Silica Clusters Research Articles

Physisorption of benzene on cation/silica clusters via cation-π interactions: Theoretical study

Interactions of a benzene molecule with four different silica clusters decorated with mono- and divalent cations (Li+, Na+, Mg2+) have been theoretically studied. By means of SAPT0 calculations, we have analyzed the changes in the energy components in dependence of hydrophobic or hydrophilic positions of adsorption, the size of the cluster studied or the cation used for the ’decoration’. It was found that adsorption of benzene on pristine silica clusters is mainly driven by electrostatic (∼37–43 %) and dispersion (∼37–55 %) forces. At the same time, cation-π interactions can be accounted for by significant electrostatic (∼20–50 %) and induction (∼24–54 %) energy terms. IGM analysis reveals the existence of cation-π and van der Waals interactions. The significant binding of benzene to the decorated silica surface (up to ∼ − 19.97, −29.63, − 93.82 kcal/mol for Na+, Li+, Mg2+, respectively) can pave a way for the sorption of a typical organic contaminant.

Silicate-lunar regolith composite: A vacuum self-hardened and comprehensively durable extraterrestrial construction material

Extraterrestrial exploration, represented by Lunar base construction, has been promoted worldwide as a multi-disciplinary, cutting-edge and strategic issue. Herein we proposed a novel extraterrestrial construction material composed of Lunar/Martian regolith simulants and only 4 wt% of silicate adhesive. This silicate-regolith composite can be directly self-hardened in vacuum within 4.5 h without any curing to achieve 29 MPa of hardening strength. Meanwhile, it shows comprehensive durability with stable microstructures and >70 % of residual strength against long-term vacuum exposure, huge temperature difference and intense γ-ray and proton radiations. Its in-situ solidification and durability originate from vacuum dehydration, where silica clusters in solution spontaneously cohere into a solid network with strong connections of silica tetrahedra and bound water. A moderate silicate modulus around 2.5 and appropriate modifications can disperse finer silica clusters to increase oligomer silica units in solution and enhance hardening strength. Compared with lunar geopolymer and other existing extraterrestrial construction materials, this vacuum self-hardening composite allows a cryogenic preparation even below −40 ℃ using diverse regolith with a wide range of compositions and sizes, proposing a facile, durable and versatile solution towards in-situ extraterrestrial constructions.

Plastic deformation and heat-enabled structural recovery of monolithic silica aerogels

Drying shrinkage during ambient pressure drying of silica gels is made reversible by preventing condensation reactions of surface silanol groups via surface modification. This partial recovery of the gel volume and structure is referred to as the spring-back effect (SBE) and enables the production of monolithic silica aerogels by evaporative drying. The SBE is sometimes completed by annealing at mild temperatures. Similarities between drying-related deformations and deformations induced by mechanical stimuli suggest analogous underlying mechanisms. While the causes of drying shrinkage are relatively well-known, it remains unclear how the relaxation of the structure by drying and annealing occurs across the different length scales. Here we show a complete structural recovery of silica aerogels at the macro- and nano-scale enabled by annealing. We propose that residual deformations after drying and mechanical compression are caused by the entanglement of silica clusters that can be unraveled by annealing at 230 °C. The deformation under loading is interpreted as two different re-arrangement mechanisms for dry and annealed gels, by the sliding of the silica clusters along the loading direction and by the compression of large pores beyond the fractal structure, respectively. Our results demonstrate how the shape and structure of silica aerogels can be restored and controlled by thermal activation, broadening the various applications of these materials. We also emphasize how tuning silica gels to promote a two-step SBE by annealing can pave the way toward the production of larger monolithic aerogels by APD.Graphical

Formation of Pre-PCTA/DT Intermediates from 2-Chlorothiophenol on Silica Clusters: A Quantum Mechanical Study.

