionalized through free-radical polymerization before chemical reduction, to prevent restacking and aggregation during the reduction. After the functionalization, the homogeneous dispersion of FRGO promoted the formation of conductive networks throughout the WPU matrix. To enhance the electrical conductivity and electromagnetic interference shielding effectiveness (EMI SE) of the composites, silver nanoparticles (Ag NPs) were deposited on the FRGO surface. Subsequently, WPU composites were synthesized through the solution-mixing method. Their microstructure, morphology, electrical conductivity, and EMI SE were investigated, and the results showed that, among Ag@FRGO/WPU composites with different values for the weight ratio of Ag NPs to FRGO, the Ag@FRGO/WPU composite with 5 wt% FRGO and a weight ratio of Ag to NPs of 10:1 (10Ag@FRGO/WPU) exhibited the highest electrical conductivity (25.52 S/m) and an EMI SE of 35 dB in the frequency range of 8.2–12.4 GHz (X-band).

An approach for the preparation of silver nanoparticle-reduced graphene oxide/polyurethane composites (AgNP@RGO/PU) was proposed. An electrospinning process was utilized to fabricate a lightweight and flexible PU fiber mat. Graphene oxide (GO)/PU composites were prepared using a dip-coating method. Thus there happens a hydrogen bonding interactions between the GO sheets and PU fibers. A powerful reducing agent, hydriodic acid, was used to reduce GO/PU composites which transforms into RGO/PU composites. The composite exhibited low electrical resistance (3.5 × 10 2 Ω/sq) because of reduction reaction. Furthermore, AgNPs, which were modified with thiophenol, were deposited on the RGO/PU composite through π–π interactions between the aromatic functional groups on the AgNPs and the RGO by a dip-coating method. The obtained AgNP@RGO/PU composite exhibited a remarkably enhanced electrical property (

Nitrogen-doped reduced graphene oxide (N-rGO) has been synthesized using a simple, efficient method combining instant thermal exfoliation and covalent bond transformation from a melamine-graphene oxide mixture. The capacitive performance of N-rGO has been tested in both aqueous (0.5 M H 2 SO 4 ) and organic (1 M tetraethyl-ammonium tetrafluoroborate (TEABF 4 ) in propylene carbonate (PC)) electrolytes, which are compared with those obtained from thermal-reduced graphene oxide (T-rGO) and chemical-reduced graphene oxide (C-rGO). The contributions of scan-rate-independent (double-layer-like) and scan-rate-dependent (pseudo-capacitance-like) capacitance of all reduced graphene oxides in both aqueous and organic electrolytes were evaluated and compared. The results show that relatively rich oxygen-containing functional groups on C-rGO form significant ion-diffusion barrier, resulting in worse electrochemical responses in organic electrolyte. By contrast, the N-doped structures, large surface area, and lower density of oxygen-containing groups make N-rGO become a promising electrode material for organic electric double-layer capacitors (EDLCs). The capacitance rate-retention of N-rGO reaches 71.1% in 1 M TEABF 4 /PC electrolyte when the scan rate is elevated to 200 mVs −1 , demonstrating that N-rGO improves the relatively low-power drawback of EDLCs in organic electrolytes. The specific energy and power of a symmetric N-rGO cell in the organic electrolyte reach 25 Wh kg −1 and 10 kW kg −1 , respectively.

This study proposed a method to improve the mechanical properties and thermal conductivity of epoxy composites by incorporating multi-walled carbon nanotubes (MWCNTs) and multi-graphene platelets (MGPs) hybrid materials. The MWCNT can bridge adjacent MGPs and inhibit their aggregation effectively, leading to an increased contact surface area between MGP/MWCNT hybrid materials and epoxy matrix. From observing the fractured surface of composite by scanning electron microscope, MWCNT/MGP hybrid materials exhibited better compatibility than individual MWCNT and MGP did.The tensile strength of GD400-MWCNT/MGP/epoxy composites was 35.4% higher than that of epoxy, compared to only a 0.9% increase in tensile strength for MGP/epoxy composites. Thermal conductivity enhanced by 146.9% through incorporating MWCNT/MGP hybrid materials and 23.9% for MGP fillers, compared to non-derivatised epoxy.

