Good adhesion is generally required whenever a coating is applied to a surface. In addition to a common case of painting, for example, adhesion is important in many industrial processes as well. Many products are composed of layers of different materials that all have specific function in a final product. For example, a milk carton is composed of layers of paper and polymer films and electronic sensor is a complex device with altering conductive and insulation layers. In order to these products fulfill their function, good adhesion between different layers is required. So, what are the requirements for good adhesion?
The most common reasons for adhesion failure are contamination. Any type of grease, oil or other impurities on the surface can cause the loss of adhesion. Making sure that the cleaning protocols are in place in your process is one of the most important things to ensure successful manufacturing. One way to determine the cleanliness of the surface is through contact angle measurements. As the contamination is often non-polar by nature, the contact angle of water on the unclean surface is higher than on a clean surface.
Drop of water on (left) Clean glass surface (right) dirty glass surface
Apart from cleaning the surface, some type of surface treatment may also be required to ensure good bonding between the two layers. One of the most used surface treatments is plasma treatment. In addition to providing an extra cleaning step for the surface, it will also improve the wettability of the substrate through the introduction of hydroxyl-, carboxyl and/or amine groups. Good surface wettability is prerequisite to good adhesion.
Water contact angle measurements can again be used to evaluate the impact of selected surface treatment method. To read more how contact angle measurements have been utilized in industrial processes, please download the review below.
Work of adhesion is defined as a work required to separate two phases from each other.
Adhesion plays an important role in daily and industrial processes. Adhesion can be either wanted or unwanted.
Adhesion is the attraction between two dissimilar phases. It is commonly divided into mechanical interlocking and physical and chemical bonding.
Coatings are typically evaluated by methods such as laboratory drawdown. Contact angle measurement can provide a more quantitative approach.
While contact angle goniometry has been around for many years, we have recently developed a way to account for the underlying surface’s micro-scale roughness.
Marine mussels are unbeatable when it comes to underwater adhesive strategies. They can attach to virtually all surfaces, tenaciously sustaining their bonds in saltwater and turbulent wave-swept conditions.
Wood-plastic composites are relatively new materials as they started to emerge at the beginning of the 90’s. The most widespread use of WCPs is in outdoor decking but it is also used in railings and siding as well as park benches and indoor furniture.
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