UF membrane with highly improved flux by hydrophilic network between graphene oxide and brominated poly(2,6-dimethyl-1,4-phenylene oxide)

2014 ◽  
Vol 2 (43) ◽  
pp. 18562-18573 ◽  
Author(s):  
Lijia Yang ◽  
Beibei Tang ◽  
Peiyi Wu
Keyword(s):  
Graphene Oxide ◽  
Rough Surfaces ◽  
Cross Linking ◽  
Phenylene Oxide ◽  
Hydrophilic Network

PEI–GO/BPPO membranes with highly rough surfaces and hydrophilic cross-linking networks are formed by PEI–GO covalent bonded with BPPO.

scholarly journals Hyperbranched polyamide modified graphene oxide-reinforced polyurethane nanocomposites with enhanced mechanical properties

RSC Advances ◽  
2021 ◽  
Vol 11 (24) ◽  
pp. 14484-14494
Author(s):  
Yahao Liu ◽  
Jian Zheng ◽  
Xiao Zhang ◽  
Yongqiang Du ◽  
Guibo Yu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
High Performance ◽  
Cross Linking ◽  
Elongation At Break ◽  
Modified Graphene Oxide ◽  
High Performance Composite ◽  
Modified Graphene ◽  
Polyurethane Nanocomposites ◽  
Hyperbranched Polyamide

We successfully modified graphene oxide with amino-terminated hyperbranched polyamide (HGO), and obtained a high-performance composite with enhanced strength and elongation at break via cross-linking hydroxyl-terminated polybutadiene chains with HGO.

scholarly journals Enhanced antibacterial activity through the controlled alignment of graphene oxide nanosheets

2017 ◽  
Vol 114 (46) ◽  
pp. E9793-E9801 ◽  
Author(s):  
Xinglin Lu ◽  
Xunda Feng ◽  
Jay R. Werber ◽  
Chiheng Chu ◽  
Ines Zucker ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Antibacterial Activity ◽  
Graphene Oxide ◽  
Direct Electron Transfer ◽  
Composite Films ◽  
Experimental Studies ◽  
Cross Linking ◽  
Vertical Orientation ◽  
Electron Transfer Mechanism ◽  
Vertically Aligned

The cytotoxicity of 2D graphene-based nanomaterials (GBNs) is highly important for engineered applications and environmental health. However, the isotropic orientation of GBNs, most notably graphene oxide (GO), in previous experimental studies obscured the interpretation of cytotoxic contributions of nanosheet edges. Here, we investigate the orientation-dependent interaction of GBNs with bacteria using GO composite films. To produce the films, GO nanosheets are aligned in a magnetic field, immobilized by cross-linking of the surrounding matrix, and exposed on the surface through oxidative etching. Characterization by small-angle X-ray scattering and atomic force microscopy confirms that GO nanosheets align progressively well with increasing magnetic field strength and that the alignment is effectively preserved by cross-linking. When contacted with the model bacteriumEscherichia coli, GO nanosheets with vertical orientation exhibit enhanced antibacterial activity compared with random and horizontal orientations. Further characterization is performed to explain the enhanced antibacterial activity of the film with vertically aligned GO. Using phospholipid vesicles as a model system, we observe that GO nanosheets induce physical disruption of the lipid bilayer. Additionally, we find substantial GO-induced oxidation of glutathione, a model intracellular antioxidant, paired with limited generation of reactive oxygen species, suggesting that oxidation occurs through a direct electron-transfer mechanism. These physical and chemical mechanisms both require nanosheet penetration of the cell membrane, suggesting that the enhanced antibacterial activity of the film with vertically aligned GO stems from an increased density of edges with a preferential orientation for membrane disruption. The importance of nanosheet penetration for cytotoxicity has direct implications for the design of engineering surfaces using GBNs.

scholarly journals Chemically Cross-Linked Graphene Oxide as a Selective Layer on Electrospun Polyvinyl Alcohol Nanofiber Membrane for Nanofiltration Application

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2867
Author(s):  
Myoung Jun Park ◽  
Grace M. Nisola ◽  
Dong Han Seo ◽  
Chen Wang ◽  
Sherub Phuntsho ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Polyvinyl Alcohol ◽  
Self Assembly ◽  
Water Flux ◽  
Composite Membranes ◽  
Cross Linking ◽  
Support Surface ◽  
Eosin Y ◽  
Selective Layer ◽  
Assembly Technique

Graphene oxide (GO) nanosheets were utilized as a selective layer on a highly porous polyvinyl alcohol (PVA) nanofiber support via a pressure-assisted self-assembly technique to synthesize composite nanofiltration membranes. The GO layer was rendered stable by cross-linking the nanosheets (GO-to-GO) and by linking them onto the support surface (GO-to-PVA) using glutaraldehyde (GA). The amounts of GO and GA deposited on the PVA substrate were varied to determine the optimum nanofiltration membrane both in terms of water flux and salt rejection performances. The successful GA cross-linking of GO interlayers and GO-PVA via acetalization was confirmed by FTIR and XPS analyses, which corroborated with other characterization results from contact angle and zeta potential measurements. Morphologies of the most effective membrane (CGOPVA-50) featured a defect-free GA cross-linked GO layer with a thickness of ~67 nm. The best solute rejections of the CGOPVA-50 membrane were 91.01% for Na2SO4 (20 mM), 98.12% for Eosin Y (10 mg/L), 76.92% for Methylene blue (10 mg/L), and 49.62% for NaCl (20 mM). These findings may provide one of the promising approaches in synthesizing mechanically stable GO-based thin-film composite membranes that are effective for solute separation via nanofiltration.

