Crystal Nucleation Research Articles

Effects of structure similar additive on the crystallization of L-phenylalanine from aqueous solution

A comprehensive understanding of the effect of structure similar additives on the nucleation and growth of amino acid in aqueous solution is of great significance for the crystallization of L-phenylalanine and industrial production of anhydrous L-phenylalanine. This paper mainly focuses on the influence of L-tyrosine on the crystallization process of L-phenylalanine by investigating the variation and typical phenomenon in solubility, metastable zone width, crystal nucleation and growth process, and crystal morphology. The results show that the existence of L-tyrosine can obviously increase the solubility and narrow the metastable zone of L-phenylalanine thus promote the nucleation process. Meanwhile, L-tyrosine can also selectively inhibit the formation of monohydrate and improve the purity of industry-favored anhydrous L-phenylalanine in the final product. In order to explore the inhibiting effect of L-tyrosine in crystallization process, the molecular configurations in two different crystallization states were simulated by using Molecular Dynamics.The results show that water and L-phenylalanine molecules tend to form anhydrous crystals when the addition proportion of L-tyrosine increases. The theoretical calculations are in good agreement with the experimental data. The conclusions of this paper will provide new ideas and effective controlling approaches for L-phenylalanine crystals’ morphology and amino acids’ crystallization process.

Highly efficient and thermally stable photonic ceramic by controllable and full crystallization from glass

Polycrystalline ceramics are promising for a diverse range of applications in solid state laser, lighting, scintillator and optical storage. Unfortunately, current ceramic elaborations involves strict and complex synthetic procedures such as ultra-high pressure and vacuum processing. Here, we realize the tune of MgAl2Si4O12 and Mg2Al4Si5O18 phase formation in a glass by controlling the two crystal nucleation and growth individually, and obtain a polycrystalline non-stoichiometric Mg2-x/2Al4-xSi5+xO18:Eu2+ translucent ceramic by virtue of complete and congruent crystallization of the glass. Microstructural characterizations verify that the resulting ceramic exhibits dense and closely stacked micrometer-scale crystallites with very thin grain boundary structure. Chemical composition analysis by energy dispersive X-ray spectrometry revels the grain's composition is highly deviated from the stoichiometric Mg2Al4Si5O18, with atomic ratio Mg/Al/Si of 1.00: 1.46: 2.70. The precipitated non-stoichiometric Mg2-x/2Al4-xSi5+xO18, structurally having infinite channels z = 0.25 or 0.75 sites that run parallel to the c-aix, provides an robust crystal-field environment for Eu2+ 5d-4f transition. As a consequence, the ceramic produces intense emission with photoluminescence quantum yield (PLQY) up to 90 %, and excellent thermal stability emission with 70.1 % emission intensity at 420 K relative to that at room temperature, demonstrating it can be applied in high power lighting application with improved light quality by employing the ceramic as a color converter. Moreover, the ceramic also exhibits thermally stimulated luminescence at temperature reaching up to 700 K, originating from the deep electronic traps in Mg2-x/2Al4-xSi5+xO18 lattice with estimated trap depth of 0.73eV and 0.97eV. We also demonstrate the ceramic is hopeful for optical information storage application as the storage information can be retain well without vulnerable by the fluctuations of external environments due to the deep traps.

A microscopic approach to crystallization: Challenging the classical/non-classical dichotomy.

We present a fundamental framework for the study of crystallization based on a combination of classical density functional theory and fluctuating hydrodynamics that is free of any assumptions regarding order parameters and that requires no input other than molecular interaction potentials. We use it to study the nucleation of both droplets and crystalline solids from a low-concentration solution of colloidal particles using two different interaction potentials. We find that the nucleation pathways of both droplets and crystals are remarkably similar at the early stages of nucleation until they diverge due to a rapid ordering along the solid pathways in line with the paradigm of "non-classical" crystallization. We compute the unstable modes at the critical clusters and find that despite the non-classical nature of solid nucleation, the size of the nucleating clusters remains the principle order parameter in all cases, supporting a "classical" description of the dynamics of crystallization. We show that nucleation rates can be extracted from our formalism in a systematic way. Our results suggest that in some cases, despite the non-classical nature of the nucleation pathways, classical nucleation theory can give reasonable results for solids but that there are circumstances where it may fail. This contributes a nuanced perspective to recent experimental and simulation work, suggesting that important aspects of crystal nucleation can be described within a classical framework.