Silver nanowire/reduced graphene oxide nanocomposites (AgNW/rGO) are synthesized using a two-step process: preparation of silver nanowire/graphene oxide (AgNW/GO) and the microwave-assisted hydrothermal (MAH) method. The nanocomposites are characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) analyses. Ascorbic acid (AA), dopamine (DA), and uric acid (UA) are determined simultaneously on the AgNW/rGO-modified screen-printed carbon electrodes (SPCEs) by cyclic voltammetry (CV) and linear sweep voltammetry (LSV). The results reveal that AgNW/rGO-modified SPCEs exhibit well-resolved oxidation peaks with a negative shift in peak potential and enhanced peak currents in the simultaneous determination of AA, DA and UA in comparison with the pure rGO-modified SPCEs, demonstrating the superior catalytic activity of AgNW/rGO composites. AgNW/rGO-modified SPCEs show the linear response of AA, DA and UA in the concentration range of 45–1550, 40–450 and 35–300 μM with a detection limit of 0.81, 0.26 and 0.30 μM (S/N = 3), respectively. The covalent bonds between AgNWs and rGOs are expected to suppress the random attachment of AgNWs and facilitate the electron transfer and reactant transport by constructing a porous and continuous electrically conductive network. The excellent sensitivity of AgNW/rGO composites makes them become promising electrode materials in the field of electrochemical biosensors.

Polypyrrole (PPy) has been polymerized onto reduced graphene oxide/carbon nanotube (rGO/CNT) to form an rGO/CNT/PPy composite using the chemical oxidation method. The electrochemical characteristics of the above composite in various aqueous electrolytes are systematically compared for the asymmetric supercapacitor application. The electrochemical characteristics of rGO/CNT/PPy in the electrolytes containing K + show improved reversibility and higher stability. Introducing XC-72 in preparing the electrode has been found to enhance the specific capacitance and the cycle stability of rGO/CNT/PPy. The charge storage stability of rGO/CNT/PPy + XC-72 in various potential windows has been evaluated through the potential bias stress test. An asymmetric supercapacitor (ASC) with a positive electrode of Mn 3 O 4 and a negative electrode of rGO/CNT/PPy + XC-72 is successfully demonstrated, which shows specific energy and power of 14. Wh kg −1 and 6.62 kW kg −1 with a cell voltage of 1.6 V. This ASC with a cell voltage of 1.6 V shows excellent charge–discharge cycle stability and ideal capacitive behavior in NaNO 3 even after the application of 3250 charge–discharge cycles.

An effective method is proposed to prepare octa(aminophenyl) silsesquioxane (OAPS) functionalized graphene oxide (GO) reinforced polyimide (PI) composites with a low dielectric constant and ultrastrong mechanical properties. The amine-functionalized surface of OAPS-GO is a versatile starting platform for in situ polymerization, which promotes the uniform dispersion of OAPS-GO in the PI matrix. Compared with GO/PI composites, the strong interfacial interaction between OAPS-GO and the PI matrix through covalent bonds facilitates a load transfer from the PI matrix to the OAPS-GO. The OAPS-GO/PI composite film with 3.0 wt % OAPS-GO exhibited an 11.2-fold increase in tensile strength, and a 10.4-fold enhancement in tensile modulus compared with neat PI. The dielectric constant (D(k)) decreased with the increasing content of 2D porous OAPS-GO, and a D(k) value of 1.9 was achieved.

