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1
Iwamori, Satoru. "Adhesion and Friction Properties of Fluorocarbon Polymer Thin Films Coated onto Metal Substrates." Key Engineering Materials 384 (June 2008): 311–20. http://dx.doi.org/10.4028/www.scientific.net/kem.384.311.
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Poly(tetrafluoroethylene)(PTFE) thin films were coated onto metal substrates by a spin coat apparatus, vacuum evaporator and RF sputtering, and their adhesion and friction properties evaluated. PTFE thin film coated onto nickel-titanium (Ni-Ti) substrate by spin coating showed a low friction coefficient, however pull strength between the thin film and Ni-Ti substrate was low. In order to increase the pull strength, PTFE and poly(vinyl alcohol) (PVA) composite thin films were introduced between the PTFE thin film and Ni-Ti substrate by spin coating. PTFE thin film was also coated onto SUS302 substrate by a vacuum evaporator. This PTFE thin film showed poor adhesion to the SUS302 substrate. The adhesion was enhanced by heating of the substrate during the evaporation. In addition, a PTFE and ethylene vinyl alcohol (EVOH) composite thin film showed higher adhesion strength than that of the PTFE thin film. Poly(fluorocarbon) thin films were prepared by a conventional RF sputtering with PTFE target. These thin films showed a higher friction coefficient than that of the pristine PTFE. Molecular structures of the poly(fluorocarbon) thin films prepared by RF sputtering were different from the pristine PTFE. This difference may have influenced the friction coefficient. The pull strength of metal thin films such as gold, copper, nickel and aluminum deposited on the sputtered PTFE thin films by vacuum evaporation was measured. The nickel thin film adhered to the PTFE thin film most strongly of all the thin films.
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Lim, Seohee, and Jin-Soo Park. "Composite Membranes Using Hydrophilized Porous Substrates for Hydrogen Based Energy Conversion." Energies 13, no. 22 (2020): 6101. http://dx.doi.org/10.3390/en13226101.
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Poly(tetrafluoroethylene) (PTFE) porous substrate-reinforced composite membranes for energy conversion technologies are prepared and characterized. In particular, we develop a new hydrophilic treatment method by in-situ biomimetic silicification for PTFE substrates having high porosity (60–80%) since it is difficult to impregnate ionomer into strongly hydrophobic PTFE porous substrates for the preparation of composite membranes. The thinner substrate having ~5 μm treated by the gallic acid/(3-trimethoxysilylpropyl)diethylenetriamine solution with the incubation time of 30 min shows the best hydrophilic treatment result in terms of contact angle. In addition, the composite membranes using the porous substrates show the highest proton conductivity and the lowest water uptake and swelling ratio. Membrane-electrode assemblies (MEAs) using the composite membranes (thinner and lower proton conductivity) and Nafion 212 (thicker and higher proton conductivity), which have similar areal resistance, are compared in I–V polarization curves. The I–V polarization curves of two MEAs in activation and Ohmic region are very identical. However, higher mass transport limitation is observed for Nafion 212 since the composite membrane with less thickness than Nafion 212 would result in higher back diffusion of water and mitigate cathode flooding.
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Wang, Hao, Fuming Zhou, Jianming Guo, Yuanyuan Zhang, Hui Yang, and Qilong Zhang. "Surface-modified Zn0.5Ti0.5NbO4 particles filled polytetrafluoroethylene composite with extremely low dielectric loss and stable temperature dependence." Journal of Advanced Ceramics 9, no. 6 (2020): 726–38. http://dx.doi.org/10.1007/s40145-020-0409-2.
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AbstractPolymer-ceramic composites are widely applied in microwave substrate materials due to the excellent dielectric properties and simple preparation process recently. Polytetrafluoroethylene-based (PTFE) composites filled with Zn0.5Ti0.5NbO4 (ZTN) ceramic particles were fabricated by hot-pressing. The particles were modified by C14H19F13O3Si to enhance the interface compatibility between PTFE and ZTN powders, which was characterized by X-ray photoelectron spectroscopy (XPS) and contact angle. The surface characteristic of particles transformed into hydrophobicity and tight microstructure as well as better dielectric properties were obtained after the surface modification. The microstructure, dielectric, thermal, mechanical properties, and water absorption of the composites concerning ZTN content were investigated. Modified ZTN/PTFE composites with 50 vol% ZTN particles exhibit excellent dielectric properties with a high dielectric constant of 8.3, an extremely low dielectric loss of 0.00055 at 7 GHz, and a stable temperature coefficient of the dielectric constant of −12.2 ppm/°C. All the properties show modified ZTN particles filled PTFE composite is the potential material for microwave substrate application.
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Shao, Hui, Huan Ru Zhang, Qi Zhang, Guang Lu Han, Ruo Yu Chen, and Jing Zhong. "Preparation of NaA/PTFE Composite Membrane for Separation of DMF/H2O Mixture by Pervaporation." Advanced Materials Research 239-242 (May 2011): 2624–27. http://dx.doi.org/10.4028/www.scientific.net/amr.239-242.2624.
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The NaA/PTFE composite membranes were synthesized on polytetrafluoroethylene (PTFE) film by hydrothermal secondary growth (HSG) method and scratching (ST) method. The structure and morphology were characterized by XRD and SEM. The pervaporation(PV) performance of NaA/PTFE composite membranes were evaluated with dimethylformamide (DMF)/water mixtures. The XRD results showed that NaA/PTFE composite membranes kept the zeolite crystal feature of A type. The substrate, PTFE and zeolite were firmly combined together by the SEM photos. The results of PV showed that the flux and the separation factor of NaA/PTFE composite membrane prepared by HSG method with 4 crystallization times were 0.54 kg/m2 h and 23, respectively. The flux of NaA/PTFE composite membrane prepared by ST method was much larger than that of NaA/PTFE composite membrane prepared by HSG method, but separation factor was lower.
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Hou, Jun Ying, Song Rui Wang, and Zhi Wei Zhou. "The Effect of Ni-P Alloy Pre-Plating on the Performance of Ni-P/Ni-P-PTFE Composite Coatings." Key Engineering Materials 561 (July 2013): 537–41. http://dx.doi.org/10.4028/www.scientific.net/kem.561.537.
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In order to obtain more excellent performance of composite coating, a layer of Ni-P alloy was plated firstly, then Ni-P-PTFE composite coatings was plated. If plating time ratio of electroless plating Ni-P alloy and Ni-P-PTFE composite plating was properlly controlled, performance of pure Ni-P-PTFE composite coating could be improved. The study have shown that the total plating time is 2 hours, and the plating time ratio is 1:1, and good bonding strength with the substrate, right hardness, low friction coefficient, good corrosion resistance of Ni-P /Ni-P-PTFE composite coatings have been obtained.
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Insiyanda, Dita Rama, Fredina Destyorini, and Nanik Indayaningsih. "Detection of Polytetrafluoroethylene Coating Deposition in Carbon Composite Paper Surface PEMFC Using FTIR-ATR." Materials Science Forum 880 (November 2016): 114–18. http://dx.doi.org/10.4028/www.scientific.net/msf.880.114.
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Spectroscopy Fourier Transform Infrared (FTIR) – Attenuated Total Reflectance (ATR) used to study the surface of polymeric materials on polymeric substrates using a sensitive technique for chemical profiling, study of reflection spectroscopy, and a non-invasive. In this study we will investigate of Polytetrafluoroethylene (PTFE) deposition in carbon composite paper without damaging its structure by FTIR-ATR. Carbon composite paper was prepared by mixing the carbon material from coconut fiber and polymer binder in xylen as solvent, casted on glass substrate, and then rolled to make a sheet. Coating process was done by dipped the carbon composite paper in the PTFE suspension with different content of 10 wt%, 20 wt% and 30 wt% for 30 minutes and dried at room temperature for one night and heated at 150°C for 30 minutes, and finally heated at 350°C for 30 minutes to melt the PTFE. All samples were analyzed by using FTIR-ATR and SEM-EDS. Deposition of PTFE with different content in carbon composite papers could be observed by FTIR-ATR. The peaks located at near 1205 cm-1 and 1154cm-1 with different intensity for each PTFE contents. FTIR-ATR could be used as a pre-detection method of PTFE deposition in carbon composite paper before using SEM-EDS, because FTIR-ATR would be reflected at the highly reflective surface.
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Li, Xiao, Xiao-Xiong Wang, Tian-Tian Yue, et al. "Waterproof-breathable PTFE nano- and Microfiber Membrane as High Efficiency PM2.5 Filter." Polymers 11, no. 4 (2019): 590. http://dx.doi.org/10.3390/polym11040590.
