INTERPHASE REINFORCEMENT FOR STRONGER AND TOUGHER COMPOSITES

Most modern synthetic materials, such as inherently stiff ceramics, require both high yield strength and high toughness, i. e. resistance to cracking. This is usually not easy to achieve, since these qualities are typically mutually exclusive – a stronger and stiffer material is more likely to fail in a brittle manner. One of the main pathways of composite material failure occurs at the interfaces and/or interphases between the composites’ constituents; therefore, tuning of the interphase adhesion may lead to tougher materials without compromising strength. This pathway is especially prevalent in laminated composites with stiff ceramic layers and soft polymer interlayers.

We used evaporation-driven self-assembly (EDSA) to deposit a thin network of multi-wall carbon nanotubes on ceramic surfaces, to serve as interphasial reinforcement. We prepared ceramic-polymer-ceramic sandwich composites with such reinforced interphases, and they exhibited significant improvements in both yield strength and toughness. The volume fraction of MWNT used in this work was extremely low, making it a most effective reinforcement technique.