Langmuir-Blodgett films surface forces

J.A. DeRose, R.M. Leblanc, Scanning Tunneling and Atomic Force Microscopy Studies of Langmuir-Blodgett Films, Surface Sci. Reports 22 (1995) 73. (Review concerning STM and AFM studies of LB films, covering 1987-1994.)... 

An example, Figure 9 is an SFM image of a Langmuir-Blodgett film. This film was polymerized with ultraviolet light, giving a periodicity of 200 A, which is seen in the associated Fourier transform. The low forces exerted by the SFM tip are essential for imaging such soft polymer surfaces. 

Extremely low interaction forces in monomolecular adsorption layers on liquids, Langmuir Blodgett films or in solid interfaces are the precondition for low energy surfaces. Perfluorocarbons or terminal fluorinated parts in amphiphilic molecules and fluoropolymers meet these demands. 

After creation of the compressed film, it can be transferred to an electrode surface. The characteristics of the substrate can tremendously affect the quality of the resulting Langmuir-Blodgett film (20), and dictate how the initial layer is transferred. Figure 8.4 depicts a common film transfer method, where a hydrophilic substrate is vertically lifted through a Langmuir film. The attractive forces between the surface and the head groups result in transfer of the layer, such that the film physisorbs on the electrode surface. These... 

Local Piezoelectric Response and Surface Potential of Dielectric AND Ferroelectric Langmuir-Blodgett Films Studied by Electrostatic Force Microscopy... 

The tip of an atomic force microscope makes a single point contact with a surface. Consequently, understanding tribological behavior becomes intellectually simpler. Friction has been shown to be correlated not with the magnitude of the adhesion between two bodies, but rather with the adhesion hysteresis [6]. Our recent study of a model system, a Langmuir-Blodgett film on mica [7], shows no dependence on adhesion hysteresis, but rather a dependence on molecular orientation [2]. 

Holmberg M ef al 1997 Surface force studies of Langmuir-Blodgett cellulose films J. Colloid Interface Sci. 186 369-81... 

An ordered antibody array has also been assembled on the solid surface by a combination of Langmuir Blodgett (LB) film method and self-assembling method. An ordered monolayer of protein A is deposited on the solid surface by LB method, which is followed by self-assembling of antibody. Individual antigen molecules which are complexed with the antibody array have been quantitated selectively by atomic force microscopy (AFM). 

In atomic force microscopy (AFM) solid surfaces (this includes also molecular mono- and multilayers on solid supports in the form of Langmuir-Blodgett (or LB) films) are scanned at constant van der Waals forces in the region of 10 9-10 7 N of force. This is done point by point and line by line. A computer processes the images which consist of the data points. 

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