A powerful synthesis strategy is proposed for fabricating porous polyaniline-reduced graphene oxide (PANI-RGO) composites with transparency up to 80% and thickness from 300 to 1000 nm for the counter electrode (CE) of bifacial dye-sensitizing solar cells (DSSCs). The first step is to combine the in-situ positive charge transformation of graphene oxide (GO) through aniline (ANI) prepolymerization and the electrostatic adsorption of ANI oligomer-GO to effectively control the thickness of ultrathin PANI-GO films by adjusting pH of the polymerization media. In the second step, PANI-GO films are reduced with hydroiodic acid to simultaneously enhance the apparent redox activity for the I3−/I− couple and their electronic conductivity. Incorporating the RGO increases the transparency of PANI and facilitates the light-harvesting from the rear side. A DSSC assembled with such a transparent PANI-RGO CE exhibits an excellent efficiency of 7.84%, comparable to 8.19% for a semi-transparent Pt-based DSSC. The high light-harvesting ability of PANI-RGO enhances the efficiency retention between rear- and front-illumination modes to 76.7%, compared with 69.1% for a PANI-based DSSC. The higher retention reduces the power-to-weight ratio and the total cost of bifacial DSSCs, which is also promising in other applications, such as windows, power generators, and panel screens.

Nanofiber fabric is firstly introduced to replace common microfiber fabrics as the platform for flexible supercapacitors. Nanofiber and microfiber electrodes can be simply fabricated using a dipping process that impregnates reduced graphene oxide (RGO) nanosheets into electrospun polyamide-66 (PA66) nanofiber and microfiber fabrics. RGO nanosheets are tailored to various sizes and only RGO with a medium diameter of 250–450 nm (denoted as M-RGO) can effectively penetrate the pores of nanofiber fabrics for constructing smooth conductive paths within PA66 nanofiber fabrics. The synergistic effect between suitable sizes of RGO nanosheets and nanofiber fabrics with a high specific area provides a symmetric supercapacitor composed of M-RGO/PA66 nanofiber fabric electrodes with high-volume and high-area specific capacitance ( C S,V and C S,A , equal to 38.79 F cm −3 and 0.931 F cm −2 at 0.5 A g −1 , respectively), which are much larger than that of a symmetric supercapacitor composed of RGO/PA66 microfiber fabric electrodes (8.52 F cm −3 and 0.213 F cm −2 at 0.5 A g −1 ). The effect of impregnating nanofiber fabrics with suitably sized RGO to promote C S,V and C S,A of flexible supercapacitors has been demonstrated.

This paper proposes an effective and simple approach to fabricate high-performance graphene oxide (GO)/soluble polyimide (SPI) composite films through a novel and effective process. In this method, GO is dispersed in a dissolved SPI (R-SPI) polymeric matrix with curing state, preventing the reduction of crosslinking reactions of the polymeric matrix, and resulting in substantial improvements in the mechanical and dielectric properties of the composite. The GO/R-SPI composite film contains only 1.0 wt% GO; it possesses high tensile strength (up to 288.6 MPa) and Young's modulus (7.58 GPa), which represent an increase of 260% in tensile strength and 402% in Young's modulus, compared with the neat SPI film (80.3 MPa and 1.51 GPa, respectively). The dielectric constant (Dk) decreases with an increase in the GO content; the Dk of the GO/R-SPI composite film can be as low as 2.1 (compared with 2.8 for the neat SPI film). This novel fabricating method provides a path for developing high-performance GO/R-SPI composite materials as next-generation low-k dielectric materials.

This study proposes an effective approach for fabricating silane-functionalized TiO2 nanoparticle/silicone resin (SR) composites that exhibit high transparency, high refractive indexes (RIs), high UV aging resistance, and high moisture barrier. The surfaces of TiO2 nanoparticles (TMOS-m-TiO2) were modified by a sol–gel process using tetramethoxyl (octadecyl) silane (TMOS). The TMOS-m-TiO2 exhibited a significant improvement in compatibility with the SR matrix. The TMOS-m-TiO2/SR composite, containing 0.1 phr of TMOS-m-TiO2, maintained an optical transmittance above 80% in the visible wavelength region. The RI increased with the increase of TMOS-m-TiO2 content, and the RI of the 0.10 phr TMOS-m-TiO2/SR composite was 1.566 (the RI of the neat SR was 1.541). Furthermore, the water vapor transmission rate of 0.10 phr TMOS-m-TiO2/SR composite was 32.8% lower than that of neat SR. This approach can be applied for developing high-performance SR composite materials that can be used in various applications, particularly in light-emitting (LED) diode encapsulants.

