scholarly journals Polyethersulfone/Graphene Oxide Ultrafiltration Membranes from Solutions in Ionic Liquid

MRS Advances ◽  
2017 ◽  
Vol 2 (46) ◽  
pp. 2505-2511 ◽  
Author(s):  
Dinesh. K. Mahalingam ◽  
DooLi. Kim ◽  
Suzana. P. Nunes
Keyword(s):  
Graphene Oxide ◽  
Dimethyl Formamide ◽  
High Flux ◽  
Ultrafiltration Membranes ◽  
Cross Sectional ◽  
Selective Layer ◽  
Trade Off ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Microscopy Images

ABSTRACTNovel high flux polyethersulfone (PES) ultrafiltration membranes were fabricated by incorporating different amounts of graphene oxide (GO) sheets to PES as nanofillers. The membranes were prepared from solutions in 50/50 1-ethyl-3-methylimidazolium-diethylphosphate/N,N-dimethyl formamide. It was observed that the water permeance increased from 550 to 800 L m-2h-1bar-1, with incorporation of 1 wt% GO, keeping a molecular weight cut-off (MWCO) of approximately 32-34 kg mol-1. Cross-sectional scanning electron microscopy images of GO/PES membranes showed the formation of ultrathin selective layer unlike pristine membranes. Contact angle measurements confirmed the increase of hydrophilicity, by increasing the GO concentration. The rejection of humic acid and bovine serum albumin was demonstrated. The mechanical properties were improved, compared with the pristine membranes. The performance was just above the trade-off relationship between permeance and separation factor for PES membranes reported in the literature.

Reinforcement of nanostructured reduced graphene oxide: a facile approach to develop high-performance nanocomposite ultrafiltration membranes minimizing the trade-off between flux and selectivity

RSC Advances ◽  
2015 ◽  
Vol 5 (58) ◽  
pp. 46801-46816 ◽  
Author(s):  
Avishek Pal ◽  
Soumitra Kar ◽  
A. K. Debnath ◽  
D. K. Aswal ◽  
R. C. Bindal ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
High Performance ◽  
Mechanical Stability ◽  
Ultrafiltration Membranes ◽  
Trade Off ◽  
Reduced Graphene ◽  
Uf Membranes

In situ impregnation of nanostructured reduced graphene oxide (nRGO) in Ps matrix leads to Ps–nRGO composite UF membranes with promising attributes such as improved flux, optimum selectivity along with reasonable thermal and mechanical stability.

Nanotubes Growth on Ti-15Mo Alloys by Anodization at Low Voltage

2016 ◽  
Vol 869 ◽  
pp. 924-929 ◽  
Author(s):  
André Luiz Reis Rangel ◽  
Guilherme Rogeri Moreira Santos ◽  
Ana Paula Rosifini Alves Claro
Keyword(s):  
Positive Characteristic ◽  
Low Voltage ◽  
Ammonium Fluoride ◽  
X Ray Diffraction ◽  
X Ray ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Biological Environment ◽  
Post Implantation ◽  
Microscopy Images

Surface modification by nanotubes growth is an efficient technique to improve the interaction between implant and biological environment. Several studies indicate who low voltages anodizations are able to generate nanotubes with smaller diameters, positive characteristic for the post-implantation cell growth. The aim of this study was to characterize the morphology of the nanotubes formed on Ti-15Mo surfaces applying 5 or 10 V as anodizing voltage. For both conditions were used glycerol based electrolyte with ammonium fluoride and the anodization time was 24 hours. The samples were cleaned in an ultrasonic bath and annealed at 450 ° for 1 hour after anodization. In order to characterize the surfaces were performed scanning electron microscopy images, contact angle measurements and X-ray diffraction analysis. The results confirmed the formation of nanotubes evenly distributed on the surfaces and a direct relation between anodizing voltage and nanotubes diameters.

scholarly journals A Comparison of Commercial and Experimental Ultrafiltration Membranes via Surface Property Analysis and Fouling Tests

2006 ◽  
Vol 41 (1) ◽  
pp. 84-93 ◽  
Author(s):  
Huyen T. Dang ◽  
Roberto M. Narbaitz ◽  
Takeshi Matsuura ◽  
Kailash C. Khulbe
Keyword(s):  
Ultrafiltration Membranes ◽  
Force Microscopy ◽  
Ottawa River ◽  
Angle Measurements ◽  
Atomic Force ◽  
Molecular Weight Cutoff ◽  
Contact Angle Measurements ◽  
Different Types ◽  
Transport Analysis ◽  
Surface Modified

Abstract Surface modified polyethersulfone (PES) membranes via the addition of different hydrophiLic Surface Modifying Macromolecules (LSMMs) have been developed by Matsuura, Narbaitz and co-workers. This study compares the performance of the best PES-LSMM membrane with nine commercial ultrafiltration membranes manufactured using five different types of base polymers (polyethersulfone, polysulfone, celluloseacetate, polyacrylonitrile and cellulose) in the same range of molecular weight cutoff (MWCO) (from 40 to 120 kDal). All membranes were characterized by using atomic force microscopy, contact angle measurements, solute transport analysis and then evaluated through fouling tests with Ottawa River water (ORW). While PES-LSMM membranes had much lower initial flux than the commercial membranes, they had the highest total organic carbon (TOC) rejection (80%) and the lowest flux reduction (62%). For the commercial membranes, the range of TOC rejections and flux reductions were 62 to 80% and 68 to 80%, respectively. Given their high TOC rejection and relatively high foulant deposition, fouling of the PES-LSMM membranes appears to be controlled by a surface gel.

