Molecular self-assembly of long-chain alcohols, thiols, and carboxylic acids on a single substrate via acid-base hydrolytic chemistry.

摘要

This thesis reports a novel route to molecular self-assembly based on simple acid-base hydrolytic chemistry involving the reactions of aminosilanes with organic species containing acidic protons. From detailed solution chemistry of trimethyl-, trimethoxy-, and triphenyl-chloro/amino-silanes, two general processes have been developed for the self-assembly of long alkyl chain terminated alcohols, thiols, and carboxylic acids on inorganic oxide surfaces i.e., glass, quartz and single crystal silicon. The first method involves three successive reactions with the surface moieties where the initially formed silylchloride layer is converted to a silylamine, which is then reacted further to give the organic monolayers. The second method involves a single reaction of the surface with surfactant species formed first by reacting trimethoxysilylchloride with the appropriate chromophore. The chemistry and comparative advantages of these two methods are discussed. A discussion on the complete characterization of newly formed thin films by employing surface techniques, such as wettability, FTIR-ATR spectroscopy, ellipsometry, and X-ray reflectivity, is provided. These results indicate that thin films formed using simple acid-base hydrolytic chemistry are comparable to those obtained from more established techniques, such as trichlorosilanes on glass, thiols on gold, and carboxylic acids on silver or alumina. The results presented in this thesis demonstrate that the acid-base hydrolytic chemistry is a viable and widely applicable method to molecular self-assembly and can be considered as a unifying approach to literature methods.