Polydopamine Functionalized Graphene Oxide Research Articles

Cotton Fabric-Reinforced Hydrogels with Excellent Mechanical and Broad-Spectrum Photothermal Antibacterial Properties

Antibacterial hydrogel wound dressings hold great potential in eliminating bacteria and accelerating the healing process. However, it remains a challenge to fabricate hydrogel wound dressings that simultaneously exhibit excellent mechanical and photothermal antibacterial properties. Here we report the development of polydopamine-functionalized graphene oxide (rGO@PDA)/calcium alginate (CA)/Polypyrrole (PPy) cotton fabric-reinforced hydrogels (abbreviated as rGO@PDA/CA/PPy FHs) for tackling bacterial infections. The mechanical properties of hydrogels were greatly enhanced by cotton fabric reinforcement and an interpenetrating structure, while excellent broad-spectrum photothermal antibacterial properties based on the photothermal effect were obtained by incorporating PPy and rGO@PDA. Results indicated that rGO@PDA/CA/PPy FHs exhibited superior tensile strength in both the warp (289 ± 62.1 N) and weft directions (142 ± 23.0 N), similarly to cotton fabric. By incorporating PPy and rGO@PDA, the swelling ratio was significantly decreased from 673.5% to 236.6%, while photothermal conversion performance was significantly enhanced with a temperature elevated to 45.0 °C. Due to the synergistic photothermal properties of rGO@PDA and PPy, rGO@PDA/CA/PPy FHs exhibited excellent bacteria-eliminating efficiency for S. aureus (0.57%) and E. coli (3.58%) after exposure to NIR for 20 min. We believe that the design of fabric-reinforced hydrogels could serve as a guideline for developing hydrogel wound dressings with improved mechanical properties and broad-spectrum photothermal antibacterial properties for infected-wound treatment.

Photocatalytic bio‐inspired PDA‐RGO/g‐C3N4 nanocomposite incorporated PES membrane for removal of environmental antibiotic pollutants

AbstractBACKGROUNDMembrane technology makes it more suitable for the treatment of environmental polluted organic wastewater. Membrane fouling is one of the major concerns in commercial membranes. To overcome this issue, photocatalytic nanomaterials are embedded into the membrane to enhance its surface nature and reusability. In this investigation, polydopamine functionalized graphene oxide (PDA‐RGO), graphite carbon nitride (g‐C3N4) and PDA‐RGO/g‐C3N4 nanomaterials were incorporated within polyethersulfone membrane fabricated via a phase inversion technique. These as‐prepared membranes’ functional groups and surface morphologies were investigated by Fourier transform infrared (FTIR) spectroscopy, atomic force microscopy (AFM) and field emission electron microscopy (FESEM). These as‐prepared membranes were investigated for photocatalytic activity under visible‐light‐driven photodegradation by environmental pollutants such as Rhodamine B (RhB) and Norfloxacin (NOR).RESULTSCompared with pristine PES membrane, the PDA‐RGO/g‐C3N4‐PES nanocomposite membrane showed higher photocatalytic activity for Rhodamine B 94.6% and Norfloxacin 96.8%, also reached greater water flux 189 L m−2 h−1. Therefore, the bio‐inspired nanocomposite‐modified PDA‐RGO/g‐C3N4 photocatalytic membrane could have huge potential in processing environmentally polluted water.CONCLUSIONSPDA‐RGO/g‐C3N4‐PES nanocomposite membrane improved the membrane hydrophilicity, water flow, anti‐fouling performance, rejection studies and photocatalytic degradation than the pristine membrane. The synergistic result of PDA‐RGO and g‐C3N4 exhibits better photodegradation efficiency of the membrane towards environmental pollutants. © 2024 Society of Chemical Industry (SCI).

