Abstract

Here we demonstrate the direct measurement of the interaction potential energy landscapes between colloidal nanoparticles and surfaces. Measurements are made with high-throughput by measuring the fluctuations in the height of the nanoparticles as they are propelled along an optical waveguide by the optical scattering force and held near the surface by the optical gradient force. This is accomplished by imaging the light scattered by the particles as they interact with the evanescent field using a high frame rate CMOS camera. These measurements characterize the strength of the potential energy barrier preventing nanoparticles from sticking, and therefore give insight into the colloidal stability. This can be performed on metallic, dielectric, and biological materials with diameters ranging from tens of nanometers to micrometers.

© 2016 Optical Society of America