scholarly journals Hydroplastic foaming of graphene aerogels and artificially intelligent tactile sensors

2020 ◽  
Vol 6 (46) ◽  
pp. eabd4045
Author(s):  
Kai Pang ◽  
Xian Song ◽  
Zhen Xu ◽  
Xiaoting Liu ◽  
Yingjun Liu ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Mechanical Stability ◽  
Bubble Formation ◽  
Tactile Sensors ◽  
Graphene Aerogel ◽  
Precision Control ◽  
Direct Foaming ◽  
Graphene Aerogels ◽  
Cellular Wall ◽  
The Ideal

Direct foaming from solids is the most efficient method to fabricate porous materials. However, the ideal foaming fails to prepare aerogel of nanoparticles because the plasticity of their solids is denied by the overwhelming interface interactions. Here, we invent a hydroplastic foaming method to directly convert graphene oxide solids into aerogel bulks and microarrays, replacing the prevalent freezing method. The water intercalation plasticizes graphene oxide solids and enables direct foaming instead of catastrophic fragmentation. The bubble formation follows a general crystallization rule and allows nanometer-precision control of cellular wall thickness down to 8 nm. Bubble clustering generates hyperboloid structures with seamless basal connection and renders graphene aerogels with ultrarobust mechanical stability against extreme deformations. We exploit graphene aerogel to fabricate tactile microarray sensors with ultrasensitivity and ultrastability, achieving a high accuracy (80%) in artificially intelligent touch identification that outperforms human fingers (30%).

Tuning the aggregation of graphene oxide dispersions to synthesize elastic, low density graphene aerogels

2017 ◽  
Vol 5 (44) ◽  
pp. 23123-23130 ◽  
Author(s):  
Kaiwen Hu ◽  
Thomas Szkopek ◽  
Marta Cerruti
Keyword(s):  
Graphene Oxide ◽  
Low Density ◽  
Graphene Aerogel ◽  
Graphene Aerogels

Controlled aggregation of graphene oxide leads to the formation of ultralight elastic graphene aerogel.

Bio-based graphene/sodium alginate aerogels for strain sensors

RSC Advances ◽  
2016 ◽  
Vol 6 (68) ◽  
pp. 64056-64064 ◽  
Author(s):  
Xue Yuan ◽  
Yong Wei ◽  
Song Chen ◽  
Pingping Wang ◽  
Lan Liu
Keyword(s):  
Graphene Oxide ◽  
Sodium Alginate ◽  
Mechanical Stability ◽  
High Sensitivity ◽  
Strain Sensors ◽  
Graphene Aerogels

Bio-based graphene aerogels are fabricated with graphene oxide and sodium alginate, showing great potential in flexible strain sensors due to the excellent mechanical stability and high sensitivity to compression and bending deformations.

scholarly journals Graphene Aerogel Growth on Functionalized Carbon Fibers

Molecules ◽  
2020 ◽  
Vol 25 (6) ◽  
pp. 1295 ◽  
Author(s):  
Katerina Vrettos ◽  
Konstantinos Spyrou ◽  
Vasilios Georgakilas
Keyword(s):  
Electrical Conductivity ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Carbon Fibers ◽  
Mechanical Stability ◽  
High Surface ◽  
Graphene Aerogel ◽  
Mechanical Reinforcement ◽  
Reduced Graphene ◽  
Aerogel Composite

Graphene aerogel (GA) is a lightweight, porous, environmentally friendly, 3D structured material with interesting properties, such as electrical conductivity, a high surface area, and chemical stability, which make it a powerful tool in energy storage, sensing, catalyst support, or environmental applications. However, the poor mechanical stability that often characterizes graphene aerogels is a serious obstacle for their use in such applications. Therefore, we report here the successful mechanical reinforcement of GA with carbon fibers (CFs) by combining reduced graphene oxide (rGO) and CFs in a composite material. The surfaces of the CFs were first successfully desized and enriched with epoxy groups using epichloridrine. Epoxy-functionalized CFs (epoxy-CFs) were further covered by reduced graphene oxide (rGO) nanosheets, using triethylene tetramine (TETA) as a linker. The rGO-covered CFs were finally incorporated into the GA, affording a stiff monolithic aerogel composite. The as-prepared epoxy-CF-reinforced GA was characterized by spectroscopic and microscopic techniques and showed enhanced electrical conductivity and compressive strength. The improved electrical and mechanical properties of the GA-CFs composite could be used, among other things, as electrode material or strain sensor applications.

