Polydopamine-modified Graphene Oxide Research Articles

Incorporating graphene oxide into COF membranes enables ultrahigh proton conductivity and ultralow H2 crossover

Proton exchange membranes (PEMs) are the core components of electrochemical hydrogen energy production, storage and conversion devices. It is a great challenge to develop PEMs with a combination of high proton conductivity, minimal H2 crossover and mechanical robustness for achieving high efficiency and long-term stability in these devices. Here, a co-assembled PEM composed of ionic covalent organic framework (iCOF) nanosheets and functionalized graphene oxide (GO) nanosheets was presented. The iCOF (TpPa-SO3H) nanosheets and polydopamine-modified graphene oxide (DGO) nanosheets were co-assembled into TpPa-SO3H/DGO mixed nanosheets with ultrahigh aspect ratio, which were readily further processed into TpPa-SO3H/DGO co-assembled membranes. The abundant and uniformly distributed –SO3H groups on TpPa-SO3H nanosheets and the acid-base pairs formed between TpPa-SO3H and DGO nanosheets promoted proton conduction significantly. Additionally, the dense structured DGO nanosheets inhibited H2 crossover remarkably, and the multiple interactions between TpPa-SO3H and DGO nanosheets enhanced mechanical strength. The resultant TpPa-SO3H/DGO co-assembled membrane exhibited an ultrahigh proton conductivity of 916.4 mS cm−1 (80 °C, 100% RH), an unprecedently low H2 crossover of 9.7 barrer and a sufficient tensile stress of 87.8 MPa. The enhanced proton conduction and H2 barrier property led to enhanced performance in both electrochemical hydrogen compression and single hydrogen fuel cells.

Electroactive Hydrogels with Photothermal/Photodynamic Effects for Effective Wound Healing Assisted by Polydopamine-Modified Graphene Oxide.

Antibacterial hydrogel wound dressings have attracted considerable attention in recent years. However, bacterial infections can occur at any point during the wound-healing process. There is a demand for hydrogels that possess on-demand antibacterial and excellent wound repair properties. Herein, we report a near-infrared (NIR)-light-responsive indocyanine green (ICG)-loaded polydopamine (PDA)-mediated graphene oxide (PGO) and amorphous calcium phosphate (CaP)-incorporated poly(vinyl alcohol) (PVA) hydrogel using a mussel-inspired approach. PGO was reduced by PDA, which endowed the hydrogel with electroactivity and provided abundant sites for loading ICG. Amorphous CaP was formed in situ in the PVA hydrogel to enhance its mechanical properties and biocompatibility. Taking advantage of the high photothermal and photodynamic efficiency of ICG-PGO, the ICG-PGO-CaP-PVA hydrogel exhibited fascinating on-demand antibacterial activity through NIR light irradiation. Moreover, the thermally induced gel-sol conversion of PVA accelerated the release of Ca ions and allowed the hydrogel to adapt to irregular wounds. Meanwhile, PGO endows the hydrogel with conductivity and cell affinity, which facilitate endogenous electrical signal transfer to control cell behavior. In vitro and in vivo studies demonstrated that the ICG-PGO-CaP-PVA hydrogel exhibited a strong tissue repair activity under NIR light irradiation. This mussel-inspired strategy offers a novel way to design hydrogel dressings for wound healing.

Wear and corrosion resistance of self-healing epoxy coatings filled by polydopamine-modified graphene oxide assembly of polysulfone double-walled microcapsules

In order to obtain a microcapsule self-healing coating with outstanding wear and corrosion resistance, a novel double-walled microcapsule filling epoxy resin (EP) coating was fabricated by assembling graphene oxide (GO) onto the outer shell layer of polysulfone (PSF) through polydopamine (PDA) modification. The surface of the as-prepared double-walled microcapsules was rough with a particle size of 60–70 μm and a wall thickness of 2–3 μm. With enhanced dispersion and compatibility, the double-walled microcapsule filling composite coating showed enhanced mechanical performance and thermal stability. The average friction coefficient and wear rate of the EP coating filled with 10.0 wt% of microcapsules were 37.0 % and 75.2 % lower than those of the pure EP coating, respectively. The impedance value and low-frequency impedance modulus of the coating were 17.5 and 10.7 times higher than those of pure EP after 7 d of immersion, respectively. And the scratch healing was more obvious with enhanced surface hydrophobicity after 72 h of self-repair. The excellent wear and corrosion resistance of the self-healing EP coating was attributed to the synergistic wear and corrosion resistance mechanism of the double-walled microcapsules.

