Showing papers on "Nucleation published in 2004"
TL;DR: In this paper, the formation rate of 3-nm particles is often in the range 0.01-10 cm −3 s −1 in the boundary layer in urban areas and in coastal areas and industrial plumes.
2,028 citations
TL;DR: Observations of nanocrystalline nickel films with an average grain size of about 10 nanometers show that grain boundary–mediated processes have become a prominent deformation mode, and trapped lattice dislocations are observed in individual grains following deformation.
Abstract: The plastic behavior of crystalline materials is mainly controlled by the nucleation and motion of lattice dislocations. We report in situ dynamic transmission electron microscope observations of nanocrystalline nickel films with an average grain size of about 10 nanometers, which show that grain boundary-mediated processes have become a prominent deformation mode. Additionally, trapped lattice dislocations are observed in individual grains following deformation. This change in the deformation mode arises from the grain size-dependent competition between the deformation controlled by nucleation and motion of dislocations and the deformation controlled by diffusion-assisted grain boundary processes.
784 citations
TL;DR: In this paper, the influence of the choice of complexing ligand, zinc counter-ion, pH, ionic strength, supersaturation, deposition time and substrate on the nature of ZnO films grown from chemical baths (CBD) are discussed.
Abstract: The influence of the choice of complexing ligand, zinc counter-ion, pH, ionic strength, supersaturation, deposition time and substrate on the nature of ZnO films grown from chemical baths (CBD) are discussed. There are significant differences between CBD and similar routes such as hydrothermal methods for ZnO films. Modelling of speciation and experimental results suggest that acicular ZnO morphologies are best obtained by limiting the concentration of one of either Zn2+ or OH− in the presence of a large excess of the other. The presence of a prior ZnO layer can facilitate nucleation at lower levels of supersaturation and enable size tailoring of ZnO columns. The point at which the substrate is introduced into the bath is crucial and can lead to a significant difference in both the width of the rods and optical transparency of the films. HR-TEM has yielded important structural information and a growth mechanism for single crystalline ZnO rods by CBD is described for the first time.
747 citations
TL;DR: The results imply that the interaction between organic and sulfuric acids promotes efficient formation of organic and sulfate aerosols in the polluted atmosphere because of emissions from burning of fossil fuels, which strongly affect human health and global climate.
Abstract: Atmospheric aerosols often contain a substantial fraction of organic matter, but the role of organic compounds in new nanometer-sized particle formation is highly uncertain. Laboratory experiments show that nucleation of sulfuric acid is considerably enhanced in the presence of aromatic acids. Theoretical calculations identify the formation of an unusually stable aromatic acid-sulfuric acid complex, which likely leads to a reduced nucleation barrier. The results imply that the interaction between organic and sulfuric acids promotes efficient formation of organic and sulfate aerosols in the polluted atmosphere because of emissions from burning of fossil fuels, which strongly affect human health and global climate.
733 citations
TL;DR: In this paper, high-resolution transmission electron microscopy studies showed that ZnO nanorods are single crystals and that they grow along the c axis of the crystal plane.
Abstract: Uniformly distributed ZnO nanorods have been grown by plasma-enhanced chemical vapor deposition using a two-step process. By controlling the oxygen content in the gas mixture during the nucleation and growth steps, no catalyst is required for the formation of ZnO nanorods. High-resolution transmission electron microscopy studies show that ZnO nanorods are single crystals and that they grow along the c axis of the crystal plane. Alignment of these nanorods with respect to the substrates depends on the lattice mismatch between ZnO and the substrate, the surface electric field, and the amount of defects in the starting nuclei. Room-temperature photoluminescence measurements of these ZnO nanorods have shown ultraviolet peaks at 380 nm with a full width at half-maximum of 106 meV, which are comparable to those found in high-quality ZnO films. Photoluminescence measurements of annealed ZnO nanorods in hydrogen and oxygen atmospheres indicate that the origins of green emission are oxygen vacancies and zinc inter...
667 citations
TL;DR: Results indicate that the nature of the stabilizer emulsifier, the surface activity of additives and the colloidal stability of microemulsion droplets play decisive role on the particle size and distribution during the preparation of metal particles.
644 citations
TL;DR: In this article, the isothermal tetragonal-to-monoclinic transformation of a 3Y-TZP ceramic was investigated from 70° to 130°C in water and in steam by X-ray diffraction and optical interferometer techniques.
