Liquid mechanical behavior of mixed monolayers of amino and alkyl silanes by atomic force microscopy.
The adsorption of mixed terminally aminated organosilyl compounds with long-chain n-alkyltrichlorosilanes on silica substrates has been studied by FTIR and AFM to deposit and study DNA. By optimization of deposition conditions, the mixed monolayers were found to be well organized and homogeneous. The amino group was protected to obtain a reproducible grafting and then deprotected after the film formation. In addition, atomic force microscopy (AFM) studies in both dynamical modes, amplitude modulation and frequency modulation, reveal that the layer behaves as a fluid as measured by the tip-cantilever and has a smaller characteristic time than the tip-cantilever. For three amplitudes, the experimental frequency shifts have been modeled for a fluidlike layer crossed by the tip. Finally, we show that this new fluidlike monolayer is suitable for DNA deposition and AFM studies.
Martin
Pascal
P
Centre de Physique Moléculaire Optique et Hertzienne, UMR 5798 CNRS, Université Bordeaux 1, 351 cours de la Libération, 33405 Talence Cedex, France.
Marsaudon
Sophie
S
Thomas
Laurent
L
Desbat
Bernard
B
Aimé
Jean-Pierre
JP
Bennetau
Bernard
B
D018625:Microscopy, Atomic Force / Q000379:methods*; D012821:Silanes / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
D012821:Silanes