Drying of a 75μL droplet of 25% poly(ethylene oxide) solution in water. The duration of the experiment was approximately 2 hours, the distance...
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Drying of a 75μL droplet of 25% poly(ethylene oxide) solution in water. The duration of the experiment was approximately 2 hours, the distance across the image approximately 10mm. Timings given below are given relative to the video, to aid identification of the various stages and processes.
The droplet exhibits stage 1 pinned drying for the first 5 seconds. However, the solid deposit is already much thicker for this droplet, than those with lower concentration. As the contact angle is increasing (stage 2) deposition occurs simultaneously (stage 3). The maximum height is reached at 10 seconds from which point, late stage drying (stage 4) accounts for the slow decrease in height. The final cone has half the base radius of the initial droplet.
