Wang Hongfang, Wu Cong, Xia Guangmei, Ma Zhi, Mo Guang, Song Rui
College of Chemistry and Chemical Engineering, University of Chinese Academy of Sciences, Beijing 100049, China.
Soft Matter. 2015 Mar 7;11(9):1778-87. doi: 10.1039/c4sm02581d.
In this paper, we have systematically investigated the aggregation behavior, confined crystallization and controlled growth of a novel polyolefin analogue-containing block copolymers (BCPs), i.e., polymethylene-b-poly(acrylic acid) diblock copolymers (PM-b-PAA). On cooling from a homogenous DMF solution at 80 °C, PM-b-PAA was found to crystallize and aggregate with well-defined disk-like micelles. The aggregate behavior and in-plane morphology of PM-b-PAA could be easily controlled by modifying the block ratio, solution pH and solvent composition (DMF-water), by manipulating the crystallization of PM block and the stretching degree of solvated PAA corona. Further investigation of the crystalline feature of PM-b-PAA indicated that the crystallization of PM was retarded by tethered amorphous PAA segments. The crystalline micelle could construct a nano-confined environment with PM folding as the core into a thickness of the mono-layered polyethylene. Finally, when cultured in dilute DMF solution at 50 °C, the initial crystalline micelles, being as self-seeds, could follow a living growth mechanism and develop into single crystals, with well-defined lozenge-shaped morphology.
在本文中，我们系统地研究了一种新型含聚烯烃类似物的嵌段共聚物（BCP），即聚亚甲基-b-聚丙烯酸二嵌段共聚物（PM-b-PAA）的聚集行为、受限结晶和可控生长。从80℃的均相N,N-二甲基甲酰胺（DMF）溶液冷却时，发现PM-b-PAA会结晶并聚集成具有明确盘状胶束的聚集体。通过改变嵌段比、溶液pH值和溶剂组成（DMF-水），通过控制PM嵌段的结晶和溶剂化PAA冠层的拉伸程度，可以轻松控制PM-b-PAA的聚集行为和面内形态。对PM-b-PAA结晶特征的进一步研究表明，连接的无定形PAA链段会阻碍PM的结晶。结晶胶束可以构建一个以PM折叠为核心的纳米受限环境，形成单层聚乙烯的厚度。最后，当在50℃的稀DMF溶液中培养时，初始结晶胶束作为自种子，可以遵循活性生长机制并发展成具有明确菱形形态的单晶。