Three-dimensional MoSx(1 < x < 2) nanosheets decorated graphene aerogel for lithium–oxygen batteries

2016 ◽  
Vol 4 (28) ◽  
pp. 10986-10991 ◽  
Author(s):  
Liangyu Li ◽  
Chunguang Chen ◽  
Junming Su ◽  
Peng Kuang ◽  
Congcong Zhang ◽  
...  
Keyword(s):  
Freeze Drying ◽  
Three Dimensional ◽  
Drying Method ◽  
Graphene Aerogel ◽  
Graphene Aerogels ◽  
3D Architecture ◽  
Lithium Oxygen Batteries ◽  
Potential Oxygen ◽  
Oxygen Cathode

MoSx/graphene aerogels with a 3D architecture were synthesized using a hydrothermal and freeze-drying method and were further applied in Li–O2batteries as a potential oxygen cathode.

scholarly journals Graphene Oxide-Embedded Extracellular Matrix- Derived Hydrogel as a Multiresponsive Platform for 3D Bioprinting Applications

2021 ◽  
Vol 7 (3) ◽  
Author(s):  
Laura Rueda-Gensini ◽  
Julian A Serna ◽  
Javier Cifuentes ◽  
Juan C Cruz ◽  
Carolina Muñoz-Camargo
Keyword(s):  
Graphene Oxide ◽  
Mechanical Stability ◽  
Light Exposure ◽  
Structural Characteristics ◽  
Elastic Response ◽  
Cellular Interaction ◽  
3D Bioprinting ◽  
In Situ Reduction ◽  
Crosslinking Degree

Decellularized extracellular matrices (dECMs) have shown enormous potential for the biofabrication of tissues due to their biomimetic properties that promote enhanced cellular interaction and tissue regeneration. However, biofabrication schemes requiring electrostimulation pose an additional constraint due to the insulating properties of natural materials. Here, we propose a methacryloyl-modified decellularized small intestine submucosa (SISMA) hydrogel, embedded with graphene oxide (GO) nanosheets, for extrusion-based 3D bioprinting applications that require electrostimulation. Methacryloyl biochemicalmodification is performed to enhance the mechanical stability of dECM constructs by mediating photo-crosslinking reactions, and a multistep fabrication scheme is proposed to harness the bioactive and hydrophilic properties of GO and electroconductive properties of reduced GO. For this, GO was initially dispersed in SISMA hydrogels by exploiting its hydrophilicity and protein adsorption capabilities, and in situ reduction was subsequently performed to confer electroconductive abilities. SISMA-GO composite hydrogels were successfully prepared with enhanced structural characteristics, as shown by the higher crosslinking degree and increased elastic response upon blue-light exposure. Moreover, GO was homogeneously dispersed without affecting photocrosslinking reactions and hydrogel shear-thinning properties. Human adipose-derived mesenchymal stem cells were successfully bioprinted in SISMA-GO with high cell viability after 1 week and in situ reduction of GO during this period enhanced the electrical conductivity of these nanostructures. This work demonstrates the potential of SISMA-GO bioinks as bioactive and electroconductive scaffolds for electrostimulation applications in tissue engineering and regenerative medicine.

CNT-enhanced amino-functionalized graphene aerogel adsorbent for highly efficient removal of formaldehyde

2017 ◽  
Vol 41 (7) ◽  
pp. 2527-2533 ◽  
Author(s):  
Lirui Wu ◽  
Ziyi Qin ◽  
Lanxin Zhang ◽  
Tao Meng ◽  
Fei Yu ◽  
...  
Keyword(s):  
Functionalized Graphene ◽  
Efficient Removal ◽  
Graphene Aerogel ◽  
Graphene Aerogels ◽  
Highly Efficient ◽  
Gaseous Formaldehyde

Graphene aerogels modified using two different methods were investigated for their capacities to adsorb gaseous formaldehyde.

scholarly journals Graphene Oxide Oxygen Content Affects Physical and Biological Properties of Scaffolds Based on Chitosan/Graphene Oxide Conjugates

