Using Soap Slime to Assemble Particles into Networks

Note: Vehicle leaves for NCBS at 3.15 pm from the parking bay in front of the main library in IISc  and at 5.20 pm from NCBS to IISc.

At high concentrations of surfactant, for example, the slimy stuff at the bottom of a soap bar left on a wet sink, we observe phases with complex microstructures.  These include bilayer lamellar phases, as well as hexagonal or cubic phases.  In my talk, I will explore what happens when nanoparticles are added to a hexagonal phase. The hexagonal phase is liquid crystalline - viz. the rod-like surfactant assemblies have a preferred orientation.  We show that particles added to the hexagonal phase, segregate to domain boundaries and form three dimensional, networks.  We demonstrate that it is possible to crosslink such particles to form a free standing network. This self assembly of particles is independent of particle size (for particles that are greater than 10 nm), and does not depend on particle chemistry.  We show that gold particles can be assembled to form nanophotonic structures, that hydroxyapatite scaffolds can be produced for possible biomedical applications, and that even ferritin can be assembled into three-dimensional structures using this route.  Thus, inorganic, organic and biological structures can be assembled.  Our technique also allow us to control the orientation of the network and the inter-strand spacing in this network in a facile manner, and removal of the template surfactant is achieved using a simple water wash.  Thus, assembly of particles in a surfactant phase appears to be general route to forming macroporous materials from nanoparticles.

Host: Prof. Veronica Rodrigues ( veronica@ncbs.res.in )
Dr. Shachi Gosavi ( shachi@ncbs.res.in ) will introduce the speaker.

Please join for high tea and discussions at the Hortus Malabaricus Gardens.