Oriented attachment and aggregation as a viable pathway to self-assembled organic/inorganic hybrid materials

Abstract

Organic–inorganic composite materials with tailored properties can be designed in the lab through bio-inspired approaches. In this context, we exploited the particle-based crystallisation process of calcium sulfate, a technologically important mineral, to hybridise inorganic and organic matter. We identified and synthesised an organic polymer showing strong affinity to bind to the surfaces of mineral precursors as well as intrinsic tendency to self-organise. Subsequently, polymer-coated building units were allowed to self-assemble via oriented attachment, aggregation and phase transformation, which produced ordered superstructures where the organic polymer is intercalated between the subunits and surrounds the hybrid core as a shell. This specific architecture across multiple length scales leads to unique mechanical properties, comparable to those of natural biominerals. Thus, our results devise a straightforward pathway to prepare organic–inorganic hybrid structures via bottom-up self-assembly processes innate to the crystallisation of the inorganic phase. This approach can likely be transferred to other inorganic minerals, affording next-generation materials for applications in the construction sector, biomedicine and beyond.