Synthesizing of smart micro/ nanocapsules containing corrosion inhibitors: A study of the parameters affecting on the capsule size

In this research, micro- and nanocapsules of melamine-formaldehyde-pentaerythritol tetrakis successfully synthesized. These micro/nanocapsules are pH-sensitive, the capsule wall degrades in the alkaline environment and releases its core content. The purpose of this paper is to investigate the two parameters, the surface tension of the capsule core material and the effect of shear stress on the encapsulation process as parameters affecting the size of the capsules. The size, morphology, and behavior of the capsules were investigated by scanning electron microscopy (SEM). By using Measurement software, the size of the capsules was obtained. Then the distribution and histogram were plotted with using SPSS software. The size of the microcapsules was 5.5 μm and the nanocapsules in three different synthetic conditions were: 225, 312, 250 nm. Thermogravimetric analysis was also used to evaluate and compare the core to shell ratio of the micro- and nanocapsules. The results determined that by changing the size of the capsules, the core to shell ratio, the optimum conditions to achieve smooth morphology and release behavior changed.