PTFE Film Research Articles

Super Toner and Ink Repellent Superoleophobic Surface

Offset of imaging material from a fuser surface to paper during fusing is highly undesirable in printing. Here the wetting and repellent characteristics of three imaging materials (a solid wax ink, a waxy polyester toner, and a polyester toner) in their molten states have been studied on three model print surfaces: a transparency (surrogate for paper), a PTFE film, and a model superoleophobic surface, with the aim of assessing their performance in fusing. The superoleophobic surface, with water and hexadecane contact angles of ∼156° and sliding angles at ∼10°, comprises 3 μm diameter pillar arrays on silicon wafer and was fabricated by photolithography followed by surface modification with a fluorosilane. The contact angles of the three imaging materials range from 40 to 79° on the transparency and the sessile drops do not slide even at 90° tilted angle, indicating that they all wet, adhere, and pin on the transparency. Although the contact angles of the three imaging materials are slightly higher (63-85°) on PTFE, the sessile drops do not slide on PTFE either. Because PTFE is widely used as a fuser surface material in combination with different waxy imaging materials commercially, we attribute the successful implementation of PTFE to the use of the wax additive. With the superoleophobic surface, there is a dramatic increase in advancing and static contact angles for all three imaging materials. The advancing and static contact angles are in the 150-168° range for waxy toner, indicative of superhigh repellency. Although the advancing and static contact angles for the polyester toner decrease slightly at 147 and 130°, respectively, the repellency is still very high. More importantly, the sessile drops of all three imaging materials are mobile upon tilting and they all have high receding contact angles. The overall results suggest that the adhesion between the superoleophobic surface and the ink and toner materials are very small relative to those with paper and PTFE. The important of high repellency and low adhesion to offset performance is discussed.

Preparation of polytetrafluoroethylene porous membrane based composite alkaline exchange membrane with improved tensile strength and its fuel cell test

A strategy to improve the alkaline exchange membrane tensile strength was introduced based on porous PTFE and quaternized polyvinyl benzyl chloride (qPVBz/OH−). A thin PTFE film was used as the support to prepare the composite AAEM to improve the mechanical strength. Tensile stress tests showed 51.1 MPa which was twice that of the pure anion exchange membrane qPVBz/OH−. SEM observations showed that the pores of the PTFE were successfully filled with qPVBz/OH− polymer and there was no structure defects in the cross-section of the resultant membrane. The synthesized composite membrane had very good thermal stability. The through plane ionic conductivity was in the range of 1.65 × 10−2 to 2.2 × 10−2 S cm−1 in the temperature range of 25 °C–60 °C. The power density of H2 and O2 fuel cell gave 162 mW cm−2.

Multilayer composite material based on plasma-modified PTFE films

216 The surface of PTFE is known to be the most hydrophobic among polymer materials [1]. The con tact angle (of water) is ≥120° [2]; however, low tem perature plasma treatment can substantially alter the contact properties of polytetrafluoroethylene [3, 4]. Earlier, we studied the surface modification of PTFE films in dc discharge [2] and showed that such a treat ment can result in substantially lower values of the contact angle (θ) and higher values of the work of adhesion and surface energy as compared with other methods of modification of this polymer. For exam ple, θ of water was 33° or 49° after modification at the anode and cathode, respectively, and the total surface energy increased from 13.18 to 61.5 or 50.7 mJ/m2, respectively. These findings open a possibility for resolving the applied problem of manufacturing mul tilayer composite materials, including nanosized metal layers and thin PTFE films, which is important for electrical engineering and electronics.

Hydrophobicity study of polytetrafluoroethylene nanocomposite films

In the present work, inorganic fullerene-like tungsten disulfide (IF-WS2) nanoparticles have been incorporated into polytetrafluoroethylene films using aerosol-assisted deposition process. The hydrophobic behavior of the nanocomposite film has been investigated and the result shows that the hydrophobicity of PTFE films can significantly be improved with the incorporation of IF-WS2 nanoparticles. An oblate spheroid model which takes into the consideration of surface roughness effect has been proposed, to simulate the hydrophobic behavior, based on the surface roughness and peak density of the nanocomposite films. This hydrophobic model can provide a useful guideline to describe and predict the hydrophobicity of nanocomposite films, from the input of parameters such as surface energy, roughness and liquid properties.

