Preparation of Highly Crystalline Octavinyl Silsesquioxane Building Blocks via Sol-Gel Technique

Polyhedral oligomeric silsesquioxanes (POSSs) are a class of hybrid materials with a unique structure and properties originated from a combination of organic functional groups and inorganic silica core. Not welldefined synthesis process generally suffers from multistep, complex and especially timeconsuming procedure from days to weeks and months. Consequently, in the present study, the effect of various parameters on the synthesis of octavinyl POSS (OV-POSS) nanostructure such as temperature, monomer concentration, reaction time, and rate of monomer addition are investigated. Finally, OV-POSS crystallization is produced under optimal condition through singlestep hydrolytic condensation of vinyltrimethoxysilane (VTMS) with 72% yield and a high crystallinity (above 90%) during a reduced time interval of 5 h at 60 °C at a 20 μl.min^-1 monomer addition rate. Morphology and size of the as-prepared samples are characterized using Xray diffraction (XRD), field emission scanning electron microscopy (FESEM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses. Also, the chemical structure is predicted using nuclear magnetic resonance (NMR), FTIR, and EDX.