Novel One-Component Anisole- and Hydroxyl-Terminated Perfluoropolyethers for Boundary Lubrication

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Ao Fan ◽  
Connie Wiita ◽  
Robert J. Waltman
Keyword(s):  
Film Thickness ◽  
Single Component ◽  
Hydroxyl Groups ◽  
Film Properties ◽  
Lubricant Transfer ◽  
Boundary Lubricant ◽  
Boundary Film ◽  
End Groups ◽  
Boundary Lubricants ◽  
Physical Mixtures

The tribological properties of some novel single component perfluoropolyether (PFPE) boundary lubricants with chemically integrated mixture end groups are investigated. Chemically integrated mixture end groups composed of hydroxyl- and anisole-terminated PFPE boundary lubricant films on the –(CF2CF2CF2O)– main chain are reported. These PFPE-based boundary lubricants explore a new method by which single component PFPE lubricants with mixture end groups might be used to tailor boundary film properties instead of using physical mixtures of two or more PFPEs with different end groups. Lubricant transfer to the low-flying read/write head, head wear, and siloxane adsorption as a function of PFPE film thickness and of type are compared. Normalization of the data to the monolayer fraction instead of film thickness allows direct comparison between anisole- and hydroxyl-terminated PFPEs. Lubricant transfer to the head and head wear are independent of the functional end groups. Siloxane adsorption decreases with increasing anisole substitution of the hydroxyl groups. One-component PFPEs with mixed end groups provide a methodology by which boundary film properties could be adjusted.

Quantification of the Surface Morphology of Lubricant Films With Polar End Groups Using Molecular Dynamics Simulation: Periodic Changes in Morphology Depending on Film Thickness

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Susumu Ogata ◽  
Hedong Zhang ◽  
Kenji Fukuzawa ◽  
Yasunaga Mitsuya
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Surface Morphology ◽  
Film Thickness ◽  
Film Surface ◽  
Dynamics Simulation ◽  
Molecular Probe ◽  
Coarse Grained ◽  
End Groups ◽  
Lubricant Films

Using a coarse-grained molecular dynamics simulation based on the bead-spring polymer model, we reproduced the film distribution of molecularly thin lubricant films with polar end groups coated on the disk surface and quantified the film-surface morphology using a molecular-probe scanning method. We found that the film-surface morphology changed periodically with increasing film thickness. The monolayer of a polar lubricant that entirely covers the solid surface provides a flat lubricant surface by exposing its nonpolar backbone outside of the monolayer. By increasing film thickness, the end beads aggregate to make clusters, and bulges form on the lubricant surface, accompanying an increase in surface roughness. The bulges continue to grow even though the averaged film thickness reaches or exceeds the bilayer thickness. With further increases in film thickness, the clusters start to be uniformly distributed in the lateral direction to clearly form a third layer. As for the formation of fourth and fifth layers, the process is basically the same as that for the second and third layers. Through our calculations of the intermolecular potential field and the intermolecular force field, these values are found to change periodically and are synchronized with the formation of molecule aggregations, which explains the mechanism of forming the layered structure that is inherent to a polar lubricant.

scholarly journals The Formation of Glycerol Oligomers with Two New Types of End Groups in the Presence of a Homogeneous Alkaline Catalyst

Polymers ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 144 ◽  
Author(s):  
Dawid Kansy ◽  
Kornelia Bosowska ◽  
Krystyna Czaja ◽  
Anna Poliwoda
Keyword(s):  
Catalyst Concentration ◽  
Reaction Medium ◽  
Hydroxyl Groups ◽  
Ionization Mass ◽  
Carboxylate Group ◽  
Reaction Products ◽  
Direct Infusion ◽  
Alkaline Catalyst ◽  
End Groups ◽  
First Time

The purpose of this work was to synthesize and characterize oligoglycerols with the chains of more than four repeating units. Those oligoglycerols may have some interesting applications, among others, as polyoxyalkylation starters. The glycerol oligomerization process was carried out during 12 h, at 230 °C, under the pressure of 0.4 bar, with the use of sodium carbonate as a homogeneous basic catalyst; various concentrations of the catalyst in the reaction medium were used. The reaction products were analyzed with the use of direct infusion electrospray ionization mass spectrometry (ESI-MS), nuclear magnetic resonance (13C NMR) and Fourier transform infrared spectroscopy (FTIR) techniques. Based on the analytical findings, the compositions of the obtained product mixtures and the structures of oligoglycerols present in individual fractions were determined. The effect of catalyst concentration on the composition of the post-reaction mixture was observed. Moreover, in addition to the conventional linear oligomers (α,α-oligoglycerols), two new types of the oligomers were for the first time detected in the post-reaction mixture: one with two hydroxyl groups and the other with a carboxylate group at the α-carbon atom.

