Effect of reduced graphene oxide (rGO) compaction degree and concentration on rGO-polymer composites printability and cell interactions

Graphene derivatives combined with polymers have attracted enormous attention for bone tissue engineering applications. Among others, reduced graphene oxide (rGO) is one of the preferred graphene-based fillers for the preparation of composites via melt compounding, and their further processing into 3D scaffolds, due to its established large-scale production method, thermal stability, and electrical conductivity. In this study, rGO (low bulk density 10g/L) was compacted by densification using a solvent (either acetone or water) prior to melt compounding, to simplify its handling and dosing into a twin-screw extrusion system. The effects of rGO bulk density (medium and high), densification solvent, and rGO concentration (3, 10 and 15% in weight) on rGO dispersion within the composite, electrical conductivity, printability and cell-material interactions were studied. High bulk density rGO (90 g/L) occupied a low volume fraction within polymer composites, offering poor electrical properties but a reproducible printability up to 15 wt% rGO. On the other hand, the volume fraction within the composites of medium bulk density rGO (50 g/L) was higher for a given concentration, enhancing rGO particle interactions and leading to enhanced electrical conductivity, but compromising the printability window. For a given bulk density (50 g/L), rGO densified in water was more compacted and offered poorer dispersability within the polymer than rGO densified in acetone, and resulted in scaffolds with poor layer bonding or even lack of printability at high rGO percentages. A balance in printability and electrical properties was obtained for composites with medium bulk density rGO densified in acetone. Here, increasing rGO concentration led to more hydrophilic composites with a noticeable increase in protein adsorption. Moreover, scaffolds prepared with such composites presented antimicrobial properties even at low rGO contents (3 wt%). In addition, the viability and proliferation of human mesenchymal stromal cells (hMSCs) was maintained on scaffolds with up to 15% rGO and with enhanced osteogenic differentiation on 3% rGO scaffolds.

Download Full-text

Manufacture and characterization of conductor-insulator composites based on carbon nanotubes and thermally reduced graphene oxide

Pure and Applied Chemistry ◽

10.1515/pac-2013-1207 ◽

2014 ◽

Vol 86 (5) ◽

pp. 765-774 ◽

Cited By ~ 13

Author(s):

Chris R. Bowen ◽

Sam Buschhorn ◽

Vana Adamaki

Keyword(s):

Graphene Oxide ◽

Electrical Properties ◽

Reduced Graphene Oxide ◽

Volume Fraction ◽

Epoxy Composites ◽

Frequency Dependent ◽

Reduced Graphene ◽

Electrical Conductivities ◽

Conductive Component

AbstractIn this paper we present characterization data for carbon nanotube (CNT)-epoxy and thermally reduced graphene oxide (TRGO)-epoxy nano-composites. The frequency-dependent ac conductivity and permittivity are examined as a function of volume fraction of carbon-based filler. The measured electrical properties and their frequency dependency are evaluated on the basis that such composites can be considered as a network of resistors and capacitors, whereby the resistors represent the conductive component (CNT or TRGO) and the capacitors are the insulating component (epoxy matrix). Differences observed between the frequency-dependent electrical properties of the CNT-epoxy and TRGO-epoxy composites are explained in terms of the different electrical conductivities of the CNT and TRGO phase.

Download Full-text

The correlation between electrical conductivity and second-order Raman modes of laser-reduced graphene oxide

Physical Chemistry Chemical Physics ◽

10.1039/c9cp00093c ◽

2019 ◽

Vol 21 (19) ◽

pp. 10125-10134 ◽

Cited By ~ 18

Author(s):

Bing Ma ◽

Raul D. Rodriguez ◽

Alexey Ruban ◽

Sergey Pavlov ◽

Evgeniya Sheremet

Keyword(s):

Electrical Conductivity ◽

Atomic Force Microscopy ◽

Graphene Oxide ◽

Electrical Properties ◽

Reduced Graphene Oxide ◽

Second Order ◽

Force Microscopy ◽

Atomic Force ◽

Reduced Graphene ◽

Raman Modes

Second-order Raman modes correlate with the electrical properties of reduced graphene oxide measured at the nanoscale by atomic force microscopy.

Download Full-text

Electrical conductivity of thermally reduced graphene oxide/polymer composites with a segregated structure

Carbon ◽

10.1016/j.carbon.2013.08.016 ◽

2013 ◽

Vol 65 ◽

pp. 371-373 ◽

Cited By ~ 71

Author(s):

Mengkai Li ◽

Chunxiao Gao ◽

Hongliang Hu ◽

Zhudi Zhao

Keyword(s):

Electrical Conductivity ◽

Graphene Oxide ◽

Polymer Composites ◽

Reduced Graphene Oxide ◽

Reduced Graphene ◽

Segregated Structure

Download Full-text

Graphene Oxide: A Smart (Starting) Material for Natural Methylxanthines Adsorption and Detection

Molecules ◽

10.3390/molecules24234247 ◽

2019 ◽

Vol 24 (23) ◽

pp. 4247 ◽

Cited By ~ 5

Author(s):

Rita Petrucci ◽

Isabella Chiarotto ◽

Leonardo Mattiello ◽

Daniele Passeri ◽

Marco Rossi ◽

...