Study on friction properties of silver/polydopamine modified graphene oxide nanocomposites as lubricant additive

According to the redox ability of dopamine in a weak alkaline environment, silver nanoparticles were uniformly loaded on the surface of polydopamine-modified graphene oxide (Ag/PGO). The results show that the base oil containing Ag/PGO nanoparticles exhibits a better tribological property than base oil. The maximum decrease in wear rate and friction coefficient at different temperatures amounted to 68% and 53.6%, respectively. The tribofilm containing C, O, N, and Ag exists and plays an important role in reducing friction and increasing wear resistance. Molecular dynamics simulations show that the microscopic oil film composed of Ag/PGO and n-hexadecane has low shear deformation during the shearing process, and the oil film has low interaction energy with the upper and lower shear walls.

In-situ polymerization of eco-friendly waterborne polyurethane/polydopamine-coated graphene oxide composites towards enhanced mechanical properties and UV resistance

Waterborne polyurethane (WPU) has attracted significant attention recently, considering its advantages of sustainability and low toxicity. However, fabricating WPU with excellent initial performance as well as extraordinary long-term stability is extremely challenging. In this study, we demonstrated the potential of polydopamine-modified graphene oxide (DGO) in the preparation of strong, tough, and highly durable WPU materials via in-situ polymerization. With the addition of only 2.0 wt% DGO, the tensile strength, and Young's modulus of WPU increased from 17.6 ± 2.6 to 56.5 ± 3.1 MPa (by 221%) and from 8.5 ± 1.1 MPa to 22.0 ± 0.8 MPa (by 159%), respectively. Compared with WPU, the degree of surface oxidation of the UV-aged WPU/DGO composites was substantially reduced from 174.3 to 19.5 (by 88% at maximum). Based on the cross-sectional analysis, the oxidation depth of the WPU/DGO composites was significantly reduced from 11.25 μm to 3.75 μm (by 66%). These improved properties originated not only from stronger interactions between DGO and WPU via the interfacial PDA layers and better dispersion of DGO, but also from the unique ultraviolet light absorption ability and free radical trapping ability of DGO. This facile yet environment-friendly in-situ synthesis technique is eco-sustainable and expected to promote the commercial availability of high-quality WPU and conserve natural resources.

Study on friction properties of polydopamine modified graphene oxide as lubricant additive

In this study, polydopamine-modified graphene oxide (PGO) nanomaterials were prepared based on the self-polymerization of dopamine in a weakly alkaline environment. In the friction experiment, the lubricants with 0.15 wt% PGO nanomaterials have optimal friction properties. Subsequently, X-ray photoelectron spectroscopy (XPS), X-ray energy spectroscopy (EDS), and laser Raman spectroscopy were performed on the wear scar. Compared to pure oil, the friction coefficient was reduced by 31%, and the trace width was reduced by 47.69%. In addition, molecular dynamics simulations showed that PGO has the lowest diffusion coefficient among n-hexadecane and the interaction energy between PGO and n-hexadecane molecules was the largest, and oil droplets containing PGO exhibited the best adsorption performance on the surface of the Si3N4/GCr15. The results showed that compared with other additives, PGO as a lubricant additive can play a significant role in reducing friction and anti-wear.

