Macroporous Morphology Research Articles

Synthesis and Characterization of Robust γ-Alumina Monolith with Hierarchical Pore Structure, High Specific Surface Area and Novel Macropore Morphology

A three-dimensional interconnected macroporous alumina monolith was successfully prepared by phase separation combined with microwave-hydrothermal process in ammonia solution. The material calcined...

Facile preparation of macro-mesoporous zirconium titanate monoliths via a sol–gel reaction accompanied by phase separation

Abstract

Assessing the effects of land use change from rice to vegetable on soil structural quality using X-ray CT

The conversion of cereal to vegetable represents a significant shift in land use in China, and it causes significant changes in soil properties. Most studies have only focused on chemical or biological properties; few have investigated soil structure. Soil structure, especially macropore space, is very important for plant growth because of its relation to important soil functions and processes, such as gas diffusion and water permeability. The objective of this study was to assess the effect of land use conversion from rice to vegetable on soil macropores (>50 μm) measured by computed tomography (CT) and to examine the relationships between CT-measured pore characteristics and soil chemical properties. By using space instead of time, we sampled three land uses – rice/wheat rotation (RWR), open-field vegetable (OFV) and plastic-greenhouse vegetable (PGV) – in a tilled and plow pan layer in a suburban area of Nanjing, China, and analyzed the basic physicochemical properties and CT-measured macropore characteristics. The results showed that the tilled layer soil had a significant response to the land use change. The macroporosity decreased from 11.5% under RWR to 8.0% under OFV and 5.8% under PGV, and the decreased portion consisted mainly of elongated large macropores (>1000 μm). In addition, the macropore morphology of vegetable fields also showed degradation, with a higher degree of anisotropy (DA) and lower fractal dimension (FD) and connectivity compared to those under RWR, but PGV experienced a higher degree of degradation than did OFV. This study also showed that soil structure degradation was significantly correlated with decreasing soil organic matter (SOM). Increasing the amount of organic fertilizer applied might improve the SOM content and therefore improve the soil structure. Based on the linear regression equation, adding 1 g of SOM per kilogram of soil can improve the macroporosity by 0.54 m3 m−3.

A Study of Cryostructuring of Polymer Systems. 51. The Combined Influence of Porous Cellulose-Containing Dispersed Fillers and Salting-Out Electrolytes on the Physicochemical Properties of Composite Poly(vinyl alcohol) Cryogels

Composite poly(vinyl alcohol) (PVA) cryogels comprising dispersed porous cellulose-containing fillers (microcrystalline cellulose, wood sawdust) and salting-out electrolytes (Na2SO4, NaF) have been prepared by freezing at –20°C, incubation in the frozen state for 12 h, and defrosting at a rate of 0.03°C/min. The influence of the chemical nature and concentration of the soluble additives and fillers on the rheological behavior of initial suspensions, as well as the morphology of macropores and physicochemical and thermophysical properties of corresponding composite cryogels, has been studied. Viscometric studies have shown that, because of the salting-out action of the electrolytes, the viscosity of PVA solutions decreases due to the compaction of macromolecular coils. However, in the case of filler suspensions, the viscosity increases owing to the enhancement of the adhesion interactions between the discrete and continuous phases, thereby affecting the rigidity and heat endurance of filled cryogels resulting from the freezing–defrosting of such suspensions. The most pronounced increase in the compression elasticity modulus and heat endurance of the composites takes place upon the combined incorporation of a porous filler and a salting-out electrolyte into the cryogel matrix. The microstructure of both unfilled and filled cryogels has been studied by scanning electron microscopy. Substantial changes have been revealed in the macroporous morphology of these objects upon the incorporation of a porous dispersed cellulose-containing filler or a salting-out electrolyte separately and, especially, upon their combined incorporation into the matrix of the PVA cryogel.

Size Distribution and Characteristics of Chitin Microgels Prepared via Emulsified Reverse-Micelles.

