Shape Changes of Colloidal Suspension Droplets during Drying

(Received 15 December 1995, received in final form 27 February 1996, accepted 19 March 1996)

Abstract
We have investigated the drying of colloidal suspension drops deposited onto a flat substrate and the thickness of the resulting solid film. To explain the complex dynamics of the drop shape, we have developed two models based on simplified descriptions of the drop geometry during the drying. The first uses the assumption of a constant contact angle and the second the assumption of a constant contact base. The results have been compared to experimental measurements of the drop profile recorded at different times of drying. In particular, we find that the constant contact base model allows a good description of the final thickness of the deposited film under a large variety of experimental conditions.