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Robust conductive micropatterns on PTFE achieved via selective UV- induced graft copolymerization for flexible electronic applications
摘要： Fabrication of stable and functional patterns on the surface of polytetrafluoroethylene (PTFE) remains a great technical challenge owing to its inertness and high hydrophobicity. Here, we report for the first time the fabrication of functional micro-patterns on the PTFE surface by selectively irradiating plasma-treated PTFE coated with the monomer solution. A series of uniform, highly dense polydopamine methacrylamide (denoted as PDMA) line patterns with the line/pitch width 20μm/20μm and 50μm/50μm were fabricated on the surface of PTFE (denoted as PDMA-p/PTFE) using dopamine methacrylamide (DMA) as the monomer. The surface graft copolymerization occurs attributed to the universal adsorption of DMA and the low grafting energy barrier, comparing with the polymerization energy barrier, which is also demonstrated by the density functional theory (DFT) calculations. Further, robust, well-defined metal Ag or Cu patterns with the strong adhesion strength are fabricated on the surface the PTFE film by electroless deposition, and demonstrated for applications in flexible electronics. The approach is demonstrated to be versatile for fabrication of PDMA micropatterns onto a wide range of polymeric substrates including polypropylene (PP), and acrylonitrile butadiene styrene (ABS).
关键词： dopamine methacrylamide,UV irradiation,graft copolymerization,metal patterns,Surface grafting,PTFE
更新于2025-09-23 15:23:52
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Mechanistic reaction pathway for hexafluoropropylene oxide pulsed plasma deposition of PTFE-like films
摘要： The pulsed plasma deposition of PTFE-like thin films using hexafluoropropylene oxide (HFPO) precursor has been investigated by time-resolved in situ mass spectrometry. Electron-impact and electron-attachment ionisation modes have been employed to monitor neutral plasma species; whilst electrical discharge negative and positive ions have been detected by switching-off the mass spectrometer electron-impact ionisation source. The relative concentrations of neutral versus ionic plasma species were found to rise for shorter pulse duty cycles. Mechanistically, HFPO molecules undergo pulsed plasma-initiated decomposition to form difluorocarbene (:CF2) radical species, and these can combine to form tetrafluoroethylene (CF2=CF2) molecules, which subsequently polymerise leading to the growth of PTFE-like ([–CF2–]n) perfluoroalkyl chains. Shorter pulsed plasma duty cycles enhance the growth of linear PTFE-like perfluoroalkyl chains.
关键词： pulsed plasma,PTFE,mechanistic reaction pathway,nanofilms
更新于2025-09-23 15:23:52
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Influence of laser texturing on the wettability of PTFE
摘要： Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer showing excellent thermal and electrical insulation properties and a low coefficient of friction. Due to its large stability, and hydrophobic nature, the wettability of PTFE surfaces can be reduced to transform them into superhydrophobic. In this regard, laser texturing is a fast, simple and versatile method to produce superhydrophobic PTFE surfaces in one-step, and over large areas. In this work, we used a CO2 laser to modify the surface of PTFE samples. We studied the effect of the processing parameters (laser power or irradiance, scanning speed, and spacing -overlapping- between scan lines) on the wettability of textured surfaces using water, mineral oil and ethanol/water solutions as test fluids. Laser-treated surfaces showed a hierarchical micro- and nanotopography with a cotton-like appearance. The higher roughness and large quantity of air pockets make these laser-treated surfaces superhydrophobic, and highly oleophobic. Furthermore, they remain unaltered after being in contact with strong alkali and acid solutions or after slight friction. The self-cleaning performance of these surfaces was also demonstrated. The present findings suggest that CO2 laser texturing of PTFE is suitable for the large-scale preparation of surfaces with low-wettability to different liquids.