Polydopamine functionalized graphene oxide for high sensitivity micro-tapered long period fiber grating sensor and its application in detection Co2+ ions

We report a highly sensitive label-free chemical sensor for the detection of heavy metal ions. The sensor was derived from a micro-tapered long-period fiber grating (MTLPFG) functionalized by graphene oxide and poly-dopamine modified graphene oxide, respectively. Because of the combination of chemical bonding and optical tweezer effect, the materials were deposited on the MTLPFG fiber grating surface. The morphology and elemental composition of the nanocomposites were characterized by scanning electron microscope, Fourier-transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). Herein, we demonstrate a high sensitivity MTLPFG detection of cobalt ions in a large concentration range from 1 ppb to 107 ppb. The highest sensitivity of 2.4 × 10−3 dB∙ppb−1 at the PDA concentrations of 0.05 g∙L−1 was obtained by MTLPFG functionalized with PDA-GO (PDA-GO-MTLPFG). The result was significantly higher than GO-deposited MTLPFG (GO-MTLPFG). The proposed PDA-GO-MTLPFG demonstrates superior application value in chemical sensing fields.

Manipulating carrier arrangement in lamellar membrane channels towards highly enhanced proton conduction

Recent findings highlight the unique superiority of two-dimensional lamellar membranes in ion transport through the well-defined and stable interlayer channels. However, undesired channel chemical environment, such as low carrier density and random distribution, greatly limits their development as proton-conducting membranes. Herein, Nafion intercalated polydopamine-modified graphene oxide (ND-D) membranes are prepared, followed by thermal rearrangement-electrostatic induction to manipulate –SO3H group arrangement in interlayer channels. Experiments and molecular dynamics simulations demonstrate the specific process mechanism of carrier rearrangement: heat treatment promotes the movement of Nafion chains, and then induces their acid groups to enrich near the –NH2/–NH– groups on channel wall. Such carrier arrangement creates efficient and stable interfacial channels for proton conduction. This novel membrane, therefore, achieves the proton conductivity of 309 and 55.4 mS cm−1 under 100% and 40% RH, respectively, outclassing those of benchmark Nafion membrane. This further permits a 130% improvement in hydrogen fuel cell performance. Meanwhile, the carrier rearrangement imparts over two times’ enhancement in interlayer interaction and hence obviously enhanced membrane stability. Furthermore, a similar sulfonated poly(ether ether ketone) intercalated lamellar membrane is prepared to prove the universality of this strategy. The elaboration of carrier rearrangement in confined channels may pave a way for the rational design of high-efficiency membrane materials.

Enhanced wound repair ability of arginine-chitosan nanocomposite membrane through the antimicrobial peptides-loaded polydopamine-modified graphene oxide

Skin wound healing is a complicated and lengthy process, which is influenced by multiple factors and need a suitable cellular micro-environment. For skin wound, wound dressings remain a cornerstone of dermatologic therapy at present. The dressing material can create an effective protective environment for the wound, and the interactions between the dressing and the wound has a great impact on the wound healing efficiency. An ideal wound dressing materials should have good biocompatibility, moisturizing property, antibacterial property and mechanical strength, and can effectively prevent wound infection and promote wound healing. In this study, in order to design wound dressing materials endowed with excellent antibacterial and tissue repair properties, we attempted to load antimicrobial peptides onto dopmine-modified graphene oxide (PDA@GO) using lysozyme (ly) as a model drug. Then, functionalized GO was used to the surface modification of arginine-modified chitosan (CS-Arg) membrane. To evaluate the potential of the prepared nanocomposite membrane in wound dressing application, the surface morphology, hydrophilic, mechanical properties, antimicrobial activity, and cytocompatibility of the resulting nanocomposite membrane were analyzed. The results revealed that prepared nanocomposite membrane exhibited excellent hydrophilic, mechanical strength and antimicrobial activity, which can effectively promote cell growth and adhesion. In particular, using PDA@GO as drug carrier can effectively maintain the activity of antimicrobial peptides, and can maximize the antibacterial properties of the nanocomposite membrane. Finally, we used rat full-thickness wound models to observe wound healing, and the surface interactions between the prepared nanocomposite membrane and the wound. The results indicated that nanocomposite membrane can obviously accelerated wound closure, and the wounds showed reduced inflammation, improved angiogenesis and accelerated re-epithelialization. Therefore, incorporation of antimicrobial peptides-functionalize graphene oxide (ly-PDA@GO) into CS-Arg membrane was a viable strategy for fabricating excellent wound dressing. Together, this study not only prepared a wound dressing with excellent tissue repair ability, but also provided a novel idea for the development of graphene oxide-based antibacterial dressing.

