Fluorine In Films Research Articles

Fabrication of a durable omniphobic thin film and its application in precision nozzles

The ultrafine nozzles used in micropatterning processes easily encounter pollution on the nozzle surfaces, such as clogging, liquid clumping, and bond tailing. In this study, an omniphobic functional film was developed by an initiated chemical vapor deposition (iCVD) method and used to fabricate an antifouling nozzle. In the iCVD process, polymeric fluorine films were grown under optimized conditions, and their durability was analyzed through abrasion and nanoscale cutting tests to evaluate the surface wear resistance and adhesion strength, respectively. Two omniphobic films, prepared using homopolymer p(C6FMA) and copolymer p(C6FMA-co-DVB), were compared; the p(C6FMA-co-DVB) film was determined to have a superior durability than the p(C6FMA) film. Consequently, the p(C6FMA-co-DVB) film was deposited on both the inside and outside surface of a nozzle of diameter 0.3 mm. The oleophobicity was examined by comparing the discharge rates of a high-viscosity epoxy paste containing metal powders in coated and bare nozzles. The bare nozzle exhibited significant variations in discharge volume and frequently experienced clogging, while coated nozzles demonstrated consistent discharge rates and remained unclogged. These findings suggest that the proposed thin film coating has the potential to increase the lifespan and efficiency of ultra-fine nozzles in the automated micro-patterning industry.

Investigation of the Structural, Optical and Electrical Properties of Zinc Oxide Co-Doped with Fluorine and Cobalt

Zinc oxide codoped with Fluorine and Cobalt thin films (FCZO) were successfully synthesized on heated glass substrate at 380 °C by spray pyrolysis technique. The influence of doping and codoping on the structural, optical and electrical properties were investigated. X-ray diffraction results showed that the undoped and FCZO films exhibit the hexagonal wurtzite crystal structure with a preferential orientation along [0 0 2] direction. No secondary phase is observed in FCZO films. The optical transmittance of Co doped ZnO thin films reduces up to 80 % as compared to undoped ZnO thin film in the visible region. We have observed three absorption bands at 568, 608 and 659 nm which can be attributed to the d-d transitions of tetrahedrally coordinated Co2+ ion in the high spin state. The band gap was found to be increasing in the range of 3.26-3.39 eV with Co doping whereas it decreases for higher doping of Co concentration.

Investigations of the characteristics and chemical bonds of Al and F co-doped ZnO films as a function of F2flow rate

In this study, we investigate the effect of fluorine (F[Formula: see text] flow rate on the crystal characteristics and chemical bonds of Al-Doped ZnO (AFZO) Films. At first, 1 wt% Al2O3was mixed with 99 wt% ZnO to form the Al-doped ZnO ceramic target, the radio frequency (RF) magnetron sputtering method was used to deposit the AFZO films by introducing different flow rates of F2gas using F2/(Ar + F2) mixing atmosphere during the deposition process. F2flow rates (F2/(Ar + F2)) were changed in the range of [Formula: see text]%, and F2ratio was controlled using the mixing gases of (F2(5%) + 95% Ar) and pure Ar. AFZO films were deposited on the EagleXG glass and the films’ thickness was about 330 nm by controlling the deposition time. After AFZO films were deposited, their crystalline structure and electrical characteristics were well investigated. Finally, a comparative study of surfaces of AFZO films was investigated using X-ray photoelectron spectroscopy (XPS) to find the variations of the chemical bonds as the deposition temperature and F2flow rate were changed.

Engineered Multifunctional Fluorinated Film Based on Semicontinuous Emulsion Polymerization Using Polymerizable Quaternary Ammonium Emulsifiers

Along with society’s progress, high-quality coatings are widely used. Although fluorinated polymers were successfully prepared by semicontinuous emulsion polymerization with surfactants, chlorotrifluoroethylene (CTFE), and acrylate monomers, the optimization collocation of surfactants still has room for improvement. The traditional emulsifiers are physically absorbed onto the surface of latex particles. The latex film generated by latex particles is unstable in water, which limits its application. Herein, a novel series of cationic quaternary ammonium polymerizable surfactant was selected because it can react with CTFE and acrylate monomers and can become a part of the polymers. We also studied the effects of emulsifier type on resultant emulsion properties. In addition, wonderful weatherability, water resistance, and antibacterial and antifouling of the multifunctional fluorinated films were observed, which would open up a bright future for coating industries.

