Tubular Pores Research Articles

Thermally-Conductive-Pin Patterned Substrate: Innovative Strategy for Controlled Formation of Tubular Pores in Biodegradable Polymer Membranes

Thermally-Conductive-Pin Patterned Substrate: Innovative Strategy for Controlled Formation of Tubular Pores in Biodegradable Polymer Membranes

Soil Biopores and Non-Biopores Responses to Different Tillage Treatments in Sugarcane Fields in Guangxi, China

Different types of soil macropores respond differently to various tillage practices, owing to disparities in origin, scale, morphology, and function, consequently exerting distinct effects on soil structure. This study aimed to investigate the response mechanisms of three different soil pore types (total macropores, non-biopores, and biopores) to two distinct tillage practices: smash-ridging tillage (T) and no-tillage (NT) in sugarcane fields. The parameters characterizing soil pore treatments in two and three dimensions were obtained using X-ray computed tomography scanning technology. ImageJ and MATLAB software were employed to analyze the data and separate soil macropores into biopores and non-biopores categories. The results showed that non-biopores predominated in two-dimensional cross-sectional areas in NT treatment, whereas biopores were more dominant in T treatment. Biopores in T treatment had a higher proportion of two-dimensional pores compared to NT treatment. A three-dimensional analysis indicated that total macropores had larger mean diameters (MD) and macroporosity, with more continuous tubular pores in T treatment than that in NT treatment. However, NT treatment had more numerous non-biopores with broader spatial distribution and complex morphology. Additionally, biopores in T treatment had larger MD and branching length density (LD). These vertically developed biopores, along with high macropore connectivity and under smash-ridging tillage, could improve soil water and pore conductivity. Therefore, smash-ridging tillage was more beneficial for sugarcane growth compared to no-tillage in Guangxi of China.

Preparation of Alumina Membrane Filters with Framework Structures by Al Anodization.

Alumina membrane filters consisting of a thin filter layer (200-700 nm in thickness) supported by a framework (30-100 μm in thickness) were fabricated on the basis of the anodization of an Al substrate. The solution permeability of alumina membrane filters with tubular pores of uniform size and shape varies with membrane thickness; therefore, membrane filters with a filter layer thickness of less than 1 μm showed high solution permeability. Although the filter layer is thin, it is reinforced by a thick framework, enabling the fabrication of large freestanding membrane filters (2.5 × 2 cm2 in size). The pore size of the anodic porous alumina formed by the anodization of Al can be controlled in the range from 10 nm to ca. 2 μm by varying the preparation conditions. The alumina membrane obtained by this method is therefore useful as a membrane filter that can efficiently separate particles of various sizes, including microplastics, viruses, and bacteria. This method enables the fabrication of membrane filters with uniform pore size, high solution permeability, and sufficient mechanical strength for handling as freestanding membranes, which have been difficult to achieve with the reported preparation processes for membrane filters. The obtained membrane filters with frameworks can be applied to efficient microfiltration.

Water transport through mesoporous amorphous-carbon dust

The diffusion of water molecules through mesoporous dust of amorphous carbon (a-C) is a key process in the evolution of prestellar, protostellar, and protoplanetary dust, as well as in that of comets. It also plays a role in the formation of planets. Given the absence of data on this process, we experimentally studied the isothermal diffusion of water molecules desorbing from water ice buried at the bottom of a mesoporous layer of aggregated a-C nanoparticles, a material analogous to protostellar and cometary dust. We used infrared spectroscopy to monitor diffusion in low temperature (160 to 170 K) and pressure (6 × 10−5 to 8 × 10−4 Pa) conditions. Fick’s first law of diffusion allowed us to derive diffusivity values on the order of 10−2 cm2 s−1, which we linked to Knudsen diffusion. Water vapor molecular fluxes ranged from 5 × 1012 to 3 × 1014 cm−2 s−1 for thicknesses of the ice-free porous layer ranging from 60 to 1900 nm. Assimilating the layers of nanoparticles to assemblies of spheres, we attributed to this cosmic dust analog of porosity 0.80−0.90 a geometry correction factor, similar to the tortuosity factor of tubular pore systems, between 0.94 and 2.85. Applying the method to ices and refractory particles of other compositions will provides us with other useful data.

