Plasma-treated polymer surfaces contact angle measurements

The sessile droplet contact angle measurement is a simple and accurate method to obtain information pertinent to the surface energy of a sample. The Wilhelmy balance method, on the other hand, is a very useful method to investigate the surface dynamic aspect of a sample, which will be described in the following sections. The instability of some of plasma-treated polymer surface observed by the Wilhelmy balance method is also described in Chapter 30. 

Rearrangement of Functional Groups of Plasma-Treated Polymer Surfaces by Contact Angle Measurements... 

The decay of hydrophobicity manifested by the sessile droplet contact angles of water as well as of XPS FIs peak intensity is observed in nylon 6 and PET films treated similarly. There is a direct linear correlation between the contact angles of water and the intensity of XPS F Is peaks for each substrate polymer as shown in Figure 25.4. This correlation confirms that the increase and the decrease of the contact angle of water on the surface of plasma-treated films are due mainly to the change in the surface concentration of fluorine-containing moieties, which enable us to deal with the decay and the recovery phenomena by either measurement. 

Another noteworthy factor which influences the aging characteristics of an atmospheric plasma treated roll polymer surface is temperature. Practical industrial experience has indicated that lower in-plant or in-warehouse storage temperature will reduce the decay rate of surface tension. This has been measured by contact angle for nonporous roll polymers whereby a change in the advancing contact... 

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