Depletion versus stabilization induced by polymers and nanoparticles: The state of the art

The entropic depletion interaction has been the subject of several studies over the past decade because it plays an important role in many industrial applications and also involves in controlling biological interactions. In this short review, we discuss recent developments associated with using nonintrusive optical techniques for directly measuring k(B)T-scale depletion interaction. In particular, we limit the scope of this review to the use of total internal reflection microscopy (TIRM) for quantitative measurements of interactions between a single, colloidal particle and a flat surface mediated by the presence of neutral polymers, polyelectrolytes, and charged nanoparticles with different softness based on our recent works. Finally, we conclude with some perspectives on future research efforts in this field. (C) 2014 Elsevier Ltd. All rights reserved.