| 초록 |
Upon aging, a freshly collapsed long chain evolves from a crumpled state to a self-entangled globule. This equilibrium globule can be thought of as a large knot. Swelling of such an equilibrium globule in good solvent is a complex two-step process: (i) fast swelling into an arrested stretched structure with conserved entanglement topology is followed by (ii) slow disentanglement that eventually leads to an expanded coil. We discuss the scaling structure of the correlated regions, or``stretched entanglement cells,'' inside the swollen globule. Using computer simulation, we found both mass-mass and entanglement-entanglement power law correlations. The mass-mass correlations are characterized by a set of two exponents, found to be in agreement with a simple Flory-type argument. One of them is consistent with an exponent found in swelling of cross-linked melts Entanglement-entanglement correlations are also characterized by two exponents, both of them slightly larger (by ~0.3) than the related mass-mass exponents. We suggest an interpretation of this difference as evidence of repulsive interactions of about E=-0.3 ln(r) kT between entanglements sliding along the polymer chain. |
