Graphene Polymer Research Articles

Effects of graphene polymer nano composite coating on corrosion resistance of Astm A106 carbon steel pipe

Wide application prospects of graphene in the corrosion protection coatings field are owing to its excellent mechanical properties, outstanding chemical stability, corrosion resistance, and high corrosion resistance. Anti-corrosion composite was prepared using multilayer graphene powder as a filler and epoxy resin in this work to investigate the effect of graphene compositions in the zinc-rich epoxy (ZRE) as the modified anti-corrosion coating for carbon steel pipe. Using SEM for morphology along with the electrochemical performance was associated with changed content composite coating of graphene and pure epoxy resin coating. The measurement for open-circuit potential (OCP), the potentiostat polarization curve (Tafel Plot), and the electrochemical impedance spectroscopy (EIS) of the coating were conducted in order to investigate the influence of additional of graphene on the basic properties and corrosion resistance. From the experimental results, the increasing content of graphene led by the increasing value of OCP as the test system was stable, also the coating of high content graphene sustained a moderately high OCP ability with the increase of immersion time. From the results in the industrial environment, 0.1wt% Graphene + 99.9wt% ZRE in a 240μm coating layer would be sufficient as the corrosion rate is 0.0087204mmpy and three times lower compare to 100wt% ZRE. In a nutshell, the addition of graphene improves the impenetrability of the composite coating.

A developed theoretical model for effective electrical conductivity and percolation behavior of polymer-graphene nanocomposites with various exfoliated filleted nanoplatelets

In this paper, based on developing an analytical model, the effective electrical conductivity and percolation behavior of exfoliated polymer graphene nanocomposites (PGNs) are investigated. The graphene layers are considered as filleted cuboids which are randomly distributed in the matrix. The effects of several parameters including physical properties of graphene, matrix, interphase region, and quantum tunneling effect on the effective electrical conductivity and percolation behavior of PGNs are investigated. Moreover, comparing our results with the results obtained for graphene disc and cuboid composites, the present model makes a better prediction of the electric behavior of the compound. Afterward, our results are compared with five different experimental data sets and satisfactory agreement were found.

Study of induced structural, optical and electrochemical properties of Poly(3-hexylthiophene) (P3HT), [6,6]-phenyl-C61-butyric-acid-methyl-ester (PCBM) and their blend as an effect of graphene doping

Composites of graphene with Poly(3-hexylthiophene) (P3HT), [6,6]-phenyl-C61-butyric-acid-methyl-ester (PCBM) and their blends have been prepared via a facile chemical mixing approach. Graphene has been synthesized using a liquid phase chemical exfoliation method and characterized using imaging, electronic and spectroscopic techniques. Morphological analysis depicts the multi-layered structure of prepared graphene having approximately 9 layers, as estimated from Raman spectroscopy and AFM measurements. The value of energy gap between HOMO and LUMO of the prepared graphene has been determined using UV–Visible absorption spectroscopy and CV measurement, and found to be in close proximity. Further, UV–Visible and Raman spectroscopy suggest the formation of some localized trapping sites in between the band gap region of P3HT/PCBM and P3HT-PCBM blends as an effect of graphene doping leading to change in refractive index and bandgap values. Moreover, CV results also favour decrease in energy gap in composites after graphene loading Thus present study supports the well-dispersion and non-agglomeration of graphene within these polymers proper charge transfer between graphene layer and polymer chain. The sort of transfer of charge carriers from P3HT to graphene to PCBM is also conferring through the Raman measurements in blended films. Such interaction may help in designing of optoelectronic device with optimized photovoltaic performance.

