Preparation and characterisation of calcium citrate wires

Long calcium citrate wires were successfully prepared using a convenient and effective soft chemical method that involved heating the sheet precursor at an appropriate temperature in a mixture of alcohol and water for a sufficient amount of time. The X-ray diffraction patterns showed that the crystallinity degree increased with heating time. Moreover, the (200) crystal plane was the preferential growth face that was influenced by alcohol. Such influence was ascribed to alcohol being able to change the free energy and the supersaturation state of the solution. In addition, alcohol might adsorb onto the surface of the crystal and change the growth velocity of each crystal plane. The sheet precursor progressively turned into consecutive long wires by growing along the preferential growth orientation during the dissolution-reprecipitation process. The thickness of the wires was ~8-30 nm. Long calcium citrate wires were produced to reinforce and strengthen biomaterials or for other purposes.