Direct Measurement of Surface Forces for Nanoparticles

Abstract

The direct measurement of surface forces for nanoparticles is based on a modification of the colloid probe technique in an atomic force microscope. This technique has recently been developed by the authors. Here we present the impact of an adsorbed polymer layer on interparticle forces. Variation of the size of the colloid probe from micron to nano-size shows the impact of particle size on steric forces. Whereas interaction force for large particle decreased with a large amount of free polymer due to depletion effect, nanosize particles were less affected by depletion forces.