Light weight non-metallic lightning strike protection film for CFRP

To reduce the weight of state-of-the-art aeronautical lightning protection material, a non-metallic lightning strike protection film was prepared. The new film consisted of 2 functional layers, which were capable of dispersing lightning current and blocking heat propagation from lightning plasma, respectively. Graphene and conductive polymer veil were adopted as electrical conductivity modifier; expandable graphite was adopted as thermal insulator. By integrating these functions, the new film featured by light weight, good bonding strength and lightning protection effectiveness, the lightning damage depth reduced by 79 % and the residual compression strength was increased by 21 %. This paper proposed and verified that establishing synergistic system which respond to electrical and thermal induced lightning damage simultaneously could remarkably increase the lightning protection effectiveness of CFRP, the prospect of this new technique was also discussed.

WITHDRAWN: Developing 3D printable hybrid graphene and carbon fibre polymer nanocomposites for fused filament fabrication

Abstract Fused filament fabrication 3D printing is currently limited for its application in producing aerospace components because of the performance of current polymeric materials. During this research a novel method for 3D printing 5% carbon fibre and different quantities of graphene nanoplatelets of between 0.01 and 5% has been developed. These formulations have been used to reinforce Polyethylene terephthalate thermoplastic that has been subsequently 3D printed to form full sized aerospace wing components. This research demonstrates how the novel polymer blend has significantly improved electrically conductive and mechanical properties over that of the parent polymer, which was evaluated after 3D printing. These results confirm that the formulation developed during this research has the performance properties required for 3D printing of aerospace structures. It has been observed that the process through which the nanocomposite masterbatch is manufactured is highly sensitive to the processes used. This is particularly the case when creating multi-material nanocomposite formulations. The research demonstrates how traditional 3D printing technology can be used to fabricate a range of high-performance functional components.

Screen-printed carbon electrode (SPCE) modified by molecularly imprinted polymer (MIP) nanoparticles and graphene nanosheets for determination of sertraline antidepressant drug

In this paper, a novel molecularly imprinted polymer (MIP) electrochemical sensor for selective detection of an antidepressant drug, sertraline (STR) has been developed. The precipitation polymerization method in the presence of sertraline hydrochloride as template molecules was used for synthesize of MIP nanoparticles. The sensor was developed by embedding a very thin layer of the MIP/graphene suspension on the handmade screen-printed carbon electrodes (SPCEs). The K3 [Fe(CN)6]/K4[Fe(CN) 6] redox couple was used as a probe to characterize the sensor by using cyclic voltammetry & differential pulse voltammetry methods. The sertraline binding experiments indicated that the MIP/graphene modified SPCEs have higher adsorption ability than the non-imprinted polymer(NIP)/graphene modified SPCEs. Factors affecting the sensor response such as composition of MIP/graphene suspension, extraction pH, preconcentration time and stirring rate of sample solution were optimized. Under optimal conditions, the sensor exhibited good sensitivity (177.25 µA L µmol−1) for sertraline with a linear range of 5.0 × 10−9 to 7.5 × 10−7 M (R2 = 0.9971) and detection limit of 1.99 × 10−9 M. The sensor was successfully applied for the determination of sertraline in tablet and human serum samples with recovery values in the range of 97.98–101.33%.

Recent Trends and Developments in Graphene/Conducting Polymer Nanocomposites Chemiresistive Sensors.

The use of graphene and its derivatives with excellent characteristics such as good electrical and mechanical properties and large specific surface area has gained the attention of researchers. Recently, novel nanocomposite materials based on graphene and conducting polymers including polyaniline (PANi), polypyrrole (PPy), poly (3,4 ethyldioxythiophene) (PEDOT), polythiophene (PTh), and their derivatives have been widely used as active materials in gas sensing due to their unique electrical conductivity, redox property, and good operation at room temperature. Mixing these two materials exhibited better sensing performance compared to pure graphene and conductive polymers. This may be attributed to the large specific surface area of the nanocomposites, and also the synergistic effect between graphene and conducting polymers. A variety of graphene and conducting polymer nanocomposite preparation methods such as in situ polymerization, electropolymerization, solution mixing, self-assembly approach, etc. have been reported and utilization of these nanocomposites as sensing materials has been proven effective in improving the performance of gas sensors. Review of the recent research efforts and developments in the fabrication and application of graphene and conducting polymer nanocomposites for gas sensing is the aim of this review paper.

