Tape Test Research Articles

Preparation and characterization of silk fibroin/silica thermal insulation coatings on catheters

Clinical practice of therapeutic hypothermia for neuroprotection in acute cerebral ischemia has been hindered by the warming effect on the cold infusate along the pathway, which results from the poor thermal resistance of the traditional interventional catheter. In this study, thermal insulation coatings with different spray parameters and coating suspension compositions were prepared by air-spraying on a nylon substrate for biomedical application. The surface morphology and microstructure of coatings were investigated by scanning electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy. Silk fibroin (SF) and hollow silica-based nanospheres (HSBNSs) were successfully sprayed on the nylon substrate. The thermal conductivity of the coating measured by a light flash apparatus was down to 0.00105 W/(m K). The tape test indicated that the coatings containing SF, HSBNSs and glyceryl had good adhesion, showing that air-spraying is a promising method to enhance the thermal insulation performance of traditional catheters for cerebral hypothermia therapy.

High Interfacial Thermal Stability of Flexible Flake-Structured Aluminum Thin-Film Electrodes for Bi2Te3-Based Thermoelectric Devices.

Environmental thermal energy harvesting based on thermoelectric devices is greatly significant to the advancement of next-generation self-powered wearable electronic devices. However, the rigid electrodes and interface diffusion of electrodes/thermoelectric materials would lead to the wearable discomfort and performance degradation of the thermoelectric device. Here, a flake-structured Al thin-film electrode with high conductivity and excellent reliability is prepared by regulating the microstructure and crystallinity of the films. The as-prepared Al thin film not only maintains its robustness after 1000 bending cycles but also does not delaminate from the substrate when subjected to the 3M tape test, exhibiting excellent flexibility and adhesion to substrate. By comparing with the annealed interface of the double-layer Cu/Bi2Te3 film, the interface of the heat-treated Al/Bi2Te3 film has almost no element diffusion, demonstrating high interfacial thermal stability. Moreover, a thermoelectric temperature sensor based on the Al thin-film electrode is prepared. The sensitivity of the annealed sensor is still linear, and it can stably monitor the temperature variation, showing high reliability. This discovery could provide a facile and effective strategy to achieving highly reliable thermoelectric devices and flexible electronic devices without any additional diffusion barriers.

Flexible Metal Electrodes by Femtosecond Laser-Activated Deposition for Human-Machine Interfaces.

Flexible metal electrodes are essential for flexible electronics, where the main challenge is to obtain mask-free patterned metals directly on substrates such as poly(dimethylsiloxane) (PDMS) at low cost. This work highlights a feasible strategy named femtosecond laser-activated metal deposition for electroless deposition of metals (Cu, Ni, Ag, and Au) on PDMS, which is suitable for maskless and low-cost fabrication of metal layers on PDMS and even on other materials of different natures including polyethylene terephthalate, paper, Si, and glass. The electrical conductivity of the PDMS/Cu electrode is comparable to that of bulk Cu. Moreover, robust bonding at the PDMS/Cu interface is evidenced by a scotch tape test and bending test of more than 20,000 cycles. Compared with previous studies using a nanosecond laser, the restriction on absorbing sensitizers could be alleviated, and catalysts could originate from precursors without polymer substrates under a femtosecond laser, which may be attributed to nonlinear absorption and ultrashort heating time with the femtosecond laser. Implementing a human-machine interface task is demonstrated by recognizing hand gestures via a multichannel electrode array with high fidelity to control a robot hand.

Modified 3D-printed architectures: Effects of coating by alumina on acrylonitrile butadiene styrene

3D-printed acrylonitrile butadiene styrene (ABS) polymer structures were coated with alumina (Al2O3) using the trimethylaluminum(III) and water atomic layer deposition (ALD) process at 80 °C, which resulted in a 203 nm thin film with a 1.35 Å growth per cycle. This thin film was a well-adhered protective overcoating on ABS to prevent reaction with acetone vapors in a solvent resistance experiment. Scratch tests were not able to remove the overcoating from the polymer surface, which provided a 50% and 32% increase in acetone vapor resistance before initial deformation and complete structure collapse, respectively. A more aggressive tape test caused delamination of the protective coating. This proof-of-concept experiment demonstrates how 3D printing combined with ALD overcoating can alter the chemical characteristics of complex polymer architectures.

