Mechanism of Self-organized micro structures during Photoreaction

我们已经成功地制造了具有10微米的微剥离图案的薄膜，其显示出对光透明度的视角依赖性，平均保持90%的光透明度。这种微米级结构不是由于微相分离，而是由于光反应过程中的自组织。其应用前景广泛，如：视角调节膜、液晶显示器扩散膜、光导膜等。为了提高薄膜的透光性和减薄性能，研究了光反应过程中的自组织机理。以下是明确发现。（1）结构的形成发生在中等光强下。（2）在一定浓度的自由基反应引发剂下，结构的形成发生。（3）通过显微拉曼分析，观察到了具有光反应转换调制的有序条纹图案。（4）凝胶化后的结构在光反应的最大程度上被固定。下面从光反应的角度讨论我们对该机理的理解。本文提出的最现实的机理是，由光反应产生的微凝胶由于光散射而增强了不均匀的光强度。光反应的动力学常数在光强度方面示出了具有拐点的S形函数，该拐点负责将光强度分布分成强场和弱场。

We have succeeded to fabricate the thin films having micro stripped patterns of 10 micron which show eye-angle dependency on light transparency with keeping 90 % light transparency as average. This micron order structure is not due to micro phase separation but due to self-organization during photoreaction. The applications are widely expected as following ; eye-angle regulated films, diffusion films of liquid crystal displays, and light guiding films. In order to improve the performance of light transparency and thinner films, the mechanism of self-organization during photoreaction has been studied. The followings are clearly found.(1)The structure formation takes place under moderate light intensity.(2)The structure formation takes place under a certain concentration of radical reaction initiator.(3)The ordered stripped patterns with modulation of photoreaction conversion are observed by the analysis of micro Raman.(4)The structures are fixed at maximum of photoreactions after becoming gel.Our understanding of the mechanism is discussed below by thinking the photoreaction. The most realistic mechanism proposed here was that micro gels produced by photoreaction enhance the inhomogeneous light intensity because of light scattering. The kinetic constant of photoreaction in terms of light intensity shows a sigmoid function having an inflection point which is responsible for splitting the light intensity distribution into strong and weak fields.