Functional Groups Of Graphene Oxide Research Articles

Development of multifunctional graphene-based nanocomposites with synergistic effects of chemical and physical interactions

In this work, two types of graphene-based polyamide 66 (PA66) nanocomposites were prepared by in-situ polymerization. The effect of the surface functional groups of graphene oxide (GO) and the chemically modified GO (GO-DDA) on the structure and the properties of the nanocomposites were investigated. The nanocomposites achieved excellent enhancement in the properties. Compared to PA66/GO nanocomposites, PA66/GO-DDA nanocomposite showed higher Young’s modulus, tensile strength and thermal decomposition temperature at all the filler content. For example, at the filler content of 0.3 wt%, PA66/GO-DDA nanocomposite exhibited 92 % increase in the Young’s modulus, while PA66/GO nanocomposite exhibited 42 % increase. The thermal decomposition temperature was improved from 357 °C to 388 °C and to 383 °C by the incorporation of only 0.5 wt% of GO-DDA and GO, respectively. These results indicate the synergy reinforcement effect brought by the chemical interactions and the physical interactions between PA66 and GO-DDA.

Fabrication of highly flexible, wearable, free-standing symmetric supercapacitors with high voltage operation enabled by hierarchical graphene/cerium oxide/polypyrrole hybrid films

Flexible, free-standing supercapacitors play a significant role in the development of future wearable energy storage devices. Herein, we successfully fabricated the highly flexible and free-standing graphene/cerium oxide/polypyrrole hybrid films by thermal reduction of graphene oxide (GO) followed by the sol–gel synthesis of CeO2 and then the addition of PPy. By regulating oxygen functional groups in GO, the electronic conductivity and electroactive sites of the hybrid films are significantly controlled, leading to enhanced energy storage capability. Finally, a symmetric flexible supercapacitor (FSC) device was developed using the prepared films as electrodes. Resulting, the integrated symmetric GO-400/CeO2/PPy FSC manifests excellent areal capacitance of 49.0 mF cm−2 at 1 mA cm−2, with a durability of 83.1 % over 10,000 cycles. Specifically, the FSC exhibited capacitance retention of 77.2 % after 10,000 cycles under bending state with exceptional rate ability. Meanwhile, an impressive energy density of 19.69 µW h cm−2 was attained at a power density of 0.85 mW cm−2. Evidently, the synergistic interactions between GO and PPy nanosheets, along with CeO2 favour the rapid electron movement of electrode material for next-generation wearable, portable electronics.

Enhancing Efficiency and Stability in Carbon-Based Perovskite Solar Cells by Double Passivation with Ultralow-Cost Coal-Derived Graphene and Its Derivatives.

Coal-derived carbon nanomaterials possess numerous superior features compared to other classic carbon, such as readily accessible surfaces, tunable pore structure, and facile and precise surface functionalization. Therefore, the controllable preparation of coal-derived carbon nanomaterials is anticipated to be of great significance for the performance improvement and commercialization process of carbon-based perovskite solar cells (C-PSCs). In this study, we successfully synthesized highly stable and commercially valuable graphene oxide (GO) and reduced graphene oxide (rGO) utilizing coal. Compared to traditional methods and commercial graphene, the chemical oxidation and pyrolysis process used in this study is mild and simple, offering the advantages of controlled composition and the absence of other impurities. GO or rGO was incorporated into the top of the SnO2 electron transport layer (ETL) of C-PSCs. Under optimized conditions and ultraviolet-ozone (UVO) irradiation, the ultimate power conversion efficiency (PCE) increased from the unmodified 12.4 to 14.04% (based on rGO) and 15.18% (based on GO), representing improvements of 22 and 31%, respectively. The improved photovoltaic performance is mainly owing to enhanced charge transport capabilities, denser interfacial contacts, improved carrier separation properties, increased conductivity, and abundance of hydrophilic functional groups in GO, which can form more stable hydrogen bonds with SnO2. After being stored at room temperature and ambient humidity for 30 days, the modified, unpacked devices retained 87% of the highest power conversion efficiency (PCE). This study introduces a practical and manageable method to enhance the performance of C-PSCs by using functional carbon nanomaterials derived from coal.