Chitin was extracted from local snow crab shell waste and used as a raw material in the fabrication of porous spherical microgels. The chitin microgels were obtained using a batch process of emulsification and, afterward, gelation. The effects of chitin concentrations, oil and water phase ratios (O:W), surfactants, and gelation on the size distribution and morphology of the microgels were investigated. The extracted chitin possessed α-chitin with a degree of acetylation of ~60% and crystallinity of 70%, as confirmed by Fourier Transform Infrared Spectroscopy (FTIR) and X-Ray Powder Diffraction (XRD). In the reverse-micellar emulsification, different chitin concentrations in NaOH solution were used as aqueous phases, and n-hexane media containing Span 80-based surfactants were used as dispersion phases. Various HCl solutions were used as gelling agents. Microgels with sizes ranging from ~5–200 μm were obtained relying on these studied parameters. Under the condition of 3% w/w chitin solution using O:W of 15:1 at 5% w/w of Span 80 (hydrophilic-lipophilic balance; HLB of 4.3), the gelation in the emulsified reverse micelles was better controlled and capable of forming spherical microgel particles with a size of 7.1 ± 0.3 μm, when 800 μL of 1 M HCl was added. The prepared chitin microgel exhibited macro-pore morphology and swelling behavior sensitive to the acidic pH.

Structural properties of disordered macroporous La2O2CO3/ZnO materials prepared by a solution combusion method

Disordered macroporous La2O2CO3/ZnO materials were prepared by a solution combustion method, and then their microstructures and La2O2CO3 phases were investigated as functions of La/Zn ratios and calcination temperatures. All of the materials prepared by the solution combustion method clearly showed disordered macroporous morphology whose framework was composed of ZnO and La2O2CO3 nanoparticles. A monoclinic La2O2CO3 structure was mainly formed in the disordered macroporous materials at La/Zn=1 and 2. In contrast, the conventional coprecipitation of La2O2CO3/ZnO materials dominantly formed a hexagonal La2O2CO3 phase with aggregating morphology of ZnO and La2O2CO3 nanoparticles. However, nanocrystalline sizes of ZnO (7–10 nm) and monoclinic La2O2CO3 (12–14 nm) in the disordered macroporous structure were much smaller than those (29–36 nm for ZnO and 44–58 nm for hexagonal La2O2CO3) by conventional co-precipitation. In addition, the high temperature calcination at 700 °C increased the ZnO nanocrystallite size (24 nm) in the disordered macroporous framework, with transforming La2O2CO3 into La2O3. This result implies that the interaction between monoclinic La2O2CO3 and ZnO in the disordered macroporous structure inhibited ZnO nanoparticle agglomeration.

Fabrication of micro-mesopores in macroporous poly (formaldehyde-melamine) monoliths via reaction-induced phase separation in high internal phase emulsion template

A one-step strategy of preparing hierarchical porous poly (formaldehyde-melamine) monoliths (PFM) with high specific surface area was proposed. Based on the high internal phase emulsion (HIPE) template, the removal of dispersed phase (liquid paraffins) and the reaction-induced phase separation in continuous phase (the solution of parafomaldehyde and melamine) could generate the macropores, mesopores and micropores in PFM simultaneously. As a result, the highest specific surface areas of the prepared PFM could reach 210 m2/g, which was obviously higher than that of traditional polyHIPE. The effect of the constitution of the continuous phase of HIPE on the macroporous morphologies, specific surface areas, and micropore volume of PFM were investigated in detail. Moreover, the formation mechanism of micropores and mesopores by reaction-induced phase separation was proposed. Finally, the obtained PFM was applied as CO2 absorbent and the adsorption properties were studied.

Фотоанодирование n-Si в присутствии перекиси водорода: зависимость от напряжения

AbstractThe fundamental aspects of the electrochemical etching of lightly doped n -Si under backside illumination conditions are studied in a solution with a low HF concentration and a high concentration of hydrogen peroxide. The data obtained are compared with those for a control electrolyte containing no H_2O_2. The morphology of the self-organized macropores, their growth rate, porosity, effective valence, and the amount of dissolved silicon are examined in relation to the applied voltage. The anodization kinetics at low and high bias voltages is analyzed. It is found that, under the same illumination, the initial photocurrent in the peroxide electrolyte is approximately twice lower than in the aqueous electrolyte, which makes it possible to state that the quantum efficiency of the photocurrent is lower. As, however, the etching duration is made longer, the current in the peroxide electrolyte strongly increases to become higher than that in the control electrolyte based on H_2O. It is found that, in the presence of H_2O_2, the depthwise growth rate of the macropores increases by more than a factor of 2, and the porosity decreases. The vertical macropore channels have a diameter smaller than that for macropores formed in the aqueous electrolyte and their walls are poorly passivated, which causes branching and the formation of secondary mesopores, the number of which grows with increasing voltage. The effective valence of silicon dissolution in the presence of H_2O_2 decreases to less than 2. The results are interpreted in terms of the Gerischer and Kolasinski models.

