Synthesis and characterization of versatile low molecular weight gelators towards functional metal-organic soft-materials

Abstract

Over the past few decades, enormous research interest has been directed towards the development of functional gel materials due to their widespread applications in biomedicine, optoelectronics, cosmetics, and in food industry.1 Gels are soft materials which are easily recognized by ?inversion test? method, which means if a pot of gel is turned upside down it remains stable under gravitational force.2 Daily-life examples of gel include shower gel, shampoo, toothpaste, hair gel, soft contact lenses, etc. which are basically multi-component gels. In general, gels are viscoelastic solid-like materials which comprise of two coexisting phases; a large amount of liquid phase and a solid network which immobilises the flow of solvents. Depending upon the nature of solid phase gels are broadly divided into two categories: i) polymeric gels and ii) supramolecular gels (Chart 1). Among these two types, polymeric gels have been known for centuries. They consist of cross-linked polymer networks and the interstitial spaces of the network are filled with fluid. Polymer gels have ability to undergo substantial swelling and collapsing depending upon the environment.