(489j) Buckling of a Drying Drop of Colloidal Dispersion: Experiments
AIChE Annual Meeting
Wednesday, November 16, 2022 - 2:45pm to 3:00pm
We performed experiments where drops of dispersions, containing colloidal particles of varying size and shear modulus were dried at elevated temperatures (80-160°C) and under vacuum. The drops were placed on superhydrophobic surfaces so as to maintain a spherical geometry throughout the drying process. The high drying rates led to the formation of a particle shell at the periphery of the drop. With continued evaporation, the drops shrink causing compressive stress in the particle shell. We observed that large drops buckled on drying while smaller drops retained their spherical shape. Further, for a fixed drop size, shells made of smaller particles buckled while those containing large particles remained spherical. The experimental results compared favorably with model predictions for different particle sizes and drop volumes.
The attached figure shows scanning electron microscopy images of (a) a buckled shell formed from a colloidal dispersion containing 1Î¼m polystyrene particles, and (b) an unbuckled shell formed from a colloidal dispersion containing 15Î¼m polystyrene particles
1. M. R. Lauro, C. Carbone, F. Sansone, B. Ruozi, R. Chillemi, S. Sciuto, R. P. Aquino and G. Puglisi, Drug Dev. Ind. Pharm., 2016, 42, 1127â1136.
2. L. Chen, T. Okuda, X.-Y. Lu and H.-K. Chan, Adv. Drug Delivery Rev., 2016, 100, 102â115.
3. A. Al Harraq and B. Bharti, Soft Matter, 2020, 16, 9643-9647