Polymer based nickel ferrite as dielectric composite for energy storage applications

Graphene oxide (GO) and polymer based nanocomposites are emerging as a new class of materials having potential for flexible electronic devices and modern day energy storage devices. The traits like high mechanical strength, non-corrosive nature, low weight, being cost-effective, flexible, thermal and electrically insulated have made polymer based nano architectures highly effective for utilizing in energy storage applications. In the present research, the variation in structure, morphology and dielectric response of polypyrrole (PPy) is investigated by adding the nickel ferrite (NiFe2O4) and GO in it. The nano-materials, PPy, NiFe2O4 and GO were prepared by pyrrole’s polymerization, sol‒gel auto-combustion method and modified Hummer’s method, respectively. The solution mixing method was carried out to form GO/NiFe2O4/PPy nanocomposites with different concentrations by slowly mixing the already equipped nanomaterials. X-ray diffraction technique was employed for phase identification of as-prepared nanocomposites. The surface study and elemental composition was examined via field emission scanning electron microscope and energy dispersive X-ray spectroscope, respectively. The dielectric response of these samples was probed using impedance analyzer that was found to be in good agreement with Maxwell-Wagner model and Koop’s Phenomenological theory. Effective contribution of different electro-active regions was investigated from Nyquist plots.

Graphene composites: from hype-time shadows into the light of novel opportunities

The history of research into graphene polymer composites is shortly discussed including the extremely high initial expectations and the reasons why present graphene polymer composites often do not even come close to such properties. Furthermore, the properties and possible applications of realistic graphene polymer composites and some personal viewpoints on the needs to make these a commercial success will be given as well.

The Effect of Graphene Oxide on Flame Retardancy of Polypropylene and Polystyrene

Abstract This study discusses how a graphene oxide (GO) has been developed to improve flame resistance, ignitability, and flame threats of polystyrene (PS) and polypropylene (PP). For reasons where high thermal stability alongside fire-resistant parts for vehicles or airships is essential, the manufacture of lightweight products appears to have promising outcomes. Cone calorimeter and limiting oxygen index experiments were used to measure heat and fire experiments of PS and PP nanocompounds. The incorporation of GO into PS and PP structures has reduced the heat release rate as measured through cone calorimeter. The characterization implied that without clear accumulations, the GO nanolayers were properly distributed throughout the PS structure, resulting in an outstanding upgrade of thermal strength and fire safety characteristics. During the ignition period, GO dispersal in PS and PP accelerated the ignition period and lowered the heat release rate. In addition, the incorporation of GOs reduced the PP’s combustion rate as a result of developing a carbon protective layer that acts as a heat and mass transfer barrier. However, during combustion experiments, nanocompounds PS/GO and PP/GO generate a thermal insulation intumescent that protects the sublayers of the polymer. The peak of the heat release rate was reduced by 23 % for PP/GO and 53 % for PS/GO under flaming circumstances. The maximum thermal release rate indicates a substantial reduction for PP/GO 2.0 weight percent of nanocomposite compared to pure PP. This research shows that even GO inclusion does not change the limiting oxygen index values, but the development of an intumescent char protects the polymer sublayers properly. This feature offers a distinctive modification strategy to enhance GO’s flame-resistant effectiveness. This research offers excellent insights into PP and PS nanocompounds’ ignitability behavior with the inclusion of GO filler. This study delivers an appropriate choice to evaluate the potential for fire safety using graphene in polymers and flame-retarded polymers.

Calculating the Electrical Conductivity of Graphene Nanoplatelet Polymer Composites by a Monte Carlo Method.

