Thermal assisted self-organization of calcium carbonate

Mimicking nature to develop halide perovskite semiconductors from proteins and metal carbonates

Halide perovskite (HPs) nanostructures have recently gained extensive worldwide attentions because of their remarkable optoelectronic properties and fast developments. However, intrinsic instability against environmental factors-i.e., temperature, humidity, illumination, and oxygen-restricted their real-life applications. HPs are typically synthesized as colloids by employing organic solvents and ligands. Consequently, the precise control and tuning of complex 3D perovskite morphologies are challenging and have hardly been achieved by conventional fabrication methods. Here, we combine the benefits of self-assembly of biomolecules and an ion exchange reaction (IER) approach to customize HPs spatial shapes and composition. Initially, we apply a biomineralization approach, using biological templates (such as biopolymers, proteins, or protein assemblies), modulating the morphology of MCO3 (M = Ca2+, Ba2+) nano/microstructures. We then show that the morphology of the materials can be maintained throughout an IER process to form surface HPs with a wide variety of morphologies. The fabricated core-shell structures of metal carbonates and HPs introduce nano/microcomposites that can be sculpted into a wide diversity of 3D architectures suitable for various potential applications such as sensors, detectors, catalysis, etc. As a prototype, we fabricate disposable humidity sensors with an 11-95% detection range by casting the formed bio-templated nano/micro-composites on paper substrate.

Patterns Lead the Way to Far-from-Equilibrium Materials

The universe is a complex fabric of repeating patterns that unfold their beauty in system-specific diversity. The periodic table, crystallography, and the genetic code are classic examples that illustrate how even a small number of rules generate a vast range of shapes and structures. Today, we are on the brink of an AI-driven revolution that will reveal an unprecedented number of novel patterns, many of which will escape human intuition and expertise. We suggest that in the second half of the 21st century, the challenge for Physical Chemistry will be to guide and interpret these advances in the broader context of physical sciences and materials-related engineering. If we succeed in this role, Physical Chemistry will be able to extend to new horizons. In this article, we will discuss examples that strike us as particularly promising, specifically the discovery of high-entropy and far-from-equilibrium materials as well as applications to origins-of-life research and the search for life on other planets.

Computational assessment of the potential of cross-catalytic coprecipitating systems for the bottom-up design of nanocomposites

The production of nanocomposites is often economically and environmentally costly. Silica-witherite biomorphs, known for producing a wealth of life-like shapes, are nanocomposites entirely formed through self-organization processes. Behind these precipitates are two precipitation reactions that catalyze each other. Using a simple computational approach, we show here that this type of chemical system - defined here as Cross-Catalytic Coprecipitating Systems (CCCSs) - is of great interest to material design. Provided that cross-catalytic effects are sufficient to overcome the precipitation thresholds for each phase, all CCCSs can be expected to self-organize into nanocomposite materials through a one-pot, one-step synthesis protocol. Symmetry-breaking events generating various complex, ordered textures are predicted in CCCSs involving crystalline phases. While high levels of stochasticity lead to a loss of ordering, coprecipitation is found to be robust to diffusion or advection in the solution. This model shows that a couple of chemical reactions can generate a range of complex textures - with possibly distinct physical/chemical properties. Cross-catalytic coprecipitating systems consequently represent a promising avenue for producing nanocomposites with complex textures at reduced economic and environmental costs.

Light-driven nucleation, growth, and patterning of biorelevant crystals using resonant near-infrared laser heating

Spatiotemporal control over crystal nucleation and growth is of fundamental interest for understanding how organisms assemble high-performance biominerals, and holds relevance for manufacturing of functional materials. Many methods have been developed towards static or global control, however gaining simultaneously dynamic and local control over crystallization remains challenging. Here, we show spatiotemporal control over crystallization of retrograde (inverse) soluble compounds induced by locally heating water using near-infrared (NIR) laser light. We modulate the NIR light intensity to start, steer, and stop crystallization of calcium carbonate and laser-write with micrometer precision. Tailoring the crystallization conditions overcomes the inherently stochastic crystallization behavior and enables positioning single crystals of vaterite, calcite, and aragonite. We demonstrate straightforward extension of these principles toward other biorelevant compounds by patterning barium-, strontium-, and calcium carbonate, as well as strontium sulfate and calcium phosphate. Since many important compounds exhibit retrograde solubility behavior, NIR-induced heating may enable light-controlled crystallization with precise spatiotemporal control.