Preparation and Properties of Thiol-Ene UV-Curable Fluorinated Emulsion

Single electron transfer living radical emulsion polymerization (SET-LRP) of allyl methacrylate (AMA) coupled with 2,2,3,4,4,4-hexafluorobutyl methacrylate (HFBA) was investigated in the presence of Cu(0)/N,N,N’,N’’,N’’-pentamethyldiethylenetriamine (PMDETA) as catalyst and ethyl 2-bromoisobutyrate (EBiB) as initiator. Solid content of the emulsion and the amount of the catalyst, initiator and emulsifier were discussed for the optimal reaction conditions. Then, the emulsion was combined with thiol capped polyurethane (SHPU) under UV to form the UV curable fluorinated films. Mechanical properties and contact angle of the UV cured films were studied.

Fabrication of Transparent Conductive Zinc Oxide Co-Doped with Fluorine and Zirconium Thin Solid Films by Ultrasonic Chemical Pyrolysis: Effects of Precursor Solution Aging and Substrate Temperature

Highly transparent, conducting zinc oxide [ZnO] thin films co-doped with fluorine and zirconium have been deposited on glass substrates by the ultrasonic chemical spraying technique. The effects of aging of the starting solution and substrate temperature on the structural, morphological, and electrical properties of the ZnO:F:Zr films have been studied. The resistivity of the films decreases with the aging time of the starting solution until the seventeenth day reaching a minimum of about 1.2×10−2 Ω cm and then increases. Though all the samples are of polycrystalline hexagonal wurtzite type and grow preferentially with (002) plane parallel to the substrate, their morphology depends strongly on the aging time of the reaction solution. The optical transmittance of all the films remained around 80% in the visible spectral range. These highly transparent, low resistive thin films are expected to be highly useful as transparent electrodes in the fabrication of thin film solar cells.

Structural and optical characterization of film deposited by pulsed plasma thruster plume

In order to study the characteristics of the films deposited by pulsed plasma thruster plume and assess contamination arising from the exhaust plume, the compositions of the pulsed plasma thruster plume are studied by means of mass spectrum analysis, the structural properties of the films deposited at different angles on the cathode side of the thruster are investigated by X-ray photoelectron spectroscopy, Fourier transform infrared absorption spectroscopy, and the optical properties of the films are studied by ultraviolet-visible light spectrophotometry. The results show that the plume consists primarily of C, F, CF, CF2, CF3, that low fluorine-carbon ration carbon fluorine films are deposited by pulsed plasma thruster plume, and that the chemical bondings and structures of these films present different trends in different regions with 30 degree angle as the boundary. These films basically show that they have strong absorption properties for wavelengths below 500 nm and have enhanced reflective characteristics. Due to influence of the characteristics of the deposited films, the optical properties of these films present signigicant angular dependences.

Effects of crystallisation behaviour of mould fluxes on properties of liquid slag film

During the continuous casting of medium carbon steel slabs, stable liquid slag film performance is necessary to ensure that the process runs smoothly. In this paper, the effects of mould flux crystallisation behaviour on the properties of leftover liquid slag films were examined. First, the compositions of the leftover liquid slags of high fluorine, CaO–SiO2–TiO2 and CaO–SiO2–Na2O based mould fluxes after a single crystalline phase was separated were calculated. Then, the viscosity, melting temperature, break temperature and degree of crystallisation of each leftover liquid flux were measured. The results revealed that the properties of leftover liquid slag films of CaO–SiO2–TiO2 and CaO–SiO2–Na2O based mould fluxes are not as stable as those of high fluorine films after crystallisation. This paper provides a new method for developing fluorine free mould fluxes and for determining the most suitable type of crystalline phase that should be utilised in the continuous casting of medium carbon steel slabs.

Development of Millimeter-Wave Planar Antennas Using Low-Loss Materials

As the importance of advanced millimeter-wave diagnostics increases, the fabrication of high-performance devices and components becomes essential. In this paper, we describe the development of millimeter-wave planar antennas using low-loss fluorine substrates. The problems to be solved in this study are the low degree of adhesion between copper foil and the fluorine substrate and the accuracy of device pattern using conventional fabrication techniques. In order to solve these problems, a new surface treatment of fluorine films and a fabrication method using electro-fine-forming (EF2) are proposed. In order to confirm the performance of the treated films, microstrip lines (MSLs) and planar patch antennas with a low sidelobe level in the E-plane are designed and fabricated on conventional fluorine substrates and grafted poly(tetrafluoroethylene) (PTFE) films.

