ZB 10 - Soft Condensed Matter (R. Holyst)

Activation Energy for Mobility of Dyes and Proteins in Polymer Solutions: From Diffusion of Single Particles to Macroscale Flow

Author(s): Sozanski, Krzysztof and Wisniewska, Agnieszka and Kalwarczyk, Tomasz and Holyst, Robert
Title: Activation Energy for Mobility of Dyes and Proteins in Polymer Solutions: From Diffusion of Single Particles to Macroscale Flow
Abstract: We measure the activation energy Ea for the diffusion of molecular (dyes and proteins of radii from 0.52 to 6.9 nm) and for flow in a model complex liquid-aqueous solutions of glycol. We cover a broad range of polymer molecular concentrations, and temperatures. Fluorescence correlation and rheometry experiments reveal a relationship between the of the activation energy in polymer solutions over the one in solvent Delta E-a and simple parameters describing the structure of system: probe radius, polymer hydrodynamic radius, and correlation Delta E-a varies by more than an order of magnitude in the systems (in the range of ca. 1-15 kJ/mol) and for probes larger than the polymer hydrodynamic radius approaches the measured for macroscopic flow. We develop an explicit formula the smooth transition of Delta Ea from the diffusion of probes to macroscopic flow. This formula is a reference for quantitative analysis of specific interactions of moving with their environment as well as active transport. For the power developed by a molecular motor moving at constant velocity u is proportional to u(2) exp(E-a/RT).
Journal: PHYSICAL REVIEW LETTERS
Volume: 111
ID: ISI:000327388700014
Year: 2013
DOI: 10.1103/PhysRevLett.111.228301