Lithiated nanosheets hybridized solid polymer electrolyte to construct Li+ conduction highways for advanced all-solid-state lithium battery

Solid-state electrolyte is a key component of high-energy-density and security all-solid-state lithium metal battery. However, the present solid polymer electrolyte (SPE) often suffers from the trade-off between ionic conductivity and mechanical stability. To this end, lithiated polydopamine-modified graphene oxide nanosheets (LiDGO) are fabricated, and incorporated into the representative poly(ethylene oxide) (PEO) matrix to prepare hybrid solid polymer electrolyte (HSPE). Despite the decreased crystallinity of PEO, the intrinsic advantage of organic-inorganic hybridization affords PEO-based HSPE highly improved mechanical stability. The tensile strength and elongation at break of HSPE are, respectively, 237% and 133% higher than those of blank PEO. The constructed long-range conduction pathways with locally concentrated Li+ at PEO-LiDGO interfaces impart HSPE highly enhanced ionic conductivity. The ionic conductivity reaches 3.4 × 10−5 S cm−1 at 30 °C, 10 times higher than that of blank PEO. These then bring excellent battery performances. The assembled battery achieves a discharge capacity of ~156 mAh g−1 after 200 cycles with ultra-high capacity retention of 98.7%. The strategy of utilizing lithiated nanosheets to address the trade-off between ionic conductivity and mechanical stability of SPE may pave the way for the development of high performance all-solid-state lithium metal batteries.

Corrigendum

International Journal of Energy ResearchVolume 44, Issue 8 p. 7103-7103 CORRIGENDUMFree Access Corrigendum This article corrects the following: TiNb2O7 microsphere anchored by polydopamine-modified graphene oxide as a superior anode material in lithium-ion batteries Hyeongwoo Kim, Yongheum Lee, Dongjin Byun, Wonchang Choi, Volume 44Issue 6International Journal of Energy Research pages: 4986-4996 First Published online: February 26, 2020 First published: 16 June 2020 https://doi.org/10.1002/er.5617AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat ‘TiNb2O7 microsphere anchored by polydopamine-modified graphene oxide as a superior anode material in lithium-ion batteries’ International Journal of Energy Research 2020;44:4986-4996. Hyeongwoo Kim | Yongheum Lee | Dongjin Byun | Wonchang Choi In this article by Kim et al1 there was an error in the grant number. The incorrect grant number was given (NRF-2020R1A2C1004949). This is corrected to NRF-2018R1A2B2007081. The authors apologize for any inconvenience that it may have caused. REFERENCE 1Kim H, Lee Y, Byun D, Choi W. TiNb2O7 microsphere anchored by polydopamine-modified graphene oxide as a superior anode material in lithium-ion batteries. Int J Energy Res. 2020; 44(6): 4986- 4996. Wiley Online LibraryCASWeb of Science®Google Scholar Volume44, Issue825 June 2020Pages 7103-7103 ReferencesRelatedInformation

Self-powered forest fire alarm system based on impedance matching effect between triboelectric nanogenerator and thermosensitive sensor

Abstract As worldwide forest fire frequently causes a serious threat to forest resources and global climate change, novel early forest fire monitoring and detection technologies are urgently required to explore. Herein, a self-powered forest fire alarm system (FFAS) is proposed by coupling thermosensitive effect and triboelectric effect as an aim of effective forest fire monitoring and detecting. The FFAS is fabricated as a self-powered early forest fire monitoring and detection system by connecting a spherical free-standingmode triboelectric nanogenerator (S-TENG) as power source with polydopamine-modified graphene oxide (P-GO) as thermosensitive sensor and commercial LEDs as alarm. When encountering an open fire or abnormal high temperature the thermosensitive sensor based on P-GO can be in-situ thermally reduced, inducing an obvious transition in electrical resistance. Thus, the output voltage of S-TENG can be tuned by the impedance matching effect between special output characteristics of TENG and working status of thermosensitive sensor, and then can directly light up the LEDs as alarm. Furthermore, the FFAS achieves a low temperature response (160 °C), rapid response time (~3 s), and especially no external power supply. Consequently, the FFAS based on impedance matching effect between TENG and thermosensitive sensor would provide a real-time, rapidly responsive, and self-powered monitoring strategy for the early forest fire warning and detection.

