Direct observation of the behavior of single macromolecules at the gas-liquid interface

The isolation of single macromolecules in their native state is achieved via a matrix embedding method, i.e., co-spreading a relevant dilute solution onto the water surface in a trough. These macromolecules in the transferred monofilms are visualized by high-resolution transmission electron microscopy. The individualized semiconducting tetra(methoxy)-tetra(octoxy)-phthalocyaninatopoly(siloxane) (PcPS) molecules serve as model molecular wires. Their contour, interaction and properties are evaluated in terms of the elastic theory for rigid rods based on electron micrographs. Single polystyrene molecules are conformationally confined in two dimensions (2D) by shape-persistent polymers; this kind of 2D solid solution challenges existing theories on thermodynamics of flexible and rigid molecules. (C) 1998 Elsevier Science S.A. All rights reserved.