Abstract - Laibinis - 9413894 Microwave-based heating of chemical systems holds the promise of increased energy efficiency and superior temperature control over chemical processes. Particular advantages of microwave heating appear to be the abilities to increase reaction rates (by seemingly superheating the reaction medium) and to heat systems uniformly (by applying heat from within a vessel rather than by conduction from its walls). In this work, surfactants will be used to structure fluids as a means for enhancing the desirable chemical processing features of microwave-based heating. The abilities to control and structure the polarity of a liquid phase through the formation of micellar domains are expected to yield new methods for tailoring and optimizing the heating liquid phases by incident microwaves. The methods will produce environmental and processing benefits by reducing energy consumption in the heating of chemical streams and by producing uniform heating profiles within reaction vessels. This latter ability will avoid exposing reaction mixtures to the elevated and spatially variant temperatures that typically reduce reaction specificity and lead to enhanced material decomposition and waste products. It is the goal of this work to develop new processing methods for controlling the heating of chemical systems by microwaves, in particular, for non-polar chemical phases where the use of microwave radiation for heating has been ineffective. The strategy uses the abilities of self-assembled polymer and surfactant systems -- micelles, reverse micelles, vesicles, liposomes, etc. -- to produce specific isolated micro-domains of different polarities within a liquid continuum. The resulting polar and non-polar domains represent specific regions within the liquid that will absorb the incident microwave radiation differently, with the polar regions being responsible for efficient energy absorption and subsequent rapid thermal dissipation to the contacting non-polar phase. In these self-assembled systems, the dielectric properties, contents, sizes, and relative amounts of the individual domains can each be readily changed, and their manipulation should provide a controlled method for modifying the microwave absorbing characteristics of a liquid phase. Aqueous dispersions should allow for the efficient absorption of the incident microwave radiation and the use of frequencies (2.45 GHz) and hardware presently dedicated for microwave heating. From an industrial standpoint, an important aspect of the work is that the energy absorbing properties of reaction/solvent systems will be varied by straightforward chemical means and will not require changes to the microwave hardware.
