Tetrafluoroethylene Films Research Articles

Engineering Highly Emissive Tetra(t‐Butyl)rubrene/off‐Stoichiometry Thiol‐Ene Hybrids Toward Flexible Luminescent Solar Concentrator‐Integrated Photovoltaics with Excellent Stability

Luminescent solar concentrators (LSCs) are highly valued in transparent photovoltaics for their versatility and adaptability as effective large‐area sunlight collectors. However, constructing LSCs as efficient, long‐term stable, and easily malleable power‐generating units still remains a challenge. Herein, high photostability, high photoluminescence quantum yield (ΦPL), and Stokes‐shifted emission are achieved in tetra(t‐butyl)rubrene/off‐stoichiometry thiol‐ene (TBRb/OSTE) hybrids by incorporating TBRb molecules into OSTE polymers. To demonstrate their potentials in LSCs, a luminescent solar concentrator integrated photovoltaics (LSCIPV) is created using a one‐step synthesis that combines the preparation of TBRb/OSTE hybrids, coupling with the silicon solar cell, and the encapsulation of both components. The LSCIPV demonstrates remarkable flexibility and the integration of an ethylene tetrafluoroethylene film contributes to a hydrophobic surface and antireflection effect, resulting in an external photon efficiency (ηext) of 4.9% and a power conversion efficiency of 1.04% for the 100 cm2 device. The LSCIPV exhibits good photostability over 800 h of UV light exposure. Monte Carlo ray‐tracing simulations indicate that an optimized TBRb‐based LSCIPV can potentially achieve an ηext of 1.3%, even for a large device with an area of 1 m2.

Adsorption of Cu (II) ions from aquatic environment using pre-irradiated Ethylene Tetrafluoroethylene Film

Although copper (Cu) is a very beneficial metal, having too much of it in the body can cause lung issues, severe anemia, nausea, and vomiting. In order to extract Cu (II) ions from aqueous solution, an adsorbent was constructed in this study employing pre-irradiation grafted Ethylene tetrafluoroethylene (ETFE) film. The grafting method was used to binary monomers of sodium styrene sulfonate (SSS) and acrylic acid (AA), where NaCl served as an additive. The grafted polymer was also subjected to studies of tensile strength, water uptake, surface area extension, Scanning Electron Microscopy (SEM), and Fourier Transform Infrared spectroscopy (FTIR). The adsorption of Cu (II) was investigated with respect to pH, starting metal ion concentrations, contact time, monomer concentrations, and temperature. With 50 kGy of radiation dose, 4% NaCl, and 30% of monomer solution (SSS:AA = 1:2) in water generated the highest graft yield of 470%. The maximum adsorption capacity (412 mg g−1) was discovered with an initial concentration of 2500 mg L−1, a pH of 4.86, and a contact time of 24 h at room temperature (25 ℃). A monolayer adsorption was recommended by the good linking between experimental data and the Langmuir Isotherm Model. The kinetic adsorption data closely fitted with the pseudo-second-order reaction. Due to its increased adsorption capacity and reusability, the synthesized new grafted polymer can be considered an efficient adsorbent for Cu (II) removal from wastewater.

Influence of Ageing on Optical, Mechanical, and Thermal Properties of Agricultural Films.

Plastic films utilized as greenhouse coverings play a vital role in safeguarding plantations from diverse weather conditions like sunlight, rain, hail, and wind. It is essential for these films to preserve their properties even after extended exposure to sunlight and water, while also maintaining transparency to support the unhindered growth of plants. The purpose of the study was to compare the properties of three types of plastic films: low density polyethylene diffuse film, low density polyethylene clear film, and ethylene tetrafluoroethylene film, before and after their ageing in weather test chamber with xenon-arc light in the presence of moisture. Two distinct types of PE films were chosen based on their suitability for specific regions in Croatia, whereas ETFE film was chosen as a potential new material that is gaining popularity across various industries, including agriculture. The properties investigated were tensile properties, transmittance by spectral analysis, and viscoelastic properties by dynamic mechanical analysis. Also, untreated films and the ones exposed to artificial ageing were compared by means of Fourier-transform infrared spectroscopy, differential scanning calorimetry and thermogravimetric analysis. The administered tests revealed a certain level of property degradation due to ageing in all three films. However, none of the films showed a substantial level of deterioration, indicating their suitability as greenhouse coverings.

