Research Group Nanotechnology for Life Science, Fraunhofer Institute for Applied Polymer Research, Geiselbergstrasse 69, Potsdam 14476, Germany.
Nat Chem. 2011 Mar;3(3):234-38. doi: 10.1038/nchem.964. Epub 2011 Jan 23.
Covalent bridges play a crucial role in the folding process of sequence-defined biopolymers. This feature, however, has not been recreated in synthetic polymers because, apart from some simple regular arrangements (such as block co-polymers), these macromolecules generally do not exhibit a controlled primary structure--that is, it is difficult to predetermine precisely the sequence of their monomers. Herein, we introduce a versatile strategy for preparing foldable linear polymer chains. Well-defined polymers were synthesized by the atom transfer radical polymerization of styrene. The controlled addition of discrete amounts of protected maleimide at precise times during the synthesis enabled the formation of polystyrene chains that contained positionable reactive alkyne functions. Intramolecular reactions between these functions subsequently led to the formation of different types of covalently folded polymer chains. For example, tadpole (P-shaped), pseudocyclic (Q-shaped), bicyclic (8-shaped) and knotted (α-shaped) macromolecular origamis were prepared in a relatively straightforward manner.
共价键在序列确定的生物聚合物的折叠过程中起着至关重要的作用。然而，这一特性并未在合成聚合物中重现，因为除了一些简单的规则排列（如嵌段共聚物）之外，这些大分子通常不具有受控的一级结构——也就是说，很难精确地预先确定其单体的序列。在这里，我们介绍了一种用于制备可折叠线性聚合物链的通用策略。通过苯乙烯的原子转移自由基聚合合成了结构明确的聚合物。在合成过程中精确地控制添加离散量的保护马来酰亚胺，可以形成含有定位反应性炔烃官能团的聚苯乙烯链。这些官能团之间的分子内反应随后导致形成不同类型的共价折叠聚合物链。例如，以相对简单的方式制备了蝌蚪形（P 形）、拟环形（Q 形）、双环（8 形）和纽结形（α 形）大分子折纸。