Abstract: The isothermal tetragonal-to-monoclinic transformation of a 3Y-TZP ceramic is investigated from 70° to 130°C in water and in steam by X-ray diffraction and optical interferometer techniques. Aging kinetics followed by X-ray diffraction are fitted by the Mehl-Avrami-Johnson law, suggesting nucleation and growth to be the key mechanisms for transformation. Optical interferometer observations of highly polished samples effectively reveal a nucleation and growth micromechanism for tetragonal-to-monoclinic transformation. A model based on surface change analysis is developed that fits closely to the X-ray diffraction results.
610 citations
TL;DR: In this article, an electrochemical mechanism for rod formation is proposed, whereby the flux of AuI bound to cationic micelles to the seed surface is maximized at points of highest curvature, where the electrical double layer gradient is highest.
Abstract: The factors affecting the nucleation and growth of gold nanorods, (Jana et al., Adv. Mater.2001, 13, 1389) have been investigated. It is shown that the size and aspect ratio can be controlled through the use of different sized seed particles. The length of the rods can be tuned from 25–170 nm, while the width remains almost constant at 22–25 nm. The formation of rods requires the presence of the cationic surfactant cetyltrimethylammonium bromide (CTAB). Lower temperature favors rod formation, although this reduces CTAB solubility. The addition of chloride ions or the use of dodecyltrimethylammonium bromide (DTAB) leads to shorter-aspect rods. AuIII and AuI are shown to be quantitatively bound to the CTAB micelles. We propose an electrochemical mechanism for rod formation, whereby the flux of AuI bound to cationic micelles to the seed surface is maximized at points of highest curvature, where the electrical double layer gradient is highest. Initial numerical solutions to the electric potential and field around an ellipsoid in a 1:1 electrolyte are provided, which indicate that the field at the particle tip scales linearly with the aspect ratio. Mean free passage times for ions are found to be shortest at the tips. The results provide a general explanation for the formation of non-equilibrium crystal habits and a mechanism for controlling crystal growth.
539 citations
TL;DR: Nanoparticle and nanocluster precursors may play a major role in biomineralization and the Ostwald step rule, based on a thermodynamic view of nucleation and growth, is supported by the observation that more metastable phases tend to have lower surface energies.
Abstract: Nanoparticle and nanocluster precursors may play a major role in biomineralization. The small differences in enthalpy and free energy among metastable nanoscale phases offer controlled thermodynamic and mechanistic pathways. Clusters and nanoparticles offer concentration and controlled transport of reactants. Control of polymorphism, surface energy, and surface charge on nanoparticles can lead to morphological control and appropriate growth rates of biominerals. Rather than conventional nucleation and growth, assembly of nanoparticles may provide alternative mechanisms for crystal growth. The Ostwald step rule, based on a thermodynamic view of nucleation and growth, is supported by the observation that more metastable phases tend to have lower surface energies. Examples from nonbiological systems, stressing the interplay of thermodynamic and kinetic factors, illustrate features potentially important to biomineralization.
458 citations
TL;DR: Platinum nanowires of approximately 100 nm in length and approximately 5 nm in diameter have been synthesized by reducing H(2)PtCl(6) with ethylene glycol in the presence of poly(vinyl pyrrolidone) (PVP) and a trace amount of Fe(3+) or Fe(2+).
Abstract: Platinum nanowires of approximately 100 nm in length and approximately 5 nm in diameter have been synthesized by reducing H(2)PtCl(6) with ethylene glycol in the presence of poly(vinyl pyrrolidone) (PVP) and a trace amount of Fe(3+) or Fe(2+). The wires were generated at the final stage of the synthesis, which involved the formation of several intermediate species. The Fe(3+) or Fe(2+) ions had dual functions in the synthesis: they induced aggregation of Pt nanoparticles into larger structures that served as the nucleation sites, and they greatly reduced the reaction rate and supersaturation level to induce anisotropic growth. The reaction mechanism was studied by X-ray photoelectron spectroscopy (XPS) and UV-vis spectral analysis. The Pt nanowires could be readily separated from the surfaces of the agglomerates by sonication and obtained as pure samples by centrifugation.
457 citations
TL;DR: In this article, the authors investigated the character of plastic deformation in metallic glasses through instrumented nanoindentation experiments on amorphous Pd40Ni40P20 and Mg65Cu25Gd10.
TL;DR: Titanium treated in NaOH can form hydroxycarbonated apatite (HCA) after exposition in simulated body fluid (SBF) and the treatment of titanium by acid etching in HCl and subsequently in Naoh is a suitable method for providing the metal implant with bone-bonding ability.
