scholarly journals Graphene Oxide Layer-by-Layer Films for Sensors and Devices

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1556
Author(s):  
Ivan C. C. Assunção ◽  
Susana Sério ◽  
Quirina Ferreira ◽  
Nykola C. Jones ◽  
Søren V. Hoffmann ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Electrical Properties ◽  
Vacuum Ultraviolet ◽  
Morphological Characterization ◽  
Linear Increase ◽  
Layer By Layer ◽  
Absorption Bands ◽  
Semiconductor Behavior ◽  
Vacuum Ultraviolet Spectroscopy

Layer-by-layer films of poly (allylamine hydrochloride) (PAH) and graphene oxide (GO) were characterized, looking at growth with the number of bilayers, morphology, and electrical properties. The PAH/GO films revealed a linear increase in absorbance with the increase in the number of deposited bilayers, allowing the determination that 10.7 ± 0.1 mg m−2 of GO is adsorbed per unit of area of each bilayer. GO absorption bands at 146, 210, 247 and 299 nm, assigned to π-π* and n-π* transitions in the aromatic ring (phenol) and of the carboxylic group, respectively, were characterized by vacuum ultraviolet spectroscopy. The morphological characterization of these films demonstrated that they are not completely uniform, with a bilayer thickness of 10.5 ± 0.7 nm. This study also revealed that the films are composed of GO and/or PAH/GO fibers and that GO is completely adsorbed on top of PAH. The electrical properties of the films reveal that PAH/GO films present a semiconductor behavior. In addition, a slight decrease in conduction was observed when films were prepared in the presence of visible light, likely due to the presence of oxygen and moisture that contributes to the damage of GO molecules.

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

2014 ◽  
Vol 86 (5) ◽  
pp. 765-774 ◽  
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.

Morphological Characterization of Chitosan in the Hydroxyapatite/Chitosan Nanocomposites

2009 ◽  
Vol 79-82 ◽  
pp. 1675-1678
Author(s):  
Xiao Ying Lu ◽  
Xiu Hong Wang ◽  
Jian Xin Wang ◽  
Shu Xin Qu ◽  
Jie Weng
Keyword(s):  
Ph Value ◽  
Biomedical Application ◽  
Morphological Characterization ◽  
Layer By Layer ◽  
Oriented Growth ◽  
Hydrothermal Temperature ◽  
Morphological Differences ◽  
Hydrothermal Precipitation

The morphological differences of chitosan (CS) in the hydroxyapatite (HA)/CS nanocomposites were investigated in detailed, which were prepared via in situ hydrothermal precipitation. The results show that the obtained nanocomposites have excellent crystallinity and the crystal has excellent ordered structure, which is important to the composites performances in the biomedical application. Moreover, the CS arrangement and crystallinity in the composites greatly depend on the hydrothermal temperature and the pH value of precipitating agent. The temperature ranging from 373 to 413K and pH value of precipitating agent ranging from 12 to 14 were favorable to the crystallization and oriented growth of CS molecules in the composites. The CS crystals with better arrangement are assembled in the order of layer-by-layer in these composites.

A capillary electrophoresis-based immobilized enzyme reactor using graphene oxide as a support via layer by layer electrostatic assembly

The Analyst ◽  
2014 ◽  
Vol 139 (8) ◽  
pp. 1973-1979 ◽  
Author(s):  
Zhengri Yin ◽  
Wenwen Zhao ◽  
Miaomiao Tian ◽  
Qian Zhang ◽  
Liping Guo ◽  
...  
Keyword(s):  
Capillary Electrophoresis ◽  
Graphene Oxide ◽  
Immobilized Enzyme ◽  
Layer By Layer ◽  
Enzyme Reactor ◽  
Immobilized Enzyme Reactor ◽  
Electrostatic Assembly ◽  
On Line ◽  
Line Analysis

Using graphene oxide as an enzyme support, we developed a novel CE-based microreactor via layer-by-layer electrostatic assembly, which can be used for accurate on-line analysis and characterization of peptides and proteins.

Morphological Characterization of Mycobacteriophage R1

1974 ◽  
Vol 32 ◽  
pp. 254-255
Author(s):  
B. L. Soloff ◽  
T. A. Rado
Keyword(s):  
Carbon Source ◽  
Stationary Phase ◽  
Growth Phase ◽  
Minimal Medium ◽  
Morphological Characterization ◽  
Logarithmic Growth Phase ◽  
Complete Lysis ◽  
Lysogenic Culture ◽  
Logarithmic Growth

Mycobacteriophage R1 was originally isolated from a lysogenic culture of M. butyricum. The virus was propagated on a leucine-requiring derivative of M. smegmatis, 607 leu−, isolated by nitrosoguanidine mutagenesis of typestrain ATCC 607. Growth was accomplished in a minimal medium containing glycerol and glucose as carbon source and enriched by the addition of 80 μg/ ml L-leucine. Bacteria in early logarithmic growth phase were infected with virus at a multiplicity of 5, and incubated with aeration for 8 hours. The partially lysed suspension was diluted 1:10 in growth medium and incubated for a further 8 hours. This permitted stationary phase cells to re-enter logarithmic growth and resulted in complete lysis of the culture.

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