关键词： Polytetrafluoroethylene (PTFE),self-cleaning,wettability,laser texturing
更新于2025-09-23 15:19:57
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Study on the Main Influencing Factors in the Removal Process of Non-Stick Fluoropolymer Coatings Using Nd:YAG Laser
摘要： The coatings with fluoropolymer resins rich in fluorinated ethylene propylene (FEP) and polytetrafluoroethylene (PTFE) are applied as anti-adherent coatings on aluminum–magnesium substrates for use in food containers. In many cases, due to wear, they must be stripped for the application of a new coating on the same substrate. There are several processes for this: blasting, plasma, pyrolysis, chemical processes, laser, high pressure water, and combinations of these. This work focuses on the characterization of the main factors that condition the FEP coating removal process by a continuous wave (CW) Nd:YAG laser, and on the determination of the efficiency of this type of technology used for this purpose. Stripping surface per unit of time and energy consumption per unit area has been determined among other efficiency indicators. Regarding the characterization of the coating object of study, its thickness, surface roughness, contact angle, microhardness and absorbance-reflectance responses have been determined, and the results have been compared with those obtained in the case of PTFE. In addition, to evaluate the mechanical damage caused in the substrate after coating removal by (CW) Nd:YAG laser, the tensile strength, Vickers hardness, Ra and Rz roughness, and the substrate thickness have been measured and analyzed.
关键词： laser coating removal,PTFE coatings,FPE coatings,Nd:YAG laser,laser stripping
更新于2025-09-19 17:15:36
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Laser Welding of Carbon fibre filled Polytetrafluoroethylene
摘要： Herein, a method is described to weld polytetrafluoroethylene (PTFE), a non-melt processable thermoplast, using a thulium laser. Different settings for laser power and speed were used. The resulting mean lap shear strength per setting ranged from 0.081 N/mm2 to 0.297 N/mm2. The optimal setting was found to be 12 W irrespective of the welding speed applied. Micro-computed tomography (μ-CT) and optical microscopy was used to show that the welded pattern consisted of tunnel defects. As PTFE is known to be non-melt processable, a physico-chemical characterization was performed to examine the formation of degradation products. Differential scanning calorimetry (DSC) showed a reduction in molecular weight of the PTFE in the weld pattern after welding. Attenuated total reflectance infrared (ATR-IR) and nuclear magnetic resonance (NMR) spectroscopy using hexafluoroisopropanol (HFIP) did not indicate the presence of any new compounds in the respective spectra.
关键词： Laser transmission welding,Polytetrafluoroethylene (PTFE),Physico-chemical characterization,Degradation
更新于2025-09-19 17:13:59
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Feasibility study for rapid near-infrared spectroscopic identification of different gallbladder diseases by direct analysis of bile juice
摘要： A whole-sample-covering near-infrared (NIR) spectroscopy scheme has been adopted for the simple drop-and-dry measurement of raw bile juice for the identification of gallbladder (GB) diseases of stone, polyp, and cancer. For reproducible measurement, a non-NIR absorbing polytetrafluoroethylene (PTFE) providing a hydrophobic surface was chosen as a substrate to form bile juice droplets of a consistent shape. To ensure representative spectroscopic sampling, NIR radiation illuminated the whole area of the dried sample for spectral acquisition. The NIR band shapes and relative band intensities of GB cancer differed moderately from those of GB stone and GB polyp. The composition of GB cancer samples was presumed to be dissimilar from other sample compositions. Differentiation between GB polyp and GB stone, however, was less facile; nevertheless, in the case of GB polyp samples, the obtained NIR features were informative in the identification of various pathological conditions such as adenomyomatosis (abnormal growth of epidermal tissue) and hepatitis B. To elucidate the NIR features of bile juice samples, separate NIR spectra of major bile constituents such as conjugated bile salts, lecithin, cholesterol, and albumin were analyzed. The demonstrated NIR spectroscopy scheme requiring no sample pretreatment or separation of bile juice could be useful for fast bile juice-based screening of GB diseases, especially the identification of early GB cancer.