Flexible, Elastic, and Superhydrophobic/Superoleophilic Adhesive for Reusable and Durable Water/Oil Separation Coating.

This study investigates a highly flexible/stretchable and mechanically durable superhydrophobic/superoleophilic coating for efficient oil/water separation and oil absorption. The coating is applied via a simple immersion process using a mixed solution of a biocompatible adhesive (ethyl cyanoacrylate, ECA), a highly stretchable polymer (polycaprolactone, PCL), and superhydrophobic/superoleophilic nanoparticles (fluorine-coated silica nanoparticles, F-SiO2 NPs) in a solvent, followed by solvent evaporation and ECA polymerization. Polymerized ECA (poly-ECA) in the coating material strongly adheres the F-SiO2 NPs to the substrate surface, while PCL bestows the rigid poly-ECA with high flexibility. A coated polyurethane sponge exhibits superhydrophobicity (water contact angle of >150°), while retaining robust mechanical stability and flexibility/elasticity. This provides an efficient means of cleaning oil spills with high selectivity, even after mechanical abrasion (>99% separation efficiency is retained after 120 tape test cycles and 50 rubbing test cycles), with excellent reusability.

Enhanced conductivity and stability of Cu-embedded zinc tin oxide flexible transparent conductive thin films

Great challenges remain concerning the cost-effective manufacture of high performance flexible transparent conductive thin films (TCFs). Here, we report flexible TCFs using Cu-embedded zinc tin oxide (ZTO) multilayer structures that are prepared on polyethylene terephthalate (PET) substrates at room temperature. The effects of Cu embedded layer thickness on conductivity and transparency are studied, and a new conduction mechanism is proposed to describe the conduction before and after the critical thickness. At the optimal condition, the films exhibit excellent performance in terms of optical and electrical characteristics, a largest figure of merit value is obtained as 173.2, while the sheet resistance is 9.92 Ω/sq. at an adequate transmittance of 81.2%. The resistance does not show great change after 1000 bending cycles, indicating good flexibility. Meanwhile, the resistance remains nearly constant after 100 tape tests, suggesting a good adhesion to the PET substrate. Moreover, the multilayer thin film exhibits good stability to resist humid and/or hot environments. The improvement of adhesion and stability of multilayer films can be attributed to the effective covering of ZTO on the Cu and disordered molecule arrangement of ZTO layers. In addition, the successful implementation of the multilayer films into a flexible transparent film heater is demonstrated, verifying the applicability.

Fabrication of high-quality flexible transparent conductive thin films with a Nb2O5/AgNWs/Nb2O5 sandwich structure

Different sandwich structures of flexible transparent conductive thin film (TCFs) composed of Nb2O5 layers and Ag nanowires (AgNWs) have been prepared onto flexible polyethylene terephthalate (PET) substrate at room temperature to develop an indium-free TCF. The AgNWs are synthesized by a modified polyol method and inserted into the Nb2O5 layers that are prepared by radio frequency magnetron sputtering. The optical and electrical properties can be modified by changing the number of spin-coating cycle of AgNW suspension. At optimized condition, we achieve a flexible Nb2O5/AgNWs/Nb2O5 sandwich thin film with a low sheet resistance of 9.61 Ω/square and a high optical transmittance of 84.3%. Meanwhile, the resistance remains nearly constant after 30 tape tests, suggesting a strong adhesion to the PET substrate. The sandwich thin films show high long-term stability to oxidation, humid heat, and chemicals compared with that of AgNW networks, which can be attributed to the effective covering of Nb2O5 layer on the AgNWs. In addition, the Nb2O5/AgNWs/Nb2O5 sandwich thin films show good stability after repeated bending. This Nb2O5/AgNWs/Nb2O5 sandwich thin film can therefore serve as a high-performance transparent conductive electrode for numerous flexible electronic devices.

