scholarly journals Refinement of Sustainable Polybutylene Adipate Terephthalate (PBAT) with Amorphous Hydrogenated Carbon Films (a-C:H) Revealing Film Instabilities Influenced by a Thickness-Dependent Change of sp2/sp3 Ratio

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1077 ◽  
Author(s):  
Torben Schlebrowski ◽  
Halima Acharchi ◽  
Barbara Hahn ◽  
Stefan Wehner ◽  
Christian B. Fischer
Keyword(s):  
Photoelectron Spectroscopy ◽  
Chemical Vapor ◽  
Carbon Films ◽  
Organic Polymer ◽  
X Ray ◽  
Angle Measurements ◽  
Dependent Change ◽  
Contact Angle Measurements ◽  
Diffuse Reflectance Infrared ◽  
Amorphous Hydrogenated Carbon

The increasing use of polymers is related to a growing disposal problem. Switching to biodegradable polymers such as polybutylene adipate terephthalate (PBAT) is a feasible possibility, but after industrial production of commercially available material PBAT is not suitable for every application. Therefore, surface refinements with amorphous hydrogenated carbon films (a-C:H) produced by plasma-assisted chemical vapor deposition (PE-CVD) changing the top layer characteristics are used. Here, 50 µm-thick PBAT films are coated with a-C:H layers up to 500 nm in 50 nm steps. The top surface sp2/sp3 bonding ratios are analyzed by X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS) both synchrotron-based. In addition, measurements using diffuse reflectance infrared Fourier transform spectroscopy (DRIFT) were performed for detailed chemical composition. Surface topography was analyzed by scanning electron microscopy (SEM) and the surface wettability by contact angle measurements. With increasing a-C:H layer thickness not only does the topography change but also the sp2 to sp3 ratio, which in combination indicates internal stress-induced phenomena. The results obtained provide a more detailed understanding of the mostly inorganic a-C:H coatings on the biodegradable organic polymer PBAT via in situ growth and stepwise height-dependent analysis.

scholarly journals Changing Contents of Carbon Hybridizations in Amorphous Hydrogenated Carbon Layers (a-C:H) on Sustainable Polyhydroxybutyrate (PHB) Exhibit a Significant Deterioration in Stability, Depending on Thickness

2019 ◽  
Vol 5 (3) ◽  
pp. 52 ◽  
Author(s):  
Torben Schlebrowski ◽  
Lucas Beucher ◽  
Hadi Bazzi ◽  
Barbara Hahn ◽  
Stefan Wehner ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Raw Materials ◽  
Chemical Vapor ◽  
Drift Spectroscopy ◽  
Significant Deterioration ◽  
X Ray ◽  
Diffuse Reflectance Infrared ◽  
X Ray Absorption ◽  
Amorphous Hydrogenated Carbon

PHB is a biodegradable polymer based on renewable raw materials that could replace synthetic polymers in many applications. A big advantage is the resulting reduction of the waste problem, as well as the conservation of fossil resources. To arrange it for various applications, the surface is arranged by plasma-enhanced chemical vapor deposition (PECVD) with amorphous hydrogenated carbon layers (a-C:H). Here, on a 50 µm thick PHB-foil, a-C:H layers of different thicknesses (0–500 nm) were deposited in 50 nm steps. Surface topography was investigated by scanning electron microscopy (SEM), chemical composition by diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy and wettability checked by contact angle. In addition, layers were examined by synchrotron supported X-ray photoelectron spectroscopy (XPS) and near edge X-ray absorption fine structure (NEXAFS), which revealed thickness dependent changes of the sp2/sp3 ratio. With increasing thickness, even the topography changes show internal, stress-induced phenomena. The results obtained provide a more detailed understanding of the predominantly inorganic a-C:H coatings on (bio)polymers via in situ growth.

scholarly journals Plasma Supported Deposition of Amorphous Hydrogenated Carbon (a-C:H) on Polyamide 6: Determining Interlayer Completion and Dehydrogenation Effects during Layer Growth

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1886
Author(s):  
Torben Schlebrowski ◽  
Henriette Lüber ◽  
Lucas Beucher ◽  
Melanie Fritz ◽  
Youssef Benjillali ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Chemical Vapor ◽  
Polyamide 6 ◽  
Carbon Layer ◽  
Layer Growth ◽  
Ex Situ ◽  
X Ray ◽  
Force Microscopy ◽  
Angle Measurements ◽  
Diffuse Reflectance Infrared