TL;DR: In this paper, the authors discuss experimental tests of the applicability of this mechanism to the nucleation of ordered solid phases: crystals or linear, planar, branched, or otherwise ordered aggregates of proteins and small molecule materials from solution.
Abstract: A line of recent theories and simulations have suggested that the nucleation of protein crystals might, under certain conditions, proceed in two steps: the formation of a droplet of a dense liquid, metastable with respect to the crystalline state, followed by ordering within this droplet to produce a crystal. In this review, I discuss experimental tests of the applicability of this mechanism to the nucleation of ordered solid phases: crystals or linear, planar, branched, or otherwise ordered aggregates of proteins and small molecule materials from solution. The main arguments stem from recent results on the kinetics of homogeneous nucleation of crystals of the protein lysozyme. These results indicate that under a very broad range of conditions the nucleation of lysozyme crystals occurs via a modification of the theoretically postulated mechanismas a superposition of fluctuations along the order parameters density and structure. Depending on whether the system is above or below its liquid−liquid coexiste...
TL;DR: It is found that to be effective crystallization promoters, the seed particles need to exceed a well-defined minimum size, just above which they act as crystallization ‘catalysts’ as newly formed crystallites detach from the seed.
Abstract: The addition of small 'seed' particles to a supersaturated solution can greatly increase the rate at which crystals nucleate. This process is understood, at least qualitatively, when the seed has the same structure as the crystal that it spawns. However, the microscopic mechanism of seeding by a 'foreign' substance is not well understood. Here we report numerical simulations of colloidal crystallization seeded by foreign objects. We perform Monte Carlo simulations to study how smooth spherical seeds of various sizes affect crystallization in a suspension of hard colloidal particles. We compute the free-energy barrier associated with crystal nucleation. A low barrier implies that nucleation is easy. We find that to be effective crystallization promoters, the seed particles need to exceed a well-defined minimum size. Just above this size, seed particles act as crystallization 'catalysts' as newly formed crystallites detach from the seed. In contrast, larger seed particles remain covered by the crystallites that they spawn. This phenomenon should be experimentally observable and can have important consequences for the control of the resulting crystal size distribution.
TL;DR: In this article, the growth kinetics of CdSe nanocrystals nucleated from TOPSe and cadmium oleate were investigated in octadecene, a non-coordinating solvent.
Abstract: The growth kinetics of CdSe nanocrystals nucleated from TOPSe and cadmium oleate were investigated in octadecene, a non-coordinating solvent. The effects of temperature and the oleic acid concentration on the kinetics of both nucleation and particle growth were investigated. It was found that increasing oleic acid concentrations led to smaller numbers of nuclei, smaller initial nuclei size, and larger final particle sizes. The rate constant for steady-state CdSe deposition was found to be 2.2 × 10-6 cm s-1 at ≈ 265 °C, far slower than the diffusion limit. The number of growing particles remained constant following the initial nucleation step. The radius of the primary CdSe nuclei varied from 1.0 ± 0.1 nm down to 0.8 ± 0.2 nm at lower oleic acid concentrations. Between 2 and 8% of the available Cd was consumed during nucleation. From the residual TOPSe and cadmium oleate concentrations at the onset of Ostwald ripening, the solubility of 2.2 nm CdSe in octadecene is measured to be 6.4 × 10-5 M2 at 265 °C. T...
TL;DR: The definition of appropriate order parameters that distinguish liquid from crystal, and on techniques to compute the kinetic prefactor that enters in the expression for the nucleation rate are focused on.
Abstract: Special computational techniques are required to compute absolute crystal nucleation rates of colloidal suspensions. Using crystal nucleation of hard-sphere colloids as an example, we describe in some detail the novel computational tools that are needed to perform such calculations. In particular, we focus on the definition of appropriate order parameters that distinguish liquid from crystal, and on techniques to compute the kinetic prefactor that enters in the expression for the nucleation rate. In addition, we discuss the relation between simulation results and theoretical predictions based on classical nucleation theory.
TL;DR: It is demonstrated that the nanocrystal nucleation and growth stages can be automatically separated in a homogeneous system with the presence of nucleation initiators.
