scholarly journals History-dependent Stress Relaxation of Liquids Under High-confinement: A Molecular Dynamics Study

2021 ◽  
Author(s):  
Hongyu Gao
Keyword(s):  
Molecular Structure ◽  
Stress Relaxation ◽  
Stress Tensor ◽  
Film Structure ◽  
Wave Number ◽  
Nanometer Scale ◽  
Predominant Role ◽  
Base Oil ◽  
Structural Relaxation Time ◽  
Molecule Dynamics

When liquids are confined into nanometer-scale slit, the induced layering-like film structure allows the liquid to sustain non-isotropic stresses and thus being load-bearing. Such anisotropic characteristics of liquid under confinement arise naturally from the liquids’ wave number dependent compressibility that does not need solidification to take place as a prerequisite. In other words, liquids under confinement can still remain fluidity with molecules being (sub-)diffusive. However, the extensively prolonged structural relaxation time can cause hysteresis of stress relaxation of confined molecules in response to the motions of confining walls and thereby yield the quasi-static stress tensor history-dependent. In this work, by means of molecule dynamics, the discrepancy of stress tensor of a highly confined key base-oil component, i.e. 1-decene trimer, is captured after its relaxation from being compressed and decompressed. The results indicate that among the effects (e.g. confinement, molecular structure, and film density) that can potentially affect confined stress tensor, the ordering status of the confined molecules plays a predominant role.

Co-curing of epoxy resins with aminated lignins: insights into the role of lignin homo crosslinking during lignin amination on the elastic properties

Holzforschung ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Marcus W. Ott ◽  
Christian Dietz ◽  
Simon Trosien ◽  
Sabrina Mehlhase ◽  
Martin J. Bitsch ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Elastic Properties ◽  
Nanometer Scale ◽  
Predominant Role ◽  
Force Microscopy ◽  
Atomic Force ◽  
Flexural Tests ◽  
The Relationship ◽  
Elastic Modules

AbstractTo improve the reactivity of lignin for incorporation into high value polymers, the introduction of amines via Mannich reaction is a commonly used strategy. During this functionalization reaction, intra- as well as intermolecular lignin–lignin crosslinking occurs, which can vastly change the elastic properties of the lignin, and therefore, the properties of the resulting polymer. Therefore, the molecular structure of the amine that is used for such a lignin functionalization may be of great importance. However, the relationship between the molecular structure of the amine and the elastic properties of the lignin-based polymer that is generated thereof, has not been fully understood. Herein, this relationship was investigated in detail and it was observed that the molecular flexibility of the amines plays a predominant role: The use of more flexible amines results in an increase in elasticity and the use of less flexible amines yields more rigid resin material. In addition to the macroscopic 3-point bending flexural tests, the elastic modules of the resins were determined on the nanometer scale by using atomic force microscopy (AFM) in the PeakForce tapping modus. Thus, it could be demonstrated that the intrinsic elasticities of the lignin domains are the main reason for the observed tendency.

Influence of nanometer scale film structure of ZDDP tribofilm on Its mechanical properties: A computational chemistry study

2009 ◽  
Vol 256 (4) ◽  
pp. 976-979 ◽  
Author(s):  
Tasuku Onodera ◽  
Takanori Kuriaki ◽  
Yusuke Morita ◽  
Ai Suzuki ◽  
Michihisa Koyama ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Computational Chemistry ◽  
Film Structure ◽  
Nanometer Scale

Effects of unsaturation on film structure and friction of fatty acids in a model base oil

2008 ◽  
Vol 326 (2) ◽  
pp. 530-536 ◽  
Author(s):  
S.M. Lundgren ◽  
M. Ruths ◽  
K. Danerlöv ◽  
K. Persson
Keyword(s):  
Fatty Acids ◽  
Film Structure ◽  
Base Oil ◽  
Model Base

Molecular Structure of Water at Interfaces:  Wetting at the Nanometer Scale

2006 ◽  
Vol 106 (4) ◽  
pp. 1478-1510 ◽  
Author(s):  
A. Verdaguer ◽  
G. M. Sacha ◽  
H. Bluhm ◽  
M. Salmeron
Keyword(s):  
Molecular Structure ◽  
Nanometer Scale ◽  
Structure Of Water

scholarly journals MOLECULAR STRUCTURE OF GELATIN EXTRACTED FROM PARROT (Scarus sp) FISH SCALES

2020 ◽  
Vol 8 (1) ◽  
pp. 15
Author(s):  
Jeszy Novianti Andakke ◽  
Inneke F M Rumengan ◽  
Hizkia H Y Nainggolan ◽  
Lasma R M E Parapat ◽  
Engel Pandey ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Fourier Transform ◽  
Moisture Content ◽  
Key Words ◽  
Triple Helix ◽  
Fourier Transform Infrared ◽  
Water Soluble ◽  
Wave Number ◽  
Fish Scales ◽  
Single Helix