Silica (SiO2), accounting for the main component of fly ash, plays a vital role in the heterogeneous formation of polychlorinated thianthrenes/dibenzothiophenes (PCTA/DTs) in high-temperature industrial processes. Silica clusters, as the basic units of silica, provide reasonable models to understand the general trends of complex surface reactions. Chlorothiophenols (CTPs) are the most crucial precursors for PCTA/DT formation. By employing density functional theory, this study examined the formation of 2-chlorothiophenolate from 2-CTP adsorbed on the dehydrated silica cluster ((SiO2)3) and the hydroxylated silica cluster ((SiO2)3O2H4). Additionally, this study investigated the formation of pre-PCTA/DTs, the crucial intermediates involved in PCTA/DT formation, from the coupling of two adsorbed 2-chlorothiophenolates via the Langmuir-Hinshelwood (L-H) mechanism and the coupling of adsorbed 2-chlorothiophenolate with gas-phase 2-CTP via the Eley-Rideal (E-R) mechanism on silica clusters. Moreover, the rate constants for the main elementary steps were calculated over the temperature range of 600-1200 K. Our study demonstrates that the 2-CTP is more likely to adsorb on the termination of the dehydrated silica cluster, which exhibits more effective catalysis in the formation of 2-chlorothiophenolate compared with the hydroxylated silica cluster. Moreover, the E-R mechanism mainly contributes to the formation of pre-PCTAs, whereas the L-H mechanism is prone to the formation of pre-PCDTs on dehydrated and hydroxylated silica clusters. Silica can act as a relatively mild catalyst in facilitating the heterogeneous formation of pre-PCTA/DTs from 2-CTP. This research provides new insights into the surface-mediated generation of PCTA/DTs, further providing theoretical foundations to reduce dioxin emission and establish dioxin control strategies.

Synergistic effect of silica/polypyrrole nanocomposites synthesized by hydrothermal method using rice husk as a silica source for corrosion protection

Rice husk, a plentiful agricultural waste, is a natural and environmentally friendly silica reservoir. In this study, a hydrothermal synthesis was employed to produce silica/polypyrrole nanocomposites, with the primary objective of developing corrosion-resistant materials. The nanocomposites are comprehensively characterized using XRD, FTIR, FESEM, and electrochemical studies. The results confirmed the successful formation of a silica/polypyrrole nanocomposite and revealed that the adsorption of polypyrrole molecules onto silica clusters controls the formation of larger silica nanoparticles. Pure silica exhibits spherical particles ranging from 500 to 1 μm. A low concentration of polypyrrole results in nanoparticles with dimensions ranging from 100 to 200 nm, while a higher concentration leads to reduced silica nanoparticles with sizes 10–20 nm. Aggregation of spherical nanoparticles is more prominent in silica/polypyrrole nanocomposites than pure silica nanoparticles. The nanocomposites of silica/polypyrrole, namely SP-1, SP-2, and SP-3, demonstrated significantly higher corrosion resistance (Rct) values of 36613 Ω, 44536 Ω, and 49060 Ω, respectively, in comparison to the pure silica (19540 Ω). The corrosion rates of pure silica, SP-1, SP-2, and SP-3 were determined to be 1.2687 mm/yr, 0.4715 mm/yr, 0.4681 mm/yr, and 0.3042 mm/yr, respectively. Silica exhibits remarkable chemical stability and exceptional corrosion resistance, whereas polypyrrole is a conducting polymer endowed with distinctive electrical characteristics. These constituents can be synergistically combined within a nanocomposite matrix, enhancing corrosion resistance. The synthesized nanocomposite exhibits considerable promise as a corrosion-resistant coating agent, presenting a sustainable remedy for corrosion mitigation in different industrial contexts.

Utilizing Gelatin Waste for Efficient Bimodal Porous Silica Adsorbents for Carbon Dioxide Capture.

