Ice nucleation in the atmosphere influences cloud properties, altering precipitation and radiative balance, ultimately regulating Earth’s climate. An accepted ice pathway, known as deposition nucleation, assumes a direct transition of water from vapor to phase, without an intermediate liquid phase. However, studies have shown that occurs through phase porous particles with narrow cracks or surface imperfections where condensation below saturation can occur, questioning validity nucleation....

Functionalized mesoporous silica offers promising possibilities for numerous applications, including drug delivery, catalysis, and adsorption. This minireview focuses on recent developments related to the postsynthetic positioning of functional groups silica. After briefly introducing reagents that are commonly used this purpose, methods control analyze distribution grafted discussed, with particular emphasis concepts allow placement at specific distances from each other, as well approaches...

Zeolites and mesoporous silica are versatile host materials for the supramolecular organization of a large variety guests. The inclusion luminescent molecules, complexes, or nanoclusters into ordered one-dimensional channel systems is particularly intriguing, as resulting host–guest compounds may exhibit unique properties such optical anisotropy, efficient energy transfer, enhanced stability. Several levels have been realized zeolite L, extending from interior given crystal to entrances...

In, out, shake it all about: The distribution of fluorescence-labeled amino groups on mesoporous silica was imaged by confocal laser scanning microscopy. mobility the aminosilane precursor determines degree external vs. pore-surface functionalization. This observation used to develop a simple and general method for modification surfaces.

We discuss artificial photonic antenna systems that are built by incorporating chromophores into one-dimensional nanochannel materials and organizing the latter in specific ways. Zeolite L (ZL) is an excellent host for supramolecular organization of different kinds molecules complexes. The range possibilities filling its channels with suitable guests has been shown to be much larger than one might expect. Geometrical constraints imposed structure lead channels. arrangement dyes inside ZL...

Abstract. It has recently been shown that pore condensation and freezing (PCF) is a mechanism responsible for ice formation under cirrus cloud conditions. PCF defined as the of liquid water in narrow capillaries below saturation due to inverse Kelvin effect, followed by either heterogeneous or homogeneous nucleation depending on temperature regime presence an ice-nucleating active site. By using sol–gel synthesized silica with well-defined diameters, morphology distinct chemical...

The growth of silica particles synthesized by the Stöber method was investigated co-condensation pyrene sulfonyl chloride (PySCl) coupled to (3-aminopropyl)triethoxysilane (APTES). Growth monomer addition could be distinguished from aggregation based on intensity excimer emission resulting particles. influence base concentration, water/ethanol ratio, solvent, temperature, and type precursor studied. At high hydrolysis rates, occurred primarily aggregation, whereas predominant at low rates....

Silver sulfide clusters are synthesized in the cavities of sodium and calcium zeolite A microcrystals by exposing activated Ag+-loaded to H2S. The growth silver during rehydration samples is investigated means diffuse reflectance spectroscopy. Monomers Ag2S formed at low Ag+-loading through reaction AgSH molecules, yielding colorless composites, which exhibit a characteristic blue-green photoluminescence. Yellow colored showing an orange-red luminescence with average decay time 81 μs (−160...

The effect of water on the reaction 3-aminopropyltriethoxysilane (APTES) with mesoporous silica is investigated two model systems. A MCM-41-type material a well-defined pore size used to investigate changes in distribution upon APTES toluene containing various amounts water. It found that, increasing amount water, clustering occurs, leading nonuniform grafted amino groups and scarcely functionalized body. second system defined particle morphology one-dimensional channels employed visualize...

The accessibility of amino groups in postsynthetically functionalized mesoporous silica MCM-41, MCM-48, and SBA-15 is investigated by reaction with fluorescein isothiocyanate (FITC). quantitative analysis the surface-grafted relation to amount coupled FITC over a wide range loadings affords information about potential pore blocking. In diameter domain 3−4 nm, actual size materials one-dimensional channel system (MCM-41) strongly affects coupling yield distribution anchored moieties. case...

