Langmuir-Blodgett films amphiphilic molecules

Fig. 2.22 The preparation of Langmuir-Blodgett films. Amphiphilic molecules, i.e. molecules with a water-soluble and an insoluble end, dissolve in a two-dimensional mode on a water surface (so called spreading). They can be compressed into...

Nakamura T, Tachibana H, Yumara M, Matsumoto M and Tagaki W 1993 Structure and physical properties of Langmuir-Blodgett films of Cgg with amphiphilic matrix molecules Synth. Met. 55 3131-6... 

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. 

Figure 4.1. Schematic diagram of the formation of a Langmuir-Blodgett film. Each amphiphilic molecule is represented by a circle with a tail, where the circle denotes the hydrophilic end of the molecule. The left hand diagram represents the deposition of a monolayer on a hydrophilic substrate moving upwards. The right hand diagram represents the deposition of a second layer during the downward movement of the substrate.

Amino-5-nitropyrimidine, cocrystallization, 455 Amorphous polymers, criteria for use in second harmonic generation, 250-251 Amphiphilic molecules polar Z-type Langmuir-Blodgett films, formation, 473-479 structures, transfer behavior, and contact angles, 474,476-477r Anharmonic oscillator models, nonlinear optical effect-microstructure relationship, 361... 

For organized lamellar structures, like monolayers, Langmuir-Blodgett films and bulk lamellar phases of amphiphiles, the orientation distribution of the molecules is usually described using an axially symmetric orientation distribution function, N(0, with 0 the azimuthal tilt angle. This distribution... 

The structure of these amphiphiles is radically different from that of conventional Langmuir film-forming amphiphiles, where segregation of the hydrophobic and hydrophilic parts of molecules at the air/water interface is a prerequisite. This is the first example of a Langmuir-Blodgett film that is fabricated with a micellelike substance. It is intriguing that amphiphilicity is still required to form a stable monolayer film of hyperbranched polymers, in spite of their fundamental structural differences from conventional amphiphiles. 

Figure 6.13 Deposition of a Langmuir-Blodgett film. Step 1, the amphiphilic molecules are spread on the air-water interface. Step 2, the molecules are compressed by movable barriers to form a close-packed monolayer. Step 3, the monolayer is transferred to a solid surface by dipping through the air-water interface. Multilayer films can be built up by repeated dipping through the interface.

Preparation methods to be used in organic thin film deposition can be roughly divided into two main categories quick and dirty deposition from solution and (ultra high) vacuum deposition from the gas phase, which is expensive and time-consuming but clean. In between lies the preparation of LB (Langmuir-Blodgett-) films of substituted amphiphilic molecules or unsubstituted molecules in mixed layers. 

---