PVC Substrate Research Articles

Design and numerical simulation of modified tunable THz filter based on periodic graphene-PVC ribbons

In this article, we propose a tunable terahertz (THz) filter composed of graphene layers and a PVC substrate. A novel approach utilizing a static magnetic field is introduced to tune the resonance frequency. The presence of a magnetic field and gyromagnetic materials like graphene enables the proposed configuration to exhibit both TE and TM polarizations in the output structure. Additionally, a remarkable tunability of about 5 THz bandwidth is achieved, a considerably high value compared to existing works. All results are obtained through numerical simulations using MATLAB software based on the transfer matrix method (TMM), and the accuracy is verified using COMSOL software. With nearly zero transmission, this exceptionally tunable THz filter holds great potential for various applications, including THz spectrometry.

Cost-effective quantification of uric acid using niobium oxide and graphene oxide-modified pencil-drawn electrodes on PVC substrates.

This study introduces a cost-effective approach for quantifying uric acid (UA), the main antioxidant species in human physiology and implicated in inflammatory regulation. Using a PVC substrate and pencil drawing technique, electrodes were fabricated and modified with niobium oxide and graphene oxide via a straightforward "drop casting" method. The nanostructures of the substrate, electrode, and modified electrode were evaluated using SEM images. The synergistic effect between these materials significantly facilitated the uric acid oxidation process with a 400 mV peak potential shift and 45% current increase. The evaluation of the electrode's response to common blood and urine components showed minimal deviation. Among the components tested-ascorbic acid, glucose, nitrate, nitrite, cysteine, urea, creatinine, and ammonium ion-only the ammonium ion exhibited a 10% interference at concentrations commonly found in urine. The sensors showed a good detection limit of 8.7 μmol L-1, with a wide linear range from 8.7 to 2000 μmol L-1 with a correlation factor of 0.9993 for five different sensors. The reproducibility and repeatability of the produced sensors were estimated by the RSD at 4% and 1%, respectively. Synthetic urine samples spiked exhibited reliable analysis, with recovery values within a 5% error margin. This work presents a practical, simple, and affordable sensor platform for rapid and accurate UA quantification.

Surface modification of polyvinyl chloride with sodium alginate/carboxymethyl chitosan and heparin for realizing the anticoagulation

Thrombosis of extracorporeal circuits causes significant morbidity and mortality worldwide. In this study, plasma treatment technology and chemical grafting method were used to construct heparinized surfaces on the PVC substrate, which could not only reduce thrombosis but also decrease the side effects of the direct injection of anticoagulants. The PVC substrate was modified by plasma treatment technology firstly to obtain the active surface with the hydroxyl groups used for grafting. Then, heparin was grafted onto the modified PVC surface using different grafting strategies to prepare different heparinized surfaces. The experimental results indicated that the sodium alginate (SA) and carboxymethyl chitosan (CCS) used as interlayers could significantly increase the graft density of heparin to improve the anticoagulant effects and hemocompatibility of heparinized surfaces. In addition, the modification of heparin can further improve the anticoagulant effects. The CCS/low-molecular-weight heparin (LWMH) surface has the best anticoagulant properties, which can prolong the activated partial thromboplastin time (APTT) values of human plasma for about 35 s, reduce the hemolysis rates to <0.3 %, and perform well in the in-vitro blood circulation test. The heparinized surfaces prepared in this work have great application potential in anticoagulant treatment for medical devices.

Improving surface characteristics and operational parameters of polyvinyl chloride ultrafiltration membranes: How to manipulate the performance of thin film composite forward osmosis membranes?

The environmental and economic costs are pivotal aspects that should be considered before the commercialization of any membrane separation-based process. Particularly, realizing this goal relies entirely on the key role played by fabrication and operational parameters. Herein, we introduced a systematic investigation for constructing thin-film composite (TFC) - forward osmosis (FO) membranes for direct fertigation applications. To the best of our knowledge, PVC membrane was rarely used as a porous top surface substrate for TFC-FO membranes. The PVC substrate porous structure and polyamide (PA) active layer were manipulated by variating their concentrations and reaction time to optimize the FO membrane performance. All necessary characterization tools were employed to visualize the fabricated TFC membrane's surface characteristics. The influence of feed solution concentration, membrane orientation, flow rate, and draw solutes on the FO work was also methodically tested. Results demonstrated that the porous structure-substrate membrane host polymer content had imparted a significant role in tailoring the TFC-FO performance concerning permeability and back-solute flux. The water flux was improved by 44.3 % with decreasing of the PVC amount, whereas water flux was improved by 48.13 % with decreasing of the M-phenylenediamine monomer (MPD) content from 3 to 1 wt% at constant tri-mesoylchloride monomer (TMC) content of 0.1 wt% in IP reaction conditions of a thin film. This was gone hand in hand with optimal operational conditions harnessed for optimizing the FO process.