Delamination detection on composite laminates using the modal displacement unevenness coefficient

This paper develops a new detection method taking the power function of the modal displacement curvature difference as a damage index to accurately identify the location and degree of the delamination. The 4-layer Poly Tetra Fluoro Ethylene films of size 0.02 m × 0.11 m are embedded between adjacent carbon fiber prepregs being 0.06 m and 0.115 m away from the left edge, respectively. The force-hammer excitation experiment is carried out on the prepared laminates with fixed supports at both ends, and the frequency response curves of measuring points are processed by the Polylscf algorithm in Dong-Hua Data Analysis System. The finite element model of delaminated laminates is established through adding new layers with film properties, and the modal displacements of nodes are compared with experimental data. The number of measuring points in the experiment is limited, making the precise characterization of surface abrupt characteristics difficult. The numerical results are used to calculate the square of the Gaussian curvature difference between the modal displacements of intact and damaged laminates. Significant improvement of the delamination detection accuracy is achieved in this process, confirming that the developed method constitutes a valuable tool for the Non-Destructive Testing of the laminates.

Selectively emissive fluoropolymer film for passive daytime radiative cooling

Passive daytime radiative cooling is an attractive method to reduce overheating and the heat island effect, thus addressing the global warming effect. This technology does not require any input energy, noise, vibrations, and polluting gas to produce sub-ambient temperatures. In this study, we propose a simple passive daytime radiative cooler, composed of a silver back layer and commercial ethylene tetrafluoroethylene film. With many molecular vibration peaks in the sky window and high solar transmittance of ethylene tetrafluoroethylene, the silver-deposited film exhibits only 3.5% solar absorption and 88.6% emissivity in the sky window, resulting in a substantial sub-ambient cooling effect of up to 9.7 °C in outdoor measurements. The theoretical prediction was confirmed to match well with experimental results, and the passive daytime radiative cooling ability of the film was examined using global-scale cooling energy density maps.

Lectrical Output and Reliability of Photovoltaic Module Using Ethylene Tetrafluoroethylene Film

lectrical Output and Reliability of Photovoltaic Module Using Ethylene Tetrafluoroethylene Film

Uniaxial deformation and orientation of ethylene–tetrafluoroethylene films

This study concerns the thermal and mechanical response of several commercial grades of ethylene – tetrafluoroethylene copolymer films. Differential scanning calorimetry was used to show that, although films have similar degrees of crystallinity and melting temperature, the melting endotherms and crystallisation exotherms differ between materials, suggesting small changes in composition between manufacturers. Films were deformed in tension at a range of temperatures and rates. Selected films were unloaded immediately after stretching, and measurement of the elastic recovery highlighted further differences between materials. Batches of films were pre-drawn uniaxially above the glass transition and immediately quenched. When these materials were subsequently re-drawn below the glass transition temperature, most of them exhibited much improved yield stress, modulus and tensile strength (improving by factors of 5, 5 and 4, respectively at a draw ratio of 3), but a reduced strain to failure. In most of the films, the pre-drawing, as well as the initial orientation of the films, is accounted for by a simple shift in the true strain axis. This is indicative of a material response dominated by entropic network stretch. It also suggests that, in the cases where strain superposition does not work, a different arrangement of crystalline lamellae may be present, limiting the extent to which improved properties can be achieved in some materials.

