Morphology-tunable fibers with Fe3O4 nanocrystals fabricated through assembly.

A facile method has been developed to encapsulate Fe(3)O(4) nanocrystals (NCs) in morphology-tunable fibers (belt-like, solid, and tubal) by using a sonochemistry driven synthesis and a subsequent reflux procedure. By adapting the use of tetraethyl orthosilicate, ammonia, Cd(2+), and thiolglycolic acid (TGA) to an ultrasound-driven synthesis, the Fe(3)O(4) NCs were coated with a thin composite shell. Supersonic treatment plays an important role to prevent the agglomeration of the Fe(3)O(4) NCs in an alkaline condition. The composite shell became thicker due to the deposition of SiO(2) monomers, Cd-TGA clusters, Cd(2+), and free TGA molecules during reflux. In addition, these composite shell-coated Fe(3)O(4) NCs were assembled in composite fibers which were created by the growth of Cd-TGA clusters and the deposition of SiO(2) monomers. The Fe(3)O(4) NCs mono-dispersed in fibers revealed superparamagnetic behavior. The magnetic saturation value of tubal fibers is lower than those of belt-like and solid fibers. These fibers with Fe(3)O(4) NCs would be utilizable for further application. The strategy described here should give a useful enlightenment for the design and fabrication of morphology-tunable fibers with functional NCs.