Molecular sensor of elastic stress in a random flow

Department of Physics of Complex Systems, Weizmann Institute of Science - Rehovot 76100, Israel

Received: 27 January 2010
Accepted: 4 May 2010

Abstract

A single fluorescently stained T4DNA molecule with known elastic properties is used as a stress sensor in a random flow. Using measured polymer stretching statistics and its known elastic properties, the elastic stress in elastic turbulence, created by the same unlabeled molecules, is directly obtained for the first time as a function of rotation speed and T4DNA concentration in water-saccharose solvents. It is found that i) the value of elastic stress is by at least two orders of magnitude larger than theoretically predicted that disproves the existing theory of elastic turbulence, and ii) the normalized elastic stress in the elastic-turbulence regime linearly depends on the local Weissenberg number, which defines the polymer stretching, for all used polymer concentrations and saturates at its highest values.