INDUSTRY NEWS
How Smooth is Your Surface? Source: ATA Scientific
All surfaces, no matter how smooth they may appear, have a degree of roughness which can influence their wetting behaviour and therefore adhesion. Determining the most suitable roughness parameters and separating the impact of chemical and mechanical treatment on wettability can help reveal the mechanisms at play which can be useful in product development processes and in quality control. Applications • Biocompatibility of medical implants: Separating the impact of chemical and mechanical treatment on water contact value can be very useful in implant development and biocompatibility studies with the surrounding host tissue. • Paper and board coatings: Optimised wetting and adhesion of paper surfaces play a crucial role in ensuring quality and runnability in various operations such as printing and packaging. • Construction and building materials: Coating and surface finishing of construction and building materials are important for enhanced appearance and durability of the materials.
Technology - How does it work? Wettability, as determined through contact angle measurements, can indicate whether the surface is hydrophobic or hydrophilic. When the contact angle of the liquid is low, the surface is said to be more wettable when compared to a higher contact angle. For ideal materials, the surface is assumed to be chemically homogenous and topographically smooth. This is clearly, not true in the case of real surfaces. When surface roughness is added, the surface becomes even more hydrophobic (refer to Figure 1), as the liquid penetrates into the roughness grooves. Until now, contact angle and surface roughness have only been measured individually, by using an optical tensiometer and a separate roughness measurement instrument.
Theta Flow is the new Attension optical tensiometer that integrates a high level of automation to simplify measurements and increase accuracy. Together, these features make it the most user-independent contact angle meter. The new Attension Theta Flow Optical Tensiometer with 3D Topography Module (refer to Figure 2), makes it possible to combine 3D surface roughness measurements in conjunction with
Figure 2: Attension Theta Flow Optical Tensiometer with 3D Topography Module
contact angle measurements on exactly the same sample location. The fully automatic measurement takes only a few seconds while OneAttension software automatically calculates roughness corrected contact angle and surface free energy. This unique tool offers the ability to automatically evaluate the impact of surface chemistry and roughness of various coating formulations and surface modifications. With its high-end camera, image enhancement technology and built-in sensors, the Theta Flow tensiometer builds on the popular Theta Flex – - recent recipient of the 2020 Red Dot award for 2020 for its neat design and ease of use. Theta Flow’s autofocus function together with the DropletPlus image enhancer algorithm significantly improves the chances of accurate baseline placement, particularly for challenging samples. Theta Flow is ideal for measuring Static contact angle, Dynamic contact angle, Surface free energy, Surface- and interfacial tension, Roughnesscorrected contact angle and 3D surface roughness and Interfacial dilatational rheology. To celebrate the new release, we are offering a 10% discount on all Theta Flow systems for a limited time until the end of September 2021! Contact us and find out more about this one-time launch offer. ATA Scientific Pty Ltd +61 2 9541 3500 enquiries@atascientific.com.au www.atascientific.com.au
Figure 1: A. Contact angle on an ideal surface; B. Apparent or measured contact angle on a real surface.
32 | JUNE 2021
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Reference: Lauren, S. PhD. “The Attension Theta Flex Optical Tensiometer with 3D Topography Module”, Biolin Scientific. WWW.MATERIALSAUSTRALIA.COM.AU
