1. Langmuir – Blodgett film
Sloviková Alexandra
Zajíčková Michaela

2. History 17th century First discovery of optic efect 19th century
The beginning of preparation of the thin layers
20th century (70th years)
The expansion of plasma technologies
20th century (80th years)
Development of Lamgmuir – Blodgett films

3. Why study molecular orientation in thin films?
interfacial properties
(optical, electronic and mechanical)
molecular interactions
organizational model for complex systems
Photoresist
“Chemically” cleaned
silicon wafer
Silicon oxide “barrier”
layer

4. Introduction
Langmuir – Blodgett films are monofilms or multifilms on solid substrate.
Molecules form a monolayer at the interface air-liquid
They are nanomaterials
The films are layers at scale 0,1 – 0,001 nm
~ 1 nm

5. Monolayer Phases
When the molecules are first spread on the water surface, they are loosely packed and form a so-called gas phase.
Increasing the surface pressure translates as a transition to a liquid phase.
Further increases in pressure bring about a last compressibility change that is associated to a liquid-solid phase transition.
Molecular area (nm2/molecule)
Surface pressure (mN/m)
Gas phase
Liquid phase
Solid phase

6. A barrier on the water surface pushes and compacts the molecules.
Spreading amphiphile molecules on a water surface yields monolayers or films where the hydrophobic segments stem at the water/air interface.
Films with tailored stability, orientation of molecules or phase transition can thereby be transferred to the substrate.

7. Characteristics of substrate
Hydrophilic:
Glass
Aluminium, chromium,
Wafer
Hydrophobic:
trimethylchlorsilane

8. Film transfer Water subphase Vertical Horizontal
This technique is actual for highly hydrophobic molecules.
Horizontal
This technique is suitable for transfer of very stif films.

9. Langmuir – Blodgett films
Vertically prepared films
3 types:
repeated submergence – type X
repeated emergence – type Z
switching both types – type Y X Z Y

11. References [1] doc.RNDr. Vladimír Čech, Ph.D. - Lectures
[2]
[3]
[4]
[5]