3D Porous Microstructure Research Articles

Recent Advances in MXene-Based Aerogels for Electromagnetic Wave Absorption.

Developing lightweight, high-performance electromagnetic wave (EMW) absorbing materials those can absorb the adverse electromagnetic radiation or waves are of great significance. Transition metal carbides and/or nitrides (MXenes) are a novel type of 2D nanosheets associated with a large aspect ratio, abundant polar functional groups, adjustable conductivity, and remarkable mechanical properties. This contributes to the high-efficiency assembly of MXene-based aerogels possessing the ultra-low density, large specific surface area, tunable conductivity, and unique 3D porous microstructure, which is beneficial for promoting the EMW absorption. Therefore, MXene-based aerogels for EMW absorption have attracted widespread attention. This review provides an overview of the research progress on MXene-based aerogels for EMW absorption, focusing on the recent advances in component and structure design strategies, and summarizes the main strategies for constructing EMW absorbing MXene-based aerogels. In addition, based on EMW absorption mechanisms and structure regulation strategies, the preparation methods and properties of MXene-based aerogels with varieties of components and pore structures are detailed to advance understanding the relationships of composition-structure-performance. Furthermore, the future development and challenges faced by MXene-based aerogels for EMW absorption are summarized and prospected.

A phenazine-based conjugated microporous polymer as a high performing cathode for aluminium-organic batteries.

One of the possible solutions to circumvent the sluggish kinetics, low capacity, and poor integrity of inorganic cathodes commonly used in rechargeable aluminium batteries (RABs) is the use of redox-active polymers as cathodes. They are not only sustainable materials characterised by their structure tunability, but also exhibit a unique ion coordination redox mechanism that makes them versatile ion hosts suitable for voluminous aluminium cation complexes, as demonstrated by the poly(quinoyl) family. Recently, phenazine-based compounds have been found to have high capacity, reversibility and fast redox kinetics in aqueous electrolytes because of the presence of a CN double bond. Here, we present one of the first examples of a phenazine-based hybrid microporous polymer, referred to as IEP-27-SR, utilized as an organic cathode in an aluminium battery with an AlCl3/EMIMCl ionic liquid electrolyte. The preliminary redox and charge storage mechanism of IEP-27-SR was confirmed by ex situ ATR-IR and EDS analyses. The introduction of phenazine active units in a robust microporous framework resulted in a remarkable rate capability (specific capacity of 116 mA h g-1 at 0.5C with 77% capacity retention at 10C) and notable cycling stability, maintaining 75% of its initial capacity after 3440 charge-discharge cycles at 1C (127 days of continuous cycling). This superior performance compared to reported Al//n-type organic cathode RABs is attributed to the stable 3D porous microstructure and the presence of micro/mesoporosity in IEP-27-SR, which facilitates electrolyte permeability and improves kinetics.

Modeling the 4D discharge of lithium-ion batteries with a multiscale time-dependent deep learning framework

The lithium-ion battery (LIB) field is moving towards the direction of investigating spatially resolved physical phenomena in the 3D porous microstructure of electrodes. These pore-scale simulations give new insights into the local dynamics of lithiation/de-lithiation and charge transport. Nevertheless, the computational time of these simulations limits the integration of these models in optimization workflows of cycling conditions or electrode manufacturing processes.Machine learning models present a way of assessing in real-time the performance of materials. While several successful techniques for replicating simulations with machine learning have been proposed, this case study presents a more demanding problem, due to the necessity of understanding the behavior of heterogeneous 3D local data, as it evolves in time: this poses both a scientific and a technical challenge.To this end, we propose an autoregressive multiscale convolutional neural network model to predict relevant quantities at the pore-scale in the solid phase: the lithium concentration (in the active material) and potential (in the active material and carbon binder). These are ultimately used to reconstruct the battery discharge curve. 3D images of the electrode microstructures are the input to the network, trained with a dataset of finite element method simulations to predict the discharge behavior of the cathode side in lithium ion batteries.We propose this machine learning model as a proof-of-concept of the applicability of multiscale networks for time-dependent physics problems. The trained model exhibits very high accuracy (with errors lower than 2%) in forecasting the discharge behavior of new unseen cathodes.