Shape‐controlled synthesis of polyaniline and its synergistic effect with reduced graphene oxide for the fabrication of flexible electrode

AbstractComposite of reduced graphene oxide (rGO) and polyaniline (PANI) have gained much attention in industrial applications especially for the fabrication of supercapacitor and flexible sensors. Nevertheless, existing studies mainly focus on the application efficiency and are lacking information on how morphology of the nanoparticles can affect the electrode properties. Herein, the effects of shape of PANI on the electrode resistivity were systematically investigated. PANI of different shapes was synthesized using different reagents, namely H2SO4, CH3COOH, H2O, and NH3·H2O, which induced formation of globule, tube, plate, and flake‐like PANI. rGO‐PANI composite was then produced using ex situ method and cast on a PVC substrate to form a flexible electrode. The rGO‐PANI globules displayed superior electrical conductivity owing to its high protonation level. The resistivity of this sample was found to be 0.015 ± 0.002 Ωcm, which is lowest as compared to the counterparts. Interestingly, electrode made of rGO‐PANI plates had a slightly lower electrical resistivity than rGO‐PANI tubes despite its low protonation level. It is speculate that the aspect ratio characteristic of the PANI might have influence the electron mobility. rGO‐PANI electrode was found to exhibit a lower specific resistivity than pure rGO and pure PANI, evincing the presence of synergism.

Microgel reinforced zwitterionic hydrogel coating for blood-contacting biomedical devices

Zwitterionic hydrogels exhibit eminent nonfouling and hemocompatibility. Several key challenges hinder their application as coating materials for blood-contacting biomedical devices, including weak mechanical strength and low adhesion to the substrate. Here, we report a poly(carboxybetaine) microgel reinforced poly(sulfobetaine) (pCBM/pSB) pure zwitterionic hydrogel with excellent mechanical robustness and anti-swelling properties. The pCBM/pSB hydrogel coating was bonded to the PVC substrate via the entanglement network between the pSB and PVC chain. Moreover, the pCBM/pSB hydrogel coating can maintain favorable stability even after 21 d PBS shearing, 0.5 h strong water flushing, 1000 underwater bends, and 100 sandpaper abrasions. Notably, the pCBM/pSB hydrogel coated PVC tubing can not only mitigate the foreign body response but also prevent thrombus formation ex vivo in rats and rabbits blood circulation without anticoagulants. This work provides new insights to guide the design of pure zwitterionic hydrogel coatings for biomedical devices.

Novel Strategy for the Development of Antibacterial TiO2 Thin Film onto Polymer Substrate at Room Temperature.

This work demonstrates a novel method to deposit an antibacterial TiO2 thin film on a polymer substrate at room temperature. A combination of sol–gel and photon assistance was used in the experiment in order to avoid any thermal processes of thin film crystallization. The morphological photograph of samples indicated that the TiO2 thin film was perfectly coated on the PVC substrate without any cracks or pinholes. Chemical analysis by EDS and XPS reported that the thin film consisted of titanium (Ti), oxygen (O), and carbon (C). The Raman spectrum proved that the thin film was the anatase phase of TiO2 and, furthermore, that it was contaminated with carbon remaining from the photon assistance process. In addition, the optical band gap of the thin film was 3.35 eV, suggesting that the photocatalytic activity of TiO2 should occur under UV-A radiation. The bacteria viability assay was examined using E. coli and S. typhimurium as indicator strains under UV-A irradiation (365 nm) at different times. The data from OD and CFU count revealed that >97% of bacteria were killed after 60 min of irradiation, and the bacteria were completely killed at 120 min for E. coli and 180 min for S. typhimurium.

Structural, optical and electrical properties of PVC/Au thin films prepared by sputtering process

Optical, structural and electrical properties of Au thin films (20, 40, 60, 80 and 100 nm) deposited on poly(vinyl chloride) substrates by sputtering process were investigated. The deposition of gold thin layers was carried out under low pressure at room temperature. UV/VIS characterization demonstrated the presence of surface plasmon peak corresponds to Au nano thin film at about 500–550 nm. The intensity of the peak was increased as the layer thickness increased. Structural investigation using FTIR technique illustrated that the deposited gold thin layer onto PVC surface was largely affected by the shape and position of the functional groups of PVC substrate. The electrical properties of PVC/sputtered gold thin films were investigated at room temperature over a wide range of frequency (20 Hz up to 5 × 106 Hz). The dc conductivity increased from 2.63 × 10−14 S/m for pure PVC sample up to 9.54 × 10−13 S/m for 80 nm Au thin layer, while the resistance decreased from 3.17 × 1012 (Ώ) down to 9.54 × 1010 (Ώ) (97% decrement).

