Extended Data Figure 4: Gluing gels of different stiffness or chemical nature.
From: Nanoparticle solutions as adhesives for gels and biological tissues
a, Force–displacement curve for an assembly made of soft PDMA S0.1 and rigid PDMA S1.5 (red triangles) gels glued by TM-50 solution. For comparison the results obtained under identical conditions for the symmetric PDMA S0.1/S0 assembly are plotted (blue circles). Lap-joint dimensions were l = 10 mm, w = 5 mm and h = 2 mm. 15 μl of TM-50 solution was spread to make the junction. b, Glued at their preparation state, both PDMA S0.1 and PDMA S1.5 gels initially had the same size (diameter of about 10 mm). The picture shows gels after 5 h of swelling in deionized water. The highly crosslinked PDMA S1.5 gel (top piece) is less swollen than the PDMA S0.1 gel (bottom piece). Interfacial stresses induced by heterogeneous overswelling considerably exceed the shear stresses applied in the mechanical lap-shear test of a and lead to interfacial failure during immersion and overswelling in water. De-bonding was slow. c, Lap-shear force–displacement trace for the gelatine and S0.1 PDMA gel assembly (green stars) glued by spreading TM-50 silica solution. The failure occurred outside the lap joint and the fatal crack propagated in tension mode.
