Synthesis and studies on gelation ability of phenol based maleate amphiphile and its application in nutraceutical release

Abstract

In the search for a low molecular weight organo gelator, sodium-4-oxo-4-((11-phenoxyundecyl)oxy)but-2-enoate (PUDMS) was designed and synthesized using phenol, 11-bromoundecanol, and maleic anhydride as starting materials. The maleate based amphiphile entrap hydrocarbon solvents like cyclohexane, hexane, and heptane in the presence of 25μL water, interestingly in pure solvents no gelation was observed. Among the hydrocarbon solvents, cyclohexane shows excellent gelation with lowest critical gelation concentration (0.44mg/mL) value with higher gelation number (8005) in an optimal water volume of 25μL. The organogels were characterized by various conventional techniques such as rheology, DSC, FE-SEM, and XRD. The dynamic mechanical strength is independent of the angular frequency ranging between 0.1Hz to 12Hz irrespective of the organic solvent used, though cyclohexane showed little higher magnitude in the storage modulus (G') value. The microstructure observed by the FE-SEM study suggested PUDMS has emulsified morphology for cyclohexane and hexane solvent where as sheet like structure observed for heptane. Further, the bilayer thickness for the gel network structure was calculated from XRD studies. The pH-induced release of vitamin B12 from the vitamin B12-loaded PUDMS organogel, showing potential application in pH-triggered nutraceutical release.