scholarly journals Characterisation of PMMA/ATH Layers Realised by Means of Atmospheric Pressure Plasma Powder Deposition

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Lena M. Wallenhorst ◽  
Sebastian Dahle ◽  
Matej Vovk ◽  
Lisa Wurlitzer ◽  
Leander Loewenthal ◽  
...  

We report on the characteristics of aluminium trihydrate filled poly(methyl methacrylate) composite (PMMA/ATH) coatings realised by plasma deposition at atmospheric pressure. For this purpose, PMMA/ATH powder was fed to a plasma jet where the process and carrier gas was compressed air. The deposited coatings were investigated by X-ray photoelectron spectroscopy and water contact angle measurements. Further, the raw material was characterised before deposition. It was found that, with respect to the raw material, aluminium was uncovered in the course of the plasma deposition process which can be explained by plasma-induced etching of the PMMA matrix. As a result, the wettability of plasma-deposited PMMA/ATH was significantly increased. Even though a uniform coating film could not be realised as ascertained by confocal laser scanning microscopy, the deposited coatings feature notably enhanced characteristics which could be advantageous for further processing.

2020 ◽  
Vol 11 (1) ◽  
pp. 44
Author(s):  
Sergej Medved ◽  
Daša Krapež Tomec ◽  
Angela Balzano ◽  
Maks Merela

Since invasive alien species are one of the main causes of biodiversity loss in the region and thus of changes in ecosystem services, it is important to find the best possible solution for their removal from nature and the best practice for their usability. The aim of the study was to investigate their properties as components of wood-plastic composites and to investigate the properties of the wood-plastic composites produced. The overall objective was to test the potential of available alien plant species as raw material for the manufacture of products. This would contribute to sustainability and give them a better chance of ending their life cycle. One of the possible solutions on a large scale is to use alien wood species for the production of wood plastic composites (WPC). Five invasive alien hardwood species have been used in combination with polyethylene powder (PE) and maleic anhydride grafted polyethylene (MAPE) to produce various flat pressed WPC boards. Microstructural analyses (confocal laser scanning microscopy and scanning electron microscopy) and mechanical tests (flexural strength, tensile strength) were performed. Furthermore, measurements of density, thickness swelling, water absorption and dimensional stability during heating and cooling were carried out. Comparisons were made between the properties of six WPC boards (five alien wood species and mixed boards). The results showed that the differences between different invasive alien wood species were less obvious in mechanical properties, while the differences in sorption properties and dimensional stability were more significant. The analyses of the WPC structure showed a good penetration of the polymer into the lumens of the wood cells and a fine internal structure without voids. These are crucial conditions to obtain a good, mechanically strong and water-resistant material.


Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 464
Author(s):  
Simona Liliana Iconaru ◽  
Mihai Valentin Predoi ◽  
Patrick Chapon ◽  
Sofia Gaiaschi ◽  
Krzysztof Rokosz ◽  
...  

In this study, the cerium-doped hydroxyapatite (Ca10−xCex(PO4)6(OH)2 with xCe = 0.1, 10Ce-HAp) coatings obtained by the spin coating method were presented for the first time. The stability of the 10Ce-HAp suspension particles used in the preparation of coatings was evaluated by ultrasonic studies, transmission electron microscopy (TEM), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The surface morphology of the 10Ce-HAp coating was studied by SEM and atomic force microscopy (AFM) techniques. The obtained 10Ce-HAp coatings were uniform and without cracks or unevenness. Glow discharge optical emission spectroscopy (GDOES) and X-ray photoelectron spectroscopy (XPS) were used for the investigation of fine chemical depth profiling. The antifungal properties of the HAp and 10Ce-HAp suspensions and coatings were assessed using Candida albicans ATCC 10231 (C. albicans) fungal strain. The quantitative antifungal assays demonstrated that both 10Ce-HAp suspensions and coatings exhibited strong antifungal properties and that they successfully inhibited the development and adherence of C. albicans fungal cells for all the tested time intervals. The scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) visualization of the C. albicans fungal cells adherence to the 10Ce-HAp surface also demonstrated their strong inhibitory effects. In addition, the qualitative assays also suggested that the 10Ce-HAp coatings successfully stopped the biofilm formation.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ata Aditya Wardana ◽  
Arisa Koga ◽  
Fumina Tanaka ◽  
Fumihiko Tanaka

