Constant perimeter trough

Figure 3.1. Constant perimeter Langmuir-Blodgett trough. The pulleys round which the PTFE coated tape passes are mounted on carriages which move so that the perimeter of the enclosed area remains constant but the area enclosed by the tape varies.

Figure 12.11 A typical Langmuir trough for the fabrication of LB films showing the surface pressure monitor (P), the wettable plate (W), the substrate (S) attached to the deposition mechanism (D) via the clamp (C), the moveable constant perimeter barriers (MB), the barrier drive motors (BD) and the water bath (B).

Arachidic acid LB fdms were built-up at a surface pressure of 32 mN m using a constant perimeter barrier trough located in a microelectronics clean room. The subphase used was ultrapure water purified by reverse osmosis, carbon filtration, two stages of deionisation and UV sterilisation at a temperature of 20 1 C and pH 5.8 0.2. Y-type deposition was noted with an average transfer ratio of 0.9 (upstrokes and downstrokes). 

Figure 3.3 A typical constant perimeter Langmuir trough designed for the deposition of single materials. 

Figure 3.5 (a) An example of a constant perimeter alternate-layer Langmuir trough showing fixed central barrier (FB) and the motor-driven rotary mechanism (R). Also shown are the barrier ribbon (B), the barrier drive motors (BD) which are attached to the movable barriers (MB), the surfece pressure monitors (W and II), and the substrate (S). (b) Also shown is the alternate layer molecular architecture realizable using the alternate layer technique. 

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