Abstract
We propose new device to achieve both mixing and pumping fluid in microchannel simultaneously. Electroosmotic flow direction can be changed partly by replacing a part of wall material of microchannel, and it changes the flow pattern in the channel, leading to enhancement of mixture. Tow sorts of microchannels (with SiO_2 wall and Al_2O_3 wall) were fabricated and electroosmotic flows in these channels were measured. It was shown that flow direction of these channels is opposite under same electric field and electrolyte. According to the simulation, the mixture of fluid is conducted more efficiently by replacing the material of channel wall partly.
