Single molecule rod-globule phase transition for brush molecules at a flatinterface

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