Levich Institute Seminar Announcement, 10/05/2010
Tuesday, 10/05/2010
2:00 PM
Steinman Hall, Room #312
(Chemical Engineering Conference Room)

Professor Fernando Escobedo
Cornell University
School of Chemical and Biomolecular Engineering

"Mesoscopic Simulations of Order Disorder Transitions and Self-Assembly in Colloidal and Polymeric Systems"


ABSTRACT


Both colloidal particles and polymers often form ordered mesophases that posses unique optical, rheological, and mechanical properties, making them attractive components in the preparation of, e.g., novel solvent-free nanoparticle suspensions and photovoltaic materials. Our group employs molecular simulations to map out the still uncharted phase behavior of systems containing such building blocks. In this talk, I will discuss simulation results on suspensions of polyhedral particles and on blends containing diblock copolymers. In the system of space-filling polyhedral particles, simulations predict the formation of various novel liquid- and plastic-crystalline phases at intermediate volume fractions. These results show that high order of rotational symmetry is in general conducive to mesophase formation, with low anisotropy favoring plastic-solid behavior and intermediate anisotropy favoring liquid crystalline behavior. In the diblock copolymer we focus on optimizing the system’s composition (associated with chain bidispersity or a homopolymer additive) to target the formation of the often elusive bi-continuous phases. Our results elucidate the origins of the packing frustration and demonstrate how such ordered phases result from maximizing the entropy of the additive.

BRIEF ACADEMIC/EMPLOYMENT HISTORY

  • Full Professor, CBE, Cornell University, 04/10 – Present
  • Associate Professor, Cornell University, 11/04 – 03/10.
  • Assistant Professor, Cornell University, 01/99 – 10/04.
  • Research & Development Engineer, Abrasivos Industriales S.A., Peru, 08/87 – 08/91.
  • Ph.D. in Chemical Engineering, University of Wisconsin-Madison (08/93 - 08/97).
  • M.S. in Chemical Engineering, University of Nebraska-Lincoln (08/91 – 08/93).
  • B.S. in Chemical Engineering, Universidad de San Agustin Peru (08/81-05/86).

RECENT RESEARCH INTERESTS

Complex ordered structures in diblock copolymers; Entropy-driven selft-assembly of nano- and micro-particles of unusual shapes; Reassembly of protein fragments; Structure and binding of Nanobodies