Glass–film-combination: Opto-physical properties and energy saving potential of a novel greenhouse glazing system

A combination of anti-reflection coated glass and ethylene tetrafluoroethylene film is introduced as a novel glazing system for greenhouses and similar buildings. It combines the advantages of the individual materials (durability/low weight; favourable condensation behaviour/self-cleaning) and of single and double layer systems (light transmission/insulation). By inflating/deflating the glass–film interspace, the additional insulation can be switched on and off. Since no standard method for this purpose is available, a hot box-system was developed to measure heat transfer coefficients (U-values) of different models of the glass–film-combination (GFC) and other commonly used greenhouse glazing materials at different surface inclinations; with or without condensation. Surface inclination did not greatly influence heat transfer. Condensation increased the U-values more pronounced for single layer-systems than for the GFC. Influences of wind velocity on heat transfer decreased with the degree of insulation. Overall, when mounted with adhesive tape, the energy efficiency of the GFC was 38% higher compared to customary float glass. The energy saving potential of plastic profile mounted GFC versions was 50% and 64% for the double and triple layer system (ETFE-film on both sides of the glass pane), respectively. PAR transmission of the GFC was similar to single pane float glass, its UV transmittance markedly higher.

Development Of Novel Biomimetic Membrane Designs For Separation And Biosensor Applications

Integral membrane proteins have a variety of functions e.g. as channels, transporters or receptors. In order to study transmembrane proteins under controlled circumstances they must be embedded into a matrix mimicking their in vivo environment. There has been a growing interest in developing a biomimetic platform technology for biosensor and separation applications.Current design criteria for free-spanning artificial membrane platform technologies are low leak membrane sealing, membrane stabilities above 1 day, absolute reproducibility, a scaffold consisting of multiple functional units, enablement of reconstitution of membrane spanning molecules, be robust for transportation and cost effective. For mass transfer flow and high throughput screening applications additional design criteria are required. These include a high perforation level of the membrane scaffold material, the functional membrane units are arranged in arrays to facilitate a screening platform (e.g. for microplate readers) and the artificial membrane platform is scalable to met various requirements for the individual technical applications.Recently, we have developed a model biomimetic membrane design and an automation technique for establishing multiple black lipid membranes (BLMs) in arrays of micro structured ethylene tetrafluoroethylene films, and supported by a micro porous material. Success rates for establishment of supported BLMs across multiple aperture arrays were above 95%.Currently, work is focused on characterization of nanoporous materials and surface modifications together with different lipid compositions. Furthermore, to develop methods for the encapsulation of established membranes and for the controlled incorporation and distribution of transmembrane proteins into such encapsulated biomimetic membranes. Combined this work aims to meet all of the current design criteria for free-spanning artificial membrane platforms.

Surface modification of ethylene‐co‐tetrafluoroethylene films by remote plasmas

AbstractThe surface modifications of ethylene‐co‐tetrafluoroethylene (ETFE) surfaces by six plasmas (direct H2, Ar, and O2 plasmas and remote H2, Ar, and O2 plasmas) were investigated with two questions in mind: (1) what plasma could effectively modify ETFE surfaces and (2) which of the CF2CF2 and CH2CH2 components in ETFE was selectively modified? The plasma exposure led to a weight loss from the ETFE surfaces and changes in the chemical composition on ETFE surfaces. The weight‐loss rate showed a strong dependence on what plasma was used for the modification. The remote H2 plasma led to the lowest rate of weight loss in the six plasma exposures, and the direct O2 plasma led to the highest rate of weight loss. During exposure to the plasmas, defluorination occurred, and two new C1s components [CH2CHFCH2 and CH2CH(OR)CFx, and CH2CHFCF2, CH2C(O)CFx, and CFxC(O)O] were formed on the modified ETFE surfaces. Defluorination was strongly influenced by what plasma was used for the modification. The remote H2 and Ar plasmas showed high defluorinations of 55 and 51%, respectively. The remote O2 plasma showed a low defluorination of only 25%. Conclusively, the remote H2 and Ar plasma exposure effectively modified ETFE surfaces. With the exposure of these surfaces to the remote H2 plasma, the CF2CF2 component was predominantly modified, rather than the CH2CH2 component. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2871–2882, 2002

