scholarly journals Anomalous Interfacial Structuring of a Non-Halogenated Ionic Liquid: Effect of Substrate and Temperature

2018 ◽  
Vol 2 (4) ◽  
pp. 60 ◽  
Author(s):  
Milad Radiom ◽  
Patricia Pedraz ◽  
Georgia Pilkington ◽  
Patrick Rohlmann ◽  
Sergei Glavatskih ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Surface Charge ◽  
Force Measurement ◽  
Surface Force ◽  
Solid Surfaces ◽  
Effect Of Temperature ◽  
Decay Length ◽  
Force Microscopy ◽  
Large Size ◽  
Atomic Force

We investigate the interfacial properties of the non-halogenated ionic liquid (IL), trihexyl(tetradecyl)phosphonium bis(mandelato)borate, [P6,6,6,14][BMB], in proximity to solid surfaces, by means of surface force measurement. The system consists of sharp atomic force microscopy (AFM) tips interacting with solid surfaces of mica, silica, and gold. We find that the force response has a monotonic form, from which a characteristic steric decay length can be extracted. The decay length is comparable with the size of the ions, suggesting that a layer is formed on the surface, but that it is diffuse. The long alkyl chains of the cation, the large size of the anion, as well as crowding of the cations at the surface of negatively charged mica, are all factors which are likely to oppose the interfacial stratification which has, hitherto, been considered a characteristic of ionic liquids. The variation in the decay length also reveals differences in the layer composition at different surfaces, which can be related to their surface charge. This, in turn, allows the conclusion that silica has a low surface charge in this aprotic ionic liquid. Furthermore, the effect of temperature has been investigated. Elevating the temperature to 40 °C causes negligible changes in the interaction. At 80 °C and 120 °C, we observe a layering artefact which precludes further analysis, and we present the underlying instrumental origin of this rather universal artefact.

scholarly journals Is the boundary layer of an ionic liquid equally lubricating at higher temperature?

2016 ◽  
Vol 18 (13) ◽  
pp. 9232-9239 ◽  
Author(s):  
Nicklas Hjalmarsson ◽  
Rob Atkin ◽  
Mark W. Rutland
Keyword(s):  
Ionic Liquid ◽  
Room Temperature ◽  
Effect Of Temperature ◽  
Force Microscopy ◽  
Normal Forces ◽  
Silica Colloid ◽  
Atomic Force ◽  
Ethylammonium Nitrate ◽  
Higher Temperature ◽  
C 50

Atomic force microscopy has been used to study the effect of temperature on normal forces and friction for the room temperature ionic liquid (IL) ethylammonium nitrate (EAN), confined between mica and a silica colloid probe at 25 °C, 50 °C, and 80 °C.

Surface charge mapping of solid surfaces in water by pulsed-force-mode atomic force microscopy

1998 ◽  
Vol 66 (7) ◽  
pp. S349-S352 ◽  
Author(s):  
T. Miyatani ◽  
S. Okamoto ◽  
A. Rosa ◽  
O. Marti ◽  
M. Fujihira
Keyword(s):  
Atomic Force Microscopy ◽  
Surface Charge ◽  
Solid Surfaces ◽  
Force Microscopy ◽  
Atomic Force ◽  
Force Mode ◽  
Mode Atomic Force Microscopy

scholarly journals Study on the Quantitative Evaluation of the Surface Force Using a Scanning Probe Microscope

Lubricants ◽  
2020 ◽  
Vol 8 (6) ◽  
pp. 66
Author(s):  
Wataru Yagi ◽  
Tomomi Honda ◽  
Kazushi Tamura ◽  
Keiichi Narita
Keyword(s):  
Force Measurement ◽  
Electrostatic Force ◽  
Surface Force ◽  
Calibration Method ◽  
Interaction Force ◽  
Polar Group ◽  
Force Microscopy ◽  
Fluid Resistance ◽  
Atomic Force ◽  
Probe Microscope

There are two types of friction modifiers (FMs) used as lubricant additives: Reaction film FMs (RF-FMs) and adsorption film FMs (AF-FMs). While RF-FMs provide good performance in severe conditions, AF-FMs excel in mild conditions. This empirical evidence leads us to combine these two FMs to cover broader conditions. However, the effects of their combination are highly complicated due to the interaction between these FMs. If the interaction force of AF-FMs with various materials can be evaluated, it would help us to improve tribological performances of lubricants. Although atomic force microscopy seems suitable for this application, we found some obstacles, such as fluid resistance, electrostatic force, and laser positioning of the cantilever, to achieve proper measurements of the adsorption force. In this study, the adsorption force between the polar group and the surface was directly measured in oil with a 1 µm silica probe modified with CH3 or COOH. This paper proposed how to eliminate errors included in the adsorption force measurement using AFM and a calibration method for obtaining an accurate adsorption force of the polar group, and a test of normality of the measured data was conducted by 400 measurements. As a result, it was shown that approximately 100 tests were needed to obtain an accurate adsorption force in this study.

scholarly journals Effect of water on the electroresponsive structuring and friction in dilute and concentrated ionic liquid lubricant mixtures

2020 ◽  
Vol 22 (48) ◽  
pp. 28191-28201
Author(s):  
Georgia A. Pilkington ◽  
Rebecca Welbourn ◽  
Anna Oleshkevych ◽  
Seiya Watanabe ◽  
Patricia Pedraz ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Ionic Liquid ◽  
Neutron Reflectivity ◽  
Force Microscopy ◽  
Liquid Lubricant ◽  
Effect Of Water ◽  
Atomic Force ◽  
Ambient Levels

The influence of ambient levels of water on the electroresponsive interfacial structuring and nanofriction of ionic liquid lubricant mixtures has been investigated by neutron reflectivity and atomic force microscopy.

