Capillary Forces Described by Effective Contact Angle Distributions via Simulations of the Centrifuge Technique

MRS Advances ◽  
2016 ◽  
Vol 1 (31) ◽  
pp. 2237-2245
Author(s):  
Myles Thomas ◽  
Elizabeth Krenek ◽  
Stephen Beaudoin
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Smooth Surface ◽  
Adhesion Force ◽  
Capillary Forces ◽  
Angle Distribution ◽  
Particle Adhesion ◽  
Multiple Factors ◽  
Effective Contact ◽  
Condensed Moisture

ABSTRACTUnderstanding particle adhesion is vital to any industry where particulate systems are involved. There are multiple factors that affect the strength of the adhesion force, including the physical properties of the interacting materials and the system conditions. Surface roughness on the particles and the surfaces to which they adhere, including roughness at the nanoscale, is critically important to the adhesion force. The focus of this work is on the capillary force that dominates the adhesion whenever condensed moisture is present. Theoretical capillary forces were calculated for smooth particles adhered to smooth and rough surfaces. Simulations of the classical centrifuge technique used to describe particle adhesion to surfaces were performed based on these forces. A model was developed to describe the adhesion of the particles to the rough surface in terms of the adhesion to a smooth surface and an ‘effective’ contact angle distribution.

scholarly journals Prediction of Inter-particle Adhesion Force from Surface Energy and Surface Roughness

2011 ◽  
Vol 25 (4-5) ◽  
pp. 367-384 ◽  
Author(s):  
Laila J. Jallo ◽  
Yuhua Chen ◽  
James Bowen ◽  
Frank Etzler ◽  
Rajesh Dave
Keyword(s):  
Surface Roughness ◽  
Surface Energy ◽  
Adhesion Force ◽  
Particle Adhesion ◽  
Particle Adhesion Force

scholarly journals Assessing the Functional Properties of TiZr Nanotubular Structures for Biomedical Applications, through Nano-Scratch Tests and Adhesion Force Maps

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 900
Author(s):  
Maria Vardaki ◽  
Aida Pantazi ◽  
Ioana Demetrescu ◽  
Marius Enachescu
Keyword(s):  
Surface Roughness ◽  
Functional Properties ◽  
Bacterial Adhesion ◽  
Biomedical Applications ◽  
Adhesion Force ◽  
Roughness Parameters ◽  
Force Microscopy ◽  
Atomic Force ◽  
The Mean ◽  
Scratch Tests

In this work we present the results of a functional properties assessment via Atomic Force Microscopy (AFM)-based surface morphology, surface roughness, nano-scratch tests and adhesion force maps of TiZr-based nanotubular structures. The nanostructures have been electrochemically prepared in a glycerin + 15 vol.% H2O + 0.2 M NH4F electrolyte. The AFM topography images confirmed the successful preparation of the nanotubular coatings. The Root Mean Square (RMS) and average (Ra) roughness parameters increased after anodizing, while the mean adhesion force value decreased. The prepared nanocoatings exhibited a smaller mean scratch hardness value compared to the un-coated TiZr. However, the mean hardness (H) values of the coatings highlight their potential in having reliable mechanical resistances, which along with the significant increase of the surface roughness parameters, which could help in improving the osseointegration, and also with the important decrease of the mean adhesion force, which could lead to a reduction in bacterial adhesion, are providing the nanostructures with a great potential to be used as a better alternative for Ti implants in dentistry.

Effect of Water Temperature, pH Value, and Film Thickness on the Wettability Behaviour of Copper Surfaces Coated with Copper Using EB-PVD Technique

2019 ◽  
Vol 60 ◽  
pp. 124-141 ◽  
Author(s):  
Naser Ali ◽  
Joao Amaral Teixeira ◽  
Abdulmajid Addali
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Film Thickness ◽  
Water Temperature ◽  
Ph Value ◽  
Surface Wettability ◽  
Copper Surfaces ◽  
Force Microscopy ◽  
Atomic Force ◽  
Static Contact

This research investigates the effect of surface roughness, water temperature, and pH value on the wettability behaviour of copper surfaces. An electron beam physical vapour deposition technique was used to fabricate 25, 50, and 75 nm thin films of copper on the surface of copper substrates. Surface topographical analysis, of the uncoated and coated samples, was performed using an atomic force microscopy device to observe the changes in surface microstructure. A goniometer device was then employed to examine the surface wettability of the samples by obtaining the static contact angle between the liquid and the attached surface using the sessile drops technique. Waters of pH 4, 7, and 9 were employed as the contact angle testing fluids at a set of fixed temperatures that ranged from 20°C to 60°C. It was found that increasing the deposited film thickness reduces the surface roughness of the as-prepared copper surfaces and thus causing the surface wettability to diverge from its initial hydrophobic nature towards the hydrophilic behaviour region. A similar divergence behaviour was seen with the rise in temperature of water of pH 4, and 9. In contrast, the water of pH 7, when tested on the uncoated surface, ceased to reach a contact angle below 90o. It is believed that the observed changes in surface wettability behaviour is directly linked to the liquid temperature, pH value, surface roughness, along with the Hofmeister effect between the water and the surface in contact.