Effects of photo-excitation and organic vapor treatment on vapor sorption behavior of sputtered fluoropolymer films

Investigation of sorption capacities for volatile organic compounds of radio-frequency-sputtered fluoropolymer films has revealed that they are affected by the applied voltage and by supplemental photo-excitation using ultraviolet light irradiation during sputtering. The photo-assisted effects of producing unsaturated carbons on the sputtered tetrafluoroethylene film are revealed by infrared, electron spin resonance, and X-ray photoelectron spectroscopies. Measurements of sorption capacities and computational chemical calculation for six-membered cyclic hydrocarbons revealed that the π-character of the solute molecule is a decisive molecular descriptor for sorption behavior of the sputtered fluoropolymers. The π-character of the sputtered fluoropolymer films can be enhanced by a photo-assisted effect, which can also increase the affinities for π-characterized solutes by π– π interaction. This is further clarified by the fact that the photo-assisted fluoropolymer film has a larger sorption capacity for highly π-conjugated double aromatic ring systems (C 10H 8): naphthalene than for slightly π-conjugated, but polar, isomer: azulene. It was also found that saturated organic vapor ( p-xylene and 2-butanone) sorption can enhance the sorption capacities of the sputtered fluoropolymer by restructuring induced by solvation and radical reaction.

Determination of surface structure and orientation of polymerized tetrafluoroethylene films by near-edge x-ray absorption fine structure, x-ray photoelectron spectroscopy, and static secondary ion mass spectrometry

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDetermination of surface structure and orientation of polymerized tetrafluoroethylene films by near-edge x-ray absorption fine structure, x-ray photoelectron spectroscopy, and static secondary ion mass spectrometryDavid G. Castner, Kenneth B. Lewis Jr., Daniel A. Fischer, Buddy D. Ratner, and John L. GlandCite this: Langmuir 1993, 9, 2, 537–542Publication Date (Print):February 1, 1993Publication History Published online1 May 2002Published inissue 1 February 1993https://doi.org/10.1021/la00026a029RIGHTS & PERMISSIONSArticle Views448Altmetric-Citations95LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (747 KB) Get e-Alerts Get e-Alerts

Molecular diffusion in plasma-polymerized tetrafluoroethylene

Diffusion of an array of molecules in micrometer-thick films of plasma-polymerized tetrafluoroethylene has been measured using an optical interferometric technique. The diffusivity is approximately independent of molecular size up to a molar volume of about 100 cm3 and drops rapidly for larger molecules. For much larger molecules no penetration of the films is observed. These results suggest that plasma-polymerized tetrafluoroethylene films are heavily cross linked and that this limits the size of the molecules that can penetrate the polymer. The temperature dependence and the molecular size dependence of the diffusivities are discussed in the context of free-volume theory.

Swelling of plasma-polymerized tetrafluoroethylene films

Swelling of micrometer thick-films of plasma-polymerized tetrafluoroethylene has been measured for a range of solvents using an optical-interferometric technique. For low gas-phase concentrations of the solvent, the swelling is found to correlate with the ionization potential of the solvent. Photo-thermal deflection spectroscopy of the films shows optical absorption in the infrared, which changes with exposure to different solvents. Both of these results suggest weak electron transfer from the solvent to the polymer as the dominant interaction mechanism.

Properties of micrometer-thick plasma-polymerized tetrafluoroethylene films

Several physical properties of thin plasma-polymerized films have been measured using a new fiber-optic-based technique. Films of plasma-polymerized tetrafluoroethylene (PPTFE) deposited on the end of an optical fiber form an optical cavity, the reflectivity of which is very sensitive to the film thickness. The fiber is used as an in situ monitor of the deposition rate in the plasma and, after removal from the plasma, the mechanical properties of the film can be measured. With this measurement technique the thermal expansion of the film normal to its surface as well as the swelling of the film when exposed to an array of organic solvents have been determined. A significantly smaller thermal-expansion coefficient and larger degree of swelling are observed relative to bulk PTFE. X-ray photoelectron spectroscopy measurements show that the fluorocarbon chains are highly branched and have a fluorine-to-carbon ratio of 1.45. These results suggest that the plasma-polymerized films are not crystalline and are heavily cross linked.