Calcium-facilitated adsorption and precipitation of bacteria on the graphene oxide surface

Efficient removal of bacteria from aqueous environments is a hot research topic. Graphene oxide (GO) has been widely used due to its antimicrobial properties and high surface activity. However, GO alone could not remove bacteria from the aqueous environment through aggregation and precipitation. In this study, CaCl2 (Ca2+) was introduced into the process of bacterial removal by GO due to the negative charge on the surface of the removed bacteria (Sporosarcina pasteurii). The introduction of Ca2+ leads to the re-accumulation of GO layers, and the proportion of oxygen-containing functional groups in GO increases significantly. AFM and zeta potential results indicate a reduction in the negative charge on the GO surface in the presence of Ca2+, which reduces the electrostatic repulsion to bacteria. This leads to a gradual increase in the attractiveness of the GO surface and the adsorption of more bacteria. Ca2+ acts as a bridge, facilitating the sedimentation of GO and bacteria, resulting in the removal of bacteria from the water environment. The removal efficiency of GO against bacteria increased as the concentration of Ca2+ increased.

Triggering triboelectric nanogenerator antibacterial Activities: Effect of charge polarity and host material correlation

Triboelectric nanogenerators (TENGs) offer promising motion-driven energy harvesting for human–machine interactions, particularly in wearable healthcare and biomedical devices. However, direct skin contact demands addressing aggressive bacterial growth risks. The “triangle” interaction between bacteria, electrical stimulation, and host materials has been investigated comprehensively in the present study to facilitate appropriate self-antibacterial designs for TENGs. In so doing, it was revealed that the growth of negatively charged bacterial models (Escherichia coli and Staphylococcus aureus) was inhibited by induced positively charged substrates (Al or graphene oxide (GO)), regardless of the host material's composition due to the direct electrostatic interactions. Electron capture from the bacterial respiratory chain by the substrates leads to the interruption of the bacterial energy supply. In response to negative charges, however, an appreciable host-dependent antibacterial behaviour was observed, with Al showing a negligible bactericidal effect, while GO exhibited robust antibacterial properties. This effect was assigned to reactive oxygen species (ROS) generation, triggered by shuttling the negative charges to the oxygen functional groups in GO, suppressing bacterial growth efficaciously. The observed correlation between the electrostatic charge polarity and the material composition of the substrates (hosting the bacteria) highlights the superiority of ROS induction in the antibacterial properties of TENG. These findings pave the way for developing innovative approaches to control bacterial growth effectively and enhance the applicability of TENGs as advanced wearable devices with inherent antibacterial capabilities.

Fabrication optimization of polyethersulfone adsorptive mixed matrix membrane for enhanced dynamic methylene blue removal: Response surface methodology approach

AbstractIn the present study, the polyethersulfone (PES)/graphene oxide (GO)/polyethylene glycol 200 (PEG‐200) adsorptive mixed matrix membranes (AMMMs) were fabricated using a non‐solvent induced phase inversion method. According to the design of experiments using response surface methodology (RSM), PES concentration (15, 17.5, and 20%), PEG‐200 concentration as a pore former additive (0.5, 2.5, and 4.5%), and GO nanosheet loading percent (0, 0.5, and 1%) were varied during fabrication. A green solvent, dimethyl sulfoxide, was used as an alternative to conventional solvents, while it exhibited better membrane performance. Methylene blue (MB) removal was optimized in PES AMMM synthesis using RSM. Attenuated total reflectance Fourier transform infrared spectroscope confirmed the presence of GO functional groups in the optimum membrane. Scanning electron microscopy analysis revealed the optimum membrane was thicker than the neat membrane and atomic force microscopy analysis demonstrated higher surface roughness. The membranes hydrophilicity increased, with a decrease in water contact angle from 61.1 ± 0.2° (neat PES) to 54.4 ± 0.9° (optimal membrane). Pure water flux of 524.8 L m−2 h−1 and MB rejection of 97.46% were obtained for the optimum membrane. Furthermore, the optimum PES AMMM demonstrated a greater dynamic adsorption capacity in comparison to the unmodified PES membrane.Highlights The optimization of the polyethersulfone (PES) adsorptive mixed matrix membranes (AMMM) for methylene blue removal was performed utilizing the response surface methodology. The calculation of the dynamic adsorption capacity (DAC) was performed through the breakthrough curves. The integration of graphene oxide into the AMMM resulted in an enhanced DAC of the AMMM. The PES AMMM performance is based on Donnan electrostatic exclusion.