Towards nanomaterials with tubular pores: synthesis and self-assembly of bis-pillar[5]arene

Recently, materials obtained using supramolecular chemistry approaches, and, in particular, spatially preorganized macrocyclic compounds, have attracted close attention of the researchers. Pillar[n]arenes are of special interest due to their tubular spatial structure and macrocyclic cavity. A similar tubular structure is retained in the supramolecular packaging of pillar[5]arene crystals, forming pores. In this study, we developed a block synthetic approach for the preparation of bis-pillar[5]arene containing amide groups. The ability of the synthesized bis-pillar[5]arene to form stable self-associates in solvents of different polarity (CHCl3 and CH3OH) was demonstrated by the DLS method. In trichloromethane at concentration of 1·10–3 M, monodisperse associates with average hydrodynamic diameter of 227 nm (PDI = 0.28) are formed; in methanol, stable associates (1·10–6 M) have an average hydrodynamic diameter of 136 nm (PDI = 0.21). The results obtained can be used to create new supramolecular systems, molecular machines, or capture and detect various organic molecules.

Impacts of the soil pore structure on infiltration characteristics at the profile scale in the red soil region

The complexity and uncertainty of pore structures, hinder the understanding of the water infiltration process along a soil profile. In this study, soil pore structures quantified by X-ray computed tomography (CT) scanning and infiltration processes traced using stable hydrogen and oxygen isotopes were linked under three land uses (forestland, citrus land, and rainfed cropland) in the red soil region of southern China. Our results showed that 95% of the soil pore diameters in the surface layer (0–20 cm) in forestland, citrus land, and rainfed cropland were concentrated in the ranges of 0.05–2.46, 0.05–2.24 and 0.05–1.04 mm, respectively. Rainfed cropland had the most soil micropores, along with a high porosity and poor connectivity, while there were more large, well-connected tubular pore channels in the forestland and citrus land. Hydrogen and oxygen stable isotopes were effective in tracing soil water infiltration processes under saturated and near-saturated conditions. The soil infiltration depths of citrus land, forestland, and rainfed cropland were 45, 40, and 25 cm, with "new water" volumes of 37.2, 26.4, and 22.3 mm, respectively. CT-based porosity and the soil texture were considered crucial indicators in the evaluation of the exchange between “old water” and “new water” during infiltration processes. More specifically, the soil structure of the limiting layer not only controlled the infiltration rate but also played an extremely important role in the infiltration mechanism, reflected by the different ratios of “new water”. The soil pore characteristics mainly affected soil water transport, while other soil properties played more important roles in soil water retention.

3D-dimensional Effective Stress Analysis of Wetting and Wetting Trapping Process in Wet-submerged Loess Tunnel Surrounding Rock Based on BP Neural Network

INTRODUCTION: China's loess is vast. Loess has apparent high strength and resistance to deformation once encountered with water immersion and humidification, fusible salts precipitated on the surface of soil particles, the soil's carry alkalization strength is relatively reduced, while the vertical tubular pores in the soil accelerate the infiltration of water, the earth will be in the self-weight or the overlying loads of the additional action of the soil body will produce a significant settlement deformation, which results in the structural damage of the upper building, which is the loss of the wetting of subsidence.
 OBJECTIVES: From China's practical point of view, the humidification and wetting process of wetted loess tunnel peripheral rock is deeply discussed and analyzed, and the water content distribution characteristics of wetted loess tunnel peripheral rock are sought.
 METHODS: Using the particle swarm algorithm, four neural optimization network models, namely, radial basis neural network (RBFNN), generalized regression neural network (GRNN), wavelet neural network (WNN), and fuzzy neural network (FNN), are simulated and created for the analysis of three-dimensional effective stresses in the process of humidity and wetness subsidence in the surrounding rock of loess tunnels of a northwestern city in China and a central city in China.
 RESULTS: By analyzing the comparison graphs between the predicted and actual values of these four models on the test data of two sets of experimental data, the distribution of the proportion of the expected difference to the true value, and the results of the calculation of the three error indexes, it can be found that when using the four neural networks, namely, RBFNN, GRNN, WNN, and FNN, for the analysis of the three-dimensional effective stresses during the process of increasing wetting and wetting of the surrounding rock of the tunnel in the soil-wetted loess, the prediction performance of the WNN is the best.
 CONCLUSION: The soil's unsaturated settlement characteristics differ for different water contents and humidification times. The shorter the period, the more the soil column water content difference. With the continuous increase of water content change in the soil layer, the distribution of water content change in the loess soil column tends to be relatively uniform, and the difference in damage rate between the upper and lower layers tends to be reduced—the amount, time, and pressure of humidification controls wet subsidence.