Polyamide 6 (PA6) is a commonly used material in many different sectors of modern industry. Herein, PA6 samples were coated with amorphous carbon layers (a-C:H) with increasing thickness up to 2 µm using radio frequency plasma enhanced chemical vapor deposition for surface adjustment. The morphology of the carbon coatings was inspected by ex situ atomic force microscopy and scanning electron microscopy. Surface wettability was checked by contact angle measurements. The chemical composition was analyzed using the surface sensitive synchrotron X-ray-based techniques near-edge X-ray absorption fine structure and X-ray photoelectron spectroscopy, supported by diffuse reflectance infrared Fourier transform spectroscopy. Particular attention was paid to the coating interval from 0 to 100 nm, to specify the interlayer thickness between the PA6 polymer and a-C:H coating, and the region between 1000 and 2000 nm, where dehydrogenation of the a-C:H layer occurs. The interlayer is decisive for the linkage of the deposited carbon layer on the polymer: the more pronounced it is, the better the adhesion. The thickness of the interlayer could be narrowed down to 40 nm in all used methods, and the dehydrogenation process takes place at a layer thickness of 1500 nm.

Preparation and Characterization of Chromium Containing amorphous Hydrogenated Carbon Films (A-C:H/Cr)

1995 ◽  
Vol 388 ◽  
Author(s):  
R. Gampp ◽  
P. Gantenbein ◽  
P. Oelhafen
Keyword(s):  
Chromium Carbide ◽  
Photoelectron Spectroscopy ◽  
Chemical Vapor ◽  
Carbon Films ◽  
Rf Plasma ◽  
Silicon Substrates ◽  
Amorphous Hydrogenated Carbon ◽  
High Chemical Stability

AbstractChromium containing amorphous hydrogenated carbon films (a-C:H/Cr) were prepared in a process that combines rf plasma activated chemical vapor deposition of methane and magnetron sputtering of a chromium target. During the deposition the silicon substrates were kept at 200°C and dc biased at -200 V in order to obtain films with high chemical stability which is required for the application as solar selective surfaces. the films with different Cr concentrations (5 to 49 at.%) were characterized by in situ x-ray photoelectron spectroscopy (XPS). Up to 40 at.%, chromium proves to be built into the cermet-like films in the form of chromium carbide clusters. above 40 at.%, chromium is partly metallic. a modification of the a-C:H matrix in the vicinity of the chromium carbide clusters has been observed.

scholarly journals Effect of Al (III) Ions on the Separation of Cassiterite and Clinochlore Through Reverse Flotation

Minerals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 347 ◽  
Author(s):  
Yumeng Chen ◽  
Xiong Tong ◽  
Dongxia Feng ◽  
Xian Xie
Keyword(s):  
Contact Angle ◽  
Photoelectron Spectroscopy ◽  
Interaction Mechanism ◽  
Reverse Flotation ◽  
X Ray ◽  
Angle Measurements ◽  
Mineral Flotation ◽  
Contact Angle Measurements ◽  
Flotation Performance ◽  
Hydrophobic Clay

Most hydrophobic clay minerals, such as clinochlore, are known to cause problems in the recovery of cassiterite. In this study, a new reagent scheme, i.e., sodium oleate (NaOL) as a collector and Al (III) ions as a depressant, for reverse flotation separation of cassiterite and clinochlore was investigated. The flotation performance and interaction mechanism were studied by microflotation tests, adsorption tests, contact angle measurements, and X-ray photoelectron spectroscopy (XPS) analysis. Results of single mineral flotation experiments showed that NaOL had a different flotation performance on cassiterite and clinochlore, and the addition of Al (III) ions could selectively inhibit the floatability of cassiterite. Reverse flotation tests performed on mixed minerals indicated that the separation of cassiterite and clinochlore could be achieved in the presence of NaOL and Al (III) ions. Adsorption experiments demonstrated that Al (III) ions hindered the adsorption of NaOL on cassiterite surfaces but exerted little influence on the adsorption of NaOL on clinochlore surfaces. Results of contact angle measurements indicated that Al (III) ions could impede the hydrophobization process of cassiterite in NaOL solution. XPS results showed that aluminum species were adsorbed onto the cassiterite surfaces through the interaction with O sites.

scholarly journals Ice-Templated Cellulose Nanofiber Filaments as a Reinforcement Material in Epoxy Composites