This study explores the modification of pore structures in porous silica materials synthesized using sodium silicate and waste gelatin, under varying silica-to-gelatin ratios. At ratios of 1.0-1.5, bimodal porous silica with mesopores and macropores emerged due to spaces between silica nanoparticles and clusters, following gelatin elimination. The study further evaluated the obtained bimodal porous silica as polyethyleneimine (PEI) supports for CO2 capture, alongside PEI-loaded unimodal porous silica and hollow silica sphere for comparison. Notably, the PEI-loaded bimodal silica showcased superior CO2 uptake, achieving 145.6 mg g-1 at 90 °C. Transmission electron microscopy (TEM) revealed PEI's uniform distribution within the pores of bimodal silica, unlike the excessive surface layering seen in unimodal silica. Conversely, PEI completely filled the hollow porous silica's interior, extending gas molecule diffusion distance. All sorbents displayed nearly constant CO2 adsorption across 20 cycles, demonstrating outstanding stability. Notably, the bimodal porous silica displayed a negligible capacity loss, underscoring its robust performance.

Plasma Polymerization of Precipitated Silica for Tire Application.

Pre-treated silica with a plasma-deposited (PD) layer of polymerized precursors was tested concerning its compatibility with Natural Rubber (NR) and its influence on the processing of silica-silane compounds. The modification was performed in a tailor-made plasma reactor. The degree of deposition of the plasma-coated samples was analyzed by ThermoGravimetric Analysis (TGA). In addition, Diffuse Reflectance Infrared Fourier Transform spectroscopy (DRIFTs), X-ray Photoelectron Spectroscopy (XPS), and Transmission Electron Microscopy (TEM) were performed to identify the morphology of the deposited plasma polymer layer on the silica surface. PD silica samples were incorporated into a NR/silica model compound. NR compounds containing untreated silica and in-situ silane-modified silica were taken as references. The silane coupling agent used for the reference compounds was bis-(3-triethoxysilyl-propyl)disulfide (TESPD), and reference compounds with untreated silica having the full amount and 50% of silane were prepared. In addition, 50% of the silane was added to the PD silica-filled compounds in order to verify the hypothesis that additional silane coupling agents can react with silanol groups stemming from the breakdown of the silica clusters during mixing. The acetylene PD silica with 50% reduced silane-filled compounds presented comparable properties to the in-situ silane-modified reference compound containing 100% TESPD. This facilitates processing as lower amounts of volatile organic compounds, such as ethanol, are generated compared to the conventional silica-silane filler systems.

Surface modification of Fe5C2 by binding silica-based ligand: A theoretical explanation of enhanced C2 oxygenate selectivity

Elucidating the role(s) of support-like ligands remains a challenge in catalytic reaction like the Fischer-Tropsch Synthesis (FTS) catalyzed by the iron catalyst supported on silica. We herein theoretically investigated surface modification of Fe5C2 by silica-based ligand and its influence on C2 oxygenate selectivity in FTS, by carrying out DFT calculations on dissociation of CO and formations of CH4 and C2 on ha-SiO2/Fe5C2(510). To mimic the structure of surface modification, the ha-SiO2/Fe5C2(510) model was built up by binding the silica cluster (the ha-SiO2 ligand) to Fe5C2(510). DFT calculations elucidated that the C + CH coupling with the lowest activation barrier among all the possible routes of C2 formation on Fe5C2(510) is suppressed after modification with the ha-SiO2 ligand because the binding ha-SiO2 ligand limits the geometry relaxation caused by the C+CH coupling. However, CO molecule is anchored by the ha-SiO2 ligand via hydrogen bond, suppressing the CO cleavage because the d-valence band center of Fe5C2(510) lowers in energy by surface modification with the ha-SiO2 ligand, but facilitating the C + CO coupling with the lowest activation barrier among all the possible routes of C2 formation. Also, CH4 formation in the ha-SiO2/Fe5C2(510) case is not so easy as that on Fe5C2(510). Therefore, C2 oxygenate is formed more easily in the ha-SiO2/Fe5C2(510) case than in the Fe5C2(510) case. The result agrees with the experimental observation that C2 oxygenate selectivity became high for iron-based FTS catalyst after surface modification of by silica-based ligand.

