Molecular Self-Assembly of Dihydroxy-Terminated Molecules via Acid−Base Hydrolytic Chemistry on Silica Surfaces:  Step-by-Step Multilayered Thin Film Construction

Acid−base hydrolytic chemistry of aminosilanes with dihydroxy-terminated molecules containing rigid-rod type and alkyldiacetylene backbones, has been used to construct thin films on Si(100) (Si/SiO2) substrates. A layer-by-layer construction methodology using Si(NEt2)4 and 2,4-hexadiyne-1,6-diol or 5,7-dodecadiyne-1,12-diol leads to multilayered supramolecular structures. The quality of thin films in this step-by-step deposition process was monitored by contact angle goniometry, ellipsometry, Fourier transform infrared−attenuated total reflection, X-ray photoelectron, and UV−vis absorption spectroscopies. The results indicate that diol-terminated chromophores form good quality, relatively closely packed thin films on silicon(silica) surfaces. Multilayered thin film construction enhances the stability of the thin films under varied conditions. The thin film assemblies were subjected to topochemical polymerization, and upon UV−vis exposure, the formation of a blue film was observed.