Abstract
As chemical processes are downscaled and integrated into micro/nano spaces, understanding near-wall ion transport with fluid flows becomes important due to dominant surface effects. This study therefore developed functionalized nanotracer particles for simultaneous measurements of fluid velocity and ion concentration in micro/nanofluidic channels. A method to modify two kinds of fluorescent material on polystyrene bead of 100-1000 nm diameters was established to achieve pH measurement from observed fluorescent color. The method was demonstrated in a mixing of two solutions of different pH by pressure driven flows, and velocity and pH distributions with fluid flow could be successfully obtained.