scholarly journals LIPSS Structures Induced on Graphene-Polystyrene Composite

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3460 ◽  
Author(s):  
Dominik Fajstavr ◽  
Klára Neznalová ◽  
Václav Švorčík ◽  
Petr Slepička
Keyword(s):  
Chemical Properties ◽  
Laser Pulses ◽  
Periodic Pattern ◽  
Krypton Fluoride ◽  
Periodic Surface ◽  
Laser Modification ◽  
Force Microscopy ◽  
Periodic Surface Structure ◽  
Atomic Force ◽  
Physico Chemical

A laser induced periodic surface structure (LIPSS) on graphene doped polystyrene was prepared by the means of a krypton fluoride (KrF) laser with the wavelength of 248 nm and precisely desired physico-chemical properties were obtained for the structure. Surface morphology after laser modification of polystyrene (PS) doped with graphene nanoplatelets (GNP) was studied. Laser fluence values of modifying laser light varied between 0–40 mJ·cm−2 and were used on polymeric PS substrates doped with 10, 20, 30, and 40 wt. % of GNP. GNP were incorporated into PS substrate with the solvent casting method and further laser modification was achieved with the same amount of laser pulses of 6000. Formed nanostructures with a periodic pattern were examined by atomic force microscopy (AFM). The morphology was also studied with scanning electron microscopy SEM. Laser irradiation resulted in changes of chemical composition on the PS surface, such as growth of oxygen concentration. This was confirmed with energy-dispersive X-ray spectroscopy (EDS).

Preparation of Giant Unilamellar Vesicles and Solid Supported Bilayer from Large Unilamellar Vesicles: Model Biological Membranes

2017 ◽  
Vol 32 (3-4) ◽  
pp. 85 ◽  
Author(s):  
Amrita Basu ◽  
Pabitra Maity ◽  
Prasanta Karmakar ◽  
Sanat Karmakar
Keyword(s):  
Chemical Properties ◽  
Giant Unilamellar Vesicles ◽  
Unilamellar Vesicles ◽  
Force Microscopy ◽  
Atomic Force ◽  
Large Unilamellar Vesicles ◽  
Physico Chemical ◽  
Micron Size ◽  
Planar Membranes ◽  
Extrusion Method

Giant Unilamellar Vesicles (GUV) and supported planar membranes are excellent model biological systems for studying the structure and functions of membranes. We have prepared GUV from Large Unilamellar Vesicles (LUV) using electroformation and Supported planar Lipid Bilayer (SLB) by vesicle fusion method. LUV was prepared using an extrusion method and was characterized using Dynamic Light Scattering (DLS) and zeta potential measurements. The techniques for obtaining GUV as well as SLB from LUV have been demonstrated. We have directly observed the formation of GUV under phase contrast microscopy. This study will provide some insights into the physico-chemical properties of both nano and micron size vesicles. We believe that this method could be extremely useful for reconstituting various bio-molecules in GUV. We have presented one example where an antimicrobial peptide NK-2 was reconstituted in GUV prepared from LUV. SLB formation was monitored and characterized using Atomic Force Microscopy (AFM).

scholarly journals Electrospun Combination of Peppermint Oil and Copper Sulphate with Conducive Physico-Chemical properties for Wound Dressing Applications

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 586 ◽  
Author(s):  
Saravana Jaganathan ◽  
Mohan Mani ◽  
Ahmad Khudzari
Keyword(s):  
Surface Roughness ◽  
Copper Sulphate ◽  
Wound Dressing ◽  
Fiber Diameter ◽  
Blood Compatibility ◽  
Chemical Properties ◽  
Force Microscopy ◽  
Atomic Force ◽  
Physico Chemical ◽  
Afm Analysis

The ultimate goal in tissue engineering is to fabricate a scaffold which could mimic the native tissue structure. In this work, the physicochemical and biocompatibility properties of electrospun composites based on polyurethane (PU) with added pepper mint (PM) oil and copper sulphate (CuSO4) were investigated. Field Emission Electron microscope (FESEM) study depicted the increase in mean fiber diameter for PU/PM and decrease in fiber diameter for PU/PM/CuSO4 compared to the pristine PU. Fourier transform infrared spectroscopy (FTIR) analysis revealed the formation of a hydrogen bond for the fabricated composites as identified by an alteration in PU peak intensity. Contact angle analysis presented the hydrophobic nature of pristine PU and PU/PM while the PU/PM/CuSO4 showed hydrophilic behavior. Atomic force microscopy (AFM) analysis revealed the increase in the surface roughness for the PU/PM while PU/PM/CuSO4 showed a decrease in surface roughness compared to the pristine PU. Blood compatibility studies showed improved blood clotting time and less toxic behavior for the developed composites than the pristine PU. Finally, the cell viability of the fabricated composite was higher than the pristine PU as indicated in the MTS assay. Hence, the fabricated wound dressing composite based on PU with added PM and CuSO4 rendered a better physicochemical and biocompatible nature, making it suitable for wound healing applications.