Advanced Fabrication Method of Planar Components for Plasma Diagnostics

Kyushu Hitachi Maxell, Ltd, Tagawa-gun, Fukuoka 822-1296, Japan(Received 4 December 2006 /Accepted 11 March 2007)As the importance of plasma imaging diagnostics increases, the fabrication of high performance millimeter-wave planar components becomes essential. This paper describes the development of high performancemillimeter-wave planar components such as antennas and filters using a low-loss fluorine substrate. The prob-lems to be solved are the low degree of adhesion between copper foil and the fluorine substrate and the shape ofthe antenna pattern. In order to solvetheproblems, surface treatment of fluorine films and a fabrication methodusing Electro Fine Forming (EF2) are utilized.

Ultrathin carbon–fluorine film processing

In conventional plasma polymerization processes, the bulk properties of the treated substrates are maintained whereas the surface properties are changed to the ones of the coating polymer. In contrast, materials with ultrathin non-closed layers and domains of plasma deposited compounds can show combined properties (from the surface of the bulk material and the non-closed layer) or even completely new behavior. This can be seen by analyzing e.g. the wettability (contact angle), the tribological properties, chemical functionalities or biological interactions.Ultrathin closed and non-closed films (domains) of fluorocarbon polymer were produced by means of RF-CVD (radio frequency aided chemical vapor deposition, plasma polymerization) with CHF3 as monomer gas; argon was added as additional process gas. Our work has been carried out in a symmetric capacitively coupled reactor at 13.56 MHz in the low-pressure, glow-discharge regime. The influence of pulsing the plasma by varying on- and off-times on the surface properties were investigated on silicon wafers as substrates. The obtained functionalized surfaces were characterized by means of advancing and receding contact angle measurements, X-ray photoelectron spectroscopy (XPS) as well as atomic force microscopy (AFM).

Physical and chemical aspects of long-term biodeterioration of some polymers and composites.

A biodeterioration study was performed on synthetic polymeric materials including homogenous film made from poly(tetrafluorine ethylene), copolymer film made from tetrafluorine ethylene and perfluoromethyl vinyl ether, vulcanized rubber containing natural caoutchouc, and vulcanized rubber, the main component of which was synthetic butadiene nitrile caoutchouc. The materials were exposed for 12 years to the open air, in mycological containers, and in a cellar in maritime climate conditions: air humidity 72%-90% and seasonal average temperature of 17 degrees C in summer and -2.5 degrees C in winter. The studies of optical and electron microscopy revealed that microorganisms were able to develop not only on the surface of the materials but also to penetrate inside into deeper layers. The fungi that produced the most intensive deterioration in the fluorine polymers and vulcanized rubbers belonged to the Alternaria, Aspergillus, Aureobasidium, Cladosporium, Penicillium, Oidiodendron and Trichoderma genera. The fungi Aspergillus fumigatus, A. niger, Aureobasidium pullulans, and Trichoderma viride produced the most intensive deterioration in the fluorine films, whereas Alternaria tenuissima, Cladosporium herbarum, C. sphaerospermum, and fungi of the Oidiodendron genus were widespread on vulcanized rubbers. Fungi of the Aspergillus and Penicillium genera prevailed on both fluorine films and rubbers exposed in a cellar. Infrared spectroscopy indicated that the structures of poly(tetrafluorine ethylene) and the copolymer of tetrafluorine ethylene and perfluoromethyl vinyl ether did not change after the 12-year exposure; only insignificant changes in surface morphology were observed by optical microscopy. Vulcanized rubber made both from natural and from synthetic caoutchouc exposed for the same length of time showed rather evident changes in appearance and structure. X-ray graphical analysis revealed that new crystallization of the caoutchouc and a possible change in chemical composition of the fillers had occurred.