Static and dynamic mechanical properties of polyurea nanocomposites reinforced by polydopamine functionalized graphene oxide

Polyurea (PU) materials are widely used in civil and military fields owing to their excellent weather, wear and corrosion resistance, impact resistance and energy absorption ability. In this study, polyurea nanocomposites integrated with polydopamine functionalized graphene oxide (GO@PDA) were reported. The functionalization of graphene oxide (GO) with polydopamine was achieved under mild conditions to optimize the dispersion and interfacial compatibility of GO within the PU matrix, thereby reinforcing the mechanical properties of PU materials. The quasi-static and dynamic compressive behaviors of PU nanocomposites under various strain rates (0.001–7000 s−1) were comprehensively investigated through a universal testing machine and split Hopkinson pressure bar (SHPB), respectively. Results revealed a significant enhancement in the strain-rate sensitivity, flow strength, yield strength, and strain energy density with the increasing strain rate and GO@PDA content. Particularly, at a strain rate of 7000 s−1, GO@PDA1.0%/PU nanocomposite exhibited a remarkable increase of 33% and 54% in flow strength and yield strength, respectively. This remarable enhancement was closely related with the effective dispersion and superior interfacial compatibility between GO@PDA and PU matrix. Eventually, to offer a comprehensive understanding of the mechanical behavior of PU nanocomposites, a visco-hyperelastic intrinsic model was employed to accurately capture the mechanical response under various strain rates.

Enhancing epoxy coating corrosion resistance with a novel MoS2-modified polydopamine functionalized graphene oxide nanocomposite

Environmental-friendly epoxy (EP) composite coatings are regarded as distinguished candidates for preventing metal corrosion. In this paper, we synthesized a novel GO-PDA-MoS2/EP nanocomposite coating system by modifying dopamine (PDA) functionalized graphene oxide (GO) with MoS2. Here, the effect of different MoS2 additions on the corrosion resistant properties of coatings was investigated by altering the ratio of MoS2 to GO-PDA via electrochemical measurements, long-duration immersion experiments, and water contact angle tests. The results indicated that 0.3 wt.% MoS2 can substantially enhance the interfacial compatibility between EP and GO-PDA and the GO-PDA-MoS2-0.3 wt.%/EP coating presented optimum corrosion resistant properties. Specifically, the impedance modulus (|Z|) of the GO-PDA-MoS2-0.3 wt.%/EP coating still reached 2.36 × 107 Ω·cm2 after 30 days immersed, which was two orders of magnitude higher than pure EP coatings. This work demonstrates a novel economical and environmental scheme that MoS2 can be employed to enhance the corrosion resistant properties and improve the interfacial interactions of EP coatings.

Injectable hydrogel based on silk fibroin/carboxymethyl cellulose/agarose containing polydopamine functionalized graphene oxide with conductivity, hemostasis, antibacterial, and anti-oxidant properties for full-thickness burn healing

Overcoming bacterial infections and promoting wound healing are significant challenges in clinical practice and fundamental research. This study developed a series of enzymatic crosslinking injectable hydrogels based on silk fibroin (SF), carboxymethyl cellulose (CMC), and agarose, with the addition of polydopamine functionalized graphene oxide (GO@PDA) to endow the hydrogel with suitable conductivity and antimicrobial activity. The hydrogels exhibited suitable gelation time, stable mechanical and rheological properties, high water absorbency, and hemostatic properties. Biocompatibility was also confirmed through various assays. After loading the antibiotic vancomycin hydrochloride, the hydrogels showed sustained release and good antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA). The fast gelation time and desirable tissue-covering ability of the hydrogels allowed for a good hemostatic effect in a rat liver trauma model. In a rat full-thickness burn wound model, the hydrogels exhibited an excellent treatment effect, leading to significantly enhanced wound closure, collagen deposition, and granulation tissue formation, as well as neovascularization and anti-inflammatory effects. In conclusion, the antibacterial electroactive injectable hydrogel dressing, with its multifunctional properties, significantly promoted the in vivo wound healing process, making it an excellent candidate for full-thickness skin wound healing.

