Micro/Nano-Tribological Behavior of Octadecyltrichlorosilane on Silicon as a Coating for MEMS

2005 ◽  
Author(s):  
J. Barriga ◽  
B. Ferna´ndez ◽  
E. Abad ◽  
B. Coto
Keyword(s):  
Liquid Phase ◽  
Vapour Phase ◽  
Stick Slip ◽  
Force Microscopy ◽  
Angle Measurements ◽  
Atomic Force ◽  
Contact Angle Measurements ◽  
Assembled Monolayers ◽  
The Coefficient Of Friction ◽  
Semicontact Mode

Despite progresses achieved in the technology of MEMS, the tribological problem continues being an unresolved matter. Wear and stick-slip phenomena are many times the origin of failure of these devices. The application of self-assembled monolayers (SAMs) in liquid phase seems to be a solution to this problems. SAMs of octadecyltrichlorosilane (CH3(CH2)17SiCl3, OTS) were attached to Si(100) oxidized in liquid phase. Contact angle measurements were used for characterizing the grade of hydrophobicity. The topography of the coating was obtained with an Atomic Force Microscopy (AFM) in semicontact mode. The images showed the presence of particles related to the polymerization of the precursor molecule during the formation process of the SAMs. Creating the film of lubricant in vapour phase would avoid this undesirable effect. Tribological tests were carried out with a microtribometer in linear reciprocating movement with a ball of 2 mm of diameter (100Cr6 and Si3N4) and load of some milinewtons. Results were compared with those obtained for silicon oxidized without any coating. The coefficient of friction (COF) and wear (substrate and ball) were studied under different test conditions.

Wrinkling Poly(trimethylene 2,5-Furanoate) Free-standing Films: Nanostructure Formation and Physical Properties

2020 ◽  
Author(s):  
Michelina Soccio ◽  
Nadia Lotti ◽  
Andrea Munari ◽  
Esther Rebollar ◽  
Daniel E Martínez-Tong
Keyword(s):  
Irradiation Time ◽  
Polymer Surface ◽  
Laser Source ◽  
Free Standing ◽  
Force Microscopy ◽  
Nanostructure Formation ◽  
Physicochemical Changes ◽  
Angle Measurements ◽  
Atomic Force ◽  
Contact Angle Measurements

<p>Nanostructured wrinkles were developed on fully bio-based poly(trimethylene furanoate) (PTF) films by using the technique of Laser Induced Periodic Surface Structures (LIPSS). We investigated the effect of irradiation time on wrinkle formation using an UV pulsed laser source, at a fluence of 8 mJ/cm2. It was found that the pulse range between 600 and 4800 pulses allowed formation of periodic nanometric ripples. The nanostructured surface was studied using a combined macro- and nanoscale approach. We evaluated possible physicochemical changes taking place on the polymer surface after irradiation by infrared spectroscopy, contact angle measurements and atomic force microscopy. The macroscopic physicochemical properties of PTF showed almost no changes after nanostructure formation, differently from the results previously found for the terephthalic counterparts, as poly(ethyleneterephthalate), PET, and poly(trimethyleneterephthalate), PTT. The surface mechanical properties of the nanostructured PTF were found to be improved, as evidenced by nanomechanical force spectroscopy measurements. In particular, an increased Young’s modulus and higher stiffness for the nanostructured sample were measured. <br></p>

scholarly journals Separation of Water/Oil Emulsions by an Electrospun Copolyamide Mat Covered with a 2D Ti3C2Tx MXene

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3171
Author(s):  
AbdolAli Moghaddasi ◽  
Patrik Sobolčiak ◽  
Anton Popelka ◽  
Igor Krupa
Keyword(s):  
Contact Angle ◽  
Vegetable Oil ◽  
Separation Efficiency ◽  
Force Microscopy ◽  
Angle Measurements ◽  
Atomic Force ◽  
Contact Angle Measurements ◽  
Oil Emulsions ◽  
Uv Transmittance ◽  
Stock Solutions

Purpose: Copolyamide 6,10 (coPA) electrospun mats were covered with multilayered (ML) and single-layered (SL) MXene (Ti3C2Tx) as a membrane for the separation of water/vegetable oil emulsions. Methods: Prepared membranes were characterized by atomic force microscopy (AFM), profilometry, the contact angle measurements of various liquids in air, and the underwater contact angle of vegetable oil. The separation efficiency was evaluated by measuring the UV transmittance of stock solutions compared to the UV transmittance of the filtrate. Results: The MXene coating onto coPA mats led to changes in the permeability, hydrophilicity, and roughness of the membranes and enhanced the separation efficiency of the water/vegetable oil emulsions containing 10, 100, and 1000 ppm of sunflower vegetable oil. It was found that membranes were highly oleophobic (>124°) under water, unlike in air, where the membranes showed high oleophobicity (<5°). The separation efficiency of water/oil emulsions for both types of covered membranes reached over 99%, with a surface coverage of 3.2 mg/cm2 Ti3C2Tx (for ML-Ti3C2Tx) and 2.9 mg/cm2 (for SL-Ti3C2Tx). Conclusions: The separation efficiency was greater than 98% for membranes covered with 2.65 mg/cm2 of ML-Ti3C2Tx, whereas the separation efficiency for membranes containing 1.89 and 0.77 mg/cm2 was less than 90% for all studied emulsion concentrations.

