ABSTRACT: A central area of research in the soft matter community is in inorganic/organic hybrid materials with nanoscale inorganic particles. These materials have been focused on due to their promise of having synergistic thermal, mechanical and optical properties relative to the pure materials. It is now accepted that the spatial distribution of the inorganic nanoparticles critically affect the properties of the resulting materials, but a grand challenge is to control the spatial distribution of the inorganic, hydrophilic nanoparticles in the organic, hydrophobic polymer matrix. I focus on one particular approach to controlling nanoparticle spatial dispersion, the use of polymer-grafted nanoparticles. In the case where the NP and the grafted polymer chains energetically “dislike” each other, we have an architecture akin to a microphase separated block copolymer or a surfactant. Analogous to these “surfactants” these grafted nanoparticles also assemble into a range of morphologies, thus giving us the unprecedented ability to control the particle dispersion state.
In this talk I first focus on the factors controlling this assembly and use this knowledge to consider the utility of other approaches to self-assembly – we show that the use of crystallizable polymers allows us to control nanoparticle order, in particular by varying the rate at which these materials crystallize. This allows us to mimic the growth of organisms such as nacre and oysters, whose shells combine the dual advantages of high strength and toughness. In a different vein, these grafted nanoparticles show the ability to creating membranes that have the potential to revolutionize the separation of hydrocarbons and in carbon sequestration.
BIO: Sanat K. Kumar is the distinguished Bykhovsky Professor in the Department of Chemical Engineering at Columbia University. Previously, he was the Chair of the Department of Chemical Engineering at Columbia from 2010 to 2016. He earned his B.Tech in Chemical Engineering from the Indian Institute of Technology, and his S.M. and Sc.D in Chemical Engineering from MIT. His primary research interests include synthetic- and bio-polymers, nano-composites and nano-materials.
Hosted by Laura Fabris, Ph.D.