What is meant by self-assembled monolayer?
A Self-Assembled Monolayer (SAM) is a one molecule thick layer of material that bonds to a surface in an ordered way as a result of physical or chemical forces during a deposition process. Silanes can form SAMs by solution or vapor phase deposition processes.
What material is typically used as the head group in a self-assembled monolayer?
Substrates can be planar surfaces, such as silicon and metals, or curved surfaces, such as nanoparticles. Alkanethiols are the most commonly used molecules for SAMs. Alkanethiols are molecules with an alkyl chain, (C-C)ⁿ chain, as the back bone, a tail group, and a S-H head group.
How are self-assembled monolayers formed?
Figure 1 Self-assembled monolayers are formed by simply immersing a substrate into a solution of the surface-active material. The driving force for the spontaneous formation of the 2D assembly includes chemical bond formation of molecules with the surface and intermolecular interactions.
Why is gold surface preferred to prepare movies by Sam?
Gold substrates are so far the most used and studied substrate for the formation of carbohydrate SAMs not only because they are capable of supporting stable SAMs due to Au‐S bonding but also due to their conductivity, chemical and physical stability, and biocompatibility.
Which is the best description of a monolayer?
A monolayer is a single, closely packed layer of atoms, molecules, or cells. In some cases it is referred to as a self-assembled monolayer. Monolayers of layered crystals like graphene and molybdenum disulfide are generally called 2D materials.
Why are self assembled monolayers of noble metals special?
Self-assembled monolayers of thiolates on noble metals are a special case because the metal-metal bonds become reversible after the formation of the thiolate-metal complex. This reversibility is what gives rise to vacancy islands and it is why SAMs of alkanethiolates can be thermally desorbed and undergo exchange with free thiols.
How are Langmuir monolayers used in LB films?
Chemistry. Langmuir monolayers are extensively studied for the fabrication of Langmuir-Blodgett film (LB films), which are formed by transferred monolayers on a solid substrate. A Gibbs monolayer or soluble monolayer is a monolayer formed by a compound that is soluble in one of the phases separated by the interface on which the monolayer is formed.
What kind of spectroscopic techniques are used in self assembled monolayer?
Numerous other spectroscopic techniques are used such as Second-harmonic generation (SHG), Sum-frequency generation (SFG), Surface-enhanced Raman scattering (SERS), as well as High-resolution electron energy loss spectroscopy (HREELS).