Sensitive label-free hemoglobin detection based on polydopamine functionalized graphene oxide coated micro-tapered long-period fiber grating

The GO and PDA-GO functionalized TLPG based sensitive and label-free optical biosensor for human hemoglobin detection was demonstrated. The PDA-GO and GO were separately deposited onto fiber surface, the deposited materials provide a large number of binding sites to adsorb the hemoglobin and can further change the RI of fiber surface, and can provide more binding sites owing to the large specific surface area, and it exhibits higher sensing sensitivity of 3.14 mg/mL and the LOD can reach 0.057 mg/mL. In addition, the sensing was carried out in the presence of inference compounds and also proved its ideal reusability. The usage of PDA-GO as a bio-interface layer enables strong interference of optical waves as well as excellent biocompatibility, which is considered to be valuable for biosensing applications.

Polydopamine functionalized graphene oxide membrane with the sandwich structure for osmotic energy conversion.

Ion-selective membrane is the key component for osmotic energy conversion. Nanofluid channels based on two-dimensional materials have advantages of facile preparation, tunable channel size, and easy upscaling, which is promising for efficient osmotic energy harvesting. However, further improvement of the output power is hindered by the low ion sensitivity for the limited charge density. Herein, we demonstrate the preparation of a cation-selective polydopamine-coated graphene oxide composite membrane with the sandwich structure by a simple interfacial polymerization technique, which greatly improves the surface charge density and further generates a power density of 3.4W/m2 under river water and seawater. The GO membrane is firstly fabricated to function as the supporting layer and provide the reaction sites. And the ultrathin selective layer of the polydopamine membrane is chemically bonded with the GO layer by the in-situ polymerization on both sides of the GO membrane. The sandwiched nanofluidic membrane with ultrahigh charge density exhibits both high cation selectivity and ionic conductivity, benefiting the performance of osmotic energy conversion. The economic, easy-prepared method of the sandwiched nanofluidic membrane provides a promising strategy for high-performance osmotic energy conversion.

Polydopamine functionalized graphene oxide as an effective corrosion inhibitor of carbon steel in HCl solution

Polydopamine functionalized graphene oxide as an effective corrosion inhibitor of carbon steel in HCl solution

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.

Polydopamine Functionalized Graphene Oxide as Membrane Nanofiller: Spectral and Structural Studies.

High-degree functionalization of graphene oxide (GO) nanoparticles (NPs) using polydopamine (PDA) was conducted to produce polydopamine functionalized graphene oxide nanoparticles (GO-PDA NPs). Aiming to explore their potential use as nanofiller in membrane separation processes, the spectral and structural properties of GO-PDA NPs were comprehensively analyzed. GO NPs were first prepared by the oxidation of graphite via a modified Hummers method. The obtained GO NPs were then functionalized with PDA using a GO:PDA ratio of 1:2 to obtain highly aminated GO NPs. The structural change was evaluated using XRD, FTIR-UATR, Raman spectroscopy, SEM and TEM. Several bands have emerged in the FTIR spectra of GO-PDA attributed to the amine groups of PDA confirming the high functionalization degree of GO NPs. Raman spectra and XRD patterns showed different crystalline structures and defects and higher interlayer spacing of GO-PDA. The change in elemental compositions was confirmed by XPS and CHNSO elemental analysis and showed an emerging N 1s core-level in the GO-PDA survey spectra corresponding to the amine groups of PDA. GO-PDA NPs showed better dispersibility in polar and nonpolar solvents expanding their potential utilization for different purposes. Furthermore, GO and GO-PDA-coated membranes were prepared via pressure-assisted self-assembly technique (PAS) using low concentrations of NPs (1 wt. %). Contact angle measurements showed excellent hydrophilic properties of GO-PDA with an average contact angle of (27.8°).

