[SY-H7] Tracing the interplay of polymer topology and hydrodynamics
Polymers exhibit a variety of topologies ranging from linear to cyclic and various knot types, which are
of importance in biology, rheology and material science. Macromolecules of distinct topology consist of the
same type and number of monomers making it challenging to separate them using chemical approaches.
Nevertheless, topology influences strongly their response to flow fields in concentrated [1] and dilute
solutions [2]. Exploiting these differences for future separation strategies requires a detailed understanding
of the interplay of hydrodynamic interactions and topology. Due to the inherent separation of time scales
of macromolecules and solvent, here the Multi-Particle Collision Dynamics algorithm is employed to
couple an explicit coarse-grained solvent to polymers treated with Molecular Dynamics.
We investigated the transport of topologically-distinct polymers in microfluidic slit channels. We find
that in bare channels and in dilute solutions there is only minor difference in the migration behavior,
which is not sufficient for separation. In contrast, decorating the channel walls with attractive spots
arranged on a track parallel to the flow results in a reliable and novel strategy for separation of linear and
ring polymers that takes full advantage of the different topologies [3]. Those spots effectively capture and
immobilize linear chains, while forcing ring polymers to change their preferred orientation close to the
walls. In doing so, ring polymers are enabled to roll along the spots with a finite velocity. Furthermore,
investigation of the migration in semi-dilute linear and ring polymer mixtures exhibits an astonishing
difference. Finally, we extend our studies to knotted polymers to construct knot-sensitive filters.
References
[1] Kapnistos, M.; Lang, M.; Vlassopoulos, D.; Pyckhout-Hintzen, W.; Richter, D.; Cho, D.; Chang, T.;
Rubinstein, M. Nat. Mater. 2008, 7, 997-1002.
[2] Hsiao, K.-W. W.; Schroeder, C. M.; Sing, C. E. Macromolecules 2016, 49, 1961-1971.
[3] Weiss, L. B.; Nikoubashman, A.; Likos, C. N. ACS Macro Letters 2017, 6, 1426-1431.
of importance in biology, rheology and material science. Macromolecules of distinct topology consist of the
same type and number of monomers making it challenging to separate them using chemical approaches.
Nevertheless, topology influences strongly their response to flow fields in concentrated [1] and dilute
solutions [2]. Exploiting these differences for future separation strategies requires a detailed understanding
of the interplay of hydrodynamic interactions and topology. Due to the inherent separation of time scales
of macromolecules and solvent, here the Multi-Particle Collision Dynamics algorithm is employed to
couple an explicit coarse-grained solvent to polymers treated with Molecular Dynamics.
We investigated the transport of topologically-distinct polymers in microfluidic slit channels. We find
that in bare channels and in dilute solutions there is only minor difference in the migration behavior,
which is not sufficient for separation. In contrast, decorating the channel walls with attractive spots
arranged on a track parallel to the flow results in a reliable and novel strategy for separation of linear and
ring polymers that takes full advantage of the different topologies [3]. Those spots effectively capture and
immobilize linear chains, while forcing ring polymers to change their preferred orientation close to the
walls. In doing so, ring polymers are enabled to roll along the spots with a finite velocity. Furthermore,
investigation of the migration in semi-dilute linear and ring polymer mixtures exhibits an astonishing
difference. Finally, we extend our studies to knotted polymers to construct knot-sensitive filters.
References
[1] Kapnistos, M.; Lang, M.; Vlassopoulos, D.; Pyckhout-Hintzen, W.; Richter, D.; Cho, D.; Chang, T.;
Rubinstein, M. Nat. Mater. 2008, 7, 997-1002.
[2] Hsiao, K.-W. W.; Schroeder, C. M.; Sing, C. E. Macromolecules 2016, 49, 1961-1971.
[3] Weiss, L. B.; Nikoubashman, A.; Likos, C. N. ACS Macro Letters 2017, 6, 1426-1431.