We prepared flexible, lightweight, and high electromagnetic interference (EMI) shielding performance graphene nanosheet (GNS)/water-borne polyurethane (WPU) composites. WPU, with sulfonate functional groups, was used as the polymer matrix. By adsorbing the cationic surfactant (stearyl trimethyl ammonium chloride) on the surface of the GNSs (S-GNSs), restacking and aggregation of the GNSs have been efficiently suppressed, which also attracted sulfonate groups from the WPU matrix. Because of the favorable interfacial interactions arising from electrostatic attraction, the S-GNS exhibited good compatibility with the WPU matrix. Such a homogeneous dispersion contributed to the construction of an electrical conductive network. The S-GNS/WPU composite exhibited a low electrical conductivity percolation threshold and an outstanding enhanced electrical conductivity of approximately 5.1 S/m. A high EMI shielding effectiveness of approximately 32 dB was obtained by the WPU composites with contents of 5 vol.% (approximately 7.7 wt.%) S-GNSs.

A simple, low-cost method for fabricating nitrogen-doped graphene (NG) is demonstrated by combining the ultrafast thermal exfoliation and covalent transformation from the melamine (MA)–graphene oxide (GO) mixture. NGs prepared at 300, 600, and 900 °C were systematically characterized by X-ray photoelectron spectroscopy (XPS), in which pyridinic-N, pyrrolic-N and graphitic-N are the main nitrogen-doped structures in various ratios. These NGs possess large specific surface area and porous microstructures, confirmed by the N2 adsorption–desorption isotherms. The NG-modified screen-printed carbon electrodes (SPCEs) were fabricated to detect ascorbic acid (AA), dopamine (DA) and uric acid (UA) simultaneously by cyclic voltammetry (CV) and linear sweep voltammetry (LSV). Due to the large specific surface area, mesoporous structures and nitrogen-doped sites, these NGs show highly electrochemical sensitivity for AA, DA and UA. Notably, the pyrrolic-N structure makes the negative shift in the oxidation peak potential of these biomolecules, showing the better catalytic activity than pyridinic-N and graphitic-N structures. The large surface area of NGs provides more nitrogen-doped sites to oxidize bio-compounds and enhances the corresponding currents. The good sensitivity of NG-modified SPCEs makes them become effective sensors for determining AA, DA and UA simultaneously. The discrimination to peak potential and current among these NGs can be observed.

Silver nanowires (AgNWs), modified by cysteamine, with a high electrical conductivity can be combined with high surface area graphene nanosheets (GNs) to form AgNW–GN hybrid nanomaterials. These materials with – NH 3 + functional groups in an alkaline environment can be deposited on waterborne polyurethane surfaces with the attraction of sulfonate functional groups to prepare transparent conductive films with high transmittance and low surface electrical resistance. This self-assembly method provides highly controllable transmittance and surface electrical resistance. The AgNWs can inhibit GNs from restacking and aggregation after reduction from graphene oxide, increasing the electrical conductivity between the GN interlayers. The AgNW–GN hybrid nanomaterial films show a sheet resistance of 86 Ω/sq with 80% light transmittance, and the value of DC conductivity to optical conductivity ratio reaches 19.81.

A 3D graphene sheet–carbon nanotube (GS–CNT) structure with a good wetting property, high porosity, and large surface area is homogeneously deposited with active amorphous manganese oxide ( a -MnO x ) by potentiodynamic deposition. The flowery a -MnO x nanostructure with ultra-slender petals (ca. 5–8 nm) on the framework of hierarchically porous GS–CNT matrix not only enables nearly full utilization of a -MnO x but also retains sufficient conductivity and porosity for the high-rate charge–discharge application. The use of a -MnO x on the 3D GS–CNT material produces a specific capacitance of MnO x of 1200 F g −1 which is much-higher than that of a pure a -MnO x electrode ( C S,Mn = 233 F g −1 ). The specific energy and specific power of a -MnO x /GS–CNT are respectively as high as 46.2 Wh kg −1 and 33.2 kW kg −1 , revealing that our work conceptually provides a way to produce porous structures composed of graphene, carbon nanotubes, and various electroactive materials for high-performance energy storage devices.