We report discovery of a new efficient and robust antenna composite for light harvesting. The organic dye hostasol red (HR) is strongly luminescent in aprotic solvents but only weakly potassium zeolite L (ZL) at ambient conditions. observed dramatic increase the luminescence quantum yield HR–ZL composites if some or all exchangeable cations ZL are substituted by an imidazolium cation (IMZ+) acceptor HR embedded middle part channels, so that it fully protected environment perylene tb-DXP....

A combined experimental and modeling study of methylacridine (MeAcr(+)) dye-zeolite L composites unravels the microscopic origin their functional properties. The anisotropic orientation cationic dye inside ZL channel is unambiguously determined understood. most stable MeAcr(+), which features both its long short molecular axes nearly perpendicular to axis, mainly by dye-ZL electrostatic interactions but also depends on cosolvent water. In ZL, MeAcr(+) not hydrogen bonded water or framework...

The adsorption of simple gases begins with the formation a monolayer on pristine surface, not always followed by second or more monolayers. Subsequently, cluster cavity filling occurs, depending properties surface. characteristically different shape isotherms related to these processes allows clearly differentiate them. We analyzed argon and N2 quantitatively over entire relative pressure range for adsorbents bearing properties: nonporous Stöber-type particles, microporous zeolite L (ZL)...

The reaction of mesoporous silica MCM-41 with various aminopropylsilanes was investigated. distribution grafted amino groups after submonolayer deposition from anhydrous toluene probed by fluorescein labeling in conjunction photoluminescence spectroscopy and pore size analysis. Monoalkoxysilanes generally distributed more uniformly than monopodal dipodal trialkoxysilanes. outcome the grafting additionally depended on nature group. Secondary amines efficiently their primary analogues....

Abstract Sequential insertion of different dyes into the 1D channels zeolite L (ZL) leads to supramolecular sandwich structures and allows formation sophisticated antenna composites for light harvesting, transport, trapping. The synthesis properties dye molecules, host materials, composites, embedded in polymer matrices, including two‐ three‐color systems, are described. Perylene diimide (PDI) an important class chromophores great interest artificial systems. They especially well suited...

We report argon adsorption/desorption isotherms of MCM-41 and SBA-15. The shape all hysteresis loops we have observed corresponds to type H1. data been analyzed quantitatively using the multiple equilibria description applying notion metastable thermodynamic equilibrium. It is remarkable important that for both mesoporous materials desorption process can be understood according this but with a corresponding equilibrium constant. This procedure therefore allows determining values enthalpy...

The reaction of H2S with activated Ag+-loaded zeolite A leads to silver sulfide composites. optical absorption spectra samples different loading densities suggest the formation small clusters which are stable under ambient conditions. To our knowledge, this is first report on preparation and emission in cavities a size regime below 15 Å. investigated composites 0.05, 0.10, 0.25, 0.50, 1.00, 1.25, 1.50, 1.75, 2.00 ions per pseudo unit cell A. colorless (low density) or yellow-green (high...

Ru(III) and Ni(II) ammine complexes were grafted onto the pore surface of MCM-41 by ion exchange from basic aqueous solution. Covalent anchoring type M−O−Si (M = Ru or Ni) is obtained this method. The structure was studied UV−vis, FT-IR, X-ray absorption spectroscopy. [Ru(NH3)5Cl]2+ readily yielded monopodal grafting, while dehydration needed in case [Ru(NH3)6]3+ to achieve substitution a NH3 ligand with siloxy group. interaction charge-compensating groups remaining ligands further...

Electronic absorption and fluorescence spectra based on transmission measurements of thin layers obtained from new perylene–zeolite L composites dye1,dye2–zeolite sandwich composites, the latter acting as antenna systems, have been investigated analyzed. The influence extra- intraparticle self-absorption spectral shape quantum yield is discussed in detail. Due to its origin, re-emission can often not be avoided organized systems such dye–zeolite where a high density chromophores prerequisite...