Optimizing the micro/mesoporous structure of hierarchical graphene aerogel for CO2 capture by controlling the oxygen functional groups of graphene oxide

BackgroundGraphene aerogels as solid porous adsorbents are great candidates for CO2 adsorption based on their tunable hierarchical pore structure and oxygenated groups on graphene oxide can control the self-assembly and pore structure of graphene aerogels. MethodsModified Hummer's method was used to synthesize graphene oxides by using various levels of H2SO4, KMnO4, and H2O2 and 3D graphene aerogels were synthesized via the hydrothermal and freeze-drying method. FTIR, RAMAN, XRD, FE-SEM, and BET analysis were used for characterizations. Significance findingsThe effect of graphite oxidation conditions on the hierarchical porous structure of graphene aerogel for CO2 adsorption was investigated. The graphene aerogel with the high meso and micro surface areas and the highest Sm/ST value (micro surface area/total micro and meso surface area) of 33% and also, the adequate macropores was achieved using high dosage of H2SO4 in the graphene oxidation process led to the highest CO2 adsorption capacity of 1.72 mmol/g. increasing the H2O2 dosages increased the macropores in the aerogel structure and improved the value of Sm/ST leading to an increase in the CO2 adsorption capacity. The high content of KMnO4 led to low Sm/ST value and fewer macropores and decreased the CO2 adsorption capacity (1.04 mmol/g).

Role of oxygen functional groups and attachment of Au nanoparticles on graphene oxide sheets for improved photodetection performance.

Integrating low-dimensional graphene oxide (GO) with conventional Si technology offers innovative strategies for developing ultrafast wideband photodetectors. In this study, we synthesized GO and explored its potential application in broadband photodetection alongside silicon heterostructures. The as-synthesized GO contains various oxygen functional groups, as evidenced by X-ray photoelectron and Fourier transform infrared spectroscopy. These functional groups contribute to increased photo absorption, enhancing photodetection performance. The systematic reduction of these functional groups from the GO surface via thermal annealing decreases photo absorption and consequently lowers the photocurrent. This reduction diminishes photo absorption and amplifies the dark current by approximately 25 times, from 20 nA to 496 nA. This dark current increase is attributed to the electron mobility following the reduction of functional groups. However, attaching plasmonic gold nanoparticles (Au NPs) to the GO surface enhances UV-Vis absorption in the visible region, enabling broadband detection. The even distribution of attached Au NPs on the GO surface is confirmed through field emission transmission electron microscopy. While thermal annealing of GO diminishes the responsivity from 4.6 A W-1 to 3.0 A W-1, the attachment of Au NPs augments the responsivity by more than two-fold, reaching 10.0 A W-1. Thus, it highlights the importance of rich oxygen functional groups in GO and the attachment of Au NPs to achieve more efficient photo-sensing properties.

