scholarly journals Fabrication of hybrid graphene oxide/polyelectrolyte capsules by means of layer-by-layer assembly on erythrocyte cell templates

2015 ◽  
Vol 6 ◽  
pp. 2310-2318 ◽  
Author(s):  
Joseba Irigoyen ◽  
Nikolaos Politakos ◽  
Eleftheria Diamanti ◽  
Elena Rojas ◽  
Marco Marradi ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Layer By Layer ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Layer Technique ◽  
Polyallylamine Hydrochloride ◽  
Layer By Layer Technique ◽  
Layer Assembly ◽  
Shape And Size

A novel and facile method was developed to produce hybrid graphene oxide (GO)–polyelectrolyte (PE) capsules using erythrocyte cells as templates. The capsules are easily produced through the layer-by-layer technique using alternating polyelectrolyte layers and GO sheets. The amount of GO and therefore its coverage in the resulting capsules can be tuned by adjusting the concentration of the GO dispersion during the assembly. The capsules retain the approximate shape and size of the erythrocyte template after the latter is totally removed by oxidation with NaOCl in water. The PE/GO capsules maintain their integrity and can be placed or located on other surfaces such as in a device. When the capsules are dried in air, they collapse to form a film that is approximately twice the thickness of the capsule membrane. AFM images in the present study suggest a film thickness of approx. 30 nm for the capsules in the collapsed state implying a thickness of approx. 15 nm for the layers in the collapsed capsule membrane. The polyelectrolytes used in the present study were polyallylamine hydrochloride (PAH) and polystyrenesulfonate sodium salt (PSS). Capsules where characterized by transmission electron microscopy (TEM), atomic force microscopy (AFM), dynamic light scattering (DLS) and Raman microscopy, the constituent layers by zeta potential and GO by TEM, XRD, and Raman and FTIR spectroscopies.

Study of Layer-by-Layer Assembly of a Xanthane Dye by Spectroscopy and Atomic Force Microscopy

2017 ◽  
Vol 12 (1) ◽  
pp. 22-28
Author(s):  
Bandana Das ◽  
Banti Ganguly ◽  
Indra Ghosh ◽  
Ranendu Kumar Nath ◽  
Bijay Kumar Mishra ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Layer By Layer ◽  
Force Microscopy ◽  
Atomic Force ◽  
Layer By Layer Assembly ◽  
Layer Assembly

scholarly journals Hybrid poly(allylamine hydrochloride)–graphene oxide microcapsules: preparation, characterization and application in textiles with controlled release behavior

2020 ◽  
Vol 1 (4) ◽  
pp. 804-813
Author(s):  
Zhiqi Zhao ◽  
Qiujin Li ◽  
Jixian Gong ◽  
Zheng Li ◽  
Jianfei Zhang
Keyword(s):  
Graphene Oxide ◽  
Controlled Release ◽  
Cotton Fabric ◽  
Near Infrared ◽  
Layer By Layer ◽  
Release Behavior ◽  
Layer Technique ◽  
Allylamine Hydrochloride ◽  
Behavior Based ◽  
Layer By Layer Technique

This work represents hybrid poly(allylamine hydrochloride)-graphene oxide microcapsules formed via layer-by-layer technique, which can be coated on cotton fabric for textiles with controlled release behavior, based on pH and near-infrared responsiveness.

Characterization of nano-structured poly(ε-caprolactone) membranes with DNA-doped polypyrrole via sonication-induced layer-by-layer assembly

2018 ◽  
Vol 89 (7) ◽  
pp. 1267-1275
Author(s):  
Geon Jin Kim ◽  
Kee Jong Yoon ◽  
Ick Soo Kim ◽  
Kyu Oh Kim
Keyword(s):  
Contact Angle ◽  
Fiber Diameter ◽  
Good Survival ◽  
Cytotoxicity Test ◽  
Layer By Layer ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Layer By Layer Assembly ◽  
Layer Assembly

In this study, the formation of conductive nano-structured polypyrrole (PPy) on electrospun poly(ɛ-caprolactone) (PCL) nanofibers was successfully achieved using a DNA dopant (PCL/DNA-PPy) via sonication-induced layer-by-layer assembly. After PPy containing positive charges was accumulated on PCL, DNAs with negative charges deposited such that they were evenly distributed. The resulting PCL/DNA-PPy nanomembrane exhibited increased fiber diameter (PCL/DNA-PPy 5LBL: 328.11 ± 48 nm) and deformation morphology compared to pure PCL (average fiber diameter of 247.25 ± 32 nm, fibrous uniform morphology), as observed using scanning electron microscopy and atomic force microscopy. As the number of layers increased, the crystallinity of PCL/DNA–PPy nanomembranes decreased, as observed using X-ray diffraction. It was observed that the PPy-DNA deposited on the surface of PCL connected to form a nano-sheath and significantly increased the thermal stability of PCL. Moreover, the contact angle of the PCL/DNA-PPy nanomembrane (contact angle of pure PCL: 79.3 ± 1.2°) demonstrated its high hydrophilicity. The results indicate that the composites showed very good survival in a cytotoxicity test on U-118 glioma cells and excellent electrical conductivity (the highest value was 1.1 × 10−3 S/m). The manufactured PCL/DNA–PPy nanomembranes are considered to be promising materials for applications in the scaffold, sensor, and electronic fields.

