Fluorinated Ethylene Propylene Research Articles

Simultaneous Cu(II)-EDTA decomplexation and Cu(II) recovery using integrated contact-electro-catalysis and capacitive deionization from electroplating wastewater

The complex of heavy metals and organic acids leads to high difficulty in heavy metals separation by traditional technologies. Meanwhile, alkaline precipitation commonly used in industry causes the great consumption of resources and extra pollution. Herein, the effective decomplexation of Cu(Ⅱ)-EDTA and synchronous recycling of Cu2+ were realized by contact-electro-catalysis (CEC) coupled with capacitive deionization (CDI) innovatively. In particular, fluorinated ethylene propylene (FEP) as dielectric powders could generate reactive oxygen species under ultrasonic stimulation, realizing continuous deaminization and decarboxylation of Cu(Ⅱ)-EDTA and accelerating the totally breakage of Cu-O and Cu-N bonds. Additionally, the degradation pathway and intermediates evolution of Cu(Ⅱ)-EDTA were investigated using various characterization methods. It was confirmed that decarboxylation predominantly governed the degradation process of Cu(Ⅱ)-EDTA in CEC. During the course of treatment, the degradation ratio of Cu(Ⅱ)-EDTA reached 86.4 % within 150 min. Impressively, this strategy had satisfactory applicability to other metal combinations and excellent cycle stability. Subsequently, the released Cu ions were captured by CuSe cathode electrode through CDI. This research elucidated the degradation mechanism of persistent organic pollutant during CEC, and provided a novel approach for efficiently treating industrial wastewater containing metal complexes and advancing the exploitation and utilization of new technologies for metal recovery.

A Hybrid Wind and Raindrop Energy Harvesting Operating on Savonius Turbine

In offshore environments, abundant wind and rainfall resources await development, representing significant untapped energy potential for powering Internet of Things (IoT) devices. Triboelectric Nanogenerators (TENGs) are particularly suited for capturing continuous motion in offshore environments, presenting a reliable solution for sustainable energy generation in IoT applications. Herein, we propose a wind-droplet hybrid generator (WDHG) tailored for adaptive environmental energy harvesting, explicitly targeting the demanding conditions prevalent in offshore environments. The WDHG combines the efficiency of a helical Savonius TENG with the versatility of an interdigitated electrode TENG, enabling simultaneous wind and rain energy harvesting. The helical Savonius TENG exhibits superior aerodynamic performance, producing an output power ranging from 0.39 to 2.10mW with wind speeds increasing from 0.75 to 6.84m/s. Additionally, the droplet TENG generates a power output of 35.90mW/m2 under rainfall at 70mm/min. Optimizations include not only the comparative analysis of helical Savonius turbines and the variation in pole-pair numbers but also adjustments in fluorinated ethylene propylene (FEP) film thickness and electrode gap length for interdigitated electrode, alongside the development of a tailored power management circuit (PMC) featuring dual bridge rectifiers, a buck circuit module, and a smart load switch. The PMC enables continuous operation of a low-powered digital thermohygrometer under conditions of 4.5m/s wind speed, and drives a 20-second wake BLE server under 7.2m/s wind speeds. Integration of the WDHG with offshore wind and raindrop extends energy harvesting capabilities, exhibiting a great potential of providing reliable power source for IoT devices.

An Anthocyanin-Based Eco-Friendly Triboelectric Nanogenerator for pH Monitoring and Energy Harvesting.

In recent years, renewable and sustainable triboelectric nanogenerators have attracted attention due to their high energy conversion rate, and enhancing their functionality further contributes to their applicability across various fields. A pH-sensitive triboelectric nanogenerator (pH-TENG) has been prepared by electrostatic spinning technology, with anthocyanin as the pH indicator and environmentally friendly polyvinyl alcohol (PVA) as the substrate. Among many friction-negative materials, the pH-TENG exhibits the best combination with fluorinated ethylene propylene (FEP) and yields an open-circuit voltage of 62 V, a short-circuit current of 370 nA, and a transferred charge of 21.8 nC. At a frequency of 3 Hz, it can charge a 4.7 μF capacitor to 2 V within 45 s, effectively powering a thermometer. Furthermore, the presence of anthocyanin does not affect the pH-TENG's power generation performance and enables the monitoring of a wide range of environmental pH changes, with an ΔE change of 28.8 ± 7.6. Therefore, pH-TENG prepared with environmentally friendly materials can bring new available materials to the biological and medical fields.

