scholarly journals Enhancing iCVD Modification of Electrospun Membranes for Membrane Distillation Using a 3D Printed Scaffold

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2074
Author(s):  
Nicole Beauregard ◽  
Mustafa Al-Furaiji ◽  
Garrett Dias ◽  
Matthew Worthington ◽  
Aravind Suresh ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Membrane Distillation ◽  
Vapor Transport ◽  
High Porosity ◽  
Fiber Network ◽  
Conformal Coating ◽  
Initiated Chemical Vapor Deposition ◽  
Electrospun Membranes ◽  
3D Printed ◽  
Coating Procedure

Electrospun membranes have shown promise for use in membrane distillation (MD) as they exhibit exceptionally low vapor transport. Their high porosity coupled with the occasional large pore can make them prone to wetting. In this work, initiated chemical vapor deposition (iCVD) is used to modify for electrospun membranes with increased hydrophobicity of the fiber network. To demonstrate conformal coating, we demonstrate the approach on intrinsically hydrophilic electrospun fibers and render the fibers suitable for MD. We enable conformal coating using a unique coating procedure, which provides convective flow of deposited polymers during iCVD. This is made possible by using a 3D printed scaffold, which changed the orientation of the membrane during the coating process. The new coating orientation allows both sides as well as the interior of the membrane to be coated simultaneously and reduced the coating time by a factor of 10 compared to conventional CVD approaches. MD testing confirmed the hydrophobicity of the material as 100% salt rejections were obtained.

scholarly journals Conformal Coating of Powder by Initiated Chemical Vapor Deposition on Vibrating Substrate

Pharmaceutics ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 904
Author(s):  
Katrin Unger ◽  
Anna Maria Coclite
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Magnesium Citrate ◽  
Conformal Coating ◽  
Initiated Chemical Vapor Deposition ◽  
Cohesive Powder ◽  
Release Curve ◽  
Poly Ethylene ◽  
Cohesive Powders

Encapsulation of pharmaceutical powders within thin functional polymer films is a powerful and versatile method to modify drug release properties. Conformal coating over the complete surface of the particle via chemical vapor deposition techniques is a challenging task due to the compromised gas–solid contact. In this study, an initiated chemical vapor deposition reactor was adapted with speakers and vibration of particles was achieved by playing AC/DC’s song “Thunderstruck” to overcome the above-mentioned problem. To show the possibilities of this method, two types of powder of very different particle sizes were chosen, magnesium citrate (3–10 µm, cohesive powder) and aspirin (100–500 µm, good flowability), and coated with poly-ethylene-glycol-di-methacrylate. The release curve of coated magnesium citrate powder was retarded compared to uncoated powder. However, neither changing the thickness coating nor vibrating the powder during the deposition had influence on the release parameters, indicating, that cohesive powders cannot be coated conformally. The release of coated aspirin was as well retarded as compared to uncoated aspirin, especially in the case of the powder that vibrated during deposition. We attribute the enhancement of the retarded release to the formation of a conformal coating on the aspirin powder.

scholarly journals Surface functionalization of 3D-printed plastics via initiated chemical vapor deposition

2017 ◽  
Vol 8 ◽  
pp. 1629-1636 ◽  
Author(s):  
Christine Cheng ◽  
Malancha Gupta
Keyword(s):  
Chemical Vapor Deposition ◽  
3D Printing ◽  
Vapor Deposition ◽  
Photoelectron Spectroscopy ◽  
Chemical Vapor ◽  
Acrylonitrile Butadiene Styrene ◽  
Poly Lactic Acid ◽  
Material Strength ◽  
Initiated Chemical Vapor Deposition ◽  
3D Printed

3D printing is a useful fabrication technique because it offers design flexibility and rapid prototyping. The ability to functionalize the surfaces of 3D-printed objects allows the bulk properties, such as material strength or printability, to be chosen separately from surface properties, which is critical to expanding the breadth of 3D printing applications. In this work, we studied the ability of the initiated chemical vapor deposition (iCVD) process to coat 3D-printed shapes composed of poly(lactic acid) and acrylonitrile butadiene styrene. The thermally insulating properties of 3D-printed plastics pose a challenge to the iCVD process due to large thermal gradients along the structures during processing. In this study, processing parameters such as the substrate temperature and the filament temperature were systematically varied to understand how these parameters affect the uniformity of the coatings along the 3D-printed objects. The 3D-printed objects were coated with both hydrophobic and hydrophilic polymers. Contact angle goniometry and X-ray photoelectron spectroscopy were used to characterize the functionalized surfaces. Our results can enable the use of iCVD to functionalize 3D-printed materials for a range of applications such as tissue scaffolds and microfluidics.

