The structure of an end-grafted polymer layer immersed in poor solvent
is investigated through Monte Carlo simulation based on Edward's Hami
ltonian. When the solvent quality becomes sufficiently poor, lateral i
nhomogeneities are observed to develop in the monomer density in the d
irection parallel to the grafting plane. A micro-phase-separated confo
rmation is observed at long times. The length scale characteristic of
the micro-phase structure is found to be consistent with a two-dimensi
onal random walk. The simulation gives results consistent with the sta
bility line predicted by Yeung, Balazs and Jasnow (Macromolecules, 26
(1993) 1914).