Tunable Periodic Surface Patterns by Drying Colloidal Suspensions under Intermittent Airflow: Toward Functional Material Design

Evaporation-driven patterning provides a straightforward and versatile strategy to create periodic surface structures relevant to applications in optics, printed electronics, and functional coatings. This study presents a user-friendly evaporative method for assembling such structures from colloidal suspensions, by periodically modulating the evaporation rate through time-controlled airflow cycles alternating between high and low phases. This modulation enables controlled advance and arrest of the drying front, promoting particle accumulation at the front and leading to the formation of long-range periodic arrays with tunable period and amplitude. The method is demonstrated using aqueous suspensions of polystyrene (PS), poly(butyl acrylate) (PBA), and their blends, with variations in composition and ionic strength enabling fine-tuning of the pattern characteristics. This approach offers a scalable and adaptable fabrication route for the design of functional materials.