Single molecule studies of flexible polymer systems

Fluorescence microscopy;polymers;single molecule dynamics

Brockman, Christopher A.

关键词: Fluorescence microscopy;    polymers;    single molecule dynamics;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/49461/Christopher_Brockman.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Polymeric materials play a profound role in our daily lives. There have been many keyadvances in polymer processing over the last several decades, but much of the underlyingmolecular behavior and physics of polymer solutions is not fully understood. Single moleculestudies of polymer solutions provide an avenue for studying polymer dynamics and can aid indeveloping new molecular models of dynamic behavior. For nearly two decades, fluorescentlylabeleddouble stranded DNA (dsDNA) has been the model system for studying single moleculepolymer dynamics in non-equilibrium conditions; however, dsDNA is a semiflexible polymerwith markedly different local molecular properties compared to flexible polymer chains, such assynthetic organic polymers.This thesis presents a new methodology for studying truly flexible polymers at the singlemolecule level. We have demonstrated the ability to synthesize long strands of fluorescentlylabeledssDNA, and we directly imaged single ssDNA polymers stretching in fluid flows inmicrofluidic devices (Chapter 2). In addition, we have developed an automated flow-basedmethod to isolate individual polymer chains for long periods of time in planar extensional flow(Chapter 3). By combining the tools we developed we were able to study the longest polymerrelaxation time dynamics of flexible polymers (Chapter 4), and utilizing both Browniandynamics simulations and single molecule experiments, we were able to study the relaxationdynamics of flexible chains. In addition, we were able to use to automated hydrodynamic trap tostudy dynamics of polymers in precisely controlled flow conditions that have not been studiedpreviously (Chapter 6), as well as the dynamics of a different class of materials: ring polymers.