Interaction force between an air bubble and a hydrophilic spherical particle in water, measured by the colloid probe technique

Contribution of different physical forces to the disjoining pressure of a thin water film being pressed by an oil droplet

“…The water forms a thin layer on the solid substrate which acts as a barrier to the lubricating oil droplets to reach the metal surface. The focus of the present work is to investigate conditions which permit the disjoining of the water film [1][2][3][4][5][6][7][8] to allow the oil to lubricate the metal substrate. We explore here the forces which act on the oil droplet approaching the solid substrate in the water medium.…”

“…We explore here the forces which act on the oil droplet approaching the solid substrate in the water medium. An electric double layer forms in the electrolyte [4][5][6][7][8][9][10][11] confined between the oil and the solid substrate. The dynamic nature of the process generates entropic/electrostatic forces [2][3][4][5][6][7][8][9][10][11].…”

“…Depending on the chemical/electrical nature of the substrate and the oil-water interface the surface charge may also change during approach by ion exchange [2][3][4][5][6][7] as the counterions are driven towards and adsorbed by the negatively charged droplet and/or the substrate [2][3][4][5][6][7][8][9][10][11]. A summation of the entropic and the short ranged van der Waal force is designated the DLVO interaction [1][2][3][4][5][6][7][8][9][10][11]. Other possible forces of interaction are capillary forces [11], hydration forces [10,11,13,14] and hydrophobic attraction which may be short ranged (0-10 nm) or long ranged ($30 nm) [5,11,12].…”

“…For the oil/water interface we measure the potential using a dynamic light scattering experiment. For the substrates; mica, PTFE and steel, we assume the values of surface potential W as reported by others [4,[15][16][17][18][19][20][21][22][23] 'as a first iteration' estimate.…”

Influência da dissipação de energia na cinética da flotação aniônica direta de apatita em meio básico.

“…Diversos estudos têm sido desenvolvidos utilizando essa técnica (Englert, 2008;Englert et al, 2009, Nguyen et al, 2003, esses estudos avaliam o efeito da aproximação da partícula até uma bolha sem a influência das forças hidrodinâmicas existentes nas células de flotação.…”