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This study shows the feasibility of using electrospinning technique to prepare polytetrafluoroethylene/poly (vinyl alcohol) (PTFE/PVA) nanofibers on PTFE microfiber membrane as substrate. Then, PVA in the fiber membrane was removed by thermal treatment at about 350 °C. Compared to PTFE microfiber substrates, the composite PTFE fiber membranes (CPFMs) have improved filtration efficiency by 70% and water contact angle by 23°. Experimental test data showed that the water contact angle of the sample increased from about 107° to 130°, the filtration efficiency of PM2.5 increased from 44.778% to 98.905%, and the filtration efficiency of PM7.25 increased from 66.655% to 100% due to the electrospun PTFE nanofiber layer. This work demonstrates the potential of CPFMs as a filter for the production of indoor or outdoor dust removal and industrially relevant gas filtration.
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Lu, Yang, Jianxin Deng, Wenlong Song, Xuemu Li, Liangliang Zhang, and Jie Sun. "Tribological performance of AlCrN–MoS2/PTFE hard-lubricant composite coatings." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 234, no. 9 (2019): 1355–67. http://dx.doi.org/10.1177/1350650119878564.
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In order to improve the tribological performance of the physical vapor-deposited AlCrN coatings, molybdenum disulfide (MoS2)/poly tetra fluoroethylene (PTFE) coatings were fabricated on the AlCrN coatings surface through the thermal spraying method. The microstructure, adhesive strength, hardness, and tribological properties were investigated. Reciprocating sliding tests against SiC ball were executed with a ball-on-plate tribometer. Results showed that the adhesive strength between the AlCrN–MoS2/PTFE composite coatings and substrate was increased by about 15% compared with single AlCrN coatings. Compared with the single MoS2/PTFE coatings, the hardness of the AlCrN–MoS2/PTFE composite coatings surface was increased by about 15%. The MoS2/PTFE layer can availably reduce the friction coefficient of single AlCrN layer, and the AlCrN–MoS2/PTFE composite coatings exhibited the lowest and the most stable friction coefficient. In addition, the MoS2/PTFE layer existed on the wear track and accumulated on both the sides, which was the main reason that the friction coefficient was still lower compared with the samples without MoS2/PTFE coatings.
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Luo, Yan, Zhongyun Shen, Zhihao Ma, et al. "A Cleanable Self-Assembled Nano-SiO2/(PTFE/PEI)n/PPS Composite Filter Medium for High-Efficiency Fine Particulate Filtration." Materials 14, no. 24 (2021): 7853. http://dx.doi.org/10.3390/ma14247853.
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A silicon dioxide/polytetrafluoroethylene/polyethyleneimine/polyphenylene sulfide (SiO2/PTFE/PEI/PPS) composite filter medium with three-dimensional network structures was fabricated by using PPS nonwoven as the substrate which was widely employed as a cleanable filter medium. The PTFE/PEI bilayers were firstly coated on the surfaces of the PPS fibers through the layer-by-layer self-assembly technique ten times, followed by the deposition of SiO2 nanoparticles, yielding the SiO2/(PTFE/PEI)10/PPS composite material. The contents of the PTFE component were easily controlled by adjusting the number of self-assembled PTFE/PEI bilayers. As compared with the pure PPS nonwoven, the obtained SiO2/(PTFE/PEI)10/PPS composite material exhibits better mechanical properties and enhanced wear, oxidation and heat resistance. When employed as a filter material, the SiO2/(PTFE/PEI)10/PPS composite filter medium exhibited excellent filtration performance for fine particulate. The PM2.5 (particulate matter less than 2.5 μm) filtration efficiency reached up to 99.55%. The superior filtration efficiency possessed by the SiO2/(PTFE/PEI)10/PPS composite filter medium was due to the uniformly modified PTFE layers, which played a dual role in fine particulate filtration. On the one hand, the PTFE layers not only increase the specific surface area and pore volume of the composite filter material but also narrow the spaces between the fibers, which were conducive to forming the dust cake quickly, resulting in intercepting the fine particles more efficiently than the pure PPS filter medium. On the other hand, the PTFE layers have low surface energy, which is in favor of the detachment of dust cake during pulse-jet cleaning, showing superior reusability. Thanks to the three-dimensional network structures of the SiO2/(PTFE/PEI)10/PPS composite filter medium, the pressure drop during filtration was low.
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Łosiewicz, B., and Magdalena Popczyk. "Electrodeposition Process of Composite Ni-P+Ni(OH)2+PTFE Coatings." Solid State Phenomena 228 (March 2015): 108–15. http://dx.doi.org/10.4028/www.scientific.net/ssp.228.108.
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Co-deposition process of amorphous nickel and PTFE particles in the presence of Ni (OH)2carrier suspended in the bath by magnetic stirring, was investigated. Composite Ni-P+Ni (OH)2+PTFE coatings and comparative Ni-P deposits, were electrodeposited on low carbon steel substrate under galvanostatic conditions at room temperature. The physical and chemical characterization of the coatings was carried out using X-Ray diffraction analysis and microanalysis, stereometric quantitative microscopy and atomic absorption spectroscopy. The optimum production conditions of the composite coatings based on the Ni-P matrix into which PTFE and Ni (OH)2components can be embedded uniformly, were found.
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Rajesh, Surendran, Kodakkattu Purushothaman Murali, Kunnathodi Vijayaraghavan Rajani, and Ravendran Ratheesh. "SrTiO3-Filled PTFE Composite Laminates for Microwave Substrate Applications." International Journal of Applied Ceramic Technology 6, no. 5 (2009): 553–61. http://dx.doi.org/10.1111/j.1744-7402.2009.02389.x.
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Ying, Lixia, Yunlong Wu, Chongyang Nie, Chunxi Wu, and Guixiang Wang. "Improvement of the Tribological Properties and Corrosion Resistance of Epoxy–PTFE Composite Coating by Nanoparticle Modification." Coatings 11, no. 1 (2020): 10. http://dx.doi.org/10.3390/coatings11010010.
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In order to meet the requirements of high corrosion resistance, wear resistance, and self-lubrication of composite coatings for marine applications, epoxy matrix composite coatings containing PTFE and TiO2 nanoparticles were prepared on the steel substrate. With silane coupling agent KH570 (CH2=C(CH3)COOC3H6Si(OCH3)3), titanium dioxide nanoparticles were modified, and organic functional groups were grafted on their surface to improve their dispersion and interface compatibility in the epoxy matrix. Then, the section morphology, tribological, and anticorrosion properties of prepared coatings, including pure epoxy, epoxy–PTFE, and the composite coating with unmodified and modified TiO2, respectively, were fully characterized by scanning electron microscopy, friction–abrasion testing machine, and an electrochemical workstation. The analytical results show that the modified TiO2 nanoparticles are able to improve the epoxy–PTFE composite coating’s mechanical properties of epoxy–PTFE composite coating including section toughness, hardness, and binding force. With the synergistic action of the friction reduction of PTFE and dispersion enhancement of TiO2 nanoparticles, the dry friction coefficient decreases by more than 73%. Simultaneously, modified titanium dioxide will not have much influence on the water contact angles of the coating. A larger water contact angle and uniform and compact microstructure make the composite coating incorporated modified TiO2 nanoparticles show excellent anti-corrosion ability, which has the minimum corrosion current density of 1.688 × 10−7 A·cm−2.
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Mei, Shunqi, Cong Zhou, Zekui Hu, Zhi Xiao, Quan Zheng, and Xuhui Chai. "Preparation of a Ni-P-nanoPTFE Composite Coating on the Surface of GCr15 Steel for Spinning Rings via a Defoamer and Transition Layer and Its Wear and Corrosion Resistance." Materials 16, no. 12 (2023): 4427. http://dx.doi.org/10.3390/ma16124427.
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In this study, a method of preparing a Ni-P-nanoPTFE composite coating on the surface of GCr15 steel for spinning rings is proposed. The method incorporates a defoamer into the plating solution to inhibit the agglomeration of nano-PTFE particles and pre-deposits a Ni-P transition layer to reduce the possibility of leakage coating. Meanwhile, the effect of varying the PTFE emulsion content in the bath on the micromorphology, hardness, deposition rate, crystal structure, and PTFE content of the composite coatings was investigated. The wear and corrosion resistances of the GCr15 substrate, Ni-P coating, and Ni-P-nanoPTFE composite coating are compared. The results show that the composite coating prepared at a PTFE emulsion concentration of 8 mL/L has the highest concentration of PTFE particles (up to 2.16 wt%). Additionally, its wear resistance and corrosion resistance are improved compared with Ni-P coating. The friction and wear study shows that the nano-PTFE particles with low dynamic friction coefficient are mixed in the grinding chip, which gives the composite coating self-lubricating characteristics, and the friction coefficient decreases to 0.3 compared with 0.4 of Ni-P coating. The corrosion study shows that the corrosion potential of the composite coating has increased by 7.6% compared with that of the Ni-P coating, which shifts from −456 mV to a more positive value of −421 mV. The corrosion current reduces from 6.71 μA to 1.54 μA, which is a 77% reduction. Meanwhile, the impedance increased from 5504 Ω·cm2 to 36,440 Ω·cm2, which is an increase of 562%.