Investigating the Antibacterial Activities of Graphene Oxide Loaded Spiky Gold Nanocomposites via Chitosan linker

The graphene oxide (GO) loaded spiky gold (AuNS) nanocomposites were prepared by electrostatic interaction between negatively-charged GO nanosheets and positively-charged AuNS by the assistance of chitosan as linker molecules. The AuNS/GO nanocomposites exhibit a red-shift in the extinction spectra and a reduction in the zeta potential compared to those of the pristine AuNS due to the presence of oxygen-containing functional groups in GO. The bactericidal analysis demonstrates that the incorporation of GO greatly enhances the intrinsic antibacterial activities of AuNS. Besides, the AuNS with smaller size exhibit better bactericidal efficiency compared to that of AuNS with bigger size. Upon light irradiation, the AuNS/GO with the absorption peak close to the wavelength of excitation light (900 vs. 904 nm) demonstrates a noticeable improvement in the bactericidal efficiency which is attributed to the plasmon-induced photothermal effect. All these results suggest that the AuNS/GO nanocomposites can work as a promising functional material for both intrinsic and plasmon-induced antibacterial materials.

The Effect of Magnetic Stirring Duration and Ascorbic Acid Concentration on the Yield of Reduced Graphene Oxide Isolated from East Kalimantan Bituminous Coal

East Kalimantan bituminous coal has a carbon composition of 70.24%, indicating a crystal structure of graphite layers. This makes it a viable material for creating reduced graphene oxide (r-GO), which has multiple advantages in various properties and can be employed in numerous technological applications. RGO is obtained by nearly eliminating oxygen functional groups in graphene oxide (GO) through sonication for 3 hours at pH 4. The yield with the lowest value at a 30% concentration of ascorbic acid and 50 minutes of magnetic stirring was selected as optimal. To characterize the resulting product, FTIR was utilized and revealed that O-H (84.21%), C=C (63.04%), and C-O-C (61%) had the highest %T. Technical abbreviations were explained upon first use. Energy-dispersive X-ray (EDX) analysis demonstrated a 90.6% increase in carbon content from 40.159% in GO to 76.554% in r-GO. In parallel, oxygen content decreased from 40,973% in GO to 17.551% in rGO, marking a 57.16% decrease. The morphology of the resulting rGO closely resembled the reference. Additionally, rGO exhibited a C:O ratio of 4.378, surpassing the C:O ratio of GO, which was 1.02. RGO density and pH value were 1.45 g/cm3 and 2, respectively.

Sulfonic acid (-HSO3) functionalization effect on graphene oxide membrane by (3 mercaptopropyl) trimethoxysilane and their applications in hydrogen membrane fuel cells

Conventional proton exchange membrane fuel cells (PEMFCs) use a perfluorinated ionomer membrane, e.g., Nafion®, which is expensive and subject to a rigorous synthesis process. Graphene oxide membrane (GOM) is acknowledged as a promising alternative electrolyte due to its hydrophilic nature and attractive proton conductivity in wet conditions. However, GOM loses its negative surface functional groups by hydrogen gas at the anode during operation in PEMFCs, resulting in increased electronic conductivity. In addition, two-dimensional graphene oxide (GO) nanosheets exhibited a larger anisotropy difference in proton conductivity compared to Nafion®. In this study, (3-mercaptopropyl)trimethoxysilane (MPTS, HS(CH2)3Si(OCH3)3) was reacted with the surface of GO nanosheet (M-GOM) by vigorous stirring, where unreacted MPTS was partially removed by a rinsing cycle except the M-GOM powder. Reactive MPTS has two essential reactions which were carried out by forming a hydrolysis reaction (Si-OCH3 to Si-OH) and a condensation reaction (Si-OH to Si-O-Si). The thiol groups of MPTS were oxidized to sulfonic acid groups (-HSO3) to provide high proton conducting stations with GO functional groups (M-GOM/oxid) and compared with non-oxidized thiol groups in a GO matrix (M-GOM/unoxid). The superior –HSO3 effect on M-GOM have reported for proton conductivity, physicochemical properties, ion exchange capacity, thermal stability, gas permeability and fuel cell performance. Furthermore, a hydrogen-permeable metal layer was deposited by a DC magnetron sputter to increase mechanical strength and reduce fuel crossover. A dual-layer membrane composed of M-GOM/unoxid or M-GOM/oxid and Pd thin film was analyzed as an electrolyte for a hydrogen membrane fuel cell (HMFC), which simultaneously performs two roles, an anode catalyst and an electrolyte.

