A new dipping and raising device for Langmuir film deposition

Abstract

The main part of the apparatus for Langmuir film deposition is its dipping and raising device which can affect the quality of films. A new mechanism, attractively simple in both its operational principle and construction, is described for up and down strokes of the slide across the monolayer-covered surface. The slide attached to the cylinder of an inverted, conventional glass syringe (clinical) moves downwards due to the hydrostatic pressure of water and moves up when the latter is sucked out. The key points of the mechanism are the use of an incompressible liquid instead of compressible gas, negligible frictional variations and hence uniformity of the driving force, and speed control as low as 0.1 mm s^-1 or better. In addition, it does not involve the design and precise fabrication of either a PTFE guide tube or the piston, as described in an earlier method. A demountable PTFE trough and some experimental results on Langmuir films obtained using the equipment are also discussed.