Pluronic 123-templated mesoporous SBA-15 silica rods with a length of ca. 3.0–4.0 μm were easily synthesized in a dilute silicate solution with a pH value of 2.0 at room temperature. Through a good control on the synthetic condition and the chemical components, a high homogeneity (>95%) of the hexagonal SBA-15 silica rods can be achieved. In addition, the effect of the synthetic conditions including acid source, weight ratio of the P123/sodium silicate, temperature, water content, pH value, and applying shearing flow were explored in detail to tailor the morphologies of the SBA-15 mesoporous silicas. In this paper, we also focused on the counterion effect on the synthesis of the SBA-15 mesoporous silicas. It was found that the SO42− counterion from H2SO4 has higher affinity to induce the formation of P123 rod-like micelles than that of Cl−, NO3−. Meanwhile, we postulated that the self-assembly pathway of the silica species and the neutral tri-block copolymer micelles in a dilute solution with a pH value of 2.0 would occur through an S0···I0 rather than the S0X−…I+ one as previously discussed. We further employed the SAB-15 mesoporous silica rods as the templates to synthesize high-quality CMK-3 mesoporous carbon rods by using commercially available phenol–formaldehyde (PF) resin as the carbon source.
This is a preview of subscription content, log in to check access.
Authors thank Chung-Chun Plastic, Taiwan, for providing PF polymers. This research is financially supported by National Science Council of Taiwan (NSC95-2113-M-006-011-MY3 and NSC95-2323-B-006-008) and Taiwan Textile Research Institute and Landmark Project from National Cheng Kung University (R017).