Cucurbituril-Shaped Cd18(triazolate)12 Unit-Based Metal-Organic Framework Exhibiting an C2H2/CO2 Separation Ability.

Herein, a metal-organic framework (MOF), {[(Me2NH2)4][Cd(H2O)6][Cd18(TrZ)12(TPD)15(DMF)6]}n (denoted as JXNU-18, TrZ = triazolate), constructed from the unique cucurbituril-shaped Cd18(TrZ)12 secondary building units bridged by 2,5-thiophenedicarboxylic (TPD2-) ligands, is presented. The formation of the cucurbituril-shaped Cd18(TrZ)12 unit is unprecedented, demonstrating the geometric compatibility of the organic linkers and the coordination configurations of the cadmium atoms. Each Cd18(TrZ)12 unit is connected to eight neighboring Cd18(TrZ)12 units through 30 TPD2- linkers, affording the three-dimensional structure of JXNU-18. More interesting is that JXNU-18 displays an efficient C2H2/CO2 separation ability, as revealed by the gas adsorption experiments and dynamic gas breakthrough experiments, which afford insights into the potential applications of JXNU-18 in gas separation. The tubular pores composed of two Cd18(TrZ)12 units bridged by six 2,5-thiophenedicarboxylic linkers provide the suitable pore space for C2H2 trapping, as unveiled by computational simulations.

Copper–zinc/chitosan complex hydrogels: Rheological, degradation and biological properties

Polymer hydrogels crosslinked by therapeutic metal ions have attracted increased interest in recent years due to their unique and versatile properties. Chitosan hydrogels are widely investigated for various biomedical applications such as tissue engineering and drug delivery. Copper and zinc ions are considered as therapeutic metal ions, that have important roles in bone regeneration. The aim of this study was to investigate the physicochemical and biological properties of bimetallic–chitosan complex hydrogels with different cupric and zinc ions content. Scanning electron microscopy (SEM) revealed changes in the morphology from the microstructure with larger, tubular pores for aerogels with higher Zn content, to the sheets-like structure with long pores for samples with higher Cu content. FTIR analysis indicated the formation of bimetallic–chitosan aerogels. The obtained X-ray diffraction patterns showed a broadening of chitosan's characteristic diffraction maximum, while characterization of physical properties showed decreased swelling ability and increased shear modulus with higher Cu content. ICP-MS results showed a negligible amount of copper and zinc ions released under physiological conditions during 24 h indicating a strong physical crosslink between metal ions and chitosan chains. Furthermore, accelerated in vitro degradation showed that hydrogels maintained good stability during four weeks of lysozyme activity. The MTT assay indicated that the cytotoxicity of Cu2+–Zn2+/chitosan complexes could be adjusted by the amount of cupric ions. All results imply that Cu2+ and Zn2+ ions act as physical crosslinkers of the polymer network. Also, results are in agreement with the prediction of density functional theory (DFT) which indicated stronger chitosan–Cu tetrahedral aqua complex interactions in comparison to the chitosan–[Zn(H2O)4]2+ interactions.

Boosting Water Evaporation by Construction of Photothermal Materials with a Biomimetic Black Soil Aggregate Structure.

Solar-driven interfacial evaporation is considered an efficient way to get fresh water from seawater. However, the low evaporation rate, surface salt crystallization, and low energy collection of the photothermal evaporation layer limit its further application in an outdoor freshwater field. And the aggregate structure design of the material itself is often ignored in solar-driven water evaporation. Black soil (BS), with a unique soil aggregate structure, is rich in tubular pores, which can be used for multilevel sunlight utilization and good capillary water transport. Based on the extraordinary photothermal properties and pumping capacity of BS, a reasonable unidirectional salt-collecting device is designed, which can realize long-term collection of mineral salts and continuous evaporation of seawater and generate electric energy in the continuous evaporation. Inspired by the unique aggregate structure, the photothermal material doping of halloysite and nigrosin will simulate the generation of this aggregate structure and retain a good water transport effect while obtaining multistage utilization of sunlight. The solar-driven evaporation rate of a nigrosin-halloysite solar steam generator is 1.75 kg m-2 h-1 under 1 kW m-2 mimic solar radiation; it can achieve stable salt leaching-induced voltage generation of 240 mV. This work demonstrates not only a solar evaporator that can continuously achieve desalination but also the design strategy of BS-like aggregate photothermal materials, which promotes the development of low-cost resource recovery and energy generation for practical outdoor seawater desalination.

