Building materials delamination

One of main thrusts in organic-perovskite hybrids has been in the preparation of stable delaminated perovskite sols as the building blocks of nanocomposite materials. A well-known process for exfoliation is to weaken the attractive interaction of the layers through intercalation of bulky organic components. A representative example is exfoliation of bismuth-based cuprate superconductors (Figure 14.12). °3... 

Typically, with lightly cross-linked materials the shear failure is cohesive. This is also the case for physically cross-linked materials such as styrenic block copolymers, particularly at elevated temperatures. However, as the cohesive strength of the PSA increases and/or as the resistance to peel adhesion falls, the mode of failure will tend to switch to adhesive, normally initiated as a delamination from the substrate at the corners of the tape. As the delamination grows and the stress builds, failure can be rapid and catastrophic with the debond crack traveling interfacially, alternately along the substrate and the backing interface. 

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