Droplet Delivery Control for Surface Acoustic Wave Nebulization Mass Spectrometry

We present a novel atomizer using standing wave type surface acoustic wave nebulization (SAWN). Compared with progressive wave SAWN, the standing wave SAWN creates smaller drop sizes. We integrate droplet delivery control functionality with anisotropic ratchet conveyors (ARC) on top of the SAWN surface, which employs micro-sized hydrophilic patterns on hydrophobic Cytop coatings. By adopting Parylene-C as a stencil mask, the hydrophobicity of Cytop does not degrade during fabrication. Droplet movement, merging, mixing and nebulizing are demonstrated as a lab-on-chip platform.