Motion analysis of self-propelled Pt-silica particles in hydrogen peroxide solutions

Silica microspheres that are half-coated with platinum metal undergo self-propulsion in solutions of H(2)O(2), with the average speed increasing with increasing H(2)O(2) concentration. Microscopic observation of the particle motion, with segmentation of the image data, demonstrates that the particles move, on average, with the platinum-coated region oriented opposite to the direction of motion. Velocity autocorrelation and motion direction analyses show that the direction of motion is highly correlated with the particle orientation. The effect of the observation time interval on the measured translational diffusion coefficient and the apparent particle motion is analyzed.