Green synthesis of highly dispersed Ag nanoparticles on polydopamine-functionalized graphene oxide and their high catalytic reduction reaction

Herein, we introduce a tailored mussel-inspired concept to facilitate the sustainable immobilization of silver nanoparticles (Ag NPs), which are accepted for the effectiveness in controlling the silver nanoparticle density and morphology onto the surface of the graphene oxide sheets (GO). Immobilization of Ag NPs on polydopamine (PDOP) functionalized GO is performed via the self-polymerization of dopamine by a facile in situ reduction method. The catalytic ability of the as-synthesized [email protected] catalyst was searched for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) as a class of widespread toxic organic pollutant. The dopamine-mediated graphene hybrid with Ag NPs exhibited excellent catalytic reduction activities due to promoting the electron transfer and the dispersion of small-sized silver nanoparticles imposed upon the surface of graphene. The resulting hybrid exhibited 15 times higher catalytic activity than that of the graphene/silver hybrid without any modification.

Novel polysulfone ultrafiltration membranes incorporating polydopamine functionalized graphene oxide with enhanced flux and fouling resistance

Novel PSF composite UF membranes incorporating low loadings of polydopamine-functionalized graphene oxide particles (rGO-PDA) were fabricated and investigated. The functionalization was confirmed using FTIR-UATR, Raman spectra, XPS, and SEM. Pristine PSF, PSF/GO, and PSF/rGO-PDA MMMs were then prepared using the phase inversion technique and analysed using FTIR, SEM, AFM, and contact angle (CA). The cross-section SEM images showed better distribution of rGO-PDA particles in the pores and polymer wall whereas the pristine GO particles aggregate and partially block the pores. Thus, the pure water flux increased with the addition of rGO-PDA without affecting the rejection properties, while the flux decreased with the embedding of pristine GO particles. The highest pure water permeability (PWP) was obtained with PSF/rGO-PDA-0.1 to be approximately twice that of the pristine PSF and PSF/GO-0.1. All membranes exhibited complete rejection of BSA and HA, and showed almost similar performance against different dyes. The FRRs of the pristine PSF after three fouling cycles (FRR3) against BSA and HA were recorded to be 57.8% and 70.7% respectively. FRR3 was enhanced by around 30% with PSF/rGO-PDA composites. The MMMs prepared in this work are expected to have great potential on ultrafiltration and similar studies on other membrane processes.

Thermal properties and shape stabilization of epoxidized methoxy polyethylene glycol composite PCMs tailored by polydopamine-functionalized graphene oxide

A series of composite phase change materials (cPCMs) are fabricated through the one-pot method with the epoxidized methoxy polyethylene glycol (EmPEG) as the thermal energy unit and polydopamine-reduced graphene oxide (PDA-rGO) nanosheets as the interfacial enhancement. Structure and thermal properties such as phase change enthalpy, thermal repeatability, and light-to-thermal conversion capacity of EmPEG/PDA-rGO cPCMs with PDA-rGO content varying from 0.5 to 4 wt% have been detailed discussed. A superior stabilization performance of EmPEG/PDA-rGO cPCMs to pristine EmPEG is demonstrated based on the interfacial action from the incorporated PDA-rGO nanosheets. EmPEG/PDA-rGO-3 presents good structure-stabilized behavior after 100 heating-cooling cycles, and no liquid leakage appears up to 105 °C. In the meantime, EmPEG/PDA-rGO-3 illustrates a stable thermal reliability and thermal charging/discharging rate, and the light-to-thermal conversion efficiency reaches 96% under the 100 mW/cm2 irradiation. Thus, the structure-stabilized EmPEG/PDA-rGO cPCMs tuned by the interfacial interaction demonstrates the promising application in the field of the thermal energy storage and solar energy conversion.

