Acoustic ejection of a dual-liquid layer

Acoustic ejection is used to displace small amounts of fluid using an ultrasound pulse impinging on a liquid-air interface. We extend this idea to a dual-liquid-air system to achieve simultaneous ejection of both liquids. The results show successful ejections of a dual-liquid layer with different top layer volumes and acoustic energies. This method could enable the creation of core-sheath/shell structures for different industrial or medical applications using acoustic ejection. Specific possible applications are core-sheath electrospinning, core-shell electrospraying and particle encapsulation.