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Mi, Baoli, Qingya Meng, Junping Duan, et al. "Ultra-Broadband Wearable Antenna with Thermal Sensitivity Based on Surface-Modified TiO2-PTFE-PDMS Nanocomposites." Micromachines 16, no. 6 (2025): 629. https://doi.org/10.3390/mi16060629.
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In this study, a composite substrate with adjustable dielectric properties was prepared, and its promising application in wearable medical device antennas was demonstrated. 3-Methacryloxypropyltrimethoxysilane (KH570) was used to modify titanium dioxide (TiO2) nano-powder, and the modified powder was blended with a mixture of polydimethylsiloxane (PDMS) and polytetrafluoroethylene (PTFE) under the action of anhydrous ethanol. The resulting polymer material had the advantages of hydrophobicity, softness, low loss, and a high dielectric constant. Meanwhile, the effects of the KH570 mass fraction on the microstructure and dielectric properties of TiO2-PTFE-PDMS composites were investigated, and the results showed that when the mass fraction was 5%, the composites exhibited better dielectric properties in the range of 2–12 GHz. Finally, an ultra-wideband antenna with an operating frequency band in the range of 2.37–11.66 GHz was prepared based on this composite substrate. The antenna demonstrated significant potential for future applications in detecting environmental thermal changes due to its special temperature-sensitive linear frequency shift characteristics, and its effect on the human body under bending conditions was studied. In addition, specific absorption rate (SAR) measurements were performed to assess the effects of antenna radiation on the human body in practical applications.
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Wang, Fangfang, Jihao Ci, and Jiang Fan. "Properties and Fabrication of Waterborne Polyurethane Superhydrophobic Conductive Composites with Coupling Agent-Modified Fillers." Polymers 14, no. 15 (2022): 3093. http://dx.doi.org/10.3390/polym14153093.
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The addition of abundant fillers to obtain conductive and superhydrophobic waterborne polyurethane (WPU) composites generally results in increased interfaces in the composites, leading to reduced adhesion and poor corrosion resistance. Fillers such as Polytetrafluoroethylene (PTFE) and multi-walled carbon nanotubes (MWCNTs) were first treated by a coupling agent to reduce the contents of the fillers. Thus, in this work, WPU superhydrophobic conductive composites were prepared using electrostatic spraying (EsS). The polar groups (-OH and -COOH, etc.) on the WPU, PTFE, and MWCNTs were reacted with the coupling agent, making the WPU, PTFE, and MWCNTs become crosslinked together. Thus, the uniformity of the coating was improved and its curing interfaces were reduced, causing enhanced corrosion resistance. The dehydration reaction that occurred between the silane coupling agent and the polar surface of Fe formed -NH2 groups, increasing the adhesion of the coating to the steel substrate and then solving the problems of low adhesion, easy delamination, and exfoliation. With the increased content of the modified fillers, the conductivity and hydrophobic property of the composite were amplified, and its corrosion resistance and adhesion were first strengthened and then declined. The composite with the WPU, PTFE, MWCNTs, and KH-550 at a mass ratio of 7:1.5:0.1:0.032 held excellent properties; its volume resistivity and WCA were 1.5 × 104 Ω·cm and 155°, respectively. Compared with the pure WPU coating, its adhesive and anticorrosive properties were both better. This provides a foundation for the fabrication and application of anticorrosive and conductive waterborne composites.
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Liao, Mingjia, Yun Zhu, Genghao Gong, and Lei Qiao. "Thin-Film Composite Membranes with a Carbon Nanotube Interlayer for Organic Solvent Nanofiltration." Membranes 12, no. 8 (2022): 817. http://dx.doi.org/10.3390/membranes12080817.
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Compared to the traditional chemical-crosslinking-based polymer, the porous polytetrafluoroethylene (PTFE) substrate is considered to be an excellent support for the fabrication of thin-film composite (TFC) organic solvent nanofiltration (OSN) membranes. However, the low surface energy and chemical inertness of PTFE membranes presented major challenges for fabricating a polyamide active layer on its surface via interfacial polymerization (IP). In this study, a triple-layered TFC OSN membrane was fabricated via IP, which consisted of a PA top layer on a carbon nanotube (CNT) interlayer covering the macroporous PTFE substrate. The defect-free formation and cross-linking degree of the PA layer can be improved by controlling the CNT deposition amount to achieve a good OSN performance. This new TFC OSN membrane exhibited a high dye rejection (the rejection of Bright blue B > 97%) and a moderate and stable methanol permeated flux of approximately 8.0 L m−2 h−1 bar−1. Moreover, this TFC OSN membrane also exhibited an excellent solvent resistance to various organic solvents and long-term stability during a continuous OSN process.
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Vicente, Adrián, Pedro J. Rivero, Unai Urdiroz та ін. "Novel Design of Superhydrophobic and Anticorrosive PTFE and PAA + β − CD Composite Coating Deposited by Electrospinning, Spin Coating and Electrospraying Techniques". Polymers 14, № 20 (2022): 4356. http://dx.doi.org/10.3390/polym14204356.
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A superhydrophobic composite coating consisting of polytetrafluoroethylene (PTFE) and poly(acrylic acid)+ β-cyclodextrin (PAA + β-CD) was prepared on an aluminum alloy AA 6061T6 substrate by a three-step process of electrospinnig, spin coating, and electrospraying. The electrospinning technique is used for the fabrication of a polymeric binder layer synthesized from PAA + β-CD. The superhydrophilic characteristic of the electrospun PAA + β-CD layer makes it suitable for the absorption of an aqueous suspension with PTFE particles in a spin-coating process, obtaining a hydrophobic behavior. Then, the electrospraying of a modified PTFE dispersion forms a layer of distributed PTFE particles, in which a strong bonding of the particles with each other and with the PTFE particles fixed in the PAA + β-CD fiber matrix results in a remarkable improvement of the particles adhesion to the substrate by different heat treatments. The experimental results corroborate the important role of obtaining hierarchical micro/nano multilevel structures for the optimization of superhydrophobic surfaces, leading to water contact angles above 170°, very low contact angle of hysteresis (CAH = 2°) and roll-off angle (< 5°). In addition, a superior corrosion resistance is obtained, generating a barrier to retain the electrolyte infiltration. This study may provide useful insights for a wide range of applications.
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Alhaji, Ibrahim Abubakar, Zulkifly Abbas, Mohd Hafiz Mohd Zaid, and Ahmad Mamoun Khamis. "Effects of Particle Size on the Dielectric, Mechanical, and Thermal Properties of Recycled Borosilicate Glass-Filled PTFE Microwave Substrates." Polymers 13, no. 15 (2021): 2449. http://dx.doi.org/10.3390/polym13152449.
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Low dielectric loss and low-cost recycled borosilicate (BRS) glass-reinforced polytetrafluoroethylene (PTFE) composites were fabricated for microwave substrate applications. The composites were prepared through a dry powder processing technique by dispersing different micron sizes (25 µm, 45 µm, 63 µm, 90 µm, and 106 µm) of the recycled BRS filler in the PTFE matrix. The effect of the filler sizes on the composites’ thermal, mechanical, and dielectric properties was studied. The dielectric properties of the composites were characterised in the frequency range of 1–12 GHz using an open-ended coaxial probe (OCP) connected to a vector network analyser (VNA). XRD patterns confirmed the phase formation of PTFE and recycled BRS glass. The scanning electron microscope also showed good filler dispersion at larger filler particle sizes. In addition, the composites’ coefficient of thermal expansion and tensile strength decreased from 12.93 MPa and 64.86 ppm/°C to 7.12 MPa and 55.77 ppm/°C when the filler size is reduced from 106 μm to 25 μm. However, moisture absorption and density of the composites increased from 0.01% and 2.17 g/cm3 to 0.04% and 2.21 g/cm3. The decrement in filler size from 106 μm to 25 μm also increased the mean dielectric constant and loss tangent of the composites from 2.07 and 0.0010 to 2.18 and 0.0011, respectively, while it reduced the mean signal transmission speed from 2.088 × 108 m/s to 2.031 × 108 m/s. The presented results showed that PTFE/recycled BRS composite exhibited comparable characteristics with commercial high-frequency laminates.
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Su, Xinyao, Yonghai Gao, Faling Yin, and Shaoqiang Li. "Investigation on the Influence of Different Coating Surfaces on the Adhesive Force of Hydrate Particles." Journal of Marine Science and Engineering 12, no. 2 (2024): 232. http://dx.doi.org/10.3390/jmse12020232.
