Photothermal Conversion-Enabled Temperature Modulation for the Growth of Complex Polymorphic Architectures of Calcium Carbonate

As a highly efficient and eco-friendly heat generation approach, the photothermal conversion process has been applied to many important areas such as evaporation, desalination, and medical treatments. In this study, we explored the application of photothermal conversion in the synthesis of complex polymorphic calcium carbonate (CaCO₃) structures. We chose CaCO₃ as our model system for this study due to the significant role in biomineralization. Furthermore, the temperature-dependent growth property of different CaCO₃ polymorphic phases (calcite, aragonite and vaterite) also provides potential for this study exploration. By leveraging quick temperature change enabled by photothermal conversion, we achieved the stepwise temperature modulation between “cold” and “hot” and successfully fabricated architectures composed of multiple polymorphic phases, specifically aragonite@calcite, calcite@aragonite, and calcite@aragonite@calcite. The coexistence of these distinct polymorphic phases within the same architecture was confirmed through confocal Raman micro-spectroscopy analysis. Furthermore, substrate modification was achieved <i>via</i> patterned self-assembled monolayers using soft lithography, which allowed the growth of arrays of complex polymorphic CaCO₃ structures on the surface. This study provides an efficient and promising methodology for thermally controlling of the growth of materials with desired multi-phases and multi-functionalities. The ability to manipulate the phase composition and spatial arrangement of calcite carbonate on a single substrate provides new opportunities for developing multifunctional materials with both tailored properties and at designated positions. This study may potentially impact various fields, including biomineralization, photonic materials, and industrial fabrication processes.