| 초록 |
Micelles in solution are subjected to shear flow during processing and thus it is of great importance to understand how shear flow affects the formation of micelles. In the present work, Brownian dynamics simulation is carried out to study the effect of shear flow in micellization behavior of B2A4 diblock copolymers (B and A represents hydrophobic and hydrophilic segment, respectively). Prior to applying shear flow, the cmt of the solution in the absence of shear is determined to identify three regimes of unimer state, transition state from unimer to micelles, and micellar state. Shear flow is then applied at each of three regimes and various static and dynamic properties of micelles are measured as a function of shear rate. The simulation results show that at low shear rates, micellar distribution is slightly shifted to low aggregation number. As shear rate increases, the mean aggregation number of a micelle becomes smaller and eventually, the micelles break up at shear rates higher than a critical rate comparable to inverse time scale of segmental relaxation of chain. Rheological properties such as shear stress are calculated and the results in connection with micellar properties are discussed. |
