Release behavior of pH sensitive microcapsules containing corrosion inhibitor

pH-Triggered Release of NaNO2 Corrosion Inhibitors from Novel Colophony Microcapsules in Simulated Concrete Pore Solution

“…Table shows a comparison of current works to several studies of microcapsule release. Of the alkaline conditions studied, both the microcapsules proposed by Matsuda et al have a significantly faster release rate; however, the release is comparable to the results obtained by Maia et al , This slower release rate in alkaline pH provides a longer lifetime to the microcapsule. The EE of 83% for the colophony MCs is relatively high, showing a greater value than most of the studies presented.…”

“…This study demonstrates the proposed MCs have a high encapsulation efficiency of 83.2%, similar to values observed by Matsuda et al of 79%. 56 The microencapsulated corrosion inhibitors exhibited a controlled release in alkaline environments showing a diffusion coefficient of D = 1.66 × 10 −16 m 2 /s for NO 2 − (pH = 12.6), one order of magnitude higher than for pH = 6.8. The MCs also showed oxidation in all pH solutions tested, while TGA/DSC testing showed a thermal stability range between 25 and 100 °C.…”

“…49−55 The use of pH-triggered microcapsules containing corrosion inhibitors has been investigated by Gelling et al, in which a microcapsule containing cerium nitrate was encapsulated and the release was studied for protection of aluminum alloys. 56,57 The outer shell of a pHsensitive microcapsule plays an important role in its synthesis and release performance in application. Panda et al have studied colophony applications in the pharmaceutical industry as an encapsulating agent for controlled drug release; colophony consists mainly of abietic acid amongst other resin acids and terpenes.…”

“…Microencapsulation is an emerging trend in corrosion inhibiting materials, including self-healing coatings, which are developed using microcapsules containing coating healing agents. − Microcapsules have been shown to be effective delivery systems in a variety of applications using many different stimuli including ionic, mechanical, thermal, photic, and pH. − The use of pH-triggered microcapsules containing corrosion inhibitors has been investigated by Gelling et al , in which a microcapsule containing cerium nitrate was encapsulated and the release was studied for protection of aluminum alloys. , The outer shell of a pH-sensitive microcapsule plays an important role in its synthesis and release performance in application. Panda et al have studied colophony applications in the pharmaceutical industry as an encapsulating agent for controlled drug release; colophony consists mainly of abietic acid amongst other resin acids and terpenes. , The porosity of colophony lends itself to be a practical vehicle for inhibitor release as the OH – ions present in the concrete pore solution will react with the colophony resin and the porosity will increase further, allowing the evacuation of the inhibiting agent.…”

Chitosan Derivatives and Their Application in Biomedicine

“…A pH-sensitive material can achieve the controlled release of a drug in a delivery system based on continuous changes in the pH of the gastrointestinal tract in the body. Targeted administration can be achieved according to the difference in pH between the lesion and the normal physiological state of the body [100]. pH sensitivity can be increased by introducing a sensitive acyl group in chitosan.…”