Dielectric Properties of Plasma-Polymerized Tetrafluoroethylene Films

A plasma-polymerized tetrafluoroethylene film has dielectric loss peaks below -50degC and approximately at 40degC. The effects of the substrate temperature during polymerization and of plasma irradiation after polymerization on the appearance of the peaks were studied. The low-temperature peak seems to be due to local-mode relaxation of polar groups, while the high-temperature peak seems to be due to phase transition.

Effect of Carrier Gas on Structure of Plasma Polymerized Tetrafluoroethylene Films

Thin films were polymerized by introducing tetrafluoroethylene gas into the “tail-flame” of a glow discharge of hydrogen or argon used as a carrier gas. Compared with argon, hydrogen gives a higher deposition rate at low discharge power and a lower rate at high discharge power. ESR, ESCA and IR measurements showed that films polymerized using hydrogen as a carrier gas are crosslinked to a higher degree and have more radicals than those polymerized using argon. The former films have higher tan δ values than the latter films. These results arise from the competing processes of polymerization and ablation in the glow-discharge plasma.

Permeation, diffusion and dissolution of hydrogen isotopes, methane and inert gases through/in a tetrafluoroethylene film

Tetrafluoroethylene (TFE) is widely used for conventional tritium handling systems such as vacuum seals, tubing and so on. We measured the permeation of the three hydrogen isotopes, methane and the inert gases through a TFE film at room temperature by means of the time-lag method in order to establish the physicochemical properties which determine the solubility and diffusivity of those gases. It was found that the diffusion constant of the inert gases changed exponentially with the heat of vaporization and the solubility was an exponential function of the Lennard-Jones force constant of the gases. On the other hand, hydrogen isotopes and methane deviated from these relations. It is concluded that chemical interactions between the solute and the solvent play an important role for the dissolution and the diffusion of these gases in TFE.

Hydrophobic coating of solid materials by plasma-polymerized thin film using tetrafluoroethylene (author's transl)

Glass slides were coated with plasma-polymerized tetrafluoroethylene films of different thickness using the glow discharge technique in a tube-shaped chamber, and the plasma conditions, film growth rates, light permeability of the polymer films, and particle bond strength in the polymer films were studied. Ashed sections of mouse organs and ashed bacillus spores were also coated to give them hydrophobic treatment without damaging their shapes or appearance. The hydrophobic coating of the specimens was successful, and the fine ash patterns were strongly fixed onto the glass slides, making permanent preparations.

Ion-etching of discharge-produced tetrafluoroethylene film with hydrogen, oxygen and noble gases. A mass spectrometric analysis

Freshly deposited discharge-produced tetrafluoroethylene films were ion-etched with either helium, neon, argon, oxygen or hydrogen. The ions C +, CF +, CF 2 + and CF 3 + comprised most of the positive ions in rare gas discharges, with CF + always dominant. Sputtered fragments containing two or more carbon atoms were rare. These findings are compatible with the ion-etching of a highly crosslinked polymer film. Residual background gases were contributed to 1–3% of the total ion flux even though their actual partial pressures were very low. The concentration of neutral species corresponding to the ions observed was less than one part in ten thousand of the etching gas. With pure hydrogen, very little etching occurred and the degree of ionization relative to the rare gases was low. The principal reaction was the abstraction of fluorine from the polymer to give hydrogen fluoride and a more highly crosslinked film. Oxygen containing discharges produced the largest total yield of all the systems studied and the most evidence of chemical attack on the polymer. The ions observed were CO +, CO 2 +, COF +, COF 2 + as well as C +, CF +, CF 2 + and CF 3 +. Thus oxygen etches the polymer by preferentially attacking the carbon-carbon framework.