Hierarchical Trimodal Porous Hydroxyapatite Fabricated by Colloidal Crystal Templating Using Single-Size Latex Particles

Hierarchical trimodal porous hydroxyapatite (tpHAP) was fabricated by colloidal crystal templating using single-size latex particles with controlled calcination. In the overall framework structure, the tpHAP was revealed to have three kinds of pores, i.e., periodically ordered submicrometer-sized macropores of inverse opal structure, sponge-like larger macropores, and mesopores. The sponge-like macropores should be formed through removal of a sacrificial latex template, which fused in the process of low-temperature calcination. It was also found that high-temperature calcination leads to an increase in the crystallinity of the tpHAP, which resulted in deterioration of the ordered macropore arrays and a decrease in specific surface areas. Because of the trimodal porous structure, the tpHAP will serve as a multifunctional porous bioceramic in the fields of medical implants, tissue engineering, and drug delivery systems.