Precise, fully automatic tilting table for the Drop Shape Analyzer – DSA25

Roll-off angle and dynamic contact angle measurements for drops on any solid

We have developed a new solution for our Drop Shape Analyzer – DSA25 which allows researchers to measure the contact angle on an inclined surface and the roll-off angle. Capable of achieving an inclination of up to 90°, the software-controlled tilting mechanism holds the entire measuring instrument, which can be mounted in just a few easy steps. The system is ideal for studying liquid adhesion on solid materials and de-wetting behavior in applications such as characterizing rough or hydrophobic materials.

Fully automated measurements of advancing and receding angles

Our ADVANCE – Drop Shape software performs drop shape analyses on an inclined solid surface with a rapid sequence of images or by recording a video for later evaluation. Using automatic analysis procedures that are easy to create, each of these options can be coupled to the start of the tilting motion. One especially informative measurement is a fully automated contact angle determination on drops as they slide across the inclined surface – i.e., when the sample is wetted in the direction of motion and de-wetted on the other side of the drop. This analysis yields simultaneous results for the advancing and receding angle, providing information on sample roughness, among other characteristics.

Objective parameters for determining the roll-off angle

The tilting table and our software also represent smart solutions for determining the roll-off angle, a parameter used for characterizing hydrophobic samples. The roll-off angle corresponds to the angle of surface inclination at the moment the drop changes its position and slides or rolls off the surface. To determine this parameter precisely, the software establishes the coordinates of the three-phase points, which indicate the position of the drop in the camera image. The change in these coordinates can be measured accurately, yielding an objective criterion for detecting the roll-off angle. The option of using a very slow rate of tilting (0.1 °/s) ensures that the analysis can be performed at a high level of precision.