Stepwise adsorption of a long trichlorosilane and a short aminosilane

A mixed film of microscopic heterogeneity was formed by stepwise deposition of a long-chain organosilane n-octadecyltrichlorosilane (OTS) and a short- chain organosilane aminobutyldimethylmethoxysilane (ABS). The amount of sil ane deposited on an oxidized silicon substrate was controlled kinetically b y varying the dip time in each silane solution. The binary film was charact erized by the atomic force microscopy (AFM), infrared attenuated total inte rnal reflection (IR-ATR), and contact angle goniometry. OTS forms a monolay er structure whose fractional surface coverage and surface energy can be pr ecisely controlled. ABS agglomerates slowly to form island structure and is ineffective in surface energy or composition variation. The contact angles on sub-monolayers of OTS follows the Cassie equation, while the contact an gle of the binary OTS and ABS film deviates positively from the equation. ( C) 2000 Elsevier Science B.V. All rights reserved.