AbstractA novel composite edible coating film was developed from 0.8% chitosan (CS) and 0.5% sandalwood oil (SEO). Cellulose nanofibers (CNFs) were used as a stabilizer agent of oil-in-water Pickering emulsion. We found four typical groups of CNF level-dependent emulsion stabilization, including (1) unstable emulsion in the absence of CNFs; (2) unstable emulsion (0.006–0.21% CNFs); (3) stable emulsion (0.24–0.31% CNFs); and (4) regular emulsion with the addition of surfactant. Confocal laser scanning microscopy was performed to reveal the characteristics of droplet diameter and morphology. Antifungal tests against Botrytis cinerea and Penicillium digitatum, between emulsion coating stabilized with CNFs (CS-SEOpick) and CS or CS-SEO was tested. The effective concentration of CNFs (0.24%) may improve the performance of CS coating and maintain CS-SEO antifungal activity synergistically confirmed with a series of assays (in vitro, in vivo, and membrane integrity changes). The incorporation of CNFs contributed to improve the functional properties of CS and SEO-loaded CS including light transmission at UV and visible light wavelengths and tensile strength. Atomic force microscopy and scanning electron microscopy were employed to characterize the biocompatibility of each coating film formulation. Emulsion-CNF stabilized coating may have potential applications for active coating for fresh fruit commodities.


Molecules ◽  
2020 ◽  
Vol 25 (24) ◽  
pp. 6024
Author(s):  
Sandra Gaiser ◽  
Urs Schütz ◽  
Patrick Rupper ◽  
Dirk Hegemann

The concept of depositing solid films on low-vapor pressure liquids is introduced and developed into a top-down approach to functionalize surfaces by attaching liquid polyethylene glycol (PEG). Solid-liquid gradients were formed by low-pressure plasma treatment yielding cross-linking and/or deposition of a plasma polymer film subsequently bound to a flexible polydimethylsiloxane (PDMS) backing. The analysis via optical transmission spectroscopy (OTS), optical, confocal laser scanning (CLSM) and scanning electron microscopy (SEM), Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) as well as by water contact angle (WCA) measurements revealed correlations between optical appearance, chemical composition and surface properties of the resulting water absorbing, covalently bound PEG-functionalized surfaces. Requirements for plasma polymer film deposition on low-vapor pressure liquids and effective surface functionalization are defined. Namely, the thickness of the liquid PEG substrate was a crucial parameter for successful film growth and covalent attachment of PEG. The presented method is a practicable approach for the production of functional surfaces featuring long-lasting strong hydrophilic properties, making them predestined for non-fouling or low-friction applications.


2012 ◽  
Vol 487 ◽  
pp. 730-734 ◽  
Author(s):  
Chang Jiang Pan ◽  
Yu Dong Nie ◽  
Yun Xiao Dong

In this paper, two kinds of stamps (squares (a×a)) separated by spacing b, the values of a and b were varied from 2.5 µm to 50 µm), i.e. positive and negative stamps, were prepared. The stamps inked with the rhodamine-labeled bovine serum albumin (BSA) were then microcontacted with the aldehyde-functionalized titanium surfaces. Water contact angle and X-ray photoelectron spectrum (XPS) indicated that BSA can be covalently immobilized on aldehyde modified titanium surface by microcontact printing. The experimental results of CLSM showed that the patterns with resolution from 2.5 µm to 50 µm were obtained successfully. Both positive stamp and negative stamp were deformed when the value of a was less than or equal to 5 µm, which resulted in replication errors. Furthermore, the larger spacing (50 µm) resulted in stamp collapse when the value a of the positive stamp was less than or equal to 10 µm, leading to whole fluorescence on substrates.


