聚羟基丁酸酯共聚物超薄膜中向日葵晶形成的原子力显微镜观察

低维数下的高分子(如在二维薄膜或一维管道及孔洞中)的各种行为由于更加触及高分子的动力学、热力学本质而逐渐成为高分子科学研究的热点之一．实验表明，薄膜中聚合物的玻璃化转变温度、结晶动力学及形貌等与本体有很大的偏离．我们先前的研究结果表明，在基板的作用下，共混物薄膜的相形态会发生逆转；

AFM Observation of Sunflower-like Crystalline Morphology Formed in Ultra-thin Film of Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)

Poly(3-hydroxybutyrate-co-10%3-hydroxyhexanoate)(PHBHHx) thin films were prepared by means of spin-coating PHBHHx/chloroform solutions on the silicon substrate. The crystalline morphologies of PHBHHx thin films were observed by atomic force microscopy(AFM) at room temperature. A novel crystalline morphology, that is like sunflower was found when the film is very thin and named as sunflower-like crystalline morphology. Compared with usual PHBHHx spherulites, there are obvious differences in aspects of nucleation, crystal growth process and crystalline morphology for the sunflowers. The PHBHHx/chloroform solution properties and the substrate have great effects on the formation of the sunflower. A circular boundary that may result from a liquid-liquid phase separation in PHBHHx solution first formed in the thin film during the spin-coating process, then it induced the formation of the sunflowers.