Electrical conductivity is one of several outstanding features of graphene–polymer nanocomposites, but calculations of this property require the intricate features of the underlying conduction processes to be accounted for. To this end, a novel Monte Carlo method was developed. We first established a randomly distributed graphene nanoplatelet (GNP) network. Then, based on the tunneling effect, the contact conductance between the GNPs was calculated. Coated surfaces (CSs) were next set up to calculate the current flow from the GNPs to the polymer. Using the equipotential approximation, the potentials of the GNPs and CSs met Kirchhoff’s current law, and, based on Laplace equation, the potential of the CSs was obtained from the potential of the GNP by the walk-on-spheres (WoS) method. As such, the potentials of all GNPs were obtained, and the electrical conductivity of the GNP polymer composites was calculated. The barrier heights, polymer conductivity, diameter and thickness of the GNP determining the electrical conductivity of composites were studied in this model. The calculated conductivity and percolation threshold were shown to agree with experimental data.

Bio‐interface behaviour of graphene and semiconducting SWCNT:C60blend based nano photodiode for subretinal implant

Hybrid interfaces between living cells and organic conjugated polymers play a pivotal role in bioelectronics medicine. Currently, conjugated polymers are widely utilised for optical stimulation of living cells and other bio-interface applications such as neural probes, cellular scaffolds and biosensors for drug release. In such a work, the authors fabricated and characterised the Nano Photodiode array device for the subretinal implant. However, the authors did not discuss in their report about the biocompatibility of this new device. In this work, the authors manifest that the quintessential graphene electrode and polymer blend of semiconducting single-wall carbon nanotube and C60 fullerene (S-SWCNT:C60) sustains its optoelectronic properties all through the various strides for neural preparation. Further, the studies show that these materials can provide a favourable environment for cell proliferation and a high degree of biocompatibility. PC-12 cells used as a valuable model to validate the biocompatibility were grown successfully onto the S-SWCNT:C60 active layer still preserving its optical and electrical properties. The improved electrical performance of nano photodiode made of graphene, S-SWCNT:C60 established in the previous studies and the excellent bio-interface performance of this nano photodiode shows that the nano photodiode array proposed by the authors is a strong candidate for subretinal implants.

Layer-by-Layer Motif Heteroarchitecturing of N,S-Codoped Reduced Graphene Oxide-Wrapped Ni/NiS Nanoparticles for the Electrochemical Oxidation of Water.

A new heterostructured material is synthesized with lamellar arrangements in nanoscale precision through an innovative synthetic approach. The self-assembled Ni-based cyano-bridged coordination polymer flakes (Ni-CP) and graphene oxide (GO) nanosheets with a layered morphology (Ni-CP/GO) are used as precursors for the synthesis of multicomponent hybrid materials. Annealing of Ni-CP/GO in nitrogen at 450 °C allows the formation of Ni3 C/rGO nanocomposites. Grinding Ni-CP/GO and thiourea and annealing under the same conditions produces N,S-codoped reduced GO-wrapped NiS2 flakes (NiS2 /NS-rGO). Interestingly, further heating up to 550 °C allows the phase transformation of NiS2 into NiS accompanied by the formation of a face-centered cubic (FCC-Ni) metal phase between NS-rGO layers (FCC-Ni-NiS/NS-rGO). Among all the materials, the resulting FCC-Ni-NiS/NS-rGO exhibits good electrocatalytic activity and stability toward the oxygen evolution reaction (OER) owing to the synergistic effect of multiphases, the well-designed alternating layered structures on the nanoscale with abundant active sites.