Layer-by-layer assembly of exfoliated layered double hydroxide nanosheets for enhanced electrochemical oxidation of water

2016 ◽  
Vol 4 (29) ◽  
pp. 11516-11523 ◽  
Author(s):  
Cong Zhang ◽  
Jingwen Zhao ◽  
Lei Zhou ◽  
Zhenhua Li ◽  
Mingfei Shao ◽  
...  
Keyword(s):  
Electrochemical Oxidation ◽  
Layered Double Hydroxide ◽  
Ultrathin Films ◽  
Layer By Layer ◽  
Layer By Layer Assembly ◽  
Layer Technique ◽  
Double Hydroxide ◽  
Layer By Layer Technique ◽  
Layer Assembly

Well-ordered (CoNi-LDH/Fe-PP)nultrathin films were obtained through a layer-by-layer technique, which exhibit largely enhanced OER performance.

Dynamic Self-Assembly Process of a Designed Peptide

2013 ◽  
Vol 750-752 ◽  
pp. 1630-1634
Author(s):  
Li Ping Ruan ◽  
Zhi Hua Xing
Keyword(s):  
Atomic Force Microscopy ◽  
Self Assembly ◽  
The Self ◽  
Layer By Layer ◽  
Assembly Process ◽  
Force Microscopy ◽  
Atomic Force ◽  
Sheet Structure ◽  
Β Sheet ◽  
Layer Assembly

In this paper, we reported the dynamic self-assembly process of an half-sequence ionic self-complementarity peptide CH3CO-Pro-Ser-Phe-Cys-Phe-Lys-Phe-Glu-Pro-NH2, which could self-assemble into stable nanofibers and formed hydrogel consisting of >99% water. The dynamic self-assembly process was detected by circular dichroism (CD) and atomic force microscopy (AFM). CD spectrum revealed that the mainly contents of the peptide were regular β-sheet structure. The data indicated that though the secondary structure of the peptide formed immediately, the microstructure of the self-assembly process of the designed peptide formed slowly. AFM image illustrated that the self-assembly process was layer-by-layer assembly.

scholarly journals Enhancement of barrier and anti-corrosive performance of zinc-rich epoxy coatings using nano-silica/graphene oxide hybrid

2020 ◽  
Vol 38 (6) ◽  
pp. 497-513
Author(s):  
Meiling Zhang ◽  
Hui Wang ◽  
Ting Nie ◽  
Jintao Bai ◽  
Fei Zhao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Corrosion Protection ◽  
Electrochemical Impedance ◽  
Epoxy Coating ◽  
X Ray Diffraction ◽  
Protection Efficiency ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron

AbstractThis study reports a facile method to prepare silica-coated graphene oxide nanoflakes (SiO2–GO). Results of X-ray diffraction analysis, Raman spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy and atomic force microscopy reveal that silica was successfully coated on the GO flakes. The effect of SiO2–GO nanosheets on the corrosion protection and barrier performance of the epoxy coating was investigated in this work. Results indicate that the mechanical properties of all coatings added with GO and SiO2–GO were significantly improved. Furthermore, electrochemical impedance and Tafer polarisation curves showed that added 0.5 wt% SiO2–GO nanoflakes into zinc-rich epoxy coating could greatly improve the anti-corrosion performance of the sample, and the corrosion protection efficiency increased from 67.01 to 99.58%.

scholarly journals Flexible Transparent Electrode Characteristics of Graphene Oxide/Cysteamine/AgNP/AgNW Structure

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2352
Author(s):  
Junhwan Jang ◽  
Ju-Young Choi ◽  
Jihyun Jeon ◽  
Jeongjun Lee ◽  
Jaehyuk Im ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Optical Transmittance ◽  
Transparent Electrode ◽  
Silver Nanowire ◽  
Bending Test ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Current Voltage