Highly Stretchable and Sensitive Strain Sensor Based on Porous Materials and Rhombic‐Mesh Structures for Robot Teleoperation

AbstractWearable sensors for human motion capture offer a promising human–robot interface to control robots in the teleoperation scenario, where robots could function as the second body of human operators to fulfill tasks remotely and accurately. In this paper, a novel strain sensor based on a soft polyurethane (PU) sponge and carbon nanotubes (CNT) is designed for motion capture of human joints. The unique 3D porous microstructure of the PU‐CNT sponge provides the sensor with high sensitivity. To bridge the gap between the high sensitivity and high stretchability of the strain sensor, a rhombic‐mesh structure with optimized geometric parameters, in conjunction with a pre‐compression design, is proposed for strain sensor prototyping, which endows the sensor with an extra elongation rate during the stretching process. The proposed PU‐CNT strain sensor manifests promising sensing performance with a stretchability of up to 300% and a maximum gauge factor of 3893, together with long‐term durability, low detection limit, and fast response capacity. Finally, the validation of the strain sensor is carried out by deploying the sensor on a human elbow to realize the teleoperation of a robot arm, which could be monitored through the digital twin model of the robot in a real‐time manner.

High Efficient Catalyst of N‐doped Carbon Modified Copper Containing Rich Cu−N−C Active Sites for Electrocatalytic CO2 Reduction

AbstractThe synthesis of multi‐carbon products through electrochemical CO2 reduction reactions has attracted great interest from researchers. Herein, nitrogen‐ and carbon‐doped copper nanocatalyst (NC−Cu) containing abundant Cu−N−C active sites was prepared by thermal decomposition of the complexes containing copper and melamine. The NC−Cu catalyst exhibited an ideal current density of 22 mA cm−2 at −0.93 V versus reversible hydrogen electrode (vs. RHE) in CO2‐saturated 0.5 M KHCO3 medium, with ethanol as the predominant product at −0.93 V (vs. RHE) and a maximum Faraday efficiency of 31 %. The current density of the catalyst remained almost unchanged after 20 h of electrolysis, indicating its excellent stability. The excellent catalytic ability is attributed to the abundant Cu−N−C active sites of NC−Cu with 3D porous microstructure.

Growing MoO3-doped WO3 nanoflakes on rGO aerogel sheets towards superior microwave absorption

Nowadays, there is an urgent need for microwave absorbing materials with light weight, thin thickness, and strong absorbing ability to solve the problem of electromagnetic radiation. In this study, we report a novel high-performance aerogel absorber by growing MoO3-doped WO3 nanoflakes on reduced graphene oxide (rGO) sheets. The resultant rGO-Mo-WO3 aerogel displays a low density (∼75 mg/cm3) and unique hierarchical architectures including 3D porous microstructures, 2D rGO skeleton, and binary transition metal oxide of Mo-WO3 nanoflakes, thus leading to excellent microwave absorption performances. Typically, rGO-Mo-WO3 aerogel exhibits an ultra-strong reflection loss (RL) of −61.8 dB with a thin coating thickness of 1.54 mm. And a wide effective absorption bandwidth of 6.24 GHz can be achieved at a low filler loading of 8 wt%, much superior to previous ones. The synergistic effect of moderate polarization relaxation loss and weak conduction loss together with the porous microstructure for the aerogel result in the suitable impedance matching and strong microwave attenuation ability. This work may demonstrate a promising method to fabricate hierarchically nanostructured absorbers with the advantages of light weight, ultra-strong microwave absorption, and thin coating thickness.

Cleaner production of tamarind fruit shell into bio-mass derived porous 3D-activated carbon nanosheets by CVD technique for supercapacitor applications

This paper reported the successful preparation and characterization of bio-activated carbon nanosheets (ACNSs) synthesized from tamarind (tamarind indicia) fruits shells (TFSs) by employing Chemical Vapor Deposition (CVD) tubular furnace. The preparation of pure ACNSs and also potassium hydroxide (KOH) activated carbon nanosheets (K-ACNSs) were made through a pyrolysis process with Argon (Ar) gas as an inert gas at 800 °C for 2h 30min, followed by further purifications of K-ACNSs. The scanning electron microscope (SEM) images of ACNSs and K-ACNSs explored with and without pores respectively. The SEM micrographs also explored 3D-porous microstructure sheets with thickness around 18–65 nm. Raman spectroscopy explored crystallinity, SP2 order and graphitization at 1577–1589 cm−1. The major functional groups were also observed. The photoluminescence (PL) was analyzed for K-ACNSs materials and revealed carbon emission broad peak value at 521.3 nm. As prepared ACNSs and K-ACNSs active materials was applied for three-electrode materials of energy storage supercapacitor analysis of cyclic voltammeter for −0.4 – 0.15 V at scan rates of 10–100 mV/s. The electrochemical impedance spectroscopy (EIS) was performed with low Rct values of K-ACNSs as 0.65Ω when compared to pure ACNSs as 5.03Ω. Mainly, the galvanostatic charge-discharge test carried out in ACNSs and KCNSs materials was corresponded to 77 and 245.03 F/g respectively, with respect to 1 A/g current density. Finally, we promise that this reported novel tamarind bio-waste into conductive porous carbon nanosheets could develop future energy storage applications of biomass-derived carbons.

