Braun Birgit, Dorgan John R, Chandler John P
Department of Chemical Engineering, Colorado School of Mines, Golden, Colorado 80401, USA.
Biomacromolecules. 2008 Apr;9(4):1255-63. doi: 10.1021/bm7013137. Epub 2008 Mar 22.
Mathematical treatment of light scattering within the Rayleigh-Gans-Debye limit for spheroids with polydispersity in both length and diameter is developed and experimentally tested using cellulosic nanowhiskers (CNW). Polydispersity indices are obtained by fitting the theoretical formfactor to experimental data. Good agreement is achieved using a polydispersity of 2.3 for the length, independent of the type of acid used. Diameter polydispersities are 2.1 and 3.0 for sulfuric and hydrochloric acids, respectively. These polydispersities allow the determination of average dimensions from the z-average mean-square radius (<S(2)>z) and the weight-average molecular weight (M w) easily obtained from Berry plots. For cotton linter hydrolyzed by hydrochloric acid, the average length and diameter are 244 and 22 nm. This compares to average length and diameter of 272 and 13 nm for sulfuric acid. This study establishes a new light-scattering methodology as a quick and robust tool for size characterization of polydisperse spheroidal nanoparticles.
针对长度和直径均具有多分散性的椭球体，在瑞利 - 甘斯 - 德拜极限范围内开展了光散射的数学处理，并使用纤维素纳米晶须（CNW）进行了实验测试。通过将理论形状因子拟合到实验数据来获得多分散指数。对于长度，使用2.3的多分散性可实现良好的一致性，且与所用酸的类型无关。硫酸和盐酸的直径多分散性分别为2.1和3.0。这些多分散性使得能够根据从贝里图中轻松获得的z - 平均均方半径（<S(2)>z）和重均分子量（Mw）来确定平均尺寸。对于用盐酸水解的棉短绒，平均长度和直径分别为244和22 nm。相比之下，硫酸水解的平均长度和直径为272和13 nm。本研究建立了一种新的光散射方法，作为一种快速且强大的工具，用于多分散球形纳米颗粒的尺寸表征。