Phase diagram of NaCl–water by computer simulations: performance of non-polarizable force-fields

This study evaluates the capabilities of two new ion force fields (Tanaka [Yagasaki et al. JCTC 2020] and Madrid-2019 [Zerón et al. JCP 2019]) in conjunction with the TIP4P/2005 model for water in reproducing the NaCl–water phase diagram using molecular dynamics direct coexistence simulations. The performance of those force-fields is critically compared with the phase diagram recently reported for the Joung Cheatham-TIP4P/2005 force-field [Bianco et al. JCP 2022]. Excellent agreement between the three force-fields and experiments is found for the ice-solution line due to the dominance of the water model in the location of this line. For the NaCl-solution line, the Tanaka and the Madrid-2019 models accurately predict solubility at ambient temperature, but they underestimate somewhat the experimental line as temperature increases. The JC model underestimates NaCl solubility both at ambient and at high temperatures. All models underestimate the stability of the NaCl·2H 2 O solid, which remains metastable with respect to NaCl. Equilibration of the NaCl·2H 2 O-solution system is challenging at low temperatures due to the slow diffusion of concentrated NaCl solutions. The phase diagrams obtained serve as a foundation for studying crystal nucleation, and solid-solution interfaces, and provide very valuable information for the development of imporved NaCl–H 2 O force-fields.

Electrochemically Assisted Single Crystal Growth of Reduced Preyssler Polyoxometalates Decorated with M2+ (M = Co, Ni) and Cubane-Like Ni4O4 Units.

Polyoxometalates (POMs) are of great interest to the scientific community, and their reduction and nucleation have been well-established by multi-step techniques. The present study develops an electrochemical approach for simultaneous reduction and nucleation of polyoxometalate-containing solids. Herein we report crystal growth of reduced Preyssler polyoxotungstate-based (anionic formula [NaP5W30O110]14-) new crystalline solids made of Preyssler anions interlinked by Co2+ and Ni2+ ions. Crystal nucleation and in situ reduction were achieved at room temperature using a two silver wire electrode setup in various aqueous solutions under constant applied potentials. The POM material was deposited on the cathode, and its structure was characterized by X-ray diffraction techniques. The primary structure type observed involves POMs decorated by disordered Co2+/Ni2+ octahedra and fused into 1-D pillars by additional Co2+/Ni2+ octahedra. A secondary phase was observed in the Ni-based reactions, where reduced Preyssler anions are decorated by Ni4O4 cubane-like units. To understand the electrochemical process, polarization curves of the electrolyte solutions are presented, suggesting an applied potential best suited for crystal growth. The work highlights the effectiveness of an electrochemical pathway where nucleation and simultaneous reduction of POMs can make novel reduced POM solids.

Epitaxial Growth of Two-Dimensional Organic Crystals with In-Plane Heterostructured Domain Regulation.

Complex organic lateral heterostructures (OLHs) with spatial distribution of two or more chemical components are crucial for designing and realizing unique structure-dependent optoelectronic applications. However, the precise design of well-defined OLHs with flexible domain regulation remains a considerable challenge. Herein, we present a stepwise solution self-assembly method to synthesize two-dimensional (2D) OLHs with a central rhombus domain and a lateral region featuring tunable blue and green emission based on the sequential nucleation and growth of 2D crystals. By controlling the initial crystallization time of 2,6-diphenylanthracene, the rhombic length ratio (α) of the multicolor-emissive part of the 2D OLHs is precisely modified. Furthermore, a third lateral layer is constructed on the resulting OLHs, demonstrating scalable lateral regulation. Significantly, these prepared 2D OLHs exhibit great excitation position-dependent waveguide characteristics and enable a 0.06 dB/μm low-loss waveguiding, which are conducive to photon transport and conversion for photonic integrated circuits. This work provides a stepwise strategy for the accurate fabrication of 2D OLHs, fabricating the developments of next-generation optoelectronics devices.

