Thermal properties of knotted block copolymer rings with charged monomers subjected to short-range interactions

Taklimi, Neda Abbasi; Ferrari, Franco; Piątek, Marcin Radosław; Tubiana, Luca

doi:10.1103/physreve.108.034503

Cited by 2 publications

(2 citation statements)

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“…Specifically, introducing an explicit representation of counterions (CIs) in solution leads to the emergence of novel phenomena, including enhanced susceptibilities of knot tightening/delocalization to salt valency, 22,23 concentration, 22−24 pH, 22 and solvent-screening power. 22,23 block copolyelectrolytes carrying neutral and charged segments, 23,25,26 where both the statics and dynamics of the knotted region can be tuned in ways not available for uncharged homo-and copolymers, whose behavior is instead mostly informed by the contour length, persistence length, and characteristic knot size. 27−31 In this work, we address one related aspect that has so far remained unexplored, namely, the impact of CI size on the properties of knotted strong (fully charged) PEs.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Recent studies have shown that the complex phenomenology observed in knotted PEs with mean-field (Debye–Hückel-like) screened interactions is enriched when more realistic descriptions are used for the ionic solution. Specifically, introducing an explicit representation of counterions (CIs) in solution leads to the emergence of novel phenomena, including enhanced susceptibilities of knot tightening/delocalization to salt valency, , concentration, − pH, and solvent-screening power. , Further levels of complexity can emerge in block copolyelectrolytes carrying neutral and charged segments, ,, where both the statics and dynamics of the knotted region can be tuned in ways not available for uncharged homo- and copolymers, whose behavior is instead mostly informed by the contour length, persistence length, and characteristic knot size. − …”

Section: Introductionmentioning

confidence: 99%

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Effect of Counterion Size on Knotted Polyelectrolyte Conformations

Tagliabue,

Micheletti,

Mella

2024

J. Phys. Chem. B

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Using Langevin dynamics simulations and a coarse-grained primitive model of electrolytes, we show that the behavior of knotted circular strong polyelectrolytes (PEs) in diluted aqueous solution is largely affected by the diameter of the counterions (CIs), σCI. Indeed, we observe that both gyration radius and knot length vary nonmonotonically with σCI, with both small and bulky CIs favoring knot localization, while medium-sized ones promote delocalized knots. We also show that the conformational change from delocalized to tight knots occurs via the progressive coalescence of the knot’s essential crossings. The emerging conformers correspond to the minima of the free energy landscape profiled as a function of the knot length or PE size. We demonstrate that different conformational states can coexist, the transition between them appearing first-order-like and controlled by the enthalpic and entropic trade-off of the amount of CIs condensed on the PE. Such balance can be further altered by varying CI concentrations, thus providing an additional and more convenient tuning parameter for the system properties. Our results lay the foundation for achieving broader and more precise external adjustability of knotted PE size and shape by choosing the nature of its CIs. Thus, they offer new intriguing possibilities for designing novel PE-based materials that are capable of responding to changes in ionic solution properties.

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