Sliding dynamics of multi-rings on a semiflexible polymer in poly[n]catenanes

Abstract

The sliding dynamics of one- or multi-ring stuctures along a semiflexible cyclic polymer in radial poly[n]catenanes is investigated using molecular dynamics simulations.

Sliding Dynamics of Ring Chains on Two Asymmetric/Symmetric Chains in a Simple Slide-Ring Gel

“…The chain stiffness is introduced by means of a bending potential between two adjacent bonds [ 13 , 17 ]. where θ is the angle between two consecutive bonds, and K bending is the bending constant, which represents the bending energy.…”

“… where θ is the angle between two consecutive bonds, and K bending is the bending constant, which represents the bending energy. Here the θ 0 is fixed to be θ 0 = π[(N ring − 2)/N ring ] for ring chains, and θ 0 = π for the two axial chains and the linking chain [ 13 , 14 , 15 , 16 , 17 , 30 , 31 ]. The bending energy K bending is chosen to be 100 K B T/rad 2 for ring chains.…”

“…The timestepτ is chosen to be τ = 0.005τ 0 , and the constant temperature is fixed as T 0 = 1.0 in the unit ofε/k B controlled by the Langevinthermostat. The motion of all monomers is described by means of the following Langevin equation [ 13 , 17 , 18 , 33 ]. where r i is the coordinate of the i-th monomer, and the friction constant is set as γ = 0.5τ 0 −1 .…”

“…Wang et al successfully reported the dynamics of the ring chain threaded on the axial chain through a mesoscopic simulation method and found that the hydrodynamic interactions significantly enhance the diffusion and relaxation of the threading ring chains [ 16 ]. We also investigated the sliding dynamics of multi-rings on a semiflexible chain in catenanes using molecular dynamics simulation and explored the influences of the bending energy of axial polymer chain and the number of threading ring chains on the sliding process of ring chains [ 17 ]. We performed further investigations to study the sliding dynamics of ring chains on a knotted polymer chain in rotaxane and found that the sliding behavior of the ring chain exhibits a sub-diffusion at the intermediate time range resulting from the intra-strand interaction between the ring chain and the knotted axial chain in the knot crossing region [ 18 ].…”

“…The sliding dynamics of ring chains in mechanically interlocked polymers is crucial for understanding the origin of both the softness and toughness of SR gels. Some previous simulation works haveonly concentrated on the sliding dynamics of isolated ring chains along the axial chain in which two ring chains arenot linked by a polymer chain [ 12 , 13 , 14 , 15 , 16 , 17 , 18 ]. In fact, two ring chains are always linked by a polymer chain in SR gels [ 19 , 20 , 21 , 22 , 23 ], and the sliding dynamics of one ring chain is closely related tothe sliding motion of another linked ring chain.…”