Multiple Donors in Zinc Oxide Substrates

2002 ◽  
Vol 719 ◽  
Author(s):  
K. Thonke ◽  
N. Kerwien ◽  
A. Wysmolek ◽  
M. Potemski ◽  
A. Waag ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Chemical Vapor ◽  
Binding Energies ◽  
Vapor Transport ◽  
Chemical Vapor Transport ◽  
Oxide Substrates ◽  
Multiple Donors ◽  
Major Donors ◽  
Available Zinc ◽  
Transport Technique

AbstractWe investigate by photoluminescence (PL) nominally undoped, commercially available Zinc Oxide substrates (from Eagle Picher) grown by seeded chemical vapor transport technique in order to identify residual donors and acceptors. In low temperature PL spectra the dominant emission comes from the decay of bound exciton lines at around 3.36 eV. Zeeman measurements allow the identification of the two strongest lines and some weaker lines in-between as donorrelated. From the associated two-electron satellite lines binding energies of the major donors of 48 meV and 55 meV, respectively, can be deduced.

scholarly journals Triple-Layer Nanocomposite Membrane Prepared by Electrospinning Based on Modified PES with Carbon Nanotubes for Membrane Distillation Applications

Membranes ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 15 ◽  
Author(s):  
Mohamed R. Elmarghany ◽  
Ahmed H. El-Shazly ◽  
Saeid Rajabzadeh ◽  
Mohamed S. Salem ◽  
Mahmoud A. Shouman ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Vinylidene Fluoride ◽  
Bulk Material ◽  
Total Porosity ◽  
Surface Hydrophobicity ◽  
Membrane Distillation ◽  
Nanocomposite Membrane ◽  
High Porosity ◽  
Triple Layer ◽  
Layer Membrane

In this work, a novel triple-layer nanocomposite membrane prepared with polyethersulfone (PES)/carbon nanotubes (CNTs) as the primary bulk material and poly (vinylidene fluoride-co-hexafluoro propylene) (PcH)/CNTs as the outer and inner surfaces of the membrane by using electrospinning method is introduced. Modified PES with CNTs was chosen as the bulk material of the triple-layer membrane to obtain a high porosity membrane. Both the upper and lower surfaces of the triple-layer membrane were coated with PcH/CNTs using electrospinning to get a triple-layer membrane with high total porosity and noticeable surface hydrophobicity. Combining both characteristics, next to an acceptable bulk hydrophobicity, resulted in a compelling membrane for membrane distillation (MD) applications. The prepared membrane was utilized in a direct contact MD system, and its performance was evaluated in different salt solution concentrations, feed velocities and feed solution temperatures. The results of the prepared membrane in this study were compared to those reported in previously published papers. Based on the evaluated membrane performance, the triple-layer nanocomposite membrane can be considered as a potential alternative with reasonable cost, relative to other MD membranes.

scholarly journals Evolution of reduction process from tungsten oxide to ultrafine tungsten powder via hydrogen

2021 ◽  
Vol 40 (1) ◽  
pp. 171-177
Author(s):  
Yue Wang ◽  
Ben Fu Long ◽  
Chun Yu Liu ◽  
Gao An Lin
Keyword(s):  
Surface Morphology ◽  
Tungsten Oxide ◽  
Tungsten Powder ◽  
Reduction Process ◽  
Chemical Vapor ◽  
Transition Process ◽  
Vapor Transport ◽  
Fibrous Structure ◽  
Chemical Vapor Transport ◽  
Oxide Particles

Abstract Herein, the evolution of reduction process of ultrafine tungsten powder in industrial conditions was investigated. The transition process of morphology and composition was examined via SEM, XRD, and calcination experiments. The results show that the reduction sequence of WO2.9 was WO2.9 → WO2.72 → WO2 → W on the surface, but WO2.9 → WO2 → W inside the oxide particles. With the aid of chemical vapor transport of WO x (OH) y , surface morphology transformed into rod-like, star-shaped cracking, floret, irregularly fibrous structure, and finally, spherical tungsten particles.

Exploring the potential usage of 3D printed membranes combined with PVDF coating in direct contact membrane distillation

Desalination ◽  
2021 ◽  
pp. 115134
Author(s):  
Miaomiao Tian ◽  
Hellen De Coninck ◽  
Junyong Zhu ◽  
Yatao Zhang ◽  
Shushan Yuan ◽  
...  
Keyword(s):  
Direct Contact ◽  
Membrane Distillation ◽  
Direct Contact Membrane Distillation ◽  
3D Printed

scholarly journals Initiated Chemical Vapor Deposition (iCVD) Functionalized Polylactic Acid–Marine Algae Composite Patch for Bone Tissue Engineering

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 186
Author(s):  
Wiebke Reichstein ◽  
Levke Sommer ◽  
Salih Veziroglu ◽  
Selin Sayin ◽  
Stefan Schröder ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Chemical Vapor Deposition ◽  
Bone Tissue Engineering ◽  
Bone Tissue ◽  
Vapor Deposition ◽  
Marine Algae ◽  
Chemical Vapor ◽  
Human Osteoblasts ◽  
Composite Patch ◽  
Initiated Chemical Vapor Deposition

The current study aimed to describe the fabrication of a composite patch by incorporating marine algae powders (MAPs) into poly-lactic acid (PLA) for bone tissue engineering. The prepared composite patch was functionalized with the co-polymer, poly (2-hydroxyethyl methacrylate-co-ethylene glycol dimethacrylate) (p(HEMA-co-EGDMA)) via initiated chemical vapor deposition (iCVD) to improve its wettability and overall biocompatibility. The iCVD functionalized MAP–PLA composite patch showed superior cell interaction of human osteoblasts. Following the surface functionalization by p(HEMA-co-EGDMA) via the iCVD technique, a highly hydrophilic patch was achieved without tailoring any morphological and structural properties. Moreover, the iCVD modified composite patch exhibited ideal cell adhesion for human osteoblasts, thus making the proposed patch suitable for potential biomedical applications including bone tissue engineering, especially in the fields of dentistry and orthopedy.

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