Photoanodization of n-Si in the Presence of Hydrogen Peroxide: Voltage Dependence

The fundamental aspects of the electrochemical etching of lightly doped n-Si under backside illumination conditions are studied in a solution with a low HF concentration and a high concentration of hydrogen peroxide. The data obtained are compared with those for a control electrolyte containing no H2O2. The morphology of the self-organized macropores, their growth rate, porosity, effective valence, and the amount of dissolved silicon are examined in relation to the applied voltage. The anodization kinetics at low and high bias voltages is analyzed. It is found that, under the same illumination, the initial photocurrent in the peroxide electrolyte is approximately twice lower than in the aqueous electrolyte, which makes it possible to state that the quantum efficiency of the photocurrent is lower. As, however, the etching duration is made longer, the current in the peroxide electrolyte strongly increases to become higher than that in the control electrolyte based on H2O. It is found that, in the presence of H2O2, the depthwise growth rate of the macropores increases by more than a factor of 2, and the porosity decreases. The vertical macropore channels have a diameter smaller than that for macropores formed in the aqueous electrolyte and their walls are poorly passivated, which causes branching and the formation of secondary mesopores, the number of which grows with increasing voltage. The effective valence of silicon dissolution in the presence of H2O2 decreases to less than 2. The results are interpreted in terms of the Gerischer and Kolasinski models.

Mitigating Metal Dendrite Formation in Lithium-Sulfur Batteries via Morphology-Tunable Graphene Oxide Interfaces.

Despite issues related to dendrite formation, research on Li metal anodes has resurged because of their high energy density. In this study, graphene oxide (GO) layers are decorated onto Li metal anodes through a simple process of drop-casting and spray-coating. The self-assembly of GO is exploited to synthesize coatings having compact, mesoporous, and macroporous morphologies. The abilities of the GO coatings to suppress dendrite formation are compared through Li|Li symmetrical cell charging at a current density of 5 mA cm-2 for 2000 cycles-a particularly abusive test. The macroporous structure possesses the lowest impedance, whereas the compact structure excels in terms of stability. Moreover, GO exhibits a low nucleation overpotential and is transformed into reduced GO with enhanced conductivity during the operation of the cells; both factors synergistically mitigate the issue of dendrite formation. Li-S batteries incorporating the GO-decorated Li anodes exhibit an initial capacity of 850 mA h g-1 and maintain their stability for 800 cycles at a C-rate of 1 C (1675 mA h g-1), suggesting the applicability of GO in future rechargeable batteries.

Three-dimensional carbon foam nanocomposites for thermal energy storage

Nanocomposites consisting of paraffin/graphene nanoplatelets mix embedded in carbon foams via vacuum infiltration were fabricated with the aim of developing new phase change material (PCM) formulation with excellent shape stabilization, improved thermal conductivity and outstanding thermal reliability and structural stability. Physicochemical and thermal properties of the nanocomposites were evaluated using a suite of techniques such as scanning and transmission electron microscopy, X-ray diffraction, attenuated total reflection - Fourier transform infrared spectroscopy, nitrogen adsorption analyzer, differential scanning calorimetry, mechanical tester, Raman spectroscopy, thermal conductivity analyzer and thermogravimetric analyzer. The carbon foams exhibited good cyclic compressive behavior at a strain of up to 95% and kept part of their elastic properties after cyclic testing. Due to the robust mechanical integrity and layered meso-/macroporous morphology of these carbon foams, the nanocomposites are well equipped to cope with volume changes without leaking during thermal cycling. A 141% thermal conductivity enhancement observed for the carbon foam nanocomposite demonstrates the contributing role of the carbon foam in creating effective heat transfer through its conductive 3D network. The results have shown that proper chemical modification and subsequent carbonization of the low cost porous foams can lead to ultralight multifunctional materials with high mechanical and physical properties suitable for thermal energy storage applications.

