Details

Autor(en) / Beteiligte

• Mandsberg, Nikolaj K.
• Shneidman, Anna V.
• Jensen, Kaare H.
• Taboryski, Rafael
• Nielsen, Line H.
• Aizenberg, Joanna
• Boisen, Anja

Titel

Gradient Droplet Arrays by Acceleration‐Mode Dip‐Coating

Ist Teil von

• Advanced materials interfaces, 2022-08, Vol.9 (22), p.n/a

Ort / Verlag

Weinheim: John Wiley & Sons, Inc

Erscheinungsjahr

2022

Quelle

Wiley Online Library All Journals

Beschreibungen/Notizen

• Droplet microarray technology is of great interest in biology and chemistry as it allows for significant reactant savings and massive parallelization of experiments. Upon scaling down the footprint of each droplet in an array, it becomes increasingly challenging to produce the array drop‐by‐drop. Therefore, techniques for parallelized droplet production are developed, e.g., dip‐coating of biphilic substrates. However, it is in general difficult to tailor the characteristics of individual droplets, such as size and content, without updating the substrate. Here, the method of dip‐coating of uniformly patterned biphilic substrates in so‐called “acceleration‐mode” to produce droplet arrays featuring gradients in droplet height for fixed droplet footprint is developed. The results herein present this method applied to produce drops with base diameters varying over orders of magnitude, from as high as 6 mm to as small as 50 µm; importantly, the experimentally measured power‐law‐dependency of volume on capillary‐number matches analytical theory for droplet formation on heterogenous substrates though the precise quantitative values likely differ due to 2D substrate patterning. Gradient characteristics, including average droplet volume, steepness of the gradient, and its monotonicity, can all be tuned by changing the dip‐coating parameters, thus providing a robust method for high‐throughput screening applications and experiments. Droplet arrays are rapidly formed through dip‐coating of biphilic substrates. Meanwhile, dip‐coating of unpatterned substrates in acceleration‐mode leads to thickness gradients across the resulting film coating. The combination of these two concepts allows for generating droplet arrays featuring tunable gradients in volume for droplet base diameters ranging from as large as 6 mm to as small as 50 µm.