A new process is presented where the controlled coagulation of droplets is
achieved through electrical forces. The charged droplets are produced by el
ectrosprays operated in the cone-jet mode. The coagulation of oppositely ch
arged droplets leads to the neutralization of the electrosprays. Furthermor
e, this coagulation enables controlled mixing on a microscale and subsequen
t chemical reactions inside the combined droplets. This process has many po
tential applications in the production of "tailored" particles, particles o
f uniform size and composition.