Surface inspection before coating or bonding

Bonding and coating are standard processes in the manufacturing of a multitude of products. Bonding is used to attach two materials for improved product performance while coating is applied to protect and finalize the surface of the product. The success is determined by the adhesion of the bond or coating as weak adhesion will, in the worst case, lead to the failure of the product. To ensure good adhesion, the wettability of the surface plays a pivotal role. The wettability of the surface should be inspected before bonding or coating. 

Cleaning and etching are used to modify the surface to be more hydrophilic 

To ensure good adhesion, the surface properties need to be optimized prior to bonding or coating. This is typically done by etching or cleaning the surface. The purpose of this is to prepare the surface for subsequent process steps. 

In cleaning, the contaminants are removed from the surface. Contaminants are typically hydrophobic, like grease, which would decrease the wettability of the surface. In addition, as the dirt is typically quite loosely bound to the surface, leaving it would lead to weak spots in the coating. 

Surface etching, on the other hand, is typically done for polymers to change their inherently hydrophobic surface to hydrophilic. Again this step aims to improve the wettability of the surface. 

Water contact angle measurement to determine surface properties

Water contact angle measurement is a fast method the check the quality of the surface. The droplet is placed on the sample surface and the angle is optically measured. Droplets can be created with the manual syringe or with automated dispensers. The entire measurement takes only a minute to conduct and will immediately show whether the surface is ready for the next process step. 

If you would like to learn more about contact angle measurements and how they can be used to predict adhesion, please watch the webinar through the link below.