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Abstract：
Block copolymers are a class of materials that are particularly interesting with respect to their capability to self-assemble in ordered structures. In this context, the coupling between environment and dynamics is particularly relevant given that movements at the molecular level influence various properties of macromolecules. Mixing the polymer with a second macromolecule appears to be an easy method for studying these relationships. In this work, we studied blends of poly(methyl methacrylate) (PMMA) and a block copolymer composed of PMMA as the first block and poly(3-methyl-4-[6-(methylacryloyloxy)-hexyloxy]-4\'-pentyloxy azobenzene) as the second block. The relaxational properties of these blends were investigated via electron spin resonance (ESR) spectroscopy, which is sensitive to nanometric length scales. The results of the investigations on the blends were related to the dynamic behavior of the copolymers. At the nanoscale, the study revealed the presence of heterogeneities, with slow and fast dynamics available for molecular reorientation, which are further modulated by the ability of the block copolymers to form supramolecular structures. For blends, the heterogeneities at the nanoscale were still detected. However, it was observed that the presence of the PMMA as a major component of the blends modified their dynamic behavior.
摘要：
嵌段共聚物是一类在有序结构中自组装的能力方面特别令人感兴趣的材料。在这种情况下，考虑到分子水平的运动会影响大分子的各种性质，环境与动力学之间的耦合尤其重要。将聚合物与第二大分子混合似乎是研究这些关系的简单方法。在这项工作中,我们研究了聚（甲基丙烯酸甲酯）（PMMA）和由PMMA作为第一嵌段和聚（3-甲基-4-[6-（甲基丙烯酰氧基）-己氧基]-4'-戊氧基偶氮苯）作为第二嵌段组成的嵌段共聚物的共混物。通过电子自旋共振（ESR）光谱研究了这些共混物的弛豫特性，对纳米长度尺度敏感。对共混物的研究结果与共聚物的动态行为有关。在纳米级，这项研究揭示了异质性的存在，具有可用于分子重新定向的缓慢和快速动力学，其进一步通过嵌段共聚物形成超分子结构的能力来调节。对于混合物，仍然检测到纳米级的异质性。然而,观察到PMMA作为共混物的主要组分的存在改变了其动态行为。
