Professor Matthew Helgeson
Department of Chemical Engineering
University of California, Santa Barbara
Equilibrium self-assembly of molecular mesophases has long provided a platform for templating both organic and inorganic nanostructured materials including nanoparticles and mesoporous materials. However, thermodynamic equilibrium limits the window of material chemistries available to templating in mesophases, and surface energy considerations limit structuring to length scales less than tens of nanometers. This presentation will highlight our progress toward the development of self-assembling nanoemulsions as alternative non-equilibrium colloidal systems that break these constraints, whereby nanodroplets are used as fundamental building blocks for assembly of higher-order structures. In these nanoemulsions, droplet assembly is controlled by stimuli-responsive polymers that bridge between hydrophobic surfaces, providing tunable attractions that retain the individuality of droplets. These attractions can be used to form networks of droplets with a range of different structures through colloidal gelation and arrested phase separation, and the dynamics of structure evolution can be controlled in order to rationally engineer the features of the final assembled structure. The presentation will conclude with a number of demonstrations of how we can use the interesting properties of self-assembling nanoemulsions to create structured particles and materials.
Matt Helgeson is an Assistant Professor in the Department of Chemical Engineering at the University of California, Santa Barbara. He received his B.S. in Chemical Engineering from Carnegie Mellon University, and his Ph.D. in Chemical Engineering from the University of Delaware. Before joining UCSB in 2012, he was a postdoctoral associate in the MIT-Novartis Center for Continuous Pharmaceutical Manufacturing. Prof. Helgeson’s research focuses on understanding the colloidal behavior and rheology of nanoparticles, emulsions and proteins in self-assembling liquids, including the development of optical and scattering-based techniques for characterizing their structure and dynamics. His group’s current interests are aimed at harnessing the nanoscale behavior of these materials to design multi-functional particulates and gels for nanomaterial synthesis, biotechnology and energy conversion. Recent awards include the Victor K. LaMer award from the ACS Division of Colloid and Surface Science, the Neutron Scattering Society of America prize for Outstanding Research, the inaugural Distinguished Young Rheologist Award from TA Instruments, and a National Science Foundation CAREER Award.