Development of electrical transduction based wearable tactile sensors for human vital signs monitor: Fundamentals, methodologies and applications

With the advent of advanced materials processing techniques, and physical sensors’ output data acquisition, transmission and processing by embedded systems through internet of things (IoT), artificial intelligence (AI), machine learning, etc., tools are opened up many possibilities in distributed healthcare monitor, robotic process automation, smart home, etc., domains. To further augment the efficiency of these applications wearable sensors, electronic skin, smart sensors, etc., were fabricated with a variety of materials combination. Among many sensors, temperature, pressure and volume (plethysmo) sensors are widely used in healthcare to monitor vital signs: body temperature(BT), heart rate (HR), blood pressure(BP), respiration rate (RR) and oxygen saturation (Osat). These readings are called vital signs because they all must be present for life to continue. Vital signs measurement by wearable tactile/ pressure sensors for healthcare monitor are most widely researched in the recent years due to their promising application in a distributed healthcare system. Hence, it is important to understand both the basics of vital signs and their measurement by various transduction based tactile sensors in details to devise a suitable sensor for vital signs monitor. In the literature, there are many research articles on vital signs monitor by pressure sensors with qualitative data and, some times, exaggerated claims of measurements and suitability of a sensor for specific vital sign measurement. However, for real applications one need quantitative parameters of a sensor for a particular application. Thus it may worth to separate the wheat from the chaff by studying the fundamentals of vital signs, measurement requirements and limitations of measuring techniques etc., in details. This information is missing in the literature. Hence we have systematically presented the various electrical transduction based tactile or pressure sensor technologies, sensor fabrication methods, sensor characteristics modification, basics of vital signs, and measurement techniques. The past three years literature on respective vital sign measurement were also presented here. It is inferred that the tactile sensor should be highly sensitive in linear working range of 30–190 mmHg (4–25 kPa) to measure blood pressure, heart rate and respiration rate. However, the required sensitivity value is not yet determined for each of the above measurements, in the literature. Both resistance and capacitance tactile sensors’ sensitivity and linear working range can be enhanced by employing biomimetic surface microstructures, 3D porous microstructures, intrafillable microstructures, metallic fillers, ionic liquids, etc., The details of each method is described in the article under suitable section. It is still a great challenge to simultaneously achieve high sensitivity, wide linear working range, excellent stability in a sensor for meeting the requirements of full-scale healthcare monitoring from subtle deformations (due to blood pulse, and cheek occlusion) to large deformations (due to finger bending and pressing).

Integration of Electrospray and Digital Light Processing for Freeform Patterning of Porous Microstructures

AbstractAn electrospray photolithographic patterning (EPP) process that integrates advantages of electrospray (ES) and digital light processing (DLP) for maskless fabrication of 3D porous microstructures is proposed here. First, monodisperse microparticles with controllable particle size produced by ES are deposited on a substrate to form a photoresist layer. Second, DLP exposure of the photoresist layer selectively irradiates the microparticles to form a desired pattern with complexity. Third, the repetitive steps of deposition and exposure enable layer‐by‐layer construction of a green part with embedded 3D patterns of irradiation. Finally, the irradiated microparticles are removed from the green part to form 3D particulate microstructures. With this process, freeform patterning of multiple micro‐electro‐mechanical system elements with controlled porosity, involving microfluidic channels, stamps, and power‐free pressure sensors is successfully demonstrated. The EPP process has a great technical potential for freeform and high‐throughput fabrication of multi‐layered porous microstructures in versatile applications such as micromixers, porous stamping, and microsensors.

Pseudocapacitive Lithium Storage in Three‐Dimensional Cobalt‐Doped MnO/Nitrogen‐Doped Reduced Graphene Oxide Aerogels as High‐Rate Anode Material

AbstractStructural design and modification are effective measures to improve the lithium storage performance of electrode materials. Herein, three‐dimensional (3D) porous Co‐doped MnO/nitrogen‐doped reduced graphene oxide aerogels (Co−MnO/NG‐G) have been prepared by successive self‐assembly processes, including the self‐assembly nucleation of Co−MnO on GO in H2O/N,N‐Dimethylformamide (DMF) mixed solvent, and the 3D reduction‐assembly of hydrogels accompanied with nucleation‐inducing growth of Co−MnO nanocrystals. Due to high‐efficient electron/ion transport channels dating from the novel 3D porous microstructure and improved electron/ion conductivity deriving from doping MnO with Co, the 3D Co−MnO/NG‐G electrode demonstrates high pseudocapacitive lithium storage behavior with 88.3 % at 2 mV s−1. As an anode in lithium‐ion battery, the 3D Co−MnO/NG‐G shows a high capacity of 982.8 mAh g−1 at 0.5 A g−1 after 100 cycles, outstanding rate capability with 424.0 mAh g−1 at 8 A g−1, as well as superior cycle stability with 508.9 mAh g−1 after 800 cycles at 4 A g−1. This work demonstrates that the synergistic strategy between cation doping and 3D porous channels for electron/ion transport is an effective way to design high‐rate anode materials.