Influence of Hydrogen Peroxide on the Photoanodization of n-Si in the Breakdown Mode

The electrochemical etching of n-Si (100) in an electrolyte composed of 4% HF solution in 30% hydrogen peroxide is experimentally studied at a voltage exceeding the breakdown voltage. The effect of the illuminance of the wafer back side on the porous-structure morphology and such parameters as porosity, effective valence, and pore growth rate are examined. The data obtained are compared with those for structures subjected to photoanodization in an aqueous electrolyte at the same HF concentration. It is found that the presence of hydrogen peroxide strongly changes the morphology of macropores, makes their diameter smaller, and raises by a factor of ~2 the rate of growth deeper into the substrate. In the presence of H2O2, there appear inclined secondary pores oriented at an angle of 15°–35° to the main channel axis and a number of breakthrough mesopores propagating in the 〈100〉 directions in the plane parallel to the sample surface. The effective valence of the electrochemical dissolution of silicon in the HF:H2O2 electrolyte at a low illumination level is close to unity and grows with increasing light intensity, always being smaller than 2.

Superhydrophobic and Compressible Silica-polyHIPE Covalently Bonded Porous Networks via Emulsion Templating for Oil Spill Cleanup and Recovery

We synthesize porous polyHIPE networks with silanol functionalities in the polyHIPE backbone. These silanol functionalities are used for covalent bonding with silica aerogels embedded in the polyHIPE. Covalent bonding between silica and polyHIPE networks are confirmed using Fourier-transform infrared spectroscopy and scanning electron microscopy. Silica aerogels covalently bonded with polyHIPE network show macroporous and mesoporous morphologies and possess excellent properties like high bendability, high elasticity, superhydrophobicity (~160°), low density (~0.128 g/cm3), and low thermal conductivity (~0.045 W/m·K). Oil absorption from water/oil mixtures and recovery of the absorbed oil (by squeezing) from flexible silica-polyHIPE networks is studied. The silica-polyHIPE is shown to absorb crude oil ~16-times its own weight and can be reused multiple times after recovery. Hence, such materials are very important for oil spill cleanup applications from aqueous systems.

Cryostructuring of Polymeric Systems. 49. Unexpected "Kosmotropic-Like" Impact of Organic Chaotropes on Freeze⁻Thaw-Induced Gelation of PVA in DMSO.

Urea (URE) and guanidine hydrochloride (GHC) possessing strong chaotropic properties in aqueous media were added to DMSO solutions of poly(vinyl alcohol) (PVA) to be gelled via freeze–thaw processing. Unexpectedly, it turned out that in the case of the PVA cryotropic gel formation in DMSO medium, the URE and GHC additives caused the opposite effects to those observed in water, i.e., the formation of the PVA cryogels (PVACGs) was strengthened rather than inhibited. Our studies of this phenomenon showed that such “kosmotropic-like” effects were more pronounced for the PVACGs that were formed in DMSO in the presence of URE additives, with the effects being concentration-dependent. The additives also caused significant changes in the macroporous morphology of the cryogels; the commonly observed trend was a decrease in the structural regularity of the additive-containing samples compared to the additive-free gel sample. The viscosity measurements revealed consistent changes in the intrinsic viscosity, Huggins constant, and the excess activation heat of the viscosity caused by the additives. The results obtained evidently point to the urea-induced decrease in the solvation ability of DMSO with respect to PVA. As a result, this effect can be the key factor that is responsible for strengthening the structure formation upon the freeze–thaw gelation of this polymer in DMSO additionally containing additives such as urea, which is capable of competing with PVA for the solvent.

Comparison of n-Si photoanodization in organic and aqueous electrolytes

The electrochemical etching of n-Si in a hydrofluoric solution in dimethylformamide under backside illumination has been experimentally studied. The dependences of the morphology of macropores being formed, porosity, etching rate, and effective valence on voltage and light intensity were examined. The results are compared with the data obtained under the same conditions in a H2O-based control electrolyte with the same hydrofluoric concentration. It is shown that the photoanodization in an organic electrolyte is characterized by intensive formation of secondary pores, rapid transition to electropolishing, and better conditions for separation of the porous layer from a substrate. Attention is given to the anodization in the breakdown mode, for which the difference from the aqueous electrolyte is the most pronounced. The thus formed layers have a higher porosity, lower pore growth rate, unusual orientation of secondary pores along the 〈1 1 1〉 crystallographic axis, and, under high-intensity illumination, large value of the effective valence.

