SHAPE CHANGES OF COLLOIDAL SUSPENSION DROPLETS DURING DRYING

We have investigated the drying of colloidal suspension drops deposite d onto a fiat 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 durin g the drying. The first uses the assumption of a constant contact angl e and the second the assumption of a constant contact base. The result s 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 th ickness of the deposited film under a large variety of experimental co nditions.