Snyder Mark A, Lee J Alex, Davis Tracy M, Scriven L E, Tsapatsis Michael
Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, USA.
Langmuir. 2007 Sep 25;23(20):9924-8. doi: 10.1021/la701063v. Epub 2007 Jul 11.
Silica nanoparticles with a narrow particle size distribution and controlled diameters of 10-20 nm are synthesized via hydrolysis and hydrothermal aging of tetraethylorthosilicate in an aqueous L-lysine solution. Cryo-transmission electron microscopy (cryo-TEM) reveals that the silica nanoparticles assemble to form close-packed nanoparticle crystals over short length scales on carbon-coated grids. Evaporative drying of the same sols results in nanoparticle stability and remarkable long-range facile ordering of the silica nanoparticles over scales greater than 10 microm. Whereas small-angle X-ray scattering (SAXS) and small-angle neutron scattering (SANS) discount the possibility of a core (silica)-shell (lysine) structure, the possibility remains for lysine occlusion within the silica nanoparticles and concomitant hydrogen bonding effects driving self-assembly. Facile ordering of the silica nanoparticles into multilayer and monolayer coatings over square-centimeter areas by evaporation-induced self-assembly is demonstrated using a novel dip-coating device.
通过在L-赖氨酸水溶液中对原硅酸四乙酯进行水解和水热老化，合成了粒径分布窄、直径控制在10-20纳米的二氧化硅纳米颗粒。低温透射电子显微镜（cryo-TEM）显示，二氧化硅纳米颗粒在碳包覆网格上短长度尺度内组装形成密堆积纳米颗粒晶体。相同溶胶的蒸发干燥导致纳米颗粒稳定，并且在大于10微米的尺度上二氧化硅纳米颗粒具有显著的长程易序排列。虽然小角X射线散射（SAXS）和小角中子散射（SANS）排除了核（二氧化硅）-壳（赖氨酸）结构的可能性，但赖氨酸封闭在二氧化硅纳米颗粒内以及伴随的氢键效应驱动自组装的可能性仍然存在。使用一种新型浸涂装置证明了通过蒸发诱导自组装将二氧化硅纳米颗粒轻松有序地组装成平方厘米区域的多层和单层涂层。