This study fabricates amine (NH(2))-functionalized graphene oxide (GO)/polyimide(PI) composite films with high performance using in situ polymerization. Linear poly(oxyalkylene)amines with two different molecular weights 400 and 2000 (D400 and D2000) have been grafted onto the GO surfaces, forming two types of NH(2)-functionalized GO (D400-GO/D2000-GO). NH(2)-functionalized GO, especially D400-GO, demonstrated better reinforcing efficiency in mechanical and thermal properties. The observed property enhancement are due to large aspect ratio of GO sheets, the uniform dispersion of the GO within the PI matrix, and strong interfacial adhesion due to the chemical bonding between GO and the polymeric matrix. The Young's modulus of the composite films with 0.3 wt % D400-GO loading is 7.4 times greater than that of neat PI, and tensile strength is 240% higher than that of neat PI. Compared to neat PI, 0.3 wt % D400-GO/PI film exhibits approximately 23.96 °C increase in glass transition temperature (T(g)). The coefficient of thermal expansion below T(g) is significantly decreased from 102.6 μm/°C (neat PI) to 53.81 μm/°C (decreasing 48%) for the D400-GO/PI composites with low D400-GO content (0.1 wt %). This work not only provides a method to develop the GO-based polyimide composites with superior performances but also conceptually provides a chance to modulate the interfacial interaction between GO and the polymer through designing the chain length of grafting molecules on NH(2)-functionalized GO.

This study demonstrates that platinum–ruthenium (PtRu) nanoclusters decorated on a composite consisting of graphene sheets (GS) and carbon nanotubes (CNTs), denoted as PtRu/GS-CNT, show highly electrocatalytic activity for methanol oxidation with excellent carbon monoxide (CO) tolerance. Herein, restacking of individual GS is effectively inhibited by introducing one-dimensional CNTs to form a 3-D porous microstructure. From the SEM image, CNTs act as useful nanospacers for diminishing the face-to-face aggregation of GS. This 3-D porous structure exposes extensive surface area for evenly depositing PtRu nanoclusters and facilitates the electrolyte/reactant diffusion, leading to the highly catalytic performances of resultant materials. The voltammetric forward peak current density to the reverse peak current density for PtRu/GS-CNT ( I f / I b = 6.33) is much higher than that of commercial catalyst, PtRu/Vulcan XC-72 ( I f / I b = 1.33), revealing the synergistic effects between GS and CNT on enhancing electrochemical activities of PtRu nanoclusters for the methanol oxidation and the carbon monoxide (CO) tolerance. Therefore, the 3-D GS-CNT nanocomposite is a promising support material for dispersing noble metal catalysts in the fuel cell applications.

This study develops a powerful strategy for fabricating the nitrogen-doped graphene sheets with good crystallinity, high specific surface area, and high percentages of pyridinic/graphitic-nitrogen structures. Due to the specified N-doping structures and high specific surface area of 719 m2 g−1, our N-doped graphene sheets show an excellent electrocatalytic activity for the oxygen reduction reaction (ORR). Keywords: Nitrogen-doped graphene sheet, Electrocatalyst, Oxygen reduction reaction

A remarkable synergetic effect between the multi-graphene platelets (MGPs) and multi-walled carbon nanotubes (MWCNTs) in improving the mechanical properties and thermal conductivity of epoxy composites is demonstrated. Stacking of individual two-dimensional MGPs is effectively inhibited by introducing one-dimensional MWCNTs. Long and tortuous MWCNTs can bridge adjacent MGPs and inhibit their aggregation, resulting in a high contact area between the MGP/MWCNT structures and the polymer matrix. Scanning electron microscope images of the fracture surfaces of the epoxy matrix showed that MWCNT/MGP hybrid nanofillers exhibited higher solubility and better compatibility than individual MWCNTs and MGPs did. The tensile strength of GD400-MWCNT/MGP/epoxy composites was 35.4% higher than that of the epoxy alone, compared to only a 0.9% increase in tensile strength for MGP/epoxy composites over the epoxy compound. Thermal conductivity increased by 146.9% using GD400-MWCNT/MGP hybrid fillers and 23.9% for MGP fillers, compared to non-derivatised epoxy.

