title: Particle and substrate charge effects on colloidal self-assembly in a sessile drop.
abstract: By direct video monitoring of dynamic colloidal self-assembly during solvent evaporation in a sessile drop, we investigated the effect of surface charge on the ordering of colloidal spheres. The in situ observations revealed that the interaction between charged colloidal spheres and substrates affects the mobility of colloidal spheres during convective self-assembly, playing an important role in the colloidal crystal growth process. Both ordered and disordered growth was observed depending on different chemical conditions mediated by surface charge and surfactant additions to the sessile drop system. These different self-assembly behaviors were explained by the Coulombic and hydrophobic interactions between surface-charged colloidal spheres and substrates.
authors.affiliation: Singapore-MIT Alliance, N3.2-01-36, 65 Nanyang Drive, Singapore 637460.
authors.forename: Qingfeng
authors.initials: Q
authors.lastname: Yan
authors.forename: Li
authors.initials: L
authors.lastname: Gao
authors.forename: Vyom
authors.initials: V
authors.lastname: Sharma
authors.forename: Yet-Ming
authors.initials: YM
authors.lastname: Chiang
authors.forename: C C
authors.initials: CC
authors.lastname: Wong