scholarly journals Synthesis and characterization of hydrophobic, ultra-fine fibres based on an organic–inorganic nanocomposite containing a polyimide functionality

2019 ◽  
Vol 27 (5) ◽  
pp. 268-278
Author(s):  
Christian Schramm ◽  
Beate Rinderer ◽  
Richard Tessadri
Keyword(s):  
Fibre Diameter ◽  
Precursor Solution ◽  
Amic Acid ◽  
Water Contact ◽  
X Ray ◽  
Angle Measurements ◽  
Fine Fibre ◽  
Contact Angle Measurements ◽  
Electrospinning Method

Ultra-thin polyimide fibres were fabricated by means of the electrospinning method by using precursor solutions consisting of the organotrialkoxysilanes (3-triethoxysilylpropyl)succinic anhydride (TESP-SA), (3-amino)propyltriethoxysilane (APTES), tetraethoxysilane (TEOS) and methyltriethoxysilane (MTEOS). TESP-SA and APTES were reacted to the corresponding poly(amic)acid (PAA) in an aqueous medium which was electrospun at 15 kV and at a tip to collector distance of 15 cm. TEOS and MTEOS were also incorporated into the precursor solution to modify the surface properties of the ultra-fine fibre mat. The fibre diameter distributions of the as-prepared PAA fibres were measured. The PAA fibres were thermally treated at 220°C resulting in the formation of an organic–inorganic hybrid polyimide fibre mat with ladder-like structure, as could be shown by Fourier transform infrared spectroscopy and X-ray powder diffraction. The ultra-fine fibre assemblies were also characterized by means of scanning electron microscopy, thermogravimetric analysis and water contact angle measurements.

scholarly journals Wood-Mimicking Bio-Based Biporous Polymeric Materials with Anisotropic Tubular Macropores

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2692
Author(s):  
Vierajitha Srikanthan ◽  
Olivier Pitois ◽  
Philippe Coussot ◽  
Benjamin Le Droumaguet ◽  
Daniel Grande
Keyword(s):  
Structural Parameters ◽  
Crosslinking Agent ◽  
Polymeric Materials ◽  
Material Surface ◽  
Water Contact ◽  
X Ray ◽  
Angle Measurements ◽  
Flow Transport ◽  
Contact Angle Measurements ◽  
Physical Phenomena

Understanding physical phenomena related to fluid flow transport in plants and especially through wood is still a major challenge for the scientific community. To this end, we have focused our attention on the design of wood-mimicking polymeric architectures through a strategy based on the double porogen templating approach which relies on the use of two distinct types of porogens, namely aligned nylon threads and a porogenic solvent, to produce macro- and nanoporosity levels, respectively. A bio-based phenolic functional monomer, i.e., vanillin methacrylate, was employed to mimic either hard wood or soft wood. Upon free-radical polymerization with a crosslinking agent in the presence of both types of porogenic agents, followed by their removal, biporous materials with anistotropic tubular macropores surrounded by a nanoporous matrix were obtained. They were further fully characterized in terms of porosity and chemical composition via mercury intrusion porosimetry, scanning electron microscopy and X-ray microtomography. It was demonstrated that the two porosity levels could be independently tuned by varying structural parameters. Further, the possibility to chemically modify the pore surface and thus to vary the material surface properties was successfully demonstrated by reductive amination with model compounds via Raman spectroscopy and water contact angle measurements.

scholarly journals Electrochemical Aspects of a Nitrogen-Doped Pseudo-Graphitic Carbon Material: Resistance to Electrode Fouling by Air-Aging and Dopamine Electro-Oxidation

2020 ◽  
Vol 6 (4) ◽  
pp. 68
Author(s):  
Kailash Hamal ◽  
Jeremy May ◽  
Haoyu Zhu ◽  
Forrest Dalbec ◽  
Elena Echeverria ◽  
...  
Keyword(s):  
Pyrolytic Graphite ◽  
X Ray Diffraction ◽  
Water Contact ◽  
X Ray ◽  
Nitrogen Doped ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Electro Oxidation ◽  
The University ◽  
University Of Idaho

The nitrogen-doped form of GUITAR (pseudo-Graphite from the University of Idaho Thermalized Asphalt Reaction) was examined by X-ray photoelectron, Raman, and X-ray diffraction spectroscopies and cyclic voltammetry (CV). Electrochemical studies indicate that N-GUITAR exhibits significant resistance to fouling by adsorption and by passivation. Unlike other carbon materials, it maintains fast heterogenous electron transfer (HET) kinetics with Fe(CN)63−/4− with exposure to air. The CV peak potential separation (ΔEp) of 66 mV increased to 69 mV in 3 h vs. 67 to 221 mV for a highly oriented pyrolytic graphite (HOPG) electrode. Water contact angle measurements indicate that N-GUITAR was able to better maintain a hydrophilic state during the 3-h exposure, going from 55.8 to 70.4° while HOPG increased from 63.8 to 80.1°. This indicates that N-GUITAR better resisted adsorption of volatile organic compounds. CV studies of dopamine also indicate N-GUITAR is resistant to passivation. The ΔEp for the dopamine/o-dopaminoquinone couple is 83 mV indicating fast HET rates. This is reflected in the peak current ratios for the oxidation and reduction processes of 1.3 indicating that o-dopaminoquinone is not lost to passivation processes. This ratio along with the minimal signal attenuation is the best reported in literature.