Nonclassical Crystallization Causes Dendritic and Band-Like Microscale Patterns in Inorganic Precipitates

The self-organization of complex solids can create patterns extending hierarchically from the atomic to the macroscopic scale. A frequently studied model is the chemical garden system which consists of life-like precipitate shapes. In this study, we examine the thin walls of chemical gardens using microfluidic devices that yield linear Ni(OH)2 precipitate membranes. We observe distinct light-scattering patterns within the compositionally pure membranes, including disorganized spots, dendrites, and parallel bands. The bands are tilted with respect to the membrane axis and their spacing (20-100 μm) increases with increasing flow rates. Scanning electron microscopy reveals that the bands consist of submicron particles embedded in a denser material and these particles are also found in the reactant stream. We propose that dendrites and bands arise from the attachment of solution-borne nanoparticles. The bands are generated by particle-aggregation zones moving upstream along the slowly advancing membrane surface. The speed of the aggregation zones is proportional to the band distance and defines the system's dispersion relation. This speed-wavelength dependence and the flow-opposing motion of the aggregation zones are likely caused by low particle concentrations in the wake of the zones that only slowly recover due to Brownian motion and particle nucleation.

Active Microbial Airborne Dispersal and Biomorphs as Confounding Factors for Life Detection in the Cell-Degrading Brines of the Polyextreme Dallol Geothermal Field

Determining the precise limits of life in polyextreme environments is challenging. Studies along gradients of polyextreme conditions in the Dallol proto-volcano area (Danakil salt desert, Ethiopia) showed the occurrence of archaea-dominated communities (up to 99%) in several hypersaline systems but strongly suggested that life did not thrive in the hyperacidic (pH ∼0), hypersaline (∼35% [wt/vol],) and sometimes hot (up to 108°C) ponds of the Dallol dome. However, it was recently claimed that archaea flourish in these brines based on the detection of one Nanohaloarchaeotas 16S rRNA gene and fluorescent in situ hybridization (FISH) experiments with archaea-specific probes. Here, we characterized the diversity of microorganisms in aerosols over Dallol, and we show that, in addition to typical bacteria from soil/dust, they transport halophilic archaea likely originating from neighboring hypersaline ecosystems. We also show that cells and DNA from cultures and natural local halophilic communities are rapidly destroyed upon contact with Dallol brine. Furthermore, we confirm the widespread occurrence of mineral particles, including silica-based biomorphs, in Dallol brines. FISH experiments using appropriate controls show that DNA fluorescent probes and dyes unspecifically bind to mineral precipitates in Dallol brines; cellular morphologies were unambiguously observed only in nearby hypersaline ecosystems. Our results show that airborne cell dispersal and unspecific binding of fluorescent probes are confounding factors likely affecting previous inferences of archaea thriving in Dallol. They highlight the need for controls and the consideration of alternative abiotic explanations before safely drawing conclusions about the presence of life in polyextreme terrestrial or extraterrestrial systems.

Amorphous calcium carbonate monohydrate containing a defect hydrate network by mechanochemical processing of mono-hydrocalcite using ethanol as auxiliary solvent

Calcium carbonate monohydrate-like ACC was made by ball-milling with ethanol as auxiliary solvent. IR and solid-state NMR, diffraction and total scattering show that defects of the hydrate network due to partial displacement of water by ethanol are crucial for amorphization.

Nucleation kinetics of lithium phosphate precipitation

Fourth-order kinetics arises from the consecutive complexation leading to precipitation.

