Abstract
We formulate microfluidic design principles for electrospray ionization sources based on a rectangular capillary slot formed by two triangular cantilevers. Spontaneous imbibition of the test liquids into the slot by capillary action provides a robust mechanism for liquid transport from a reservoir to the cantilever tip where an electrospray is generated upon application of a voltage. The correct functioning of the source requires the liquid bridging the slot to have a negative Laplace pressure. Imbibition is controlled by the ratio of slot width to height w∕h and the intrinsic contact angles θw, θs of the liquid with the slot walls and the cantilever faces, respectively. Based on these parameters we derive a simple criterion for the complete filling of the slot.
Original language | English |
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Pages (from-to) | 2140-2142 |
Journal | Applied Physics Letters |
Volume | 85 |
Issue number | 11 |
DOIs | |
Publication status | Published - 13 Sept 2004 |
Externally published | Yes |