Sand improvement by microbial-induced carbonate precipitation with casein micelles

This study explores the incorporation of casein micelles to improve the conventional microbial-induced carbonate precipitation technique used for soil improvement. With a single application of the proposed biocementing agent containing casein micelles, a mixed slurry of natural sand solidified to self-sustaining strength within 48 h at 37°C was obtained. The stress–strain curves of the biocemented specimens obtained from a consolidated drained triaxial compression test exhibited sharp peaks at less than 1% strain. Under effective confining pressures of 30, 50 and 100 kPa, the peak deviatoric stress registered 415, 479 and 536 kPa, respectively – representing 1·8–4·1 times the maximum strength of the original sand. Vaterite calcium carbonate crystals formed by the biocementing agent ensured bridging between sand particles, resulting in the improved cohesion. The cohesion-derived residual strength tended to increase at the critical state in biocemented sand under the lowest confining stress. The localised shear band formed by the crystals may control the movement of sand particles, resulting in a change in volumetric strain behaviour. The formation of casein micelles induced the nucleation and growth of spherical crystals, acting as a casein-mediated vaterite. This formation likely contributed to the improved cohesion of sand observed in this study.

The rise and fall of adenine clusters in the gas phase: a glimpse into crystal growth and nucleation.

The emergence of a crystal nucleus from disordered states is a critical and challenging aspect of the crystallization process, primarily due to the extremely short length and timescales involved. Methods such as liquid-cell or low-dose focal-series transmission electron microscopy (TEM) are often employed to probe these events. In this study, we demonstrate that ion mobility spectrometry-mass spectrometry (IMS-MS) offers a complementary and insightful perspective on the nucleation process by examining the sizes and shapes of small clusters, specifically those ranging from n = 2 to 40. Our findings reveal the significant role of sulfate ions in the growth of adeninediium sulfate clusters, which are the precursors to the formation of single crystals. Specifically, sulfate ions stabilize adenine clusters at the 1:1 ratio. In contrast, guanine sulfate forms smaller clusters with varied ratios, which become stable as they approach the 1:2 ratio. The nucleation size is predicted to be between n = 8 and 14, correlating well with the unit cell dimensions of adenine crystals. This correlation suggests that IMS-MS can identify critical nucleation sizes and provide valuable structural information consistent with established crystallographic data. We also discuss the strengths and limitations of IMS-MS in this context. IMS-MS offers rapid and robust experimental protocols, making it a valuable tool for studying the effects of various additives on the assembly of small molecules. Additionally, it aids in elucidating nucleation processes and the growth of different crystal polymorphs.

Two-step crystallization in a supersaturated solution with application to protein crystal growth: Theory and analytical solutions

A theory of two-step nucleation and evolution of crystals with allowance for their diffusion in the space of particle radii is developed. The theory is based on a two-step growth law of crystals appearing in dense liquid precursors, initially evolving within them with a diffusion-limited growth law, and then leaving them and evolving with another growth law. This two-step crystal growth law influences the integrodifferential system of kinetic and balance equations for the crystal-size distribution function and liquid supersaturation. The system of integrodifferential equations for the evolution of polydisperse ensemble of crystals is solved using the integral Laplace transform and saddle-point methods for the Weber–Volmer–Frenkel–Zel’dovich and Meirs kinetic mechanisms. A complete analytical solution to this non-linear system has been constructed in a parametric form. Namely, the particle-size distribution function, liquid supersaturation and time have been found as the functions of decision variable — the maximum size of crystals. The theory is in agreement with the experimental data on the growth of beta-lactoglobulin and insulin crystals.

Investigation of the effect of Tideglusib on the hydroxyapatite formation, crystallinity and elasticity of conditioned resin-dentin interfaces

