采用短碳链的表面活性剂溴代十二烷基三甲基溴化铵为模板剂，合成了具有较大粒径和超小孔径分布的单分散树枝状介孔二氧化硅纳米球(记为DMSNs-C12)。通过扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射能谱(XRD)、傅里叶变换红外光谱(FT-IR)、以及氮气吸附脱附曲线对制备的DMSNs-C12进行了形貌、晶体结构、化学组成、孔体积、比表面积等分析。结果表明：与传统的、以溴代十六烷基三甲基溴化铵为模板剂制备的单分散树枝状二氧化硅纳米球相比(DMSNs-C16)，DMSNs-C12颗粒尺寸明显增大，褶皱结构消失，孔道尺寸急剧减小。原因是随着碳链减小，表面活性剂相互斥力减弱，影响微乳液形成，最终导致结构差异。

Monodisperse dendritic mesoporous silica nanospheres (DMSNs) with enlarged diameter and extremely tiny pore size were synthesized by brominated dodecyl trimethyl ammonium bromide which is a relatively short carbon chain surfactant and acts as template agent. The as-prepared DMSNs-C12 were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), Fourie tansform infrared spectroscopy (FT-IR), N2 adsorption-desorption isotherms to reveal its morphology, crystal texture, chemical compositions, pore volume and specific surface area. The results indicate that the particle size of DMSNs-C12 greatly increases, wrinkled structure disappears and the pore size significantly declines, compared with DMSNs fabricated with conventional cetlytrimethyl ammonium bromide as emplate agent (noted as DMSNs-C16). The reason could be that the mutual repulsive force of surfactants decreases with the reduction of carbon chain which affects microemulsion formation, giving rise to structural difference.