scholarly journals Synthesis and Characterization of Electrospun Composite Scaffolds Based on Chitosan-Carboxylated Graphene Oxide with Potential Biomedical Applications

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2535
Author(s):  
Elena Cojocaru ◽  
Jana Ghitman ◽  
Elena Iuliana Biru ◽  
Gratiela Gradisteanu Pircalabioru ◽  
Eugeniu Vasile ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Cellular Proliferation ◽  
Biological Properties ◽  
Synthesis Process ◽  
Composite Scaffolds ◽  
Angle Measurements ◽  
Nanofibrous Scaffolds ◽  
Contact Angle Measurements ◽  
Poly Ethylene

This research study reports the development of chitosan/carboxylated graphene oxide (CS/GO-COOH) composite scaffolds with nanofibrous architecture using the electrospinning method. The concept of designed composite fibrous material is based on bringing together the biological properties of CS, mechanical, electrical, and biological characteristics of GO-COOH with the versatility and efficiency of ultra-modern electrospinning techniques. Three different concentrations of GO-COOH were added into a chitosan (CS)-poly(ethylene oxide) (PEO) solution (the ratio between CS/PEO was 3/7 (w/w)) and were used in the synthesis process of composite scaffolds. The effect of GO-COOH concentration on the spinnability, morphological and mechanical features, wettability, and biological properties of engineered fibrous scaffolds was thoroughly investigated. FTIR results revealed the non-covalent and covalent interactions that could take place between the system’s components. The SEM micrographs highlighted the nanofibrous architecture of scaffolds, and the presence of GO-COOH sheets along the composite CS/GO-COOH nanofibers. The size distribution graphs showed a decreasing trend in the mean diameter of composite nanofibers with the increase in GO-COOH content, from 141.40 nm for CS/PG 0.1% to 119.88 nm for CS/PG 0.5%. The dispersion of GO-COOH led to composite scaffolds with increased elasticity; the Young’s modulus of CS/PG 0.5% (84 ± 4.71 MPa) was 7.5-fold lower as compared to CS/PEO (662 ± 15.18 MPa, p < 0.0001). Contact angle measurements showed that both GO-COOH content and crosslinking step influenced the surface wettability of scaffolds, leading to materials with ~1.25-fold higher hydrophobicity. The in vitro cytocompatibility assessment showed that the designed nanofibrous scaffolds showed a reasonable cellular proliferation level after 72 h of contact with the fibroblast cells.

scholarly journals Development and Characterization of a Poly (Vinyl Alcohol)/Graphene Oxide Composite Hydrogel as An Artificial Cartilage Material

2018 ◽  
Vol 8 (11) ◽  
pp. 2272 ◽  
Author(s):  
Yibo Zhao ◽  
Wataru Terai ◽  
Yuko Hoshijima ◽  
Kazuma Gotoh ◽  
Koji Matsuura ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Vinyl Alcohol ◽  
Cell Attachment ◽  
Tensile Tests ◽  
Composite Hydrogel ◽  
Poly Vinyl Alcohol ◽  
Sem Images ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Surface Contact Angle

Poly (vinyl alcohol) hydrogel (PVA-H) is expected to be a suitable artificial articular cartilage material because of its high biocompatibility. However, it is difficult to affix to the surface of a living joint because it is bioinert and its mechanical strength needs to be improved. In this study, graphene oxide (GO) subjected to two oxidation rounds was used to form a nanocomposite material and the composite hydrogel PVA-GO-H was prepared by low-temperature crystallization. Scanning electron microscope (SEM) images showed that the addition of GO can increase roughness of the hydrogel surface. Contact angle measurements showed that the surface of PVA-GO-H exhibited hydrophobicity that increased with GO concentration and not with that of PVA-H, indicating that the hydrophilic parts of PVA and GO form hydrogen bonds and the hydrophobic part of GO was exposed on the surface. Tensile tests demonstrated that Young’s modulus was enhanced on the addition of GO. Osteoblast cells showed more affinity for PVA-GO-H than PVA-H, which much more cells adhere to than to PVA-GO-H after a certain period of culturing, suggesting GO can improve the cell attachment of PVA-H. Further studies on the influence of the oxidation time of GO are still required.

Nanostructured Polymer Brushes With Reversibly Changing Properties

2002 ◽  
Vol 727 ◽  
Author(s):  
Denys Usov ◽  
Manfred Stamm ◽  
Sergiy Minko ◽  
Christian Froeck ◽  
Andreas Scholl ◽  
...  
Keyword(s):  
Polymer Brushes ◽  
Phase Segregation ◽  
Water Contact ◽  
Angle Measurements ◽  
Nanostructured Polymer ◽  
Contact Angle Measurements ◽  
Vertical Segregation ◽  
Oxygen Plasma Etching ◽  
Grafting From ◽  
Photoemission Electron

AbstractWe investigated the interplay between different mechanisms of the lateral and vertical segregation in the synthesized via “grafting from” approach symmetric A/B (where A and B are poly(styrene-co-2,3,4,5,6-pentafluorostyrene) and poly(methylmethacrylate), respectively) polymer brushes upon exposure to different solvents. We used X-ray photoemission electron spectroscopy and microscopy (X-PEEM), AFM, water contact angle measurements, and oxygen plasma etching to study morphology of the brushes. The ripple morphology after toluene (nonselective solvent) revealed elongated lamellar-like domains of A and B polymers alternating across the surface. The dimple-A morphology consisting of round clusters of the polymer A was observed after acetone (selective solvent for B). The top layer was enriched with the polymer B showing that the brush underwent both the lateral and vertical phase segregation. A qualitative agreement with predictions of SCF theory was found.

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