To investigate the effect of dentin infiltration with polymeric nanoparticles (NPs) doped with tideglusib (TDg) (TDg-NPs) on hydroxyapatite formation, crystallinity and elasticity of conditioned resin-dentin interfaces. Dentin conditioned surfaces were infiltrated with NPs or TDg-NPs. Bonded interfaces were created, stored for 24 h and submitted to mechanical and thermal challenging. Resin-dentin interfaces were evaluated through nanoindentation to determine the modulus of elasticity, X-ray diffraction and transmission electron microscopy through selected area diffraction and bright-filed imaging. TDg-NPs provoked peaks narrowing after the diffraction-intensity analysis that corresponded with high crystallinity, with an increased modulus of Young after load cycling in comparison with the samples treated with undoped NPs. New minerals, in the group of TDg-NPs, showed the greatest both deviation of line profile from perfect crystal diffraction and dimension of the lattice strain, i.e., crystallite, grain size and microstrain and 002 plane-texture. The new minerals generated after TDg-NPs application and mechanical loading followed a well defined lineation. Undoped NPs mostly produced small hydroxyapatite crystallites, non crystalline or amorphous in nature with poor maturity. Tideglusib promoted the precipitation of hydroxyapatite, as a major crystalline phase, at the intrafibrillar compartment of the collagen fibrils, enabling functional mineralization. TDg-NPs facilitated nucleation of crystals randomly oriented, showing less structural variation in angles and distances that improved crystallographic relative order of atoms and maturity. Nanocrystals inducted by TDg-NPs were hexagonal prisms of submicron size. Thermal challenging of dentin treated with TDg-NPs have provoked a decrease of functional mineralization and crystallinity, associated to immature hydroxyapatite. New polycrystalline lattice formation generated after TDg-NPs infiltration may become correlated with high mechanical performance. This association can be inferred from the superior crystallinity that was obtained in presence of tideglusib. Immature crystallites formed in dentin treated with undoped NPs will account for a high remineralizing activity.

Simple and sustainable synthesis of loosely stacked nano-H-ZSM-5 aggregates from kaolin and catalytic studies

The conversion of natural clay to crystalline zeolites has been the subject of considerable interest from both academic and industrial circles. We present an effective strategy for converting kaolin to ZSM-5 zeolite, addressing the issue of reduced mesopore formation in conventional nano-ZSM-5 aggregates due to close-packing. This strategy utilizes kaolin as the sole source of silicon and aluminum, and by decoupling the nucleation and growth of ZSM-5 crystals, loosely stacked nano-H-ZSM-5 aggregates with high crystallinity crystals can be synthesized in a solid-like system by employing a tiny amount of TPAOH (TPAOH/SiO2 = 0.064). The resulting nano-H-ZSM-5 aggregates exhibited high specific surface area (405.66 m2/g), high mesopore volume (0.64 cm3/g), and superior catalytic activity. This strategy offers a novel approach to the cost-effective synthesis of nano-H-ZSM-5 aggregates suitable for industrial applications.

Influence of micromixing and shear on precipitation process in the jet-flow high shear reactors

Micromixing and fluid shear stress significantly affect the nucleation and growth of crystals during the precipitation process. The jet-flow high shear reactor (JFHSR) has strong shear rate and high localized energy dissipation rate, making it promising for applications where the size and the morphology of crystals need to be modified. In this paper, the micromixing properties of JFHSR were first investigated using Villermaux/Dushman method, and the intrinsic correlation among micromixing, shear, and BaSO4 crystals was explored. The results show that the stator, the increased Re and θ, the reduced feed tube diameter and the closer the feed position to the rotor promote micromixing. Excellent micromixing promotes burst nucleation by generating uniform supersaturation, while shear is more likely to provide an environment dominated by the secondary nucleation of fluid shear stress. The correlations of XS, tm (about 10−4 s) and d43,P are obtained, providing guidelines for JFHSR design and application

Construction of tree-ring mimetic 3D networks in polyvinyl alcohol/boron nitride composites for enhanced thermal management and mechanical properties

Constructing a three-dimensional (3D) filler network in polymer thermal interface materials (TIMs) is crucial for enhancing thermal conductivity and mechanical properties. However, the discontinuous and loose network of fillers are one of the main reasons hindering the joint improvement of thermal conductivity and mechanical properties. The construction of a regular and dense 3D continuous filler network remains a significant challenge. In this study, an innovative bidirectional freezing technique was designed to create a polyvinyl alcohol (PVA)/boron nitride (BN) composite with a tree-ring-like 3D network. This technique promotes the formation of 3D network consisting of long-range lamellar BN layers with a tree-ring-like structure by controlling the nucleation and growth of ice crystals along the bidirectional temperature gradient induced by a polytetrafluoroethylene (PTFE) cone. The resulting PVA/BN composite exhibits high thermal conductivity (6.25 W/m·K) due to the lower interfacial thermal resistance between fillers (1.271 × 10−7 K m2/W), and an enhanced tensile strength of 41.71 MPa, which is attributed to the regular and dense BN network. This study presents a feasible strategy for constructing a 3D continuous network structure in polymer-based TIMs, paving the way for advancements in thermal management solutions.

