Surface roughness dominated wettability of carbon fiber in gas diffusion layer materials revealed by molecular dynamics simulations

Author(s):  
X.L. Wang ◽  
W.K. Wang ◽  
Z.G. Qu ◽  
G.F. Ren ◽  
H.C. Wang
Soft Matter ◽  
2019 ◽  
Vol 15 (3) ◽  
pp. 424-432 ◽  
Author(s):  
J. Wesley Barnett ◽  
Sanat K. Kumar

We show that coarse-grained molecular dynamics simulations do not capture experimental trends for the gas diffusion in matrix-free polymer-grafted nanoparticle-based membranes.


Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7327
Author(s):  
Robin Vacher ◽  
Astrid S. de Wijn

Roughness of surfaces is both surprisingly ubiquitous on all length scales and extremely relevant practically. The appearance of multi-scale roughness has been linked to avalanches and plastic deformation in metals. However, other, more-complex materials have mechanisms of plasticity that are significantly different from those of metals. We investigated the emergence of roughness in a polymer under compression. We performed molecular-dynamics simulations of a slab of solid polyvinyl alcohol that was compressed bi-axially, and we characterised the evolution of the surface roughness. We found significantly different behaviour than what was previously observed in similar simulations of metals. We investigated the differences and argue that the visco-elasticity of the material plays a crucial role.


2011 ◽  
Vol 194-196 ◽  
pp. 1620-1623 ◽  
Author(s):  
Xue Jun Zhang ◽  
Hao Pei ◽  
Zeng Min Shen

Gas diffusion layer is a very important component in fuel cell, and carbon fiber paper is widely used as substrate of gas diffusion layer. This paper has developed one way to produce carbon fiber paper from carbon fiber felt with or without pretreatment. The properties and microstructure of carbon fiber paper were also stdied. The results show that the pretreatment of carbon fiber felt is helpful to prepare carbon fiber paper with good properties. The content of carbon derived from resin during pretreatment has effects on density, thickness, porosity, gas permeability, porosity and tensile streagth of carbon fiber paper. Carbon fiber paper made from carbon fiber felt with pretreatment has better interface adhension than that of carbon fiber paper made from carbon fiber felt without pretreatment. Carbon fiber paper was produced with thickness of 0.28mm, density of 0.43g/cm3, porosity of 77%, gas permeability of 2500 mL•mm/(cm2•hr•mmAq), specific resistance of 0.017Ω•cm and tensile strength of 18MPa, which is a promising materials for fuel cell electrode.


2014 ◽  
Vol 118 (24) ◽  
pp. 12734-12743 ◽  
Author(s):  
Daniel Holden ◽  
Kim E. Jelfs ◽  
Abbie Trewin ◽  
David J. Willock ◽  
Maciej Haranczyk ◽  
...  

2011 ◽  
Vol 462-463 ◽  
pp. 937-942 ◽  
Author(s):  
Nanik Indayaningsih ◽  
Dedi Priadi ◽  
Anne Zulfia ◽  
Suprapedi

The main compound of natural fibers is a hydrocarbon. The heating of hydrocarbon in inert gas produces charcoal or carbon. Carbon materials are widely used for several purposes depending on the physical and electric properties, for example for hydrogen storage, conductive or reinforced plastics, catalyst supports, batteries and fuel cells. The main raw material of Gas diffusion Layer (GDL) of the Proton Exchange Membrane Fuel Cell (PEMFC) is a carbon. The properties of GDL are porous and electron-conductive material, because of the function of GDL is to distribute the gas as fuel and electricity conductors. This study aims to analyze the carbon fibers made from coconut fibers for the application of GDL materials. The carbon fiber was made using pyrolysis process in the inert gas (nitrogen) at a certain temperature according to the analysis of Differential Thermal Analysis (DTA) 3000C, 4000C, 5000C, 6000C, and 9000C. The crystalstructure, carbon content, powder density and morphology of carbon fibers were observed using X-Ray Diffraction (XRD), fixed carbon according to ASTM D 1762-64, Archimedes method (BS 19202 Part 1A), and Scanning Electron Microscope (SEM), respectively. The results showed that the structure of carbon was amorphous, and content of 51% ̶ 71%, powder density of 0.42g/cm3 ̶ 0.71g/cm3. The morphology having many parallel hollows like a tube that are close to each other with diameters of 2m ̶ 10m, and in the wall of tube there are some porous with sizes around 1m. According to this analysis, the coconut carbon fiber enables to be applied as candidate for a basic material of GDL.


Soft Matter ◽  
2018 ◽  
Vol 14 (18) ◽  
pp. 3550-3556 ◽  
Author(s):  
Jiaxiang Li ◽  
Mingming Ding ◽  
Ran Zhang ◽  
Tongfei Shi

We employ molecular dynamics simulations to simulate the diffusion dynamics of a single polymer adsorbed on surfaces with different roughnesses, which are characterized by the separation distance between obstacles and the height of obstacles.


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