As highlighted in recent BBC News broadcasts, the Department of Engineering’s Geotechnical and Environmental Research Group is developing microcapsules containing “healing” agents – such as minerals, epoxy or polyurethane – which can be added to building materials to allow self-repair of small cracks which develop over time (Lívia Ribeiro de Souza and Abir Al-Tabbaa. Construction and Building Materials, 2018, 184, 713-722.)
“Many composite building materials used in the construction industry – such as concrete – suffer fatigue over time, developing small cracks,” said Dr. Livia Ribeiro de Souza, a postdoctoral researcher in the group. “We are hoping to overcome this problem by adding microcapsules filled with ‘healing’ agents to the concrete before it is used. The idea is that, as cracks begin to form, they rupture the microcapsules, releasing their payload and stabilizing the material.
“This approach requires the formation and functionalization of double emulsion microcapsules, which we have been producing with the help of microfluidics. We have been using a Dolomite Microfluidics system since 2014, and find that microfluidics offers much better control of particle size and composition than traditional emulsification polymerization techniques, simplifying the investigation and optimization of particle properties.”
The Dolomite system has enabled the researchers to create functionalized microcapsules that bind more strongly to the cement matrix, while also having thinner shell walls and higher core retention, improving their self-healing properties.