The interactions of protein-calcium oxalate in crystallization process

Understanding the pathogenic crystallization of calcium oxalate (CaOx), a major constituent of kidney stones, is crucial in developing effective treatment strategies. In this work, the interactions between lysozyme and CaOx during crystallization have been investigated. Further investigations into the crystal morphology, size, quantity, and nucleation time of the lysozyme have been designed. The results reveal that CaCl2 could act as an effective precipitant for lysozyme crystallization. The formation process and structure of the distinctive composite CaOx-lysozyme crystal has been investigated. The addition of lysozyme promoted the formation of individual CaOx crystals by preventing the crystal aggregation in the solution. The presence of lysozyme induced a transformation in the CaOx crystals from calcium oxalate monohydrate to calcium oxalate dihydrate. These findings contribute to a better understanding of protein-CaOx interactions and their implications in kidney stone pathogenesis.

Templated Nucleation of Clotrimazole and Ketoprofen on Polymer Substrates.

The use of different template surfaces in crystallization experiments can directly influence the nucleation kinetics, crystal growth, and morphology of active pharmaceutical ingredients (APIs). Consequently, templated nucleation is an attractive approach to enhance crystal nucleation kinetics and preferentially nucleate desired crystal polymorphs for solid-form drug molecules, particularly large and flexible molecules that are difficult to crystallize. Herein, we investigate the effect of polymer templates on the crystal nucleation of clotrimazole and ketoprofen with both experiments and computational methods. Crystallization was carried out in toluene solvent for both APIs with a template library consisting of 12 different polymers. In complement to the experimental studies, we developed a computational workflow based on molecular dynamics (MD) and derived descriptors from the simulations to score and rank API-polymer interactions. The descriptors were used to measure the energy of interaction (EOI), hydrogen bonding, and rugosity (surface roughness) similarity between the APIs and polymer templates. We used a variety of machine learning models (14 in total) along with these descriptors to predict the crystallization outcome of the polymer templates. We found that simply rank-ordering the polymers by their API-polymer interaction energy descriptors yielded 92% accuracy in predicting the experimental outcome for clotrimazole and ketoprofen. The most accurate machine learning model for both APIs was found to be a random forest model. Using these models, we were able to predict the crystallization outcomes for all polymers. Additionally, we have performed a feature importance analysis using the trained models and found that the most predictive features are the energy descriptors. These results demonstrate that API-polymer interaction energies are correlated with heterogeneous crystallization outcomes.

Simulating Crystallization in a Colloidal System Using State Predictive Information Bottleneck Based Enhanced Sampling.

We investigate crystal nucleation in supersaturated colloid suspensions using enhanced molecular dynamics simulations augmented with machine learning techniques. The simulations reveal that crystallization in the model colloidal system studied here, with particles interacting through a repulsive screened Coulomb Yukawa potential, proceeds from vapor to dense liquid droplet to crystalline phases across multiple high barriers. Employing a one-dimensional reaction coordinate derived from the State Predictive Information Bottleneck framework, our simulations capture back-and-forth phase transitions across multiple barriers effectively in biased metadynamics simulations. We obtain relative free energy differences between different phases and also quantify the roles of different molecular level features in driving the phase changes.

Identifying crystal nucleation mechanisms in a synthetic trachybasalt: a multimodal approach

To develop new criteria to distinguish different crystal nucleation mechanisms in silicate melts, we performed crystallization experiments using a synthetic hydrous (2 wt% H2O) trachybasalt and combined three-dimensional information from synchrotron X-ray computed microtomography with two-dimensional mapping of crystallographic orientation relationships (CORs) using electron backscatter diffraction. Crystallization experiments were performed at 400 MPa by cooling the melt from 1300 °C to resting temperatures of 1150 and 1100 °C and maintaining isothermal conditions for 30 min and 8 h. Three distinct titanomagnetite (Tmt) populations formed: (1) skeletal crystals, isolated or partially embedded in clinopyroxene (Cpx); (2) anhedral crystals, always attached to Cpx; (3) flattened needle-shaped crystals, embedded in Cpx. These morphologically different Tmt populations formed in response to one cooling event, with varying nucleation mechanisms and at different undercooling conditions. The clustered three-dimensional distribution of population 2 and 3 Tmt grains and the high proportion of Tmt-Cpx interfaces sharing CORs indicate that these Tmt grains heterogeneously nucleated on Cpx. The near-random three-dimensional distribution of (often isolated) population 1 Tmt grains, together with the low proportion of Tmt-Cpx interfaces sharing CORs, imply their isolated, possibly homogeneous nucleation, potentially followed by heterogeneous nucleation of Cpx on population 1 Tmt. Heterogeneous nucleation in slightly to moderately undercooled magmas should affect the sequence of crystallization as well as morphology and clustering of crystals, which may actively contribute to the variation of rheological parameters like viscosity. Finally, observed intra- and inter-sample variations in Tmt-Cpx COR frequencies indicate the potential for this parameter to record further petrological information.