Preparation and antibacterial activity of Ag/TiO2-functionalized ceramic tiles

An Ag/TiO2 coating was deposited onto glazed ceramic tiles by a sol-gel and spraying method at high temperatures. The coating was characterized by X-ray diffraction, scanning electron microscopy, and atomic force microscopy. The results showed that silver was present in rutile-TiO2, and the temperature did not change the phase composition of the samples. The Ag/TiO2 coating had a higher roughness than the TiO2 coating. The tape test (D 3359–08) showed that the coatings prepared at 950 °C and 1000 °C had good adhesion to the ceramic tile substrate. The antibacterial activity of the coating was tested by photocatalytic sterilization experiments. The results showed that the Ag/TiO2 coating had a higher antibacterial activity than the TiO2 coating, and the sterilization efficiency of Escherichia coli, Staphylococcus aureus, Shigella, and Salmonella exceeded 99.655% under 2 h of visible light irradiation. This research provides a method to create Ag/TiO2 coatings with good thermal resistance, adhesion, and antibacterial activity. This improves the low photocatalytic activity caused by the anatase-to-rutile transformation of TiO2 at high temperatures and the poor adhesion at low temperatures.

Bio-based polyurethane coating synthesized from modified castor oil - applicable in base coat of automobile paint

The current study reports the epoxidation of castor oil (CO) by using hydrogen peroxide as catalyst and formic acid as oxidizing agent. Subsequently bio based polyurethane based base coat was synthesized by using epoxidised castor oil (ECO) as polyol, Isophorone diisocyanate (IPDI) as curing agent and dibutylin dilaurate (DBTDL) as catalyst. The paint formulation with OH:NCO ratio 1:1.2 was optimized. An independent study was carried out employing the mechanical test like cross-cut tape test was carried out to evaluate th paint properties. Morphological and structural studies like FTIR, SEM, HNMR were carried out with the paint formulation. Thermal property studies like TGA, DSC were carried out with the paint. Gloss, weather resistance of the paint was evaluated.

Flexible transparent conductive ZnSnO/Cu/ZnSnO multilayer films for flexible transparent heaters

The characteristics of low-cost ZnSnO/Cu/ZnSnO multilayer films as potential flexible transparent electrodes and heaters are investigated. The multilayer films show a low sheet resistance of 9.92 Ω/sq. at optical transmittance of 81.2%. Calculation of figure of merit shows a large value of 173.2, which is superior to that obtained from the flexible ITO and other Cu based hybrid films. The resistance remains nearly constant after 1000 bending cycles and 100 tape tests, indicating good flexibility and adhesivity. Furthermore, the multilayers also exhibit excellent stability under hot and humid environment. Finally, the successful implementation of the multilayer films into a flexible transparent film heater is demonstrated, verifying the applicability.

Synthesis and characterization of thermally-evaporated CdS thin-films

Cadmium sulfide (CdS) thin films (thickness: 200 nm) were grown over silicon (Si) substrate via thermal evaporation deposition method, where the ultimate pressure and deposition rate were 1 × 10−6 torr and 1.0-1.2 Å/sec, respectively. X-ray diffraction established polycrystalline films with a hexagonal crystal structure and preferred orientation (002). The energy dispersive analysis of X-ray has recognized pure and stoichiometric films. The uniform, dense and smooth films with low roughness (1.4 nm) appeared in atomic force microscopy. The scanning electron microscopy characterization has recognized a continuous and defects-free film (like cracks, pinholes and overhang) with a uniform distribution of interconnected nanoparticles (size: 24.5–35.1 nm). The good adhesion of the film was confirmed via a scotch tape test. Ellipsometry revealed that the grown CdS film has a refractive index of 2.42–2.45. Thus, polycrystalline CdS film with hexagonal phase (highly stable, wide bandgap, high transmission, environmentally tolerable, and good mechanical strength) could be utilized as a suitable window material and passivation agent in the fabrication of solar cell and infrared detector, respectively.