Hard amorphous carbon–fluorine films deposited by PECVD using C 2H 2–CF 4 gas mixtures as precursor atmospheres

An investigation of the structural arrangement and mechanical properties of a-C:F:H films obtained by plasma enhanced chemical vapor deposition (PECVD) using C 2H 2–CF 4 gas mixtures as precursor atmospheres was carried out. The results indicate that fluorine incorporation increases the hydrophobicity of the films and relaxes the internal stress, while reducing the hardness also. It was shown that it is possible to obtain fluorinated carbon films with hydrophobicity comparable to that of polytetrafluoroethylene (TFE) but with much higher hardness, that is in the range of a few GPa.

Electrochemistry of fluorine production

The electronic properties of carbon–fluorine films (denoted C–F) formed on carbon electrodes in KF–2HF during fluorine evolution reaction were investigated in aqueous solution containing a redox couple and in mercury. It was shown that the passivating C–F films behave as electronic conductors. STM measurements have shown composition heterogeneities at the surface of fluorinated HOPG (conducting ans insulating areas). The influence of the amount of insulating graphite fluorides on the surface of the electrodes was demonstrated. Thus, the high anodic overvoltage observed during fluorine evolution on C/C–F anodes in KF–2HF is mainly attributed to the poor wettability of the electrodes by the melt, which results in a small electroactive area. A new model was proposed for representing the electrode/electrolyte interface; it includes the presence of a “fluidized” layer between the surface C–F film and the fluorine gas film. The “fluidized” layer is composed of liquid KF–2HF melt and dissolved fluorine gas. The influence of the mass transfer phenomenon occurring in that layer was pointed out mainly by impedance measurements. Finally, the contributions of the C–F film, η C–F, and of the “fluidized” layer, η fluid, to the total anodic overvoltage, η T, were studied using a numerical calculation method. Both contributions must be taken into account for a global understanding of the fluorine evolution process.

Pulsed plasma deposition from 1,1,2,2‐tetrafluoroethane by electron cyclotron resonance and conventional plasma enhanced chemical vapor deposition

AbstractPulsed electron cyclotron resonance (ECR) plasmas from 1,1,2,2‐C2H2F4 are used to deposit fluorocarbon films. The deposited films have a F : C ratio of 1, with only slight variations in % CFx as the deposition pressure is decreased. The optical emission (OES) spectra of the pulsed C2H2F4 plasmas show high intensity peaks for H, C2, and C3, with lower intensity CF2 and F peaks. The dominant OES peak shifts from Hα to C2 when the pressure is reduced, most likely a result of the increased electron temperature at the lower pressure. Gas‐phase recombination reactions may be occurring between the OES sampling region and the deposition substrate (∼ 8‐in. distance), producing fluorocarbon molecular deposition species, thus accounting for the high degree of fluorination in the deposited films. Parallel plate plasma deposited films from C2H2F4 show less fluorination than their ECR counterparts, as well as vastly different OES spectra, with CF2 peaks dominating the spectra versus H and C2. The presence of ion bombardment in the parallel plate system tends to defluorinate the depositing films, and thus can account for the less fluorinated films deposited in the parallel plate versus ECR systems. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2084–2092, 2001

Kinetics of fluorine evolution reaction on carbon anodes: influence of the surface CF films

During the fluorine evolution reaction by electrolysis of molten KF–2HF, a thin solid fluoro-carbon layer is formed on carbon anodes. This film is mainly composed of fluorine–graphite intercalation compound and a small amount of insulating graphite fluorides. Impedance measurements performed in mercury and cyclic voltammetry studies in aqueous solution containing a redox couple have shown that the surface film behaves like an electronic conductor and cannot constitute a high energy barrier for the electron transfer in electrochemical reactions. However, the kinetics of the fluorine evolution reaction is strongly dependent on the water content in KF–2HF, indeed, water contributes to the formation of graphite fluorides which limit the fluorine evolution reaction. STM measurements performed on crude and passivated highly oriented pyrolitic graphite (HOPG) samples have pointed out the heterogeneities of composition of this carbon–fluorine film and the influence of water. It has been shown that, if the passivation of the carbon electrodes was performed in molten KF–2HF containing a high amount of water, the hexagonal symmetry of the images obtained with HOPG is lost.

