(288h) Design and Testing of a Microfluidic Four-Roll Mill Device Conference: AIChE Annual MeetingYear: 2006Proceeding: 2006 AIChE Annual MeetingGroup: Engineering Sciences and FundamentalsSession: Microfluidics and Small-Scale Flows I Time: Tuesday, November 14, 2006 - 5:00pm-5:15pm Authors: Lee, J. S., LG Chem Research Park Dylla-Spears, R., University of California at Berkeley Teclemariam, N. P., University of California at Berkeley Muller, S. J., University of California at Berkeley The four-roll mill device invented by G.I. Taylor  has been valuably used to generate mixed flows that can be varied from purely extensional to shear to purely rotational. However, it is extremely difficult to realize the four-roll mill concept in a microdevice by changing only the flow rate. Hudson and co-workers  suggested a novel design for a micro four-roll mill device, but could not reach purely rotational flow in a device. In this presentation, we suggest another design for the micro four-roll mill that can cover the entire spectrum of flow types including purely rotational flow. Numerical simulations using a pseudo 3-D model confirmed the potential of the design, which was verified by experiments using PDMS and silicon devices. Application of this four roll mill device to examining drop deformation in the microchannel or to enhancing mixing efficiency by sinusoidal change of the inlet flow rate will also be discussed. 1. Taylor, G.I., 1934. The formation of emulsions in definable fields of flow. Proc. Royal Soc. London A 146: 501-523. 2. Hudson, S.D., F.R. Phelan, Jr., M.D. Handler, J.T. Cabral, K.B. Migler, and E.J. Amis, 2004. Microfluidic analog of the four-roll mill. Appl. Phys. Lett. 85: 335-337.