Abstract: A barrier mechanism for isolating a drive chain from an active chamber in a Langmuir trough is provided. The chain drives a substrate mounted on a backing plate through the active chamber in order to coat the substrate. The chain passes through a "C" shaped barrier adjacent to the active chamber. The barrier mechanism comprises a resilient strip biased by a leaf spring to seal a side opening in the barrier. A wedge is mounted to the backing plate to open the resilient strip and leaf spring and thereby permit the backing plate to pass through the side opening as the substrate is driven into the active chamber.

Abstract: An apparatus for depositing a mono or multimolecular layer film on a substrate has a trough (1) in which the liquid sub-phase (W) is received, the sub-phase carrying a monomolecular layer film of e.g. a diacetylenic fatty acid. The apparatus has a barrier system (4) consisting of a boom (40) which is pivotted on the center of a rigid spoked ring (42) and pivotable towards and away from the adjacent spoke to compress the molecular layer the desired amount. The vertical position of the ring is adjustable by bolts (24) to position the upper surface of the adjacent spoke (41) and lower surface of the boom (40) below but not through the liquid surface. This enables the monomolecular layer to be compressed without leakage of molecules and also allows contaminants to be collected by sweeping the boom across the surface before the layer is added.