Corrosion inhibition behavior of four benzimidazole derivatives and benzotriazole on copper surface

2020 ◽  
Vol 67 (6) ◽  
pp. 565-574
Author(s):  
Lin Liu ◽  
Shuang Lu ◽  
Ya Qi Wu ◽  
Jin Yin Xie ◽  
Jinjuan Xing
Keyword(s):  
Electrochemical Measurement ◽  
Copper Surface ◽  
Molar Ratio ◽  
Benzimidazole Derivatives ◽  
Content Type ◽  
Force Microscopy ◽  
Angle Measurements ◽  
Atomic Force ◽  
Mixture Concentration ◽  
Contact Angle Measurements

Purpose This paper aims to reduce environment pollution caused by benzotriazole. The authors chose one of the best inhibitors from 2-aminobenzimidazole, 2-methylbenzimidazol, 2-mercaptobenzimidazole and benzimidazole in combination with benzotriazole. Design/methodology/approach The electrochemical measurement indicated that 2-methylbenzimidazol had the best inhibition behavior. Then, it was mixed with benzotriazole. Techniques such as field emission scanning electron microscopy, atomic force microscopy, Raman spectroscopy and optical contact angle measurements were used. Findings The results showed that the inhibition efficiency was up to 99.98%, when the mixture concentration was 20 mmol/L and the molar ratio 1:1. Originality/value 1-benzotriazole was mixed with 2-methylbenzimidazol for the first time. During the exist of methyl, 2-methylbenzimidazol has the better inhibition; this point was ignored by researchers. Graphical abstract

Novel vapor phase method for making ultra thin conformal films of polytetrafluoroethylene (PTFE)

2007 ◽  
Vol 992 ◽  
Author(s):  
Sushant Gupta ◽  
Arul Arjunan Chakkaravarthi ◽  
Rajiv Singh ◽  
Jeff Opalko ◽  
Deepika Singh
Keyword(s):  
Chemical Nature ◽  
Phase Method ◽  
Force Microscopy ◽  
Angle Measurements ◽  
Atomic Force ◽  
Contact Angle Measurements ◽  
Pulsed Electron Deposition ◽  
Afm Micrographs ◽  
High Degree ◽  
Deposition Conditions

AbstractUltra-thin conformal polytetrafluoroethylene (PTFE) films were prepared by a novel physical vapor technique i.e., pulsed electron deposition (PED) technique. Prepared PTFE or Teflon thin films show high degree of conformity on patterned substrates. Under optimized deposition conditions the films exhibit superhydrophobicity. The PED processed films were characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM) micrographs and the surface morphology and the conformal nature of the films were studied. The chemical nature and hydrophobicity were studied by FTIR and contact angle measurements, respectively.

PLATING OF COPPER LAYERS ON POLYIMIDES USING ELECTROLESS PLATING BY SURFACE MODIFICATION

2007 ◽  
Vol 14 (04) ◽  
pp. 593-596 ◽  
Author(s):  
EUN SUN JI ◽  
YOUNG HWAN KIM ◽  
YONG CHEOL KANG ◽  
YOUNG SOO KANG ◽  
BYUNG HYUN AHN
Keyword(s):  
Electroless Plating ◽  
Electroless Deposition ◽  
Solution Treatment ◽  
Polyimide Films ◽  
Force Microscopy ◽  
Angle Measurements ◽  
Atomic Force ◽  
Plating Method ◽  
Contact Angle Measurements ◽  
Activated Surface

This work describes electroless deposition of copper layers onto a polyimide (PI) film. The film was modified by etching with 1.0 M KOH solution treatment, and an activated Ag thin film was developed on this surface using 0.1 M AgNO 3. The Cu layers were coated on the activated surface of polyimide films by electroless plating method. The thickness and surface morphology of Cu layers on the PI films were characterized with atomic force microscopy. The surface properties of PI film were identified with contact angle measurements.

