Synthesis of mesoporous silica nanofibers with controlled pore architectures
Synthesis of mesoporous silica nanofibers with controlled pore architectures
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DOI：
10.1021/cm049028q
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发表时间：
2004-11-30
影响因子：
8.6
通讯作者：
Stucky, GD
中科院分区：
文献类型：
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作者：
Wang, JF;Tsung, CK;Stucky, GD
在强酸性条件下，利用阳离子表面活性剂，采用单相法合成了具有可控内部孔结构的介孔二氧化硅纳米纤维。纤维的直径范围为50 - 250 nm，长度可达毫米。纳米纤维可以具有纵向孔结构，其中孔通道平行于纤维轴排列，或者具有圆形孔结构，其中孔通道围绕纤维轴圆形缠绕。两种类型的纳米纤维中的孔道都是六边形堆积的。具有纵向孔结构的纳米纤维的横截面为六边形，具有圆形孔结构的纳米纤维的横截面为圆形。进行了系统的实验，其中，对于十六烷基三甲基氯化铵（C（16）TMAC）、十六烷基三甲基溴化铵（C（16）TMAB）、十六烷基氯化吡啶（C16 PC）和十六烷基溴化吡啶（C16 PB）表面活性剂，将具有圆形孔结构的纳米纤维在整个纳米纤维中的分数确定为生长温度的函数。通常，较低的温度产生具有纵向孔结构的纳米纤维，较高的温度产生具有圆形孔结构的纳米纤维。C-16-TMAC和C16 TMAB表面活性剂的转变温度约为75 ℃，C16 PC和C16 PB表面活性剂的转变温度约为55 ℃。此外，用不同尾长的阳离子表面活性剂，包括十二烷基三甲基溴化铵（C（12）TMAB）、十四烷基三甲基溴化铵（C（14）TMAB）和十八烷基三甲基溴化铵（C（18）TMAB）进行了一相合成。用C（12）TMAB或C（14）TMAB表面活性剂合成没有获得纳米纤维，而用C（18）TMAB表面活性剂合成的产物中大于95重量%是在40 - 90 ℃的温度范围内具有纵向孔结构的纳米纤维。此外，在生长过程中掺入罗丹明6G（Rh6G）染料分子，以制备毫米长的介观结构纳米纤维，并且沿单个纤维的整个长度沿着均匀地发荧光。
A one-phase route has been developed for the synthesis, under strongly acidic conditions with cationic surfactants, of mesoporous silica nanofibers with controlled internal pore architectures. The diameters of the fibers range from 50 to 250 nm, and the lengths are up to millimeters. The nanofibers can have either a longitudinal pore architecture, in which the pore channels are aligned parallel to the fiber axis, or a circular pore architecture, in which the pore channels are wound circularly around the fiber axis. The pore channels in both types of nanofibers are hexagonally packed. The cross sections of the nanofibers with longitudinal pore architectures are hexagonal and those of the nanofibers with circular pore architectures are circular. Systematic experiments were carried out in which the fraction of the nanofibers with circular pore architectures among the overall nanofibers was determined as a function of the growth temperature for hexadecyltrimethylammonium chloride (C(16)TMAC), hexadecyltrimethylammonium bromide (C(16)TMAB), hexadecylpyridinium chloride (C16PC), and hexadecylpyridinium bromide (C16PB) surfactants. Generally, lower temperatures produce nanofibers with longitudinal pore architectures and higher temperatures produce nanofibers with circular pore architectures. The transition temperatures for C-16-TMAC and C16TMAB surfactants are around 75 degreesC and those for C16PC and C16PB surfactants are around 55 degreesC. In addition, the one-phase synthesis was carried out with cationic surfactants of different tail lengths, including dodecyltrimethylammonium bromide (C(12)TMAB), tetradecyltrimethylammonium bromide (C(14)TMAB), and octadecyltrimethylammonium bromide (C(18)TMAB). No nanofibers are obtained from the synthesis with C(12)TMAB or C(14)TMAB surfactants, while greater than 95 wt % of the products from the synthesis with C(18)TMAB surfactant are nanofibers with longitudinal pore architectures in the temperature range of 40-90 degreesC. Furthermore, rhodamine 6G (Rh6G) dye molecules were incorporated during growth to make mesostructured nanofibers that are millimeters long and fluoresce uniformly along the entire length of the individual fiber.