ZnO NANORODS GROWN ON PLASTIC PVC SUBSTRATE FOR ENVIRONMENTAL APPLICATION

In this work, the hydrothermal growth of ZnO nanorods (NRs) on plastic PVC substrate is presented. It was shown that ZnO NRs with high density and high crystallinity can be successfully grown by implementing saturated nutrition solution of zinc nitrate hexahydrate (Zn[NO3]2·6H2O) and hexamethylenetetramine (C6H12N4) without the assistance of a seed layer. The morphologies of the ZnO nanorods investigated by scanning electron microscope (SEM) demonstrated hexagonal structures. The crystallinity of the ZnO NRs was studied by photoluminescence (PL) spectroscopy. The as-grown ZnO NRs were then utilized for photocatalytic degradation of methylene blue.

An ultrasimple and cost‐effective µPAD by pasting hydrophilic channels to a hydrophobic basement

AbstractThe application of the paper‐based microfluidic device (µPAD) as a potentially significant platform for clinical diagnoses has gained a great interest during the recent years. This work presented a technically ultrasimple, low‐cost, effective, and rapid method for the µPADs fabrication by pasting a hydrophilic flower‐like paper mask to a hydrophobic PVC substrate, which was purchased with adhesive on it. The whole manufacture process could be implemented in a few seconds by untrained personnel. To demonstrate the feasibility of this method in real‐world situations, the developed paper device was employed for colorimetric assays of glucose in artificial urine and nitrite in artificial saliva. The main analysis parameters, for example, the optimum volumes of reagents, reaction time, and so forth, were seriatim optimized. Under optimal conditions, the detection limits were 0.9 mM and 19.5 µM for glucose and nitrite, respectively; the detection ranges were 0.9–30 mmol/L and 19.5–312.5 µmol/L for glucose and nitrite analyses, respectively. These results showed that this equipment‐free µPAD had great potentials for the qualitative or semiquantitative detection of glucose and nitrite in real samples.

Study of scratch resistance of a hard-on-soft polymer bilayer: Combination of in situ vision, X-ray tomography and numerical simulations

The deposition of a hard coating is a commonly used solution to increase the scratch resistance of soft polymeric materials at low and moderate normal loads. But the major risk for a coating subjected to tribological stresses is to crack and spall off. In this study, the influence on scratch behavior of a hard polyurethane coating on a plasticized PVC substrate has been investigated. At low load, the hard coating allows decreasing the plastic deformation of the substrate, and a geometrical interpretation is proposed. At increasing loads, this coating shows three fracture mechanisms: first, cracks oriented at 45° to the scratch direction starting near the detachment point behind the tip, on the edge of the scratch; then, in addition to this first mechanism, tearing under the tip forming a central crack parallel to the scratch direction; finally, in addition to the first two mechanisms, a circular crack forms ahead of the indentor by a bending effect at the top of the frontal bulge. These mechanisms are observed in situ thanks to a microscope coupled to a camera. Then, the scratches are observed by X-Ray tomography in order to analyze crack propagation in the depth of the material. Finally a numerical model of the scratch test has been developed. The combination of the three techniques gives a precise insight into the local mechanical conditions that lead up to these different kinds of scratches.

Research on Reliability of Packaging Materials for PVT Modules

This paper studies the difference in heat transfer and adhesion performance of glass fiber substrate thermal conductive double-sided adhesive, PVC substrate double-sided adhesive, and PET substrate double-sided adhesive to thermal conductive materials and polymer materials in photovoltaic and thermal integrated modules. Studies have shown that the use of glass fiber-based thermally conductive double-sided adhesive to bond polymer materials and thermally conductive materials can achieve the normal use of PVT modules under weather-resistant conditions. Research has shown that glass fiber-based thermally conductive double-sided adhesive has better adhesion than other materials., Initial viscosity, static shear force, thermal conductivity, etc., can realize the normal use of PVT modules under weathering conditions.

