Study of the dynamic structure of microphase separation by X-ray small angle scattering using the CCD type X-ray detector

不同条件下，嵌段共聚物的层状结构取向在振荡剪切下表现出不同的行为。例如，在振荡剪切作用下，聚苯乙烯-聚异戊二烯两嵌段共聚物的片层结构是垂直、平行或横向的，这取决于其频率、幅度和温度。取向行为还依赖于振荡剪切的时间过程。如果阐明了这种行为的基本机制，就可以定制这种行为，以便设计新的力学特性。因此，研究纳米尺度结构(分子结构)与振动剪切条件(频率、温度、应变)之间的关系具有重要意义。在本研究中，我们研制了一种高灵敏度的CCDX射线探测器，使我们能够以亚秒的时间分辨率记录时间分辨的小角X射线散射图。接下来，我们研制了一台剪切机，在对聚合物样品施加振荡剪切的同时，可以让X射线束以不同的三个垂直方向通过。结合上述装置，我们利用同步辐射时间分辨小角X射线散射技术，成功地观察到了振荡剪切作用下聚苯乙烯-聚异戊二烯嵌段共聚物中片层结构的取向行为。

The orientation of lamellar structure in block copolymers behaves differently under oscillatory shear with different conditions. For example, the lamellar structure of polystyrene-polyisoprene di-block copolymer is orientated in either perpendicular or parallel or transverse under oscillatory shear, depending on its frequency and its amplitude and temperature. The orientation behavior is also dependent on time course of the oscillatory shear. If the underlying mechanism of this behavior is clarified, this behavior is tailored so that new mechanical properties can be designed. Therefore, it is important to investigate the relation of nano-scale structure (molecular structure) and oscillatory shear condition (frequency, temperature, strain ).In this study, we have developed a high-sensitivity CCD X-ray detector which enables us to record time-resolved small-angle X-ray scattering patterns with a sub-second time resolution. Next, we have developed a shearing machine which may let an X-ray beam pass through with different three orthogonal directions while applying oscillatory shear to polymer sample. With the above apparatus combined, we have successfully observed the orientation behavior of the lamellar structure in block copolymer of polystyrene and polyisoprene under oscillatory shear with time-resolved small angle X-ray scattering technique using synchrotron radiation.