Refinement of Nanoporous Copper with Poly(vinyl alcohol) During Dealloying Amorphous Mg65Cu25Y10 Precursors

2020 ◽  
Vol 20 (6) ◽  
pp. 3568-3575
Author(s):  
Zhen-Hua Dan ◽  
Li-Jun Xu ◽  
Yue-Cheng Dong ◽  
Ying Wang ◽  
Feng-Xiang Qin ◽  
...  
Keyword(s):  
Polymer Surface ◽  
Selective Dissolution ◽  
Polymerization Process ◽  
Poly Vinyl Alcohol ◽  
Small Scale ◽  
Nanoporous Copper ◽  
Reduced Rate ◽  
20 Nm ◽  
Polymer Surface Layer ◽  
Ligament Size

Ultrafine nanoporous copper (UNP Cu) with a characteristic pore size of about 12 nm and a ligament size of about 14 nm was fabricated from amorphous Mg65Cu25Y10 precursor alloys after dealloying in a 0.1 M H2SO4 solution modified by poly(vinyly alcohol) polymers with a molecular weight of 105000 g/mol (PVA-124). The suppression of the surface diffusion from PVA-124 reduced the size of the nanopores and ligaments to 20 nm when the concentration of the added PVA-124 exceeded 0.1 g L−1. When the concentration of the added PVA-124 exceeded 2 g L−1, PVA-124 triggered the polymerization process. The resultant polymer surface layer on the fcc Cu ligaments was shown to reduce the rate of selective dissolution. It was also shown that extending the immersion time resulted in a suppression of coarsening. The introduction of PVA-124 polymer into acids resulted in a higher viscosity of the dealloying solutions, particularly when the concentration of PVA-124 was higher than 1.0 g L−1. This viscosity was shown not only to reduced rate of diffusion of Cu adatoms in PVA-124 solutions, but also forced the accumulation of Cu adatoms to form small scale UNP Cu.

Simple and non-toxic fabrication of poly(vinyl alcohol)-patterned polymer surface for the formation of cell patterns

2014 ◽  
Vol 316 ◽  
pp. 179-186 ◽  
Author(s):  
In-Tae Hwang ◽  
Yu-Ran Jin ◽  
Min-Suk Oh ◽  
Chan-Hee Jung ◽  
Jae-Hak Choi
Keyword(s):  
Vinyl Alcohol ◽  
Polymer Surface ◽  
Poly Vinyl Alcohol ◽  
Cell Patterns

Cellulose acetate/poly(vinyl alcohol) hybrid fibrous mat containing tetracycline hydrochloride and phenytoin sodium: Morphology, drug release, antibacterial, and cell culture studies

2018 ◽  
Vol 33 (6) ◽  
pp. 597-611 ◽  
Author(s):  
Hamed Souriyan-Reyhani pour ◽  
Ramin Khajavi ◽  
Mohammad Esmaeil Yazdanshenas ◽  
Payam Zahedi ◽  
Mohammad Mirjalili
Keyword(s):  
Drug Release ◽  
Cellulose Acetate ◽  
Vinyl Alcohol ◽  
Aqueous Media ◽  
Tetracycline Hydrochloride ◽  
Diameter Distribution ◽  
Poly Vinyl Alcohol ◽  
Release Kinetic ◽  
Phenytoin Sodium ◽  
20 Nm

The objective of this study was to introduce an electrospun hybrid fibrous mat (a dual-fiber drug delivery system) based on cellulose acetate and poly(vinyl alcohol) containing tetracycline hydrochloride and phenytoin sodium, respectively. Characterization of samples was carried by morphology, drug release, cell cytotoxicity, adhesion, antibacterial property, and wettability investigations. The results showed a uniform shape and a narrow diameter distribution of fibers (between 160 ± 20 nm) for fabricated cellulose acetate/poly(vinyl alcohol) hybrid fibrous mat. The tetracycline hydrochloride release from cellulose acetate significantly decreased due to gel formation of poly(vinyl alcohol) in aqueous media. The best fit for drug release kinetic of hybrid sample was Higuchi model. Sample with tetracycline hydrochloride and phenytoin sodium drugs showed improved cell growth, viability, and antibacterial activity against Escherichia coli (~89%) and Staphylococcus aureus (~98%) in comparison with sample without drugs. The hydrophilic property of cellulose acetate/poly(vinyl alcohol) fibrous sample containing the drugs was also remarkable (~45°). To consider the obtained results, the presented hybrid fibrous mat shows a high potent for biomedical applications.

Microscratci I Test on Carbon Films as Thin as 20 nm

1990 ◽  
Vol 188 ◽  
Author(s):  
T. W. Wu ◽  
A. L. shull ◽  
J. Lin
Keyword(s):  
Acoustic Emission ◽  
Large Scale ◽  
Normal Load ◽  
Tangential Force ◽  
Carbon Films ◽  
Small Scale ◽  
Scale Spallation ◽  
First Occurrence ◽  
20 Nm ◽  
Scratch Tests

ABSTRACTThe capabilities to monitor tangential force and acoustic emission have been added to the microscratch mode of the IBM microindenter. These two new monitoring devices combined with the existing normal loadcell enhance the ability of the microscratch test to measure mechanical properties of thin film materials. As a demonstration of the upgraded microindenter, scratch tests were performed on 11 0nm and 20nm thick carbon films deposited on Si <100> substrates. The scratch morphology was examined by scanning electron microscopy to correlate the mechanical data to corresponding failure mechanisms.In the case of the 110nm film, a brittle type fracture was taking place as the applied normal load exceeded a critical value. All three monitored outputs detected the first occurrence of the spallation ofthe film. In contrast to the thicker film, large scale spallation was not observed for thle 20nm film, and the acoustic emission detector did not show any significant output. An apparent friction coefficient(FR) is defined as the ratio ofthe tangential force to the normal load. FR is determined to be a useful parameter for monitoring the indenter's transition through the coating into the substrate, particularly in the case of small scale fracturing or simple ploughing through types of failure.