Minimizing frictional sound of PU-Nanoweb and PTFE film laminated vapor permeable water repellent fabrics

To investigate sound characteristics of PU-Nanoweb (NW) and PTFE film (PTFE) laminated vapor permeable water repellent fabrics, their frictional sounds by walking, jogging, and running speeds were recorded and sound characteristics such as SPL, loudness (Z), sharpness (Z), roughness (Z), and fluctuation strength (Z) were calculated. Mechanical properties were measured by KES-FB system. SPL and fluctuation strength (Z) were significantly increased by increasing speed. Roughness (Z) was generated to be the highest by jogging and running speeds. However, sharpness (Z) was decreased by increasing speeds. NW had significantly lower SPL, loudness (Z), but had higher roughness (Z) than PTFE. NW significantly had less B (bending rigidity), G (shear stiffness), WC (compressional energy), and W (weight). These distinctions influenced the sound characteristics to have the different sound between NW and PTFE. The sound would be low by controlling the mechanical properties and laminated nanoweb and film conditions. The crucial factors were RC and laminated nanoweb and film weight to minimize SPL and loudness (Z) of NW and PTFE at all speeds.

Evaluation of PEFC Membrane based on Cross-linked PTFE by EB Grafting: Effect of Thickness for FC Performance

The performance of a polymer electrolyte fuel cell (PEFC) was affected by the thickness of the thin proton exchange membrane (PEM). The PEMs with the different thickness were prepared by radiation induced grafting of styrene into the radiation-cross-linked polytetrafluoroethylene (RX-PTFE) membrane prepared from PTFE dispersion, and then sulfonated. The wet thicknesses of the obtained thin PEMs were lower than 25 μm. A PEM based on a 50 μm PTFE film, with the wet thickness of 73 μm, was also prepared under the same procedure for the comparison. The obtained PEMs were characterized in term of gas cross-over. The surface of platinum / carbon electrodes was coated with Nafion ® dispersion, and then membrane electrode assembles (MEAs) were prepared by the hot-pressing. The polarization curves and electrochemical impedances of the thin PEMs in a single fuel cell were analyzed. As a result, the cell performance of the MEA based on thinner PEM tended to give higher power density and current density. On the other hand, the performance of the thinnest PEM (13 m) decreased, and the MEA based on the thinner PEM gave the lower open circuit voltage (OCV) due to the higher gas cross-over. Thus, the thin PEM based on RX-PTFE had shown a high performance at the suitable thickness.

Laminated Composite on the Basis of Plasma Modified PTFE Films and Thin Aluminum Layers

Laminated Composite on the Basis of Plasma Modified PTFE Films and Thin Aluminum Layers

Surface Morphology Control of Polymer Films by Electron Irradiation and Its Application to Superhydrophobic Surfaces

A simple and controllable one-step method to fabricate superhydrophobic surfaces on poly(tetrafluoroethylene) (PTFE) films is developed on the base of electron irradiation. When the thickness of PTFE films is higher than the penetration depth of electron beams, electrical charging occurs at the surface of the films because of the imbalance between the accumulation of incident electrons and the emission of secondary electrons. Local inhomogeneity of charge distribution due to this electrical charging results in the nonuniform decomposition of PTFE molecular bonds. As electron fluence increases, surface morphology and surface roughness of the films are dramatically changed. An extremely rough surface with micrometer-sized pores is produced on the surface of PTFE films by electron irradiation at a fluence higher than 2.5 × 10(17) cm(-2).Because of high surface roughness, the irradiated PTFE films exhibit superhydrophobic property with a water contact angle (CA) greater than 150° at fluences ranging from 4 × 10(17) to 1 × 10(18) cm(-2). The surface morphology and corresponding water CA can be controlled by simply changing the electron fluence. This electron irradiation method can be applicable to the fabrication of superhydrophobic surfaces using other low-surface-energy materials including various fluoropolymers.

Electrogeneration of hydrogen peroxide on a novel highly effective acetylene black-PTFE cathode with PTFE film

A novel acetylene black-PTFE cathode for electrogeneration of hydrogen peroxide (H 2O 2) was fabricated using acetylene black powder (ABP) as catalyst, PTFE as binder. The effect of mass ratio of ABP to PTFE, solution pH (3–11), applied current density (5–20 mA cm −2) and surface hydrophobic property on the activity and useful life of cathode was investigated using a two-electrode undivided cell fed with air at 2 L min −1 in Na 2SO 4 solution of 0.05 M, and the characteristics of cathode were examined by FTIR spectra, BET measurement, SEM image and CV study. The experimental results showed that: (1) so far the activity of cathode is the highest for the electrogeneration of H 2O 2 with air feed, at pH 3 and the current density of 20 mA cm −2 the average H 2O 2 generation rate reaching 58.9 mg L −1 h −1 cm −2 during 150 min of electrolysis and the current efficiency being 92.7%; (2) a proper and stable surface hydrophobic property could significantly increase the useful life of cathode; (3) the cathode had a remarkable restoration and regeneration performance.

