scholarly journals Functional Tapered Fiber Devices Using Polymeric Coatings

2021 ◽  
Author(s):  
Oscar González-Cortez ◽  
Rodolfo A. Carrillo-Betancourt ◽  
Juan Hernández-Cordero ◽  
Amado M. Velázquez-Benítez
Keyword(s):  
Optical Properties ◽  
Optical Fibers ◽  
Polymer Coating ◽  
Light Propagation ◽  
Functional Polymers ◽  
Polymer Coatings ◽  
Polymeric Coatings ◽  
Liquid Polymer ◽  
Fiber Devices ◽  
Special Case

A wide variety of fiber devices can be created by adding special coatings on tapered sections of optical fibers. In this work we present the fundamentals for the fabrication of tapered optical fibers coated with functional polymers. The required aspects of light propagation in tapered sections of optical fibers are introduced and the relevant parameters enabling light interaction with external media are discussed. A special case of interest is the addition of polymeric coatings with prescribed thicknesses in the tapered sections allowing for adjusting the light propagation features. We assess the use of liquid polymer coatings with varying thicknesses along the taper profile that can be tailored for tuning the transmission features of the devices. Hence, we introduce a methodology for obtaining coatings with predefined geometries whose optical properties will depend on the polymer functionality. As demonstrated with numerical simulations, the use of functional polymer coatings in tapered optical fibers allows for obtaining a wide variety of functionalities. Thus, controlled polymer coating deposition may provide a simple means to fabricate fiber devices with adjustable transmission characteristics.

Porous Polymer Coatings Based on Nitrocellulose

2019 ◽  
Vol 968 ◽  
pp. 68-75
Author(s):  
Valeriy Vyrovoy ◽  
Viacheslav Bachynckyi ◽  
Nadia Antoniuk
Keyword(s):  
Porous Structure ◽  
Cellular Structure ◽  
Polymer Coating ◽  
Experimental Studies ◽  
Polymer Coatings ◽  
Porous Polymer ◽  
Polymeric Coatings ◽  
New Approach ◽  
Porous Coatings

The paper presents the development of optimum structures and the production of polymeric coatings technology which can absorb aggressive substances. The studies of coatings penetrating into the film are presented due to the organization of their capillary-cellular structure by introducing special fillers. A new approach to solve the problem of protecting the environment, people, buildings and structures from the effects of aggressive substances has been proposed. The essence of the method consists in the preventive deposition on the surfaces of construction objects of porous coatings that can irreversibly absorb aggressive substances. Based on theoretical and experimental studies, porous coatings have been developed that are capable of accumulating in their volume aggressive substances, as well as certain principles of providing the coating with the necessary capillary-porous structure. The mechanism of creating a capillary-cellular structure of a polymer coating based on nitrocellulose are substantiated.

scholarly journals Thiophene-Based Trimers and Their Bioapplications: An Overview

Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1977
Author(s):  
Lorenzo Vallan ◽  
Emin Istif ◽  
I. Jénnifer Gómez ◽  
Nuria Alegret ◽  
Daniele Mantione
Keyword(s):  
Optical Properties ◽  
Medical Research ◽  
Turning Point ◽  
State Of The Art ◽  
Thiophene Ring ◽  
Functional Polymers ◽  
Direct Application ◽  
Synthetic Methods ◽  
Scientific Interest ◽  
Chemical Modifications

Certainly, the success of polythiophenes is due in the first place to their outstanding electronic properties and superior processability. Nevertheless, there are additional reasons that contribute to arouse the scientific interest around these materials. Among these, the large variety of chemical modifications that is possible to perform on the thiophene ring is a precious aspect. In particular, a turning point was marked by the diffusion of synthetic strategies for the preparation of terthiophenes: the vast richness of approaches today available for the easy customization of these structures allows the finetuning of their chemical, physical, and optical properties. Therefore, terthiophene derivatives have become an extremely versatile class of compounds both for direct application or for the preparation of electronic functional polymers. Moreover, their biocompatibility and ease of functionalization make them appealing for biology and medical research, as it testifies to the blossoming of studies in these fields in which they are involved. It is thus with the willingness to guide the reader through all the possibilities offered by these structures that this review elucidates the synthetic methods and describes the full chemical variety of terthiophenes and their derivatives. In the final part, an in-depth presentation of their numerous bioapplications intends to provide a complete picture of the state of the art.