Direct Evidence of Graphene‐Induced Molecular Reorientation in Polymer Films

AbstractFor the first time, direct evidence of graphene‐induced molecular reorientation in polymer films using polarization modulated infrared reflection absorption spectroscopy (PM‐IRRAS) is presented. By creating favorable electrostatic interactions, graphene–polymer interfaces can be controlled by varying polymer and solvent composition. After transfer of unmodified graphene from copper onto a polymer substrate, polymer chain rearrangement relative to the orientation at the polymer‐copper interfaces is observed using PM‐IRRAS. Transfer success is characterized using both optical transmission measurements and Raman spectroscopy to quantify the transfer fidelity, that is, graphene coverage fraction. Taken together, oxygen‐containing poly(ethylene‐co‐vinyl acetate) shows more polymer chain rearrangement and better graphene coverage compared to oxygen‐free polyethylene. Polymer composition seems to dominate graphene–polymer interactions while solvent choice has a smaller effect on transfer quality. These results are the first direct measurement of this effect and point toward the possibility of engineering graphene–polymer interactions for specific applications.

Modeling the Influence of Structure Morphology on the Physical and Mechanical Properties of Nanocomposites Based on a Polymer Matrix and Graphene Oxide

The influence of morphological features of nanocomposites based on a polymer matrix and graphene oxide on the effective elastic and electrically conductive properties is studied. The concept of a representative volume element (RVE), the geometry of which is modeled explicitly using specified parameters, is used. A method for analyzing the specific conductivity of a RVE that is based on graph theory taking into account the quantum tunneling effect is proposed. The results of evaluating the influence of orientation and volume fraction of inclusions on the numerical values of the effective mechanical properties and electrical conductivity are obtained.

Electroanalytical characteristic of a novel biosensor designed with graphene–polymer-based quaternary and mesoporous nanomaterials

Here, we propose the novel fabrication of graphene–polymer (GP)-based quaternary nanocomposite and mesoporous (MS) nanomaterials sensor [ $$\hbox {NaLa}(\hbox {MoO}_{\mathrm {4}})_{\mathrm {2}}$$ -GO-PPy (NLMG-PPy), CuZnSnSe-GO-PPy (CZSG-PPy) and $$\hbox {In}_{\mathrm {2}}\hbox {O}_{\mathrm {3}}$$ -G- $$\hbox {SiO}_{\mathrm {2}}\,20{\%}$$ (IGS20)] to address ignored challenges for Escherichia coli bacteria recognition in polluted samples. Synthesized samples were characterized through X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDX), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, nitrogen adsorption–desorption isotherms, X-ray photoelectron spectroscopy (XPS) and diffuse reflectance spectroscopy (DRS). The sensor could recognize an individual E. coli cell in $$1\,\upmu \hbox {l}$$ sample volume within 50 s. Through a low identification point of an individual cell, the MS and GP sensor had an absolute scope of 1–100 CFU per $$\upmu \hbox {l}$$ volume of sample (i.e. $$10^{\mathrm {3}}$$ – $$10^{\mathrm {5}}\,\hbox {CFU ml}^{\mathrm {-1}})$$ . The high thickness of negative charge on the surface of E. coli cells actively regulates the concentration of dominant part charge carriers in the mesoporous and G-polymer monolayer, permitting an ongoing check of E. coli concentration in a known sample. Our biosensor is simple and low-cost with great selectivity and fast identification was effectively shown for E. coli detection.

Nonlinear \u201coddities\u201d at the percolation of 3D hierarchical graphene polymer nanocomposites

The nonlinear rheology of a novel 3D hierarchical graphene polymer nanocomposites was investigated in this study. Based on an isotactic polypropylene, the nanocomposites were prepared using simple melt mixing, which is an industrially relevant and scalable technique. The novel nanocomposites stand out as having an electrical percolation threshold (≈0.94 wt%) comparable to solution mixing graphene-based polymer nanocomposites. Their nonlinear flow behavior was investigated in oscillatory shear via Fourier-transform (FT) rheology and Chebyshev polynomial decomposition. It was shown that in addition to an increase in the magnitude of nonlinearities with filler concentration, the electrical percolation threshold corresponds to a unique nonlinear rheological signature. Thus, in dynamic strain sweep tests, the nonlinearities are dependent on the applied angular frequency, potentially detecting the emergence of a weakly connected network that is being disrupted by the flow. This is valid for both the third relative higher harmonic from Fourier-transform rheology, I3/1, as well as the third relative viscous, v3/1, Chebyshev coefficient. The angular frequency dependency comprised non-quadratic scaling in I3/1 with the applied strain amplitude and a sign change in v3/1. The development of the nonlinear signatures was monitored up to concentrations in the conductor region to reveal the influence of a more robust percolated network.

