Dissolution, regeneration and ion-gel formation of agarose in room-temperature ionic liquids

Abstract

The suitability of several ionic liquids, containing imidazolium or pyridinium cations with different alkyl chains and anions ranging from small hydrogen-bond acceptors to those of a large and non-coordinating nature, has been tested for solubilization of a widely used biopolymer, agarose. The solubility of agarose was found to depend on both the nature of anion and amphiphilicity of the cation. Dissolved agarose was regenerated using methanol, and ionic liquids were recovered and recycled for different experiments. Regenerated agarose largely maintained the features of native agarose in terms of molecular weight, polydispersity, thermal stability and crystallinity but varied slightly in conformation preferences. Subsequently, agarose-based highly conducting soft ion-gels having small thermal hysteresis were prepared and characterized. Such ion-gels have possible applications as electrochemical devices.