A structural model for equilibrium swollen networks
Abstract
A tensile blob construction for branched structures is used to explain structural sizes larger than the strand length, as observed in neutron scattering data from equilibrium swollen networks. Under this model, equilibrium swollen networks display a base structural size, the "gel tensile blob" size, ξ, that follows the scaling relationship ξ ~ l/(1/2  χ)^{P}, where l is the monomer length, χ is the Flory interaction parameter and P is a power determined by the connectivity of the network and the degree of interpenetration. The gel tensile blobs compose a largescale linear structure, whose length, L, follows the scaling relationship L ~ Q^{1/2}N_{avg}, where 1/N^{2}_{avg} = ((1/fN_{c}^{2}) + (1/4N_{e}^{2})), Q is the equilibrium swelling ratio, N_{c} is the strand length, N_{e} is the entanglement length and f is the functionality of the crosslinks. The variation of the swelling ratio with molecular weight can now be expressed as Q ~ N_{avg}^{3/5}, which reduces to the correct expressions under the limits N_{e} gg N_{c} and N_{c} gg N_{e}.
 Publication:

EPL (Europhysics Letters)
 Pub Date:
 September 2002
 DOI:
 10.1209/epl/i2002001847
 Bibcode:
 2002EL.....59..714S
 Keywords:

 61.41.+e;
 64.75.+g;
 82.70.Gg;
 Polymers elastomers and plastics;
 Solubility segregation and mixing;
 phase separation;
 Gels and sols