2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
C. S. Ciobanu ◽  
A. Groza ◽  
S. L. Iconaru ◽  
C. L. Popa ◽  
P. Chapon ◽  
...  

The goal of this study was the preparation, physicochemical characterization, and microbiological evaluation of novel hydroxyapatite doped with silver/polydimethylsiloxane (Ag:HAp-PDMS) composite layers. In the first stage, the deposition of polydimethylsiloxane (PDMS) polymer layer on commercially pure Si disks has been produced in atmospheric pressure corona discharges. Finally, the new silver doped hydroxyapatite/polydimethylsiloxane composite layer has been obtained by the thermal evaporation technique. The Ag:HAp-PDMS composite layers were characterized by various techniques, such as Scanning Electron Microscopy (SEM), Glow Discharge Optical Emission Spectroscopy (GDOES), and X-ray photoelectron spectroscopy (XPS). The antimicrobial activity of the Ag:HAp-PDMS composite layer was assessed againstCandida albicansATCC 10231 (ATCC—American Type Culture Collection) by culture based and confirmed by SEM and Confocal Laser Scanning Microscopy (CLSM) methods. This is the first study reporting the antimicrobial effect of the Ag:HAp-PDMS composite layer, which proved to be active againstCandida albicansbiofilm embedded cells.


2013 ◽  
Vol 67 (1) ◽  
Author(s):  
Martin Danko ◽  
Matej Mičušík ◽  
Mária Omastová ◽  
Juraj Bujdák ◽  
Dušan Chorvát

AbstractNew fluorescence dyes with an alkoxysilane moiety were synthesised by the condensation of 3-(triethoxysilyl)-1-propanamine (3-aminopropyltriethoxysilane) with 4,10-benzothioxanthene-3,1′-dicarboxylic acid anhydride (BTXA) and N,N-dimethylaminonaphthalene-1,8-dicarboxylic acid anhydride (DMANA), which was accompanied by the formation of an imidic bridge. The compounds N-(3-(triethoxysilyl)propyl)-thioxantheno[2,1,9-dej]isoquinoline-1,3-dione (BTX-S) and 4-(N′, N′-dimethyl)-N-(triethoxysilyl)propyl-1,8-naphthalene dicarboxylic acid imide (DMAN-S) were characterised by steady-state and time-resolved fluorescence spectroscopy in chloroform and ethanol. Both conjugates (BTX-S and DMAN-S) exhibited absorption and emission bands in the same region as the un-substituted BTXA and DMANA. An important Stokes shift was observed for DMAN-S in ethanol. A high fluorescence quantum yield was observed for BTX-S in both solvents and for DMAN-S in chloroform. In addition, the newly developed fluorescent silane dyes were covalently attached to the microscopic particles of layered silicates and on the surface of SiO2 wafers as a proof of concept for fluorescence particle (surface) visualisation. The surface wafer modification was precisely characterised by X-ray photoelectron spectroscopy (XPS). Successful covalent linkage onto the particles of layered silicates was proved by confocal laser scanning microscopy technique.


