Gupta Sudipta, Bleuel Markus, Schneider Gerald J
Department of Chemistry and Department of Physics, Louisiana State University, Baton Rouge, Louisiana 70803, USA.
NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA.
Rev Sci Instrum. 2018 Jan;89(1):015111. doi: 10.1063/1.5021370.
Ultrasound irradiation is a commonly used technique for nondestructive diagnostics or targeted destruction. We report on a new versatile sonication device that fits in a variety of standard sample environments for neutron and X-ray scattering instruments. A piezoelectric transducer permits measuring of the time-dependent response of the sample in situ during or after sonication. We use small-angle neutron scattering (SANS) to demonstrate the effect of a time-dependent perturbation on the structure factor of micelles formed from sodium dodecyl sulfate surfactant molecules. We observe a substantial change in the micellar structure during and after exposure to ultrasonic irradiation. We also observe a time-dependent relaxation to the equilibrium values of the unperturbed system. The strength of the perturbation of the structure factor depends systematically on the duration of sonication. The relaxation behavior can be well reproduced after multiple times of sonication. Accumulation of the recorded intensities of the different sonication cycles improves the signal-to-noise ratio and permits reaching very short relaxation times. In addition, we present SANS data for the micellar form factor on alkyl-poly (ethylene oxide) surfactant molecules irradiated by ultrasound. Due to the flexibility of our new in situ sonication device, different experiments can be performed, e.g., to explore molecular potentials in more detail by introducing a systematic time-dependent perturbation.
超声辐照是一种常用于无损诊断或靶向破坏的技术。我们报道了一种新型多功能超声处理装置，它适用于多种用于中子和X射线散射仪器的标准样品环境。压电换能器允许在超声处理期间或之后原位测量样品随时间的响应。我们使用小角中子散射（SANS）来证明随时间变化的扰动对由十二烷基硫酸钠表面活性剂分子形成的胶束结构因子的影响。我们观察到在暴露于超声辐照期间和之后胶束结构发生了显著变化。我们还观察到向未受扰动系统的平衡值的时间依赖性弛豫。结构因子的扰动强度系统地取决于超声处理的持续时间。多次超声处理后，弛豫行为可以很好地重现。不同超声处理循环记录强度的累积提高了信噪比，并允许达到非常短的弛豫时间。此外，我们展示了超声辐照的烷基聚环氧乙烷表面活性剂分子胶束形状因子的SANS数据。由于我们新型原位超声处理装置的灵活性，可以进行不同的实验，例如，通过引入系统的随时间变化的扰动来更详细地探索分子势。