Enhancing ink adhesion of specialty paper using an interpenetrating polyvinyl alcohol-blocked polyurethane polymer network sizing system.

The printing quality and strength of specialty papers such as money, maps, newspapers and bank notes have been a significance challenge in recent years. The adhesive effect between ink and paper is depend on both the secondary binding force between the molecules and the mechanical anchoring effect of the ink on the paper. Also, the porous and fibrous structures of base paper restrain its application in printed products because of the strong capillary effect leading to the diffusion of ink particles. To address the problems involved in ink diffusion and mechanical reinforcement, surface sizing is an attractive choice from the perspective of paper handling. Herein, the surface sizing system of specialty paper with an interpenetrating polyvinyl alcohol-blocked polyurethane polymer network was applied to fabricate paper of high ink adhesive properties. In the case of the same external factors (gluing temperature, drying time, etc.), the surface sizing effect of paper samples (sizing with TBPU, polyvinyl alcohol and TBPU/PVA system) were evaluated by infrared spectroscopy, X-ray photoelectron spectroscopy, water contact angle measurements and scanning electron microscopy. Some of the pure cotton pulp paper with surface sizing treatment was treated via adhering inks to paper by spraying, smearing and soaking. The bonding strength was tested by peel-off tape tests, soaking tests, and simulated washing tests. The results showed that the water contact angle of the sized-paper increased from 67.6° to 89.7°. The mechanical properties had been greatly improved after treatment and SEM, AFM and XPS analyses indicated an increase in surface roughness and the oxygen-containing polar groups (C Created by potrace 1.16, written by Peter Selinger 2001-2019 ]]> O, C–OH, –NH–COO– and COOH) enhanced the fixation of ink particles on the fiber surface. These tests indicated that the novel composite system of TBPU/PVA could endow specialty paper with superb mechanical properties and more than 90% ink retention rate. All these advantages of this composite system may contribute to its wide application in the fields of papermaking and printing.

Degradable, ultra-flexible, transparent and conductive film made of assembling CuNWs on chitosan

The rapid development of wearable and disposable electronic devices and the rising awareness of environmental sustainability impose growing new demands on the nature degradability of current electronic systems. It is a challenge to fabricate degradable, ultra-flexible, transparent and conductive films (TCFs), which are essential component of wearable devices. Here, a new type of degradable, ultra-flexible TCFs made from green and earth abundant materials are reported. The TCFs are achieved by embedding copper nanowires (CuNWs) into chitosan strategy via simple sol-gel transition. The prepared TCFs exhibit favorable optical and electrical properties (83.7% at the sheet resistance of 14.1 Ω/sq.). Calculation of figure of merit displays a high value of 143.7, which is superior to that obtained from the flexible ITO, carbon nanotubes, graphene, and other CuNWs based TCFs. In particular, excellent insensitivity conductivity are achieved with a bending radius of 0.1 mm and the sheet resistance remains nearly to be constant after 1000 bending cycles with a bending radius of 1.0 mm. Moreover, the TCFs show good stability to resist tape test and ultrasonication, and which can be completely dissolved in city running water contains 2% acetic acid after ten days under the natural condition, demonstrating an excellent nature degradability. Finally, the successful implementations of the degradable flexible transparent heater and electroluminescent device demonstrate the practical application value of the TCFs.

