The effect of self-sorting and co-assembly on the mechanical properties of low molecular weight hydrogels.

Catherine Colquhoun,Louise C Serpell,Ann E Terry,Peter C Griffiths,Emily R Draper,Lin Chen,Beatrice N Cattoz,Tom O Mcdonald,Edward G B Eden,Kyle L Morris,Dave J Adams

doi:10.1039/c4nr04039b

Abstract

Self-sorting in low molecular weight hydrogels can be achieved using a pH triggered approach. We show here that this method can be used to prepare gels with different types of mechanical properties. Cooperative, disruptive or orthogonal assembled systems can be produced. Gels with interesting behaviour can be also prepared, for example self-sorted gels where delayed switch-on of gelation occurs. By careful choice of gelator, co-assembled structures can also be generated, which leads to synergistic strengthening of the mechanical properties.

Highlights

Low molecular weight gelators (LMWG) are molecules that self-assemble into one-dimensional fibres.[1,2,3] Under the right conditions, this self-assembly leads to the immobilisation of the solvent and gel formation
We showed that self-sorting occurs using a number of techniques including NMR spectroscopy, fibre X-ray diffraction and small angle neutron scattering (SANS).[31]
To exemplify self-sorted gels with additive mechanical properties, we previously demonstrated conclusively that mixtures of 1 and 2 formed self-sorted gels at a concentration of each of 5 mg mL−1.31 On addition of GdL to a mixed solution, the evolution of the rheological properties could be followed over time

Summary

Introduction

Low molecular weight gelators (LMWG) are molecules that self-assemble into one-dimensional fibres.[1,2,3] Under the right conditions, this self-assembly leads to the immobilisation of the solvent and gel formation. To exemplify self-sorted gels with additive mechanical properties, we previously demonstrated conclusively that mixtures of 1 and 2 formed self-sorted gels at a concentration of each of 5 mg mL−1.31 On addition of GdL to a mixed solution, the evolution of the rheological properties could be followed over time.

Results

Conclusion