Silica-Carbonate of Ba(II) and Fe2+/Fe3+ Complex as Study Models to Understand Prebiotic Chemistry

The Precambrian era is called the first stage of the Earth history and is considered the longest stage in the geological time scale. Despite its duration, several of its environmental and chemical characteristics are still being studied. It is an era of special relevance not only for its duration but also because it is when a set of conditions gave rise to the first organism. This pioneer organism has been proposed to have been formed by a mineral and an organic part. A chemical element suggested to have been part of the structure of this cell is iron. However, what special characteristic does iron have with respect to other chemical elements to be proposed as part of this first cell? To answer this and other questions, it is indispensable to have a model that will allow extrapolating the first chemical structures of the pioneer organism formed in the Precambrian. In this context, for several decades, in vitro structures chemically formed by silica-carbonates have been synthetized, called biomorphs, because they could emulate living organisms and might resemble primitive organisms. It has been inferred that because biomorphs form structures with characteristic morphologies, they could resemble the microfossils found in the cherts of the Precambrian. Aiming at providing some insight on how iron contributed to the formation of the chemical structures of the primitive organism, we evaluated how iron contributes to the morphology and chemical-crystalline structure during the synthesis of these compounds under different conditions found in the primitive atmosphere. Experimentally, synthesis of biomorphs was performed at four different atmospheric conditions including UV light, nonionizing microwave radiation (NIR-mw), water steam (WS), and CO2 in the presence of Fe2+, Fe3+, and Fe2+/Fe3+, obtaining 48 different conditions. The produced biomorphs were observed under scanning electron microscopy (SEM). Afterward, their chemical composition and crystalline structure were analyzed through Raman and IR spectroscopy.

Recent advances in dopamine-based materials constructed via one-pot co-assembly strategy

Dopamine-based materials have attracted widespread interest due to the outstanding physicochemical and biological properties. Since the first report on polydopamine (PDA) films, great efforts have been devoted to develop new fabrication strategies for obtaining novel nanostructures and desirable properties. Among them, one-pot co-assembly strategy offers a unique pathway for integrating multiple properties and functions into dopamine-based platform in a single simultaneous co-deposition step. This review focuses on the state of the art development of one-pot multicomponent self-assembly of dopamine-based materials and summarizes various single-step co-deposition approaches, including PDA-assisted adaptive encapsulation, co-assembly of dopamine with other molecules through non-covalent interactions or covalent interactions. Moreover, emerging applications of dopamine-based materials in the fields ranging from sensing, cancer therapy, catalysis, oil/water separation to antifouling are outlined. In addition, some critical remaining challenges and opportunities are discussed to pave the way towards the rational design and applications of dopamine-based materials.

Local Light-Controlled Generation of Calcium Carbonate and Barium Carbonate Biomorphs via Photochemical Stimulation

Photochemical activation is proposed as a general method for controlling the crystallization of sparingly soluble carbonates in space and time. The photogeneration of carbonate in an alkaline environment is achieved upon photo‐decarboxylation of an organic precursor by using a conventional 365 nm UV LED. Local irradiation was conducted focusing the LED light on a 300 μm radius spot on a closed glass crystallization cell. The precursor solution was optimized to avoid the precipitation of the photoreaction organic byproducts and prevent photo‐induced pH changes to achieve the formation of calcium carbonate only in the corresponding irradiated area. The crystallization was monitored in real‐time by time‐lapse imaging. The method is also shown to work in gels. Similarly, it was also shown to photo‐activate locally the formation of barium carbonate biomorphs. In the last case, the morphology of these biomimetic structures was tuned by changing the irradiation intensity.

