Estimation of inhomogeneous zeta potential in the electroosmotic flow using a moving sensor

A method is devised to estimate the zeta potential profile along the microchannel wall using velocity measurements of the electroosmotic flow. The inverse problem is posed as a minimization problem of the performance function, which is the sum of square residuals between calculated and observed velocity, by means of a conjugate gradient method. One novelty of the present method is the adoption of a single moving sensor instead of several fixed sensors, which is moving at a given frequency near the microchannel wall. The present method estimates the zeta potential profile accurately without a priori information about the unknown function to be estimated.