The effect of polymer chain length on the mechanical properties of triblock copolymer gels

An ABA triblock copolymer in a midblock selective solvent is studied as a function of the chain length, using a novel dissipative particle dynamics (DPD) model which includes a modified segmental repulsive potential (mSRP) that restricts chain crossing. Deformation under uniaxial tension using the DPD method, with and without the mSRP, was used to extract the cross-link and entanglement portions of the modulus. The results exhibit the expected theoretical scaling with chain length for lower strain rates. Structural properties, such as bridge fraction and the extent of entanglements in the polymer matrix, were also quantified.