Surface-Charge Patterning Techniques

The surface-charge patterning technique is a surface chemistry process to make both... 

In microfluidic systems, liquid flow control is very challenging because of the large flow resistance. As such, electroosmotic flow (EOF), a surface-driven flow phenomenon, is an alternative to pressure-driven flow (PDF), in order to overcome the flow resistance problem. Since the velocity of EOF depends on the surface charge of the channel wall, the surface-charge patterning technique has thus been developed to control liquid flow in a very confined space. 

Surface-Charge Patterning Techniques, Fig. 3 Schematics of the setup for micromolding that creates polymer surface-charge pattern on a glass surface... 

The surface-charge patterning technique combined with EOF is, in principle, able to create numerous flow patterns at the microscale. In experiments, several simple flow patterns have... 

Surface-Charge Patterning Techniques, Fig. 4 Schematics of surface-charge patterning by the photolithography method, (a) A glass substrate with patterned photoresist is submerged in a polymer solution, (b)... 

Surface-Charge Patterning Techniques, Figure 1 (a) Schematic chemical structure of a glass (or silicon dioxide) surface, (b) Glass surface carries negative charges in contact with aqueous solution... 

Surface-Charge Patterning Techniques, Figure 5 (a) Schematic plan view of longitudinal (i. e. parallel to the electric field set up by the electrodes at both ends) surface-charge patterns in a microchannel which generates bi-directional shear flow, (b) A cross-section A-A of the microchannel showing symmetric patterns on top and bottom of the channel walls... 

---