One of the protein molecules of fish scales is water soluble gelatin. Gelatin of fish scales could be best substitute of commercial available gelatin which derived from porcine and bovine. The purpose of this study was to determine the molecular structure of gelatin extracted from marine fish scale using Fourier transform infrared (FTIR) analysis, and to obtain the moisture content, pH and yield of gelatin. Samples were prepared from the wet and dried scales. As for the standard gelatin, the gelatin of the two samples are characterized with several types of amide groups. The two gelatin samples were slight different in absorption of wave length for amide A, B, I, II and III groups indicating the instability of the functional groups which may influence viscosity and gel strength. For the wet scales derived gelatin, the wave number absorption was found to be 3412 cm-1 (amide A), 2421 cm-1 (amide B), 1653 cm-1 (amide I), 1400 cm-1 (amide II), and 1001 cm-1 (amide III), while for the dried scales derived gelatin was 3435 cm-1 (amide A), 2920 cm-1 (amide B), 1635 cm-1 (amide I), 1404 cm-1 (amide II), and 1036 cm-1 (amide III). The wave number absorption of amide III of gelatin is smaller than the one of collagen, because gelatin is in form of single helix, not triple helix. The wet scales derived and dried scales derived gelatin show the moisture content of 15.0% and 13.7%, and yield of 2.33% and 2.43%, .respectively. For both samples, the pH value was 7. Key words : gelatin, fish scales, molecule structure, moisture, yield, pH Abstrak Salah satu dari molekul protein sisik ikan adalah gelatin larut air. Gelatin sisik ikan dapat menjadi pengganti terbaik dari gelatin komersial yang tersedia yang berasal dari babi dan sapi. Tujuan dari penelitian ini adalah untuk menentukan struktur molekul gelatin yang diekstrak dari sisik ikan laut menggunakan Analisis FTIR (Fourier Transform Infrared), dan untuk mendapatkan kadar air, pH dan rendemen gelatin. Sampel disiapkan dari sisik basah dan sisik kering. Adapun standar gelatin, gelatin dari kedua sampel ditandai dengan beberapa jenis gugus amida. Kedua sampel gelatin sedikit berbeda dalam penyerapan panjang gelombang untuk amida A, B, I, II dan III yang menunjukkan ketidakstabilan kelompok fungsional yang dapat mempengaruhi viskositas dan kekuatan gel. Untuk gelatin sisik basah, panjang gelombang serapan ditemukan pada 3412 cm-1 (amida A), 2421 cm-1 (amida B), 1653 cm-1 (amida I), 1400 cm-1 (amida II), and 1001 cm-1 (amida III), sedangkan untuk gelatin sisik kering adalah 3435 cm-1 (amida A), 2920 cm-1 (amida B), 1635 cm-1 (amida I), 1404 cm-1 (amida II), and 1036 cm-1 (amida III). Panjang gelombang serapan amida III pada gelatin lebih kecil dibanding kolagen, sehingga gelatin berbentuk single helix, bukan triple helix. Gelatin sisik basah dan sisik kering mengadung kadar air 15,0% dan 13,7%, rendemen 2,33% and 2,43%, secara berturut-turut. Untuk kedua sampel memiliki nilai pH 7. Key words : gelatin, sisik ikan, struktur molekul, kadar air, rendemen, pH

scholarly journals Three-dimensional tracking of tethered particles for probing nanometer-scale single-molecule dynamics using plasmonic microscope

2021 ◽  
Author(s):  
Guangzhong Ma ◽  
Zijian Wan ◽  
Yunze Yang ◽  
Wenwen Jing ◽  
Shaopeng Wang
Keyword(s):  
Single Molecule ◽  
High Spatial Resolution ◽  
Imaging Technique ◽  
Three Dimensional ◽  
Axial Direction ◽  
Nanometer Scale ◽  
3D Tracking ◽  
Single Molecule Level ◽  
Plasmonic Imaging ◽  
Molecule Dynamics

Three-dimensional (3D) tracking of surface-tethered single-particle reveals the dynamics of the molecular tether. However, most 3D tracking techniques lack precision, especially in axial direction, for measuring the dynamics of biomolecules with spatial scale of several nanometers. Here we present a plasmonic imaging technique that can track the motion of ~100 tethered particles in 3D simultaneously with sub-nanometer axial precision at millisecond time resolution. By tracking the 3D coordinates of tethered particle with high spatial resolution, we are able to determine the dynamics of single short DNA and study its interaction with enzyme. We further show that the particle motion pattern can be used to identify specific and non-specific interactions in immunoassays. We anticipate that our 3D tracking technique can contribute to the understanding of molecular dynamics and interactions at the single-molecule level.

Influence of Hydrocarbon Base Oil Molecular Structure on Lubricating Properties in Nano-scale Thin Film

2019 ◽  
Vol 67 (4) ◽  
Author(s):  
Weiwei Wang ◽  
Peng Li ◽  
Shanzhi Sheng ◽  
Haitao Tian ◽  
Hongdun Zhang ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Thin Film ◽  
Base Oil ◽  
Nano Scale ◽  
Lubricating Properties

Stress Relaxation Study in 3C-SiC Microstructures by Micro-Raman Analysis and Finite Element Modeling

2013 ◽  
Vol 740-742 ◽  
pp. 673-676
Author(s):  
Nicolò Piluso ◽  
Ruggero Anzalone ◽  
Andrea Severino ◽  
Andrea Canino ◽  
Antonino La Magna ◽  
...  
Keyword(s):  
Finite Element ◽  
Stress Relaxation ◽  
Finite Element Modeling ◽  
Stress Tensor ◽  
Raman Mode ◽  
Mode Analysis ◽  
Free Standing ◽  
Element Modeling ◽  
Standing Structure ◽  
Si Films

In this paper, micro-Raman characterizations and Finite element modeling (FEM) of microstructures (cantilever, bridge, planar rotating probe) realized on single-crystal (100) 3C-SiC/Si films are performed. Transverse optical (TO) Raman mode analysis reveals the stress relaxation on the free standing structure (796.5 cm-1) respect to the stressed unreleased region (795.7 cm-1). The TO Raman mode exhibits an intense shift, up to 2 cm-1, located on the undercut region, where the Silicon substrate starts to be released. Such effect is ascribed to the modification of the Raman stress tensor that makes the generalized axial regime, described by diagonal components of the Raman stress tensor, unsuitable to describe the stress status on this region. Raman maps analysis and FEM simulations show the “activation” of the shear stress, i.e. non-diagonal components of the stress tensor. The aim of future works will be to minimize the stress field generation and the defects density within the epitaxial layer.

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