Optofluidic Platform for the Manipulation of Water Droplets on Engineered LiNbO₃ Surfaces.

Zaltron, Annamaria; Ferraro, Davide; Meggiolaro, Alessio; Cremaschini, Sebastian; Carneri, Mattia; Chiarello, Enrico; Sartori, Paolo; Pierno, Matteo; Sada, Cinzia; Mistura, Giampaolo

The actuation and control of liquid droplets on a surface have important implications in many industrial applications and microfluidics. In recent years, various strategies have been used. Here, an optofluidic platform that performs the basic droplet handling operations required in a common microfluidic device is presented. It is based on z‐cut, iron‐doped lithium niobate crystals that, when illuminated, generate surface charges of opposite sign at the two crystal faces because of the photovoltaic effect. The face of the crystal in contact with the droplets is coated with a lubricant‐infused layer, which guarantees hydrophobicity and, more importantly, a very slippery and robust surface for prolonged use. In this way, sessile water droplets having volumes of microliters, corresponding to millimeters in size, can be easily actuated, guided, merged, and split by projection on the crystal of suitable static or dynamic light patterns. The actuated droplets can cover distances of centimeters on a timescale of a few seconds. The resulting platform is highly flexible and reconfigurable and does not require moving parts.

PHOTOVOLTAIC effect; DROPLETS; MICROFLUIDIC devices; SURFACE charges; LITHIUM niobate; FLUIDIC devices; LIQUID surfaces; MICROFLUIDICS

Advanced Materials Interfaces, 2022, Vol 9, Issue 22, p1

2196-7350

Academic Journal

10.1002/admi.202200345