Synthesis and Characterization of Carboxyl-Terminated Hyperbranched Polyester

2014 ◽  
Vol 665 ◽  
pp. 327-330
Author(s):  
Shi Jie Niu ◽  
Jian Wang ◽  
Yu Qing Bai ◽  
Ming Tao Run
Keyword(s):  
Glass Transition ◽  
Sodium Acetate ◽  
Succinic Anhydride ◽  
Molar Ratio ◽  
Synthesis And Characterization ◽  
Hydroxyl Groups ◽  
Hyperbranched Polyester ◽  
End Groups ◽  
Lower Glass Transition Temperature

In order to prepare carboxyl-terminated hyperbranched polyester (HBP-COOH), succinic anhydride was used to modify hydroxyl-terminated hyperbranched polyester (HBP-OH), and the influences of the solvents, catalysts and time on the product’s structure were investigated. When THF is used as the solvent, sodium acetate as the catalyst, the molar ratio of succinic anhydride and hydroxyl groups is 3:1, and the reaction time is 6 h at 65°C, the modification extent of the hydroxyl groups is about 99% with about 95% yield. HBP-COOH has much lower glass transition temperature than that of HBP-OH due to its long and flexible end-groups.

Spreading of Novel Cyclotriphosphazine-Terminated PFPE Films on Carbon Surfaces

2004 ◽  
Vol 126 (4) ◽  
pp. 751-754 ◽  
Author(s):  
Norio Tagawa ◽  
Tadao Tateyama ◽  
Atsunobu Mori ◽  
Nagayoshi Kobayashi ◽  
Yoshinobu Fujii ◽  
...  
Keyword(s):  
Film Thickness ◽  
Diffusion Coefficients ◽  
Work Of Adhesion ◽  
Monolayer Film ◽  
Apparent Diffusion Coefficients ◽  
End Groups ◽  
Lubricant Films ◽  
Apparent Diffusion ◽  
Matano Interface ◽  
Carbon Surfaces

Spreading characteristics of novel cyclotriphosphazine-terminated Perfluoropolyether (PFPE) films on carbon surfaces were investigated experimentally by using a scanning micro-ellipsometer. The apparent diffusion coefficients of novel lubricants were also studied in order to evaluate the spreading speed and they were compared with the conventional Zdol. It was found that the mobility of cyclotriphosphazine-terminated PFPE films is lower than that of Zdol. This characteristics is dependent on the interactions between the end groups of the lubricants and carbon surfaces and it is found that the tendency of “work of adhesion” for the lubricants has a good correlation with the mobility tendency of the lubricants. In addition, the monolayer film thickness of novel lubricant films as well as conventional Zdol was identified, which was extracted using Matano interface method. As a result, the existing conformation of novel cyclotriphosphazine-terminated PFPE film on carbon surfaces could be estimated, based on the monolayer film thickness results.

The Effect of Post-Growth Anneals on Nitroxide Films

1989 ◽  
Vol 146 ◽  
Author(s):  
Peter J. Wright ◽  
Ahmad Kermani ◽  
Krishna C. Saraswat
Keyword(s):  
Film Thickness ◽  
Electron Mobility ◽  
Gate Dielectrics ◽  
Electron Lifetime ◽  
Hot Electron ◽  
Film Properties ◽  
Interface Quality ◽  
A New Technique ◽  
Mos Gate

