Phase behavior of multi-stimuli-responsive ionic liquids-based micro-emulsion and its application in nano silica synthesis and curcumin encapsulation

Abstract

The enrichment and separation of trace compounds, as well as the preparation of nanomaterials, are all greatly facilitated by responsive micro-emulsion. A multi stimuli-responsive ionic liquids-based micro-emulsion system was established with alkyl-N-Tropine (trans) P-methoxycinnamate ([CnTr][PMCA], TILS) as a surfactant. The factors affecting the phase behavior of micro-emulsion, such as the structure of the TILS, cosurfactant, oil, temperature, pH, and salinity, were investigated by multiple research methods. Five zones were identified inside the micro-emulsion phase region as O/W, B.C., liquid crystal (L.C.), L.C.+B.C., and W/O. The TILS-based micro-emulsion displayed high stability at measured temperatures. High salinity contributed to a higher water solubilization capacity of the micro-emulsion. For the potential applications of the micro-emulsion, with sizes ranging from 20 to 70 nm, nanoscale silica particles showed persistent stability. High levels of drug loading rate (about 8.6 mg·g−1) and encapsulation efficiency (about 99%) of the micro-emulsion loaded with curcumin were attained.