Robert W. Cohn (University of Louisville)

Professor of Electrical and Computer Engineering 

and Director of the ElectroOptics Institute and Nanotechnology Center at the

Fluid mechanical forces can be used to naturally induce polymeric
liquids to self-assemble into suspended fibers, membranes and
air-bridges that have nanoscale features and aspect ratios exceeding
10,000:1. The fabrication process is quite robust, enabling defect-free
arrays of identical structures to be produced with even crude hand
application. Nanofiber air-bridges have been produced in seconds with
numerous types of organic polymers, nanomaterial-polymer composites, and
biopolymers—including with fibrin and DNA.

Most recently we have assembled an ultraflexible air-bridge in the form
of a micron-scale bead on a 50 to 200 nanometer diameter string. The
relatively large bead enables both simple observation and
nanomanipulation of the structure under a light microscope. Force
detection limits of under a piconewton are estimated, making visual
sensing under a light microscope a possible alternative to traditional
atomic force microscopy and laser trapping for detection of biomolecular
forces. This talk will present the self-assembly method, measurements of
resulting magneto-mechanical properties of the beaded fibers, and new
ideas for using the magnetic nanorods to further control and modify the
process of self-assembly.