posted on 2010-02-23, 00:00authored byD. T. N. Chen, K. Chen, L. A. Hough, M. F. Islam, A. G. Yodh
We report measurements of gelling rigid rod networks composed of a semidilute dispersion of surfactant-stabilized carbon nanotubes. Microrheology is employed to follow the rheological evolution of the suspension from a semidilute solution of unbonded tubes to a bonded gel network with finite yield stress. The rheological data at various time intervals during gelation is readily collapsed onto a single time-cure superposition master curve. A theoretical model based on the crossing probability of rods confined to finite volumes is developed to account for network elasticity. Model predictions compare well with computer simulation and experiments as a function of nanotube volume fraction and cure time.