Events

Dr. Lorenzo Botto, Colloidal assembly at fluid interfaces: capillarity, fluid flow, and contact line phenomena

Date: Wednesday 2 October 2013 13:30 - 14:30

Location: Nanoforce seminar room (Joseph Priestley Building)

The first talk of the SIMULATION & MODELLING SEMINAR will take place on Wednesday 2nd of October at 1.30 pm in Nano Force seminar room.

The talk will be given by one of our faculty members, Dr. Lorenzo Botto; for this particular time, and since the topic is highly interdisciplinary, the event will run jointly with the seminar of the MRI institute.

Colloidal assembly at fluid interfaces: capillarity, fluid flow, and contact line phenomena

Recently, there have been unprecedented advancements in the synthesis of complex shaped colloids and nanoparticles. Finding ways to assemble these building blocks is one of the key new challenges in materials research. This talk will describe recent work in the modeling of rod-like colloidal particles adsorbed at fluid-fluid interfaces – with specific focus on cylinders and ellipsoids. Because of their complex shape, anisotropic particles induce undulated contact lines and long-ranged interfacial distortions, leading to remarkably strong in-plane interactions driven by surface energy minimization. For interfacial colloids in the micron-size range, interaction energies are typically in excess of 10^6 kT. When present, shape-induced capillary interactions are among the strongest colloidal forces, and neglecting them can lead to unacceptable errors.

I will discuss how these colloidal interactions can be modeled, the structures they lead to on flat interfaces, and how they presence drastically affect deposition patterns in assembly processes exploiting fluid flow and moving contact lines. In addition to being applied to 2D surfaces, fluid interfaces can also be used for three-dimensional materials: the morphologically-complex interfaces of foams, emulsions, and other separated phases can be used as 3D templates, potentially expanding enormously the range of structures that can be produced by self- and directed colloidal assembly.

It will be of interest to people working in Simulations, Material, and Bioengineering, and in general to researchers and students interested in soft matter systems.

Dr. Botto is currently a Lecturer in Modelling and Simulation at SEMS. His research
interests span fluid mechanical aspects of suspension flows, rheologically-complex
fluids, and soft materials.

References
1. L. Botto, L. Yao, R. L. Leheny, K. J. Stebe., “Capillary bond between rod-like particles and the micromechanics of particle-laden interfaces”, Soft Matter, 8, 2012
2. L. Botto, E. P. Lewandowski, M. Cavallaro, Jr., and K. J. Stebe, “Capillary interactions between anisotropic particles”, Soft Matter 8, 9957, 2012
3. M. Cavallaro, Jr., L. Botto, E. P. Lewandowski, M. Wang, and K. J. Stebe, “Curvature-driven capillary migration and assembly of rod-like particles”, PNAS, 108, 20923, 2011