scholarly journals Physical Properties of Electropolished CoCrMo Alloy Coated with Biodegradable Polymeric Coatings Releasing Heparin after Prolonged Exposure to Artificial Urine

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2551
Author(s):  
Wojciech Kajzer ◽  
Janusz Szewczenko ◽  
Anita Kajzer ◽  
Marcin Basiaga ◽  
Joanna Jaworska ◽  
...  
Keyword(s):  
Physical Properties ◽  
Crevice Corrosion ◽  
Mass Density ◽  
Polymer Coatings ◽  
Metal Substrate ◽  
Reference Level ◽  
Polymeric Coatings ◽  
Initial State ◽  
Cocrmo Alloy ◽  
Artificial Urine

In this study, we aimed to determine the effect of long-term exposure to artificial urine on the physical properties of CoCrMo alloy with biodegradable heparin-releasing polymeric coatings. Variants of polymer coatings of poly(L,L-lactide-ɛ-caprolactone) (P(L,L-L/CL)) and poly(D,L-lactide-ɛ-caprolactone) (P(D,L-L/CL)) constituting the base for heparin-releasing (HEP) polyvinyl alcohol (PVA) coatings were analyzed. The coatings were applied by the dip-coating method. Heparin was used to counteract the incrustation process in the artificial urine. The study included tests of wettability, resistance to pitting and crevice corrosion, determination of the mass density of metal ions penetrating into the artificial urine, and the kinetics of heparin release. In addition, microscopic observations of surface roughness and adhesion to the metal substrate were performed. Electrolytically polished CoCrMo samples (as a reference level) and samples with polymer coatings were used for the tests. The tests were conducted on samples in the initial state and after 30, 60, and 90 days of exposure to artificial urine. The analysis of the test results shows that the polymer coatings contribute by improving the resistance of the metal substrate to pitting and crevice corrosion in the initial state and reducing (as compared with the metal substrate) the mass density of metal ion release into the artificial urine. Moreover, the PVA + HEP coating, regardless of the base polymer coatings used, contributes to a reduction in the incrustation process in the first 30 days of exposure to the artificial urine.

scholarly journals Novel Bloch wave excitation platform based on few-layer photonic crystal deposited on D-shaped optical fiber

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Esteban Gonzalez-Valencia ◽  
Ignacio Del Villar ◽  
Pedro Torres
Keyword(s):  
Optical Fibers ◽  
High Performance ◽  
Light Propagation ◽  
Fiber Optic ◽  
Layer Structure ◽  
Optical Network ◽  
Building Blocks ◽  
Bloch Wave ◽  
Nanophotonic Devices ◽  
Wide Range

AbstractWith the goal of ultimate control over the light propagation, photonic crystals currently represent the primary building blocks for novel nanophotonic devices. Bloch surface waves (BSWs) in periodic dielectric multilayer structures with a surface defect is a well-known phenomenon, which implies new opportunities for controlling the light propagation and has many applications in the physical and biological science. However, most of the reported structures based on BSWs require depositing a large number of alternating layers or exploiting a large refractive index (RI) contrast between the materials constituting the multilayer structure, thereby increasing the complexity and costs of manufacturing. The combination of fiber–optic-based platforms with nanotechnology is opening the opportunity for the development of high-performance photonic devices that enhance the light-matter interaction in a strong way compared to other optical platforms. Here, we report a BSW-supporting platform that uses geometrically modified commercial optical fibers such as D-shaped optical fibers, where a few-layer structure is deposited on its flat surface using metal oxides with a moderate difference in RI. In this novel fiber optic platform, BSWs are excited through the evanescent field of the core-guided fundamental mode, which indicates that the structure proposed here can be used as a sensing probe, along with other intrinsic properties of fiber optic sensors, as lightness, multiplexing capacity and easiness of integration in an optical network. As a demonstration, fiber optic BSW excitation is shown to be suitable for measuring RI variations. The designed structure is easy to manufacture and could be adapted to a wide range of applications in the fields of telecommunications, environment, health, and material characterization.

