Physics Colloquium: Block Polymer Nanostructures in Ionic Liquids: Stimuli Responsive and Functional Materials

Event Details

  • Speaker(s): Timothy P. Lodge
  • Date:
  • Time: 4:00 PM
  • Location: MacN 101

Abstract

Block polymers provide a remarkably versatile platform for achieving desired nanostructures by self-assembly, with lengthscales varying from a few nanometers up to several hundred nanometers. Ionic liquids are an emerging class of solvents with an appealing set of physical attributes. These include negligible vapor pressure, high chemical and thermal stability, tunable solvation properties, high ionic conductivity, and wide electrochemical windows. For various applications it will be necessary to solidify the ionic liquid into particular spatial arrangements, such as membranes or gels, or to partition the ionic liquid in coexisting phases, such as microemulsions and micelles. We have initiated a systematic exploration of ways to achieve this by block copolymer self-assembly. In so doing, a number of fascinating physical phenomena have emerged, which will be highlighted. Examples include the “micelle shuttle”, whereby intact micelles transfer reversibly between an aqueous phase and an ionic liquid as a function of temperature, and doubly responsive micelles, which undergo demicellization and inverse micellization upon heating. Thermoreversible gelation of triblock copolymers provides a simple route to “ion gels” with tunable modulus and ionic conductivity. Applications of these gels in plastic electronics and membranes will also be described.

Speaker's Biography

Tim Lodge graduated from Harvard in 1975 with a B.A. cum laude in Applied Mathematics. He completed his PhD in Chemistry at the University of Wisconsin in 1980, and then spent 20 months as a National Research Council Postdoctoral Fellow at NIST. Since 1982 he has been on the Chemistry faculty at Minnesota, and in 1995 he also became a Professor of Chemical Engineering & Materials Science. In 2013 he was named a Regents Professor, the University’s highest academic rank.
In 1994 he was named a Fellow of the American Physical Society (APS). He received the Arthur K. Doolittle Award from the PMSE Division of the ACS in 1998, and in 2004 he received the APS Polymer Physics Prize. He was elected to Fellowship in the American Association for the Advancement of Science in 2009, and he received the International Scientist Award from the Society of Polymer Science, Japan. He was the recipient of the 2010 Prize in Polymer Chemistry from the ACS, and was also elected a Fellow by the ACS in 2010. In 2012 he received the Minnesota Award from the Minnesota Section of the ACS, and the Postbaccalaureate, Graduate and Professional Education Award from the University of Minnesota. Since 2001 he has been the Editor of the ACS journal Macromolecules. In 2011 he became the founding Editor for ACS Macro Letters. He has served as Chair of the Division of Polymer Physics, APS (1997–8), and as Chair of the Gordon Research Conferences on Colloidal, Macromolecular and Polyelectrolyte Solutions (1998) and Polymer Physics (2000). Since 2005 he has been Director of the NSF-supported Materials Research Science & Engineering Center at Minnesota. He has authored or co-authored over 330 papers in the field of polymer science, and advised or co-advised over 50 PhD students. His research interests center on the structure and dynamics of polymer liquids, including solutions, melts, blends, and block copolymers, with particular emphases on self-assembling systems using rheological, scattering and microscopy techniques.

Refreshments

Refreshments are available in the I.K. MacKenzie Interaction Room, MacN 217, prior to the colloquium