Abstract:
The next generation of telecommunication networks requires electrical conductors that operate at frequencies of tens of gigahertz. In principle, such conductors can be made by braiding thin, conducting fibers. But each fiber must have a diameter approximately equal to the skin depth, which is on the order of 1 micrometer at 10 GHz. Because such small fibers break easily, current industrial machines cannot braid them. We have developed a technique to braid such small fibers using a 3D-printed device (a "capillary machine") that moves up and down in a tank of water. We attach microscale fibers to polymer discs that float at the water-air interface, such that surface tension repels them from the walls of the device. As a result, we can move the polymer floats – and therefore the fibers – by moving the device. I will explain how we use the mathematics of braids to design the machines, and I will show how they can be used to braid and weave micrometer-scale fibers, as well as to manipulate microscopic objects. This research was done in collaboration with Cheng Zeng, Maya Faaborg, Ahmed Sherif, Martin Falk, Rozhin Hajian, Ming Xiao, Kara Hartig, Yohai Bar Sinai, and Michael P. Brenner.
Speaker Bio:
Prof Vinothan Manoharan (Vinny) is the Wagner Family Professor of Chemical Engineering and a Professor of Physics at Harvard. Vinny's work in colloidal assembly and soft matter science has earned him the reputation as being one of the foremost exponents of experimental soft matter research globally. His group has advanced the use of optical methods and microscopy to study colloidal dispersions. Vinny has a PhD in Chemical Engineering from the University of California, Santa Barbara, where he worked with Professor David J. Pine. He did postdoctoral research with Professor John Crocker at the University of Pennsylvania before joining the faculty at Harvard in 2005.