Structural Transition of Inorganic Silica–Carbonate Composites Towards Curved Lifelike Morphologies

Abstract

The self-assembly of alkaline earth carbonates in the presence of silica at high pH leads to a unique class of composite materials displaying a broad variety of self-assembled superstructures with complex morphologies. A detailed understanding of the formation process of these purely inorganic architectures is crucial for their implications in the context of primitive life detection as well as for their use in the synthesis of advanced biomimetic materials. Recently, great efforts have been made to gain insight into the molecular mechanisms driving self-assembly in these systems, resulting in a consistent model for morphogenesis at ambient conditions. In the present work, we build on this knowledge and investigate the influence of temperature, supersaturation, and an added multivalent cation as parameters by which the shape of the forming superstructures can be controlled. In particular, we focus on trumpet-and coral-like structures which quantitatively replace the well-characterised sheets and worm-like braids at elevated temperature and in the presence of additional ions, respectively. The observed morphological changes are discussed in light of the recently proposed formation mechanism with the aim to ultimately understand and control the major physicochemical factors governing the self-assembly process.Minerals 2018, 8, 75 2 of 12 similar structures can also be obtained with other carbonates, including orthorhombic analogues like strontianite (SrCO 3 ) [8,9] or aragonite (CaCO 3 ) [10][11][12].Minerals 2017, 7, 75 2 of 11 evidence that similar structures can also be obtained with other carbonates, including orthorhombic analogues like strontianite (SrCO3) [8,9] or aragonite (CaCO3) [10][11][12].

Influence of Nucleic Acids on the Synthesis of Crystalline Ca(II), Ba(II), and Sr(II) Silica–Carbonate Biomorphs: Implications for the Chemical Origin of Life on Primitive Earth

“…37 The morphology, observed through SEM, of the silica-strontium carbonates formed at 50 °C revealed that the control sample depicts structures of leaves and flowers (Figure 7B), which is the typical structure reported by other authors for these compounds. 38,39 The silica-strontium carbonates synthesized with gDNA showed a spherical morphology, formed by crystals in the form of perfectly ordered needles (Figure 7B). The samples obtained in the presence of pDNA formed structures of hollow stems with crystals perfectly ordered in their ends (Figure 7B).…”

The Influence of Silicateins on the Shape and Crystalline Habit of Silica Carbonate Biomorphs of Alkaline Earth Metals (Ca, Ba, Sr)

“…In the past fifty years, several techniques have been developed for the synthesis and characterization of these biomorphs [8]. Several studies published elsewhere have evaluated the impact of physical parameters including temperature [8], electric fields [9], UV light [10], pH, CO 2 content and growth in solution or gels on the formation of biomorphs [11][12][13][14]. In addition, the influence of cationic additives [15] and biomolecules such as nucleic acids and amino acids in the synthesis of these biomorphs has also been recently reviewed [16,17].…”

False biosignatures on Mars: anticipating ambiguity

“…Under some conditions, more atypical morphologiessuch as flower-like forms, 'trumpets', 'corals', 'moths', 'snails' or 'mushrooms' (Fig. 2h)can also be found (Opel et al 2018;Rouillard et al 2018).…”