Fundamental Study of Polymer Organization at the Interfaces by the Fusion of Organic Chemistry and Physical Chemistry

从离子两亲性二嵌段共聚物的合成到纳米结构分析，系统地研究了离子两亲性二嵌段共聚物的分子性质和自组装，如在水中的胶束和在空气/水界面的单层。出乎意料的是，离子两亲嵌段共聚物表现出“非表面活性”，但在溶液中形成胶束。由于这种现象不符合表面和界面科学的常识，因此可以认为这种聚合物是一种新型物质。通过对不同链长和长度比的嵌段共聚物的研究，发现非表面活性的来源可归因于空气/水界面的像电荷效应，并定量地阐明了非表面活性的要求。非表面活性是通过三个因素，聚合性，离子性和疏水性的精确平衡来实现的。聚合物胶束在水中表现出极高的抗盐韧性。0.5M NaCl下未形成聚集体。在链长和盐浓度的作用下，还观察到球状和棒状胶束之间更多的转变。利用x射线和中子反射率技术系统地研究了它们在水面上的聚合物单层的纳米结构。单层结构不是简单的疏水和亲水刷层双层结构，而是三层结构，中间有“地毯”层。地毯层为致密亲水性层，其厚度在15Å处几乎不变。可以估算出两层和三层结构过渡时的临界电刷密度。同时，发现盐加入引起纳米结构变化的临界盐浓度约为10^<-1>M盐。综上所述，离子两亲性二嵌段共聚物这一“新物质”的性质和自组装行为可以通过两亲性聚合物的进动合成和纳米结构的散射和反射率分析技术的融合来阐明。少

Molecular properties and self-assemblies, such as micelle in water and monolayer at the air/water interface, of ionic amphiphilic diblock copolymers were systematically investigated from synthesis to nanostructure analysis.Unexpectedly, the ionic amphiphilic block copolymers shows "non-surface activity" but forms micelles in solution. Since this phenomenon is out of commonsense of surface and interface science, this polymer can be regarded as a novel substance. By investigation with block copolymer with various chain length and length ratios, the origin of the non-surface activity could be attributed to the image charge effect at the air/water interface, and the requirements to be non-surface active were quantitatively clarified. The non-surface activity is achieved by the accurate balance of three factors, polymerity, ionicity, and hydrophobicity.The polymer micelle in water shows extremely high toughness against salt addition. No aggregates were formed up to 0.5M NaCl. The structure … More transition between spherical and rod-like micelles were also observed as a function of chain length and salt concentration.The nanostructure of their polymer monolayer on the water surface was systematically investigated by X-ray and neutron reflectivity techniques. The monolayer structure is not a simple double layer of hydrophobic and hydrophilic brush layers, but is triple layer with "carpet" layer between them. The carpet layer is dense hydrophilic layer, whose thickness is almost constant at 15Å. The critical brush density for the transition between double and triple layer structures could be estimated. Also, the critical salt concentration, where nanostructure change occurs by salt addition, was found to be in the order of 10^<-1>M salt.In conclusion, the properties and self-assembling behavior of "novel substance", ionic amphiphilic diblock copolymer, could be clarified by the fusion of high techniques for precession synthesis of amphiphilic polymers and for nanostructure analysis with scattering and reflectivity. Less