关键词： gallbladder diseases,bile juice,drop-and-dry measurement,PTFE substrate,near-infrared spectroscopy
更新于2025-09-12 10:27:22
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Influence of Femtosecond Laser Surface Nanotexturing on the Friction Behavior of Silicon Sliding Against PTFE
摘要： The aim of the present work was to investigate the influence of laser-induced periodic surface structures (LIPSS) produced by femtosecond laser on the friction behavior of silicon sliding on polytetrafluoroethylene (PTFE) in unlubricated conditions. Tribological tests were performed on polished and textured samples in air using a ball-on-flat nanotribometer, in order to evaluate the friction coefficient of polished and textured silicon samples, parallel and perpendicularly to the LIPSS orientation. In the polished specimens, the friction coefficient decreases with testing time at 5 mN, while it increases slightly at 25 mN. It also decreases with increasing applied load. For the textured specimens, the friction coefficient tends to decrease with testing time in both sliding directions studied. In the parallel sliding direction, the friction coefficient decreases with increasing load, attaining values similar to those measured for the polished specimen, while it is independent of the applied load in the perpendicular sliding direction, exhibiting values lower than in the two other cases. These results can be explained by variations in the main contributions to friction and in the wear mechanisms. The influence of the temperature increase at the interface and the consequent changes in the crystalline phases of PTFE are also considered.
关键词： silicon,laser surface texturing,friction,LIPSS,PTFE,laser-induced periodic surface structures
更新于2025-09-11 14:15:04
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Surface Modification of Fluoropolymer Using Open-Air Plasma Treatment at Atmospheric Pressure with Ar, Ar＋O<sub>2</sub>, and Ar＋H<sub>2</sub> for Application in HighAdhesion Metal Wiring Patterns
摘要： We performed open-air plasma treatment of polytetrafluoroethylene (PTFE) at atmospheric pressure to increase the adhesion strength between PTFE and an Ag metal film formed from Ag ink. Coloration of the PTFE surface occurred during 600 s treatment with Ar plasma. The Ag/PTFE adhesion strength was 0.06 N/mm. To resolve the problem of coloration and to improve the adhesion strength, O2 or H2 gas was added. During treatment with Ar + O2 plasma with O2 content of 0.33% for 600 s, no coloration occurred but the adhesion strength decreased to zero. During treatment with Ar + H2 plasma for 600 s, coloration did not occur. Moreover, the adhesion strength increased to 0.25-0.55 N/mm. These results showed that H2 addition was effective for preventing coloration and improving adhesion strength during long-period plasma treatment. Furthermore, the uniformity of surface treatment with Ar + H2 plasma was higher than that for Ar plasma.
关键词： Adhesion,Ag Ink,Printed Circuit Board for High-Frequency,Polytetrafluoroethylene (PTFE),Atmospheric Plasma Treatment
更新于2025-09-09 09:28:46
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PTFE Additive and Re-annealing Effect on Thermoluminescence Response of CaSO <sub/>4</sub> :Dy Derived from Co-precipitation Method
摘要： Effect of PTFE (Polytetrafluoroethylene) addition and re-annealing treatment in thermoluminescent dosimeter (TLD) CaSO4:Dy was investigated. CaSO4:Dy was prepared by a co-precipitation method. The PTFE was added before re-annealing treatment which the mass ratio of CaSO4:Dy and PTFE was fixed to 2:3. The re-annealing treatments of the samples were done at temperature 700 C for 1 hr. The obtained samples were characterized using a Fourier-transform infrared (FTIR) and X-ray diffraction (XRD) to observe the molecule bonding in sample and crystal properties, respectively. From the experimental results, it was observed that the thermoluminescence intensity of CaSO4:Dy, CaSO4:Dy re-annealed at 700 C, and CaSO4:Dy + PTFE re-annealed at 700 C are 57.03, 75.15, and 1191.11 nC, respectively. The intensity of 700 C-re-annealed CaSO4:Dy increased significantly after PTFE addition.
关键词： re-annealing,thermoluminescence,CaSO4:Dy,dosimeter,PTFE
更新于2025-09-04 15:30:14