A rechargeable self-healing safety fuel gel

Abstract

The stimuli responsive assembly of small molecules that can modulate the physical properties of a supramolecular system may have potential as futuristic materials. The dimethyl dipicolinate in alcohol, when combined with 3 equiv. of potassium hydroxide and water, aggregates to a strong self-healing transparent gel. The instant gelation is highly selective towards potassium hydroxide and does not need any heating–cooling or sonication. The gelation is also selective for solvent systems such as 9 : 1 methanol–water or ethanol–water. The rheological stepstrain measurements under varying strain at room temperature show that the gel is thixotropic in nature. The gel can be shaped like any free-standing objects due to its high mechanical strength. The gel exhibits remarkable self-healing properties when damaged and diffusion of methyl orange through the gel suggests the dynamic nature of the gel. We found that the non-explosive gel can be packaged in a polyethylene tube and used as a safe fuel for indoor and outdoor heating without any special stove or burner. The gelator retains strong memory even after burning which makes it rechargeable up to four times by the addition of (9 : 1) methanol–water.