Apparatus, methods, and fluid compositions for electrostatically-driven solvent ejection or particle formation

摘要

A method comprises introducing a fluid composition into one or more electrically insulating emitters, and applying voltage to the fluid to cause ejection of the solvent from the fluid after it exits the emitter. The fluid composition comprises first material having a dielectric constant greater than ˜25 and polymer mixed into liquid solvent having a dielectric constant less than ˜15, or polymer mixed into solvent having a dielectric constant greater than ˜8. Voltage can be applied to the fluid composition via a conductive electrode immersed in the fluid, or positioned outside and adjacent to the emitters. Conductivity of the fluid composition can be less than ˜100 μS/cm. A composition of matter comprises nanofibers formed by the method.

主权项

1. A method comprising:
introducing a fluid composition into one or more emitters, wherein (i) each emitter comprises an electrically insulating material and has a corresponding emitter orifice, (ii) the fluid composition comprises a first material having a dielectric constant greater than about 25 mixed into a liquid solvent having a dielectric constant less than about 15, (iii) the fluid composition further comprises a polymer dissolved, emulsified, or dispersed in the liquid solvent, and (iv) conductivity of the fluid composition is less than about 1 mS/cm; applying a voltage to the fluid composition to cause non-evaporative ejection of the solvent from the fluid composition after the fluid composition exits the emitters through the corresponding emitter orifices; and collecting polymer particles, formed by ejection of the solvent from the fluid composition, on a collection surface, wherein the collected polymer particles comprise polymer fibers, wherein the fluid composition that exits the emitter orifice forms one or more discrete fluid jets, and each jet ejects solvent and breaks up within about 3 mm of its corresponding point of formation.