scholarly journals Surface Testing of Dental Biomaterials—Determination of Contact Angle and Surface Free Energy

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2716
Author(s):  
Aneta Liber-Kneć ◽  
Sylwia Łagan
Keyword(s):  
Contact Angle ◽  
Free Energy ◽  
Surface Energy ◽  
Surface Free Energy ◽  
Sessile Drop ◽  
Dental Materials ◽  
Free Energy Calculations ◽  
Critical Surface ◽  
Free Energies ◽  
Acrylic Resins

The key goal of this study was to characterize surface properties of chosen dental materials on the base on the contact angle measurements and surface free energy calculations. Tested materials were incubated in the simulated oral environment and drinks to estimate an influence of conditions similar to those in the oral cavity on wetting and energetic state of the surface. Types of materials were as follows: denture acrylic resins, composite and PET-G dental retainer to compare basic materials used in a prosthetics, restorative dentistry and orthodontics. The sessile drop method was used to measure the contact angle with the use of several liquids. Values of the surface free energies were estimated based on the Owens–Wendt, van Oss–Chaudhury–Good and Zisman’s methods. The research showed that surface wetting depends on the material composition and storage conditions. The most significance changes of CA were observed for acrylic resins (84.7° ± 3.8° to 65.5° ± 3.5°) and composites (58.8° ± 4.1° to 49.1° ± 5.7°) stored in orange juice, and for retainers (81.9° ± 1.8° to 99.6° ± 4.5°) incubated in the saline solution. An analysis of the critical surface energy showed that acrylic materials are in the zone of good adhesion (values above 40 mJ/m2), while BIS-GMA composites are in the zone of poor adhesion (values below 30 mJ/m2). Study of the surface energy of different dental materials may contribute to the development of the thermodynamic model of bacterial adhesion, based on the surface free energies, and accelerate the investigation of biomaterial interaction in the biological environment.

Determination of Surface Free Energy and Contact Angle for Hydrolyzed Shellac

2012 ◽  
Vol 506 ◽  
pp. 270-273 ◽  
Author(s):  
P. Kraisit ◽  
S. Limmatvapirat ◽  
J. Nunthanid ◽  
Manee Luangtana-Anan ◽  
K. Terada ◽  
...  
Keyword(s):  
Contact Angle ◽  
Free Energy ◽  
Surface Free Energy ◽  
Sessile Drop ◽  
Polar Group ◽  
Sessile Drop Technique ◽  
Hydrolysis Process ◽  
Polar Force ◽  
Drop Technique

The purpose of this research was to determine surface free energy and contact angle of hydrolyzed shellac by using sessile drop technique. It is a method for determination of contact angle by placing a drop of liquid on a substrate and the surface free energy is then calculated by using the Wus equation. The substrate in this study was the hydrolyzed shellac prepared by hydrolysis of the native shellac at various times; 0, 15, 30 and 45 min using 2.0 %w/w sodium hydroxide. Water, formamide and ethylene glycol were liquids used for the investigation of the contact angle and surface free energy. The effect of hydrolysis time tended to reduce the contact angle and increase in the total surface free energy and polar force of hydrolyzed shellac. The result could be due to the breaking of the ester bonds of shellac during the hydrolysis process causing the higher free carboxyl group giving the higher polar group indicating by higher polar force and surface free energy. Therefore, the contact angle and surface free energy detected by sessile drop technique could be of benefit for the determination of hydrolysis process.

Surface Free Energy of Boron-Compounds Modified Poplar Veneer

2013 ◽  
Vol 753-755 ◽  
pp. 843-847 ◽  
Author(s):  
Chen Chen Li ◽  
Zhi Yong Qin ◽  
Qian Zhang ◽  
Jiang Zhang Li
Keyword(s):  
Contact Angle ◽  
Free Energy ◽  
Surface Free Energy ◽  
Sessile Drop ◽  
Untreated Wood ◽  
Initial Contact ◽  
Boron Compounds ◽  
Acid Base ◽  
The Difference ◽  
Better Than

The contact angle of three different reference liquids (i.e. distilled water, diiodomethane, and formamide) was measured by the sessile drop method by gently placing droplet onto the surface of the boron-compounds treated poplar veneer in this study. The permeability of the modified poplar veneer was evaluated. The surface free energy, as well as two components, namely, Lifshizvander Waals(LW) and Acid-base(AB), were calculated by the Acid-base theory, whereas the polar and nonpolar components were calculated according to the OWRK theory. The result shows that the initial contact angle of boron-compounds modified poplar veneer are significantly less than the untreated wood, which indicates that the wettability of boron-compounds polar veneer is better than the untreated wood. The same situation applies to the permeability. In addition, the surface free energy of boron-compounds modified poplar veneer is reduced, but the difference is very small.

