Methods Used to Measure Contact Forces

Fused glass or quartz with a hydrophilic surface, contact angle 0, does not exceed a few 

Methylated fused glass in which the surface is covered with a dense layer of chemisorbed CH3 groups. Such glass has a hydrophobic surface producing contact angles on the order of 100°-105°. 

Fluorinated fused glass that has a surface even more hydrophobic than the methylated one. 

Physical-Chemical Mechanics of Disperse Systems and Materials 

FIGURE 1.28 A diagram illustrating the method for measuring the contact forces in a liquid medium between solid particles (a) and a schematic illustration of the corresponding instrument (b) 1, magnetoelectric galvanometer 2, holder (L-shaped tube, 1 mm in diameter) 3, holder connected to a manipulator 4-manipulator 5, immersed in cuvette. (From Shchukin, E.D. et al., Colloid and Surface Chemistry, Elsevier, Amsterdam, the Netherlands, 2001.) 

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