2018 ◽  
Vol 36 (4) ◽  
pp. 349-363 ◽  
Author(s):  
László Trif ◽  
Abdul Shaban ◽  
Judit Telegdi

AbstractSuitable application of techniques for detection and monitoring of microbiologically influenced corrosion (MIC) is crucial for understanding the mechanisms of the interactions and for selecting inhibition and control approaches. This paper presents a review of the application of electrochemical and surface analytical techniques in studying the MIC process of metals and their alloys. Conventional electrochemical techniques, such as corrosion potential (Ecorr), redox potential, dual-cell technique, polarization curves, electrochemical impedance spectroscopy (EIS), electrochemical noise (EN) analysis, and microelectrode techniques, are discussed, with examples of their use in various MIC studies. Electrochemical quartz crystal microbalance, which is newly used in MIC study, is also discussed. Microscopic techniques [scanning electron microscopy (SEM), environmental SEM (ESEM), atomic force microscopy (AFM), confocal laser microscopy (CLM), confocal laser scanning microscopy (CLSM), confocal Raman microscopy] and spectroscopic analytical methods [Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS)] are also highlighted. This review highlights the heterogeneous characteristics of microbial consortia and use of special techniques to study their probable effects on the metal substrata. The aim of this review is to motivate using a combination of new procedures for research and practical measurement and calculation of the impact of MIC and biofilms on metals and their alloys.


2019 ◽  
Vol 9 (7) ◽  
pp. 712-722 ◽  
Author(s):  
Yong Wang ◽  
Layun Deng ◽  
Zhihong Xiao ◽  
Xianjun Li ◽  
Youhua Fan ◽  
...  

The objective of this paper aimed to develop a novel method to prepare enhanced bamboo-based materials. Furfuryl alcohol (FA) was used as the modification agent with maleic anhydride (MA) as the catalyst. Different bamboo samples were prepared with different FA addition level (10 wt%, 20 wt% and 30 wt%). The furfurylated bamboo samples were characterized by confocal laser scanning microscopy (CLSM), Fourier transform infrared spectrometry (FTIR), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). Moreover, the physical and mechanical properties including weight percent gain (WPG), water uptake (WU), thickness swelling (TS), modulus of rupture (MOR), and modulus of elastic (MOE) were investigated in detail. Additionally, the decay resistance of pristine and furfurylated bamboo samples was also investigated. The results showed that FA resins were incorporated into bamboo and polymerized within cell walls. The WPG, WU, and TS were dependent on FA addition level. When the FA addition level reached 30 wt%, the physical properties were all improved significantly. However, due to acidic MA as the catalyst, MOR of furfurylated bamboo samples was enhanced only 2.5% while MOE was weakened. The thermal stability and decay resistance of furfurylated bamboo were all enhanced significantly compared to pristine bamboo. Especially, furfurylated bamboo treated with 30 wt% FA achieved Class I Strong Decay Resistance (<10%) with 5.3% of mass loss.


2021 ◽  
Author(s):  
Ata Aditya Wardana ◽  
Arisa Koga ◽  
Fumina Tanaka ◽  
Fumihiko Tanaka

Abstract A novel composite edible coating film was developed from 0.8% chitosan (CS) and 0.5% n sandalwood oil (SEO). Cellulose nanofibers (CNFs) were used as a stabilizer agent of oil-in-water Pickering emulsion. We found four typical groups of CNF level-dependent emulsion stabilization, including (1) unstable emulsion in the absence of CNFs; (2) unstable emulsion (0.006–0.21% CNFs); (3) stable emulsion (0.24–0.31% CNFs); and (4) regular emulsion with the addition of surfactant. Confocal laser scanning microscopy was performed to reveal the characteristics of droplet diameter and morphology. Antifungal tests against Botrytis cinerea and Penicillium digitatum, between emulsion coating stabilized with CNFs (CS-SEOpick) and CS or CS-SEO was tested. The effective concentration of CNFs (0.24%) may improve the performance of CS coating and maintain CS-SEO antifungal activity synergistically confirmed with a series of assays (in vitro, in vivo, and membrane integrity changes). The incorporation of CNFs contributed to improve the functional properties of CS and SEO-loaded CS including light transmission at UV and visible light wavelengths and tensile strength. Atomic force microscopy and scanning electron microscopy were employed to characterize the biocompatibility of each coating film formulation. Emulsion-CNF stabilized coating may have potential applications for active coating for fresh fruit commodities.


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