IFP Energies nouvelles, Rueil-Malmaison, France.
J Phys Chem B. 2011 Jun 2;115(21):6827-37. doi: 10.1021/jp111468d. Epub 2011 May 10.
Complementary neutron and X-ray small angle scattering results give prominent information on the asphaltene nanostructure. Precise SANS and SAXS measurements on a large q-scale were performed on the same dilute asphaltene-toluene solution, and absolute intensity scaling was carried out. Direct comparison of neutron and X-ray spectra enables description of a fractal organization made from the aggregation of small entities of 16 kDa, exhibiting an internal fine structure. Neutron contrast variation experiments enhance the description of this nanoaggregate in terms of core-shell disk organization, giving insight into core and shell dimensions and chemical compositions. The nanoaggregates are best described by a disk of total radius 32 Å with 30% polydispersity and a height of 6.7 Å. Composition and density calculations show that the core is a dense and aromatic structure, contrary to the shell, which is highly aliphatic. These results show a good agreement with the general view of the Yen model (Yen, T. F.; et al. Anal. Chem.1961, 33, 1587-1594) and as for the modified Yen model (Mullins, O. C. Energy Fuels2010, 24, 2179-2207), provide characteristic dimensions of the asphaltene nanoaggregate in good solvent.
互补的中子和 X 射线小角散射结果为沥青质的纳米结构提供了重要信息。在相同的稀甲苯沥青质溶液上进行了大范围 q 值的精确 SANS 和 SAXS 测量，并进行了绝对强度定标。中子和 X 射线光谱的直接比较能够描述由 16kDa 小实体聚集而成的分形组织，具有内部精细结构。中子对比变化实验增强了对这种纳米聚集体的描述，揭示了核和壳的尺寸和化学成分。纳米聚集体最好用总半径为 32Å、多分散度为 30%和高度为 6.7Å的圆盘来描述。组成和密度计算表明，与壳相比，核是一个致密的芳香结构，而壳则高度脂肪族。这些结果与 Yen 模型（Yen，TF；等人。分析化学。1961, 33, 1587-1594）的总体观点一致，与改进后的 Yen 模型（Mullins，OC。能源燃料。2010, 24, 2179-2207）一致，为良溶剂中沥青质纳米聚集体的特征尺寸提供了依据。