X-ray Induced Modification of Semifluorinated Organic Thin Films

The X-ray induced modification/defluorination of semifluorinated self-assembled monolayers (SAMs), based on 1H,1H,2H,2H-perfluorodecanethiol (CF3(CF2)7(CH2)2SH) has been studied using X-ray photoelectron spectroscopy (XPS). At short irradiation times X-ray induced defluorination of the semifluorinated SAM exhibits first-order kinetics with respect to the film's fluorine concentration. The evolution of the C(1s) region during modification is consistent with a kinetic model of defluorination involving consecutive C−F bond breaking events (e.g., CF2 → CF). Relative defluorination rate constants obtained for the different fluorine-containing functionalities (e.g., CF2, CF) provide support for a stochastic fluorine loss process, where each individual C−F bond is initially equally labile toward dissociative electron attachment, independent of local chemical environment. Upon atmospheric exposure the modified film's oxygen adsorption characteristics demonstrate that the density of radicals produced within the or...

Fluorine evolution at carbon/KF–2HF interface

A solid carbon–fluorine film (C–F) is formed on carbon electrodes during fluorine evolution reaction in KF–2HF. Impedance spectra performed with C/CF/Hg structures do not exhibit any capacitive loop whereas the Ta/Ta2O5/Hg structures do, owing to the insulating properties of the tantalum oxide film. It was concluded that the passivating C–F films behave as electronic conductors. Same conclusions were deduced from the study of the kinetics of the electron transfer of the FeIII/II redox couple in aqueous solution, using a C/C–F electrode. One can deduce that the electrons may be transferred easily through the C–F film from the carbon substrate to the electrolyte during the fluorine evolution reaction in KF–2HF. Therefore, the high anodic overvoltage observed during fluorine evolution reaction is mainly attributed to the poor wettability of the electrodes by the melt, which results in a small electroactive area. Surface analyses by STM measurements have pointed out heterogeneities of composition at the surface of fluorinated highly oriented pyrolitic graphite. Hexagonal symmetry was observed as well as an overlap of the electronic densities between two neighbouring atoms which was interpreted by the existence of chemical bonds between one fluorine species with one or two carbon atoms.

Electronic properties of passivating compounds: application to the fluorine evolution reaction

The electronic properties of carbon–fluorine films (denoted C–F) formed on carbon electrodes in KF–2HF during fluorine evolution reaction were investigated. Impedance spectra obtained with C/C–F/Hg, C/PbO 2/Hg and Ta/Ta 2O 5/Hg structures were compared. The latter exhibits a capacitive loop whereas the former does not. However, if a breakdown of the Ta 2O 5 oxide occurred, the capacitive loop is not observed, as in the case of C/PbO 2/Hg structures which are characterised by the electronic conductivity of PbO 2. The passivating C–F films formed on carbon anodes in KF–2HF behave as electronic conductors. This result was confirmed by studying the kinetics of the electron transfer of the Fe III/II redox couple in aqueous solution, using a C/C–F electrode. These electrodes behave like metallic platinum electrodes. The influence of the amount of insulating graphite fluorides on the surface of the electrodes was demonstrated. Thus, the high anodic overvoltage observed during fluorine evolution on C/C–F anodes in KF–2HF is mainly attributed to the poor wettability of the electrodes by the melt, which results in a small electroactive area. STM measurements have shown composition heterogeneities at the surface of fluorinated HOPG. Moreover, hexagonal symmetry was pointed out; the electron density map is interpreted on the basis of bonding of HF 2 − species to carbon atoms.

Characterizaton of Pecvd Fluorinated Silicon Oxides and Stabilization of Interaction with Metals

ABSTRACTFluorinated silicon oxide films were prepared in a plasma enhanced chemical vapor deposition reactor using TEOS, O2, and either C2F6 or NF3. Properties such as deposition rate, film refractive index, dielectric constant, density, and fluorine concentration were investigated as a function of experimental conditions. Based on nuclear reaction analysis (NRA) and Fourier Transform Infrared (FTIR) measurements, no single linear relationship was found between fluorine concentration or film density and dielectric constant. Special attention was paid to the interaction of fluorine with metals. NRA and X-ray photoelectron spectroscopy (XPS) depth profiles showed that fluorine diffuses rapidly through aluminum and piles up at the free surface. The effect of various plasma treatments was investigated to passivate the surface of fluorinated silicon oxide. CF4 - O2 plasma treatment of the fluorinated oxide before aluminum deposition produced significant improvement in inhibiting fluorine diffusion into aluminum without increasing the dielectric constant.