Polycondensation and carbonization of phenolic resin on structured nano/chiral silicas: reactions, morphologies and properties

In this research, we extended a bioinspired and templated synthesis way for SiO2 to carbonaceous materials, with the success in morphology control and inducing chirality at the nano-scale. The biopolymer-analogue polyamine, i.e., polyethyleneimine (PEI) was employed as a catalytic template for SiO2 formation, and the as-formed PEI@SiO2 hybrids, which combine the rigidity of SiO2 and the chemical activity of PEI, were further used as hard-templates and basic catalysts for the deposition of phenolic resin on PEI@SiO2 under mild conditions. Through further carbonization and etching SiO2, SiO2/carbon composites and carbonaceous materials were produced, respectively. After characterization of these products by SEM, TEM, XPS, Raman spectroscopy, FT-IR, and TG-DTA, it was demonstrated that the morphologies were well transmitted in these successive steps. By taking advantage of the diverse modulation ways on the morphologies and structures of initial PEI templates, it is easy to achieve SiO2/carbon and carbonaceous products with different morphologies, including nanofibrils, nanobelts, and nanotubes. Moreover, this process could also fulfill a steady chirality transmission. When PEI complexed with chiral tartaric acid, the resulting chiral complex could function both as a template and chirality source, and finally chiral nanostructured carbonaceous products were obtained.