Detection of small polydispersities by photon correlation spectroscopy
Detection of small polydispersities by photon correlation spectroscopy
复制标题
通过光子相关光谱检测小多分散性
DOI：
10.1063/1.447195
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发表时间：
1984
影响因子：
4.4
通讯作者：
W. Megen
中科院分区：
文献类型：
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作者：
P. Pusey;W. Megen
我们考虑均匀多分散球形颗粒的稀悬浮液，瑞利-甘斯-德拜（RGD）近似是有效的。对于两种模型粒度分布，我们计算了平均散射强度I（Q）和有效扩散系数De（Q）对散射矢量Q的依赖性，其中有效扩散系数De（Q）是从光子相关光谱测量的第一累积量中获得的。如果平均颗粒半径R足够大（约170 nm），使得强度形状因子P（QR）在Q的可达范围内显示至少一个最小值，则我们发现De（Q）表现出对样品多分散性非常敏感的随Q的特征变化。在有利的条件下，应该可以测量多分散性（标准偏差/平均尺寸）小至0.01。这些理论上的考虑得到了实验的支持，至少是定性的支持。我们还简要讨论了放松的RGD近似的效果和这项工作的影响，更常见的PCS探针的PO…
We consider dilute suspensions of homogeneous polydisperse spherical particles for which the Rayleigh–Gans–Debye (RGD) approximation is valid. For two model particle size distributions we calculate the dependence on scattering vector Q of the average scattered intensity I(Q) and the effective diffusion coefficient De(Q) obtained from the first cumulant measured by photon‐correlation spectroscopy. If the mean particle radius R is large enough (≳170 nm) that the intensity form factor P(QR) shows at least one minimum in the accessible range of Q, we find that De(Q) exhibits a characteristic variation with Q which is very sensitive to the sample polydispersity. Under favorable conditions it should be possible to measure polydispersities (standard deviation/mean size) as small as 0.01. These theoretical considerations are supported, at least qualitatively, by experiment. We also discuss briefly the effect of relaxing the RGD approximation and the implications of this work for the more common PCS probes of po...