| A novel in situ template approach to polymer nanotubes was developed, via which cyclomatrix-type poly(cyclotriphosphazene-co-4,4'-sulfonyldiphonel) (PZS) nanotubes were prepared. Under ultrasonic condition, triethylammonium chloride (TEACl) crystals were formed to act as in situ templates during the polycondensation between hexachlorocyclotriphosphazene (HCCP) and 4,4'-sulfonyldiphenol (BPS). The preparation of PZS nanotubes was simple and easy to scale up, so did the post treatment. 1H NMR monitor of the polycondensation showed that TEA acted as not only acid-acceptor but also catalyst to activate BPS for nucleophilic substitution. And condensation between HCCP and BPS followed a bimolecular nucleophilic substitution (S_N2) pattern. The dimensions of PZS nanotubes could be controlled in a diameter range of 5-10 nm or 10-20 nm, lengths of 1-2μm or more than 5μm, tips of open-ends and close-ends by varying reaction conditions. PZS nanotubes had a molecular structure of highly cross-linked cyclo-matrix.TEM analysis confirmed the formation process of PZS nanotubes: during the polycondensation, highly cross-linked PZS nano-particles and TEACl nano-crystals were first precipitated out of the reaction medium, PZS nano-particles then adhered onto the surfaces of TEACl nano-crystals to form core-shell structures, finally, after removal of the TEACl templates...
|
PDF Full Text Request