Surface free energy of a soil clay fraction in relation to aggregate stability

Clay Minerals ◽  
1993 ◽  
Vol 28 (1) ◽  
pp. 145-148
Author(s):  
B. Jańczuk ◽  
G. Józefaciuk ◽  
M. Hajnos ◽  
T. Bialopiotrowicz ◽  
A. Kliszcz
Keyword(s):  
Contact Angle ◽  
Free Energy ◽  
Surface Free Energy ◽  
Clay Fraction ◽  
Aggregate Stability ◽  
Soil Aggregate ◽  
Free Energies ◽  
Soil Aggregate Stability ◽  
Soil Clay ◽  
Energy Components

When studying surface free energies of clays in relation to clay composition, we calculated that in some instances the aggregate stability should be higher for Na- then for Ca-forms. This raised the question as to whether the results obtained with the surface free energy approach are reliable for estimation of soil aggregate stability. The aim of the present work was to measure the surface free energy components and attractive forces for a clay calculated from measurements of the contact angle of glycerol, diiodomethane and cis-decalin and to compare them with results of penetrometrical measurements.

scholarly journals Influence of Conditions for Production and Thermo-Chemical Treatment of Al2O3 Coatings on Wettability and Energy State of Their Surface

Coatings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 681 ◽  
Author(s):  
Mateusz Niedźwiedź ◽  
Władysław Skoneczny ◽  
Marek Bara
Keyword(s):  
Contact Angle ◽  
Free Energy ◽  
Surface Free Energy ◽  
Chemical Treatment ◽  
Sessile Drop ◽  
Energy State ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Sodium Sulphate ◽  
Oxide Coatings

This article presents the influence of the anodizing parameters and thermo-chemical treatment of Al2O3 coatings made on aluminum alloy EN AW-5251 on the surface free energy. The oxide coating was produced by DC (Direct Current) anodizing in a ternary electrolyte. The thermo-chemical treatment of the oxide coatings was carried out using distilled water, sodium dichromate and sodium sulphate. Micrographs of the surface of the Al2O3 coatings were characterized using a scanning microscope (SEM). The chemical composition of the oxide coatings was identified using EDS (Energy Dispersive X-ray Spectroscopy) microanalysis. Surface free energy (SFE) calculations were performed by the Owens–Wendt method, based on wetting angle measurements made using the sessile drop technique. The highest value of surface free energy for the only anodized coatings was 46.57 mJ/m2, and the lowest was 37.66 mJ/m2. The contact angle measurement with glycerine was 98.06° ± 2.62°, suggesting a hydrophobic surface. The thermo-chemical treatment of the oxide coatings for most samples contributed to a significant increase in SFE, while reducing the contact angle with water. The highest value of surface free energy for the coatings after thermo-chemical treatment was 77.94 mJ/m2, while the lowest was 34.98 mJ/m2. Taking into account the contact angle measurement with glycerine, it was possible to obtain hydrophobic layers with the highest angle of 109.82° ± 4.79° for the sample after thermal treatment in sodium sulphate.

scholarly journals Potentials of lignocellulosic agricultural residues in paper production

2021 ◽  
Vol 11 (3) ◽  
pp. 72-77
Author(s):  
Ivana Plazonić ◽  
Maja Rudolf ◽  
Valentina Radić Seleš ◽  
Irena Bates ◽  
Katja Petric Maretić
Keyword(s):  
Contact Angle ◽  
Free Energy ◽  
Surface Free Energy ◽  
Sessile Drop ◽  
Surface Characteristics ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Hydrophilic Material ◽  
Printing Processes ◽  
High Absorption

Surface characteristics of printing substrates are of the utmost importance to all types of paper that interact with ink. During all types of printing processes, the behaviour of the liquid phase (ink or dye) on the paper is directly defined by the paper cellulose-based surface. The printed ink spreads and penetrates more into paper fibres when the paper surface is rougher and more permeable. Contact angle measurements by sessile drop method are considered the most appropriate for determining the paper sheet surface energy. Paper as hydrophilic material has a high absorption rate resulting in a low contact angle. The objective of this study was to evaluate the surface free energy of laboratory-made papers containing straw pulp obtained from residues after the harvest of the most cultivated cereals in Croatia (wheat, barley and triticale). The obtained surface free energy results are promising for straw pulp usage in the manufacture of printing paper.

