Talks & Lectures
27 Mar 2019
Carnegie 315

A Modular 'Molecular Composite' Electrolyte Platform Based on a Double Helix Polyelectrolyte

Nanotechnology Seminar Series: Louis A. Madsen, Virginia Tech

Louis Madsen


Collective intermolecular interactions can give rise to surprising material properties. I will describe a new class of materials ‒ "molecular ionic composites" (MICs) ‒ which simultaneously possess high mechanical stiffness and yet free (liquid-like) motions of ions inside.

MICs show promise for enabling, e.g., high density and safe Li and Na batteries, as well as a host of other electrochemical and molecular separations devices. MICs consist of a collective electrostatic network that enables both fast ionic transport (conductivity up to 8 mS/cm) and stiff mechanical properties (E’ up to 3 GPa), and these materials are stable conductors from -50 to +300°C.

The figure below (MD simulation, looking down polymer rod axes) illustrates the extensive s. The sulfonated aramid (Kevlar-like) polyelectrolyte forms a double helix that provides a rigidity persistence length of ~ 1 micrometer along the rod axis (20X that of DNA).

ionic correlations present in molecular ionic composites


Louis Madsen grew up in Madison, WI, attended Grinnell College, obtained his Ph.D. at Caltech, and postdoc’ed at UNC Chapel Hill and Victoria University of Wellington, New Zealand, with pursuits in chemistry, physics and materials science. Since joining Virginia Tech, his research has focused on uncovering fundamental phenomena relating to multi-scale transport and structure in soft materials including fast ion conductors and polymeric drug delivery agents. New understanding of these systems is illuminating paths toward efficient energy storage/conversion, water purification, and nanomedicine. The lab is also developing a new class of composite electrolytes for advanced batteries and molecular separations.

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