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In the process of oil and gas extraction and transportation, the aggregation and deposition of hydrate particles within oil and gas pipelines is a primary cause of pipeline blockage, with adhesion being the fundamental cause of hydrate particle aggregation. With the development of crude oil and natural gas transportation technology, the application of pipeline internal coating technology is becoming increasingly widespread. It is essential to compare the physical properties and practicality of various coating materials and conduct preliminary screening. Adhesion experiments on coating materials suitable for the conditions of oil and gas pipeline transport have been conducted. The experimental results indicate that the PTFE/PPS composite coating has advantages in reducing the adhesive force of hydrate particles under low temperatures and different degrees of subcooling. As the degree of subcooling increases, the adhesive force between the hydrate particles and the PTFE/PPS composite coating substrate gradually increases from 8.36 mN·m−1 to 10.26 mN·m−1. With a 3 °C increase in subcooling, the adhesion force increases by 1.92 mN·m−1, which is about 68% lower on average compared to an uncoated substrate. Epoxy resin E-51 coatings and polyurea coatings also demonstrate certain anti-hydrate adhesion properties, but their performance is slightly inferior compared to the PTFE/PPS composite coating. These research results can provide an important reference for hydrate prevention technology in oil and gas transportation pipelines.
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Alhaji, Ibrahim Abubakar, Zulkifly Abbas, and Aliyu Sisa Aminu. "Experimental and Simulated Investigation of S-parameters and Power Loss Characteristics of PTFE/Glass Composites at X-band Frequency." Malaysian Journal on Composites Science and Manufacturing 15, no. 1 (2024): 1–12. http://dx.doi.org/10.37934/mjcsm.15.1.112.
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Polytetrafluoroethylene (PTFE)-based substrates are in high demand for high-frequency (microwave) applications because of their low relative permittivity, enabling efficient signal transfer. In this work, PTFE composites have been prepared with different content (5 wt.% - 25 wt.%) of soda lime silica glass (SLSG) for substrate application. The composites were characterized by their complex permittivity and S-parameters through the rectangular waveguide (RWG) measurement method over x-band frequency (8.2 GHz – 12.4 GHz). The RWG set-up was connected to a vector network analyser for the characterization. Power loss of the composites due to material absorption was calculated using the measured S-parameters. As the content of the SLSG increased from 5 - 25 wt.%, complex permittivity rose from 2.18-j0.0035 to 2.56-j0.0047 in the frequency range considered. In addition, |S11| reduced from 0.623 and 0.700 to 0.418 and 0.441, whereas |S21| varied from 0.780 and 0.713 to 0.906 and 0.895 for 5 wt.% and 25 wt.% SLSG contents at 8.2 GHz and 12.4 GHz, respectively. The calculated power loss increased from 2.94 dB to 3.29 dB and 4.01 dB to 4.88 dB for the same filler contents and frequency. Furthermore, the S-parameters were simulated using the finite element method (FEM) via COMSOL software and compared with the measured values. The comparison revealed a mean relative error of < 0.1, denoting the accuracy of the RWG method. Also, the electric field distribution across the waveguide length was visualized. Thus, the optimal performance of the composite was found at 5 wt.% SLSG filler content for microwave substrate application.
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Abidin, Noraziani Zainal, Haslaniza Hashim, Saiful Irwan Zubairi, et al. "Enhancing polytetrafluoroethylene (PTFE) coated film for food processing: Unveiling surface transformations through oxygenated plasma treatment and parameter optimization using response surface methodology." PLOS ONE 19, no. 5 (2024): e0303931. http://dx.doi.org/10.1371/journal.pone.0303931.
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Spray drying fruit juice powders poses challenges because sugars and organic acids with low molecular weight and a low glass transition temperature inherently cause stickiness. This study employed a hydrophobic polytetrafluoroethylene (PTFE) film to mimic the surface of the drying chamber wall. The Central Composite Design (CCD) using response surface methodology investigated the impact of power (X1, Watt) and the duration of oxygenated plasma treatment (X2, minutes) on substrate contact angle (°), reflecting surface hydrophobicity. To validate the approach, Morinda citrofolia (MC) juice, augmented with maltodextrins as drying agents, underwent spray drying on the improved PTFE-coated surface. The spray drying process for MC juice was performed at inlet air temperatures of 120, 140, and 160°C, along with Noni juice-to-maltodextrin solids ratios of 4.00, 1.00, and 0.25. The PTFE-coated borosilicate substrate, prepared at a radio frequency (RF) power of 90W for 15 minutes of treatment time, exhibited a porous and spongy microstructure, correlating with superior contact angle performance (171°) compared to untreated borosilicate glass. Optimization data indicated that the PTFE film attained an optimum contact angle of 146.0° with a specific combination of plasma RF operating power (X1 = 74 W) and treatment duration (X2 = 10.0 minutes). RAMAN spectroscopy indicated a structural analysis with an ID/IG ratio of 0.2, while Brunauer-Emmett-Teller (BET) surface area analysis suggested an average particle size of less than 100 nm for all coated films. The process significantly improved the powder’s hygroscopicity, resistance to caking, and moisture content of maltodextrin-MC juice. Therefore, the discovery of this modification, which applies oxygen plasma treatment to PTFE-coated substrates, effectively enhances surface hydrophobicity, contact angle, porosity, roughness, and ultimately improves the efficacy and recovery of the spray drying process.
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Wu, Yulong, Haisheng Wu, Liang Wu, et al. "Influence of Electrolyte Temperature on Morphology and Properties of Composite Anodic Film on Titanium Alloy Ti-10V-2Fe-3Al." Coatings 10, no. 11 (2020): 1109. http://dx.doi.org/10.3390/coatings10111109.
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In this study, we introduced a novel environmentally-friendly electrolyte consisting of polytetrafluoroethylene (PTFE) nanoparticles and malic acid solution to fabricate composite anodic film on Ti-10V-2Fe-3Al alloy at different electrolyte temperatures. The morphology revealed that the PTFE nanoparticles were successfully incorporated into composite anodic films and embedded preferentially in the pores and cracks. Their performances (wear, corrosion and hydrophobicity) were evaluated via electrochemical tests, ball on disc tests, and a contact angle (CA) meter. Compared to the substrate of titanium alloy Ti-10V-2Fe-3Al, the composite anodic films exhibited the low wear rates, high corrosion resistance and good hydrophobicity. However, the microstructure and morphology of the films were affected by the electrolyte temperature. As a result, their performances were changed greatly as a function of the temperature and the film fabricated at 20 °C exhibited better performances (CA = 131.95, icorr = 6.75 × 10−8 A·cm−2, friction coefficient = 0.14) than those at other electrolyte temperatures. In addition, the corresponding lubrication mechanism of the composite anodic films was discussed.
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Satulu, Veronica, Bogdana Mitu, Valentin Ion, et al. "Combining Fluorinated Polymers with Ag Nanoparticles as a Route to Enhance Optical Properties of Composite Materials." Polymers 12, no. 8 (2020): 1640. http://dx.doi.org/10.3390/polym12081640.
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Polymer-based nanocomposites have recently received considerable attention due to their unique properties, which makes them feasible for applications in optics, sensors, energy, life sciences, etc. The present work focuses on the synthesis of nanocomposites consisting of a polytetrafluorethylene-like matrix in which metallic nano-silver are embedded, by using multiple magnetron plasmas. By successively exposing the substrate to separate RF magnetrons using as combination of target materials polytetrafluorethylene (PTFE) and silver, individual control of each deposition process is insured, allowing obtaining of structures in which silver nanoparticles are entrapped in-between two PTFE layers with given thicknesses. The topographical and morphological characteristics investigated by means of Scanning Electron Microscopy and Atomic Force Microscopy techniques evidenced the very presence of Ag nanoparticles with typical dimension 7 nm. The chemical composition at various depositing steps was evaluated through X-ray Photoelectron Spectroscopy. We show that the presence of the top PTFE layer prevents silver oxidation, while its thickness allows the tailoring of optical properties, as evidenced by spectroellipsometry. The appearance of chemical bonds between silver atoms and PTFE atoms at interfaces is observed, pointing out that despite of pure physical deposition processes, a chemical interaction between the polymeric matrix and metal is promoted by plasma.
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Zhang, Yu Hui, Quan Ji, and Xue Wang. "Rf Sputtering of Composite Fluorocarbon/ZnO Films and their Basic Properties." Key Engineering Materials 373-374 (March 2008): 159–62. http://dx.doi.org/10.4028/www.scientific.net/kem.373-374.159.
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Composite fluorocarbon/ZnO films were deposited by R.F. sputtering using polytetrafluoroethylene (PTFE) and Zn target on polyethylene terephthalate (PET) substrate. Argon was used as the working gas and oxygen as reacting gas. The obtained films were characterized by AFM, UV-visible spectrophotometer, XPS and static contact angle measurements. The composite films are islands-structure composed of nanometer particles. Surface of the islands is not flat. The static contact angle of water is larger than 90°, possessing excellent hydrophobicity. The composite films exhibit multi-enhanced ultraviolet absorption due to π-π-conjugated molecular structure, surface morphology and nano-sized ZnO absorbing effect.
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Wang, Peng, Hironori Nakajima, and Tatsumi Kitahara. "Effect of Hydrophilic and Hydrophobic Composite Microporous Layer Coated Gas Diffusion Layers on PEFC Performance." ECS Meeting Abstracts MA2023-02, no. 37 (2023): 1767. http://dx.doi.org/10.1149/ma2023-02371767mtgabs.
