Bioinspired fabrication of macroporous calcium carbonate crystals mediated by thermoresponsive copolymers

Abstract

A new thermoresponsive copolymer, poly(N-vinylcaprolactam)-β-cyclodextrin (PNVCL–β-CD), was synthesized by click chemistry and applied in regulating the crystallization of CaCO₃. At low temperature (25 °C), the copolymers self-assembled into micelles with β-CD as the core and PNVCL as the shell. The micelles with different PNVCL chain lengths induced the formation of crystals with elongated, typical rhombohedral and surface concaved morphologies. At high temperature (50 °C), the micelles assembled into compact and regular aggregates with sizes of about 1 μm. The copolymer aggregates were encapsulated in the crystals and removed after cooling and rinsing. Porous, cheese-like crystals were obtained. This study could enrich our knowledge of biomineralization and offer a convenient scheme for synthesis of porous inorganic materials.