Spatially Controlled Distribution of Copolymer Nanoparticles within Calcite Crystals Enabled by Engineering Surface Chemistry

The incorporation of nanoparticles into a growing crystal is rather counterintuitive due to interfacial incompatibility between the guest nanoparticles and the host crystals. Furthermore, achieving precise control over the spatial distribution of these nanoparticles within the host crystals presents a significant challenge. In this study, we judiciously synthesize three types of well-defined copolymer nanoparticles, each with different steric stabilizers─poly(methacrylic acid), poly(3-sulfopropyl methacrylate potassium), or poly(methacrylic acid-stat-3-sulfopropyl methacrylate potassium)─via polymerization-induced self-assembly. Such nanoparticles are then used as model additives in the crystallization of calcite under varying initial calcium ion concentrations. Remarkably, systematic investigations reveal that the spatial distribution of these copolymer nanoparticles within a calcite single crystal is governed by their surface chemistry and the initial calcium ion concentration. The underlying mechanisms are proposed to rationalize these intriguing phenomena of spatially tunable nanoparticle incorporation. This work provides important “design rules” for rationally regulating the spatial incorporation of guest nanoparticles into host crystals, thereby offering a straightforward and effective approach for making crystalline nanocomposites with controllable internal compositions and structures.