Anodized Aluminum Oxide Films as Nanostructured Template for the Grow of Carbon Nanotubes

2000 ◽  
Vol 633 ◽  
Author(s):  
Y.C. Sui ◽  
J.A. González-León ◽  
A. Bermùdez ◽  
D.R. Acosta ◽  
J. Feuchtwanger ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Chemical Properties ◽  
Wall Structure ◽  
Anodized Aluminum ◽  
Anodized Aluminum Oxide ◽  
Force Microscopy ◽  
Work Related ◽  
Atomic Force ◽  
Physico Chemical ◽  
Alumina Oxide

AbstractA summary of our recent work related to the growth of carbon nanotubes (CNTs) inside the pores of anodized alumina oxide (AAO) films is presented. The surface topography of the AAO film was studied by atomic force microscopy, while the internal pore structure of the AOO templates was concluded from the shape of the CNTs obtained. The effect of the different experimental approaches and of the anodization voltage value on the features of the pores and CNTs is also discussed, as well as the catalytic effect in the acetylene pyrolysis of the Co particles and internal alumina walls. The CNTs wall structure observed by HRTEM and its implication on some physico-chemical properties of the CNTs are also presented.

Infrared Characterization of PMMA-SiO2 Hybrid Glasses Obtained by Sol-Gel Process

2010 ◽  
Vol 1278 ◽  
Author(s):  
L.L. Díaz-Flores ◽  
A. S. López Rodríguez ◽  
P. SifuentesGallardo ◽  
M.A. Hernàndez Rivera ◽  
M.a Garnica Romo ◽  
...  
Keyword(s):  
Sol Gel ◽  
Chemical Properties ◽  
Hybrid Coatings ◽  
Force Microscopy ◽  
Air Atmosphere ◽  
Atomic Force ◽  
Sol Gel Process ◽  
Traditional Process ◽  
And Chemical Properties

AbstractThis work is about the production of hybrid coatings of the system SiO2-PMMA (PMMA, polymethylmethacrylate). These materials have interesting mechanical and chemical properties useful for anticorrosive and wear resistance applications. SiO2-PMMA hybrids were obtained by the sol-gel traditional process, using tetraethylorthosilicate (TEOS) and methylmethacrylate (MMA) by Aldrich Co, as starting reagents. The SiO2:PMMA ratio was varied from 0:1 to about 1:1 at air atmosphere deposition. The coatings were obtained on acrylic sheets and silicon wafers. A diversity of coatings with chemical composition ranging from SiO2 and PMMA to obtain the SiO2-PMMA hybrids were obtained. Infrared (IR) and atomic force microscopy (AFM), were performed to determinate structural and morphological behavior.

Stereocomplex electrospun fibers from high molecular weight of poly(L-lactic acid) and poly(D-lactic acid)

2020 ◽  
Vol 40 (2) ◽  
pp. 136-142 ◽  
Author(s):  
Homa Maleki ◽  
Hossein Barani
Keyword(s):  
Molecular Weight ◽  
Lactic Acid ◽  
Thermal Properties ◽  
High Molecular Weight ◽  
Chemical Properties ◽  
Electrospun Fibers ◽  
Scanning Calorimetry ◽  
Force Microscopy ◽  
Atomic Force ◽  
Electrospinning Method

AbstractThe stereocomplex formation is a promising method to improve the properties of poly(lactide) (PLA)-based products due to the strong interaction of the side-by-side arrangement of the molecular chains. Recently, electrospinning method has been applied to prepare PLA stereocomplex, which is more convenient. The objective of the current study is to make stereocomplexed PLA nanofibers using electrospinning method and compare their properties and structures with pure poly(l-lactide) (PLLA) fibers. The stereocomplexed fibers were electrospun from a blend solution of high molecular weight PLLA and poly(d-lactide) (1:1 ratio). The morphology of the obtained electrospun fibers was examined by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Differential scanning calorimetry was applied to study their thermal properties and crystallinity. Fourier transform infrared spectroscopy (FTIR) test was conducted on the samples to characterize their chemical properties. The SEM and AFM images indicated that smooth uniform fibers with a cylindrical structure were produced. Besides, the FTIR results and thermal properties confirmed that only stereocomplex crystallites formed in the resulting fibers via the electrospinning method.

Carbon Fiber Surface Modification by Plasma Treatment for Interface Adhesion Improvements of Aerospace Composites

2016 ◽  
Vol 1135 ◽  
pp. 75-87 ◽  
Author(s):  
Alberto Lima Santos ◽  
Edson Cocchieri Botelho ◽  
Konstantin Georgiev Kostov ◽  
Mario Ueda ◽  
Leide Lili G. da Silva
Keyword(s):  
Carbon Fibers ◽  
Photoelectron Spectroscopy ◽  
Fiber Surface ◽  
Polyphenylene Sulfide ◽  
Thermoplastic Composite ◽  
Force Microscopy ◽  
Atomic Force ◽  
Physico Chemical ◽  
Plasma Immersion Ion Implantation ◽  
Interlaminar Shear