Improving the interfacial properties of PVA fiber and cementitious composite: Design and characterization

Poly vinyl alcohol (PVA) fiber has been widely applied to improve the ductility of cementitious materials, and the overall performance of fiber reinforced cementitious materials largely depends on the interfacial properties of the fiber and cementitious matrix. In this work, a novel design of graphene oxide (GO) modified PVA fiber is proposed to improve the interfacial properties of PVA fiber and cementitious matrix. It is found that the interaction between GO and PVA fiber forms the hydrogen bond and enables the GO to form a tight three-dimensional bonding on the surface of the PVA fiber. Meanwhile, the oxygen-containing functional groups of GO could form chemical bond with the hydration products and promote the formation of denser microstructure at the interface. Therefore, the introduction of GO prominently improves the interfacial properties of PVA fiber and cementitious matrix, which is verified by the characterizations on the microstructures and morphologies. Furthermore, it is found that GO remarkedly improves the interfacial mechanical properties and results that a zone with the enhanced mechanical properties appears near the interface, verified by the characterizations on the micro-mechanical properties including fracture toughness near the interface.

High-efficiency recyclable reduced graphene oxide-tin oxide nanocomposite catalyst for esterification

Graphene oxide (GO) possesses 2D nanostructures and was synthesized indigenously via the enhanced Hummer method. It is well-accepted that the redox approach is a distinctive technique to fabricate GO on an expanded scale. Here, reduced graphene oxide-tin oxide (SnO2-rGO) nanocomposite material was produced for application as an efficient heterogeneous solid acid catalyst esterification reaction. Fourier transform infrared analysis was carried out to validate the incidence of oxygen functional groups in GO and SnO2-rGO nanocomposite. The Raman spectra of GO and SnO2-rGO nanocomposite have been simulated to get stable structure and functional groups. To get surface morphological and structural features, powder X-ray diffraction, scanning electron microscope-energy dispersive X-ray spectra, transmission electron microscope and high resolution-TEM analysis, and thermogravimetric analysis were delineated during this experimental study. It is seen that the catalyst has high efficiency for esterification reaction. The maximum efficiency (96% yield) was obtained when a 1:3 (acetic acid to benzyl alcohol) molar ratio, catalyst (25 mg), temperature (60 0C), and time (4 h) were maintained. The SnO2-rGO nanocomposite was recycled several times with a minimal loss of its efficiency.

Analysis of Microwave Absorption Properties of Graphene Oxide from Rice Husk Waste

Graphene Oxide (GO) was synthesized with variations in carbonization temperatures of 250 °C, 300 °C, and 350 °C using the modified Hummers method. The results of the synthesis of GO will then be tested for microwave absorbing properties because it can be applied in various fields, such as information technology, medical equipment, industry, polymer synthesis, and organic synthesis. Therefore, in this report, GO uses rice husk waste instead of graphite as a carbon source because rice husk waste is abundant in nature and easy to obtain than graphite. In addition to reducing waste in Indonesia, this study aimed to determine the crystal size and GO functional groups and analyze the properties of microwave absorbers. X-ray diffraction (XRD) was used to determine the crystal size. The GO functional groups were determined using Fourier Transform Infrared (FTIR), and the microwave absorption characteristics of GO were analyzed using a Vector Network Analyzer (VNA). The XRD results show GO peaks between 26° peaks and 44° peaks. In the FTIR results, there are a collection of GO practices, in particular CO, C = C, and C = O. In the VNA results, the best microwave absorption properties are at an ignition temperature of 350 °C with the lowest reflection value - 39.95 dB, the highest absorption coefficient is 99%, and the absorption bandwidth is 0.06 GHz at a frequency of 8.5 GHz

