In situ molecular composites of ladder polyphenylsilsesquioxane and polyisophthalamide and their electro-spinning fibers

The molecular composites of ladder polyphenylsilsesquioxane (Ph-LPSQ) and alkoxy substituted polyisophthalamide (Cn-PA) are in situ prepared for the first time by supramolecular template directed synchronous two-step synthesis, mainly including (A) self-assembled ladder superstructure-based synchronous growth polymerization of the silylated diaminophenylene-bridged ladder polyphenylsiloxane (Ph-DLPS) and (B) isophthalylchloride (IPC)-induced synchronous cleavage of the silylated diaminophenylene-bridge and in situ dehydrochlorination condensation. Moreover, novel composite fibers with sub-μm level diameters are prepared by electro-spinning and their morphologies are investigated by SEM. In order to improve the spinning capability, alkoxy groups in different lengths are introduced into the benzene ring of IPC to produce alkoxy substituted polyisophthalamide (Cn-PA). The fiber-forming ability and the morphology of the resulting electro-spun fibers depend strongly on the solvents used, solution concentration and lengths of the alkoxy groups. Uniform continuous fibers of Cn-PA/Ph-LPSQ are spun from chloroform solution. The longer side chains can result in the formation of a fiber with a smaller diameter. The molecular composition mechanism of Ph-LPSQ and Cn-PA is, in particular, examined using FT-IR spectroscopy, indicating that the hydrogen bond between the amide groups of Cn-PA and Si–O–Si bonds of Ph-LPSQ plays a decisive role in their uniform compounding.