Investigating the viscoelastic and hysteresis behavior of nano silica/carbon black hybrid reinforced styrene‐butadiene rubber vulcanizates via surface silanization

AbstractWith the thought of green tires and the need of replacing carbon reinforcing fillers with noncarbon silica filler, the effectiveness of silane surface modification on dispersion state, dynamic viscoelastic, hysteresis, and abrasion resistance of SBR vulcanizates filled with a hybrid of carbon black (CB)/nano SiO2 is investigated. In situ surface modification of nano SiO2 is carried out using bis‐(γ‐triethoxysilylpropyl)‐tetrasulfide (TESPT), and various compounds with different ratios of CB/SiO2 are prepared via a melt mixing process in an internal bath mixer. Scanning electron microscopy (SEM) and FT‐IR spectroscopy revealed improved dispersion of silica and CB clusters with enhanced molecular interactions using in situ surface modification with 5 phr of TESPT is performed. Evidence for enhanced molecular interactions included lower dynamic loss (tanδ) and less hysteresis measured via dynamic mechanical thermal analysis (DMTA). Our results indicate that appropriate modification of silica allows partial replacement of carbon black with silica for production of eco‐friendly rubber products.

Protonation Process of Porous Silica Cluster Surface using Molecular Dynamics Method

Using molecular dynamic simulation, we developed an algorithm to protonate the surface of an amorphous porous silica grain particle model and study its effect. In this work, the silica grain model can be used to study cosmic dust coagulation. The surface of the silica cluster was protonated by placing H atoms on oxygen atoms having only a single bond, namely, the non-bridging oxygens. The H atoms are placed opposite the Si–O bond with a distance of around 1 Å to form silanol (Si–O–H) group termination on the silica surface. The angular conformation of the silanol was optimized by relaxing the surface at low temperature. We evaluated the number of silanol groups, the angular distribution of the Si-O-H bond, and the average distance between Si-O particles using the radial distribution function (RDF). The result of the study shows that minimizing the energy of the silica surface changes the angular distribution of the silanol from 180° to about 110° and between 140°-160°. However, the average distance between Si-O particles remains at 1 Å, which demonstrates the correctness of the atomic interaction model. The addition of protons on the silica surface is an essential factor in the simulation of cosmic dust collision since the modification of the surface chemistry may alter the contact surface energy, thus changing the probability of particle coagulation.

Characterization of polar surface groups on siliceous materials by inverse gas chromatography and the enthalpy-entropy compensation effect.

Surface-modified porous silica is a well-established composite material. To improve its embedding and application behavior, adsorption studies of various probe molecules have been performed using the technique of inverse gas chromatography (IGC). For this purpose, IGC experiments were carried out in the infinite dilution mode on macro-porous micro glass spheres before and after surface modification with (3-mercaptopropyl)trimethoxysilane. To provide information about the polar interactions between probe molecules and the silica surface, in particular, eleven polar molecules have been injected. In summary, the free surface energy for pristine silica ( = 229mJ/m2) and for (3-mercaptopropyl)trimethoxysilane-modified silica ( = 135mJ/m2) indicates a reduced wettability after surface modification. This is due to the reduction of the polar component of the free surface energy ( ) from 191mJ/m2 to 105mJ/m2. Simultaneously, with the reduction of surface silanol groups caused by surface modification of silica and, therefore, the decrease in polar interactions, a substantial loss of Lewis acidity was observed by various IGC approaches. Experiments with all silica materials have been conducted at temperatures in the range from 90°C to 120°C to determine the thermodynamic parameters, such as adsorption enthalpy ( ) and adsorption entropy ( ), using the Arrhenius regression procedure evaluating the IGC data. With the help of the enthalpy-entropy compensation, two types of adsorption complexes are assumed between polar probe molecules and the silica surface because of different isokinetic temperatures. Identical adsorption complexes with an isokinetic temperature of 370°C have been assigned to alkanes and weakly interacting polar probes such as benzene, toluene, dichloromethane, and chloroform. Polar probe molecules with typical functional groups such as OH, CO, and CN, having the ability to form hydrogen bonds to the silica surface, exhibit a lower isokinetic temperature of 60°C. Quantum chemical calculations of the probe molecules on a non-hydroxylated and hydroxylated silica cluster supported the formation of hydrogen bonds in the case of a strong polar adsorption complex with a bonding distance of 1.7nm-1.9nm to the silica surface.