The Surface Characteristics and Friction Properties of PTFE Yarn

To discuss the surface characteristics and friction properties of PTFE yarn, the longitudinal structure and cross section were analyzed, it were investigated that the influence on friction coefficient of running speed, guide material and initial tension on ring spinning for producing PTFE film yarn. The results show that the longitudinal section of PTFE yarn was regular cylinder, the cross section was polygon, the yarn surface was very smooth, not easy to absorb dust, PTFE yarn had very good self-cleaning function. The friction coefficient of PTFE yarn was decreased at first with the increase of running speed but increased later, and the friction coefficient of PTFE yarn was reduced with the increase of initial pressure. The friction coefficient between PTFE yarn and plastic was very small, it can be said that plastic was the best guide material for ring spinning of PTFE yarn. Introduction

Hydrophobic Properties of PTFE Films Prepared by PVD and CVD Process for Anti-Pollution Coating in Optoelectronics

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Unidirectional Alignment of Carbon Nanotube Aggregates Using Friction-transferred Polymeric Films

Abstract Aggregates of single-walled carbon nanotubes (SWCNTs) were deposited unidirectionally on highly oriented PTFE film made by friction transfer. The friction-transferred PTFE film possesses many straight channels of various sizes running along the transfer direction. SWCNT aggregates were preferentially deposited parallel to the channels when SWCNTs in a form of dry powder were sprinkled, as confirmed by Raman microscopy and anisotropic electrical resistivity. Furthermore, the SWCNT film can be transferred to another substrate surface by simply stamping the SWCNT/PTFE film on it.

Effect of Sputtering Process Conditions on Microstructure and Mechanical Properties of Pt-Fe Nano Film

One of the vertical magnetic recordings medium materials of the hard disk drive (HDD) is a Pt-Fe thin film. The development of ultra-high density magnetic recording medium in next generation is expected the magnetic disks such as HDD with capacity enlargement of the data. In order to study effectiveness of the proposed sputtering method, we evaluated micro structure, magnetic and the mechanical properties of a Pt-Fe thin film by some sputtering process conditions. From research results, effect sputtering conditions on micro-structure and mechanical properties of Pt-Fe nano film are verified.

Thermo-responsive Property of PTFE-g-P(NIPAAm-co-HIPAAm) Films Prepared by the use of Ar Plasma Treatment

Poly(tetrafluoroethylene) (PTFE) films grafted with P(NIPAAm-co-HIPAAm) have been prepared by the combined use of the Ar plasma treatment and photografting. By the Ar plasma treatment the hydrophilicity of PTFE film surface was achieved by irradiation of the short time. The surface compositions of the grafted PTFE films were analyzed by ESCA and the thermo-responsive properties were investigated by contact angle measurements toward water. The composition of HIPAAm in the monomer mixture was controlled to aim for increasing the phase transition temperature of PNIPAAm, 32°C. The phase transition temperature of ePTFE-g-P(NIPAAm-co-HIPAAm) film increased with the ratio of HIPAAm in the monomer solution. The transition temperatures of ePTFE-g-P(NIPAAm-co-HIPAAm) (N:H=70:30, 50:50 and 20:80) films were about 40°C , 52 and 83°C, respectively. It is thought that the Ttr of the ePTFE-g-P(NIPAAm-co- HIPAAm) film can be set more minute by regulating the composition of HIPAAm. Therefore, many applications in wide fields will be developed in future.

250°C Operating Temperature Dielectric Film Capacitors

High operating temperature electronic components are needed for a variety of military, aerospace, down-hole, and electric vehicle applications. One of the limiting technologies is the availability of highly reliable capacitors that operate at temperatures greater than 150°C and up through 250°C. This paper introduces a high breakdown strength dielectric film Gore has developed for metallized film capacitors. In addition to exceptionally high breakdown voltages, the 6 μm PTFE film exhibits low dissipation factor and stable capacitance over a wide temperature range. Film properties were tested from −50°C to 250°C and both wound film/foil and metallized film capacitors were fabricated and tested from RT to 300°C.

