Synthesis of Calcium Nitrate Self-Healing Microcapsules Using Aerosol OT-Hexane Solution for Cementitious Materials

Abstract

Calcium nitrate synthesis of in urea-formaldehyde shell has recently been used to produce self-healing microcapsules for construction applications. The original synthesis was based on water-in-oil emulsion with sulfonic acid as fundamental ingredient of the oil (continuous) phase. It has been modified herein by changing the composition of the continuous (oil) phase by mixing anionic surfactant, Aerosol OT (AOT) with hexane to prepare the solution while keeping the aqueous phase unchanged. The submicron refined calcium nitrate microcapsules. In order to characterize the microcapsules encapsulated using the aforementioned, procedure, a Scanning Electron Microscopy (SEM) was utilized. The obtained microcapsules had satisfactory diameter and shell thickness. To assess the effect of the prepared microcapsules on the compressive and flexural strengths, mortar mixes containing 75% microcapsules (by weight of cement), as an introductory dosage, were made. It has been demonstrated that incorporating the self-healing microcapsules prepared using the procedure suggested in this study did not cause significant reductions in the mortar samples' strengths. Hence, the encapsulation methodology presented here may be utilized to investigate their self-healing efficiency in cementitious materials.