Hydrophobic PTFE coatings on endoscopic lenses by RF magnetron sputtering

This study investigated the possibility of obtaining polytetrafluoroethylene (PTFE) coatings on Ti–6Al–4V titanium alloy substrates using electrophoretic deposition (EPD) and heat treatment. Different polyelectrolytes involving chitosan (CS), sodium alginate (SA), and PAZO were used, which enabled the deposition of PTFE particles of different sizes. Heat treatment changed the morphology of PTFE from particles to continuous coatings with high open porosity. In some of them, a network of micro-cracks was observed. PTFE coatings including a mixture of nanoparticles and submicroparticles deposited without mixing with CS or SA showed very high adhesion to the substrate and relatively high scratch resistance. The coatings were characterized by a high water contact angle, i.e., 145.4 ± 1.1° and 133.4 ± 4.0° for those deposited with CS and SA, respectively. Until the continuity of the coating was ensured at the friction contact point, the coatings showed very good sliding properties and a thin tribofilm was formed on the Al2O3 ball surface. The friction coefficient was 0.09 and 0.11 for the coatings obtained with CS and SA, respectively. However, the wear resistance of the coatings was poor and they were subject to significant deformation and intense abrasion. This work contributes to the understanding of PTFE coating fabrication processes based on EPD and heat treatment and shows that it is possible to obtain highly hydrophobic coatings exhibiting low-friction properties at low loads.

Erosion behavior of hydrophobic polytetrafluoroethylene (PTFE) coatings with different thicknesses

Influence of thickness of hydrophobic polytetrafluoroethylene (PTFE) coatings on cavitation erosion of hydro-machinery steel SS410

Manufacturers are increasingly substituting additive manufacturing for conventional manufacturing methods due to their ability to produce complex shapes. Polymer-based filament materials can be printed efficiently and inexpensively with fused deposition modeling. Coatings tend to augment the appearance of 3D printed objects as well as protect them from environmental influences. It is imperative to realize the physical and chemical properties of polymeric material like Acrylonitrile Butadiene Styrene (ABS) surfaces so as to design an optimal surface system. This work relates to the development of surface coatings on 3D-printed ABS parts. L9 orthogonal array was used with three 2 level factors for printing the samples. Specifically, the research compares surface characteristics of 3D-printed uncoated and coated ABS specimens. An aqueous solution containing Tricalcium phosphate and Chitin clear solutions in a 70:30 ratio was applied through immersion technique to create hydrophobic coatings. The coated and uncoated samples were characterized by employing various characterization tests, including dimensional accuracy (DA), surface roughness (SR), water contact angle (WCA), absorbency tests, scanning electron microscopy on fabricated parts. Assessment of wettability of 3D printed samples and impact of coating was accomplished via static contact angle measurements. In order to assess DA and SR before and after coating, digital vernier calipers were used in conjunction with a profilometer. In accordance with ASTM D570-98, water absorption tests were conducted for specified time. Results of investigation post coating showed no variation in dimensional accuracy, reduced SR and increased in WCA by ≥ 100 ̊. A reduction in water retention was observed after coating based on water absorption tests.

The silicon heterojunction (SHJ) solar cell has long been considered as one of the most promising candidates for the next-generation PV market. Transition metal oxides (TMOs) show good carrier selectivity when combined with c-Si solar cells. This has led to the rapid demonstration of the remarkable potential of TMOs (especially MoO x ) with high work function to replace the p-type a-Si:H emitting layer. MoO x can induce a strong inversion layer on the interface of n-type c-Si, which is beneficial to the extraction and conduction of holes. In this paper, the radio-frequency (RF) magnetron sputtering is used to deposit MoO x films. The optical, electrical and structural properties of MoO x films are measured and analyzed, with focus on the inherent compositions and work function. Then the MoO x films are applied into SHJ solar cells. When the MoO x works as a buffer layer between ITO/p-a-Si:H interface in the reference SHJ solar cell, a conversion efficiency of 19.1% can be obtained. When the MoO x is used as a hole transport layer (HTL), the device indicates a desirable conversion efficiency of 17.5%. To the best of our knowledge, this current efficiency is the highest one for the MoO x film as HTL by RF sputtering.

Sustainable cellulose nanocrystal based hydrophobic coatings with excellent self-cleaning and high thermal stability for multi-scenario applications

Conductive and transparent indium tin oxide (ITO) films with a thickness of 100 nm were deposited onto glasses and Si(100) wafers by direct current (DC) and radio frequency (RF) magnetron sputtering. The formation and the annealing effect of films were studied by the measurements of resistivity, optical-transmission, X-ray diffraction and scanning tunneling microscopy (STM). Experimental studies indicated those films deposited by DC sputtering in a 1% O2 in an O2/Ar gas mixture, without annealing, have the lowest resistivity and the highest transmission. In addition, the films deposited by RF sputtering in a 3% O2 in an O2/Ar gas mixture, with annealing in air at 300°C for 2 h, have better resistivity and transmission.