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In order to widen the market application of the polymer electrolyte fuel cell (PEFC), the output power of the PEFC system must be increased. One of the barriers is the cell voltage loss under high current density conditions. This is mainly caused by the deteriorated reactant mass transport, which is blocked by the water flooding at the catalyst layer (CL), microporous layer (MPL), and gas diffusion layer (GDL). Modifying the MPL coated on the GDL is an accessible way to provide better water management for PEFCs to elongate the operating range of the cell, so a novel MPL-coated GDL should be developed to realize the goal. Previously, we evaluated double MPL-coated GDLs, which coated a thin hydrophilic layer on the hydrophobic MPL-coated GDL in the through-plane direction. The extra hydrophilic layer was influential in promoting the introduction of water into the small pores of the hydrophobic MPL, enhancing the ability to reduce flooding, and the oxygen transport resistance under high humidity conditions can be declined. The present study evaluates a novel composite MPL that the hydrophobic and hydrophilic pores are randomly allocated in the same layer. Excess water is expelled from the hydrophilic pores while maintaining gas transport by the hydrophobic pores. To determine the appropriate hydrophobic and hydrophilic compositions, we first evaluated the most commonly used hydrophobic polytetrafluoroethylene (PTFE) binder, and the contact angle of PTFE-MPL was 136°. Polyvinyl alcohol (PVA) was chosen as the hydrophilic binder, and the contact angle of PVA-MPL was 105°. The slurry containing PTFE, PVA, carbon black, and distilled water was mixed using a mixer and then spread on the carbon paper substrate by a bar coating machine. The temperature was heated at 350°C to sinter the MPL on the substrate. However, the sintering temperature of PVA should be lower than 150°C, so the PVA in the composite MPL was burned and led to a similar contact angle as the PTFE-MPL. Meanwhile, the performance enhancement could not be obtained compared with a PTFE-MPL-coated GDL. Oppositely, when decreasing the sintering temperature to 150C°, the PTFE-PVA composite MPL demonstrated strong hydrophilicity with a small contact angle value, and the performance was exacerbated than the PTFE-MPL. Therefore, to coordinate the lower sintering temperature of PVA, polyvinylidene difluoride (PVDF) was selected as the hydrophobic binder. The contact angle of PVDF-MPL was 143°. After the PVA was preserved, the unexpectedly strong hydrophilicity was exhibited in PVDF-PVA composite MPL, aggravating the liquid water accumulation in the MPL and without performance improvement. Finally, the Nafion ionomer with relatively weak hydrophobicity was used for the composite MPL. As a hydrophilicity complement, titanium dioxide (TiO2) particles were added to the slurry to control hydrophilicity. The contact angle of Nafion/TiO2-MPL was 113°. Similarly, the Nafion/TiO2-PVDF composite MPL indicated a contact angle of 114°, and the water permeability test proved that separate hydrophobic and hydrophilic pores were generated. The oxygen transport resistances were measured based on the limiting current density values of polarization curves to evaluate the ability of the MPL-coated GDL to reduce flooding under high humidity conditions. The active area of the MEA was 1.0 cm2, and the cell temperature was kept at 35°C. Pure hydrogen and diluted oxygen (2 vol% O2 and 98 vol% N2) gases were supplied at the anode and cathode, respectively, and the flow rates were set at 1000 cm3 min-1. The relative humidity of gases supplied to the anode and cathode was 200%RH, and the gas backpressure was set at zero. The oxygen transport resistance of the Nafion/TiO2-PVDF composite MPL-coated GDL was lower than that obtained with a commercial SGL-22BB GDL. Thus, an appropriate composite MPL-coated GDL effectively enhanced PEFC performance under high humidity conditions.
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Samsuzzaman, M., M. T. Islam, Haslina Arshad, J. S. Mandeep, and N. Misran. "Circularly Polarized S Band Dual Frequency Square Patch Antenna Using Glass Microfiber Reinforced PTFE Composite." Scientific World Journal 2014 (2014): 1–10. http://dx.doi.org/10.1155/2014/345190.
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Circularly polarized (CP) dual frequency cross-shaped slotted patch antenna on 1.575 mm thick glass microfiber reinforced polytetrafluoroethylene (PTFE) composite material substrate is designed and fabricated for satellite applications. Asymmetric cross-shaped slots are embedded in the middle of the square patch for CP radiation and four hexagonal slots are etched on the four sides of the square patch for desired dual frequency. Different substrate materials have been analysed to achieve the desired operating band. The experimental results show that the impedance bandwidth is approximately 30 MHz (2.16 GHz to 2.19 GHz) for lower band and 40 MHz (3.29 GHz to 3.33 GHz) for higher band with an average peak gain of 6.59 dBiC and 5.52 dBiC, respectively. Several optimizations are performed to obtain the values of the antenna physical parameters. Moreover, the proposed antenna possesses compactness, light weight, simplicity, low cost, and circularly polarized. It is an attractive candidate for dual band satellite antennas where lower band can be used for uplink and upper band can be used for downlink.
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Ahsan, M. R., M. T. Islam, M. Habib Ullah, W. N. L. Mahadi, and T. A. Latef. "Compact Double-P Slotted Inset-Fed Microstrip Patch Antenna on High Dielectric Substrate." Scientific World Journal 2014 (2014): 1–6. http://dx.doi.org/10.1155/2014/909854.
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This paper presents a compact sized inset-fed rectangular microstrip patch antenna embedded with double-P slots. The proposed antenna has been designed and fabricated on ceramic-PTFE composite material substrate of high dielectric constant value. The measurement results from the fabricated prototype of the antenna show −10 dB reflection coefficient bandwidths of 200 MHz and 300 MHz with center resonant frequency of 1.5 GHz and 4 GHz, respectively. The fabricated antenna has attained gains of 3.52 dBi with 81% radiation efficiency and 5.72 dBi with 87% radiation efficiency for lower band and upper band, respectively. The measured E- and H-plane radiation patterns are also presented for better understanding. Good agreement between the simulation and measurement results and consistent radiation patterns make the proposed antenna suitable for GPS and C-band applications.
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Song, Hyeon-Bee, Jong-Hyeok Park, Jin-Soo Park, and Moon-Sung Kang. "Pore-Filled Proton-Exchange Membranes with Fluorinated Moiety for Fuel Cell Application." Energies 14, no. 15 (2021): 4433. http://dx.doi.org/10.3390/en14154433.
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Proton-exchange membrane fuel cells (PEMFCs) are the heart of promising hydrogen-fueled electric vehicles, and should lower their price and further improve durability. Therefore, it is necessary to enhance the performances of the proton-exchange membrane (PEM), which is a key component of a PEMFC. In this study, novel pore-filled proton-exchange membranes (PFPEMs) were developed, in which a partially fluorinated ionomer with high cross-linking density is combined with a porous polytetrafluoroethylene (PTFE) substrate. By using a thin and tough porous PTFE substrate film, it was possible to easily fabricate a composite membrane possessing sufficient physical strength and low mass transfer resistance. Therefore, it was expected that the manufacturing method would be simple and suitable for a continuous process, thereby significantly reducing the membrane price. In addition, by using a tri-functional cross-linker, the cross-linking density was increased. The oxidation stability was greatly enhanced by introducing a fluorine moiety into the polymer backbone, and the compatibility with the perfluorinated ionomer binder was also improved. The prepared PFPEMs showed stable PEMFC performance (as maximum power density) equivalent to 72% of Nafion 212. It is noted that the conductivity of the PFPEMs corresponds to 58–63% of that of Nafion 212. Thus, it is expected that a higher fuel cell performance could be achieved when the membrane resistance is further lowered.
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Srivastava, Meenu, Bharathi Bai J. Basu, and K. S. Rajam. "Improving the Hydrophobicity of ZnO by PTFE Incorporation." Journal of Nanotechnology 2011 (2011): 1–6. http://dx.doi.org/10.1155/2011/392754.
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The objective of the present study is to obtain a zinc oxide- (ZnO-) based superhydrophobic surface in a simple and cost-effective manner. Chemical immersion deposition being simple and economical has been adopted to develop modified ZnO coating on glass substrate. Several modifications of ZnO like treatment with alkanoic acid (stearic acid) and fluoroalkylsilane to tune the surface wettability (hydrophobicity) were attempted. The effect of thermal treatment on the hydrophobic performance was also studied. It was observed that thermal treatment at 70°C for 16 hrs followed by immersion in stearic acid resulted in high water contact angle (WCA), that is, a superhydrophobic surface. Thus, a modified ZnO superhydrophobic surface involves the consumption of large amount of electrical energy and time. Hence, the alternate involved the incorporation of low surface energy fluoropolymer polytetrafluoroethylene (PTFE) in the ZnO coating. The immersion deposited ZnO-PTFE composite coating on modification with either stearic acid or fluoroalkylsilane resulted in a better superhydrophobic surface. The coatings were characterized using Scanning Electron Microscope (SEM) for the surface morphology. It was found that microstructure of the coating was influenced by the additives employed. A flower-like morphology comprising of needle-like structure arranged in a radial manner was exhibited by the superhydrophobic coating.
