Polymer deaggregation and assembly controlled by a double cavity cucurbituril

Abstract

A supramolecular polymer was prepared from a mixture of poly(diallyldimethylammonium chloride) (1) and bis-ns-CB[10]. The repeat units of the polymer chain are capable of binding inside each of the two cavity domains of bis-ns-CB[10]. The bis-ns-CB[10] molecular containers complex the sides of the polymer chain – which we term a cupping interaction – thereby promoting the association of individual polymer strands to form 1 _n √bis-ns-CB[10] _m , which results in an extension of the length of the polymer. The effect of bis-ns-CB[10] on the physical properties of the polymer was investigated using viscometry in dilute aqueous solution. A decrease in η_rel was observed upon increasing the concentrations of bis-ns-CB[10] to a solution of 1. Atomic force microscopy and diffusion-ordered spectroscopy were performed to probe the mode of interaction between polymer 1 and bis-ns-CB[10]. Collectively, the data support the two roles for bis-ns-CB[10]: (1) as a deaggregation agent at lower concentrations and (2) as a cupping agent that non-covalently links individual polymer strands at higher concentrations resulting in overall extension of the polymer.

Keywords:

• supramolecular polymer
• cucurbituril
• viscometry

Acknowledgements

We would like to thank the members of the Scherman group for instructive conversations. We thank the National Science Foundation (CHE-0615049 and CHE-0829337 to LI), the Department of Education (P200A060238-07, GAANN fellowship to RN) and the UK Engineering and Physical Sciences Research Council (EP/F035535) and the Walters–Kundert Trust (OAS) for financial support.

Notes

^†Dedicated to the memory of Prof. Dmitry Rudkevich