Electrochromic, optical and binding-energy performances of Tantalum Pentoxide and Zirconium dioxide films deposited with RF magnetron sputtering and cathodic arc plasma

Transparent, non-fluorinated, hydrophobic silica coatings with improved mechanical properties

The aim of this study is the generation of hydrophobic silica coatings on glass substrates using tetraethoxysilane and phenyl triethoxysilane using sol-gel method. The surfaces were characterized for their water contact angles, SEM, AFM, and FT-IR techniques. The concentrations of the phenyl triethoxysilane were investigated and optimized to obtain the best hydrophobic coating.

Fluorocarbon (FC) films were prepared on polyethylene terephthalate (PET) plates and PET fabrics respectively by a radiofrequency (RF) magnetron sputtering technique using polytetrafluoroethylene (PTFE) as a target. Scanning electron microscope and X-ray photoelectron spectroscopy were used to investigate the morphology, structure and composition of the obtained FC films. The hydrophobicity and uvioresistant properties of the FC film coated fabric were studied. The results show that the FC films were successfully deposited on the PET substrates by a RF magnetron sputtering. The deposited films are made up of four components -CF3, -CF2-, CF- and -C-. The proportions of the four components and surface morphologies of the deposited films vary with the sputtering conditions. Compared with the original fabric samples, the hydrophobicity of the FC film coated fabrics is quite good and improved significantly.

Fluorocarbon (FC) films were prepared on polyethylene terephthalate (PET) plates and PET fabrics respectively by a radiofrequency (RF) magnetron sputtering technique using polytetrafluoroethylene (PTFE) as a target. Scanning electron microscope and X-ray photoelectron spectroscopy were used to investigate the morphology, structure and composition of the obtained FC films. The hydrophobicity and uvioresistant properties of the FC film coated fabric were studied. The results show that the FC films were successfully deposited on the PET substrates by a RF magnetron sputtering. The deposited films are made up of four components -CF3, -CF2-, CF- and -C-. The proportions of the four components and surface morphologies of the deposited films vary with the sputtering conditions. Compared with the original fabric samples, the hydrophobicity of the FC film coated fabrics is quite good and improved significantly.

Self-assembled perfluoroalkylsilane films on silicon substrates for hydrophobic coatings

LiMPO4 (M=transition metal) has advantages of excellent structural and thermal stabilities, non-toxicity, low cost and excellent electrochemical properties. Among these compounds of materials, LiFePO4 is nontoxic and remarkably stable even in rough operating conditions. However, the problem of the low energy density of LiFePO4 resulting from its relatively low potential (~3.4 V) remains unresolved. LiMnPO4 has attracted tremendous attention due to the higher redox potential of Mn3+/Mn2+ vs. Li+/Li than that of Fe3+/Fe2+. However, there are numerous limitations related to its intrinsic electrochemical properties, mainly coming from the slow kinetics. Hence, the electrical conductivity is improved through carbon coating, Ag-embedded or the decrease in particle sizes in recent works. In this study, we find that the formation of a solid solution between LiFePO4 and LiMnPO4 is energetically favored, and each transition metal actively participates in the electrochemical reaction within a reasonable voltage range. Its electrochemical properties and phase stability are explored with continuous composition spread (CCS) radio frequency (RF) magnetron sputtering. We describe for Ag-doped olivine based cathode materials deposition on Pt/Ti/SiO2/Si substrates. The olivine compound Ag-doped thin film cathode materials was deposited by CCS RF magnetron sputtering. The CCS RF sputtering is a feasible method to deposit various compositions on a substrate with two targets. Two independent RF magnetron sputtering guns installed with LiFePO4 and Ag-doped LiMnPO4 targets are located vertically to a Pt/Ti/SiO2/Si substrates. Consequently, we have investigated the full range of LiFePO4 and LiMnPO4 compositions to find optimized composition with continuous composition spread RF magnetron sputtering.

Acrylonitrile Butadiene Styrene (ABS) polymer and Polytetrafluroethylene (PTFE) polymer has different properties individually. In this work ABS is used as matrix and PTFE is used as particle reinforcement. ABS is a copolymer containing butadiene, styrene and acrylonitrile. This work is to focus about the thermal property of ABS copolymer by adding PTFE as particle in polymer composites. From the analysis PTFE fit into a perfect particle reinforcement material for a broad assortment of utilizations. The samples is prepared with 100% ABS and 10% PTFE by weight, 20% PTFE is added to ABS and fabricated with Injection molding process. The addition of PTFE to ABS has improved on thermal properties. Experiment results shows that PTFE filler added composites exhibited high thermal conductivities and good coefficient of linear thermal expansion when compared with pure ABS copolymer.