Droplet electrohydrodynamic

Zeng J, Korsmeyer T (2004) Principles of droplet electrohydrodynamics for lab-on-a-chip. Lab Chip 4 265-277... 

Electrohydrodynamic ionization A process in which a high voltage is used to generate droplets from which ions are desorbed under conditions of high... 

Electrospray, also called electrohydrodynamic or electrostatic spray, is an atomization technique in which liquids are dispersed solely by the application of high voltages. A simple electrospray setup is shown in Fig. 4. A liquid flows into a metal capillary tube charged to the kilovolt range and emerges from the tip as a conical meniscus, known as a Taylor cone, due to the intense electric field (Fig. 5). An unstable jet extends continuously from the apex of the cone and disperses into charged droplets further downstream. Electrosprays have been used in industrial... 

When the repnlsive forces dne to the snrface charges exceed the forces due to surface tension, the droplets explode as a result of field-induced Rayleigh or electrohydrodynamic instabilities. Mnltiple smaller droplets are generated. 

Dne to repetitive electrohydrodynamic instabihties, microdroplets containing only one charged molecule may be generated. By soft desolvation of this droplet, the ions will be free in the gas phase and amenable to mass analysis. 

In the ion-evaporation model of Iribame and Thomson [11-14], the seqnence of solvent evaporation and electrohydrodynamic droplet disintegration also leads to the production of microdroplets. Gas-phase ions can be generated from the highly-charged microdroplets, at which the local field strength is sufficiently high to allow preformed ions in solution to be emitted into the gas phase (lEV). 

There has recently been some interest in nanoflow LC as a mean of normalizing the mass spectrometric response [55-58], Nanospray is more than simply a reduction of ESI flow rate. ESI is an electrohydrodynamic process, with daughter droplets generated when Columb repulsion in a charged liquid (the parent droplet) overcomes... 

When a voltage is applied across adjacent electrodes (in the pattern shown in Figure 12.1) at 1000 Hz, 250 VRMS, liquid droplets quickly center themselves over the inter-electrode gap. Electrohydrodynamic forces act as an efficient mixer in such a system. 

Kim S, Song Y, Skipper P, Han J (2006) Electrohydrodynamic generation and delivery of monodisperse picoliter droplets using a poly (dimethylsiloxane) microchip. Anal Chem 78(23) 8011-8019... 

Electrohydrodynamic atomizers are used to make monodisperse aerosols of liquid droplets. A hquid is sprayed from a nozzle in the presence of an electric... 

Abstract This chapter provides information on different types of drop-on-demand drop generators. It starts with thermal or bubble jets, in which a nucleation bubble is used to eject a droplet out of an orifice. This is followed by piezoelectric, pneumatic, microfluidic, electrohydrodynamics (EHD) and aerodynamic droplet generators. For each droplet generator, the principle of operation and major features and characteristics are described. 

Keywords Droplet-on-demand (DOD) droplet generators Electrohydrodynamics (EHD) droplet generators Microfluidic droplet generators Piezoelectric droplet generators Pneumatic droplet generators Thermal or bubble jet droplet generators... 

J. M. Crowley Electrohydrodynamic droplet generators. Journal of Electrostatics, 14,... 

Keywords Aerodynamic effects Charged droplets Cone jet Droplet evaporation Droplet deformation Electrohydrodynamic spray Electrospray Ion source Mass spectrometry Mass spectroscopy Rayleigh charge limit Spray modes Taylor cone... 

Krohn, V. E. (1973). Evidence that the minimum-energy state is not accessible to a system of droplets produced by electrohydrodynamic spiaymg. Applied Physics Letters, Vol. 23 (5), 220. 

Electrohydrodynamic jet printing has become a high-resoluUon alternative to other forms of nozzle deposition-based methods. Microscale liquid droplets are generated by a large electrical voltage between the nozzle and substrate. 

Inkjet printing technology can be used with an electrohydrodynamic spraying technique (24). A conventional electrohydrodynamic inkjet device is based on DC voltage and requires two electrodes a nozzle electrode and an extractor electrode. However, this device suffers from drawbacks such as electrical breakdown. A more stable jetting technique uses the extractor electrode alone without the nozzle electrode and AC voltage. Thus, a continuous ejection of droplets can be obtained due to AC voltage. 

---