Using the X‐ray computed tomography method to predict the saturated hydraulic conductivity of the upper root zone in the Loess Plateau in China

Core Ideas Computed tomography (CT)‐measured properties were in the order: soil under Q. liaotungensis > P. tabuliformis > C. korshinskii > M. sativa. The parameters measured by CT could help estimate saturated hydraulic conductivity (Ksat) in the Loess Plateau. Macropore quantity has a higher R2 for predicting Ksat than the morphology of macropores. The recovery of natural vegetation significantly improves soil macroporosity through root decay and biological activity. Macropores are preferential pathways for the movement of water to deep soil. However, the quantification of soil macropore structure and its relationship with soil hydraulic conductivity (Ksat) are not well understood. We characterized the macropores under different vegetation types to evaluate the effects of macropores on Ksat. Undisturbed soil cores were collected from four treatments: areas dominated by Quercus liaotungensis Koidz.(QLI), Pinus tabuliformis Carrière (PTA), Caragana korshinskii Kom. (CKO), and Medicago sativa L.(MSA). A medical computed tomography (CT) scanner was used to acquire images with a voxel size of 0.977 by 0.977 by 1.000 mm for depths of 0 to 360 mm. We used ImageJ software to quantify the macropore properties. Soil structure and Ksat improved with the succession of vegetation. The mean macropore volume fraction across the soil cores for the QLI, PTA, CKO, and MSA treatments were 6.6, 3.5, 1.3, and 0.6% within a 4900‐mm2 area, respectively. Macropore quantity (volume fraction and number) had a higher R2 for predicting Ksat than macropore morphology (branch density, connectivity density, and junction density). Moreover, the grayscale values were negatively correlated with Ksat and accounted for 78.8% of the variation in Ksat. Grayscale values, volume fraction, and the number of macropores were the best combination of CT‐measured parameters for predicting Ksat, accounting for 81.9% of the variation in Ksat. The CT‐measured parameters could be used to estimate Ksat in the upper root zone in the Loess Plateau.

Macroporosity of a Typic Argiudoll with different cropping intensity under no-tillage

Soil macropores are dominant pathways of water flow and their impact on hydraulic properties is directly related to their geometrical and topological characteristics. A number of field and micromorphological analysis have shown that agriculture management under no-tillage promotes the development of a microstructure characterized by platy aggregates and horizontal planes in the topsoil, together with a densification at a subjacent layer, thus raising questions about physical properties and water dynamics under this system of cultivation. Moreover, scarce information is available about the evolution of pore architecture and physical parameters in soils under no-till with different cropping intensity. The objective of this work was to evaluate soil porosity in a silty loam A horizon of a Typic Argiudoll (Monte Buey series) of northern Pampa Region (Argentina) under two no-tilled contrasting managements: Good Agricultural Practices (GAP) –highly intensified cropping sequence including corn and wheat in addition to soybean-, Poor Agricultural Practices (PAP) -simplified crop sequence, with predominance of soybean- and a Natural Environment (NE) as reference. Topsoil porosity was assessed by micromorphology, micromorphometry and water retention curves approach, and the values obtained were related to some physical and chemical variables. Results of the morphological analysis revealed important differences between both agricultural treatments. In the surface layer in GAP, platy aggregates are thick and result from the cohesion of rounded microaggregates of biological origin; in PAP they are thin and dense, resulting mostly from compaction of individual soil particles and small microaggregates. A soil densification is evident in both agricultural treatments at 5-10 cm depth, although the morphology and size of aggregates and pores also differ between them. Micromorphometric analyses have shown differences in total macroporosity as well as in the size, morphology and orientation of macropores between both treatments. Macroporosity values obtained by digital methods were coincidently reflected by the pressure plate method. Porosity variables measured by digital analysis, in particular elongated pores and pore orientation, appear more sensitive than other soil properties (total carbon, aggregate stability, bulk density) in discriminating treatments. Although no-till cultivation led to the formation of platy microstructures and a decrease of soil porosity compared to NE, both agricultural treatments presented optimal values of Ks and water movement was not impaired. As expected, all morphological and analytical soil variables were better in the NE treatment. In addition, it was interesting to verify that the values of several parameters were close or similar between GAP and NE. Even when more intensified crop sequence (GAP) increases machinery traffic, morphological, physical and chemical soil properties were here improved compared to PAP. In this case, the higher proportion of different graminea into the agricultural cycle, besides its effect on the development of root biopores, seems to promote a higher fauna activity which effectively counteracts the vertical mechanical compression produced by traffic. These results suggest that, in addition to the known benefits of non-tillage on soil conservation, the improvement of various soil properties could be achieved by integrating this method of cultivation with suitable agricultural managements.