Stacking of individual graphene sheets (GS) is effectively inhibited by introducing one-dimensional carbon nanotubes (CNTs) to form a 3-D hierarchical structure which significantly enhances the electrochemical capacitive performances of GS-based composites. From SEM images, inserting proper quantity of CNTs as nanospacers can effectively impede the stacking of GS and enlarge the space between GS sheets, leading to obtain a highly porous nanostructure. The specific capacitance of GS-CNTs-9-1 (∼326.5 F g−1 at 20 mV s−1) is much higher than that of GS material (∼83 F g−1). Furthermore, the energy and power densities of GS-CNTs-9-1 are respectively as high as 21.74 Wh kg−1 and 78.29 kW kg−1, revealing that the hierarchical graphene-CNT architecture provides remarkable effects on enhancing the capacitive performance of GS-based composites. Therefore, the GS-CNT composites are promising carbon materials for supercapacitors.

Flexible and lightweight graphene nanosheet (GN)/waterborne polyurethane (WPU) composites which exhibit high electrical conductivity and electromagnetic shielding performance were prepared. Covalently modifying GNs with aminoethyl methacrylate (AEMA; AEMA-GNs) through free radical polymerization effectively inhibited the restacking and aggregation of the GNs because of the -NH3(+) functional groups grafted on the AEMA-GNs. Moreover, the AEMA-GNs exhibited high compatibility with a WPU matrix with grafted sulfonated functional groups because of the electrostatic attraction, which caused the AEMA-GNs to homogeneously disperse in the WPU matrix. This homogeneous distribution enabled the GNs to form electrically conductive networks. Furthermore, AEMA-GNs with different amounts of AEMA segments were introduced into the WPU matrix, and the effects of the surface chemistry of the GNs on the electrical conductivity and EMI shielding performance of composites were investigated. AEMA-GN/WPU composites with a GN loading of 5 vol % exhibited remarkable electrical conductivity (approximately 43.64 S/m) and EMI shielding effectiveness (38 dB) over the frequency of 8.2 to 12.4 GHz.

In this study, we developed a simple and powerful method to fabricate flexible and lightweight graphene-based composites that provide high electromagnetic interference (EMI) shielding performance. Electrospun waterborne polyurethane (WPU) that featured sulfonate functional groups was used as the polymer matrix, which was light and flexible. First, graphene oxide (GO)/WPU composites were prepared through layer-by-layer (L-b-L) assembly of two oppositely charged suspensions of GO, the cationic surfactant (didodecyldimethylammonium bromide, DDAB)-adsorbed GO and intrinsic negatively charged GO, depositing on the negatively charged WPU fibers. After the L-b-L assembly cycles, the GO bilayers wrapped the WPU fiber matrix completely and revealed fine connections guided by the electrospun WPU fibers. Then, we used hydroiodic acid (HI) to obtain highly reduced GO (r-GO)/WPU composites, which exhibited substantially enhanced electrical conductivity (approximately 16.8 S/m) and, moreover, showed a high EMI-shielding effectiveness (approximately 34 dB) over the frequency range from 8.2 to 12.4 GHz.

