Sergiy Peleshanko

Langmuir-Blodgett monolayers from lower generation amphiphilic monodendrons

Abstract Amphiphilic monodendrons of lower generations, AD12-N, containing a benzyl-15-crown-5 polar focal point, photochromic spacer and different number of dodecyl tails as peripheral groups ( n =1–8) have been investigated for their ability to form uniform monolayers at solid surfaces. The surface pressure–area behavior, photomechanical behavior and the morphology of the monomolecular films were investigated. We observed that all compounds studied are capable of forming stable Langmuir and Langmuir Blodgett monolayers, with virtually flat packing of molecules. Higher generation dendrimers form very uniform monolayers, without the usual domain microstructure. For AD12-4 monolayer on solid support, we observed stripped microstructure with several layers (3–6) bundled together. The periodicity of this structure of 8 nm was close to layered spacing, obtained from X-ray data for bulk material. For this compound, we proposed the model of double-layered packing of the molecules, with partial overlapping of the central segments and suggested that deposition on a solid substrate resulted in changing orientation of molecular fragments. Fast reversible photochromic response was observed for all monolayers with a conversion level of 50%.