Optimizing And Comparative of Polymer-45S5BG and Polymer- HA Coating by Electrophoretic Deposition (EPD)

In this study, two systems of bio-ceramic coating (45S5 bioactive glass and hydroxyapatite) were used in order to compare between them for biomedical applications. Each system consists from two layers of coating done by electrophoretic deposition (EPD) technique on 316L stainless steel material as substrate. Two types of biopolymer were used (Chitosan with Gelatin) as first layer of coating. Taguchi approach with L9 array was used in order to choose the best conditions (concentrations, voltage and time) for coating layers. Each system consists of two layer (biopolymer (first layer) and bioceramic (second layer)) materials. The optimum parameters for first layer of biopolymer was (3g/L concentration, 20 voltage and 3 minute) while optimum parameter for second layer (6g/L concentration, 30 voltage and 1 minute) for two bioceramic group. Zeta potential test were employed to measure suspensions stability. The tape test method was used to evaluate the adhesion between substrate and coating layers, the results show that the percentage of removal area for optimum coating layer (biopolymer, 45S5 BG and HA 8.06%, 10.668%, 6.23% subsequently). XRD inspection was used for identify the phases of coating layers. The Cyclic polarization test was used for evaluation of pitting corrosion resistance, the results show all layers gives good corrosion resistance but 45S5BG gives the best corrosion resistance when compared with HA system.

Heat treatment for bactericidal particulate silver plating on 316L stainless steel

AbstractThe paper presents the impact of heat treatment on the characteristics of the particulate silver plating on 316L stainless steel. Heat treatment was applied in Argon gas media at 500, 600, and 800 oC for 15 minutes. Advanced evaluation methods was applied as scanning electron microscopy (SEM) for surface morphology assessment, tape tests for adhesion determination of silver plating, atomic absorption spectroscopy (AAS) for released concentration of ions in the simulated body fluid (SBF). The antibacterial effect of the silver plating versus Escherichia coli was evaluated through inhibition of bacterial growth after 60 minutes of exposure. The SEM images indicated that there is no change on the grain boundaries after heat treatment. The adhesion of the silver plating increased while increasing temperature from 500 to 800 oC; and the released concentration of silver ion in SBF decreased. The antibacterial effect efficiency of silver plating was from 92 to 99 %. The released concentration of silver ion in SBF after 168 hours was in range of 0.012÷0.18337 μg/mL with average silver plating content was 6.0 mg, much lower in comparison with the allowed threshold of released concentration of silver ion in human body fluid (10 μg/mL).

Sustainable flame retardant coating based graphene oxide and montmorillonite

A comparative study of epoxy filled graphene oxide (GO) and montmorillonite (MMT) and its combination on the flame retardancy and thermal stability of epoxy nanocomposite coatings has been investigated. Limiting oxygen index (LOI) and thermogravimetry analysis (TGA) were carried out to determine the flame retardancy and thermal stability properties and clarifying the correlations between different nanofillers fraction. The result suggests that the formation of an efficient hybrid network evidenced by enhanced the flame retardancy as well as thermal stability performance of epoxy nanocomposite coating. The adhesion tape test results revealed that hybrid nanofillers exerts an obviously synergistic effect, demonstrated by the increased in adhesion strength compare to a single nanofillers. Transmission electron microscopy (TEM) revealed a high dispersion of hybrid GO/MMT due to the physical interaction between the nanofillers and epoxy matrix, responsible for the improved of coating’s performance.

First study on oxyuriosis in horses from Algeria: Prevalence and clinical aspects

The present study was carried out the Tiaret region, on horses belonging to the Chaouchaoua National Haras, ONDEEC and on two private farms during the period from February 05th to April 17th, 2019. It aims to assess the overall prevalence of equine oxyuriosis in the area and to describe the most dominant clinical signs of this parasite infection. Scotch tape test was applied on 176 horses randomly selected and the microscopic observation of slides was carried out at the parasitology laboratory of the Veterinary institute of Tiaret. The overall prevalence of Oxyuris equi was 38.64% with females being more infected (37.04%) than males (20.45%). The prevalence of oxyuriosis was higher in fillies (70%) than in foals (48.39%).The high prevalence of Oxyuris equi was recorded in the private farms with a percentage of 85% and 44% in farm 1 and 2, respectively. The more commonly clinical signs were tail rubbing in 42% and scratching in 32% of positive horses.Equine oxyuriosis is a common infection in the study area and requires the application of hygienic measures with more therapeutic and preventive care.

