Droplet formation in matrix-assisted pulsed-laser evaporation direct writing of glycerol-water solution

Matrix-assisted pulsed-laser evaporation direct-write (MAPLE DW) is emerging as a promising technique for printing microelectronics as well as fabricating biological constructs. For disparate MAPLE DW-based microfabrication applications, the droplet formation during MAPLE DW should be first carefully understood. Toward this goal, this study aims to study the effects of laser fluence and material properties of material to be transferred on the formed droplet in direct writing glycerol-water droplets using MAPLE DW. It was found that (1) at a given glycerol concentration ratio, the droplet diameter was linearly dependent on the laser fluence, and the slope of this relationship was dependent on the glycerol concentration, and (2) the droplet diameter had no systematic relationship with the glycerol concentration ratio. This study reveals important phenomena for droplet formation in MAPLE DW; further theoretical modeling is expected to further explain these observations.