Polydopamine-functionalized graphene oxide compounded with polyvinyl alcohol/chitosan hydrogels on the recyclable adsorption of cu(II), Pb(II) and cd(II) from aqueous solution

Polydopamine-Functionalized graphene oxide (PDA-GO) was used to form Polyvinyl Alcohol/Chitosan/PDA-GO (PVA/CS/PDA-GO) hydrogels. FTIR, TGA and SEM investigation showed that PDA had been successfully loaded on graphene oxide nanosheets. Adsorption of metal ions onto the novel PVA/CS/PDA-GO hydrogel beads with variations in pH, contact time, initial metal concentration and temperature had been investigated. Adsorption data were well accurately described by Langmuir isotherm and pseudo-second-order kinetic model at the optimum pH 5.5. The maximum adsorption capacities of the PVA/CS/PDA-GO were 210.94 mg·g−1, 236.20 mg·g−1 and 214.98 mg·g−1 for Cu(II), Pb(II) and Cd(II) ions with 40 C, respectively. Meanwhile, desorption efficiency and reusability of the adsorbents were assessed on basis of six consecutive adsorption-desorption cycles. This work provides a simple and environmentally friendly method to obtain the PVA/CS/PDA-GO hydrogel beads, which really would be a potential recyclable adsorbent for removal of hazardous metal ions in waste water.

Polydopamine functionalized graphene oxide nanocomposites reinforced the corrosion protection and adhesion properties of waterborne polyurethane coatings

In this work, a polydopamine (PDA)-functionalized graphene oxide (GO) nanocomposite was prepared by a simple and eco-friendly approach. The results recorded via FTIR, UV–vis absorbance spectroscopy, Raman, XPS spectral, as well as atomic force microscope (AFM) demonstrated the effective modification and overlay of PDA on the surface of GO. GO-PDA can be stably dispersed in aqueous solution, and GO-PDA was incorporated into waterborne polyurethane (WPU) by solution blending. The examinations of particle size analysis and zeta potential showed that the incorporation of GO-PDA can effectively improve the uniformity and stability of polyurethane aqueous dispersion. The observation results of SEM verified that PDA promoted the uniform dispersion of GO nanosheets in polymer coatings. The electrochemical impedance spectroscopy and salt spray test of the steel substrates coated with composite coatings confirmed that the incorporation of 0.5 wt% GO-PDA significantly enhanced the anti-corrosion performance of WPU. Compared with previous reports, the incorporation amount of GO-PDA was drastically reduced, and the corrosion protection of coating was effectively improved. In addition, the pull-off and contact angle tests also demonstrated improved adhesion strength and hydrophobicity of the coating. Only water was used as solvent in the whole preparation process of coating and its excellent corrosion protection make it promising in engineering.

Polydopamine-Functionalized Graphene Oxide Loaded with Gold Nanostars and Doxorubicin for Combined Photothermal and Chemotherapy of Metastatic Breast Cancer.

Breast cancer is the leading cancer type diagnosed in the female population, and cancer metastasis is the main reason for cancer-caused mortality. A novel nanoplatform is herein presented integrating polydopamine-functionalized nanosized reduced graphene oxide (NRGO), gold nanostars (GNS), and doxorubicin (DOX) (denoted as NRGO-GNS@DOX) for combinational treatment of metastatic breast cancer. Upon localized near infrared (NIR) laser irradiation, the NRGO-GNS@DOX nanocomposites induce significant cytotoxicity in 4T1 breast cancer cells due to a cumulative therapy effect of NRGO-GNS-elicited hyperthermia and DOX-induced cytotoxicity. Antitumor studies in orthotopic 4T1 breast tumor-bearing nude mice demonstrate that NRGO-GNS@DOX in combination with NIR laser irradiation inhibit the tumor growth and suppress the lung metastasis. Contribution of DOX-caused apoptosis of the cancer cells and hyperthermia-induced deconstruction of the tumor-associated blood vessels may account for the superior antitumor performance of the NRGO-GNS@DOX nanocomposites. These results imply a good potential of NRGO-GNS@DOX for combined photothermal and chemotherapy of the metastatic cancer.

