Surface-monolayer-controlled molecular alignment of short n-alkane multilayers

C K-edge near-edge X-ray absorption fine structure studies have been performed on the molecular orientation of short n-alkane (C₆H₁₄) multilayers on n-alkanethiolate (C₆H₁₃S) monolayers. We have found that the molecular orientation of the n-alkane multilayers is in accordance with that of n-alkanethiolate monolayers on which the multilayers were formed. Monolayers of thiophene also have a significant effect on the alignment of the n-alkane multilayers condensed on the monolayers. The growth manner of the n-alkane films is discussed in terms of the energy balance between surface and interface free energies.