scholarly journals Analysis: Particulate Limits for Intravascular Devices: Considerations for Polymer Coating Embolism

2019 ◽  
Vol 53 (6) ◽  
pp. 426-432 ◽  
Author(s):  
Amitabh Madhukumar Chopra
Keyword(s):  
Polymer Coating ◽  
Animal Studies ◽  
Polymer Coatings ◽  
Medical Instrumentation ◽  
New Device ◽  
Iatrogenic Complication ◽  
Industry Standard ◽  
Step Procedure ◽  
Release Limits ◽  
Intravascular Devices

Abstract Lubricious polymer coatings are increasingly used on intravascular devices to facilitate easier access and navigation through tortuous blood vessels. Recent reports highlight the separation and downstream embolism of polymer particles affecting the vasculature and various organs. The Food and Drug Administration (FDA) acknowledges polymer coating embolism as an iatrogenic complication of intravascular devices and continues to close gaps in standards related to coating integrity. The Association for the Advancement of Medical Instrumentation established particulate testing as an industry standard for evaluating coating integrity of intravascular devices. The FDA recognizes this standard; however, challenges exist in setting particulate limits that may compromise device function without sufficient clinical data. The microscopic nature of polymer emboli not visible with available imaging modalities has impacted reporting. This has also resulted in a reduced number of manufacturer-driven product development projects related to coating integrity. On the other hand, recent procedural trends have supported the innovation of coated devices with expanded indications, requiring particulate evaluations and release limits. This article proposes a methodology to set particulate limits for intravascular devices given existing clinical, regulatory, and manufacturing challenges. The approach with standardization requirements enables characterization, comparison, and evaluation of lubricious coatings from various manufacturers. It incorporates a step-by-step procedure that adds scrutiny to the application of coatings while ensuring device function is not impacted. Together with particulate assessments, clinicopathologic and animal studies permit an understanding of particulate ranges from commercially available devices and setting of particulate limits for new device evaluations.

Adhesion and Electrical Insulation of Thin Polymeric Coatings Under Saline Exposure

1987 ◽  
Vol 110 ◽  
Author(s):  
R. N. Leyden ◽  
D. I. Basiulis
Keyword(s):  
Barrier Properties ◽  
Peel Strength ◽  
Polymer Coatings ◽  
Polymeric Coatings ◽  
Adhesive Failure ◽  
Short Term ◽  
Leakage Currents ◽  
Electrical Bias ◽  
Implanted Devices

AbstractA study was made of the adhesion of insulating polymer coatings under long term exposure to electrical bias. Since a common mode of failure in implanted devices is the penetration of water into poorly adhering insulation/conductor interfaces followed by electrolytic degradation, development of processes, primers, and insulators with good adhesion that resist the effects of water were sought. Polyimide coatings were tested for their ion barrier properties by immersion of insulated comb patterns in saline with 9 V D.C. bias between the comb fingers. Leakage currents, measured over three years exposure, increased from several picoamps initially to several nanoamps in surviving specimens. Subsequent studies showed that dramatic improvements in the moisture durability of the adhesion could be obtained using Hitachi's aluminum chelate type primer. Whereas the peel strength of polyimide on unprimed platinum fell more than 90% after several hours of boiling saline exposure, the peel strength of polyimide coatings on primed surfaces remained at over 80% of their initial values. ESCA analysis of the peel interfaces showed that both aluminum oxide and polyimide remain on the substrate after peeling back the polyimide. This suggests a combination of cohesive and adhesive failure at the primer/polyimide interface. The effects of exposure of the polymer/substrate interfaces (edges) to saline and electrochemical stress were examined by patterning circular openings in the polyimide. A 10 V anodic potential was found to damage adhesion to titanium as far as 75 microns away from the edge. Pulsing at 500 Hz, 1 V peak to peak was found to have no measurable effect in the short term.

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