scholarly journals IMPROVEMENT OF POLYMER SURFACE LAYER BY ELECTRON RADIATION

2020 ◽  
Vol 2020 (2) ◽  
pp. 3882-3886
Author(s):  
Martin Ovsik ◽  
Michal Stanek ◽  
Adam Dockal ◽  
Petr Fluxa
Keyword(s):  
Surface Layer ◽  
Polymer Surface ◽  
Electron Radiation ◽  
Polymer Surface Layer

scholarly journals Blockcopolymer Self-Assembly Directed by Photochemically Attached Polymer Surface Layer

2011 ◽  
Vol 24 (5) ◽  
pp. 581-585 ◽  
Author(s):  
Shigeki Hattori ◽  
Koji Asakawa ◽  
Satoshi Mikoshiba ◽  
Hiroko Nakamura ◽  
Atsushi Hieno ◽  
...  
Keyword(s):  
Surface Layer ◽  
Self Assembly ◽  
Polymer Surface ◽  
Polymer Surface Layer

Well-Ordered Nanoporous Copper Fabricated by Dealloying Cu-Mn and its Characterizations

2016 ◽  
Vol 693 ◽  
pp. 662-668 ◽  
Author(s):  
Biao Tang ◽  
Min Zhou ◽  
Rui Zhou ◽  
Peng Fei Bai ◽  
Guo Fu Zhou
Keyword(s):  
Surface Roughness ◽  
Chemical Composition ◽  
Specific Surface ◽  
Surface Area ◽  
Applied Voltage ◽  
Single Phase ◽  
Porous Structures ◽  
Nanoporous Copper ◽  
Electrochemical Mechanism ◽  
20 Nm

A nanoporous copper (NPC) sample with well-ordered porosity of 20 nm was fabricated by an electrochemical dealloying single-phase Cu0.4Mn0.6 with an external potential of-0.5 V (MSE). The electrochemical mechanism of the dealloying process on the Cu-Mn surface was studied by a liner sweep voltammetry experiment, and an optimized applied voltage for the Cu-Mn system was recommended. The properties of the monolithic NPC, including morphology, chemical composition, surface area and wettability were systematically characterized. The specific surface area around 11.86 m2/g of the as-dealloyed NPC was measured by BET-nitrogen method. The micro/nanoscale bi-continuous 3D porous structures of NPC not only increase the surface area, but also improve the wettability of NPC surface since the increase in surface roughness.

scholarly journals Dataset on a Small-Scale Film-Coating Process Developed for Self-Expanding 4D Printed Drug Delivery Devices

Coatings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1252
Author(s):  
Marco Uboldi ◽  
Alice Melocchi ◽  
Saliha Moutaharrik ◽  
Matteo Cerea ◽  
Andrea Gazzaniga ◽  
...  
Keyword(s):  
Shape Memory ◽  
Smart Materials ◽  
Fused Deposition Modeling ◽  
Surface Characteristics ◽  
Film Coating ◽  
Poly Vinyl Alcohol ◽  
Small Scale ◽  
Prolonged Release ◽  
Coating Process ◽  
Fused Deposition

Film-coating is widely applied in pharmaceutics to enhance aspect/taste and mechanical properties of dosage forms, to protect them from the environment and to modify their release performance. In this respect, a film-coating process was recently involved in the development of 4D printed prolonged-release systems intended for organ retention. During coating processes, liquid formulations are sprayed onto moving cores, whose shape, weight and surface characteristics are essential to attain a homogeneous film. Devices of complex shapes, composed of smart materials and fabricated by hot-processing techniques, such as extrusion and fused deposition modeling 3D printing, might be poorly compatible with the requirements of traditional coating methods, e.g., need for spherical substrates with smooth surface and stable under process temperatures. This work was aimed at evaluating, at a small scale level, the feasibility of a versatile equipment for film-coating of rod-shaped extruded and printed prototypes with different section. Equipment design and set up of process parameters were performed starting from polymeric solutions and suspensions and selecting as cores 50 mm-long rod-shaped samples based on shape memory poly(vinyl alcohol). Integrity and thickness of the applied layer and its impact on shape memory and release performance of prototypes were investigated.

Fluorescence microscopy and spectroscopy of subsurface layer dynamics of polymers with nanometer resolution in the axial direction

2015 ◽  
Vol 184 ◽  
pp. 237-249 ◽  
Author(s):  
Yuri G. Vainer ◽  
Yaroslav I. Sobolev ◽  
Andrei V. Naumov ◽  
Igor S. Osad'ko ◽  
Lothar Kador
Keyword(s):  
Vapor Deposition ◽  
Amorphous Polymer ◽  
Subsurface Layer ◽  
Polymer Surface ◽  
Axial Direction ◽  
Controlled Diffusion ◽  
Subsurface Layers ◽  
20 Nm ◽  
Physical Reasons ◽  
Fluorescent Molecules

We studied the dynamics in ultrathin subsurface layers of an amorphous polymer by the spectra of single fluorescent molecules embedded into the layer by vapor deposition and subsequent controlled diffusion to the desired depth in ≈0.5 nm steps. The spectral trails of single molecules were recorded at 4.5 K as a function of diffusion depth. In depths shallower than 20 nm, the spectral dynamics deviate from those deep in the bulk. Less than 5 nm deep, the linewidths increase rapidly, whereas the number of detected molecules decreases. No zero-phonon lines were observed closer than 0.5 nm to the polymer surface. Possible physical reasons of the observed phenomena are discussed.

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