3.1. Comb Polymer

In our model system, a comb polymer is composed of many evenly distributed linear arms and a linear backbone in which each monomer is linked by one end of an arm (see Figure 13a). The monomer number of the backbone and each arm are Lb and La, respectively. The arm number of the polymer is Na. Correspondingly, the total monomer number is N=Lb+NaLa. Specifically, the monomers of the backbone and arms having excluded-volume short-range interactions between non-bonded beads are taken into account by the Lennard–Jones (LJ) potential

where r=|ri−rj| denotes the distance between the centers of two monomers i and j located at ri and rj. σ and ε are taken as unit length and energy, respectively.

(a) Schematic of the LCB comb polymer with backbone length Lb and arm length La. (b) The profile of shear flow in xoz view.

The bond that connects adjective monomers is described by a finitely extensible nonlinear elastic (FENE) potential [57]

where r denotes the distance between the centers of two monomers connected by the bond, l0 is the maximum bond length and K is the spring constant. l0=1.5σ is chosen to avoid bond crossing [58] and the spring constant is chosen to be K=30ε/σ2.