Influence of Abiotic Factors in the Chemical Origin of Life: Biomorphs as a Study Model

Since the formation of the Earth, minerals have been the key to understanding how life originated. It is suggested that life arose from minerals; they are considered to favor the formation and replication of biomolecules. In conjunction with minerals, the abiotic factors of the Precambrian era enabled the origin, development, and maintenance of life. To explain and understand the chemical origin of life, theories have been postulated for decades, and some of them have gone from mere postulates to evidence that have contributed to science in this direction. Several research groups have developed study models elucidating which could have been the first forms of life; in this sense, calcium, barium, or strontium silica carbonates have been synthesized in vitro to emulate morphologies of organisms. Aimed at understanding better the influence of abiotic factors in the formation of different chemical structures, the importance of the different types of physical and chemical abiotic factors in the origin of life are reviewed, as well as their influence on the morphology of biomorphs.

Water mediated growth of oriented single crystalline SrCO3 nanorod arrays on strontium compounds

Morphology-controlled strontianite nanostructures have attracted interest in various fields, such as electrocatalyst and photocatalysts. Basic additives in aqueous strontium solutions is commonly used in controlling strontianite nanostructures. Here, we show that trace water also serves an important role in forming and structuring vertically oriented strontianite nanorod arrays on strontium compounds. Using in situ Raman spectroscopy, we monitored the structural evolution from hydrated strontium to strontianite nanorods, demonstrating the epitaxial growth by vapor-liquid-solid mechanism. Water molecules cause not only the exsolution of Sr liquid droplets on the surface but also the uptake of airborne CO₂ followed by its ionization to CO₃^2-. The existence of intermediate SrHO⁺-OCO₂^2- phase indicates the interaction of CO₃^2- with SrOH⁺ in Sr(OH)_x(H₂O)_y cluster to orient strontianite crystals. X-ray diffraction simulation and transmission electron microscopy identify the preferred-orientation plane of the 1D nanostructures as the (002) plane, i.e., the growth along the c-axis. The anisotropic growth habit is found to be affected by the kinetics of carbonation. This study paves the way for designing and developing 1D architecture of alkaline earth metal carbonates by a simple method without external additives at room temperature.

Complex Morphogenesis by a Model Intrinsically Disordered Protein

The development of intricate and complex self-assembling structures in the micrometer range, such as biomorphs, is a major challenge in materials science. Although complex structures can be obtained from self-assembling materials as they segregate from solution, their size is usually in the nanometer range or requires accessory techniques. Previous studies with intrinsically disordered proteins (IDPs) have shown that the active interplay of different molecular interactions provides access to new and more complex nanostructures. As such, it is hypothesized that enriching the variety of intra- and intermolecular interactions in a model IDP will widen the landscape of sophisticated intermediate structures that can be accessed. In this study, a model silk-elastin-like recombinamer capable of interacting via three non-covalent interactions, namely hydrophobic, ion-pairing, and H-bonding is built. This model material is shown to self-assemble into complex stable micrometer-sized biomorphs. Variation of the block composition, pH, and temperature demonstrates the necessary interplay of all three interactions for the formation of such complex structures.

Shape-Preserving Chemical Conversion of Architected Nanocomposites

Forging customizable compounds into arbitrary shapes and structures has the potential to revolutionize functional materials, where independent control over shape and composition is essential. Current self-assembly strategies allow impressive levels of control over either shape or composition, but not both, as self-assembly inherently entangles shape and composition. Herein, independent control over shape and composition is achieved by chemical conversion reactions on nanocrystals, which are first self-assembled in nanocomposites with programmable microscopic shapes. The multiscale character of nanocomposites is crucial: nanocrystals (5-50 nm) offer enhanced chemical reactivity, while the composite layout accommodates volume changes of the nanocrystals (≈25%), which together leads to complete chemical conversion with full shape preservation. These reactions are surprisingly materials agnostic, allowing a large diversity of chemical pathways, and development of conversion pathways yielding a wide selection of shape-controlled transition metal chalcogenides (cadmium, manganese, iron, and nickel oxides and sulfides). Finally, the versatility and application potential of this strategy is demonstrated by assembling: 1) a scalable and highly reactive nickel catalyst for the dry reforming of butane, 2) an agile magnetic-controlled particle, and 3) an electron-beam-controlled reversible microactuator with sub-micrometer precision. Previously unimaginable customization of shape and composition is now achievable for assembling advanced functional components.