Comparative Study between Sulfonation and Phosphoration forCommercial PTFE grafted with Styrene for Fuel Cell Application

Simultaneous gamma irradiation was used for grafting of styrene onto commercial PTFE films. Different parameters affecting the grafting such as solvent, irradiation dose and monomer concentration were investigated. Sulfonation was performed using chlorosulfonic acid while phosphoric acid treatment was done in advance. Studying the role of phosphoric acid treatment for facilitating sulfonation of styrene grafting the PTFE membranes was carried out. FTIR spectroscopy and X-ray diffraction study confirmed the grafting and furthermore phosphoration and / or sulfonation. Scanning electron(SEM) was performed to characterize the morphological structure. Mechanical properties were discussed by measuring the hardness while chemical stability measurement assure their duration availability. Thermal characterization was investigated to proved the membrane applicability through wide range of temperature. Water uptake and ion exchange capacity were determined prior to measure the electrical conductivity and capacitance at different frequencies to assure the applicability of the grafted membranes in the fuel cell. Raising the temperature to 80°C increasing the Ec value to 1.08 x 10 -1 S/cm which is well comparable to that of Nafoin.

Preirradiation Graft Polymerization of Styrene in a Poly(tetrafluoroethylene) Film Investigated by Time-Resolved Small-Angle Neutron Scattering

Preirradiation graft polymerization of styrene in a poly(tetrafluoroethylene) (PTFE) film was examined by time-resolved small-angle neutron scattering (SANS). A crosslinked PTFE film, thickness of which is about 50 μm, was irradiated byγ-ray and immersed in a mixed solvent of styrene monomer and toluene. SANS elucidated that graft polymerization proceeds by two reaction processes (I) and (II). In process (I) at min, graft polymerization occurs at an interface between crystalline and amorphous PTFE domains and the grafted polystyrene segregates from PTFE, forming a thin layer with a sharp interface. In process (II) at min, grafted PS layer starts to bridge between crystalline domains. At the end of process (II), 40% of total crystalline PTFE domain is covered by the grafted PS chains.

Formation of Gold Nanoparticle Chains in a Flow Cell Coated with Oriented Polymer Thin Films

Gold nanoparticle chains are expected to be one of novel photonics materials in the next generation. We previously reported the formation of the gold nanoparticle chains from a colloidal gold solution on a glass substrate coated with oriented thin films of poly(tetrafluoroethylene) (PTFE). According to the proposed formation mechanism, some requisite conditions for the fabrication of the gold nanoparticle chains were extracted. In this study, the requisite conditions were reproduced in a flow cell using a glass slide with the oriented thin layers of PTFE. By applying temperature gradient to the cell and injecting a colloidal gold solution, a continuous flow was induced in the cell. By this method, the gold nanoparticle chains were successfully formed over the wider area compared to the previous reports. The gold nanoparticle chains were mostly located in the regions where the PTFE thin films were peeled off from the glass substrate. It was suspected that the negatively-charged gold nanoparticles could be electrostatically adsorbed on the glass surface owing to the positive contact charging of the glass slide after the peeling of the PTFE films.

Polytetrafluoroethylene (PTFE) fiber reinforced polyetheretherketone (PEEK) composites

Abstract This work uses high tenacity expanded polytetrafluoroethylene (ePTFE) filaments as both a fiber reinforcement and a reservoir for solid lubricants. The goal is to reduce the wear of the composites by regulating the PTFE transfer. Expanded PTFE films are a porous network of PTFE nodes and fibrils, while highly oriented ePTFE filaments are aligned crystalline fibers that are regarded as high-tenacity fibers that can be woven into threads or yarns. Reported yield strength of these filaments can exceed 500 MPa. The best performing composites were those that had filaments of ePTFE aligned normal to the counterface. The wear rates obtained from the inclusion of expanded PTFE filaments were better than conventional powder filled PTFE–PEEK composites reaching values as low as K = 7 × 10−8 mm3/N m and showed stable friction coefficients below μ = 0.125 for over 2 million cycles.

Charge storage and mechanical properties of porous PTFE and composite PTFE/COC electrets

AbstractRecent futuristic applications of flexible electret loudspeakers have garnered much interest for these novel loudspeakers. To increase the loudspeaker properties, a processing method was developed to improve the electret and mechanical properties of porous PTFE film. Taking a thin porous PTFE film as the base material, a cyclic olefin copolymer (COC) was coated to a base material to form a PTFE/COC composite film. Results show that the composite material improves the advantageous characteristics when used as an electret diaphragm for loudspeakers. By measuring the surface potential decay and the elastic modulus, properties of a standard porous PTFE film were compared to an improved composite PTFE/COC film. Experimental results showed that the composite PTFE/COC possess the following advantages: (1) 80% higher surface potential after 10 days at room temperature, (2) a better thermal resistance of charge storage, and (3) a 643% higher elastic modulus. Therefore, our novel composite material can be used to create a much improved electret diaphragm for flexible electret loudspeakers.