Enhancing the performance of triboelectric nanogenerator via chitosan films surface modification

The triboelectric nanogenerator (TENG) has enormous application prospects and research value in energy collection due to its small size, simple structure, and ability to convert mechanical energy into electrical energy output. The microstructure of TENG’s friction layer has a significant impact on its output performance. We, herein, propose a surface modification method by replicating the surface morphology of sandpaper to construct microstructure on the surface of chitosan film or by constructing porous structure using electrospinning technology. Thanks to the significant increase in the effective contact area between the two friction materials, the output performance of the vertical contact-separation TENG with chitosan (Fluorinated ethylene propylene) film being used as a friction positive (negative) material is greatly enhanced. This TENG also exhibits its sensitivity in perceiving human movements and has good power supply capabilities. Our results indicate that surface modification of the friction materials is a facile strategy to boost the performance of TENG.

Contact‐Electro‐Catalysis for Direct Oxidation of Methane under Ambient Conditions

AbstractThe conversion of methane under ambient conditions has attracted significant attention. Although advancements have been made using active oxygen species from photo‐ and electro‐ chemical processes, challenges such as complex catalyst design, costly oxidants, and unwanted byproducts remain. This study exploits the concept of contact‐electro‐catalysis, initiating chemical reactions through charge exchange at a solid–liquid interface, to report a novel process for directly converting methane under ambient conditions. Utilizing the electrification of commercially available Fluorinated Ethylene Propylene (FEP) with water under ultrasound, we demonstrate how this interaction promote the activation of methane and oxygen molecules. Our results show that the yield of HCHO and CH3OH can reach 467.5 and 151.2 μmol ⋅ gcat−1, respectively. We utilized electron paramagnetic resonance (EPR) to confirm the evolution of hydroxyl radicals (⋅OH) and superoxide radicals (⋅OOH). Isotope mass spectrometry (MS) was employed to analyze the elemental origin of CH3OH, which can be further oxidized to HCHO. Additionally, we conducted density functional theory (DFT) simulations to assess the reaction energies of FEP with H2O, O2, and CH4 under these conditions. The implications of this methodology, with its potential applicability to a wider array of gas‐phase catalytic reactions, underscore a significant advance in catalysis.

Contact-Electro-Catalysis for Direct Oxidation of Methane under Ambient Conditions.

The conversion of methane under ambient conditions has attracted significant attention. Although advancements have been made using active oxygen species from photo- and electro- chemical processes, challenges such as complex catalyst design, costly oxidants, and unwanted byproducts remain. This study exploits the concept of contact-electro-catalysis, initiating chemical reactions through charge exchange at a solid-liquid interface, to report a novel process for directly converting methane under ambient conditions. Utilizing the electrification of commercially available Fluorinated Ethylene Propylene (FEP) with water under ultrasound, we demonstrate how this interaction promote the activation of methane and oxygen molecules. Our results show that the yield of HCHO and CH3OH can reach 467.5 and 151.2 μmol ⋅ gcat -1, respectively. We utilized electron paramagnetic resonance (EPR) to confirm the evolution of hydroxyl radicals (⋅OH) and superoxide radicals (⋅OOH). Isotope mass spectrometry (MS) was employed to analyze the elemental origin of CH3OH, which can be further oxidized to HCHO. Additionally, we conducted density functional theory (DFT) simulations to assess the reaction energies of FEP with H2O, O2, and CH4 under these conditions. The implications of this methodology, with its potential applicability to a wider array of gas-phase catalytic reactions, underscore a significant advance in catalysis.

A Flexible, Adaptive, and Self-Powered Triboelectric Vibration Sensor with Conductive Sponge-Silicone for Machinery Condition Monitoring.