The Modification of Carbon Included Polyethylene Surface by Plasma Treatment for Metallizing Using a Low Pressure RF Discharge Plasma

2005 ◽  
Vol 8 (1) ◽  
Author(s):  
Jeou-Long Lee ◽  
Chung-Ming Liu ◽  
Kuen Ting ◽  
Wei-Kung Cheng ◽  
Takayoshi Tsuchida ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Surface Layer ◽  
Discharge Plasma ◽  
Treatment Time ◽  
Low Pressure ◽  
Rf Discharge ◽  
Nickel Layer ◽  
Good Adhesion ◽  
Polyethylene Surface

AbstractSurface modification of the carbon included polyethylene (semi-conductive PE) surface for metallizing using a low pressure RF discharge plasma has been carried out. The contact angle was used as a measure of the wettability of the PE surface. The roughness and the chemical bondings in PE surface layer were analized by DFM and XPS, respectively. Typical results show that the contact angle decreases from approximately 94° to below 10° after several minutes' treatment and recovers to a saturation value when it was put open to the air after treatment. The saturation value of the contact angle is smaller as the gas pressure for treatment is higher and the treatment time is longer but all are below approximately 60° which is still smaller than that of untreated. DFM and XPS results show that the surface roughness and the bondings C-O and C=O in the PE surface layer also increase with increasing the treatment time and seem to be responsible for improving the hydrophilic property of PE. After pretreatment process, nickel was coated on the PE sheet by electrodeposition method and a good adhesion between the nickel layer and the PE surface compared with that of untreated was obtained.

Enhancement of tribological properties and characteristic of polymer matrix composite (UHMWPE reinforced with short fibres of polyester) for Total Disc Replacement (TDR)

2020 ◽  
Vol 2 (102) ◽  
pp. 55-65
Author(s):  
M.N. Obaid ◽  
S.H. Radhi
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Wear Resistance ◽  
Composite Material ◽  
Thermal Properties ◽  
Coefficient Of Friction ◽  
Tribological Properties ◽  
Total Disc Replacement ◽  
Short Fibres ◽  
The Matrix

Purpose: The number of people suffering from Degenerative Disc Disease (DDD) is increasing. The disease causes heavy pain and restrict a number of day-to-day life activities. In extreme cases, the degraded disc is removed under total disc replacement which is usually made up of Ultra-High Molecular Weight Polyethylene (UHMWPE). The material has astounding biocompatible characteristics mechanical properties and wear resistance. However, these characteristics are insufficient in arthroplasty application. Therefore, research investigations are ongoing to improve tribological properties through reinforcement that may result in a composite material of UHMWPE. Thus the current study is aimed at reinforcing UHMWPE with short fibres of polyesters to enhance the tribological properties and surface characteristic so as to improve wear resistance and nourish the fibroblast cells on synthetic disc. Design/methodology/approach: The researcher prepared UHMWPE composite material, reinforced with different weight fractions of short polyester fibres (2, 4, 6, 8 and 10% following hot press method. Further pin-on-disc device was used to study the tribological properties (coefficient of friction and volume of wear). The study tested surface roughness and surface characteristics by atomic force microscopy (AFM) device, hardness by shore D device, contact angle to study the effect of polyester short fibres on wettability of UHMWPE surface and tested the thermal properties and crystalline degree using Differential Scanning Calorimetry measurement (DSC) device. Findings: The results infer that the wear resistance got improved when using 2% w.t polyester though it got decreased initially. However, the value was still more than neat UHMWPE. There was a decrease observed in coefficient of friction, but after 4 w.t% polyester, the coefficient of friction got increased due to increasing percentage of fibres which make it harder and stiff compared to UHMWPE. There was a decline observed in surface roughness due to alignment of the fibres with smooth surface. The contact angle got increased in a moderate range while the roughness enhanced the growth of fibroblast cell. The hardness of composite material got increased, because the fibres turned stiffer and harder than the matrix. DSC results infer the improvements in thermal stability due to high thermal properties of polyester fibres compared to UHMWPE. The degree of crystallinity got increased which in turn enhanced wear resistance, especially at 6 w.t % polyester fibres. There was a mild increase observed in density since the density of polyester is higher than polymer. Research limitations/implications: The major challenge was the dispersion of fibres. Uniform distribution of fibres within the matrix (UHMWPE) was achieved through two steps of mixing processes such as mechanical mixture and twin extruder. In future studies, fatigue tests must be conducted to study the behaviour of prepared composite materials under fatigue cycle. Practical implications: A significant objective is how to connect among different properties to obtain good improvement in tribological and surface properties so as to enhance wear resistance and growth of fibrolase cells. Originality/value: In this study, polymeric short fibres were used as reinforcement with polymeric matrix to enhance the wettability of fibres with matrix. In this way, the bonding among them got increased which supports the tribological, surface, and crystalline behaviour.