scholarly journals Preparation and Characterization of Chitosan/Agar Blended Films: Part 2. Thermal, Mechanical, and Surface Properties

2012 ◽  
Vol 9 (2) ◽  
pp. 510-516 ◽  
Author(s):  
Esam A. Elhefian ◽  
Mohamed Mahmoud Nasef ◽  
Abdul Hamid Yahaya
Keyword(s):  
Gravimetric Analysis ◽  
Thermal Gravimetric ◽  
Water Contact ◽  
Elongation At Break ◽  
Angle Measurements ◽  
Static Water Contact Angle ◽  
Contact Angle Measurements ◽  
Static Water ◽  
Thermal Stability Of

Chitosan/agar (CS/AG) films were prepared by blending different proportions of chitosan and agar (considering chitosan as the major component) in solution forms. The thermal stability of the blended films was studied using thermal gravimetric analysis (TGA). It was revealed that chitosan and agar form a compatible blend. Studying the mechanical properties of the films showed a decrease in the tensile strength and elongation at break with increasing agar content. Blending of agar with chitosan at all proportions was found to form hydrogel films with enhanced swelling compared to the pure chitosan one. Static water contact angle measurements confirmed the increasing affinity of the blended films towards water suggesting that blending of agar with chitosan improves the wettability of the obtained films.

Characterization of 3C-SiC (100) as a platform for detecting the onset of acute myocardial infarction (AMI)

2012 ◽  
Vol 1433 ◽  
Author(s):  
Alexandra Oliveros ◽  
Anthony Guiseppi-Elie ◽  
Mark Jaroszeski ◽  
Stephen E. Saddow
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Contact Angle ◽  
Layer Formation ◽  
Water Contact ◽  
Force Microscopy ◽  
Angle Measurements ◽  
Atomic Force ◽  
Contact Angle Measurements

ABSTRACTIn this work we describe the characterization of anti-myoglobin immobilization on 3C-SiC (100) by means of surface modification with 3-aminopropyltriethoxysilane (APTES). Surface water contact angle measurements were used to compare the wettability of 3C-SiC (100) before (16 ±3°) and after APTES layer formation (61 ±1°). Atomic force microscopy (AFM) was used to confirm the homogenous formation of APTES and anti-myoglobin immobilization with EDC-sulfo NHS coupling. For the APTES surfaces no significant change in the surface roughness was obtained whereas with anti-myoglobin surfaces, particles on the order of ∼60 nm in diameter with a globular shape were observed.

scholarly journals Preparation and Characterization of Chitosan/Poly(Vinyl Alcohol) Blended Films: Mechanical, Thermal and Surface Investigations

2011 ◽  
Vol 8 (1) ◽  
pp. 91-96 ◽  
Author(s):  
Esam A. El-Hefian ◽  
Mohamed Mahmoud Nasef ◽  
Abdul Hamid Yahaya
Keyword(s):  
Contact Angle ◽  
Poly Vinyl Alcohol ◽  
Scanning Calorimetry ◽  
Water Contact ◽  
Elongation At Break ◽  
Angle Measurements ◽  
Static Water Contact Angle ◽  
Contact Angle Measurements ◽  
Static Water

In this study, blends of chitosan (CS) and polyvinyl alcohol (PVA) (CS/PVA) having various proportions were prepared and characterized by universal mechanical tester, the differential scanning calorimetry (DSC) and contact angle measurements. Studying the mechanical properties of the films showed that blending improved the tensile strength, which increased with increasing PVA content up to 40% while the elongation% at break of the blends was decreased compared to that of the pure components. The obtained results of DSC suggested that some interaction between chitosan and PVA mostly took place. Static water contact angle measurements showed an improvement in the wettability of the obtained films.

scholarly journals Photocatalytic degradation of a basic dye in water by nanostructured HPEI/TiO2 containing membranes

Water SA ◽  
2020 ◽  
Vol 46 (3 July) ◽  
Author(s):  
Penny Mathumba ◽  
Khona Maziya ◽  
Alex T Kuvarega ◽  
Langelihle N Dlamini ◽  
Soraya P Malinga
Keyword(s):  
Water Flux ◽  
Flux Analysis ◽  
Water Contact ◽  
X Ray ◽  
Force Microscopy ◽  
Angle Measurements ◽  
Atomic Force ◽  
Contact Angle Measurements ◽  
Pes Membrane ◽  
By Products

A photocatalytically active membrane was synthesized through the embedding of HPEI/TiO2 nanocomposite in PES membrane for the removal of methyl orange (MO) dye from water. Membranes were characterized using scanning electron microscopy coupled with energy dispersive X-ray, atomic force microscopy, water contact angle measurements and water flux analysis.  PES/HPEI/TiO2 membranes showed improved hydrophilicity and were effective in the photodegradation of MO. The reaction rate for MO degradation was 11.6 x 10−3∙min−1, and the degradation was accompanied by the generation of sulphate ions as degradation by-products.