Vibration sensors for continuous and reliable condition monitoring of mechanical equipment, especially detection points of curved surfaces, remain a great challenge and are highly desired. Herein, a highly flexible and adaptive triboelectric vibration sensor for high-fidelity and continuous monitoring of mechanical vibration conditions is proposed. The sensor is entirely composed of flexible materials. It consists of a conductive sponge-silicone layer and a fluorinated ethylene propylene film. It can detect vibration acceleration of 5 to 50 m s-2 and vibration frequency of 10 to 100Hz. It has strong robustness and stability, and the output performance barely changes after the durability test of 168000 working cycles. Additionally, the flexible sensor can work even when the detection point of the mechanical equipment is curved, and the linear fit of the output voltage and acceleration is very close to that when the detection point is flat. Finally, it can be applied to monitoring the working condition of blower and vehicle engine, and can transmit vibration signal to mobile phone application through Wi-Fi module for real-time monitoring. The flexible triboelectric vibration sensor is expected to provide a practical paradigm for smart, green, and sustainable wireless sensor system in the era of Internet of Things.

A novel method to efficiently differentiate human osteoclasts from blood-derived monocytes

BackgroundOsteoclasts are the tissue-specific macrophage population of the bone and unique in their bone-resorbing activity. Hence, they are fundamental for bone physiology in health and disease. However, efficient protocols for the isolation and study of primary human osteoclasts are scarce. In this study, we aimed to establish a protocol, which enables the efficient differentiation of functional human osteoclasts from monocytes.ResultsHuman monocytes were isolated through a double-density gradient from donor blood. Compared to standard differentiation schemes in polystyrene cell culture dishes, the yield of multinuclear osteoclasts was significantly increased upon initial differentiation of monocytes to macrophages in fluorinated ethylene propylene (FEP) Teflon bags. This initial differentiation phase was then followed by the development of terminal osteoclasts by addition of Receptor Activator of NF-κB Ligand (RANKL). High concentrations of RANKL and Macrophage colony-stimulating factor (M-CSF) as well as an intermediate cell density further supported efficient cell differentiation. The generated cells were highly positive for CD45, CD14 as well as the osteoclast markers CD51/ITGAV and Cathepsin K/CTSK, thus identifying them as osteoclasts. The bone resorption of the osteoclasts was significantly increased when the cells were differentiated from macrophages derived from Teflon bags compared to macrophages derived from conventional cell culture plates.ConclusionOur study has established a novel protocol for the isolation of primary human osteoclasts that improves osteoclastogenesis in comparison to the conventionally used cultivation approach.

Absorption of volatile organic compounds (VOCs) by polymer tubing: implications for indoor air and use as a simple gas-phase volatility separation technique

Abstract. Previous studies have demonstrated volatility-dependent absorption of gas-phase volatile organic compounds (VOCs) to Teflon and other polymers. Polymer–VOC interactions are relevant for atmospheric chemistry sampling, as gas–wall partitioning in polymer tubing can cause delays and biases during measurements. They are also relevant to the study of indoor chemistry, where polymer-based materials are abundant (e.g., carpets and paints). In this work, we quantify the absorptive capacities of multiple tubing materials, including four nonconductive polymers (important for gas sampling and indoor air quality), four electrically conductive polymers and two commercial steel coatings (for gas and particle sampling). We compare their performance to previously characterized materials. To quantify the absorptive capacities, we expose the tubing to a series of ketones in the volatility range 104–109 µg m−3 and monitor transmission. For slow-diffusion polymers (e.g., perfluoroalkoxy alkane (PFA) Teflon and nylon), absorption is limited to a thin surface layer, and a single-layer absorption model can fit the data well. For fast-diffusion polymers (e.g., polyethylene and conductive silicone), a larger depth of the polymer is available for diffusion, and a multilayer absorption model is needed. The multilayer model allows fitting solid-phase diffusion coefficients for different materials, which range from 4×10-9 to 4×10-7 cm2 s−1. These diffusion coefficients are ∼ 8 orders of magnitude larger than literature values for fluorinated ethylene propylene (FEP) Teflon film. This enormous difference explains the differences in VOC absorption measured here. We fit an equivalent absorptive mass (CW, µg m−3) for each absorptive material. We found PFA to be the least absorptive, with CW ∼ 105 µg m−3, and conductive silicone to be the most absorptive, with CW ∼ 1013 µg m−3. PFA transmits VOCs easily and intermediate-volatility species (IVOCs) with quantifiable delays. In contrast, conductive silicone tubing transmits only the most volatile VOCs, denuding all lower-volatility species. Semi-volatile species (SVOCs) are very difficult to sample quantitatively through any tubing material. We demonstrate a system combining several slow- and fast-diffusion tubing materials that can be used to separate a mixture of VOCs into volatility classes. New conductive silicone tubing contaminated the gas stream with siloxanes, but this effect was reduced 10 000-fold for aged tubing, while maintaining the same absorptive properties. SilcoNert (tested in this work) and Silonite (tested in previous work) steel coatings showed gas transmission that was almost as good as PFA, but since they undergo adsorption, their delay times may be humidity- and concentration-dependent.

