General approach to describing the properties of solid particles defined by the surface energy

Diffusion phenomena in solid particles were analyzed with the new material transport concept. It was assumed that total excess free energy in a system acted as a driving force for material transport so that the system changed to an equilibrium state. The new rate equation was adopted to analyze shape change, sintering and growth of grains. It was found that surface energy or ratio of grain boundary energy to surface energy was key factor for shape changes in these processes.

Download Full-text

Surface Energy of Filtration Media Influencing the Filtration Performance against Solid Particles, Oily Aerosol, and Bacterial Aerosol

Polymers ◽

10.3390/polym11060935 ◽

2019 ◽

Vol 11 (6) ◽

pp. 935 ◽

Cited By ~ 12

Author(s):

Seojin Jung ◽

Jaejin An ◽

Hyungjin Na ◽

Jooyoun Kim

Keyword(s):

Surface Energy ◽

Plasma Treatment ◽

Chemical Vapor ◽

Filtration Efficiency ◽

Dioctyl Phthalate ◽

Solid Particles ◽

Filtration Performance ◽

Bacterial Aerosol ◽

O2 Plasma Treatment ◽

O2 Plasma

Particulate airborne pollutants are a big concern to public health, and it brings growing attention about effective filtration devices. Especially, particulate matters smaller than 2.5 µm can reach the thoracic region and the blood stream, and the associated health risk can be exacerbated when pathogenic microbials are present in the air. This study aims at understanding the surface characteristics of nonwoven media that influence filtration performance against solid particles (sodium chloride, NaCl), oily aerosol (dioctyl phthalate, DOP), and Staphylococcus aureus (S. aureus) bacteria. Nonwoven media of polystyrene (PS) fibers were fabricated by electrospinning and its pristine surface energy (38.5 mN/m) was modified to decrease (12.3 mN/m) by the plasma enhanced chemical vapor deposition (PECVD) of octafluorocyclobutane (C4F8) or to increase (68.5 mN/m) by the oxygen (O2) plasma treatment. For NaCl particles and S. aureus aerosol, PS electrospun web showed higher quality factor than polypropylene (PP) meltblown electret that is readily available for commercial products. The O2 plasma treatment of PS media significantly deteriorated the filtration efficiency, presumably due to the quick dissipation of static charges by the O2 plasma treatment. The C4F8 treated, fluorinated PS media resisted quick wetting of DOP, and its filtration efficiency for DOP and S. aureus remained similar while its efficiency for NaCl decreased. The findings of this study will impact on determining relevant surface treatments for effective particulate filtration. As this study examined the instantaneous performance within 1–2 min of particulate exposure, and the further study with the extended exposure is suggested.

Download Full-text

The annealed (0001) α-alumina surface and its influence on thin-film growth

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100138051 ◽

1995 ◽

Vol 53 ◽

pp. 336-337

Author(s):

Michael W. Bench ◽

Paul G. Kotula ◽

C. Barry Carter

Keyword(s):

Electron Microscopy ◽

Surface Energy ◽

Film Growth ◽

Thin Film Growth ◽

Energy Calculations ◽

Transmission Electron ◽

Reflection Electron Microscopy ◽

Low Energy Electron ◽

Surface Nature

The growth of semiconductors, superconductors, metals, and other insulators has been investigated using alumina substrates in a variety of orientations. The surface state of the alumina (for example surface reconstruction and step nature) can be expected to affect the growth nature and quality of the epilayers. As such, the surface nature has been studied using a number of techniques including low energy electron diffraction (LEED), reflection electron microscopy (REM), transmission electron microscopy (TEM), molecular dynamics computer simulations, and also by theoretical surface energy calculations. In the (0001) orientation, the bulk alumina lattice can be thought of as a layered structure with A1-A1-O stacking. This gives three possible terminations of the bulk alumina lattice, with theoretical surface energy calculations suggesting that termination should occur between the Al layers. Thus, the lattice often has been described as being made up of layers of (Al-O-Al) unit stacking sequences. There is a 180° rotation in the surface symmetry of successive layers and a total of six layers are required to form the alumina unit cell.

Download Full-text

The nucleation of cavities at grain boundaries

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100126299 ◽

1987 ◽

Vol 45 ◽

pp. 288-291

Author(s):

P. J. Goodhew

Keyword(s):

Surface Tension ◽

Surface Energy ◽

Grain Boundaries ◽

Radiation Damage ◽

Impurity Concentration ◽

Driving Force ◽

Nucleation And Growth ◽

Phase Boundaries ◽

Cavity Nucleation ◽

Spherical Bubble

Cavity nucleation and growth at grain and phase boundaries is of concern because it can lead to failure during creep and can lead to embrittlement as a result of radiation damage. Two major types of cavity are usually distinguished: The term bubble is applied to a cavity which contains gas at a pressure which is at least sufficient to support the surface tension (2g/r for a spherical bubble of radius r and surface energy g). The term void is generally applied to any cavity which contains less gas than this, but is not necessarily empty of gas. A void would therefore tend to shrink in the absence of any imposed driving force for growth, whereas a bubble would be stable or would tend to grow. It is widely considered that cavity nucleation always requires the presence of one or more gas atoms. However since it is extremely difficult to prepare experimental materials with a gas impurity concentration lower than their eventual cavity concentration there is little to be gained by debating this point.