Effect of wet grinding carbonation of sintering red mud on the performance of carbon sequestered mortar

The use of alkaline solid waste to CO2 capture is a potential way to upgrade the recycling of solid waste and reduce CO2 emission. In previous work, we proposed a novel wet grinding carbonation technique to achieve rapid carbonation of sintering red mud (SRM). Herein, the effect of wet grinding carbonation of SRM (WGCS) replacement rate (0 %, 5 %, 10 %, 15 %, 20 % and 25 %) on the hydration and hardening of Portland cement was further explored, such as rheology, compressive strength, hydration products and water transfer properties. The plastic viscosity and yield stress of carbon sequestered paste rose together with the WGCS replacement rate, which was due to the decreased D50 of SRM after wet grinding carbonation. When the WGCS replacement rate was 15 %, the 56 d compressive strength of carbon sequestered mortar was increased by 14.1 %. The microscopic characterization showed that the nucleation of calcite crystals and the pozzolanic reaction of silica-rich gels clearly improved the microstructure compactness. The electric flux and porosity of cement mortar was decreased by 25.7 % and 11.4 %, respectively. In terms of environmental and economic benefits, the CO2 sequestration of carbon sequestered mortar reached as high as 24.7 kg/m3 and the CO2 emission was reduced by 30.9 %.

Stereoselective Crystallization of Chiral Pharmaceuticals Aided by Cellulose Derivatives through Helical Pattern Matching.

Stereoselective inhibition aided by "tailor-made" polymeric additives is an efficient approach to obtain enantiopure compounds through conglomerate crystallization. The chemical and configurational match between the side groups of polymers and the molecules of undesired enantiomer is considered to be a necessary condition for successful stereoseparation. Whereas in this contribution, we present an effective resolution of chiral pharmaceuticals by using cellulose acetates as the additives, which stereoselectively reside on the specific crystal faces of one enantiomer and inhibit its crystal nucleation and growth through helical pattern and supramolecular interaction complementarity. An investigation of nimodipine serves as a case study to highlight the novelty of this strategy wherein R-crystals exhibiting an impressive enantiomeric excess value of 97 % can be attained by employing a mere 0.01 wt % cellulose acetate. Guaifenesin and phenyl lactic acid are also well-resolved by utilizing this methodology. Our work not only brings about a brand-new design strategy for "tailor-made" additives, but will also promote the further exploration of the endless potential for utilizing natural biomolecules in chiral recognition and resolution.

Iodine-induced self-depassivation strategy to improve reversible kinetics in Na-Cl2 battery

Rechargeable sodium-chlorine (Na-Cl2) batteries show high theoretical specific energy density and excellent adaptability for extreme environmental applications. However, the reported cycle life is mostly less than 500 cycles, and the understanding of battery failure mechanisms is quite limited. In this work, we demonstrate that the substantially increased voltage polarization plays a critical role in the battery failure. Typically, the passivation on the porous cathode caused by the deposition of insulated sodium chloride (NaCl) is a crucial factor, significantly influencing the three-phase chlorine (NaCl/Na+, Cl-/Cl2) conversion kinetics. Here, a self-depassivation strategy enabled by iodine anion (I-)-tuned NaCl deposition was implemented to enhance the chlorine reversibility. The nucleation and growth of NaCl crystals are well balanced through strong coordination of the NaI deposition-dissolution process, achieving depassivation on the cathode and improving the reoxidation efficiency of solid NaCl. Consequently, the resultant Na-Cl2 battery delivers a super-long cycle life up to 2000 cycles.