Modification of various carbons with various metal oxides and noble metal compositions as electrocatalysts for ethanol oxidation

ABSTRACT The modification of various carbons with various metal oxides and noble metal composites was performed to prepare electrocatalysts, and the catalysts were further investigated for ethanol electro-oxidation. The catalyst activity and stability were studied by cyclic voltammetry (CV) and chronoamperometry (CA), respectively. First, various metal oxides (e.g., TiO2, CeO2 and MnO2) were prepared on a graphene oxide (GO) support. Pt on TiO2 with a GO support (Pt/TiO2-GO) provided a higher current density and long-term stability than the other catalysts. Second, TiO2 was prepared on various carbons (e.g., graphite (G), graphite oxide (GTO), GO and polydopamine (PDA)-modified GO (PDA-GO)), and the corresponding electrocatalytic activities were determined. Pt/TiO2-PDA-GO showed the highest activity and stability for oxidation. Consequently, TiO2-PDA-GO was chosen as a support for further studies on the optimal composition of bimetallic catalysts (xPtyPd/TiO2-PDA-GO). 4Pt2Pd/TiO2-PDA-GO showed the highest performance for ethanol oxidation. The prepared M/TiO2-C catalysts were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and transmission electron microscopy (TEM). The results showed that the dispersed nanoparticles were loaded on the modified carbon supports. From electrochemical measurements, the prepared electrocatalysts showed improved electrocatalytic activities in terms of low onset potential and high current density and stability.

A facile bionic strategy towards Gd (III)-imprinted membranes via interlaced stacking of one-dimensional/two-dimensional nanocomposite materials

Rapid development of rare earth industry has led to an increasing demand for highly purified rare earth elements (REEs). The combination of ion-imprinted technique (IIT) and membrane separation technique (MST) is recently regarded as a promising strategy for selectively separating specific ions from multiple REEs. In this work, a facile bionic strategy for preparation of Gd (III)-imprinted membranes (GIMs) were developed via interlaced stacking of one-dimensional Gd (III)-imprinted carbon nanotubes (GICNTs) and two-dimensional polydopamine-modified graphene oxide ([email protected]). Polydopamine was synthesized on graphene oxide to large enhance the interfacial adhesion, and ion-imprinting polymerization is implemented on carbon nanotubes (CNTs) by direct cross-link of linear polymers. The obtained materials are characterized in detail by FTIR, SEM, TEM and AFM to explorer the evolution of chemical composition and morphology. Selectivity towards Gd (III) is obtained by isothermal adsorption, kinetic adsorption and time-depended permeation. Isothermal and kinetic models are fitted with adsorption data to obtain the mechanism of selective separation on GIMs. The as-synthesized GIMs with high permeation selectivity (2.91 and 2.49) towards Gd (III) and stable permeation regeneration would potentially be applied to separation and purification of specific ions form multiple REEs.

Robust and Recyclable Two-Dimensional Nanobiocatalysts for Biphasic Reactions in Pickering Emulsions

In this study, a facile, yet effective surface-engineering method was reported to confer graphene oxide (GO) nanosheets with amphiphilic feature and numerous binding sites toward enzymes for biphasic reactions in Pickering emulsions. Briefly, the surface of GO nanosheet is first modified and simultaneously reduced by polydopamine to endow with catechol groups. A portion of catechol groups is utilized to anchor zeolitic imidazolate framework 8 (ZIF-8) nanoparticles onto the polydopamine-modified graphene oxide (P-rGO) nanosheets through Zn2+–catechol coordination. The remaining uncoordinated catechol groups in P-rGO nanosheets are utilized to immobilize lipase onto the P-rGO nanosheets through chemical conjugation. The resulting two-dimensional P-rGO/ZIF-8/Lipase nanobiocatalysts with an enzyme loading percent values of 34.05–48.75% could be spontaneously assembled at the oil/water interface, which were then utilized to catalyze the hydrolysis of water-insoluble p-nitrophenyl palmitate (p-NPP) into water-s...

