BROWNIAN DYNAMICS SIMULATION OF GELATION IN SOFT-SPHERE SYSTEMS WITH IRREVERSIBLE BOND FORMATION

Brownian dynamics simulation is used to study the structure and small- deformation shear rheology of three-dimensional particle gels formed f rom a model of soft spherical particles incorporating a combination of flexible, irreversible bond formation and non-bonded interparticle in teractions. An essential feature of the model is the restriction of an gular reorganization of cross-linked aggregates during and after gelat ion. Numerical data relating to the fractal structure and porosity of the gels are compared with those from some related particle gel simula tion models in two and three dimensions. Stress relaxation and frequen cy dependent rheological properties are determined as a function of th e strength and nature of the interparticle interactions, and the resul ts are discussed in relation to structural properties. A linear relati onship is demonstrated between the high-frequency modulus and the numb er of bonds in the gel network.