| 초록 |
If cracks can be easily detected in the initial stage, this could help users heal or replace the cracked materials before their complete destruction. The object of this study is to develop a crack sensor by which microcracks are detected as the capsules are broken upon microcrak formation and propagation. We have performed microencapsulation of a fluorescent liquid using poly(urea-formaldehyde) as a shell material. The effect of agitation rate, core/shell mass ratio, surfactant concentration, and reaction time on capsule characteristics such as size, shell thickness, and surface morphology were studied. The formation of microcapsules was confirmed by FTIR and TGA, and capsule characteristics were studied by FE-SEM. It was observed that the crack planes showed strong fluorescence while the uncracked surfaces did not. Fluorescence microscopic images of microcracks in the polymer coatings containing the microcapsules were obtained by excitation with 330-385 nm UV light. |
