LB Membranes for the Alignment Layer

It is well known that surface active agents with hydrophobic groups such as long alkyl chains with hydroxy or carboxy groups form monomolecular films on the surface of water. By removing the formed film onto a substrate, the monomolecular film can exist on the substrate. Monomolecular layers can also be stacked to form multilayers with several molecular layers. The monomolecular film is named a Langmuir-Blodgett film after the names of the inventors, or usually LB film for short. 

To move the monomolecular layers from water surface to substrates, two methods have been investigated. During the process of one method, the substrate is moved up or down perpendicular to the water surface to move the monomolecular film from the water surface to the substrate (method A), as shown in Pig. 3.5.1. In another method, the substrate surface is held parallel to the water surface and touches onto the monomolecular film parallel to the water surface so shifting the film to the substrate (method B). 

Substrate is moved up and down perpendicular to the water surface to move the monomolecular film from the water surface to the substrate (method A). 

there are many categories for method A. In the method shown in Pig. 3.5.1, the LB film is transferred onto the substrate only when the substrate is lifted upwards. During this process, pressure is added to the edge of the monomolecular film on the 

It is well known that liquid crystalline materials align in the extension direction on an extended polymer film surface. The polymer LB film formed by moving the substrates perpendicularly is considered to be a uniaxially extended polymer film, and therefore, liquid crystal alignment on the surface of such a polymer LB film can be expected. 

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