Nanostructured Polymer Brushes With Reversibly Changing Properties

2002 ◽  
Vol 727 ◽  
Author(s):  
Denys Usov ◽  
Manfred Stamm ◽  
Sergiy Minko ◽  
Christian Froeck ◽  
Andreas Scholl ◽  
...  
Keyword(s):  
Polymer Brushes ◽  
Phase Segregation ◽  
Water Contact ◽  
Angle Measurements ◽  
Nanostructured Polymer ◽  
Contact Angle Measurements ◽  
Vertical Segregation ◽  
Oxygen Plasma Etching ◽  
Grafting From ◽  
Photoemission Electron

AbstractWe investigated the interplay between different mechanisms of the lateral and vertical segregation in the synthesized via “grafting from” approach symmetric A/B (where A and B are poly(styrene-co-2,3,4,5,6-pentafluorostyrene) and poly(methylmethacrylate), respectively) polymer brushes upon exposure to different solvents. We used X-ray photoemission electron spectroscopy and microscopy (X-PEEM), AFM, water contact angle measurements, and oxygen plasma etching to study morphology of the brushes. The ripple morphology after toluene (nonselective solvent) revealed elongated lamellar-like domains of A and B polymers alternating across the surface. The dimple-A morphology consisting of round clusters of the polymer A was observed after acetone (selective solvent for B). The top layer was enriched with the polymer B showing that the brush underwent both the lateral and vertical phase segregation. A qualitative agreement with predictions of SCF theory was found.

scholarly journals Epoxy/alumina composite coating on welded steel 316L with excellent wear and anticorrosion properties

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Maryama Hammi ◽  
Younes Ziat ◽  
Zakaryaa Zarhri ◽  
Charaf Laghlimi ◽  
Abdelaziz Moutcine
Keyword(s):  
Electrochemical Behaviour ◽  
Sem Analysis ◽  
Water Contact ◽  
Welded Steel ◽  
Melted Zone ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Alumina Composite ◽  
The Cost ◽  
Good Contrast

AbstractThe main purpose of this study is to elaborate anticorrosive coatings for the welded steel 316L, since this later is widely used in industrial field. Hence, within this work we have studied the electrochemical behaviour of different zones of the welded steel 316 in 1 M HCl media. The macrography study of the welded steel has revealed the different areas with a good contrast. We have stated three different zones, namely; melted zone (MZ), heat affected zone (HAZ) and base metal zone (BM). Impedance studies on welded steel 316L were conducted in 1 M HCl solution, coating of Epoxy/Alumina composite was applied on different zones, in order to reveal the anti-corrosion efficiency in each zone. Scanning electron microscopy (SEM) analysis was undertaken in order to check how far the used coating in such aggressive media protects the studied zones and these findings were assessed by water contact angle measurements. The choice of this coating is based on the cost and the safety. We concluded that the Epoxy/Alumina composite has a good protecting effect regarding welded steel in aggressive media.

scholarly journals PLA-Based Hybrid and Composite Electrospun Fibrous Scaffolds as Potential Materials for Tissue Engineering

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Anna Magiera ◽  
Jarosław Markowski ◽  
Elzbieta Menaszek ◽  
Jan Pilch ◽  
Stanislaw Blazewicz
Keyword(s):  
Tissue Engineering ◽  
Mechanical Tests ◽  
Hybrid Structures ◽  
Poly Lactic Acid ◽  
Electrospinning Technique ◽  
Water Contact ◽  
Human Osteoblasts ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Normal Human

The aim of the study was to manufacture poly(lactic acid)- (PLA-) based nanofibrous nonwovens that were modified using two types of modifiers, namely, gelatin- (GEL-) based nanofibres and carbon nanotubes (CNT). Hybrid nonwovens consisting of PLA and GEL nanofibres (PLA/GEL), as well as CNT-modified PLA nanofibres with GEL nanofibres (PLA + CNT/GEL), in the form of mats, were manufactured using concurrent-electrospinning technique (co-ES). The ability of such hybrid structures as potential scaffolds for tissue engineering was studied. Both types of hybrid samples and one-component PLA and CNTs-modified PLA mats were investigated using scanning electron microscopy (SEM), water contact angle measurements, and biological and mechanical tests. The morphology, microstructure, and selected properties of the materials were analyzed. Biocompatibility and bioactivity in contact with normal human osteoblasts (NHOst) were studied. The coelectrospun PLA and GEL nanofibres retained their structures in hybrid samples. Both types of hybrid nonwovens were not cytotoxic and showed better osteoinductivity in comparison to scaffolds made from pure PLA. These samples also showed significantly reduced hydrophobicity compared to one-component PLA nonwovens. The CNT-contained PLA nanofibres improved mechanical properties of hybrid samples and such a 3D system appears to be interesting for potential application as a tissue engineering scaffold.

Sign in / Sign up

Export Citation Format

Share Document