Abstract: This paper reports a one-pot synthetic method for producing CdS nanocrystals. We have demonstrated that the nanocrystal nucleation and growth stages can be automatically separated in a homogeneous system with the presence of nucleation initiators. Accelerators used for more than 70 years in rubber vulcanization (i.e., tetraethylthiuram disulfides, and 2,2‘-dithiobisbenzothiazole) were found to be effective nucleation initiators for CdS nanocrystal synthesis. The as-prepared CdS nanocrystals are highly monodisperse and possess a zinc blende crystal structure. The quantum yield of the band-gap photoluminescence is up to 12% when the surface-trap emission was totally eliminated after a gentle oxidation under laboratory fluorescent light.
TL;DR: In this article, the optical and morphological properties of vanadium dioxide nanoparticles and thin films during their nucleation and growth phases have been studied by correlating the temperature and sharpness of the transition with the processing parameters.
Abstract: The optical and morphological characteristics of vanadium dioxide nanoparticles and thin films during their nucleation and growth phases have been studied by correlating the temperature and sharpness of the transition with the processing parameters. Thermal annealing results in grain growth and improved crystallinity. Normally, larger crystallites show smaller hysteresis, as there is a greater probability of finding a nucleating defect in the larger volume. But at the same time, this improved crystal perfection, which accompanies the thermal annealing and grain growth, tends to a larger hysteresis, as there are fewer nucleating defects within the volume. We show that the width and shape of the hysteresis cycle are thus determined by the competing effects of crystallinity and grain size.
TL;DR: In this paper, the photoluminescence properties of SiO2 nanoclusters were investigated by thermal annealing of SiOx films prepared by plasma enhanced chemical vapor deposition.
Abstract: Si nanoclusters embedded in SiO2 have been produced by thermal annealing of SiOx films prepared by plasma enhanced chemical vapor deposition. The structural properties of the system have been investigated by energy filtered transmission electron microscopy (EFTEM). EFTEM has evidenced the presence of a relevant contribution of amorphous nanostructures, not detectable by using the more conventional dark field transmission electron microscopy technique. By also taking into account this contribution, an accurate quantitative description of the evolution of the samples upon thermal annealing has been accomplished. In particular, the temperatures at which the nucleation of amorphous and crystalline Si nanoclusters starts have been determined. Furthermore, the nanocluster mean radius and density have been determined as a function of the annealing temperature. Finally, the optical and the structural properties of the system have been compared, to demonstrate that the photoluminescence properties of the system depend on both the amorphous and crystalline clusters.
TL;DR: In this paper, a small viscosity in the constitutive equations for the cohesive interface is introduced to avoid the post-instability behavior of crack initiation by using boundary value problems.
Abstract: Numerical simulations of crack initiation which use a cohesive zone law to model a weak interface in the solid are often limited by the occurrence of an elastic snap-back instability. At the point of instability, quasi-static finite element computations are unable to converge to an equilibrium solution, which usually terminates the calculation and makes it impossible to follow the post-instability behaviour. In this paper, we show that such numerical difficulties can easily be avoided by introducing a small viscosity in the constitutive equations for the cohesive interface. Simple boundary value problems are used to develop guidelines for selecting appropriate values of viscosity in numerical simulations involving crack nucleation and growth. As a representative application, we model crack nucleation at the interface between an elastic thin film and an elastic–plastic substrate, which is subjected to contact loading.
TL;DR: In this article, a mild urea hydrolysis based hydrothermal method through homogeneous nucleation at 413 K followed by calcination at 773 or 1173 K was used for nanoparticulate powders.
Abstract: Ce1-xZrxO2 (x = 0−0.8) nanoparticulate powders were prepared via a mild urea hydrolysis based hydrothermal method through homogeneous nucleation at 413 K followed by calcination at 773 or 1173 K. X...
TL;DR: The analysis shows nucleation on 50% of the study days and regional-scale formation of ultrafine particles on 30% of those days as discussed by the authors, and observed nucleation events ranged from weak events with only a slight increase in the particle number to relatively intense events with increases of total particle counts between 50,000 cm−3 up to 150,000cm−3.
Abstract: During the Pittsburgh Air Quality Study (PAQS) aerosol size distributions between 3 nm and 680 nm were measured between July 2001 and June 2002. These distributions have been analyzed to assess the importance of nucleation as a source of ultrafine particles in Pittsburgh and the surrounding areas. The analysis shows nucleation on 50% of the study days and regional-scale formation of ultrafine particles on 30% of the days. Nucleation occurred during all seasons, but it was most frequent in fall and spring and least frequent in winter. Regional nucleation was most common on sunny days with below average PM2.5 concentrations. Local nucleation events were usually associated with elevated SO2 concentrations. The observed nucleation events ranged from weak events with only a slight increase in the particle number to relatively intense events with increases of total particle counts between 50,000 cm−3 up to 150,000 cm−3. Averaging all days of the study, days with nucleation events had number concentrations peaki...
