Computational Science Center Seminar
"Colloidal particles at liquid interfaces and thin films:"
Presented by Carlos Colosqui, SBU
Friday, November 8, 2013, 1 pm
John Dunn Seminar Room, Bldg. 463
Hosted by: Robert Harrison
Numerous natural and industrial processes involve adsorption of (nano and microscale) colloidal particles at liquid interfaces and diverse self-assembly processes. Standard models based on continuum thermodynamics predict a rapid exponential relaxation to stable equilibrium states where the system free energy is minimized. However, the dynamics of adsorption and assembly can present nontrivial aspects that emerge in the presence of metastable states associated with local minima of the free energy. Recent experimental observations of the adsorption of microparticles documented a slow logarithmic relaxation that resembles "physical aging"' in glasses and amorphous materials. The first part of this talk deals with the dynamics of adsorption of single particles. I will present theoretical work and molecular dynamics simulations [Colosqui, Morris, & Koplik, Phys. Rev. Lett. (2013)] establishing a clear connection between the time scales for the slow relaxation and microscale features on the particle surface. In the second part of this talk, I will present a recently proposed mechanism for the assembly of colloidal particles in thin coating films. Theoretical and numerical results [Colosqui, Morris, & Stone, Phys. Rev. Lett. (2013)] demonstrate a "hydrodynamically-driven"' assembly that can lead to spontaneous pattern formation and highly ordered colloidal crystals. These results indicate future directions for the flow-driven assembly of nanomaterials.