The location of the chemical bond. Application of long covalent bond theory to the structure of silica.

Oxygen is the most abundant terrestrial element and is found in a variety of materials, but still wanting is a universal theory for the stability and structural organization it confers. Herein, a computational molecular orbital analysis elucidates the structure, stability, and cooperative bonding of α-quartz silica (SiO2). Despite geminal oxygen-oxygen distances of 2.61-2.64Å, silica model complexes exhibit anomalously large O-O bond orders (Mulliken, Wiberg, Mayer) that increase with increasing cluster size-as the silicon-oxygen bond orders decrease. The average O-O bond order in bulk silica computes to 0.47 while that for Si-O computes to 0.64. Thereby, for each silicate tetrahedron, the six O-O bonds employ 52% (5.61 electrons) of the valence electrons, while the four Si-O bonds employ 48% (5.12 electrons), rendering the O-O bond the most abundant bond in the Earth's crust. The isodesmic deconstruction of silica clusters reveals cooperative O-O bonding with an O-O bond dissociation energy of 4.4kcal/mol. These unorthodox, long covalent bonds are rationalized by an excess of O 2p-O 2p bonding versus anti-bonding interactions within the valence molecular orbitals of the SiO4 unit (48 vs. 24) and the Si6O6 ring (90 vs. 18). Within quartz silica, oxygen 2p orbitals contort and organize to avoid molecular orbital nodes, inducing the chirality of silica and resulting in Möbius aromatic Si6O6 rings, the most prevalent form of aromaticity on Earth. This long covalent bond theory (LCBT) relocates one-third of Earth's valence electrons and indicates that non-canonical O-O bonds play a subtle, but crucial role in the structure and stability of Earth's most abundant material.

Anisotropic flocculation in shear thickening colloid-polymer suspension via simultaneous observation of rheology and X-ray scattering

A shear thickening fluid, showing a significant increase in viscosity under shear stress, is a promising material for shock absorption applications. Colloidal dispersions of silica nanoparticles and polyethylene oxide polymers with large molecular weights also exhibit a shear thickening phenomenon, which is manifested by a transformation from liquid to gel, called shake-gel. To understand the gelation mechanism, small-angle X-ray scattering (SAXS) and ultra-small-angle X-ray scattering (USAXS) were performed with an X-ray transmission cell, which was used as a Couette cell in a rheometer. This setup enables simultaneous rheological measurements with SAXS and USAXS, providing real-time observation of the change from liquid to gel. An anisotropic increase of the scattering spectra indicated the formation of aligned floc structures. This result implies that a polymer chain recombined the network and transformed into the large flocs aligned in the flow direction. Additionally, the shifted peaks from the silica cluster indicated that the aligned flocs were compressed by the shear stress. The present work paves the way for the advanced design of shake-gel materials.

The effect of enclosed water–ice pockets on porous silica cluster collisions

Collisions between dust particles play an important role in the initial stages of the formation of rocky planets. In space, silica dust exhibits a porous structure due to its formation history. Outside the ice line, water–ice will be present on and in silica dust particles, such that collisions between water-ice-filled porous silica grains are relevant. Molecular dynamics simulations are used to simulate central collisions of such grains (diameter 44 nm), focusing on the analysis of bouncing events. While naked bulk silica particles bounce at high velocities, empty porous silica particles always stick since plastic deformation of the porous structure adds to energy dissipation during the collision. Ice-filled porous silica particles exhibit bouncing collisions already at smaller velocities than naked bulk silica particles of the same size. Collision-induced heating of the ice in the collision zone and also in the pores assists the bouncing process. The coefficient of restitution shows good agreement with available macroscopic models, if both the bouncing velocity and the energy dissipation during the collision are used as fitting parameters. Our results give insights into the agglomeration and bouncing of heterogeneous silica–ice particles, relevant for energetic collision processes outside of the ice line in protoplanetary and planetary systems.

