The evaporation of a colloidal suspension drop pinned on a substrate usually results in a ring of particles accumulated at the initial drop periphery. Intense research has been devoted to understand, suppress and ultimately control this so-called Coffee-Ring Effect (CRE). Although the crucial role of flow patterns on the CRE has been thoroughly investigated, the effect of interactions on this phenomenon has been largely neglected. In this concept paper, we review recent works in this field and show that the interactions of colloids with (and at) liquid-solid and liquid-gas interfaces as well as bulk particle-particle interactions drastically affect the deposit morphology. We establish general rules to control the CRE by tuning these interactions, providing guidelines for the rational physicochemical formulation of colloidal suspensions capable of depositing particles into desirable patterns. This opens perspectives for the reliable control of the CRE in real-world formulations and creates new paradigms for flexible particle pattering at all kinds of interfaces as well for the exploitation of the CRE as a robust and inexpensive diagnostic tool.
Reference:
Reference:
Manipulating the Coffee-Ring Effect: Interactions at Work
M. Anyfantakis,* D. Baigl*
ChemPhysChem 2015, 16, 2726 – 2734
- doi : 10.1002/cphc.201500410