Mussel-Inspired Polydopamine-Functionalized Graphene as a Conductive Adhesion Promoter and Protective Layer for Silver Nanowire Transparent Electrodes

For the scalable fabrication of transparent electrodes and optoelectronic devices, excellent adhesion between the conductive films and the substrates is essential. In this work, a novel mussel-inspired polydopamine-functionalized graphene/silver nanowire hybrid nanomaterial for transparent electrodes was fabricated in a facile manner. Graphene oxide (GO) was functionalized and reduced by polydopamine while remaining stable in water without precipitation. It is shown that the polydopamine-functionalized GO (PFGO) film adhered to the substrate much more easily and more uniformly than the GO film. The PFGO film had a sheet resistance of ∼3.46 × 10(8) Ω/sq and a transparency of 78.2%, with excellent thermal and chemical stability; these characteristics are appropriate for antistatic coatings. Further reduced PFGO (RPFGO) as a conductive adhesion promoter and protective layer for the Ag nanowire (AgNW) significantly enhanced the adhesion force between AgNW networks and the substrate. The RPFGO-AgNW electrode was found to have a sheet resistance of 63 Ω/sq and a transparency of 70.5%. Moreover, the long-term stability of the RPFGO-AgNW electrode was greatly enhanced via the effective protection of the AgNW by RPFGO. These solution-processed antistatic coatings and electrodes have tremendous potential in the applications of optoelectronic devices as a result of their low production cost and facile processing.

Immobilization of glucose oxidase on polydopamine-functionalized graphene oxide.

In this study, graphene oxide (GO) was modified with dopamine to create a matrix for enzyme immobilization. Dopamine can self-polymerize to get polydopamine (PDA) and coated on GO surface. At the same time, GO was reduced to get PDA/rGO biocomposite. The PDA/rGO may offer adherent surface for enzyme immobilization. Glucose oxidase (GOD), an oxidoreductase, was chosen as model enzyme and can be easily immobilized on PDA/rGO. Experimental results indicated that the thermal and pH stability as well as the storage stability and resistance toward the denaturing agents of GOD were significantly improved after immobilization. The Michaelis constant (K m) of the immobilized GOD was very close to that of the free GOD. This study offers a versatile approach for deposition of biopolymer on GO and provides a way for enzyme immobilization. Hopefully, the immobilized GOD may be further applied for biosensor and biofuel cell applications.

Facile electrochemical synthesis of polydopamine-incorporated graphene oxide/PEDOT hybrid thin films for pseudocapacitive behaviors

We report facile synthesis of polydopamine-functionalized graphene oxide/conducting polymer hybrids as an electrode material for supercapacitors. Bio-inspired polydopamine has catechol moieties that can undergo redox transformation, which may result in extra faradic capacitance. Polydopamine-functionalized graphene oxide hybrid materials, which were easily prepared by concomitant dopamine oxidation and slight reduction of graphene oxide, showed enhanced specific capacitance when compared to bare graphene oxide hybrid materials. Although polydopamine layers slightly decreased the conductivity of the hybrid materials, extra redox reactions appeared to contribute more to the overall specific capacitance.

Preparation and properties of dopamine reduced graphene oxide and its composites of epoxy

ABSTRACTTo improve the thermal and mechanical properties and further to expand its applications of epoxy in electronic packaging, reduced graphene oxide/epoxy composites have been successfully prepared, in which dopamine (DA) was used as reducing agent and modifier for graphene oxide (GO) to avoid the environmentally harmful reducing agents and address the problem of aggregation of graphene in composites. Further studies revealed that DA could effectively eliminate the labile oxygen functionality of GO and generate polydopamine functionalized graphene oxide (PDA‐GO) because DA would be oxidated and undergo the rearrangement and intermolecular cross‐linking reaction to produce polydopamine (PDA), which would improve the interfacial adhesion between GO and epoxy, and further be beneficial for the homogenous dispersion of GO in epoxy matrix. The effect of PDA‐GO on the thermal and mechanical properties of PDA‐GO/epoxy composites was also investigated, and the incorporation of PDA‐GO could increase the thermal conductivity, storage modulus, glass transition (Tg), and dielectric constant of epoxy. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39754.