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Yuan, Ying, Zongting Li, Lei Cao, Bin Tang, and Shuren Zhang. "Modification of Si3N4 ceramic powders and fabrication of Si3N4/PTFE composite substrate with high thermal conductivity." Ceramics International 45, no. 13 (2019): 16569–76. http://dx.doi.org/10.1016/j.ceramint.2019.05.194.
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Slepička, Petr, Nikola Slepičková Kasálková, Dominik Fajstavr, et al. "Nanostructures on Fluoropolymer Nanotextile Prepared Using a High-Energy Excimer Laser." Materials 16, no. 12 (2023): 4280. http://dx.doi.org/10.3390/ma16124280.
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This study is focused on polytetrafluoroethylene (PTFE) porous nanotextile and its modification with thin, silver sputtered nanolayers, combined with a subsequent modification with an excimer laser. The KrF excimer laser was set to single-shot pulse mode. Subsequently, the physico chemical properties, morphology, surface chemistry, and wettability were determined. Minor effects of the excimer laser on the pristine PTFE substrate were described, but significant changes were observed after the application of the excimer laser to the polytetrafluoroethylene with sputtered silver, where the formation of a silver nanoparticles/PTFE/Ag composite was described, with a wettability similar to that of a superhydrophobic surface. Both scanning electron microscopy and atomic force microscopy revealed the formation of superposed globular structures on the polytetrafluoroethylene lamellar primary structure, which was also confirmed using energy dispersive spectroscopy. The combined changes in the surface morphology, chemistry, and thus wettability induced a significant change in the PTFE’s antibacterial properties. Samples coated with silver and further treated with the excimer laser 150 mJ/cm2 inhibited 100% of the bacterial strain E. coli. The motivation of this study was to find a material with flexible and elastic properties and a hydrophobic character, with antibacterial properties that could be enhanced with silver nanoparticles, but hydrophobic properties that would be maintained. These properties can be used in different types of applications, mainly in tissue engineering and the medicinal industry, where water-repellent materials may play important roles. This synergy was achieved via the technique we proposed, and even when the Ag nanostructures were prepared, the high hydrophobicity of the system Ag-polytetrafluorethylene was maintained.
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David, Vatamanu, and Miclaus Simona. "An analysis of the Influence of the Dielectric Substrate Parameters on the Performances of Koch and Minkowski Single-Iteration Fractal Antennas." European Journal of Advances in Engineering and Technology 7, no. 8 (2020): 1–8. https://doi.org/10.5281/zenodo.10667343.
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<strong>ABSTRACT</strong> Two simple printed fractal antennas were simulated in FEKO software with the aim of observing the influence of the dielectric substrate on their total efficiency and radiation patterns. The computations were made in the frequency range (0.5-3) GHz which is of interest for various wireless communication applications. Three types of dielectrics were investigated: an affordable material, the glass-reinforced FR-4 and two high-performance composite laminates made of Poly Tetra Fluoro Ethylene filled with glass or ceramic –duroid RT5880 and RO3003. Analyses on the obtained performances took into account: a) the nature of the dielectric substrate; b) its thickness; c) its area; d) the presence of other conductive material on the substrate. For example, RO3003 at 10 mm thick provided a maximum total efficiency of 88% of the Koch-1 antenna at a maximum realized gain of 6dBi. A usable bandwidth of 320 MHz could be achieved with this configuration while conditioning that total efficiency to always exceed 45%.
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Zhang, Rui, Jingwen Liu, Yangyang Wang, Zhongbao Luo, Binzhen Zhang, and Junping Duan. "Flexible Wearable Composite Antennas for Global Wireless Communication Systems." Sensors 21, no. 18 (2021): 6083. http://dx.doi.org/10.3390/s21186083.
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Although wearable antennas have made great progress in recent years, how to design high-performance antennas suitable for most wireless communication systems has always been the direction of RF workers. In this paper, a new approach for the design and manufacture of a compact, low-profile, broadband, omni-directional and conformal antenna is presented, including the use of a customized flexible dielectric substrate with high permittivity and low loss tangent to realize the compact sensing antenna. Poly-di-methyl-siloxane (PDMS) is doped a certain proportion of aluminum trioxide (Al2O3) and Poly-tetra-fluoro-ethylene (PTFE) to investigate the effect of dielectric constant and loss tangent. Through a large number of comparative experiments, data on different doping ratios show that the new doped materials are flexible enough to increase dielectric constant, reduce loss tangent and significantly improve the load resistance capacity. The antenna is configured with a multisection microstrip stepped impedance resonator structure (SIR) to expand the bandwidth. The measured reflection return loss (S11) showed an operating frequency band from 0.99 to 9.41 GHz, with a band ratio of 146%. The antenna covers two important frequency bands, 1.71–2.484 GHz (personal communication system and wireless body area network (WBAN) systems) and 5.15–5.825 GHz (wireless local area network-WLAN)]. It also passed the SAR test for human safety. Therefore, the proposed antenna offers a good chance for full coverage of WLAN and large-scale development of wearable products. It also has potential applications in communication systems, wireless energy acquisition systems and other wireless systems.
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Washington, Brian, Gabriel Goenaga, and Thomas A. Zawodzinski. "(Digital Presentation) Evaluating the Performance of Multi-Walled Carbon Nanotube Composite Microporous Layers Deposited on Carbon Felt Gas Diffusion Layers." ECS Meeting Abstracts MA2022-02, no. 1 (2022): 15. http://dx.doi.org/10.1149/ma2022-02115mtgabs.
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Electrochemical energy storage devices (EESDs) such as metal-air batteries (MABs) and alkaline electrolyte membrane fuel cells (AEMFCs) have begun to gain vast amounts of attention due to their high theoretical energy densities and open-circuit voltage values. Although these devices present promising aspects for the environment and sustainability, they suffer from the slow reaction kinetics and degradation effects that occur at the catalyst layer interface of the air electrode. Typically, these effects are due to the accumulation of molecular species such as water or oxygen at catalyst active sites because of poor electrode hydrophobicity and fluid management. Herein, we perform experimentation to mitigate these effects by implementing mixed carbon composite microporous layers onto porous carbon felt based air electrodes. This adaptation of the air cathode was predominantly based on the aforementioned downfalls and the lack of availability of commercial carbon felts that have adequate wet proofing and conductivity like some of the related carbon paper gas diffusion layers. Microporous layers (MPLs) enhance electrical conductivity, surface area, and adhesion at the catalyst layer and gas diffusion layer interface. These layers typically consist of a hydrophobic polymer such as polytetrafluoroethylene (PTFE) and a conductive carbon black substrate such as Ketjen Black 600JD (KJB). The incorporation of multi-walled carbon nanotube (MWCNT) and carbon black composites into the structure of the MPLs drastically decreases ohmic polarization with minimal increases in specific resistance. The electrical resistance of the synthesized carbon substrate decreases at high rates of MWCNT dispersion, which corresponds directly to a low MWCNT weight percentage within the composite. The MPL increases the mass transport through the electrode by mitigating flooding effects that typically occur within the pores near the surface of the catalyst layer, ultimately aiding in charge transfer between the gas diffusion layer and catalyst active sites. Preliminary data from AEMFC symmetric cell tests suggests that a microporous layer consisting of a 10 wt.% MWCNT/KJB (m/m) substrate is the optimal loading of carbon nanotubes and leads to better cell performance. There is an increase in current density of 60 mA/cm2 compared to an air electrode with no MPL within the ohmic region of the polarization curve corresponding to approximately 0.7 V, while only an increase of 18 mA/cm2 is seen for an MPL consisting of a 30 wt.% MWCNT/KJB (m/m) carbon substrate. The increase of charge transfer by the 10 wt.% synthesized carbon substrate MPL was attributed to the ability of the nanotubes at high rates of dispersion to act as molecular wires within the electrode. Additionally, zinc-air battery tests using the optimally configured air electrode, determined from previous experiments, show that the current density at an operating voltage of 1.1 V was increased by 2.3 times that of an electrode without an MPL using the same catalyst material and loading. Significantly, this research will lead to a better understanding of optimization of the air electrode used within electrochemical devices and how to eliminate some of the adverse effects associated with it. Figure 1
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Hwang, Insung. "PTFE-Based Solvent-Free Electrode Manufacturing Process for Lithium-Ion Batteries and Solid-State Batteries." ECS Meeting Abstracts MA2024-02, no. 5 (2024): 619. https://doi.org/10.1149/ma2024-025619mtgabs.