Unusual conductivity temperature dependence of multiwalled carbon nanotube thin film

The Multiwalled carbon nanotube (MWCNT) thin films has been formed on PVC substrate using Langmuir-Blodgett technique as highly promising material for optoelectronics. The layers were annealed at 367 K which has led to significant electrical resistance decrease. The resistance of the obtained layer was investigated in wide temperature range showing the dependence significantly different from that observed for the layers created using CNTs of smaller diameter. The reason of the unusual conductivity temperature dependence is most probably the difference in thermal expansion coefficients of MWCNTs and the polymer combined with relatively high stiffness of the nanotubes with such large diameter.

Evaluation of a passive method for determining particle penetration through protective clothing materials

ABSTRACTThe risk of workers' exposure to aerosolized particles has increased with the upsurge in the production of engineered nanomaterials. Currently, a whole-body standard test method for measuring particle penetration through protective clothing ensembles is not available. Those available for respirators neglect the most common challenges to ensembles, because they use active vacuum-based filtration, designed to simulate breathing, rather than the positive forces of wind experienced by workers. Thus, a passive method that measures wind-driven particle penetration through ensemble fabric has been developed and evaluated. The apparatus includes a multidomain magnetic passive aerosol sampler housed in a shrouded penetration cell. Performance evaluation was conducted in a recirculation aerosol wind tunnel using paramagnetic Fe3O4 (i.e., iron (II, III) oxide) particles for the challenge aerosol. The particles were collected on a PVC substrate and quantified using a computer-controlled scanning electron microscope. Particle penetration levels were determined by taking the ratio of the particle number collected on the substrate with a fabric (sample) to that without a fabric (control). Results for each fabric obtained by this passive method were compared to previous results from an automated vacuum-based active fractional efficiency tester (TSI 3160), which used sodium chloride particles as the challenge aerosol. Four nonwoven fabrics with a range of thicknesses, porosities, and air permeabilities were evaluated. Smoke tests and flow modeling showed the passive sampler shroud provided smooth (non-turbulent) air flow along the exterior of the sampler, such that disturbance of flow stream lines and distortion of the particle size distribution were reduced. Differences between the active and passive approaches were as high as 5.5-fold for the fabric with the lowest air permeability (0.00067 m/sec-Pa), suggesting the active method overestimated penetration in dense fabrics because the active method draws air at a constant flow rate regardless of the resistance of the test fabric. The passive method indicated greater sensitivity since penetration decreased in response to the increase in permeability.

Synthesis of AzPhchitosan-bifenthrin-PVC to protect cables against termites

The destruction of PVC cables by termites is a continuing and long-standing problem, which can lead to power leakage and power cut. Given the environmental demerits of insecticide overuse, alternative methods of addressing this problem are a highly desirable goal. In this study, we used photo-immobilization to develop a chitosan carrier system to help bifenthrin immobilize on the surface of the PVC substrate. The immobilization was analyzed using nuclear magnetic resonance (NMR), UV absorption, reverse-phase high-performance liquid chromatography (RP-HPLC), Raman absorption spectroscopy, and thermal gravimetric analysis (TGA). The surface structure and biological activity of the embedded and immobilized bifenthrin were examined using scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photon-electron spectroscopy (XPS). Its efficacy was assessed in pest experiments. The results indicate a successful embedding and immobilization of bifenthrin. Furthermore, the chemical bonding network between AzPhchitosan, bifenthrin, and PVC is stable, guaranteeing no environmental release of bifenthrin, and also providing more efficacious protection against termites. The evidence suggests that this photo-immobilization of bifenthrin-embedded chitosan on the surface of PVC substrates is a novel and environmentally friendly technique for termite control. This paper also reports a modification of chitosan with respect to its novel application in environmental protection.

Preparation and Properties of Double-Sided AgNWs/PVC/AgNWs Flexible Transparent Conductive Film by Dip-Coating Process.

The double-sided transparent conductive films of AgNWs/PVC/AgNWs using the silver nanowires and PVC substrate were fabricated by the dip-coating process followed by mechanical press treatment. The morphological and structural characteristics were investigated by scanning electron microscope (SEM) and atomic force microscope (AFM), the photoelectric properties and mechanical stability were measured by ultraviolet–visible spectroscopy (UV–vis) spectrophotometer, four-point probe technique, 3M sticky tape test, and cyclic bending test. The results indicate that the structure and photoelectric performances of the AgNWs films were mainly affected by the dipping and lifting speeds. At the optimized dipping speed of 50 mm/min and lifting speed of 100 mm/min, the AgNWs are evenly distributed on the surface of the PVC substrate, and the sheet resistance of AgNWs film on both sides of PVC is about 60 Ω/sq, and the optical transmittance is 84.55 % with the figure of merit value up to 35.8. The film treated with the 10 MPa pressure shows excellent adhesion and low surface roughness of 17.8 nm and maintains its conductivity with the sheet resistance change of 17 % over 10,000 cyclic bends.

