Effects of adsorbed water layer structure on adhesion force of silicon oxide nanoasperity contact in humid ambient

2006 ◽  
Vol 124 (17) ◽  
pp. 174712 ◽  
Author(s):  
David B. Asay ◽  
Seong H. Kim
Keyword(s):  
Silicon Oxide ◽  
Adhesion Force ◽  
Layer Structure ◽  
Water Layer ◽  
Adsorbed Water

scholarly journals Effect of Humidity on Friction and Wear—A Critical Review

Lubricants ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 74 ◽  
Author(s):  
Zhe Chen ◽  
Xin He ◽  
Chen Xiao ◽  
Seong Kim
Keyword(s):  
Friction And Wear ◽  
Silicon Oxide ◽  
Wear Behavior ◽  
Hexagonal Boron Nitride ◽  
Transition Metal Dichalcogenides ◽  
Water Layer ◽  
Adsorbed Water ◽  
Ambient Air ◽  
Ultrananocrystalline Diamond ◽  
Defect Sites

The friction and wear behavior of materials are not intrinsic properties, but extrinsic properties; in other words, they can drastically vary depending on test and environmental conditions. In ambient air, humidity is one such extrinsic parameter. This paper reviews the effects of humidity on macro- and nano-scale friction and wear of various types of materials. The materials included in this review are graphite and graphene, diamond-like carbon (DLC) films, ultrananocrystalline diamond (UNCD), transition metal dichalcogenides (TMDs), hexagonal boron nitride (h-BN), boric acid, silicon, silicon oxide, silicates, advanced ceramics, and metals. Details of underlying mechanisms governing friction and wear behaviors vary depending on materials and humidity; nonetheless, a comparison of various material cases revealed an overarching trend. Tribochemical reactions between the tribo-materials and the adsorbed water molecules play significant roles; such reactions can occur at defect sites in the case of two-dimensionally layered materials and carbon-based materials, or even on low energy surfaces in the case of metals and oxide materials. It is extremely important to consider the effects of adsorbed water layer thickness and structure for a full understanding of tribological properties of materials in ambient air.

Restricted Rotational Motion of InterlayerWaterMolecules in Vanadium Pentoxide Hydrate, V2O5·n D2O, as Studied by Deuterium NMR

2002 ◽  
Vol 57 (6-7) ◽  
pp. 419-424 ◽  
Author(s):  
Sadamu Takeda ◽  
Yuko Gotoh ◽  
Goro Maruta ◽  
Shuichi Takahara ◽  
Shigeharu Kittaka
Keyword(s):  
Double Layer ◽  
Vanadium Pentoxide ◽  
Rotational Motion ◽  
Interlayer Space ◽  
Layer Structure ◽  
Bond Distance ◽  
Adsorbed Water ◽  
Deuterium Nmr ◽  
Water Molecules ◽  
Layer Structures

The rotational behavior of the interlayer water molecules of deuterated vanadium pentoxide hydrate, V2O5.nD2O, was studied by solid-state deuterium NMR for the mono- and double-layer structures of the adsorbed water molecules. The rotational motion was anisotropic even at 355 K for both the mono- and double-layer structures. The 180° flipping motion about the C2-symmetry axis of the water molecule and the rotation around the figure axis, which makes an angle Ɵ with the C2-axis, occurred with the activation energy of (34±4) and (49±6) kJmol-1, respectively. The activation energies were almost independent of the mono- and double-layer structures of the water molecules, but the angle Ɵ made by the two axes varied from 33° for the monolayer to 25° for the double-layer at 230 K. The angle started to decrease above 250 K (e. g. the angle was 17 at 355 K for the double-layer structure). The results indicate that the average orientation of the water molecules in the two dimensional interlayer space depends on the layer structure and on the temperature. From the deuterium NMR spectrum at 130 K, the quadrupole coupling constant e2Qq/h = 240 kHz and the asymmetry parameter η= 0.12 were deduced. These values indicate the average hydrogen bond distance R(O H) = 2.0 Å for the D2O molecules in the 2D-interlayer space

scholarly journals Mechanics for the Adhesion and Aggregation of Red Blood Cells on Chitosan

2018 ◽  
Vol 34 (5) ◽  
pp. 725-732 ◽  
Author(s):  
K. Y. Chen ◽  
T. H. Lin ◽  
C. Y. Yang ◽  
Y. W. Kuo ◽  
U. Lei
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Biomedical Applications ◽  
Adhesion Force ◽  
Layer Structure ◽  
Optical Tweezer ◽  
Wound Dressings ◽  
Zeta Potentials ◽  
Rbc Membrane ◽  
Layer Structures