Tuning the Superhydrophobic Properties of Hierarchical Nano-microstructural Silica Biomorph Arrays Grown at Triphasic Interfaces

The three-dimensional hierarchical morphology of surfaces greatly affects the wettability, absorption and microfabrication properties of their hybrid materials, however few scalable methods exist that controls simultaneously complex geometric shape and spatial scattered location and their physical properties tuned. Consequently, this report describes a synthetic strategy that enables the position of well-ordered biomorph nano-microstructures on hydrophobic surfaces to be precisely controlled. The hierarchical architecture can be accurately positioned on polydimethylsiloxane (PDMS) surfaces in an unprecedented level by leveraging a solid/liquid/gas triphase dynamic reaction diffusion system strategy. The effect of salt concentrations, pH, CO₂ levels, temperature and substrate patterning on this self-assembly process has been investigated, enabling protocols to be devised that enables the hydrophobic properties of the hierarchically assembled multiscale microstructures to be tuned as required. This combined top-down/bottom-up approach can be used to produce composites with outstanding hydrophobicity properties, affording superhydrophobic materials that are capable of retaining water droplets on their surfaces, even when the material is inverted by 180°, with a wide range of potential applications in oil/water separation technology and for selective cell recognition in biological systems.

Carbon Nanolights in Piezopolymers are Self-Organizing Toward Color Tunable Luminous Hybrids for Kinetic Energy Harvesting

Herein, an all-solid-state sequential self-organization and self-assembly process is reported for the in situ construction of a color tunable luminous inorganic/polymer hybrid with high direct piezoresponse. The primary inorganic self-organization in solid polymer and the subsequent polymer self-assembly are achieved at high pressure with the first utilization of piezo-copolymer (PVDF-TrFE) as the host matrix of guest carbon quantum dots (CQDs). This process induces the spontaneous formation of a highly ordered, microscale, polygonal, and hierarchically structured CQDs/PVDF-TrFE hybrid with multicolor photoluminescence, consisting of very thermodynamic stable polar crystalline nanowire arrays. The electrical polarization-free CQDs/PVDF-TrFE hybrids can efficiently harvest the environmental available kinetic mechanical energy with a new large-scale group-cooperation mechanism. The open-circuit voltage and short-circuit current outputs reach up to 29.6 V cm^-2 and 550 nA cm^-2 , respectively. The CQDs/PVDF-TrFE-based hybrid nanogenerator demonstrates drastically improved durable and reliable features during the real-time demonstration of powering commercial light emitting diodes. No attenuation/fluctuation of the electrical signals is observed for ≈10 000 continuous working cycles. This study may offer a new design concept for progressively but spontaneously constructing novel multiple self-adaptive complex inorganic/polymer hybrids that promise applications in the next generation of self-powered autonomous optoelectronic devices.

From nonlinear reaction-diffusion processes to permanent microscale structures

Biomorphs are polycrystalline aggregates that self-assemble during inorganic precipitation reactions. The shape repertoire of these microstructures include hemispherical objects with complicated internal features such as radial spikes and cones as well as folded sheets reminiscent of corals. We propose that at the microscale, some of these patterns are caused by nonlinear reaction-diffusion processes and present a simple model for this unconventional type of precipitation. The model consists of three reaction steps that convert a reactant species autocatalytically into an intermediate and eventually into a solid, immobile product. Numerical simulations of the model in three space dimensions reveal product structures that are similar to the experimentally observed biomorphs.

Hybrid Biomimetic Materials from Silica/Carbonate Biomorphs

The formation of a polymer protection layer around fragile mineral architectures ensures that structures stay intact even after treatments that would normally destroy them going along with a total loss of textural information. Here we present a strategy to preserve the shape of silica-carbonate biomorphs with polymers. This method converts non-hybrid inorganic-inorganic composite materials such a silica/carbonate biomorphs into hybrid organic/carbonate composite materials similar to biominerals.