Improvement of Hydrophilic Stability of Diamond-Like Carbon Films by O2/CF4 Plasma Post-Treatment

2015 ◽  
Vol 1125 ◽  
pp. 38-44
Author(s):  
Chavin Jongwannasiri ◽  
Shuichi Watanabe
Keyword(s):  
Carbon Films ◽  
Post Treatment ◽  
Attenuated Total Reflectance ◽  
Diamond Like Carbon ◽  
Total Reflectance ◽  
Force Microscopy ◽  
Angle Measurements ◽  
Atomic Force ◽  
Contact Angle Measurements ◽  
Before And After

In this article, the results obtained from a study carried out on the plasma post-treatment of diamond-like carbon (DLC) films using an oxygen/tetrafluoromethane (O2/CF4) gas mixture is reported. The surface morphology and chemical bonding of the films before and after the plasma post-treatment were characterized using atomic force microscopy (AFM) and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy. The effect of adding CF4 to the O2 plasma on the wettability of the films was also examined using contact angle measurements. The results indicate that the surface roughness increased with the addition of CF4 to the O2 plasma, whereas oxygen-and fluorinated-based functional groups were generated on the surface of the DLC films submitted to O2/CF4 plasma post-treatment. The surface energy also decreased with increasing CF4 fraction, causing the surface of the films to be hydrophobic. Furthermore, the films containing 20% CF4 exhibited higher hydrophilic stability than the others. Thus, the addition of a small amount of CF4 to O2 plasma can be considered beneficial in improving the hydrophilic stability of surface of DLC films.

Biopolymer Blends as Potential Biomaterials and Cosmetic Materials

2013 ◽  
Vol 583 ◽  
pp. 95-100 ◽  
Author(s):  
Alina Sionkowska ◽  
Katarzyna Lewandowska ◽  
A. Planecka ◽  
P. Szarszewska ◽  
K. Krasinska ◽  
...  
Keyword(s):  
Contact Angle ◽  
Free Energy ◽  
Surface Free Energy ◽  
Silk Fibroin ◽  
High Surface ◽  
Force Microscopy ◽  
Angle Measurements ◽  
Atomic Force ◽  
Polymeric Blends ◽  
Contact Angle Measurements

Blends of two polymer, namely chitosan with silk fibroin or partially hydrolysed polyacrylamide (HPAM) were prepared. The surface properties of chitosan/silk fibroin and chitosan/HPAM blended films were investigated using the technique of Atomic Force Microscopy (AFM) and by means of contact angle measurements allowing the calculation of surface free energy. Measurements of the contact angle for diiodomethane (D), and glycerol (G) on the surface of chitosan films and chitosan/silk fibroin films were made and surface free energy was calculated. It was found that chitosan/silk fibroin blend surface is enriched in high surface energy component i.e. silk fibroin. The surface roughness of chitosan, silk fibroin, HPAM, chitosan/silk fibroin and chitosan/HPAM blended films differs with the composition of the blend. Film-forming polymeric blends can be potentially used as biomaterials and cosmetic materials.

Surface characterization of polymer foils

e-Polymers ◽  
2012 ◽  
Vol 12 (1) ◽  
Author(s):  
Zdenka Kolská ◽  
Alena Řezníčková ◽  
Václav Švorčík
Keyword(s):  
Zeta Potential ◽  
Surface Characterization ◽  
Streaming Potential ◽  
Electrolyte Solutions ◽  
Force Microscopy ◽  
Angle Measurements ◽  
Atomic Force ◽  
Contact Angle Measurements ◽  
Polymer Foils

AbstractElectrokinetic potential (zeta potential) for selected 21 polymer foils was studied. The results on zeta potential are supplemented with contact angle measurements (goniometry) and with the results on surface roughness measured by atomic force microscopy (AFM). Zeta potential was determined using two approaches: streaming current and streaming potential at pH=6.0-6.2. Two electrolyte solutions with KCl (concentrations 0.001 and 0.005 mol/dm3) and KNO3 (0.001 mol/dm3) were used in the experiments. Zeta potential was shown to depend on surface chemistry, polarity, roughness and morphology of the polymer foils.

scholarly journals Dynamic Cell Surface Hydrophobicity of Lactobacillus Strains with and without Surface Layer Proteins

2004 ◽  
Vol 186 (19) ◽  
pp. 6647-6650 ◽  
Author(s):  
Virginia Vadillo-Rodríguez ◽  
Henk J. Busscher ◽  
Willem Norde ◽  
Joop de Vries ◽  
Henny C. van der Mei
Keyword(s):  
Ionic Strength ◽  
Cell Surface ◽  
Cell Surface Hydrophobicity ◽  
Interaction Force ◽  
Surface Hydrophobicity ◽  
Force Microscopy ◽  
Angle Measurements ◽  
Atomic Force ◽  
Contact Angle Measurements ◽  
Dynamic Cell

ABSTRACT Variations in surface hydrophobicity of six Lactobacillus strains with and without an S-layer upon changes in ionic strength are derived from contact angle measurements with low- and high-ionic-strength aqueous solutions. Cell surface hydrophobicity changed in response to changes in ionic strength in three out of the six strains, offering these strains a versatile mechanism to adhere to different surfaces. The dynamic behavior of the cell surface hydrophobicity could be confirmed for two selected strains by measuring the interaction force between hydrophobic and hydrophilic tips with use of atomic force microscopy.

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