Keyword(s):

Electrical Conductivity ◽

Graphene Oxide ◽

Nucleic Acids ◽

Reduced Graphene Oxide ◽

Electrochemical Sensors ◽

Enzymatic Digestion ◽

Biologically Active ◽

Polar Solvents ◽

Dna And Rna ◽

Reduced Graphene

Natural methylxanthines, caffeine, theophylline and theobromine, are widespread biologically active alkaloids in human nutrition, found mainly in beverages (coffee, tea, cocoa, energy drinks, etc.). Their detection is thus of extreme importance, and many studies are devoted to this topic. During the last decade, graphene oxide (GO) and reduced graphene oxide (RGO) gained popularity as constituents of sensors (chemical, electrochemical and biosensors) for methylxanthines. The main advantages of GO and RGO with respect to graphene are the easiness and cheapness of synthesis, the notable higher solubility in polar solvents (water, among others), and the higher reactivity towards these targets (mainly due to – interactions); one of the main disadvantages is the lower electrical conductivity, especially when using them in electrochemical sensors. Nonetheless, their use in sensors is becoming more and more common, with the obtainment of very good results in terms of selectivity and sensitivity (up to 5.4 × 10−10 mol L−1 and 1.8 × 10−9 mol L−1 for caffeine and theophylline, respectively). Moreover, the ability of GO to protect DNA and RNA from enzymatic digestion renders it one of the best candidates for biosensors based on these nucleic acids. This is an up-to-date review of the use of GO and RGO in sensors.

Download Full-text

High dielectric polymer composites from thermal-induced in-situ formation of conjugated structures and reduced graphene oxide

Materials Chemistry and Physics ◽

10.1016/j.matchemphys.2021.124276 ◽

2021 ◽

Vol 262 ◽

pp. 124276

Author(s):

Zewei Zhu ◽

Yingbo Liu ◽

Junqi Ge ◽

Zhaoyu Hu ◽

Gaorong Zeng ◽

...

Keyword(s):

Graphene Oxide ◽

Polymer Composites ◽

Reduced Graphene Oxide ◽

Reduced Graphene ◽

In Situ Formation ◽

High Dielectric ◽

Dielectric Polymer

Download Full-text

Elastomer based nanocomposites with reduced graphene oxide nanofillers allow for enhanced tensile and electrical properties

Journal of Polymer Research ◽

10.1007/s10965-020-2039-3 ◽

2020 ◽

Vol 27 (5) ◽

Author(s):

Sumaira Mazhar ◽

Bret P. Lawson ◽

Barry D. Stein ◽

Maren Pink ◽

John Carini ◽

...

Keyword(s):

Graphene Oxide ◽

Electrical Properties ◽

Reduced Graphene Oxide ◽

Reduced Graphene

Download Full-text

Nanoporous Reduced Graphene Oxide and Polymer Composites as Efficient Counter Electrodes in Dye-Sensitized Solar Cells

ACS Applied Electronic Materials ◽

10.1021/acsaelm.9b00593 ◽

2020 ◽

Vol 2 (3) ◽

pp. 626-634 ◽

Cited By ~ 2

Author(s):

Vediappan Sudhakar ◽

Anup Kumar Singh ◽

Mrinmoy Kumar Chini

Keyword(s):

Graphene Oxide ◽

Solar Cells ◽

Polymer Composites ◽

Reduced Graphene Oxide ◽

Dye Sensitized Solar Cells ◽

Counter Electrodes ◽

Dye Sensitized ◽

Reduced Graphene ◽

Sensitized Solar Cells

Download Full-text

Chemically reduced graphene oxide-coated knitted fabric imparted conductivity and outstanding hydrophobicity

Textile Research Journal ◽

10.1177/0040517521995471 ◽

2021 ◽

pp. 004051752199547

Author(s):

Min Hou ◽

Xinghua Hong ◽

Yanjun Tang ◽

Zimin Jin ◽

Chengyan Zhu ◽

...

Keyword(s):

Electrical Conductivity ◽

Graphene Oxide ◽

Reduced Graphene Oxide ◽

Chemical Reduction ◽

Knitted Fabric ◽

Mesh Structure ◽

Reduced Graphene ◽

Chemically Reduced Graphene Oxide ◽

Modified Hummers Method

Functionalized knitted fabric, as a kind of flexible, wearable, and waterproof material capable of conductivity, sensitivity and outstanding hydrophobicity, is valuable for multi-field applications. Herein, the reduced graphene oxide (RGO)-coated knitted fabric (polyester/spandex blended) is prepared, which involves the use of graphite oxide (GO) by modified Hummers method and in-situ chemical reduction with hydrazine hydrate. The treated fabric exhibits a high electrical conductivity (202.09 S/cm) and an outstanding hydrophobicity (140°). The outstanding hydrophobicity is associated with the morphology of the fabric and fiber with reference to pseudo-infiltration. These properties can withstand repeated bending and washing without serious deterioration, maintaining good electrical conductivity (35.70 S/cm) and contact angle (119.39°) after eight standard washing cycles. The material, which has RGO architecture and continuous loop mesh structure, can find wide use in smart garment applications.

Download Full-text