TL;DR: In this article, the authors measured the thermodynamics for the growth and evaporation of small cluster ions containing H2SO4 and H2O, and incorporated these data into a kinetic aerosol model to yield quantitative predictions of ion-induced nucleation for atmospheric conditions.
Abstract: [1] Field studies show that gas phase nucleation is an important source of new particles in the Earth's atmosphere. However, the mechanism of new particle formation is not known. The predictions of current atmospheric nucleation models are highly uncertain because the models are based on estimates for the thermodynamics of cluster growth. We have measured the thermodynamics for the growth and evaporation of small cluster ions containing H2SO4 and H2O, and incorporated these data into a kinetic aerosol model to yield quantitative predictions of the rate of ion-induced nucleation for atmospheric conditions. The model predicts that the binary negative ion H2SO4/H2O mechanism is an efficient source of new particles in the middle and upper troposphere. The ion-induced HSO4−/H2SO4/H2O mechanism does explain nucleation events observed in the remote middle troposphere, but does not generally predict the nucleation events observed in the boundary layer.
TL;DR: First experimental evidence is reported that thin islands of gold in fact have the same CO adsorption behavior as large gold particles and extended gold surfaces, and observed differences in reactivity of gold nanoparticles are proposed to arise from the presence of highly uncoordinated gold atoms.
Abstract: Size effects in adsorption and reactivity of supported metal particles have been observed for at least two decades. In recent years, gold nanoparticles have received attention for their extraordinary catalytic activity for reactions such as low temperature CO oxidation. A number of different theories have been advanced to explain this reactivity in terms of special reaction sites created by the metal–support interface. Goodman's group invoked quantum effects to explain a maximum in CO oxidation activity and suggested that particle thickness, in this case two atomic layers, may be the key parameter. Herein, through a combination of scanning tunneling microscopy (STM), temperature programmed desorption (TPD), and infrared reflection absorption spectroscopy (IRAS), we report the first experimental evidence that thin islands of gold in fact have the same CO adsorption behavior as large gold particles and extended gold surfaces. Therefore observed differences in reactivity of gold nanoparticles are proposed to arise from the presence of highly uncoordinated gold atoms. We have previously found that palladium exhibits twodimensional (2D) growth on a FeO(111) thin film, forming large monolayer islands, which display CO adsorption behavior that is different from bulk palladium. However, we have found in the case of gold that the transition from 2Dto 3D-growth occurs at a very low coverage ( 0.1 monolayers). Therefore, in the present work, we re-examine the situation at these low coverages to determine whether 2D gold structures also show deviations in CO adsorption behavior from the bulk. For coverage up to 0.1 : (effective thickness), gold forms islands of monolayer height (Figure 1a). The inset in Figure 1a shows that these monolayer islands are well shaped. At further increasing coverage the nucleation density remains fairly constant and two-layer particles form. Finally, at highest coverage studied ( 2 :), Au deposits of up to 7 nm in diameter and 4–5 layers in height are seen (Figure 1b). Note that unlike many other cases of nucleation and growth on oxide films the metal particles nucleate on regular sites of the FeO films. This implies that one may study the role of layer thickness independently of the influence of defects.
15 Nov 2004-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, a new model for the evolution of the precipitate structure derived by means of application of the thermodynamic extremum principle is presented, which describes the evolution the radii and of the chemical composition of individual precipitates of different phases in the multi-component system.
Abstract: A new model for the evolution of the precipitate structure derived by means of application of the thermodynamic extremum principle is presented. The model describes the evolution of the radii and of the chemical composition of individual precipitates of different phases in the multi-component system. In connection with a proper theory of nucleation, the model is able to describe the evolution of the precipitate structure in the classical stages of nucleation, growth and coarsening as well as interaction of precipitates of different phases, of different chemical composition and of different sizes via diffusion in the matrix.
TL;DR: In this paper, the least-action principle from the Wentzell-Freidlin theory of large deviations is exploited as a numerical tool for finding the optimal dynamical paths in spatially extended systems driven by a small noise.