Evolution of the structural parameters and magnetic characteristics in “ferrite/polymer” nanocomposites

Binary and ternary composites based on soft magnetic spinels CoFe2O4 (or CFO) and Ni0.4Cu0.2Zn0.4Fe2O4 (or NCZFO) were produced. Binary CFO/NCZFO ceramic composite was consist of two magnetic phases with 1:1 ratio. Ternary CFO:FEP, NCZFO:FEP and [CFO/NCZFO]:FEP composites were produced by the thermal pressing of the initial ceramic powders (20 wt%) and fluorinated ethylene propylene – FEP (80 wt%). XRD, SEM and VSM investigation were carried out. The impact of the chemical composition and phase ratio of the composites on crystal structure, microstructure and magnetic properties were established. Magnetic measurements were performed at 300 and 10 K in the fields up to 70 kOe. It was demonstrated the synergetic effect for ceramic composite with the violation of the principle of additivity in two-phase ceramic composites.

High-Efficiency Polishing of Polymer Surface Using Catalyst-Referred Etching

Previously, we developed an abrasive-free polishing technique called catalyst-referred etching (CARE) for inorganic materials. In this method, the topmost site of the workpiece surface is preferentially removed via an indirect hydrolysis reaction promoted by a metal catalyst. In this study, we proposed applying the CARE method to polymer material polishing and demonstrated the polishing characteristics. Using the CARE method, polycarbonate, which has an easy cleavage of ester bond via hydrolysis, was polished, resulting in the smoothness of the surface roughness below 1.0 nm. Based on the surface observations, the removal mechanism was estimated as follows. Molecule chains are entangled to form clusters constituting the polymer surface and help determine the surface roughness. In the CARE method, the top of this cluster was selectively removed, thus creating a smooth surface. Polymers with C–C bonds, such as polymethyl methacrylate and fluorinated ethylene propylene, were also smoothed using the CARE method. These results indicate that the CARE method is highly effective in polishing polymer materials.

Structural and electrodynamic characteristics of the spinel-based composite system

Two- and tree-component spinel-polymer composites were produced by thermal pressing. The initial components were chosen as CoFe2O4 and Ni0.4Cu0.2Zn0.4Fe2O4 spinels that were produced using the sol-gel method. The ratio between spinel phases varied from 1:3 to 3:1. As a polymer, fluorinated ethylene propylene was used. The concentration of the spinels in the polymer matrix was fixed at 20 mass.%. Using XRD, SEM, and high-frequency spectroscopy, the correlation between the composition, structure, and electrodynamic characteristics of composites was established. It was found that the parameters of the unit cell of ferrite fillers do not change when filling the polymer. The RL values for the initial CoFe2O4/FEP and Ni0.4Cu0.2Zn0.4Fe2O4/FEP were in the range of −14.5 … -24.2 dB and −10.4 … -14.1 dB, respectively, which is lower than for ferrites without a polymer matrix. The maximum values of RL (as a module) were marked for CoFe2O4/FEP. Obtained values of the reflection loss coefficient in the range of 5–10 GHz open broad perspectives for the development of materials for electromagnetic absorption and 5G technology.

Sustainable energy harvesting and breath sensing with electrospun triboelectric nylon-6