Silver and Gold Pillarplex Pseudorotaxanes from α,ω-Dicarboxylic Acids.

A series of pseudorotaxanes with supramolecular organometallic silver(I) and gold(I) pillarplexes acting as rings and different α,ω-dicarboxylic acids as axle components are reported. The successful formation of the host-guest complexes is shown by 1 HNMR spectroscopy and respective NMR titration. Additional evaluation with ITC titration experiments yielded dissociation constants (Kd ) ranging from 10-5 to 10-7 M. Single-crystal X-Ray diffraction analysis reveals a particularly exciting pore alignment of different examples in the solid state depending on the length of the guest. The work highlights, that dicarboxylic acids can penetrate the tight tubular pillarplex pore, paving the way to future mechanically interlocked molecules and materials.

Response mechanism of soil structural heterogeneity in permafrost active layer to freeze–thaw action and vegetation degradation

The soil structure is the key parameter that regulate soil water–heat–solute migration. To date, much remains unknown about the interaction mechanism between soil structure and the external environment in the permafrost regions. In this study, the undegraded meadow and degraded bare land in the permafrost region of the Qinghai–Tibet Plateau were used as research objects, and the soil structure characteristics and their influencing factors of the two sample sites were studied based on in situ hydrothermal observation data and CT scan. The results showed that the macropore system of the undegraded meadow was dominated by connected pores, with a small number of macropores, but the large volume, the shape mainly was elongated, and the connectivity was good. The degraded bare ground was dominated by isolated pores, with more large pores but smaller volume, more regular pore shape, and less pore connectivity than undegraded meadow. The macropore structure in both samples was affected by vegetation, freeze–thaw action, and soil moisture content. The undegraded meadow formed connected pores with mainly tubular pore aggregates in the soil layer above 23 cm due to the protective effect of vegetation roots, and only a few isolated pores existed in the deep soil layer below 23 cm due to weak freeze–thaw action and low moisture content. The daily freeze–thaw cycle days were long, and the complete freezing days were short for the degraded bare land. The frequent freeze–thaw action produced connected pores dominated by fractures, and many isolated pores, while the high water content of the deep soil intensified the freeze–thaw action, producing a large number of isolated pores and also increasing the depth of occurrence of macropores. The difference in the soil pore deepens the understanding of the relationship between the soil macropore and the soil hydrothermal process.

Effects of Jet-Grouting Piles on Loess Tunnel Foundation with Centrifugal Model Tests

Loess is a common soil layer of geological movement. It has macropores, vertical joints, and tubular pores and also low strength and strong water sensitivity. When building a tunnel in a weak loess stratum (Q3 loess or Q4 loess), the poor geological characteristics of loess usually bring great difficulties to the construction of tunnel invert, and it is very easy to cause subsidence at the tunnel base, uneven subsidence at the tunnel bottom, and cracks in the road and lining. The use of jet-grouting piles to strengthen the weak loess foundation is an effective method to improve the geological characteristics of loess. To investigate the effect of jet-grouting piles on the reinforcement of the tunnel foundation in weak loess areas, centrifugal model tests were used to analyze the subsidence and structural mechanics response characteristics of the tunnel base under the influence of jet-grouting pile length and pile diameter. Research shows that subsidence at the tunnel bottom can be reduced effectively and the adjustment time of the surrounding rock stress can be shorten significantly when using jet-grouting piles to reinforce the tunnel foundation. The length of the jet-grouting pile is better than the diameter in improving the strength of the foundation. However, with the improvement in the strength of jet-grouting piles, the efficiency of foundation reinforcement is reduced, the surrounding rock pressure and lining stress gradually increase, and the construction economy and structural safety are gradually reduced. When selecting parameters of jet-grouting pile, consideration should be given to safety, economy, and ease of construction.

3D-Printed Flat-Bone-Mimetic Bioceramic Scaffolds for Cranial Restoration.

