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Peer reviewed: True, To facilitate the ongoing transition towards carbon neutrality, the use of renewable materials for additive manufacturing has become increasingly important. Here we report for the first time the fabrication of microcapsules from biobased acrylate shells using microfluidics. To select the shell, a wide range of biobased acrylates disclosed in the literature was considered according to their tensile strength, ductile transition temperature and global availability. Once acrylate epoxidised soybean oil (AESO) was selected, its viscosity was adjusted to valuables suitable for the microfluidic device using two different diluting agents. Double emulsions were successfully produced using microfluidics, followed by photopolymerisation of the shell and characterisa-tion of the capsules. Microcapsules containing AESO and isobornyl acrylate (IBOA) were pro-duced with an outer diameter ~ 490 μm, shell thickness ranging between 36 and 67 μm, and production rates around 2.4 g/h. The mechanical properties of the shell were characterised as tensile strength of 29.2 ± 7.7 MPa, Young’s modulus of 1.7±0.4 GPa and the ductile transition temperature was estimated as 42°C. To investigate physical triggering, microcapsules produced with a size of 481 ± 4 μm and with a measured shell thickness around 6 μm were embedded in the cementitious matrix. The triggered shells were observed with scanning electron microscopy (SEM) and the uniform distribution of the capsules in cement paste was confirmed using X-ray computed tomography (XCT). These advances can facilitate the wide application of biobased resins for the fabrication of microcapsules for self-healing in cementitious materials., Aspects of this work reported here was carried out as part of an MEng research project by the second author [35]. The authors also acknowledge the financial support provided to the first au-thor from the UKRI-EPSRC, grant number EP/P02081X/1 (Resilient Materials 4 Life, RM4L).

In spite of the well-established design and construction approaches of slag–cement–bentonite slurry walls, the materials deteriorate inevitably in contaminated land. The development of effective materials which are sustainable, resilient and self-healing over the lifetime of slurry walls becomes essential. This study, for the first time, adopts a styrene–ethylene/butylene–styrene (SEBS) polymer to modify slag–cement–bentonite materials to enhance mechanical and self-healing performance. The results show that the increase in SEBS dosage results in significantly increased strain at failure, indicating the enhanced ductility thanks to the modification by the deformable polymer. The increased ductility is beneficial as the slurry wall could deform to a greater extent without cracks. After the permeation of liquid paraffin, the SEBS exposed on the crack surface swells and seals the crack, with the post-healing permeability only slightly higher than the undamaged values, which exhibits good self-healing performance. Scanning electron microscopy and micro-computed tomography analyses innovatively reveal the good bonding and homogeneous distribution of SEBS in slag–cement–bentonite. SEBS acts as a binder to protect the slag–cement–bentonite sample from disintegration, and the swollen SEBS particles effectively seal and heal the cracks. These results demonstrate that the SEBS-modified slag–cement–bentonite could provide slurry walls with resilient mechanical properties and enhanced self-healing performance.