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Published online: 20 August 2008 | doi:10.1038/nchina.2008.191

Molecular self-assembly: Sort it out!

Vicki Cleave

Introduction

© (2008) ACS

Self-sorting of monomer units to make polymers is common in biological systems; the most well-known example is the self-sorting hydrogen bonding between nucleic bases to make the biopolymers DNA and RNA. This process, however, had proven much more difficult to replicate in the lab. Feihe Huang and co-workers at Zhejiang University in Hangzhou¹ have designed a pair of monomers that can self-sort into supramolecular polymers, and demonstrate morphological control to produce drawn fibres from the polymer solution.

Huang and co-workers use two different monomer molecules, both with crown ethers attached to short, nitrogen-containing chains. The large number of oxygen atoms around the inside of the crown ether rings favours the threading of the nitrogen-containing chains through the rings, where they are held in place by numerous hydrogen bonds. The specific design of the molecules leads to polymer chains forming with alternating monomers.

The polymers only form above a critical concentration of monomers in solution, but after this point the degree of polymerization is easily controlled by varying the monomer concentrations. Different polymer morphologies, such as films or rod-like fibres (pictured), could be produced by varying the degree of polymerization, making the whole process highly adaptable for applications.

The authors of this work are from:
Department of Chemistry, Zhejiang University, Hangzhou, China.

Reference

1. Wang, F. et al. Self-sorting organization of two heteroditopic monomers to supramolecular alternating copolymers. J. Am. Chem. Soc. doi: 10.1021/ja8035465 (2008). | Article |