纳米颗粒定向运动对动态光散射测量结果的影响

Influence of directional motion of nano-particles on dynamic light scattering measurements

为探究溶液定向运动对动态光散射测量结果的影响,采用动态光散射测量系统对不同流速下的纳米颗粒进行测量。结果表明:当定向运动速度矢量与散射矢量垂直时,自相关曲线基本不变;当定向运动速度矢量与散射矢量呈某一夹角时,流速越大,自相关曲线衰减越快;在某一特定运动速度下,夹角越小,相关曲线的衰减越快;用有限入射光束宽度下的动态光散射理论可解释上述实验结果。

In order to study the influence of directional motion of nano-particles on dynamic light scattering measurements, we measured the nano-particles with different velocity using the measurement system of dynamic light scattering. The results show that the measured auto-correlation function is almost invariant when the directional velocity is perpendicular to the scattering wave vector. However, when the directional velocity and the scattering wave vector are not perpendicular, the decay of the auto-correlation function becomes faster as the directional velocity becomes larger. When the velocity is fixed, the angle between the velocity and the scattering vector is smaller and the decay of the function is faster. These results agree well with the theory of the dynamic light scattering when the waist of the incident light is limited.