Standard contact angle measurement methods

Table 2.4 Standard Contact Angle Measurement Methods for Various Materials...

ASTM C813-90 (1994)e1 Standard Test Method for Hydrophobic Contamination on Glass by Contact Angle Measurement. Method covers the detection of hydrophobic contamination on glass surfaces by means of contact angle measurement. 

ASTM D5946-96 Standard Test Method for Corona-treated Polymer Films using Water Contact Angle Measurement. Method covers the measurement of contact angle of water droplets on corona-treated polymer film surfaces the results are used to estimate the film s wetting tension. 

Standard test method for corona-treated polymer films using water contact angle measurements, ASTM D5946-96. 

Surfactant testing and reagent screening can be performed in a variety of ways. The simplest and most common technique used in the petroleum industry is the standard blender test [7]. Other test methods [4] include Ross-Miles foam height test, flow loop testing, capillary foam testers, contact angle measurements, tensiometers and actual field evaluations. Due to its low cost, easy duplication and ability to be used in the field, blender testing has become the norm in the industry for foam based fluids. 

Schultz et al. [175] used fl(yP) " as a comparison scale. The parameter a is the area of the adsorbed probe molecule [176]. It is obtained from IGC measurements on neutral reference solids such as polyethylene or PTFE. Some examples are n-hexane, 51.5A ether, 47A chloroform, 44A and acetone, 42.5A. In standard fashion, yP is determined from contact angle measurements on reference solids [176]. Once again, some probes fall under the reference line of the n-alkanes, and the data are difficult to interpret. This constitutes a limiting factor of this method. 

ASTM D5725-99 Standard Test Method for Surface Wettability and Absorbency of Sheeted Materials using an Automated Contact Angle Tester. Method measures the contact angle of a test liquid on a flat sample of a film or a paper substrate under specified conditions. 

Such a development would be impossible without the generation of new experimental techniques extending the possibilities of studies of supramolecular systems. One such new technique is the vibrational (or infrared-visible) spectroscopy sum frequency generation [8] enabling one to lookatjustthe outer monolayer, thus providing more information than more standard methods like contact angle and surface tension measurements [9]. 

Several standards have been written to define methods for measuring the contact angle for different applications (Table 2.4). The objective of these methods is to mainly provide procedures for the comparison of the surface energy of industrial materials. 

Finally, apart from the standardized test methods that should be used, it is of extreme importance for reasons of consistency that researchers measure both static and dynamic contact angles in their experiments, otherwise it is impossible to compare the performance of a surface to studies published by other researchers. Selecting also standardized physical quantities and materials in the tests would also be beneficial (e.g. applied pressure and abradant materials). 

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