Precision Patterning of Superhydrophobic- Superhydrophilic Microdroplet Arrays: Towards On-Demand Sustainable Manufacturing of Functional Materials

Abstract

Surface wettability is an important phenomenon that has implications in many different scientific domains. It is determined by the interaction between liquids and solid substrates. This study investigates the production of superhydrophobic/superhydrophilic surfaces on aluminum alloy (Al 6061) by non- hazardous chemical treatments and nanosecond-pulse laser processing as an environmentally acceptable method of producing microdroplet arrays. The method used is discontinuous dewetting, which allows for accurate droplet generation without the need for costly automation. Process parameters are optimized to achieve effective water separation between superhydrophilic patterns, and the impact of laser power on water spreading is demonstrated. Surface chemistry and morphology are characterized at each stage of the fabrication process through various analyses. The fabricated surfaces exhibit reliable stability under long exposure to air, freshwater, and intense heat conditions. Additionally, the prospective of using disposable aluminum dishes to produce customizable superhydrophobic surfaces with superhydrophilic arrays is introduced. This eco-friendly approach addresses the need for higher array density platforms with small droplet volumes, particularly relevant for biomedical and pharmacological applications demanding high detection sensitivity and throughput processing.