Novel dispersion analysis and selective quantification of particulate components in graphene nanoplatelets–polymer–polymer hybrid composites

AbstractUp until now, no standard procedure to analyze and quantify the dispersion of particles in the polymer matrix exists. From the conductive hybrid polymer–polymer–graphene nanoplatelets composites we developed, this article attempts to showcase methodologies to analyze and quantify particle with the use of scanning electron microscopy images and collection of the elemental maps of carbon, oxygen, and nitrogen by energy dispersive spectroscopy (EDS) analysis. Image analysis was performed on the resulting map to extract the area and location data of graphene particles by subtracting elemental maps. Shadowing or charging problem in the images acquired from EDS was overcome by the polished surface and analyzing a sample twice using a novel approach of 180° opposed. Merging the data from the two elemental maps, taken 180° opposed, can be an alternative to the use of polished samples. From these different dispersion analysis approaches, it was possible to quantify different particles and their effects on the properties of the composites.

Bio-Nanocomposite Hydrogel Based on Zinc Alginate/Graphene Oxide: Morphology, Structural Conformation, Thermal Behavior/Degradation, and Dielectric Properties.

Bio-nanocomposite hydrogels based on sodium alginate (SA) as polymer matrix and graphene oxide (GO) nanosheets with zinc as crosslinking agent were synthesized with the aim of incorporating the intrinsic properties of their constituents (bioactivity and antimicrobial activity). Thus, stable and highly interconnected networks were obtained from GO nanosheets dispersed in SA matrices through interactions with low amounts of zinc. The GO nanosheets were successfully incorporated into the alginate matrix in the form of a complex nano-network involving different interactions: Bonds between alginate chains induced by Zn ions (egg box structure), interactions between GO nanosheets through Zn ions and hydrogen bonds between alginate chains, and GO nanosheets. The molecular interactions and morphology were confirmed by Fourier-transform infrared spectroscopy and transmission electron microscopy. The composite’s structural organization showed enhanced thermal stability. The glass transition temperature shifted to a higher temperature due to the reduced mobility induced by additional crosslinking bonds after incorporating the GO nanosheets and Zn into the polymer matrix. Finally, the dielectric behavior revealed that charge carrier mobility was hampered by the compact structure of the nanonetwork, which reduced conductivity. The combined properties of these nanocomposite hydrogels make them attractive biomaterials in the field of regenerative medicine and wound care since both surface bioactivity and antibacterial behavior are two critical factors involved in the success of a biomaterial.

Self-Enhanced Carbonized Polymer Dots for Selective Visualization of Lysosomes and Real-Time Apoptosis Monitoring.

SummaryProtons are highly related to cell viability during physiological and pathological processes. Developing new probes to monitor the pH variation could be extremely helpful to understand the viability of cells and the cell death study. Carbonized polymer dots (CPDs) are superior biocompatible and have been widely applied in bioimaging field. Herein, a new type of extreme-pH suitable CPDs was prepared from citric acid and o-phenylenediamine (CA/oPD-CPDs). Due to the co-existence of hydrophilic and hydrophobic groups, CA/oPD-CPDs tend to aggregate in neutral condition with a dramatic decrease of fluorescence, but disperse well in both acidic and alkaline conditions with brighter emission. This specialty enables them to selectively illuminate lysosomes in cells. Moreover, CA/oPD-CPDs in the cytoplasm could serve as a sustained probe to record intracellular pH variation during apoptosis. Furthermore, CA/oPD-CPDs present a continuous fluorescence increase upon 2-h laser irradiation in living cells, underscoring this imaging system for long-term biological recording.