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As the global energy and climate crisis continues to escalate, the importance of secondary batteries is continuously growing. The current generation's lithium-ion battery technology has received widespread attention from various sectors worldwide, experiencing explosive growth. However, it seems to be entering a saturation phase in terms of technological advancement. Most research has primarily focused on material-centric approaches, such as High-Ni cathode materials and Si-based anode materials, to improve battery energy density. Research on electrode manufacturing processes has been relatively lacking. However, in recent years, dry electrode manufacturing processes have gained significant attention, owing to the distinct features and advantages over conventional slurry-based electrode processes. Firstly, thick electrode formation is required to enhance battery energy density. In conventional slurry processes, difficulties arise in manufacturing thick electrodes due to binder and conductive material migration issues, leading to decreased electrode performance. In contrast, dry processes eliminate the solvent drying stage, avoiding the aforementioned issues and enabling easier manufacturing of high-performance thick electrodes, thus effectively improving battery energy density. Additionally, dry processes offer advantages in terms of cost and environmental impact. Slurry processes require substantial energy input for solvent drying, necessitating large-scale equipment and incurring high costs. Moreover, harmful NMP vapor emissions during electrode drying require additional expenses for solvent recovery systems. In contrast, dry processes eliminate the need for solvent drying, offering environmental and cost advantages and often being labeled as low-carbon environmentally friendly processes. There are various types of 'dry electrode manufacturing processes' because absence of any solvent is the only requirement to be considered as a dry process. Among them, currently, the most commercially viable dry manufacturing technology utilizes PTFE fibrillation, initially patented by Maxwell in the United States and extensively promoted by Tesla. This technique involves mixing and kneading active materials, conductive additives, and PTFE without solvents, shaping them into film form. Notably, the resulting electrode layer exists as a free-standing film, distinct from being directly coated on a substrate. This presentation will introduce the manufacturing technology of lithium secondary battery thick electrodes using PTFE fibrillation-based dry processes, as well as the manufacturing technology of cathodes for all-solid-state batteries(ASSBs). For the dry manufacturing process of thick electrodes of lithium ion batteries, key factors needed to be deeply explored will be introduced, based on every process stage. Along with an overview of materials, equipment, and processes, basic research results on the mechanical and electrochemical properties of dry thick electrodes manufactured through dry processes will be shared. Furthermore, research results on the application of dry manufacturing processes to sulfide-based solid-state batteries, which is considered as a promising application area, will be introduced. Due to its excellent ionic conductivity and superior ductility, sulfide-based solid electrolytes like LPSCl are considered the most promising solid electrolyte for ASSBs. However, they are too much vulnerable to polar solvents, which poses a challenge when using slurry-based electrode manufacturing processes. To overcome this issue, research has been conducted on the development of composite cathodes based on sulfide-based solid electrolytes using solvent-free dry manufacturing processes, especially PTFE-based process, achieving scale-up possibility of manufacturing processes. The manufacturing of large-area solid-state battery cathode free-standing films with widths exceeding 200mm and theoretically infinite lengths was possible, exhibiting enough mechanical strength and flexibility for roll-to-roll processes. In pouch cell systems, composed of dry-manufactured composite cathode, LPSCl membrane, and Ag/C anode, initial discharge capacity of up to 200 mAh/g was achieved, demonstrating the potential for commercialization of sulfide-based all-solid-state batteries.
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Zhou, Dianbing, Yuanyuan Wang, Yingjie Ren, et al. "Coupling agent modified MGSA ceramic powder filled PTFE composite materials: High thermal conductivity and low dielectric loss of substrate materials for microwave high frequency and high-speed communication." Journal of Alloys and Compounds 1012 (January 2025): 178577. https://doi.org/10.1016/j.jallcom.2025.178577.
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Ramlan, Nadiah, Saiful Irwan Zubairi, and Mohamad Yusof Maskat. "Response Surface Optimisation of Polydimethylsiloxane (PDMS) on Borosilicate Glass and Stainless Steel (SS316) to Increase Hydrophobicity." Molecules 27, no. 11 (2022): 3388. http://dx.doi.org/10.3390/molecules27113388.
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Particle deposition on the surface of a drying chamber is the main drawback in the spray drying process, reducing product recovery and affecting the quality of the product. In view of this, the potential application of chemical surface modification to produce a hydrophobic surface that reduces the powder adhesion (biofouling) on the wall of the drying chamber is investigated in this study. A hydrophobic polydimethylsiloxane (PDMS) solution was used in the vertical dipping method at room temperature to determine the optimum coating parameters on borosilicate glass and stainless steel substrates, which were used to mimic the wall surface of the drying chamber, to achieve highly hydrophobic surfaces. A single-factor experiment was used to define the range of the PDMS concentration and treatment duration using the Response Surface Methodology (RSM). The Central Composite Rotatable Design (CCRD) was used to study the effects of the concentration of the PDMS solution (X1, %) and the treatment duration (X2, h) on the contact angle of the substrates (°), which reflected the hydrophobicity of the surface. A three-dimensional response surface was constructed to examine the influence of the PDMS concentration and treatment duration on contact angle readings, which serve as an indicator of the surface’s hydrophobic characteristics. Based on the optimisation study, the PDMS coating for the borosilicate glass achieved an optimum contact angle of 99.33° through the combination of a PDMS concentration of X1 = 1% (w/v) and treatment time of X2 = 4.94 h, while the PDMS coating for the stainless steel substrate achieved an optimum contact angle of 98.31° with a PDMS concentration of X1 = 1% (w/v) and treatment time of X2 = 1 h. Additionally, the infrared spectra identified several new peaks that appeared on the PDMS-treated surfaces, which represented the presence of Si-O-Si, Si-CH3, CH2, and CH3 functional groups for the substrates coated with PDMS. Furthermore, the surface morphology analysis using the Field Emission Scanning Electron Microscopy (FESEM) showed the presence of significant roughness and a uniform nanostructure on the surface of the PDMS-treated substrates, which indicates the reduction in wettability and the potential effect of unwanted biofouling on the spray drying chamber. The application of PDMS and PTFE on the optimally coated substrates successfully reduced the amount of full cream milk particles that adhered to the surface. The low surface energy of the treated surface (19–27 mJ/m2) and the slightly higher surface tension of the full cream milk (54–59 mJ/m2) resulted in a high contact angle (102–103°) and reduced the adhesion work on the treated substrates (41–46 mJ/m2) as compared to the native substrates.
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Sun, Rui Min, Hui Zhao, and Yong Heng Zhou. "Preparation of PAI Composite Coatings and its Tribological Behaviors." Advanced Materials Research 941-944 (June 2014): 1612–15. http://dx.doi.org/10.4028/www.scientific.net/amr.941-944.1612.
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PAI/SiC-and PAI/SiC/PTFE-composite coatings were prepared, which were deposited on Al substrates using spraying technology to improve their surfaces performance. Friction and wear of PAI composite coatings were evaluated on a ball-on-block wear tester, and thermal properties were investigated by TG. It is found that, the friction coefficient and wear rate of PAI coatings reaches the best value when the content of SiC and PTFE is 10 wt % and 0.8wt% respectively, and the friction coefficient of the composites coatings decrease but the wear rate increase with increasing applied load; TG curves shows that the PAI composite coatings have excellent heat resistance. Furthermore, the surface of PAI coatings is perfect without bubbling, desquamating and cracking when it is heated for 2 hour at 250◦C in turn three cycles.
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Yuan, Y., S. R. Zhang, X. H. Zhou, and E. Z. Li. "MgTiO3 filled PTFE composites for microwave substrate applications." Materials Chemistry and Physics 141, no. 1 (2013): 175–79. http://dx.doi.org/10.1016/j.matchemphys.2013.04.043.
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Rajesh, S., K. P. Murali, V. Priyadarsini, S. N. Potty, and R. Ratheesh. "Rutile filled PTFE composites for flexible microwave substrate applications." Materials Science and Engineering: B 163, no. 1 (2009): 1–7. http://dx.doi.org/10.1016/j.mseb.2009.04.011.
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Li, Junpeng, Jixiang Li, Jianbo Xiang, et al. "Improving Tribological Performance of Poly(phenylene sulfide) by Incorporating PTFE Fillers: The Influence of Filler Type and Concentrations." Polymers 17, no. 9 (2025): 1222. https://doi.org/10.3390/polym17091222.
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Poly(phenylene sulfide) (PPS) is a high-performance thermoplastic engineering material with excellent comprehensive performance that finds application in many fields due to its good processability, excellent heat resistance, and mechanical properties. However, the poor friction and wear properties of PPS limit its wide application in industrial sectors. In this work, polytetrafluoroethylene (PTFE) was adopted as the solid tribo-modifier to improve the tribological performance of PPS. The efficacy of using three types of PTFE fillers, namely PTFE fiber, micropowder, and nanopowder, was comparatively investigated. The results revealed that the incorporation of PTFE was beneficial to improving the tribological properties of PPS and PTFE nanopowders, which were prepared by irradiation treatment technology that demonstrated the best modification effect in terms of both tribological and mechanical performance among the studied systems. In addition, the coefficient of friction and specific wear rate of PPS composites with 30 wt% nanopowders reached 0.165 and 3.59 × 10−5 mm3/Nm, respectively, which were 70.7% and 99.0% lower than their pure PPS counterparts. The above finding was attributed to the improved compatibility between the PTFE nanopowders and the PPS substrate as well as the easier formation of intact PTFE transfer film on the contact surface. This work shows some perspective for designing self-lubricating polymer composites that broaden their application in industrial sectors.