Effect of Various Types of Hydroxypropyl Methylcellulose (HPMC) Films on Surface Free Energy and Contact Angle

2014 ◽  
Vol 1060 ◽  
pp. 107-110 ◽  
Author(s):  
Pakorn Kraisit ◽  
Manee Luangtana-Anan ◽  
Narong Sarisuta
Keyword(s):  
Contact Angle ◽  
Free Energy ◽  
Surface Free Energy ◽  
Sessile Drop ◽  
Hydroxypropyl Methylcellulose ◽  
Physicochemical Characteristics ◽  
Basic Knowledge ◽  
Sessile Drop Technique ◽  
Buccal Films ◽  
Drop Technique

The aim of this study was to investigate the physicochemical characteristics of various viscosity grades of hydroxypropyl methylcellulose (HPMC) for mucoadhesive buccal films. The HPMC used in this study was K4M, K15M and K100M which their viscosity were 4000, 15000 and 100000 mPas respectively. Using HPMC as film forming base matrix, all intrinsic characteristics of each HPMC grade is required as basic knowledge for the development of mucoadhesive buccal films. To understand the primary essential parameters, surface free energy and contact angle of various HPMC grades were determined. Sessile drop technique was used in this study to determine contact angle of HPMC and surface free energy was then evaluated by using the Wu’s equation. The results showed that the increase in viscosity of HPMC film tended to decrease the polar force and total surface free energy but increased the contact angle. These parameters indicated that the hydrophilic character of HPMC was influenced by its viscosity. Our study suggested that the polar and dispersive force detected by sessile drop technique could be beneficial for the further design and development of mucoadhesive buccal films.

Simulations of the Structure and Properties of the Polyethylene Crystal Surface

1995 ◽  
Vol 408 ◽  
Author(s):  
J. L. Wilhelmi ◽  
G. C. Rutledge
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Crystal Surface ◽  
Excess Entropy ◽  
Free Energy Calculations ◽  
Intermolecular Potential ◽  
Free Energies ◽  
Free Energy Surface ◽  
Lattice Mode ◽  
Molecular Layers

AbstractThe structures and thermodynamic properties of the (100), (010), and (110) lateral surfaces of extended-chain polyethylene crystals between 0 K and 300 K were determined by free energy minimization using consistent quasi-harmonic lattice dynamics. Slight rotations of the outermost chains from their corresponding orientations in the bulk were observed. These deviations from bulk structure were confined to the first three molecular layers (approximately 10 Å) at the surface. Surface free energy calculations found the (110) surface to be the most stable over the entire temperature range modeled, with free energies ranging from 95.4 erg/cm2 to 103.5 erg/cm2, at temperatures of 0 K and 300 K, respectively. Surface free energies of the (100) and (010) surfaces were found to be at least 15% higher than the (110) surface, with the (100) surface slightly more stable than the (010) surface, over all temperatures considered. Surface free energy increases as the density of chains at the surface decreases. The surface free energy at low temperatures was determined predominantly by intermolecular potential energy; at higher temperatures, excess entropy accounted for nearly half the surface free energy. Surface entropy was almost entirely due to lattice mode motions.

Examination of the lubricant storing and releasing ability of thermally sprayed surfaces

2011 ◽  
Vol 2 (2) ◽  
pp. 101-105
Author(s):  
L. Fazekas ◽  
Z. S. Tiba ◽  
G. Kalácska
Keyword(s):  
Free Energy ◽  
Surface Energy ◽  
Surface Free Energy ◽  
Essential Role ◽  
Index Number ◽  
Adhesion Ability ◽  
Thermally Sprayed ◽  
Proper Operation

Abstract The lubricant storing and releasing ability of the thermally sprayed surfaces plays an essential role in the proper operation of the components. In the case of porous sprayed surfaces the lubricant storing and releasing ability depends mainly on porosity and the surface energy (adhesion susceptibility). The adhesion ability can also be expressed indirectly with an index number that is by determining the surface free energy.

SAMPL6 Octanol-Water Partition Coefficients from Alchemical Free Energy Calculations with MBIS Atomic Charges

2019 ◽  
Author(s):  
Maximiliano Riquelme ◽  
Esteban Vöhringer-Martinez
Keyword(s):  
Free Energy ◽  
Electron Density ◽  
Free Energy Calculations ◽  
Basis Set ◽  
Energetic Cost ◽  
Atomic Charges ◽  
Free Energies ◽  
Energy Calculations ◽  
Alchemical Free Energy ◽  
Alchemical Free Energy Calculations

In molecular modeling the description of the interactions between molecules forms the basis for a correct prediction of macroscopic observables. Here, we derive atomic charges from the implicitly polarized electron density of eleven molecules in the SAMPL6 challenge using the Hirshfeld-I and Minimal Basis Set Iterative Stockholder(MBIS) partitioning method. These atomic charges combined with other parameters in the GAFF force field and different water/octanol models were then used in alchemical free energy calculations to obtain hydration and solvation free energies, which after correction for the polarization cost, result in the blind prediction of the partition coefficient. From the tested partitioning methods and water models the S-MBIS atomic charges with the TIP3P water model presented the smallest deviation from the experiment. Conformational dependence of the free energies and the energetic cost associated with the polarization of the electron density are discussed.

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