Tube Diameter of Stretched and Compressed Permanently Entangled Polymers

Abstract

Entangled ring polymers behave like gels. By applying uniaxial compression and stretching to such gels initially equilibrated with molecular rebridging Monte Carlo moves, and using isoconfigurational ensemble simulations to explore the tube confinement, we studied the strain dependence of the tube contour and tube diameter. It is found that the tube contour length increases with both compression and stretching, the tube diameter increases with strain monotonically, and the strain dependences of both tube contour length and tube segment orientation are well described by the independent alignment approximation (IAA). For strains ranging between 0.5 and 2.0, fractional changes of the tube contour length and the tube diameter are less than 10%. The orientation dependence of the tube diameter is also analyzed and found to be weak. These results should prove useful for constructing theories of gel elasticity.