Synthesis and properties of polyimide nanocomposite containing dopamine-modified graphene oxide

Polyimide (PI)/graphene oxide (GO) nanocomposites with different loads of polydopamine-modified graphene oxide (PI/PDA-GO) were prepared. Meanwhile, the as-prepared PI/PDA-GO nanocomposites were compared with pure PI in terms of their morphologies, thermal and mechanical properties. Only a minor mass fraction of PDA-GO was required to enhance the mechanical and thermal properties of PI. The tensile strength of 1 wt% PDA-GO/PI was increased by 12% and the tensile modulus of 1 wt% PDA-GO/PI nanocomposites was increased by 25% compared to those of pure PI. Vickers hardness of the PI hybrid films increased with PDA-GO load and the maximum enhancement in Vickers hardness was observed at 2 wt% PDA-GO loading. On the other hand, the storage modulus of 1 wt% PDA-GO/PI was increased by 54% than that of neat PI. In consideration of the facile preparation of PDA-coated GO, superior physical properties over neat PI, PI/PDA-GO nanocomposites showed promising applications as functional films or composites.

A biomimetic approach to improving tribological properties of hybrid PTFE/Nomex fabric/phenolic composites

Interfacial strength between reinforcement and polymer matrix and dispersion of lubricant fillers in polymer composites are vital properties in determining the mechanical behaviors and tribological performance. In this work, a facile biomimetic method was employed to improve the interfacial strength between hybrid PTFE/Nomex fabric and phenolic resin as well as the dispersion of carbon carbonaceous in phenolic composite. Dopamine is the main component of mussel adhesive proteins which can easily attach on substrate surface by self-polymerization under weak basic buffer solution. Hence, polydopamine modified graphene oxide (D-rGO) and multi-walled carbon nanotubes (D-MWCNTs) were incorporated into polydopamine functionalized hybrid PTFE/Nomex fabric (D-fabric) composite to improve the tribological performance of the phenolic composite. XPS, TGA, SEM, and TEM characteristics illustrated that the hybrid PTFE/Nomex fabric, graphene oxide (GO), and carbon nanotube (MWCNTs) were successfully functionalized by polydopamine. More importantly, wear test results showed that D-rGO (or D-MWCNTs) reinforced D-fabric phenolic composite exhibited excellent tribological performance. The wear test results and corresponding wear mechanisms of the hybrid PTFE/Nomex fabric composite were discussed in terms of characterizations.

Polydopamine-modified graphene oxide nanocomposite membrane for proton exchange membrane fuel cell under anhydrous conditions

A new approach to the facile preparation of anhydrous proton exchange membrane (PEM) enabled by artificial acid–base pairs is presented herein. Inspired by the bioadhesion of mussel, polydopamine-modified graphene oxide (DGO) sheets bearing –NH2 and –NH– groups are fabricated and then incorporated into sulfonated poly(ether ether ketone) (SPEEK) matrix to prepare the nanocomposite membrane. The DGO sheets are interconnected and homogeneously dispersed in SPEEK matrix, which provides unique rearrangement of the nanophase-separated structure and chain packing of nanocomposite membrane through interfacial electrostatic attractions. These attractions meanwhile induce the generation of acid–base pairs along the SPEEK–DGO interface, which then serve as long-range and low-energy-barrier pathways for proton hopping, imparting an enhanced proton transfer via the Grotthuss mechanism. In particular, under both hydrated and anhydrous conditions, the nanocomposite membrane exhibits much higher proton conductivity than the polymer control membrane. The enhanced proton conductivity results in the nanocomposite membrane having elevated cell performances under 120 °C and hydrous conditions, yielding a 47% increase in maximum current density and a 38% increase in maximum power density. Together with the stable conduction property, these results guarantee the nanocomposite membrane's promising prospects in high-performance fuel cell under anhydrous and elevated temperature conditions.