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Su, Jun, Jiaye Ye, Zhenyu Qin, and Lidong Sun. "Polytetrafluoroethylene Modified Nafion Membranes by Magnetron Sputtering for Vanadium Redox Flow Batteries." Coatings 12, no. 3 (2022): 378. http://dx.doi.org/10.3390/coatings12030378.
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Commercial Nafion membranes have been widely used for vanadium redox flow batteries (VRFB) but with relatively low ion selectivity. A chemical method is commonly employed to modify the organic membranes, whereas physical approaches are rarely reported in view of less compatibility with the organic species. In this study, an ultrathin polytetrafluoroethylene (PTFE) film of less than 30 nm is deposited onto the Nafion substrates by radio frequency magnetron sputtering to form PTFE@Nafion composite membranes. The PTFE layer of hydrophobic and inert feature enhances the dimensional stability and the ion selectivity of the Nafion membranes. The VRFB single cell with an optimized composite membrane exhibits a better self-discharge property than that of the Nafion 212 (i.e., 201.2 vs. 18.6 h), due to a higher ion selectivity (i.e., 21.191 × 104 vs. 11.054 × 104 S min cm–3). The composite membranes also show better discharge capacity retention than the Nafion 212 over the entire 100 cycles. The results indicate that the magnetron sputtering is an alternative and feasible route to tailor the organic membranes via surface modification and functionalization.
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Choi, Hong Je, Myung Pyo Chun, Yong Soo Cho, and Hak Rae Cho. "Dielectric Characteristics of Polytetrafluoroethylene-based Composites for Microwave Substrates with Formation Pressure." Journal of the Korean Institute of Electrical and Electronic Material Engineers 26, no. 6 (2013): 429–33. http://dx.doi.org/10.4313/jkem.2013.26.6.429.
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Xi, Changqing, Bochao Zhang, Xiangdong Ye, and Honghua Yan. "Fabrication of Polytetrafluoroethylene-Reinforced Fluorocarbon Composite Coatings and Tribological Properties Under Multi-Environment Working Conditions." Polymers 16, no. 24 (2024): 3595. https://doi.org/10.3390/polym16243595.
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Currently, few studies have been conducted on the use of fluorocarbon resin (FEVE) and polytetrafluoroethylene (PTFE) as adhesive substrates and lubricating and anti-corrosion fillers, respectively, for the fabrication of PTFE-reinforced fluorocarbon composite coatings. In this paper, the tribological properties of polytetrafluoroethylene-reinforced fluorocarbon composite coatings were investigated through orthogonal tests under various operating conditions. The optimal configuration for coating preparation under dry friction and aqueous lubrication was thus obtained: the optimal filler particle size, mass ratio of FEVE to PTFE, spraying pressure, and curing agent content were 50 μm, 3:4.5, 0.3 MPa, and 0.3, respectively. Under oil lubrication, the corresponding optimal values were 5 μm, 3:4.5, 0.3 MPa, and 0.3, respectively. Tribological tests revealed that the best overall performance of the FEVE/PTFE coating was obtained when the mass ratio of FEVE to PTFE was 3:4.5, and the filler particle size also significantly affected the tribological properties under different environments, including the friction coefficients of the FEVE/50 μm-PTFE coating under both dry friction and aqueous lubrication, as well as the friction coefficient of the FEVE/5 μm-PTFE coating under oil lubrication. These coefficients were 0.067, 0.062, and 0.055, representing decreases of 86%, 92%, and 56%, respectively, compared to those of the pure FEVE coating under the same working conditions. This research was conducted with the goal of expanding the application of fluorocarbon coatings in the field of tribology.
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Vasconcelos, Beatriz, Ricardo Serra, João Oliveira, and Carlos Fonseca. "Characterization and Tribological Behavior of Electroless-Deposited Ni-P-PTFE Films on NBR Substrates for Dynamic Contact Applications." Coatings 12, no. 10 (2022): 1410. http://dx.doi.org/10.3390/coatings12101410.
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The use of rubber in dynamic contacts often results in severe degradation and wear of the rubber surface, which is why dynamic rubber seal contacts are usually oil lubricated to ensure their functionality. However, the increasing demand for more convenient and environmentally friendly sealing solutions has prompted the development of dry low-friction rubber coatings. In this work, and for the first time, Ni-P and polytetrafluoroethylene (PTFE) particles were co-deposited by electroless plating on Nitrile Butadiene Rubber (NBR), as a low-cost solution to improve the NBR tribological behavior. A cationic surfactant, cetyltrimethylammonium bromide (CTAB), was added to the plating bath to ensure a homogeneous and efficient incorporation of PTFE into the Ni-P. The optimized PTFE incorporation reached 6.8%, and the composite coating adhesion to NBR was 20% higher than that of nickel-phosphorous (Ni-P) films. The tribological properties of the coatings evaluated by pin-on-disk tests showed a marginal decrease in the coefficient of friction (CoF) (10%, 1 N load), compared to that of Ni-P. However, the tested PTFE-based coatings displayed significantly smoother surfaces with less debris and cracks, clearly demonstrating the benefits of the PTFE in terms of wear resistance for loads up to 5 N.
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Basu, Bharathibai J., and V. Dinesh Kumar. "Fabrication of Superhydrophobic Nanocomposite Coatings Using Polytetrafluoroethylene and Silica Nanoparticles." ISRN Nanotechnology 2011 (July 2, 2011): 1–6. http://dx.doi.org/10.5402/2011/803910.
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Superhydrophobic nanocomposite coatings were fabricated by incorporating hydrophobically modified silica (HMS) nanoparticles in polytetrafluoroethylene (PTFE) emulsion. Hydrophobicity of the coating was dependent on the concentration of HMS. Coatings containing optimum amounts of PTFE and HMS exhibited superhydrophobic property with high water contact angle (WCA) of 165∘ and low sliding angle <2∘. Scanning electron microscopic (SEM) studies have shown a binary surface topography composed of microbumps and nanoscale granules. The synergistic effect of the micro-nano-binary structure and low surface energy of PTFE was responsible for the superhydrophobicity of the coating. The method is simple and cost-effective and can be used for preparing self-cleaning superhydrophobic coatings on large areas of different kinds of substrates like glass, metal, and composites.
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James, Nijesh K., K. Stanly Jacob, K. P. Murali, and R. Ratheesh. "Ba(Mg1/3Ta2/3)O3 filled PTFE composites for microwave substrate applications." Materials Chemistry and Physics 122, no. 2-3 (2010): 507–11. http://dx.doi.org/10.1016/j.matchemphys.2010.03.035.
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Murali, K. P., S. Rajesh, Om Prakash, A. R. Kulkarni, and R. Ratheesh. "Comparison of alumina and magnesia filled PTFE composites for microwave substrate applications." Materials Chemistry and Physics 113, no. 1 (2009): 290–95. http://dx.doi.org/10.1016/j.matchemphys.2008.07.089.
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Huang, Fangkai, Ying Yuan, Zehua Jiang, Bin Tang, and Shuren Zhang. "Microstructures and properties of glass fiber reinforced PTFE composite substrates with laminated construction." Materials Research Express 6, no. 7 (2019): 075305. http://dx.doi.org/10.1088/2053-1591/ab11f2.
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Yu, Yuanying, Xiao Chen, Dajun Hou, et al. "Fluorinated Polydopamine Shell Decorated Fillers in Polytetrafluoroethylene Composite for Achieving Highly Reduced Coefficient of Thermal Expansion." Polymers 16, no. 7 (2024): 987. http://dx.doi.org/10.3390/polym16070987.
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The noticeable difference in the coefficient of thermal expansion (CTE) for polytetrafluoroethylene (PTFE) coatings and copper substrates is a major challenge for thermal debonding of the copper-clad laminate (CCL) in high-frequency communications. Theoretically, ceramic fillers with low CTEs in the coating can effectively reduce the gap, and there remains a trade-off between the dispersibility of fillers and the interfacial interactions with the polymeric matrix. Here, we propose a novel approach to prepare a pentafluorobenzoyl chloride (PFBC)-modified polydopamine (PDA) shell on silica particles by using amidation. Such modified particles perform excellent dispersion and exhibit diminished interfacial gaps in the PTFE matrix, which highly reduces CTE to 77 ppm/°C, accounting for only 48.1% of the neat coating. Moreover, the composite exhibits enhanced mechanical strength and toughness, and consequently suppresses thermal debonding in CCL under high-temperature conditions. Therefore, results present a promising potential for its use in the next-generation CCL of high-frequency communication devices.