Shear-induced Polymer Assembly: A Molecular Study

Johns Hopkins University, Baltimore MD

Investigators

Abstract

ABSTRACT PI: Yiider Tseng Institution: Johns Hopkins University Proposal Number: 0072278 The control of the molecular weight of macromolecules is important in pharmaceutical applications, biotechnology, and polymer processing. The PIs plan to use DNA molecules with cohesive ends ("sticky ends") as a model system to study the physics of shear-induced polymerization. Using mechanical rheometry, molecular "combing," shear-flow fluorescence microscopy, molecular sequencing, and gel electrophoresis, they plan to uncover and quantify the fundamental mechanism of shear-induced polymer assembly. In particular, they will investigate: 1. the shear-rate dependence of polymer-length distribution, 2. the reversibility of shear-induced polymerization, 3. the influence of ion charge and concentration in solution, and 4. the effects of polymer length and of 5. polymer-end "stickiness" and temperature on shear-induced polymer assembly. They plan to verify that the shear flow, which favors inter-chain interactions via connection of the cohesive ends of the polymers, induces the assembly. These results will be used to study the behavior of associating polymers under shear and may form the basis of an approach to control polymer assembly in recombitant DNA technology and polymer science.