A high-performance triboelectric nanogenerator (TENG) has been developed for breath sensing applications, utilizing tribopositive electrospun nylon-6 nanofibers and tribonegative fluorinated ethylene propylene (FEP). The optimization toward the development of electrospun nylon-6-based TENG includes a range of factors such as the applied force and frequency on tribo responses, the thickness of the fiber mat, the concentration of nylon-6 in the fiber mats, and the selection of the tribonegative material for pairing with nylon-6 nanofiber. Among these parameters, the nanofiber prepared with 18 wt% nylon-6, characterized by a uniform fiber distribution, the highest surface area of 55.69 m2 g−1, and an optimal thickness of 0.169 mm, demonstrated excellent TENG performance, among others. The TENG module constructed using nanofiber in a 4 cm2 area showed the TENG responses of more than 30 μA short-circuit current, 200 V open-circuit voltage, and 90 nC charge when hand-pressed. It achieved a substantial power density of 890 mW m−2 at 20 MΩ by applying a constant force of 10 N at a 10 Hz frequency. Charging a 1 μF capacitor to approximately 30.1 V in just 30 s highlights the potential of electrospun nylon-6 as a promising material for nanogenerator energy harvesting and sensing applications. The TENG device was found to be sufficient to power small, portable electronics such as LEDs and digital watch displays. A wearable belt was fabricated to showcase its breath-sensing capabilities by pairing it with FEP. The microcontroller connected to the TENG in the wearable belt is used to analyze the output produced through breathing patterns, subsequently activating a buzzer and LED by the nature of the breathing.

Grid-free touch recognition on arbitrary surface using triboelectric vibration sensor

Touch panels are extensively applied across various fields, serving as a critical platform for the future of human-machine interaction and the metaverse. However, touch panel development is impeded by complicated sensor systems, including electrode grids, stacked multilayers, and external power. Here, a highly sensitive self-powered vibration sensor based on the triboelectric nanogenerator (VS-TENG) is designed to realize grid-free touch recognition on arbitrary surfaces by detecting and locating an external vibration source. The VS-TENG adopts a sensing structure composed of a dual-layer copper electrode designed with a parametric surface and a fluorinated ethylene propylene (FEP) film, enabling the detection of vibrations within the frequency range of 1–4500 Hz and sub-micron low-amplitude vibrations. The dual-layer electrode structure is beneficial to resist the interference from external environment. The output performance of the VS-TENG under various vibration frequencies, amplitudes, and directions, as well as its sensing capabilities when installed on panels of different materials and shapes, are systematically analyzed. The touch panel based on the VS-TENG can easily rearrange the touch resolution according to given scenarios without any physical modification to the sensor, enabling game control and vivid handwriting. This highlights its significant potential for diverse applications in the future metaverse.

Experimental demonstration of the electrostatic induction and contact electrification for the ventilator-like of rotary nanogeneration

A fluorinated ethylene propylene (FEP) ring tube embedded in the bottom of ventilator to harvest additionally mechanical energy is introduced for hybrid inductive/triboelectric nanogenerator (H-TENG). First, charging glass bead moving closed to acrylic plane has distinctly identified for inductive polarities. Relationships between the moving speed on bead, charging bead amount and bead material with acrylic thickness have been thoroughly investigated. Results reveal that not only high moving speed but also bead charging and thin thickness enhance power output which possesses potential application for energy generation and self-powered sensor. Based on these results, the optimal H-TENG device combined with appropriate number of glass beads which conjuncts with three sets of electric brushes and heigh rotating speed enable to light up 121 LED lights. This study presents the inductive/triboelectricity mechanism of H-TENG by solid-dielectric base of rotating structure and inspires many imaginations of for harvesting large scale energy in the future.

Defect Passivation Toward Designing High‐Performance Fluorinated Polymers for Liquid–Solid Contact‐Electrification and Contact‐Electro‐Catalysis

AbstractContact‐electrification at solid–liquid interfaces (SL‐CE) and contact‐electro‐catalysis (CEC) are two blooming research areas with promising applications in sustainable energy, sensing, and chemical processes. However, prior research has neglected the impact of electronic defects on the ability of high‐performance tribo‐materials, like fluorinated polymers, to perform SL‐CE/CEC. Here, through first‐principle calculations, the addition of surface functional groups to fluorinated ethylene propylene (FEP) enables the tuning of its molecular orbitals' positions, and displacing deep‐level defect states from the HOMO‐LUMO gap is shown. Thereafter, FEP films are modified accordingly by plasma etching; resulting in a significant performance improvement of up to 202% (charge) in SL‐CE experiments, and up to 398% (kinetic rate) in CEC dye degradation. This study provides a theoretical and experimental framework to design high‐performance materials for SL‐CE and CEC, and insights into their physical mechanisms and defect passivation, which are all fundamental for the advancement of these fields.

