Volume-19 (05/2008)

The Effect of an Oxygen-Helium Atmospheric Plasma on the Surface Energy of Medical Plastics

Many plastics possess physical properties that are desirable to the medical industry. By allowing these medical plastics to bond well with other plastics or materials of interest, more convenient and functional medical devices can be fabricated and applied. However, most polymeric materials or plastics do not bond well as they are typically very hydrophobic (water contact angles ~90°) and have low surface energies (~30-50 mN/m). Atmospheric plasma surface treatments are useful for intentionally modifying organic (e.g. polymer, carbon fibres, etc.) or inorganic (e.g. metals, glass, etc.) substrates. By increasing the hydrophilic character and, ultimately, the surface energy of plastic substrates, the adhesive strength can be significantly improved when bonded with particular adhesives.

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Practical contact angle measurement (4) - Measuring with method – but with which one?

For computer-supported drop shape analysis mathematical models are used which describe the optically determined shape. The DSA software from KRÜSS provides various methods with different application and validity ranges for this. This fourth part on practical contact angle measurement gives an overview of the methods and mentions the criteria for selecting the most suitable method.

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