Mechanical properties and micromechanics of graphene oxide modified calcareous sand-cement mortar

In the engineering context of island blowing and reclamation, the modification effect of graphene oxide on the mechanical properties of calcareous sand cement mortar is analyzed, and the modification mechanism is elaborated from the microscopic perspective. The experimental results show that graphene oxide promotes the hydration reaction of calcareous sand-cement mortar, and the amount of graphene oxide doping significantly affects the modification effect. The modification effect gradually enhances when the graphene oxide doping amount increases from 0 to 0.06%, and the unconfined compressive strength of the specimens increases up to 36.96%. However, the modification effect decreases when the doping amount is 0.1% compared with that of 0.06%. The results of scanning electron micrographs and energy dispersive spectrometer tests indicate that the addition of graphene oxide accelerates the agglomeration of C-S-H gel produced by the reaction of calcareous sand cement mortar, forming a dense mesh-like structure, which enhances the unconfined compressive strength of the specimens. The oxygen-containing functional groups in graphene oxide are interlinked with the free Ca2+ in the hydration products, eventually producing crystals with the chemical formula (3CaO·Al2O3·CaSO4·12H2O). The generation of crystals leads to the reduction of pores inside the cement mortar and improves the specimen’s compression strength.

Ultrafast Synthesis of Graphene-Embedded Cyclodextrin-Metal-Organic Framework for Supramolecular Selective Absorbency and Supercapacitor Performance.

Limited by preparation time and ligand solubility, synthetic protocols for cyclodextrin-based metal-organic framework (CD-MOF), as well as subsequent derived materials with improved stability and properties, still remains a challenge. Herein, an ultrafast, environmentally friendly, and cost-effective microwave method is proposed, which is induced by graphene oxide (GO) to design CD-MOF/GOs. This applicable technique can control the crystal size of CD-MOFs from macro- to nanocrystals. CD-MOF/GOs are investigated as a new type of supramolecular adsorbent. It can selectively adsorb the dye molecule methylene green (MG) owing to the synergistic effect between the hydrophobic nanocavity of CDs, and the abundant O-containing functional groups of GO in the composites. Following high temperature calcination, the resulting N, S co-doped porous carbons derived from CD-MOF/GOs exhibit a high capacitance of 501 Fg-1 at 0.5 Ag-1 , as well as stable cycling stability with 90.1% capacity retention after 5000 cycles. The porous carbon exhibits good electrochemical performance due to its porous surface containing numerous electrochemically active sites after dye adsorption and carbonization. The design strategy by supramolecular incorporating a variety of active molecules into CD-MOFs optimizes the properties of their derived materials, furthering development toward the fabrication of zeitgeisty and high-performance energy storage devices.

Synthesis of multi donating sites grafted on graphene oxide nanosheets: Anti-corrosion study for mild steel in 1 M HCl with DFT calculations

The functionalization of graphene oxide of Sulphate and Phosphate functionalized graphene oxide nanomaterials were investigated as corrosion inhibitors for mild steel in HCl media by employing weight loss, electrochemical, surface, and computational methods. The graphene oxide (GO) was synthesized from industrial waste material graphite. The GO and seven functionalized GO were characterized by the FTIR, SEM, and EDX techniques. The amide-functionalized GO (N-G) exhibited good corrosion inhibition compared to sulfate (S-G) and phosphate (P-G) functionalized GO. It was further observed that the addition of sulfate and/or phosphate functional groups along with amide (NSP-G), showed an improvement in layering structure and exhibited the highest corrosion inhibition (93.78%). FTIR, SEM, EDX, and Contact Angle studies supported the formation of an inhibitive film of NSP-G on the mild steel surface. Density functional theory (DFT) results reveal that the addition of three functional groups in GO enhanced its interaction sites with the mild steel surface. Molecular dynamics (MD) simulation results show the predominantly chemisorption mechanism of NSP-G on the mild steel surface.

