Interactions between Colloids Induced by a Soft Cross-Linked Polymer Substrate

Lorenzo Di Michele, Taiki Yanagishima, Anthony R. Brewer, Jurij Kotar, Erika Eiser, Seth Fraden
2011 Physical Review Letters  
Using video-microscopy imaging we demonstrate the existence of a short-ranged equilibrium attraction between heavy silica colloids diffusing on soft surfaces of cross-linked polymer gels. The inter-colloid potential can be tuned by changing the gel stiffness or by coating the colloids with a polymer layer. On sufficiently soft substrates, the interaction induced by the polymer matrix leads to large-scale colloidal aggregation. We correlate the in-plane interaction with a colloid-surface attraction.
doi:10.1103/physrevlett.107.136101 pmid:22026874 fatcat:xq4rgkgevzdxhh7oylsc52keeq