ABSTRACTA new technique of post-oxidation annealing has been introduced to improve the properties and long term reliability of ultrathin (<100 Å) MOS gate dielectrics. In this technique, after oxidation, nitridation is done in NH3 followed by a light reoxidation in O2 and then an inert anneal in Ar or N2. Using this technique both optimum performance as well as reliability can be obtained without sacrificing either. NH3 anneal of SiO2 improved the hot electron immunity, but degraded the interface quality. Good properties could be obtained by a strong reoxidation of the nitrided films, however, at the expense of a substantial increase in the film thickness. Nitrogen and argon ambients were found to be equally effective at improving film properties. By annealing the film in an inert ambient following reoxidation of the nitroxide, fixed charge can be further decreased with little oxide grown, electron mobility in NMOS FETs increases further, and the hot electron lifetime is much longer than that of the starting oxide.

scholarly journals Infrared Sensor For CVD Deposition Of Dielectric Films

1994 ◽  
Vol 341 ◽  
Author(s):  
Thomas M. Niemczyk ◽  
James E. Franke ◽  
Songbiao Zhang ◽  
David M. Haaland
Keyword(s):  
Thin Film ◽  
Film Thickness ◽  
Phosphorus Content ◽  
Infrared Emission ◽  
Dielectric Films ◽  
Standard Errors ◽  
Film Sample ◽  
Film Properties ◽  
P Content ◽  
Borophosphosilicate Glass

AbstractInfrared emission (IRE) spectra were obtained from two borophosphosilicate glass (BPSG) thin-film sample sets. The first set consisted of 21 films deposited on undoped silicon wafers, and the second set consisted of 9 films deposited on patterned and doped (product) wafers. The IRE data were empirically modeled using partial least-squares calibration to simultaneously quantify four BPSG thin-film properties. The standard errors of the determinations when modeling the 21 monitor wafers were < 0.1 wt% for boron and phosphorus content, 36 Å for film thickness, and 1.9°C for temperature. The standard errors of the determinations based on the product wafers were 0.13 wt% each for B and P content, 120 Å for film thickness, and 5.9°C for temperature.

Orientation Selection in Sol-Gel Derived PZT Thin Films

2000 ◽  
Vol 655 ◽  
Author(s):  
G. J. Norga ◽  
Laura Fé
Keyword(s):  
Film Thickness ◽  
Sol Gel ◽  
Electrode System ◽  
Film Properties ◽  
Orientation Selection ◽  
Pzt Film ◽  
Pzt Films ◽  
Basic Studies ◽  
Excessive Oxygen ◽  
Real Temperature

AbstractMotivated by the growing impact of PZT film orientation on ferroelectric film properties as film thickness is scaled down, we present basic studies on orientation selection in sol-gel derived PZT films, using pre-annealed Pt/Ti electrode layers as a model electrode system. FTIR was used to study, on a real temperature scale, chemical reactions in the films during the initial thermal steps prior to crystallization. We found that the chemical structure of the pyrolyzed film has a much larger impact on orientation selection than has previously been realized. In addition to pyrolysis conditions, the ambient used for the crystallization step was found to play a crucial role in orientation selection. As film thickness decreases, excessive oxygen incorporation in the films is seen to result in the loss of the preferential (111) texture when crystallization is performed in air. By performing crystallizations in N2, 40 nm thick PZT films with a strongly preferential (111) orientation could be obtained.

scholarly journals The Assessment of Friction Process of Model Kinematic Pair Worked under DC Voltage / Ocena Procesu Tarcia W Modelowym Weźle Kinematycznym Pracującym Pod Napięciem Elektrycznym

2014 ◽  
Vol 31 (1) ◽  
pp. 84-91
Author(s):  
Emil Nowiński ◽  
Jarosław Sarnecki
Keyword(s):  
Film Thickness ◽  
Electric Current ◽  
Current Flow ◽  
Kinematic Pair ◽  
Friction Process ◽  
Dc Voltage ◽  
Friction Resistance ◽  
Boundary Film ◽  
The Subject ◽  
Electrical Motors

Abstract The subject of this paper is assessment of friction process of model kinetic pair worked under DC voltage. The friction under this conditions may take place in case of triboelectrical phenomena and in friction pairs of electrical motors. The significant influence of electric current flow on friction resistance and boundary film thickness was presented. Results of the research were compared to the results of research under load and without electric current applied.

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