436635 Microscale Yielding in Colloidal Rod Gels of Bacterial Cellulose Nanofibers

Monday, November 9, 2015
Ballroom F (Salt Palace Convention Center)
Patrick T. Spicer, Chemical Engineering, University of New South Wales, Sydney, Australia, Jie Song, Chemical Engineering, UNSW Australia, Sydney, Australia and Todd M. Squires, UCSB Chemical Engineering, University of California, Santa Barbara, Santa Barbara, CA

High aspect ratio colloids can form elastic structures at amazingly low volume fractions, and there is an expectation that rod systems could be much more efficient than gels made from spherical colloids. However, the lowest measured gel volume fractions for rods and spheres tend to be of similar magnitude. We examine the theoretical expectation of percolation structures for rods and spheres and compare against active microrheological measurements of a bacterial cellulose network in water.  The mechanism and rate of yielding by the fiber network is shown to vary in a way consistent with a two-fluid model and our measurements are used to build on previous observations of higher suspension efficiency for sparse gels than for dense colloidal glasses.

Extended Abstract: File Not Uploaded
See more of this Session: Poster Session: Fluid Mechanics (Area 1J)
See more of this Group/Topical: Engineering Sciences and Fundamentals