The limitations of autologous bone grafts necessitate the development of advanced biomimetic biomaterials for efficient cranial defect restoration. The cranial bones are typical flat bones with sandwich structures, consisting of a diploe in the middle region and 2 outer compact tables. In this study, we originally developed 2 types of flat-bone-mimetic β-tricalcium phosphate bioceramic scaffolds (Gyr-Comp and Gyr-Tub) by high-precision vat-photopolymerization-based 3-dimensional printing. Both scaffolds had 2 outer layers and an inner layer with gyroid pores mimicking the diploe structure. The outer layers of Gyr-Comp scaffolds simulated the low porosity of outer tables, while those of Gyr-Tub scaffolds mimicked the tubular pore structure in the tables of flat bones. The Gyr-Comp and Gyr-Tub scaffolds possessed higher compressive strength and noticeably promoted invitro cell proliferation, osteogenic differentiation, and angiogenic activities compared with conventional scaffolds with cross-hatch structures. After implantation into rabbit cranial defects for 12 weeks, Gyr-Tub achieved the best repairing effects by accelerating the generation of bone tissues and blood vessels. This work provides an advanced strategy to prepare biomimetic biomaterials that fit the structural and functional needs of efficacious bone regeneration.

Calcined nanosized tubular halloysite for the preparation of limestone calcined clay cement (LC3)

Halloysite is a kind of 1:1 clay mineral having a special nanosized tubular morphology and pore structure. In this work, nanosized tubular halloysite calcined at 750 °C (Hal750) and limestone (LS) were used to partially replace the ordinary Portland cement (OPC) for the preparation of limestone calcined clay cement (LC3). The mechanical properties and microstructure of LC3 were studied. The results revealed that the obtained LC3 had higher early compressive strengths on 3 and 7 days than did plain OPC. LC3 with a replacement ratio of 22.5% (containing 15.0% Hal750 and 7.5% LS) resulted in maximum compressive strength of 46.38 MPa, being 9.4% higher than OPC's after 28 days of curing. Further, LC3 featured a compact microstructure and smaller critical pore size than OPC, which is mainly because more additional C-(A)-S-H, hemicarboaluminate (Hc), and monocarboaluminate (Mc) were formed in LC3 system, thus contributing to the matrix densification and strength development. However, when the replacement ratio exceeded 37.5%, the insufficient portlandite (CH) limited the pozzolanic reaction with Hal750, leaving excess Hal750 in the LC3 that led to their inhomogeneous microstructure, and thus weakened the mechanical properties. These results show that halloysite is a promising material for the preparation of LC3 whose properties are sensitive to the replacement ratio used.

Anisotropic and Lightweight Carbon/Graphene Composite Aerogels for Efficient Thermal Insulation and Electromagnetic Interference Shielding.

High-performance and lightweight carbon aerogels (CAs) have attracted considerable attention in various fields such as electrochemistry, catalysis, adsorption, energy storage, and so on. However, finding an environmentally friendly and efficient preparation method and achieving a controllable performance of CAs are still a challenge. Herein, a series of anisotropic carbon/graphene composite aerogels were synthesized by unidirectional freezing of polyamic acid ammonium salt/graphene oxide (PAS/GO) suspension followed by lyophilization, thermal imidization, and carbonization. The prepared aerogels presented a tubular pore structure oriented along the freezing direction. The GO dispersed in the polymer matrix reinforced the skeleton of aerogels, which significantly inhibited the volume shrinkage during the preparation process, thus giving low densities of 0.074-0.185 g cm-3. In addition, the oriented pore structure endowed the composite aerogels with obviously anisotropic heat insulation performance. The radial thermal conductivity was as low as 0.038 W m-1 K-1 at the density of 0.074 g cm-3. When the initial content of GO rose to 20 phr, the resultant aerogels exhibited a high electrical conductivity of about 0.77 S cm-1 in the radial direction and the electromagnetic interference shielding effectiveness (EMI SE) reached 54.6 dB at the same time. Therefore, this study provided a facile and environmentally friendly method to prepare lightweight and anisotropic carbon aerogels.

Hybrid Pyridine–Pyridone Foldamer Channels as M2‐Like Artificial Proton Channels

AbstractCurrently, completely abiotic channel systems that concurrently reproduce the high selectivity and high permeation rate of natural protein channels are rare. Here, we provide one such biomimetic channel system, i.e., a novel family of helically folded hybrid amide foldamers that can serve as powerful artificial proton channels to mimic key transport features of the exceptionally selective Matrix‐2 (M2) proton channels. Possessing an angstrom‐scale tubular pore 3 Å in diameter, these low water permeability artificial channels transport protons at a rate 1.22 and 11 times as fast as gramicidin A and M2 channels, respectively, with exceptionally high selectivity factors of 167.6, 122.7, and 81.5 over Cl−, Na+, and K+ ions. Based on the experimental and computational findings, we propose a novel proton transport mechanism where a proton may create a channel‐spanning water chain from two or more short water chains to facilitate its own transmembrane flux via the Grotthuss mechanism.

