Photo-induced liquid-based slippery materials for highly efficient particle aggregation

The drying of droplets containing non-volatile solutes presents significant potential for sensing applications, including disease diagnosis, and the detection of harmful substances. Colloidal droplets form various patterns on surfaces after evaporation, and controlling the deposited patterns to achieve the desired characteristics is crucial in sensing applications. In this study, we propose a novel approach that employs a slippery organogel (SOG) surface that can be rapidly fabricated based on a photo-induced process to enhance the sensitivity and reproducibility during detection. The SOG forms a thin lubricating layer on the surface, which reduces the pinning of the three-phase contact line, causing the aggregation of particles within a confined area. To analyze the aggregation characteristics of colloidal droplets on the SOG, we compared the deposited particles after evaporating four types of colloidal droplets on the following different surfaces: hydrophilic, hydrophobic, organogel (OG), and SOG. The SOG surface demonstrated a superior particle aggregation capability across various colloidal droplets, which is crucial for the future development of high-sensitivity detection technologies.