AbstractHemostasis, a process which causes bleeding to stop, can be enhanced using chitosan; but the detailed mechanism is unclear. Red blood cells (RBCs) adhere to chitosan because of their opposite charges, but the adhesion force is small, 3.83 pN as measured here using an optical tweezer, such that the direct adhesion cannot be the sole cause for hemostasis. However, it was observed in this study that layer structures of aggregated RBCs were formed next to chitosan objects in both static and flowing environments, but not formed next to cotton and rayon yarns. The layer structure is the clue for the initiation of hemostatsis. Through the supporting measurements of zeta potentials of RBCs and pH's using blood-chitosan mixtures, it is proposed here that the formation of the RBC layer structure next to chitosan objects is due to the reduction of repulsive electric double layer force between RBCs, because of the association of H+ deprotonated from chitosan with COO− on RBC membrane, under the DLVO (Derjaguin-Landau-Verwey-Overbeek) theory. The results are beneficial for designing effective chitosan-based wound dressings, and also for general biomedical applications.

Effective performance improvement of organic thin film transistors by using tri-layer insulators

2018 ◽  
Vol 83 (2) ◽  
pp. 20201 ◽  
Author(s):  
Yao Ni ◽  
Jianlin Zhou ◽  
Yuanyuan Hao ◽  
Hang Yu ◽  
Yanyun Li ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Film Transistors ◽  
Silicon Oxide ◽  
Layer Structure ◽  
Organic Thin Film Transistors ◽  
Organic Thin Film ◽  
Interface Quality ◽  
Organic Semiconductor Materials ◽  
Effective Performance ◽  
P Type

Organic thin film transistors (OTFTs) with silicon oxide (SiO2)/poly(4-vinylphenol) (PVP)/polymethylmethacrylate (PMMA) tri-layer structure (SPP) as dielectric layers have been fabricated. To verify the validity of such tri-layer structure, two different organic semiconductor materials such as p-type pentacene and n-type fluorinated copper phthalo–cyanine (F16CuPc) are both used for fabricating OTFTs. Comparing with the OTFTs even by using PMMA modification, the better interface quality existing between SPP dielectric and organic film leads a higher conductive efficiency for transport carriers in channel. And then the field effect carriers (hole in pentacene OTFTs and electron in F16CuPc OTFTs) mobilities are both increased obviously. Our results show the SPP dielectric structure can be widely used to improve performance of OTFTs.

First Adsorbed Water Layer and Its Wettability Transition under Compressive Lattice Strain

2019 ◽  
Vol 124 (7) ◽  
pp. 4057-4064
Author(s):  
Guobing Zhou ◽  
Bradley H. Schoen ◽  
Zhen Yang ◽  
Liangliang Huang
Keyword(s):  
Lattice Strain ◽  
Water Layer ◽  
Adsorbed Water

scholarly journals Effects of Gas Adsorption in Nanotribology and Demonstration of In-Situ Vapor Phase Lubrication of MEMS Devices

2007 ◽  
Author(s):  
David B. Asay ◽  
Michael T. Dugger ◽  
Seong H. Kim
Keyword(s):  
Vapor Phase ◽  
Microelectromechanical Systems ◽  
Silicon Oxide ◽  
Gas Adsorption ◽  
Extended Period ◽  
Adsorbed Water ◽  
Oxide Surface ◽  
Mems Devices ◽  
Vapor Phase Lubrication

This paper discusses the important role of gas adsorption in nanotribology and demonstrates in-situ vapor phase lubrication of microelectromechanical systems (MEMS) devices. We have elucidated the molecular ordering and thickness of the adsorbed water layer on the clean silicon oxide surface and found the molecular-level origin for the high adhesion between nano-asperity silicon oxide contacts in humid ambient. The same gas adsorption process can be utilized for continuous supply of lubricant molecules to form a few Å thick lubricant films on solid surfaces. Using alcohol vapor adsorption, we demonstrated that the adhesion, friction, and wear of the silicon oxide surface can significantly be reduced. This process made it possible to operate sliding MEMS without failure for an extended period of time.

scholarly journals Quantitative Estimation of Adsorbed Water Layer on Austenitic Stainless Steel

2015 ◽  
Vol 10 (5) ◽  
pp. 314-319 ◽  
Author(s):  
Zaid Ali Subhi ◽  
Kanao Fukuda ◽  
Takehiro Morita ◽  
Joichi Sugimura
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Quantitative Estimation ◽  
Water Layer ◽  
Adsorbed Water
Sign in / Sign up

Export Citation Format

Share Document