Graphene oxide (GO)–cysteamine–Ag nanoparticles (GCA)–silver nanowire (AgNW) fabricated by depositing GCA over sprayed AgNWs on PET films were proposed for transparent and flexible electrodes, and their optical, electrical, and mechanical properties were analyzed by energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, Raman spectroscopy, atomic force microscopy, scanning electron microscopy, transmission electron microscopy, current-voltage measurements, and bending test. GCA–AgNW electrodes show optical transmittance of >80% at 550 nm and exhibit a high figure-of-merit value of up to 116.13 in the samples with sheet resistances of 20–40 Ω/◻. It was observed that the detrimental oxidation of bare AgNWs over time was considerably decreased, and the mechanical robustness was improved. To apply the layer as an actual electrode in working devices, a Pt/GO/poly(3,4-ethylenedioxythiophene) polystyrene sulfonate/GCA–AgNW/polyethylene terephthalate structure was fabricated, and resistive switching memory was demonstrated. On the basis of these results, we confirm that the proposed GCA–AgNW layer can be used as transparent and flexible electrode.

Preparation and properties of chemically reduced graphene oxide/copolymer-polyamide nanocomposites

e-Polymers ◽  
2017 ◽  
Vol 17 (1) ◽  
pp. 3-14 ◽  
Author(s):  
Xin Liu ◽  
Xiao Yu Shao ◽  
Guan Biao Fang ◽  
Hai Feng He ◽  
Zhen Gao Wan
Keyword(s):  
Electrical Conductivity ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Xrd Analysis ◽  
Sem Analysis ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Reduced Graphene ◽  
Chemically Reduced Graphene Oxide

AbstractTo enhance the physical properties of copolymer-polyamide (CO-PA), a sequence of nanocomposites based upon CO-PA and chemically reduced graphene oxide (CRGO) nanoplatelets were prepared by in-situ reduction using hydrazine hydrate. Graphene oxide (GO), prepared by the improved Hummers method, was used to fabricate CRGO nanaoplatelets. Atomic-force microscopy (AFM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) analysis showed that the thickness and the width of GO was about 0.9 nm and 1 μm, respectively. An abundance of oxygen-containing functional groups were introduced onto the GO sheets. XRD and SEM analysis showed that CRGO nanoplatelets were well dispersed in the CO-PA matrix with the appropriate CRGO content. TGA and DSC analysis demonstrated that CRGO nanoplatelets can significantly improve the thermal stability, glass-transition temperature, crystallization temperature of the composites. The mechanical properties of the nanocomposites were improved significantly with the appropriate increment of CRGO nanoplatelets content, though the elongation at break of the composites decreased with the increase of CRGO nanoplatelets content. The electrical conductivity test showed a significant increase in electrical conductivity from an insulator to almost a semiconductor with increasing CRGO nanoplatelets content. And at 1.0 wt% CRGO content, the electrical percolation threshold of the nanocomposites was found.

scholarly journals Determination of Particle Shape and Size Distribution of Model Types of Nanomaterials

2010 ◽  
Vol 61 (5) ◽  
pp. 302-304 ◽  
Author(s):  
Edita Bretšnajdrová ◽  
Ladislav Svoboda ◽  
Jiří Zelenka
Keyword(s):  
Size Distribution ◽  
Particle Shape ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Paint Industry ◽  
The Given ◽  
Detailed Chemical ◽  
Shape And Size

Determination of Particle Shape and Size Distribution of Model Types of Nanomaterials At present, great attention is given to study of preparation and properties of various nanomaterials usable in many applications. They are utilized in varied fields of human activity - eg in electronics, medicine, paint industry etc. Besides the detailed chemical structure, such nanoparticle properties as the shape and size distribution are fundamental to the given application. To measure these parameters various methods are used, e.g. transmission electron microscopy (TEM), atomic force microscopy (AFM), acoustic spectrometry, methods based on the light scattering and X-ray disc centrifuge system.

Investigation of Growth Evolution in c-Axis SrBi2Nb2O9 Epitaxial Thin Films

1999 ◽  
Vol 574 ◽  
Author(s):  
J. Lettieri ◽  
M. A. Zurbuchen ◽  
G. W. Brown ◽  
Y. Jia ◽  
W. Tian ◽  
...  
Keyword(s):  
Thin Films ◽  
Rutherford Backscattering Spectrometry ◽  
Growth Conditions ◽  
Layer Growth ◽  
Spiral Growth ◽  
Layer By Layer ◽  
Epitaxial Thin Films ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron

Abstract(001)-oriented epitaxial SrBi2Nb2O9 thin films have been grown by pulsed laser deposition on (001) SrTiO3 and (001) LaAlO3—Sr2AlTaO6 substrates at optimized growth conditions. 4-circle x-ray diffraction, Rutherford backscattering spectrometry, and transmission electron microscopy reveal highly oriented epitaxial films. Atomic force microscopy indicates spiral growth for films grown on SrTiO3 and layer-by-layer growth for films grown on LaAlO3—Sr2AlTaO6.

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