Multiwalled carbon nanotube (MWCNT)/carbon fiber (CF)/vinyl ester (VE) laminate composites have been fabricated in this study. Pristine MWCNTs were treated with acid solution, which formed numerous oxygen-containing functional groups onto their surface, resulting in COOH-MWCNTs. Thereafter, acrylic functional groups were grafted onto the COOH-MWCNTs to generate acryl-MWCNTs. Three types of MWCNTs (pristine MWCNTs, COOH-MWCNTs, and acryl-MWCNTs) were used to reinforce the CF/VE-based composites. The dispersion of MWCNTs in the VE matrix and the interfacial interaction between MWCNTs and the VE matrix were investigated. Thereafter, the individual reinforcement efficiencies of these MWCNTs are compared. The flexural strength of the MWCNT/CF/VE composite with 1.0 phr acryl-MWCNTs content is 29.8% greater than that of neat CF/VE composites, and the flexural modulus of the MWCNT/CF/VE composite is 9.9% higher than that of neat CF/VE composites. Compared with neat CF/VE composites, 1.0 phr acryl-MWCNT/CF/VE composites exhibit an approximately 19.9 °C increase in glass transition temperature (Tg). The coefficients of thermal expansion significantly decreased from 47.2 ppm/°C of the neat CF/VE composites to 35.6 ppm/°C of the acryl-MWCNTs/CF/VE composites with 1 phr acryl-MWCNT content. This study provides a method for developing acryl-MWCNT/CF/VE composites with good dispersion of MWCNTs in VE matrix and strong interfacial interaction between the MWCNTs and VE matrix for enhancing the stress transfer from VE matrix to CF reinforcement.

Yu-Jen Lu1,2,#, Hung-Wei Yang1,#, Sheng-Che Hung3, Chiung-Yin Huang2, Shin-Ming Li4, Chen-Chi M Ma4, Pin-Yuan Chen2, Hong-Chieh Tsai2, Kuo-Chen Wei2, Jyh-Ping Chen1 1Department of Chemical and Materials Engineering, Chang Gung University, Kwei-San, Taoyuan, Taiwan; 2Department of Neurosurgery, Chang Gung Memorial Hospital, Kwei-San, Taoyuan, Taiwan; 3Department of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan; 4Department of Chemical Engineering, National Tsing Hua University, Hsinchu, Taiwan#These authors contributed equally to this workBackground: 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU), a commercial chemotherapeutic drug for treating malignant brain tumors, has poor thermal stability and a short half-life. Immobilization of BCNU on a nanocarrier might increase the thermal stability of BCNU and extend its half-life.Methods: Nanosized graphene oxide (GO) could be modified by polyacrylic acid (PAA) to improve the aqueous solubility and increase the cell penetration efficacy of the nanocarrier. PAA–GO intended as a drug carrier for BCNU was prepared and characterized in this study. The size and thickness of PAA–GO was investigated by transmission electron microscopy and atomic force microscopy, and the presence of PAA functional groups was confirmed by electron spectroscopy for chemical analysis and thermogravimetric analysis. BCNU was conjugated to PAA–GO by covalent binding for specific killing of cancer cells, which could also enhance the thermal stability of the drug.Results: Single layer PAA–GO (about 1.9 nm) with a lateral width as small as 36 nm was successfully prepared. The optimum drug immobilization condition was by reacting 0.5 mg PAA–GO with 0.4 mg BCNU, and the drug-loading capacity and residual drug activity were 198 µg BCNU/mg PAA–GO and 70%, respectively. This nanocarrier significantly prolonged the half-life of bound BCNU from 19 to 43 hours compared with free drug and showed efficient intracellular uptake by GL261 cancer cells. The in vitro anticancer efficacy of PAA–GO–BCNU was demonstrated by a 30% increase in DNA interstrand cross-linking and a 77% decrease in the IC50 value toward GL261 compared with the same dosage of free drug.Conclusion: Nanosized PAA–GO serves as an efficient BCNU nanocarrier by covalent binding. This nanocarrier will be a promising new vehicle for an advanced drug delivery system in cancer therapy.Keywords: graphene oxide, BCNU, glioma cells, drug delivery, thermal stability

Uniform and high-quality graphene oxide thin films were prepared using a dip-coating approach and were reduced to highly electrically conductive graphene nanosheet (GN) transparent conductive films (TCFs) using hydriodic acid. Silver nanowires (AgNWs), which were modified using thiophenol and exhibited a high aspect ratio and high electrical conductivity, were deposited on the surfaces of the GN TCFs through π–π interactions between the aromatic functional groups on the AgNWs and GNs to form high-performance GN/AgNW TCFs. The GN/AgNW hybrid nanomaterial films exhibited a sheet resistance of 71 Ω □−1 and 85% light transmittance.