Download Full-text

Calculation of settling velocity of small solid particles in stratified suspension flows

International Journal of Multiphase Flow ◽

10.1016/s0301-9322(97)88556-4 ◽

1996 ◽

Vol 22 ◽

pp. 145

Author(s):

Y Pyrkin

Keyword(s):

Settling Velocity ◽

Solid Particles ◽

Suspension Flows

Download Full-text

Influence of Fiber Surface Energy on Mechanical Properties of Sisal Fiber - Bio Based Epoxy Composites

JOURNAL OF POLYMER MATERIALS ◽

10.32381/jpm.2018.35.04.7 ◽

2019 ◽

Vol 35 (4) ◽

pp. 485-496

Author(s):

S. RAJKUMAR ◽

◽

R. JOSEPH BENSINGH ◽

M. ABDUL KADER ◽

SANJAY K NAYAK ◽

...

Keyword(s):

Mechanical Properties ◽

Surface Energy ◽

Fiber Surface ◽

Epoxy Composites ◽

Sisal Fiber

Download Full-text

Surface energy of cellulosic materials: The effect of particle morphology, particle size, and hydroxyl number

TAPPI Journal ◽

10.32964/tj14.9.565 ◽

2015 ◽

Vol 14 (9) ◽

pp. 565-576 ◽

Cited By ~ 1

Author(s):

YUCHENG PENG ◽

DOUGLAS J. GARDNER

Keyword(s):

Particle Size ◽

Surface Energy ◽

Particle Morphology ◽

Nanofibrillated Cellulose ◽

Particle Sizes ◽

Hydroxyl Number ◽

Small Individual ◽

Dispersion Component ◽

Commercial Applications ◽

Lower Temperature

Understanding the surface properties of cellulose materials is important for proper commercial applications. The effect of particle size, particle morphology, and hydroxyl number on the surface energy of three microcrystalline cellulose (MCC) preparations and one nanofibrillated cellulose (NFC) preparation were investigated using inverse gas chromatography at column temperatures ranging from 30ºC to 60ºC. The mean particle sizes for the three MCC samples and the NFC sample were 120.1, 62.3, 13.9, and 9.3 μm. The corresponding dispersion components of surface energy at 30°C were 55.7 ± 0.1, 59.7 ± 1.3, 71.7 ± 1.0, and 57.4 ± 0.3 mJ/m2. MCC samples are agglomerates of small individual cellulose particles. The different particle sizes and morphologies of the three MCC samples resulted in various hydroxyl numbers, which in turn affected their dispersion component of surface energy. Cellulose samples exhibiting a higher hydroxyl number have a higher dispersion component of surface energy. The dispersion component of surface energy of all the cellulose samples decreased linearly with increasing temperature. MCC samples with larger agglomerates had a lower temperature coefficient of dispersion component of surface energy.

Download Full-text

A new method for quantifying the blocking of coated paperboard

TAPPI Journal ◽

10.32964/tj9.5.29 ◽

2010 ◽

Vol 9 (5) ◽

pp. 29-35 ◽

Cited By ~ 2

Author(s):

PAULINE SKILLINGTON ◽

YOLANDE R. SCHOEMAN ◽

VALESKA CLOETE ◽

PATRICE C. HARTMANN

Keyword(s):

Surface Roughness ◽

Fatty Acid ◽

Surface Energy ◽

Film Thickness ◽

External Factors ◽

Additive Concentration ◽

Pressure Surface ◽

Fatty Acid Amides ◽

Coated Surfaces ◽

Definite Period

Blocking is undesired adhesion between two surfaces when subjected to pressure and temperature constraints. Blocking between two coated paperboards in contact with each other may be caused by inter-diffusion, adsorption, or electrostatic forces occurring between the respective coating surfaces. These interactions are influenced by factors such as the temperature, pressure, surface roughness, and surface energy. Blocking potentially can be reduced by adjusting these factors, or by using antiblocking additives such as talc, amorphous silica, fatty acid amides, or polymeric waxes. We developed a method of quantifying blocking using a rheometer. Coated surfaces were put in contact with each other with controlled pressure and temperature for a definite period. We then measured the work necessary to pull the two surfaces apart. This was a reproducible way to accurately quantify blocking. The method was applied to determine the effect external factors have on the blocking tendency of coated paperboards, i.e., antiblocking additive concentration, film thickness, temperature, and humidity.

Download Full-text