Measurement of the surface free energy of calcium-montmorillonite

Clay Minerals ◽  
1986 ◽  
Vol 21 (5) ◽  
pp. 899-907 ◽  
Author(s):  
P. Chassin ◽  
C. Jounay ◽  
H. Quiquampoix
Keyword(s):  
Contact Angle ◽  
Free Energy ◽  
Water Content ◽  
Surface Properties ◽  
Surface Free Energy ◽  
Surface Characteristics ◽  
Water Molecules ◽  
Solid Water

AbstractThe surface free energy of Ca-montmorillonite has been determined from measurement of the contact angle of water on an oriented deposit immersed in n-alkanes; the oriented deposits were equilibrated at different relative humidities. These experiments provided the polar, γSP, and dispersive, γSD, components of the surface free energy γs. The results indicate that: (1) γs is mainly due to dispersive forces (γSD ≃ 145 mJ.m−2) and, to a lesser degree, polar forces (γSP ≃ 35 mJ.m−2). (2) The value of the apparent surface free energy of the clay, γα, tends towards that measured for water when the solid water content exceeds 50 wt%. (3) The sorption of water molecules substantially modifies the surface free energy of the solid; γs decreases from 180 mJ.m−2 to 60 mJ.m−2 when the water content increases from 0 to 50%. These results agree with other observations made on solids whose surface characteristics are similar to montmorillonite, i.e. micas, silicates and glasses. In addition, variations of γs with water content can be related to the hydration processes of smectites. Finally, these results show that the silicate no longer influences the surface properties when the montmorillonite water content exceeds 60%.

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.

Molecular orientation of liquid aliphatic hydrocarbons on the surface and at the interface with water

1989 ◽  
Vol 54 (12) ◽  
pp. 3171-3186 ◽  
Author(s):  
Jan Kloubek
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Molecular Orientation ◽  
Phase Changes ◽  
Aliphatic Hydrocarbons ◽  
Water Molecules ◽  
Free Energies ◽  
Dispersion Component ◽  
System Water ◽  
Orientation Of Molecules

The validity of the Fowkes theory for the interaction of dispersion forces at interfaces was inspected for the system water-aliphatic hydrocarbons with 5 to 16 C atoms. The obtained results lead to the conclusion that the hydrocarbon molecules cannot lie in a parallel position or be randomly arranged on the surface but that orientation of molecules increases there the ration of CH3 to CH2 groups with respect to that in the bulk. This ratio is changed at the interface with water so that the surface free energy of the hydrocarbon, γH, rises to a higher value, γ’H, which is effective in the interaction with water molecules. Not only the orientation of molecules depends on the adjoining phase and on the temperature but also the density of hydrocarbons on the surface of the liquid phase changes. It is lower than in the bulk and at the interface with water. Moreover, the volume occupied by the CH3 group increases on the surface more than that of the CH2 group. The dispersion component of the surface free energy of water, γdW = 19.09 mJ/m2, the non-dispersion component, γnW = 53.66 mJ/m2, and the surface free energies of the CH2 and CH3 groups, γ(CH2) = 32.94 mJ/m2 and γ(CH3) = 15.87 mJ/m2, were determined at 20 °C. The dependence of these values on the temperature in the range 15-40 °C was also evaluated.

Within-tree variations in the surface free energy of wood assessed by contact angle analysis

2011 ◽  
Vol 46 (1-3) ◽  
pp. 287-298 ◽  
Author(s):  
Davide Rossi ◽  
Sergio Rossi ◽  
Hubert Morin ◽  
Antonio Bettero
Keyword(s):  
Contact Angle ◽  
Free Energy ◽  
Surface Free Energy ◽  
Contact Angle Analysis

Hydrophobic and Oleophilic Filter Paper for Oil/Water Separation

2019 ◽  
Vol 798 ◽  
pp. 385-390
Author(s):  
Sunisa Jindasuwan ◽  
Sitthisuntorn Supothina
Keyword(s):  
Contact Angle ◽  
Free Energy ◽  
Surface Free Energy ◽  
Water Contact Angle ◽  
Filter Paper ◽  
Diesel Oil ◽  
Selective Removal ◽  
Water Contact ◽  
Water Separation ◽  
Filter Papers

The separation of oil from water is significance for environmental de-pollution application. To obtain selectivity of liquid, filter papers were coated to bear highly hydrophobic and oleophilic functionality that can allow only oils to pass through them. The coating solutions were prepared by mixing poly(methylhydro siloxane, PMHS) and fumed silica at various proportions. To determine an optimum coating condition, properties of the treated filter papers were investigated by measuring water contact angle and surface free energy, examining surface morphology and testing for selective removal of diesel oil from water. The optimum coating solution was at the PMHS:fumed silica weight ratio of 1.25:1.00. The treated filter paper exhibited high hydrophobicity with water contact angle of 142.80 ± 0.36 degrees and surface free energy of 0.78 mJ/m2. In addition, it exhibited high selective removal of diesel oil from water with oil absorption capacity of 2.3 g/g.

Measurement of specific surface free energy of ruby and quartz single crystals using contact angle of liquids

2007 ◽  
Vol 42 (12) ◽  
pp. 1217-1221 ◽  
Author(s):  
Takaomi Suzuki ◽  
Naoki Sugihara ◽  
Eiichi Iguchi ◽  
Katsuya Teshima ◽  
Shuji Oishi ◽  
...  
Keyword(s):  
Contact Angle ◽  
Free Energy ◽  
Specific Surface ◽  
Single Crystals ◽  
Surface Free Energy
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