Abstract: The least-action principle from the Wentzell-Freidlin theory of large deviations is exploited as a numerical tool for finding the optimal dynamical paths in spatially extended systems driven by a small noise. The action is discretized and a preconditioned BFGS method is used to optimize the discrete action. Applications are presented for thermally activated reversal in the Ginzburg-Landau model in one and two dimensions, and for noise-induced excursion events in the Brusselator taken as an example of a nongradient system arising in chemistry. In the Ginzburg-Landau model, the reversal proceeds via interesting nucleation events, followed by propagation of domain walls. The issue of nucleation versus propagation is discussed, and the scaling for the number of nucleation events as a function of the reversal time and other material parameters is computed. Good agreement is found with the numerical results. In the Brusselator, whose deterministic dynamics has a single stable equilibrium state, the presence of noise is shown to induce large excursions by which the system cycles out of this equilibrium state. c � 2004 Wiley Periodicals, Inc.
TL;DR: In this paper, the authors highlight recent research related to nucleation and growth of acicular ferrite during decomposition of austenite and highlight the possibility to maximize the content of acic ferrite by increasing the intragranular nucleation sites while maintaining a critical weld metal cooling rate and the steel hardenability.
Abstract: Research has shown that the acicular ferrite microstructure in steel weld metal, which provides an optimum combination of strength and toughness, is indeed intragranularly nucleated bainite. It is possible to maximize the content of acicular ferrite by increasing the intragranular nucleation sites while maintaining a critical weld metal cooling rate and the steel hardenability. This paper highlights recent research related to nucleation and growth of acicular ferrite during decomposition of austenite.
TL;DR: The results showed a very heterogeneous growth pattern, contradicting the classical assumption of smooth and spherical growth of new grains during recrystallization.
Abstract: We observed the in situ growth of a grain during recrystallization in the bulk of a deformed sample. We used the three-dimensional x-ray diffraction microscope located at the European Synchrotron Radiation Facility in Grenoble, France. The results showed a very heterogeneous growth pattern, contradicting the classical assumption of smooth and spherical growth of new grains during recrystallization. This type of in situ bulk measurement opens up the possibility of obtaining experimental data on scientific topics that before could only be analyzed theoretically on the basis of the statistical characterization of microstructures. For recrystallization, the in situ method includes direct measurements of nucleation and boundary migration through a deformed matrix.
TL;DR: In this article, the brittle-to-ductile transition in uniaxial tension was found to depend on poor interfacial adhesion between polymer and nanoparticle, which allows the nucleation of voids, typically by larger particles.
Abstract: Alumina/poly(methyl methacrylate) (PMMA) nanocomposites were synthesized using 38 and 17 nm alumina nanoparticles. At an optimum weight fraction, the resulting nanocomposites display a room-temperature brittle-to-ductile transition in uniaxial tension with an increase in the strain-to-failure that averages 40% strain and the appearance of a well-defined yield point in uniaxial tension. Concurrently, the glass transition temperature (Tg) of the nanocomposites drops by more than 20 °C. The brittle-to-ductile transition is found to depend on poor interfacial adhesion between polymer and nanoparticle. This allows the nucleation of voids, typically by larger particles (∼100 nm), which subsequently expand during loading. This void formation suppresses craze formation and promotes delocalized shear yielding. In addition, the reduction in Tg shrinks the shear yield envelope, further promoting this type of yield behavior. The brittle-to-ductile phenomenon is found to require both larger particles for void growth a...
TL;DR: A survey of bio-inspired approaches to artificial crystallization can be found in this paper, where the use of organized organic surfaces patterned with specific initiation domains on a submicrometer-scale to control patterned crystal growth is discussed.
Abstract: Nature produces a wide variety of exquite highly functional mineralized tissues using simple inorganic salts. Biomineralization occurs within specific microenvironments, and is finely tuned by cells and specialized biomacromolecules. This article surveys bio-inspired approches to artificial crystallization based on the above concept: that is, the use of organized organic surfaces patterned with specific initiation domains on a submicrometer-scale to control patterned crystal growth. Specially tailored self-assesbled monolayers (SAMs) of w-terminated alkanethils were micropatterned on metal films using soft lithography and applied as organic templates for the nucleation of calcium carbonate. Crystallization results in the formation of large-area, high-resolution inorganic replicas of the underlying crystallization process, including the precise localization of particles, nucleation density, crystal sizes, crystallographic orientation, morphology, polymorph, stability, and architecture. The ability to construct periodic arrays of uniform oriented single crystals, large single crystals with controlled microporosity, or films presenting patterns of crystals offers a potent methodology to materials engineering.