Tuning bimodal porosity in TiO2 photoanodes towards efficient solid-state dye-sensitized solar cells comprising polysiloxane-based polymer electrolyte

Abstract This article describes a cell architecture that achieves enhanced light harvesting with less dye quantity while simultaneously improving the performance of the polysiloxane-based solid-state dye-sensitized solar cells (DSSCs). We report the synthesis of bimodal mesoporous anatase TiO2 films by a dual templating approach, combining a block-copolymer template (Pluronic P123) and polystyrene nanospheres (PS) as soft and hard templates, respectively. The AFM and TEM analysis of TiO2 films revealed a mixture of mesoporous and macroporous morphology in which dual porosity is generated by combustion of soft and hard templates. The size of the macropores was varied by employing PS beads with different diameters (62, 130 and 250 nm). The influence of the macropore size on the dye loading and pore infiltration is the main purpose of this article. The bimodal porosity leads to increased light scattering due to enhanced optical path length, and better pore infiltration of the polysiloxane electrolyte is achieved. The amount of dye uptake by the dual films is lower than that of soft films because the large pore size reduces the total surface area. The optimum bimodal structure was obtained when combining P123 surfactant and the 130 nm PS beads leading to the lowest charge transfer resistance and a high efficiency for DSSCs is reported with both liquid and polymer electrolytes. Even if the dye uptake was lower, the photovoltaic performance has been maintained and improved in some devices. The open circuit voltage and fill factor were improved, owing to a successful joining of different effects i.e. increased light harvesting, facile electrolyte penetration and reduced charge recombination.

Single Cell Study of Water Transport in PEMFCs with Electrosprayed Catalyst Layers

AbstractWater transport in proton exchange membrane fuel cells (PEMFCs) with electrosprayed catalyst layers is analyzed by means of water collection measurements. With this aim, single cells have been studied with different catalyst layers configuration: electrosprayed layer in cathode (EScat), in anode (ESan), and in both electrodes (ESboth). The electrosprayed catalyst layers show macroporous morphology and superhydrophobicity (water contact angle θ > 150°) . Initial polarization curves, taken after a few hours from cell start‐up, show above 20% higher maximum power density of EScat and ESan cells, compared with a conventional cell (with no electrosprayed layers). The performance improvement is due to lower internal resistance of the cell according to the polarization curves. Stability of the cells under the dry‐gas operation conditions used during water collection measurements, shows to be high only for EScat, whereas ESan, ESboth, and conventional cells suffer degradation and frequent membrane failure. Water collection experiments at variable temperature and current density reflect larger water flow towards the anode for EScat cell than for the other configurations. It is concluded that the high performance and stability of EScat is due to the enhanced water back diffusion from cathode to anode driven by the superhydrophobic electrosprayed catalyst layer in cathode. Favored back diffusion improves water balance in the cell, membrane humidification, decreases the internal resistance, and precludes anode drying and cathode flooding. The optimal cell configuration is obtained with an electrosprayed catalyst layer in the cathode and a standard hydrophilic catalyst layer in the anode.

Effect of Pore Size, Morphology and Orientation on the Bulk Stiffness of a Porous Ti35Nb4Sn Alloy

The metal foams of a titanium alloy were designed to study porosity as well as pore size and shape independently. These were manufactured using a powder metallurgy/space-holder technique that allowed a fine control of the pore size and morphology; and then characterized and tested against well-established models to predict a relationship between porosity, pore size and shape, and bulk stiffness. Among the typically used correlations, existing power-law models were found to be the best fit for the prediction of macropore morphology against compressive elastic moduli, outperforming other models such as exponential, polynomial or binomial. Other traditional models such as linear ones required of updated coefficients to become relevant to metal porous sintered macrostructures. The new coefficients reported in this study contribute toward a design tool that allows the tailoring of mechanical properties through porosity macrostructure. The results show that, for the same porosity range, pore shape and orientation have a significant effect on mechanical performance and that they can be predicted. Conversely, pore size has only a mild impact on bulk stiffness.