Receding Contact Angle Measurement via Dynamic Droplet Deposition

The patent employs periodic droplet deposition to dynamically establish the receding contact angle. Multiple droplets are deposited at controlled intervals, allowing the liquid drop perimeter to advance and retract repeatedly. This periodic action enables the system to capture the receding angle during the retraction phase, significantly reducing measurement time compared to static deposition methods while maintaining accuracy.

The patent transitions from static liquid drop placement to dynamic droplet deposition. By controlling the timing and energy of each droplet impact, the system creates a dynamic process where the liquid drop perimeter naturally advances and retracts. This dynamic approach allows the receding contact angle to be measured during the retraction phase, reducing the time required compared to traditional static methods.

The patent implements a self-service measurement system where the liquid drop itself generates the necessary dynamics through periodic droplet deposition. The system automatically captures images during the retraction phase and calculates the receding contact angle without requiring manual intervention or complex external equipment. The liquid drop's own behavior under controlled droplet impact provides the measurement signal, eliminating the need for complex external actuation mechanisms.

The patent replaces complex mechanical measurement systems (such as the Wilhelmy balance requiring force measurement and delicate balance manipulation) with a simpler imaging-based system. By using high-speed cameras to capture the liquid drop perimeter during retraction and computationally determining the contact angle, the system eliminates complex mechanical components while maintaining measurement reliability and improving ease of operation.

The patent uses periodic droplet deposition to rapidly establish the liquid drop and its receding contact angle. Multiple droplets are deposited at controlled intervals, creating a dynamic process that quickly reaches the measurement phase. This periodic action allows the system to capture the receding angle during the retraction phase, significantly increasing measurement speed while maintaining accuracy through automated image analysis.

The patent maintains continuous useful action by keeping the liquid drop on the surface throughout the measurement process. Rather than forming the drop and then removing it, the system maintains the drop in place while periodically impacting it with smaller droplets to induce retraction. This continuous presence allows for rapid sequential measurements without the time loss associated with repeated drop placement and removal, significantly improving productivity.