Uniaxial deformation of bridging polymer systems: A Monte Carlo study

Abstract

A new approach for the equilibrium deformation of three-dimensional chains, that are bigrafted to parallel planes is presented. The underlying lattice Monte Carlo algorithm is the bond fluctuation model. In addition to the excluded-volume interaction of this a priori athermal algorithm, we incorporated external potentials in order to enable direct detection of forces. The whole deformation process is split up into a series of separate steps. Each step consists of a generation process and subsequent relaxation procedures. Stress and strain are simultaneously calculated as time-averaged quantities of sufficiently equilibrated systems. Stress–strain relations ranging from compression to the highly stretched regime were simulated by variation of both chain length, N, and grafting density, σ. In the high-density limit the simulation data agree perfectly with a simple one-dimensional theory. The N and σ dependency of the distance, h0(N,σ), of grafting planes at vanishing force is in qualitative agreement with theoretical predictions for an intermediate regime of σ. The simulated force–length relations are in satisfactory agreement with current scaling predictions.

The bridging force between two plates by polyelectrolyte chains

“…The bridging was extensively studied experimentally [6][7][8], theoretically [9][10][11] and by Monte Carlo simulations [12][13][14][15][16]. It was exploited practically for water purification by adding high molecular weight polyacrylamides to flocculate the small particles suspended in water [17].…”

Bridging of an Isolated Polymer Chain

“…Models of bridging in a variety of multichain systems have used mean-field, − scaling, ,− ,, and Monte Carlo − methods. Evidence for the attractive forces caused by bridging has been obtained by measuring directly the forces between two surfaces using the surface force apparatus (SFA) , and atomic force microscopy (AFM) and indirectly from neutron diffraction experiments on suspensions. , In the measurements reported recently by Swenson et al, , the effect of adding poly(ethylene oxide) (PEO) to an aqueous/clay suspension is analyzed.…”

Monte Carlo Studies on the Deformation Behavior of Entangled Polymer Chains

“…In the first one (Type I), Figure 1, the entanglements (loops) follow the deformation axis, and in the second one (Type II), Figure 2, they are orientated perpendicular to the deformation axis. For both systems we used the method of confined self-avoiding walks (CSAWs), [1] in which all chains and monomers are located between the two surfaces F 1 and F 2 . This is done in order to prevent disentanglement of the loops.…”

“…Thus, they give rise to a retracting force in the strongly stretched state. [1] Chains bridging the amourphous phase between crystalline lamellae, so-called "tiechains", are supposed to have significant influence on the stability of partially crystalline polymers.…”