scholarly journals Cross-Linking With Diamine Monomers to Prepare Graphene Oxide Composite Membranes With Varying D-Spacing for Enhanced Desalination Properties

2021 ◽  
Vol 9 ◽  
Author(s):  
Hong Ju ◽  
Jinzhuo Duan ◽  
Haitong Lu ◽  
Weihui Xu
Keyword(s):  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Water Flux ◽  
Covalent Bond ◽  
Composite Membranes ◽  
Rejection Rate ◽  
High Water ◽  
Cross Linking ◽  
Separation Performance ◽  
X Ray

As a new type of membrane material, graphene oxide (GO) can easily form sub-nanometer interlayer channels, which can effectively screen salt ions. The composite membrane and structure with a high water flux and good ion rejection rate were compared by the cross-linking of GO with three different diamine monomers: ethylenediamine (EDA), urea (UR), and p-phenylenediamine (PPD). X-ray photoelectron spectroscopy (XPS) results showed that unmodified GO mainly comprises π-π interactions and hydrogen bonds, but after crosslinking with diamine, both GO and mixed cellulose (MCE) membranes are chemically bonded to the diamine. The GO-UR/MCE membrane achieved a water flux similar to the original GO membrane, while the water flux of GO-PPD/MCE and GO-EDA/MCE dropped. X-ray diffraction results demonstrated that the covalent bond between GO and diamine can effectively inhibit the extension of d-spacing during the transition between dry and wet states. The separation performance of the GO-UR/MCE membrane was the best. GO-PPD/MCE had the largest contact angle and the worst hydrophilicity, but its water flux was still greater than GO-EDA/MCE. This result indicated that the introduction of different functional groups during the diamine monomer cross-linking of GO caused some changes in the performance structure of the membrane.

Preparation of Stable Hydrophilic Polyethyleneimine Cross-Linked Graphene Oxide/Titanium Dioxide Membranes for Dye Separation

NANO ◽  
2021 ◽  
pp. 2150008
Author(s):  
Hongwei Liu ◽  
Jinhua Liu ◽  
Jun Li ◽  
Zhanchao Liu ◽  
Weifu Wu ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Titanium Dioxide ◽  
Graphene Oxide ◽  
Water Flux ◽  
Cross Linking ◽  
Sunset Yellow ◽  
Water Contact ◽  
Static Water ◽  
The Cross ◽  
The Stability

An excellent novel laminar and hierarchical polyethyleneimine cross-linked graphene oxide/titanium dioxide (GO–TiO2–PEI) membrane was successfully prepared by vacuum filtration technology using polyethyleneimine (PEI) as the cross-linking agent and a GO–TiO2 nanocomposite as the substrate. The resultant membrane (GO–TiO2–PEI) displayed a favorable antifouling performance with bovine serum albumin (BSA) and showed good hydrophilicity and wettability, with a static water contact angle of 13.2∘. The stability of the GO–TiO2–PEI membrane in aqueous solution obviously improved with the cross-linking of PEI compared with that of the GO and GO–TiO2 membranes. The GO–TiO2–PEI membrane also exhibited a satisfactory water flux of 48.6[Formula: see text]L m[Formula: see text] h[Formula: see text] bar[Formula: see text]. The GO–TiO2–PEI membrane exhibited a good performance for effectively separating different dyes including methylene blue (MB), rhodamine B (RB), methyl orange (MO), sunset yellow (SY), new coccine (NC) and amaranth. All the above results suggested that the GO–TiO2–PEI membrane could be used as an excellent stable hydrophilic membrane for efficiently separating dyes from aqueous solution.

Injectable and mechanically robust 4-arm PPO–PEO/graphene oxide composite hydrogels for biomedical applications

2015 ◽  
Vol 51 (42) ◽  
pp. 8876-8879 ◽  
Author(s):  
Yunki Lee ◽  
Jin Woo Bae ◽  
Thai Thanh Hoang Thi ◽  
Kyung Min Park ◽  
Ki Dong Park
Keyword(s):  
Graphene Oxide ◽  
Biomedical Applications ◽  
Cross Linking ◽  
Oxide Composite ◽  
Composite Hydrogels

Graphene-based nanomaterials with different oxidation degrees were incorporated into Tetronic–tyramine (Tet–TA) hydrogels via enzymatic cross-linking.

Reduction versus cross-linking: how to improve the tensile strength of graphene oxide/polyvinyl alcohol composite film

2017 ◽  
Vol 4 (8) ◽  
pp. 085601 ◽  
Author(s):  
Cheng-an Tao ◽  
Hao Zhang ◽  
Jian Huang ◽  
Xiaorong Zou ◽  
Hui Zhu ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Graphene Oxide ◽  
Polyvinyl Alcohol ◽  
Composite Film ◽  
Cross Linking
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