UV grafting process for synthetic drag reduction of biomimetic riblet surfaces

ABSTRACTSkin–friction drag accounts for a large portion of resistance encountered by water‐based vehicles, such as ships and submarines. Developing drag reduction methods to improve drag reduction performance has drawn worldwide attention recently. UV‐induced polymerization has been investigated as a way to graft the drag reduction agent PAM on to a PVC substrate with a biomimetic riblet surface. The effects of AM concentration and irradiation time on the grafting rate were explored to determine optimal grafting parameters. UV grafting polymerization was clarified by comparing the peak absorption variation of the infrared spectrum before and after grafting. The PAM thin film grafted on riblet surface was measured approximately 10 µm in thickness. A rotating disk apparatus was built to measure the synthetic drag reduction performance. The drag reduction rate of the grafted PAM riblet surface was tested at approximately 14%, higher than the 6% of the traditional riblet surface. Moreover, the excellent drag reduction performance of grafted PDMS riblet surface lasted for 12 days. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42303.

Bionic Research on Bird Feather for Drag Reduction

To reduce friction drag with bionic method in a more feasible way, the surface microstructure of bird feather was analyzed attempting to reveal the biologic features responding to skin friction drag reduction. Then comparative bionic surface mimicking bird feather was fabricated through hot-rolling technology for drag reduction. The microriblet film was formed on a PVC substrate through a self-developed hot-rolling equipment. The bionic surface with micron-scale riblets formed spontaneously due to the elastic-plastic deformation of PVC in high temperature and high pressure environment. Comparative experiments between micro-structured bionic surface and smooth surface were performed in a wind tunnel to evaluate the effect of bionic surface on drag reduction, and significant drag reduction efficiency was obtained. Numerical simulation results show that microvortex induced in the solid-gas interface of bionic surface has the effect of shear stress reduction and the small level of an additional pressure drag resulting from pressure distribution deviation on bird feather like surface, hence reducing the skin friction drag significantly. Therefore, with remarkable drag reduction performance and simple fabrication technology, the proposed drag reduction technique shows the promise for practical applications.

Nanocoral ZnO films fabricated on flexible poly(vinyl chloride) using a carrier substrate

Nanocoral ZnO films on flexible poly(vinyl chloride) (PVC) were fabricated using a three step approach including (1) sputter deposition of a porous Zn film onto a sacrificial Si carrier substrate, (2) formation of the nanocoral ZnO film through annealing in an oxygen flow at temperatures greater than 400°C and (3) transfer of the film to an adhesive-coated PVC substrate with subsequent removal of the Si carrier. The proposed approach enables the fabrication of porous ZnO films requiring high temperature preparation on flexible polymer-based substrates which would otherwise degrade at high temperatures.

Adsorption characteristic of copper ions and its application in electroless nickel plating on a hydrogel-functionalized poly(vinyl chloride) plastic

A facile and palladium-free process for the electroless plating on poly(vinyl chloride) (PVC) plastic has been demonstrated. The process is based on the Cu adsorption capacity of semi-interpenetrating polymer network (semi-IPN) hydrogel chemically bonded to PVC surface via a simple and one-step approach that applying a chitosan/polyethylene glycol/glutaraldehyde system under mild stirring at room temperature. Therefore, electroless plating can be achieved in the following three steps, namely: (1) the functionalization of PVC by the semi-IPN hydrogel film (2) the adsorption and formation of the catalyst Cu0 on the PVC surface, and (3) the electroless nickel plating in plating bath. Batch adsorption experiments are conducted to determine the effects of pH, initial Cu2+ ions concentration and the dosage of crosslinking agent glutaraldehyde on copper adsorption and the surface resistance of the corresponding plated-PVC. The activated reaction progress and resulting nickel–phosphorus (Ni–P) layer were characterized by attenuated total reflection Fourier transform infrared, scanning electron microscopy, X-ray photoelectron spectroscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction. The results show that the Cu nanoparticles chemisorbed on the functionalized PVC substrate, could effectively initial the subsequent electroless nickel plating; and a compact and continuous Ni–P layer with amorphous phase was successfully deposited on PVC by this process. Besides, the surface resistance of the plated-PVC as low as 0.5 Ω sq−1 showed an excellent adhesion with the PVC substrate proved by Scotch-tape test.