Modeling of Transport During Droplet Deposition and Spreading on Smooth and Microstructured Superhydrophilic Surfaces

2016 ◽  
Author(s):  
Jordan P. Mizerak ◽  
Van P. Carey
Keyword(s):  
Contact Angle ◽  
Contact Angles ◽  
Ansys Fluent ◽  
Effective Contact ◽  
Microstructured Surfaces ◽  
Static Contact ◽  
Droplet Behavior ◽  
Contact Line Pinning ◽  
The Impact ◽  
Superhydrophilic Surfaces

The dynamic behavior of impinging water droplets is studied in the context of varying surface morphologies on smooth and microstructured superhydrophilic surfaces. The goal of this study is to evaluate the capability of contact angle wall adhesion models to accurately produce spreading phenomena seen on a variety of surface types. We analyze macroscale droplet behavior, specifically spreading extent and impinging regime, in situations of varying microscale wetting character and surface morphology. Axisymmetric, volume of fluid (VOF) simulations with static contact angle wall adhesion are conducted in ANSYS Fluent. Simulations are performed on water for low Weber numbers (We<20) on surfaces with features of length scale 5–10μm. Advanced microstructured surfaces consisting of unique wetting characteristics and lengths on each face are also tested. Results show that while the contact angle wall adhesion model shows fair agreement for conventional surfaces, the model underestimates spreading by over 60% for surfaces exhibiting estimated contact angles below approximately 0.5°. Microstructured surfaces adapt the wetting behavior of smooth surfaces with higher effective contact angles based on contact line pinning on morphology features. The propensity of the model to produce Wenzel and Cassie-Baxter states is linked to the spreading radius, introducing an interdependency of microscale wetting and macroscale spreading behavior. Conclusions describing the impact of results on evaporative cooling are also discussed.

scholarly journals Deformation-Induced Roughening by Contact Compression in the Presence of Oils with Different Viscosity: Experiment and Numerical Simulation

2020 ◽  
Vol 68 (4) ◽  
Author(s):  
Grzegorz Starzynski ◽  
Ryszard Buczkowski ◽  
Bartlomiej Zylinski
Keyword(s):  
Numerical Simulation ◽  
Surface Roughness ◽  
Smooth Surface ◽  
Steel Sample ◽  
Normal Contact ◽  
Contact Loading ◽  
Uniaxial Stretching ◽  
Structure Interaction ◽  
Finite Element Calculations ◽  
Similarities And Differences

AbstractThe aim of the work is to show both the similarities and differences in the formation of deformation-induced roughness in contact compression in the presence of oil and the problem of free surface roughing during uniaxial stretching in a plastic area. The relationships between changes in the roughness are caused by the deformation of the sample and the viscosity of oil at the contact area. It has been shown that normal contact loading with the presence of oil initially leads to an increase in surface roughness, then to its smoothening. The results of the experimental research have been compared with numerical simulation made using FSI (Fluid Structure Interaction) and ABAQUS systems. Using finite element calculations, it was possible to explain the phenomenon of roughness formation on the surface of a smooth steel sample. The changes in the structure of the smooth surface resulting from compression in the presence of oil are caused by the rotation and deformation of surface grains. The roughness of this structure is dependent on the viscosity of oil: the more viscous the liquid is, the rougher texture is formed.

scholarly journals Surface Roughness of SiGe/Si(110) Formed by Stress-Induced Twins and the Solution to Produce Smooth Surface

2018 ◽  
Vol 06 (01) ◽  
pp. 25-31 ◽  
Author(s):  
Junji Yamanaka ◽  
Mai Shirakura ◽  
Chiaya Yamamoto ◽  
Naoto Utsuyama ◽  
Kei Sato ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Smooth Surface

Study on Permeability Coefficient of Different Bamboo/Fir Veneer Surface

2011 ◽  
Vol 311-313 ◽  
pp. 1634-1637 ◽  
Author(s):  
Li Hong Yao ◽  
Xi Ming Wang ◽  
Ben Hua Fei
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Permeability Coefficient ◽  
Phenolic Resin ◽  
Chinese Fir ◽  
Raw Material ◽  
Important Indicator ◽  
Veneer Surface ◽  
Surface Permeability ◽  
Analysis Models

Permeability coefficient is an important indicator of surface wettability and permeability, which influenced by the surface roughness. In this paper, bamboo and fir veneer as raw material, the contact angle of phenolic resin adhesives in different surface roughness of outer cuticle of bamboo, inner skin of bamboo, tight side of Chinese fir veneer and loose side of Chinese fir veneer were measured, and then use the software Spass non-linear fitting for permeability coefficient, and analysis of variance of the results by SAS software. The results show that permeability coefficient of four different kinds of surface variance analysis models are significantly, permeability coefficient of fir veneer is larger than bamboo surface; permeability coefficient of tight side of fir veneer is larger than loose side; permeability coefficient of inner skin of bamboo is larger than outer cuticle of bamboo. Permeability coefficients decrease first and then increased when mesh sandpaper increasing.

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