Fluorinated ethylene propylene (FEP)/graphene nanoplatelet (GNP) nanocomposites as outstanding EMI shielding and heat dissipation material

Fluorinated ethylene propylene (FEP)/graphene nanoplatelet (GNP) nanocomposites as outstanding EMI shielding and heat dissipation material

How well does your e-nose detect cancer? Application of artificial breath analysis for performance assessment

Comparing electronic nose (e-nose) performance is a challenging task because of a lack of standardised method. This paper proposes a method for defining and quantifying an indicator of the effectiveness of multi-sensor systems in detecting cancers by artificial breath analysis. To build this method, an evaluation of the performances of an array of metal oxide sensors built for use as a lung cancer screening tool was conducted. Breath from 20 healthy volunteers has been sampled in fluorinated ethylene propylene sampling bags. These healthy samples were analysed with and without the addition of nine volatile organic compound (VOC) cancer biomarkers, chosen from literature. The concentration of the VOC added was done in increasing amounts. The more VOC were added, the better the discrimination between ‘healthy’ samples (breath without additives) and ‘cancer’ samples (breath with additives) was. By determining at which level of concentration the e-nose fails to reliably discriminate between the two groups, we estimate its ability to well predict the presence of the disease or not in a realistic situation. In this work, a home-made e-nose is put to the test. The results underline that the biomarkers need to be about 5.3 times higher in concentration than in real breath for the home-made nose to tell the difference between groups with a sufficient confidence.

Two-step ion beam treatment for superhydrophilic fluorinated polymers

Plasma treatment is a widely used simple and ecofriendly method to improve the surface wettability of polymers. However, this is challenging for fluorinated polymers because of their robust CF bonds with low surface energies. Here, we demonstrated a simple approach, involving Ar-H2 and O2-H2 two-step ion beam treatments, to achieve superhydrophilic fluorinated polymer surfaces. The effects of surface roughness and chemical composition on the water contact angle (WCA) were studied using X-ray photoelectron spectroscopy, scanning electron microscopy, and atomic force microscopy. After the single H2 ion beam treatment on fluorinated ethylene propylene films, the WCA decreased from 110.2° to 35.2° due to defluorination and oxidation effects. However, the H2 ion beam treatment alone has a limited effect on the root-mean-square (RMS) roughness, which hinders achieving superhydrophilicity. In contrast, the WCA significantly decreased to 1.3° and 1.2°, respectively after the Ar-H2 and O2-H2 two-step ion beam treatments. Although the chemical composition after these treatments was similar to that after the single H2 ion beam treatment, the RMS roughness increased upon the Ar and O2 ion beam treatments because of the formation of nanostructures. Our results show that nanostructures with abundant polar oxygen bonds are required to obtain superhydrophilic surfaces in fluorinated polymers.

Human mesenchymal stromal cell adhesion and expansion on fluoropolymer surfaces modified with oxygen and nitrogen-rich plasma polymers

Fluorinated ethylene propylene (FEP) vessels are of significant interest for therapeutic cell biomanufacturing applications due to their chemical inertness, hydrophobic surface, and high oxygen permeability. However, these properties also limit the adhesion and survival of anchorage-dependent cells. Here, we develop novel plasma polymer coatings to modify FEP surfaces, enhancing the adhesion and expansion of human mesenchymal stromal cells (hMSCs). Similar to commercially available tissue culture polystyrene vessels, oxygen-rich or nitrogen-rich surface chemistries can be achieved using this approach. While steam sterilization increased the roughness of the coatings and altered the surface chemistry, the overall wettability and oxygen or nitrogen-rich nature of the coatings were maintained. In the absence of proteins during initial cell attachment, cells adhered to surfaces even in the presence of chelators, whereas adhesion was abrogated with chelator in a protein-containing medium, suggesting that integrin-mediated adhesion predominates over physicochemical tethering in normal protein-containing cell seeding conditions. Albumin adsorption was more elevated on nitrogen-rich coatings compared to the oxygen-rich coatings, which was correlated with a higher extent of hMSC expansion after 3 days. Both the oxygen and nitrogen-rich coatings significantly improved hMSC adhesion and expansion compared to untreated FEP. FEP surfaces with nitrogen-rich coatings were practically equivalent to commercially available standard tissue culture-treated polystyrene surfaces in terms of hMSC yields. Plasma polymer coatings show significant promise in expanding the potential usage of FEP-based culture vessels for cell therapy applications.