| A new route to molecular self-assembly using a simple acid-base hydrolytic approach on silica based surfaces, is reported in this thesis. Based on this methodology, a number of compounds containing terminal groups with acidic protons, such as alcohols, thiols, carboxylic acids, and terminal alkynes, can be easily deposited on silica surfaces. The quality of the thin films was monitored by contact angle goniometry, ellipsometry, XPS, FTIR-ATR and UV-Vis absorption spectroscopies. The deposition conditions were optimized to produce ordered and densely packed mono- and multilayers. Using the two-step process, self-assembled monolayers (SAMs) of a variety of long chain alcohols containing terminal alkyl, phenyl and acetylene groups on silica surfaces were successfully prepared. The newly formed monolayers were found to be relatively ordered and densely packed. They showed comparable stabilities to OTS/SiO 2 at ambient and high temperatures, and upon treatment with acids and bases. A layer-by-layer construction methodology, based on acid-base hydrolysis of aminosilanes and dihydroxy terminated molecules containing rigid-rod type and alkyldiacetylene backbones, led to multilayers with higher stability under various conditions compared to monolayers. The thin film assemblies were subjected to topochemical polymerization, and upon UV-Vis exposure, the formation of a blue film was observed.;Using the acid-base hydrolytic chemistry approach, silica surfaces functionalized with Sn-NEt2 groups can be easily modified using a number of terminal alkyne molecules with varied backbones. SAMs of a variety of rigid-rod alkynes on silica surfaces were successfully prepared. The pi-pi interactions in the molecules lead to ordered and densely packed thin film structures with a surface coverage of 2--7 molecules/100 A 2. The thin film assembly with diacetylene backbone was also subjected to topochemical polymerization, and upon UV-Vis exposure, the formation of a blue film was observed. Furthermore, a layer-by-layer construction methodology using aminostannanes and dialkyne terminated molecules containing alkyl or aromatic type backbone led to multilayered structures on silica surfaces without increasing disorder in the thin films with the increase in number of layers. The acetylene groups in the thin film assemblies were found to coordinate with cobalt carbonyl, corroborated by the observation of lambdamax at 277 nm. |
