Morphology control of hollow Ni-P microfibers

In our previous paper [Trans. Mater. Res, Soc. Jpn. 29, 889 (2004)], we demonstrated that the macroscopic morphologies of hydrogen-bonded fibrous molecular assemblages formed from 6-[2-propyl-4-(4-pyridylazo)phenoxy]hexinoic acid could be controlled by four kinds of self-assembling methods. The four methods were categorized into (i) air neutralization, GO CO2 neutralization, (iii) crystal growth, and (iv) air neutralization with anionic surfactant. In this paper, we investigated the shapes of hollow Ni-P microfibers obtained through electroless plating from the four types of fibrous template materials. The following results were obtained. The inner diameter (500 nm) of the hollow Ni-P microfibers was almost identical to the outer diameter of the organic template microfibers prepared by (i) air neutralization. The Ni-P nanotubes having an outer diameter of 70 - 130 nm were formed using the template fibers prepared by (ii) CO2 neutralization. The hollow Ni-P microfibers having a range of 1 - 2 mu m in inner diameter were obtained from the template fibers by (iii) crystal growth. Ni-P nanotubes with rough surfaces were successfully obtained from template microfibers prepared by (iv) air neutralization with anionic surfactant of sodium dodecyl sulfate. We demonstrated that several types of hollow Ni-P microfibers with different morphology could be fabricated from one amphoteric compound. The formation mechanisms were proposed.