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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 20: Polymer and Molecular Dynamics, Friction and Rheology

CPP 20.7: Vortrag

Dienstag, 28. März 2023, 11:30–11:45, ZEU 255

A nanofluidic system based on cylindrical polymer brushes: molecular dynamics simulation and scaling theory — •Cheng-Wu Li — Leibniz-Institut für Polymerforschung Dresden, Germany

Using molecular dynamics simulations and scaling theory, we present a systematic study of the function of cylindrical nanopores which are decorated with polymer brushes. Our focus is on the regimes in which these systems are able to function as controllable (switchable) gates for bulky nanoparticles. In a slightly poorer solvent, closed cylindrical brushes facilitate the self-organised formation of droplets from a continuous flow of incoming nanoparticles We analyze droplet formation and propagation by means of simple scaling arguments which are tested in the simulations. Polymer brushes in marginally poor solvents serve as a pressure feedback system, exhibit a collapse transition under the moderate pressure of the incident flow, without the need for additional external stimuli, and finally close spontaneously after droplet passage. Our results qualitatively demonstrate the control of polymer brushes over continuous fluids and droplet formation, and its effectiveness as a means of fluid control can be used to design nanofluidic rectification devices that operate reliably under moderate pressure.