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1142 ◽  
Author(s):  
Iolanda Francolini ◽  
Elena Perugini ◽  
Ilaria Silvestro ◽  
Mariangela Lopreiato ◽  
Anna Scotto d’Abusco ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Mechanical Strength ◽  
Oxygen Content ◽  
Mechanical Stability ◽  
Biological Properties ◽  
Dermal Fibroblasts ◽  
Porous Scaffolds ◽  
Low Oxygen ◽  
Interdisciplinary Field

Tissue engineering is a highly interdisciplinary field of medicine aiming at regenerating damaged tissues by combining cells with porous scaffolds materials. Scaffolds are templates for tissue regeneration and should ensure suitable cell adhesion and mechanical stability throughout the application period. Chitosan (CS) is a biocompatible polymer highly investigated for scaffold preparation but suffers from poor mechanical strength. In this study, graphene oxide (GO) was conjugated to chitosan at two weight ratios 0.3% and 1%, and the resulting conjugates were used to prepare composite scaffolds with improved mechanical strength. To study the effect of GO oxidation degree on scaffold mechanical and biological properties, GO samples at two different oxygen contents were employed. The obtained GO/CS scaffolds were highly porous and showed good swelling in water, though to a lesser extent than pure CS scaffold. In contrast, GO increased scaffold thermal stability and mechanical strength with respect to pure CS, especially when the GO at low oxygen content was used. The scaffold in vitro cytocompatibility using human primary dermal fibroblasts was also affected by the type of used GO. Specifically, the GO with less content of oxygen provided the scaffold with the best biocompatibility.

scholarly journals Polyvinylamine Membranes Containing Graphene-Based Nanofillers for Carbon Capture Applications

Membranes ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 119 ◽  
Author(s):  
Casadei ◽  
Venturi ◽  
Giacinti Baschetti ◽  
Giorgini ◽  
Maccaferri ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Carbon Capture ◽  
Mechanical Stability ◽  
Composite Membranes ◽  
Sem Analysis ◽  
Gas Permeation ◽  
Separation Performance ◽  
Low Grade ◽  
Atr Spectroscopy ◽  
Few Layer Graphene

In the present study, the separation performance of new self-standing polyvinylamine (PVAm) membranes loaded with few-layer graphene (G) and graphene oxide (GO) was evaluated, in view of their use in carbon capture applications. PVAm, provided by BASF as commercial product named LupaminTM, was purified obtaining PVAm films with two degrees of purification: Low Grade (PVAm-LG) and High Grade (PVAm-HG). These two-grade purified PVAm were loaded with 3 wt% of graphene and graphene oxide to improve mechanical stability: indeed, pristine tested materials proved to be brittle when dry, while highly susceptible to swelling in humid conditions. Purification performances were assessed through FTIR-ATR spectroscopy, DSC and TGA analysis, which were carried out to characterize the pristine polymer and its nanocomposites. In addition, the membranes′ fracture surfaces were observed through SEM analysis to evaluate the degree of dispersion. Water sorption and gas permeation tests were performed at 35 °C at different relative humidity (RH), ranging from 50% to 95%. Overall, composite membranes showed improved mechanical stability at high humidity, and higher glass transition temperature (Tg) with respect to neat PVAm. Ideal CO2/N2 selectivity up to 80 was measured, paired with a CO2 permeability of 70 Barrer. The membranes’ increased mechanical stability against swelling, even at high RH, without the need of any crosslinking, represents an interesting result in view of possible further development of new types of facilitated transport composite membranes.

Recyclable catalyst for catalytic hydrogenation of phenylacetylene by coupling Pd nanoparticles with highly compressible graphene aerogels

RSC Advances ◽  
2014 ◽  
Vol 4 (104) ◽  
pp. 59977-59980 ◽  
Author(s):  
Xu Zhang ◽  
Zhiyu Wang ◽  
Shuang Li ◽  
Chunlei Wang ◽  
Jieshan Qiu
Keyword(s):  
Graphene Oxide ◽  
Catalytic Hydrogenation ◽  
Chemical Reduction ◽  
Pd Nanoparticles ◽  
Catalytic Performance ◽  
Hydrogenation Reaction ◽  
Recyclable Catalyst ◽  
Graphene Aerogels ◽  
Excellent Catalytic Performance

Highly compressible graphene aerogels were made by chemical reduction of graphene oxide with HI, which act as recyclable catalyst to exhibit excellent catalytic performance towards selective semi-hydrogenation reaction after loading Pd nanoparticles.

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.

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