Single Molecule Rod−Globule Phase Transition for Brush Molecules at a Flat Interface

The coexistence of two different conformational states in one molecule has been visualized by scanning force microscopy for a rod−globule transition of brush molecules adsorbed on a water surface. The transition, which occurred upon lateral compression of monolayers, was also examined theoretically by scaling analysis that proved its first-order character. The transition becomes less distinct with decreasing length of the side chains and finally vanishes below a certain critical value.