Controlled Generation of Double Emulsions in Air

Abstract

This communication describes the controlled generation of double emulsions in the gas phase, which was carried out using an integrated emitter in a PDMS (poly(dimethylsiloxane)) microfluidic chip. The integrated emitter was formed using a molding approach, in which metal wires with desirable diameters were used as emitter molds. The generation of double emulsions in air was achieved with electrohydrodynamics actuation, which offers controllable force exerting on the double emulsions. We developed this capability for future integration of droplet microfluidics with mass spectrometry (MS), where each aqueous droplet in the microchannel is introduced into the gas phase as a double emulsion for subsequent ionization and MS analysis.

Nanoliter Segmented-Flow Sampling Mass Spectrometry with Online Compartmentalization

“…The system can be realized as a PDMS chip 22 or assembled from commercially available fused silica capillaries. A substantial improvement is the use of a volatile water-immiscible phase that avoids the need for removal of the oil phase from the microfluidics channel prior the ionization.…”

“…This combination allows for IR laser-assisted droplet evaporation in the rough vacuum region of the mass spectrometer and formation of gas-phase ions. Continuous streams of separated immiscible liquid phase compartments (water and fluorinated oil, Figure S1 in the Supporting Information ) are generated in a microfluidic device which was realized as a polydimethylsiloxane (PDMS) chip, 22 or a fused silica capillary T-junction. The stream is converted to droplets and flown into the vacuum system.…”

Time-Profile Measurement of an Emulsion Using Multiphoton Ionization Time-of-Flight Mass Spectrometry in Combination with a Microscope

“…1,2 Furthermore, multiple emulsions exist, such as a water-in-oil-inwater (W/O/W) emulsion and an oil-in-water-in-oil (O/W/O) emulsion, and new preparation techniques for controllable monodispersed multiple emulsions have recently been reported. 3,4 Emulsions are widely applied in academic fields: liquid-liquid extraction or dispersive liquid-liquid microextraction is often used in analytical chemistry [5][6][7][8][9][10] and emulsion polymerization is common in polymer chemistry. 11,12 Emulsions are also commonly used in practical applications, such as foods, drinks, and cosmetics.…”

Preparation of polyacrylonitrile- based porous hollow carbon microspheres

“…In order to avoid the influence of other molecules on pore structures such as the surfactant [15,17,[18][19][20], surfactant-free PAN solution was prepared. Besides, during the process of using T-junction microfludic device to obtain the PAN double emulsions, it was important to obey the rule of density matching.…”