Design, Structure, and Applications of 1-Dodecyl-3-(tolyl) Urea Low Molecular Weight Organogelators

This article describes the discovery, characterization and application of a small family of urea-based low molecular weight organogelators (LMWOs), namely the para-, meta- and ortho-1-dodecyl-3-(tolyl) ureas. All three LMWOs were tested for their ability to gel both polar and non-polar solvents and their properties were compared, with 1-dodecyl-3-(o-tolyl) urea proving the most versatile. 1-dodecyl-3-(o-tolyl) urea successfully gelled 1-octadecene, dimethylsulfoxide, petroleum ether, cyclohexane and toluene, with the latter gelling at just 0.8 wt.% of LMWO, making it a supergelator. The ability to gel both polar and non-polar solvents is an interesting and unusual property exhibited by few LMWO molecules, and as such, the applications for this molecule move beyond typical applications such as oil-spill remediation, into the biomedical and cosmetics sphere. Gels were characterized using rheology, small-angle neutron scattering (SANS), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). Applications of 1-dodecyl-3-(o-tolyl) urea gels of dimethyl sulfoxide demonstrated in this study include in vitro release into an aqueous medium and bioimaging agent delivery.