This paper is focused on the processing of thermoplastic composite materials obtained from carbon fibers (CFs) treated by plasma assisted techniques. The treatments employed in this work were the Dielectric Barrier Discharge (DBD), which is done at atmospheric pressure, involving lower energies and the Plasma Immersion Ion Implantation (PIII), which is performed at low pressure, involving higher energies. After the treatments, samples characterizations were performed to determine which treatment is most effective to get better physico-chemical CF surface properties. The techniques employed in this work in order to evaluate the surface treatment were: scanning electron microscopy (SEM); atomic force microscopy (AFM) Raman spectroscopy and x-ray photoelectron spectroscopy (XPS). Treated and untreated CFs/Polyphenylene sulfide (PPS) composites were processed by hot-compression molding technique. These composites were evaluated by interlaminar shear tests (ILSS). After analyzing the results, it was found that the treatments increased the CF roughness and caused slight changes in the CF structure. In addition, there was an increase in the shear strength of the composites obtained from treated fibers by both plasma processes. In conclusion, DBD and PIII treatments are effective tools for improving adhesion between CF and the polymeric matrix.

Femtosecond Laser Micromachining of Periodical Structures in Si

2004 ◽  
Vol 850 ◽  
Author(s):  
Mohamed El-Bandrawy ◽  
Mool C. Gupta
Keyword(s):  
Laser Pulses ◽  
Light Polarization ◽  
Objective Lens ◽  
Force Microscopy ◽  
Laser Parameters ◽  
Femtosecond Laser Micromachining ◽  
Atomic Force ◽  
Fs Laser ◽  
Polarization Orientation

ABSTRACTA frequency doubled femtosecond Ti: sapphire laser at a wavelength of 400 nm, a pulse width of 160 fs, and a repetition rate of 1 kHz was used with a computer controlled galvo head to write periodical structures in Si <100>. Laser pulses of ∼130 nJ were focused using an objective lens of 0.65 NA. Laser parameters were optimized for efficient submicron ablation, yielding 700 nm wide by 600 nm deep lines. 1-D and 2-D periodical structures of 5 and 5x5 micron periods, respectively, were fabricated and examined using optical and atomic force microscopy. The quality of the 1-D and 2-D structures was highly depended on the light polarization orientation with respect to micromachining direction. With optimized fs laser parameters, high quality 1-D and 2-D periodical structures were obtained, which would have applications in optical devices.

Atomic Force Microscopy Of Micron Size Silicalite Crystals

1991 ◽  
Vol 233 ◽  
Author(s):  
P. Rasch ◽  
W. M. Heckl ◽  
H. W. Deckman ◽  
W. Häberle
Keyword(s):  
Perfect Crystal ◽  
Periodic Pattern ◽  
Crystal Surfaces ◽  
Force Microscopy ◽  
Atomic Force ◽  
Micron Size ◽  
Unit Cells ◽  
High Resolution Images ◽  
Long Range Ordering ◽  
Surface Crystallography

ABSTRACTWe have imaged micron sized silicalite crystals with an atomic force microscope (AFM). High resolution images taken in the repulsive mode show a periodic pattern that locally has a symmetry and periodicity which can be mapped onto the expected image looking along the [010] direction. Extra spots, however, appear in the image in regions which should correspond to channels exposed at the surface. These extra spots are attributed to multiple tip effects which should not affect the ability to detect long range ordering. On a scale length of ˜ 3 – 5 unit cells, the ordering in images deviates from that expected for a perfect crystal. This may be due to imperfections in the ordering at crystal surfaces. One other important aspect of the surface crystallography is revealed in low resolution scans where definite steps / grooves in the exposed surface are seen. The results are discussed in terms of the potential of AFM as a probe of surface crystallography.

Direct laser patterning of GaAs(001) surfaces

2014 ◽  
Vol 1628 ◽  
Author(s):  
Haeyeon Yang
Keyword(s):  
Laser Intensity ◽  
Laser Pulses ◽  
Patterned Surfaces ◽  
Power Laser ◽  
Force Microscopy ◽  
Patterned Surface ◽  
Laser Patterning ◽  
Atomic Force ◽  
Plateau Area ◽  
Direct Laser

ABSTRACTAnalysis of surface images indicates that GaAs(001) surfaces can be patterned directly by applying interferential irradiation of high power laser pulses on the surface. Atomic force microscopy (AFM) was used to image the patterned surfaces. The patterned surface shows strips that have the same separation as the interference period used. The direct laser patterning leaves the surface with trenches. The depth of trenches increases with the laser intensity and can be varied from few nanometers to a few hundred nanometers. At low laser intensity, strip shaped mound appears at the both edges of a trench, leaving a plateau area between them. The width of mound increases with the laser intensity, making the plateau area smaller. With a higher laser intensity, the plateau area disappear as the mounds merge together, forming a single strip between the adjacent trenches. AFM images from the patterned surface indicate that direct laser patterning can be used to fabricate nanostructures with a period smaller than that of the interference period as well as the wavelength of the laser used.

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