Fe2O3-decorated hollow porous silica spheres assisted by waste gelatin template for efficient purification of synthetic wastewater containing As(V)

Purification of As(V)-contaminated water through adsorption by Fe2O3-based materials is a promising technology due to its low-cost and high efficiency. Dispersing the Fe2O3 phase on silica supports can improve both the adsorption rate and capacity due to the reduction in Fe2O3 particle sizes and the prevention of clumping of the Fe2O3 particles. However, the clusters in conventional silica materials largely impede the diffusion of As(V) to reach the Fe2O3 sites dispersed inside the clusters. Here, by applying a gelatin template strategy, the structure of silica materials was tailored by changing the gelatin-to-silica ratio (0, 0.6, 1.2 and 1.8) and hydrothermal temperature (60 °C, 100 °C and 140 °C). The silica cluster size could be reduced using either a low gelatin-to-silica ratio (0.6) or a low hydrothermal temperature (60 °C). Increasing the gelatin-to-silica ratio to 1.2 created porous silica spheres with a hollow structure. The Fe2O3-loaded hollow porous silica spheres with a shell thickness of 280 nm had twice the maximum As(V) adsorption capacity (7.66 mg g−1) compared to the Fe2O3-loaded silica product prepared in the absence of gelatin (3.82 mg g−1). The maximum As(V) adsorption capacity could be further enhanced to 9.94 mg g−1 by reducing the shell thickness to 80 nm through increasing the gelatin-to-silica ratio to 1.8 and the hydrothermal temperature to 140 °C. In addition, the best Fe2O3-loaded hollow porous silica spheres had rapid As(V) adsorption and showed excellent durability as the As(V) removal efficiency slightly decreased to 98.9% subsequent to five adsorption-regeneration cycles.

Hydrothermal synthesis temperature induces sponge-like loose silica structure: A potential support for Fe2O3-based adsorbent in treating As(V)-contaminated water

Low cost Fe2O3-based sorbents with an exceptional selectivity toward the targeted As(V) pollutant have gained extensive attention in water treatment. However, their structural features often influence removal performance. In this respect, we present herein a rational design of silica-supported Fe2O3 sorbents with an enhanced morphological structure based on a simple temperature-induced process. Low-hydrothermal temperature synthesis (60 and 100 °C) provided a large silica-cluster size with a close packed structure (S-60 and S-100), contributing to an increase in mass transport resistance. Fe2O3/S-60 with 6.2-nm pore width silica achieved a maximum As(V) uptake capacity (qm) of only 3.5 mg g−1. Supporting Fe2O3 on S-100 with an approximately two-fold increase in the pore size (13 nm) did not lead to any evident enhancement in qe (3.7 mg g−1). However, expanding the pore window up to 22.6 nm (S-140) and 39.5 nm (S-180), along with changing from close-packed to sponge-like loose structures induced by high-temperature synthesis (140 °C and 180 °C), resulted in substantial increases in qm. Fe2O3/S-140 had 1.7 and 1.6 times higher qm (5.9 mg g−1) than Fe2O3/S-100 and Fe2O3/S-60, respectively. The highest qm (7.4 mg g−1) was achieved for Fe2O3/S-180, which was attributed to its relatively small-sized silica cluster and the largest cavities that facilitated easier access by As(V) to adsorbing sites.

