A study on structures and formation mechanisms of self-assembled monolayers of n-alkyltrichlorosilanes using infrared spectroscopy and atomic force microscopy

The structures and formation mechanisms of self-assembled monolayers of n-alkyltrichlorosilanes on glass substrates have been examined systematically using Fourier transform infrared spectroscopy (FTIR) and atomic force microscopy (AFM). The adsorption temperature dependency of FTIR frequencies and intensities of CH 2 stretching vibration bands indicates the existence of a characteristic temperature, T c , for each monolayer. The hydrocarbon chains observe an ordered and closely packed state when the monolayers are prepared below T c , whilst disordered monolayers with low molecular density are formed above T c . AFM observation clearly demonstrates an island-type growth of monolayers prepared below T c . The results obtained contribute to an understanding of the growth behavior of the monolayers and the physical meaning of the T c .