Samarium functionalized few-layer nano graphene oxide redox behavior, cytotoxicity and corrosion inhibition on Mg AZ31 alloy in 3.5% NaCl environment

The development of novel high-performance corrosion protection coatings for Mg alloys still represents a great research challenge. Strongly motivated by the lack of studies of Sm-containing materials as corrosion protectors/inhibitors and by successful studies of graphene oxide (GO)-based composites for this purpose, we developed the novel Sm-modified GO composite as a corrosion inhibition barrier layer on the Mg alloy AZ31 in 3.5% NaCl environment. Sm-functionalized graphene oxide materials showed excellent anticorrosion resistance and redox stabilities. The Fourier-transform infrared (FTIR) and Raman studies confirmed the presence of the GO functional groups. The field emission scanning electron microscopy (FESEM) and tunneling electron microscopy (TEM) studies suggested the presence of the few-layer nanographene oxide sheets. The redox stability studies showed the Sm-GO composite material to be stable at high voltage and to control anodic and cathode reactions at the alloy surface. The density functional theory (DFT) study supported the experimental results, suggesting high potential reactivity of the Sm-functionalized GO composite materials towards corrosive agents. Moreover, we determined the concentrations associated with the low risk of its cytotoxicity.

Comparison of effectiveness of blending and impregnation applications of dispersed nanoparticles on performance of cementitious composites

Blended or impregnated forms of nanomaterials in cementitious composites play a key role in determining mortar performance. In this study, the performance of graphene oxide (GO), silver nanoparticles (AgNPs), pristine multi-wall carbon nanotubes (MWCNTs), and functionalized MWCNTs impregnated and blended cementitious composites were compared using principal component analysis (PCA). The highest recorded compressive strength at 28 days was 39.1 MPa corresponding to the impregnation of carboxylated MWCNTs, representing a 29% improvement compared to reference cementitious composites while blending of pristine MWCNTs achieved a maximum compressive strength of 50.37 MPa, representing a 45% improvement over the reference. The group of GO, low-density AgNPs, and hydroxylated MWCNT-impregnated cementitious composites achieved the best sulfuric acid resistance, with an average compressive strength of 30.15 MPa, water absorption of 21.82%, porosity of 36.29%, and ultrasonic pulse velocity of 2.91 km/s due to preventing harmful sulfate ions entering their structure. After sulfuric acid exposure, a 5% compressive strength decrease occurred due to the presence of the functional groups of GO, hydroxylated MWCNTs, and small, low-density AgNPs on the surface of the cementitious composites. These results show that the impregnation method effectively improves cementitious composites' durability. Using PCA analysis, the pristine MWCNTs-blended cementitious composites were determined as the optimum specimen to obtain a durable mortar both pre- and post-acid exposure.

Significantly enhanced thermal conductivity of the aramid nanofiber composite film with GO and Ag nanoflakes for thermal management application

The development of composite materials with excellent thermal conductivity is attracting extensive attention to meet the increasing heat concentration challenges in both power and electronic equipment. Previous strategies for improving the thermal conductivities usually accompanied by the cost of mechanical strength. Herein, we propose a new strategy for developing both mechanically strong and thermally conductive composite films. The aramid nanofibers (ANF) are well prepared with introducing Ag nanoflakes and graphene oxide (GO) via vacuum-assisted filtration and hot-pressing treatment. Results indicate the synergistic effects of low dimension materials have resulted in a tightly arranged phonon network construction. The in-plane thermal conductivity of the prepared ANF/Ag/GO film reaches 9.84 W m−1 K−1, about 371% higher than that of pure ANF. Meanwhile, the strong hydrogen bond formed between the functional group of GO and the amide group of ANFs plays a synergistic strengthening and toughening role at the complex interface, and the tensile strength reaches 231 MPa. We believe that these findings shed some light on the design and fabrication of multifunctional materials for thermal management applications.