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 490
Author(s):  
Tuukka Nissilä ◽  
Jiayuan Wei ◽  
Shiyu Geng ◽  
Anita Teleman ◽  
Kristiina Oksman
Keyword(s):  
Photoelectron Spectroscopy ◽  
Cellulose Nanofibers ◽  
Chemical Vapor ◽  
Cellulose Nanofiber ◽  
X Ray ◽  
The Matrix ◽  
Wide Availability ◽  
Spectroscopy Studies ◽  
Diffuse Reflectance Infrared ◽  
Cellulose Nanocomposites

Finding renewable alternatives to the commonly used reinforcement materials in composites is attracting a significant amount of research interest. Nanocellulose is a promising candidate owing to its wide availability and favorable properties such as high Young’s modulus. This study addressed the major problems inherent to cellulose nanocomposites, namely, controlling the fiber structure and obtaining a sufficient interfacial adhesion between nanocellulose and a non-hydrophilic matrix. Unidirectionally aligned cellulose nanofiber filament mats were obtained via ice-templating, and chemical vapor deposition was used to cover the filament surfaces with an aminosilane before impregnating the mats with a bio-epoxy resin. The process resulted in cellulose nanocomposites with an oriented structure and a strong fiber–matrix interface. Diffuse reflectance infrared Fourier transform and X-ray photoelectron spectroscopy studies revealed the presence of silane on the filaments. The improved interface, resulting from the surface treatment, was observable in electron microscopy images and was further confirmed by the significant increase in the tan delta peak temperature. The storage modulus of the matrix could be improved up to 2.5-fold with 18 wt% filament content and was significantly higher in the filament direction. Wide-angle X-ray scattering was used to study the orientation of cellulose nanofibers in the filament mats and the composites, and the corresponding orientation indices were 0.6 and 0.53, respectively, indicating a significant level of alignment.

A Multi-Technique Analysis of MOCVD- Grown Lead Lanthanum Titanate (Pb1−xLax)TiO3 Thin Films on Quartz Substrates

1997 ◽  
Vol 493 ◽  
Author(s):  
H. Y. Chen ◽  
J. Lin ◽  
K. L. Tan ◽  
Z. C. Feng ◽  
B. S. Kwak ◽  
...  
Keyword(s):  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Chemical Vapor ◽  
Gradual Change ◽  
X Ray Diffraction ◽  
Raman Scattering Spectroscopy ◽  
X Ray ◽  
Lanthanum Titanate ◽  
Diffuse Reflectance Infrared ◽  
Quartz Substrates

AbstractA series of Lead lanthanum titanate (Pb1−xLax)TiO3 thin films with different compositions of x = 0 − 0.33 have been grown on fused quartz substrates by metalorganic chemical vapor deposition (MOCVD) and analyzed by a variety of techniques including X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Raman scattering spectroscopy (RSS) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) techniques. XPS results confirmed the film composition of (Pb1−x Lax)TiO3 and lanthanum enrichment in top surface layers. XRD indicates a preferred (100) orientation for the films with x values of 0.05–0.17, while the films with x values above 0.32 have randomly distributed orientations. A gradual change in the crystal structure from tetragonal to cubic arrangement with increasing La composition is noted. XPS data also show the variation of Ti-O, Pb-0 and La-0 bonding with the change in the La composition. The stretching vibrations corresponding to these oxygen related bonding are observed by DRIFT at 667, 826, 936 and 529 cm−1 respectively. This combined investigation on epitaxial PLT films may enhance our understanding of the ferroelectric PLT materials.

The Effects of the Self-Assembly Time on the Preparation of Lanthanum-Based Thin Films on Sulfonated 3-Mercaptopropyl Trimethoxysilane

2012 ◽  
Vol 164 ◽  
pp. 284-288
Author(s):  
Tao Bai ◽  
Xian Hua Cheng
Keyword(s):  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Self Assembly ◽  
Self Assembled Monolayer ◽  
X Ray ◽  
Assembly Time ◽  
Force Microscopy ◽  
Angle Measurements ◽  
Atomic Force ◽  
Contact Angle Measurements

Lanthanum-based thin films are deposited on the oxidized 3-mercaptopropyl trimethoxysilane self-assembled monolayer (MPTS-SAM) based on the chemisorption of the sulfonic group. The surface energy, chemical composition, phase transformation and surface morphology of the films are analyzed by using contact angle measurements, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The experimental results indicate that the lanthanum-based thin films are absorbed on oxidized MPTS-SAM and lanthanum element with different oxidation states exists in the thin films deposited on the surface of self-assembly monolayers. The content of lanthanum on the oxidized MPTS-SAM increases with the extension of the assembly time and the rare earth reached saturation when the time was 6h.

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