scholarly journals Movements of Mycoplasma mobile gliding machinery detected by high-speed atomic force microscopy

2021 ◽  
Author(s):  
Kohei Kobayashi ◽  
Noriyuki Kodera ◽  
Taishi Kasai ◽  
Yuhei O Tahara ◽  
Takuma Toyonaga ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Internal Structure ◽  
Sodium Azide ◽  
High Speed ◽  
Atp Hydrolysis ◽  
Solid Surfaces ◽  
Force Microscopy ◽  
Special Mechanism ◽  
Atomic Force ◽  
Internal Structures

ABSTRACTMycoplasma mobile, a parasitic bacterium, glides on solid surfaces, such as animal cells and glass by a special mechanism. This process is driven by the force generated through ATP hydrolysis on an internal structure. However, the spatial and temporal behaviors of the internal structures in living cells are unclear. In this study, we detected the movements of the internal structure by scanning cells immobilized on a glass substrate using high-speed atomic force microscopy (HS-AFM). By scanning the surface of a cell, we succeeded in visualizing particles, 2 nm in hight and aligned mostly along the cell axis with a pitch of 31.5 nm, consistent with previously reported features based on electron microscopy. Movements of individual particles were then analyzed by HS-AFM. In the presence of sodium azide, the average speed of particle movements was reduced, suggesting that movement is linked to ATP hydrolysis. Partial inhibition of the reaction by sodium azide enabled us to analyze particle behavior in detail, showing that the particles move 9 nm right, relative to the gliding direction, and 2 nm into the cell interior in 330 ms, then return to their original position, based on ATP hydrolysis.IMPORTANCEThe Mycoplasma genus contains bacteria generally parasitic to animals and plants. Some Mycoplasma species form a protrusion at a pole, bind to solid surfaces, and glide by a special mechanism linked to their infection and survival. The special machinery for gliding can be divided into surface and internal structures that have evolved from rotary motors represented by ATP synthases. This study succeeded in visualizing the real-time movements of the internal structure by scanning from the outside of the cell using an innovative high-speed atomic force microscope, and then analyzing their behaviors.

A study of molecular adsorption of a cationic surfactant on complex surfaces with atomic force microscopy

The Analyst ◽  
2016 ◽  
Vol 141 (3) ◽  
pp. 1017-1026 ◽  
Author(s):  
I. Sokolov ◽  
G. Zorn ◽  
J. M. Nichols
Keyword(s):  
Atomic Force Microscopy ◽  
Cationic Surfactant ◽  
Solid Surfaces ◽  
Molecular Adsorption ◽  
Complex Surfaces ◽  
Force Microscopy ◽  
Atomic Force ◽  
Broad Interest

The study of molecular adsorption on solid surfaces is of broad interest.

scholarly journals Electroresponsive structuring and friction of a non-halogenated ionic liquid in a polar solvent: effect of concentration

2020 ◽  
Vol 22 (34) ◽  
pp. 19162-19171 ◽  
Author(s):  
Georgia A. Pilkington ◽  
Anna Oleshkevych ◽  
Patricia Pedraz ◽  
Seiya Watanabe ◽  
Milad Radiom ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Ionic Liquid ◽  
Solvent Effect ◽  
Polar Solvent ◽  
Neutron Reflectivity ◽  
Force Microscopy ◽  
Frictional Properties ◽  
Atomic Force

Neutron reflectivity and atomic force microscopy results reveal the electroresponsive interfacial structuring and nano-frictional properties of ionic liquid (IL) lubricant mixtures with a polar solvent are strongly dependent on bulk IL concentration.

scholarly journals The Elastic Properties of the Caulobacter crescentus Adhesive Holdfast Are Dependent on Oligomers of N-Acetylglucosamine

2005 ◽  
Vol 187 (1) ◽  
pp. 257-265 ◽  
Author(s):  
Guanglai Li ◽  
Christopher S. Smith ◽  
Yves V. Brun ◽  
Jay X. Tang
Keyword(s):  
Force Constant ◽  
Elastic Properties ◽  
Caulobacter Crescentus ◽  
Theoretical Estimate ◽  
Solid Surfaces ◽  
Force Microscopy ◽  
Atomic Force ◽  
Microscopy Analysis ◽  
Rigid Rod ◽  
Stalk Length

ABSTRACT The aquatic bacterium Caulobacter crescentus attaches to solid surfaces through an adhesive holdfast located at the tip of its polar stalk, a thin cylindrical extension of the cell membrane. In this paper, the elastic properties of the C. crescentus stalk and holdfast assembly were studied by using video light microscopy. In particular, the contribution of oligomers of N-acetylglucosamine (GlcNAc) to the elasticity of holdfast was examined by lysozyme digestion. C. crescentus cells attached to a surface undergo Brownian motion while confined effectively in a harmonic potential. Mathematical analysis of such motion enabled us to determine the force constant of the stalk-holdfast assembly, which quantifies its elastic properties. The measured force constant exhibits no dependence on stalk length, consistent with the theoretical estimate showing that the stalk can be treated as a rigid rod with respect to fluctuations of the attached cells. Therefore, the force constant of the stalk-holdfast assembly can be attributed to the elasticity of the holdfast. Motions of cells in a rosette were found to be correlated, consistent with the elastic characteristics of the holdfast. Atomic force microscopy analysis indicates that the height of a dried (in air) holdfast is approximately one-third of that of a wet (in water) holdfast, consistent with the gel-like nature of the holdfast. Lysozyme, which cleaves oligomers of GlcNAc, reduced the force constant to less than 10% of its original value, consistent with the polysaccharide gel-like nature of the holdfast. These results also indicate that GlcNAc polymers play an important role in the strength of the holdfast.

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