Sequential manufacturing via intra-additive hybrid materials approach for fully roll-to-roll processed flexible organic thin film transistors

Conventional conductive films that are used as electrodes in organic thin film transistors (OTFTs) are susceptible to mechanical deformation, limiting the applicability of such films in flexible wearable electronic devices. To address this limitation, a hybrid conductive film (HCF) consisting of silver nanowires (NWs) and poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonate) (PEDOT:PSS) fabricated through roll-to-roll (R2R) slot-die coating is presented for use as a gate electrode in OTFTs. Mechanical stability compares by bending and taping test measurement quantitatively. Coating flow rate significantly influences sheet resistance and transmittance. A performance evaluation of the OTFTs with the Ag NW/PEDOT:PSS HCF as the gate electrode shows that the charge carrier mobility and on/off current ratio are 2.168 cm2 V−1 s−1 and 6 × 105, respectively. In addition, the HCF is highly flexible, and the HCF-based OTFTs exhibit 57% less mobility reduction than a conventional OTFT based on silver ink after 50,000 bending cycles with a 2 mm bending radius. These results highlight the potential of the fabricated HCF as an electrode material for flexible electronic devices.

Cellulose nanocrystal reinforced silk fibroin coating for enhanced corrosion protection and biocompatibility of Mg-based alloys for orthopedic implant applications

In this work, a novel coating material based on silk fibroin (SF) and cellulose nanocrystals (CNCs) was developed on biodegradable AZ31 Mg alloy and assessed for corrosion resistance and biocompatibility. Before the application of the coating, AZ31 substrate was modified with a layer of polydopamine to enhance the adhesion of the protective coating to the metal surface as confirmed by the adhesion tape test. SEM images revealed the formation of a defect-free and uniform SF-CNC coating with a thickness of 11.2 ± 2.5 μm on AZ31 alloy. The results of the electrochemical corrosion and in vitro immersion tests clearly demonstrated an enhanced corrosion resistance of the SF coating after the incorporation of CNCs. Compared to the unmodified Mg alloy, the SF-CNC coated AZ31 exhibited a remarkably improved cytocompatibility with a viability of 114% and excellent adhesion and spreading of human fetal osteoblast cells onto the coating surface. The findings of this work highlight the great potential of SF and CNC as bio-based nature-derived anticorrosive nanofillers for fabrication of protective and biocompatible coatings on Mg-based biodegradable orthopedic implants.

3D printed solder masks for printed circuit boards

The use of additive technologies in the creation of soldering masks opens up new opportunities in the production of printed circuit boards, in particular, the use of soldering masks for boards with integrated components. The paper considers the results of experimental data on the adhesion of 3D soldering masks (that is, masks created on a 3D printer) obtained during the study of the introduction of 3D printing into electronic manufacturing processes. For the analysis of adhesion, it is possible to use such methods as breaking load, cross-cut test, and the sticky tape method. A number of experiments were conducted to study the adhesion by testing the breaking load. The samples were formed with different ratios of prepreg/solder mask, then the force at which the fracture occurred was measured. The essence of the cross-cut test is to apply at least three parallel cuts and perpendicular to them also at least three parallel cuts with the tip of the cutter. After the scratching, there must be no flaking of the coating between the lines and in the grid of squares, then the results are assessed. Sticky tape tests are performed by applying the tape with the adhesive side to the test sample with a cured coating applied. The results are assessed by visual inspection using an optical device that provides 3x magnification. The results of the breaking load experiments indicate that 3D masks show comparable separation forces with a prepreg. At the same time, the force is stable for all types of surfaces and practically does not depend on the thickness and configuration of the 3D mask. Experiments with applying cross-cuts show consistently good results with a homogeneous base material – there are no coating detachments. The paper concludes that the use of 3D soldering masks on the inner layers of multilayer printed circuit boards with built-in components is possible, but a number of issues must be solved for this, including those related to the software for forming 3D structures of masks.