Hybrid Pyridine-Pyridone Foldamer Channels as M2-Like Artificial Proton Channels.

Currently, completely abiotic channel systems that concurrently reproduce the high selectivity and high permeation rate of natural protein channels are rare. Here, we provide one such biomimetic channel system, i.e., a novel family of helically folded hybrid amide foldamers that can serve as powerful artificial proton channels to mimic key transport features of the exceptionally selective Matrix-2 (M2) proton channels. Possessing an angstrom-scale tubular pore 3 Å in diameter, these low water permeability artificial channels transport protons at a rate 1.22 and 11 times as fast as gramicidin A and M2 channels, respectively, with exceptionally high selectivity factors of 167.6, 122.7, and 81.5 over Cl- , Na+ , and K+ ions. Based on the experimental and computational findings, we propose a novel proton transport mechanism where a proton may create a channel-spanning water chain from two or more short water chains to facilitate its own transmembrane flux via the Grotthuss mechanism.

Dendritic Fibrous Nanosilica: Discovery, Synthesis, Formation Mechanism, Catalysis, and CO2 Capture-Conversion.

ConspectusSilica-based mesoporous nanomaterials have been widely used for a range of applications. Although mesopore materials (such as MCM-41 and SBA-15) possess high surface area, due to their tubular pore structures, pore accessibility is restricted, which causes limitations in mass transport. A new nanosilica was needed to overcome these challenges, including better accessibility, controllable particle size, and good stability. In 2010, my group invented dendritic fibrous nanosilica (DFNS), which has now become a family of novel nanosilicas. DFNS has several unique properties: (i) Tunable particle sizes (50 to 1200 nm), (ii) high surface area (500 to 1200 m2/g), (iii) tunable pore volume (0.32 to 2.18 cm3/g), (iv) wide pore size distribution (3.7 to 25 nm) characterized by radially oriented pores, (v) controllable fiber density (number of fibers per sphere), (vi) variable pore size and pore volume, (vi) high thermal (∼800 °C) and hydrothermal stability, and (vii) mechanical stability (∼130 MPa). DFNS possesses unique dendritic fibrous morphology, and hence can be reached from all sides and easily accessible. DFNS can now be synthesized using a open refluxing protocol, which allowed the scale-up of the process with a sustainable E-factor. In the last 12 years, the DFNS family of materials has been extensively studied for their formation mechanism and range of applications such as catalysis, solar energy harvesting, CO2 capture, CO2 conversion, sensing, biomedicine, energy storage and many more.This Account discusses the invention of DFNS, its synthesis with tunable particle size, textural properties (surface area, pore volume, and pore size), and fiber density. In addition, the DFNS formation mechanism via the complex interplay of self-assembly, the dynamics, and coalescence of bicontinuous microemulsion droplets (BMDs) is discussed. Finally, applications of DFNS in a range of fields, that include catalysis, photocatalysis, synthesis of plasmonic black gold, nanosponges of aluminosilicates, CO2 capture, and CO2 conversion to fuel, are presented.

On the issue of textured crystallization of Ba(NO3)2 in mesoporous SiO2: Raman spectroscopy and lattice dynamics analysis

The lattice dynamics of preferentially aligned nanocrystals formed upon drying of aqueous Ba(NO3)2 solutions in a mesoporous silica glass traversed by tubular pores of approximately 12 nm are explored by Raman scattering. To interpret the experiments on the confined nanocrystals polarized Raman spectra of bulk single crystals and X-ray diffraction experiments are also performed. Since a cubic symmetry is inherent to Ba(NO3)2, a special Raman scattering geometry was utilized to separate the phonon modes of Ag and Eg species. Combining group-theory analysis and ab initio lattice dynamics calculations a full interpretation of all Raman lines of the bulk single crystal is achieved. Apart from a small confinement-induced line broadening, the peak positions and normalized peak intensities of the Raman spectra of the nanoconfined and macroscopic crystals are identical. Interestingly, the Raman scattering experiment indicates the existence of comparatively large,∼10–20 μm, single-crystalline regions of Ba(NO3)2 embedded in the porous host, near three orders of magnitude larger than the average size of single nanopores. This is contrast to the initial assumption of non-interconnected pores. It rather indicates an inter-pore propagation of the crystallization front, presumably via microporosity in the pore walls.