Loss-Free Photo-Manipulation of Droplets by Pyroelectro-Trapping on Superhydrophobic Surfaces.

Manipulation of tiny amounts of liquid is a fundamental technique for miniaturized diagnostic, analyzing, and synthetic processes. Among diverse maneuver methods, light-controlled liquid manipulation stands out because of its ready controllability, high spatial precision, and noncontact feature of light. As light controls the motion of liquid droplets, substantial liquid loss frequently accompanies, leading to reduced sample volume, contaminated devices, and erroneous results. Here, we report a light-controlled droplet-maneuver method based on pyroelectro-trapping on superhydrophobic surfaces. On such a platform, a light source traps and guides the droplet on a nonwetting surface remotely, offering a precise and loss-free droplet transport that eliminates intersample cross-contaminations. Our approach provides a simplified, facile, and compact platform which is suitable for repeated and multistep usages. Droplet-based microreactions and enhanced mixing inside tiny droplets are effectively demonstrated using the platform. The photocontrolled loss-free droplet maneuver is very promising for applications like chemical/bioassays, microfluidics, and liquid transfer.