Behavior of confined telechelic chains under shear

Using Monte Carlo simulations, we investigate the rheological behavior of e nd-functionalized chains confined between two surfaces. The linear chains c ontain a reactive group ("sticker") at each end and thus, have a telechelic architecture. We vary the functionality, f, of these stickers from 0 to 3 and calculate the shear stress for different shear rates. For f > 1, the ch ains form a transient network that effectively blocks the stretching of the chains under shear. As a consequence, the shear stress plateaus to a const ant value at high shear rates. These findings are in agreement with recent experimental studies on a comparable system. For f > 1, we also find that t he limiting shear stress decreases with increasing values of f. (C) 2000 Am erican Institute of Physics. [S0021-9606(00)50829-0].