Thermophoretic levitation of solid particles at atmospheric pressure

Separation and transportation of powders are important processes in various technological applications. Although mechanical, chemical, or electrical methods can provide possible solutions, operational or environmental constraints may require alternative methods. Spreading and levitation of clusters (aggregates) of fluorinated fumed silica nanoparticles placed under atmospheric pressure on a hot plate is reported. The powder spreading in the chamber continued until the temperature-dependent saturation value of the spot radius, which grew linearly with the temperature. Open space experiments clearly demonstrated levitation of the powder clouds. Qualitative physical analysis of the observed phenomena is suggested. The effect of levitation is explained by the lifting thermo-phoretic force emerging in the Knudsen layer of air. The levitation of the powder under atmospheric pressure becomes possible due to the combination of low adhesion of the fluorinated fumed silica clusters to the substrate, low density of the particles and clusters, and their high specific surface area.

DNA Origami-Encoded Integration of Heterostructures.

Integrating dissimilar materials at the nanoscale is crucial for modern electronics and optoelectronics. The structural DNA nanotechnology provides a universal platform for precision assembly of materials; nevertheless, heterogeneous integration of dissimilar materials with DNA nanostructures has yet to be explored. We report a DNA origami-encoded strategy for integrating silica-metal heterostructures. Theoretical and experimental studies reveal distinctive mechanisms for the binding and aggregation of silica and metal clusters on protruding double-stranded DNA (dsDNA) strands that are prescribed on the DNA origami template. In particular, the binding energy differences of silica/metal clusters and DNA molecules underlies the accessibilities of dissimilar material areas on DNA origami. By programming the densities and lengths of protruding dsDNA strands on DNA origami, silica and metal materials can be independently deposited at their predefined areas with a high vertical precision of 2 nm. We demonstrate the integration of silica-gold and silica-silver heterostructures with high site addressability. This DNA nanotechnology-based strategy is thus applicable for integrating various types of dissimilar materials, which opens up new routes to bottom-up electronics.

DNA Origami‐Encoded Integration of Heterostructures

AbstractIntegrating dissimilar materials at the nanoscale is crucial for modern electronics and optoelectronics. The structural DNA nanotechnology provides a universal platform for precision assembly of materials; nevertheless, heterogeneous integration of dissimilar materials with DNA nanostructures has yet to be explored. We report a DNA origami‐encoded strategy for integrating silica‐metal heterostructures. Theoretical and experimental studies reveal distinctive mechanisms for the binding and aggregation of silica and metal clusters on protruding double‐stranded DNA (dsDNA) strands that are prescribed on the DNA origami template. In particular, the binding energy differences of silica/metal clusters and DNA molecules underlies the accessibilities of dissimilar material areas on DNA origami. By programming the densities and lengths of protruding dsDNA strands on DNA origami, silica and metal materials can be independently deposited at their predefined areas with a high vertical precision of 2 nm. We demonstrate the integration of silica‐gold and silica‐silver heterostructures with high site addressability. This DNA nanotechnology‐based strategy is thus applicable for integrating various types of dissimilar materials, which opens up new routes to bottom‐up electronics.

In English

The model sizes of solid particles as well as used quantum chemical methods can affect results of calculations with density functional theory (DFT) methods. The aim of this study was to analyze the effects of the silica cluster sizes, a number of bound water molecules, protonation and deprotonation of silanols, addition of Eigen cation alone or solvated, attachment of anions F- and Cl- alone or solvated, and whole solvation effects (with SMD) with the DFT calculations using a functional ωB97X-D with the cc-pVDZ basis set. The calculations of the distribution functions of atom charges (CDF), chemical shifts of the proton resonance (SDF), and integral density of electron states (IDES) show that small clusters with 8 or 22 (SiO4/2) units could give rather inappropriate results in contrast to larger clusters with 44 or 88 units. This is due to the fact that the small silica clusters do not have appropriate capability for delocalization of excess charges that leads to certain distortion of the electron states of the whole system. The IDES are more sensitive with respect to the cluster charging and less sensitive to the solvation effects than the CDF and SDF. As a whole, the use of several types of the distribution functions, such as integral characteristics with the CDF, SDF, and IDES, allows one to obtain a more detailed picture on the interfacial phenomena at silica surface for neutral and charged systems.