Drying Kinetics of Polymer Solutions with and without Colloidal Particles

We investigated the drying rate (J) of polymer solutions with colloidal particles. Although such solutions are frequently used to produce commercial products, the number of studies on drying kinetics is limited. We used particles with two different diameters and three types of common polymers. A decrease in J started when the amount of polymer that is transported to the drying interface reached a critical threshold. The threshold was smaller, and the drying rate started to decrease much earlier for the polymer solutions with particles than for the pristine polymer solutions. We also found that time evolutions of J in various samples with different particle sizes, different polymers, and different drying conditions collapsed on a single curve after scaling the data based on the initial drying rate and the critical threshold of the polymer amount. The effects of colloidal particles on J and the mechanisms for the decrease in J are discussed.