Photothermal‐Electric Excited Droplet Multibehavioral Manipulation

Abstract The light‐excited droplet manipulation is crucial in diverse industrial and health domains, owning to the merits of real‐time control and noncontact operation. However, strong driving forces and high‐precision maneuverability for splitting or mixing are still the challenges. Here a novel concept of configurating pyroelectric crystal surface is put forward to carry out multifunctional manipulation of the droplet by optical‐thermal‐electrical effect. Dipole‐like electric charge distribution is excited around the light spot to generate sharper inversion of electric field gradient and 10‐fold stronger dielectrophoretic （DEP） force than conventional photopyroelectric approaches. Both the stable mode and metastable‐oscillation mode are found and can be positively used to make on‐demand sliding and inside mixing of droplets. Especially, various droplets with the surface tension ranging from 25.7 to 85.4 mN m −1 can be split by light. The present droplet manipulation technique demonstrates its promising applications in cargo transportation, combinatorial chemistry and biomedical analysis.