We have carried out extensive molecular-dynamics simulations of randomly cross-linked polymers and studied the onset of rigidity as the number of cross-links is increased. We find that for our systems, consisting of chains of length N=10, 20, 30, and 50, the shear modulus E vanishes at a concentration of cross-links that is well above the geometric percolation threshold and that it seems to approach zero as E~(n-nc)f, where the exponent f is considerably smaller than either the classical value f=3 or the corresponding exponent t~=2.0 of the conductivity of random resistor networks.
關聯:
Physical Review E (Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics) 54(5), pp.5370-5376
