scholarly journals Reclined trend of alkyl chain of sodium dodecylbenzenesulfonate molecules induced by friction

Friction ◽  
2022 ◽  
Author(s):  
Xianzhang Wang ◽  
Yuan Liu ◽  
Liran Ma ◽  
Xuefeng Xu ◽  
Yu Tian
Keyword(s):  
Alkyl Chain ◽  
Orientation Angle ◽  
Application Of Surfactants ◽  
Adsorption Model ◽  
Lateral Direction ◽  
Sodium Dodecylbenzenesulfonate ◽  
Sum Frequency ◽  
Molecular Monolayers ◽  
Molecular Arrangement ◽  
Solid Liquid Interface

AbstractSurfactants tend to adsorb on the surface/interface mostly in a directional manner. The alkyl chain orientation and conformation order for molecular monolayers of sodium dodecylbenzenesulfonate (SDBS) at low concentrations are studied by using the sum frequency generation vibrational spectroscopy (SFG-VS). The molecular arrangement of the surfactants adsorbed at the solid/liquid interface is further investigated. It is found that the arrangement of the SDBS at the interface becomes relatively ordered with increasing bulk concentration. Meanwhile, the orientation angle reduces gradually, and the molecules tend to be upright state. In addition, the effect of friction on the conformation order and orientation angle are also analyzed. The intensity of the SDBS vibrational contraction peak becomes lower after friction, which indicates that the anion has a reorientation process at the interface. The arrangement of molecules becomes more disordered due to friction. The orientation angle increases slightly, which indicates the monolayer has an inclined trend relative to the lateral direction on the interface. A modified adsorption model considering friction effect is proposed. This work may provide a reference for the further study of adsorption mechanism and application of surfactants.

scholarly journals Capillary force-induced superlattice variation atop a nanometer-wide graphene flake and its moiré origin studied by STM

2019 ◽  
Vol 10 ◽  
pp. 804-810
Author(s):  
Loji K Thomas ◽  
Michael Reichling
Keyword(s):  
Capillary Force ◽  
Orientation Angle ◽  
Scanning Tunneling ◽  
Total Expenditure ◽  
Liquid Interfaces ◽  
Tunneling Microscopy ◽  
Graphene Flake ◽  
Before And After ◽  
Solid Liquid Interface ◽  
Solid Liquid

We present strong experimental evidence for the moiré origin of superlattices on graphite by imaging a live transition from one superlattice to another with concurrent and direct measurement of the orientation angle before and after rotation using scanning tunneling microscopy (STM). This has been possible due to a fortuitous observation of a superlattice on a nanometer-sized graphene flake wherein we have induced a further rotation of the flake utilizing the capillary forces at play at a solid–liquid interface using STM tip motion. We propose a more “realistic” tip–surface meniscus relevant to STM at solid–liquid interfaces and show that the capillary force is sufficient to account for the total expenditure of energy involved in the process.

Real-Time Observation of High Temperature Interface between SiC Substrate and Solution during Dissolution of SiC

2013 ◽  
Vol 740-742 ◽  
pp. 35-38 ◽  
Author(s):  
Sakiko Kawanishi ◽  
Takeshi Yoshikawa ◽  
Kazuki Morita
Keyword(s):  
High Temperature ◽  
Real Time ◽  
Back Surface ◽  
Lateral Direction ◽  
Digital Microscope ◽  
Time Observation ◽  
A New Technique ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Real Time Observation

Precise morphological control of the interface between SiC and solution during the solution growth of SiC is crucial for obtaining high quality crystals with fewer defects and less step bunching. In this paper, a new technique for real-time observation of the high temperature interface between SiC and solution through the back surface of SiC was developed by focusing on the “wide” bandgap of SiC. Real-time observation of the interface during dissolution of SiC into an Fe-Si solvent alloy was carried out using a digital microscope, and the submicron-height structure of the solid-liquid interface was clearly observed at up to 1773 K. Interface morphologies, such as numerous hexagonal pits which were present at the initial stage of dissolution, followed by preferential dissolution in the lateral direction, were observed.

Contour tracking of an unknown planar object by regulating force for mobile robot navigation

Robotica ◽  
2006 ◽  
Vol 25 (3) ◽  
pp. 297-305 ◽  
Author(s):  
Seul Jung ◽  
Poongwoo Jeon ◽  
T. C. Hsia
Keyword(s):  
Mobile Robot ◽  
Contact Force ◽  
Control Method ◽  
Robot Navigation ◽  
Orientation Angle ◽  
Lateral Force ◽  
Wheeled Mobile Robot ◽  
Mobile Robot Navigation ◽  
Contour Tracking ◽  
Lateral Direction

SUMMARYIn this paper, a novel contour-tracking control method of an unknown planar object by lateral force regulation for wheeled mobile robot navigation is presented. The robot is required to follow the contour of an unknown object toward the goal position. Based on mobile robot dynamic equations, a force-control algorithm is proposed to maintain constant contact with a planar object. Measured contact force from an object is used not only to regulate a contact force in a lateral direction, but also to control the orientation angle of the robot to avoid collision with an object. Simulation and experiment of contour-tracking tasks of a wheeled mobile robot are conducted. Experimental results show that the contact force is well-regulated, and the robot arrives at the goal position successfully.

scholarly journals Water Structure at the Interface of Alcohol Monolayers as Predicted by Computational Vibrational Sum-Frequency Generation Spectroscopy

2018 ◽  
Author(s):  
Daniel R. Moberg ◽  
Qin Li ◽  
Sandeep K. Reddy ◽  
Francesco Paesani
Keyword(s):  
Alkyl Chain ◽  
Force Fields ◽  
Water Structure ◽  
Sum Frequency Generation ◽  
Interfacial Water ◽  
Sum Frequency ◽  
Frequency Generation ◽  
Computational Spectroscopy ◽  
Dynamics Simulations ◽  
Alcohol Monolayers

<div> <div> <div> <p>In this study, we investigate the structure of water at the interface of three long-chain alcohol monolayers differing in alkyl chain length through molecular dynamics simulations combined with modeling of vibrational sum-frequency generation (vSFG) spectra. The effects of alkyl chain parity on interfacial water is examined through extensive analysis of structural properties, hydrogen bonding motifs, and spectral features. Besides providing molecular-level insights into the structure of interfacial water, this study also demonstrates that, by enabling direct comparisons with experimental vSFG spectra, computational spectroscopy may be used to test and validate force fields commonly used in biomolecular simulations. The results presented here can thus serve as benchmarks for both further investigations to characterize ice nucleation induced by alcohol monolayers and refinement of popular biomolecular force fields. </p> </div> </div> </div>

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