Nitrogen-doped porous 3D graphene with enhanced supercapacitor properties

Nitrogen-doped graphene has attracted increasing attention in recent years. Synthesis of nitrogen-doped 3D graphene with high capacitance and excellent capacitive behavior is highly desirable for high-performance supercapacitor applications. In this study, nitrogen-doped porous 3D graphene was prepared from graphite oxide using the mild one-pot hydrothermal procedure. The p-phenylenediamine and ammonia were selected as the reduction and doping agents, respectively. 3D graphene specimens with various nitrogen doping amounts of 6.52–7.81% were prepared. Scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction and supercapacitor performance were used to investigate the morphologies, structures and capacitance behaviors of the prepared 3D graphene composites. The results indicated that the as-prepared specimens contained different doping nitrogen amounts. NGP-10.6 showed well-connected 3D porous microstructure with largest doping nitrogen content. In turn, nature and content of nitrogen doping provided the graphene with excellent capacitive behavior. The specific capacitance of NGP-10.6 reached 788 F·g−1 at the current density of 0.5 A·g−1 and 296 F·g−1 at 10 A·g−1. Overall, these findings look promising for future applications as outstanding energy storage materials.

Two-Wavelength, Photo-Initiation and Photo-Inhibition Competing for Selective Photo-Patterning of Hydrogel Porous Microstructures

Ever since its development, tissue engineering has played a significant role in the medical arena with an ever-growing demand for various tissue donations. One crucial factor in conducting in vitro tissue engineering study is the construction of a desirable artificial three-dimensional (3D) hydrogel tissue scaffold to act as the extracellular matrix (ECM), meeting the complex requirements for specific cell cultures. Existing hydrogel scaffold fabrication techniques and systems utilized in constructing ECM are either twodimensionally limiting, hard to control the pattern morphologies or expensive and time consuming. In the present study, we introduce a simple, inexpensive method for selective patterning 3D porous microstructures. This technique-'two wavelength photo-initiation and photo inhibition competes’ is an extension of conventional photo-patterning method. Integrating with shadow mask, photo inhibition radicals were introduced to couple with the polymerization chains and terminate the photo crosslinking behavior at designed region, making 3D selectively patterning hydrogel feasible. High aspect ratio ridge with selectively inhibited porous structures and selectively patterned micro pillar were fabricated using this method within 1 minute. The in vitro cell test results indicate the patterned structures' good biocompatibility.

Evolution of structure and functional groups in the functionalization of graphene oxide with L-cysteine

A one-step method is proposed to fabricate three-dimensional functionalized graphene oxide (3D GOL) using L-cysteine (L-Cys) as grafting modification agent under atmospheric pressure. The emphasis is determining the functional modification mechanism of 3D GOL with characterization of morphology, structure and functional groups through scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The results showed that 3D GOL has a well-connected 3D porous microstructure. With the increase of mass ratio of L-Cys to graphene oxide (GOs), more pores in the microstructure of 3D GOL were formed and the pore size got smaller. The reactions between L-Cys and GOs, such as oxidation-reduction reaction of sulfhydryl with hydroxyl groups, dehydration of sulfhydryl with carboxyl groups, and amidation reaction of amino with carboxyl groups promoted the crosslinking of GOs nanosheets, and induced the GOs nanosheets to assemble into a 3D porous framework.

3D Porous MXene (Ti3C2)/Reduced Graphene Oxide Hybrid Films for Advanced Lithium Storage.

MXenes, as a new family of 2D materials, can be used as film electrodes in energy storage devices because of their hydrophilic surface, metallic conductivity, and rich surface chemistries. However, the poor ion transport of MXene film electrodes causes a great loss of surface reactivity, which significantly inhibits the full exploitation of the potential of MXene-based materials. To solve this issue, we report a facile electrolyte-induced self-assembly method to construct a 3D porous structure in the MXene-rGO hybrid film, which effectively facilitates rapid diffusion and transport of electrolyte ions in the film electrode while still maintaining high electrical conductivity. When the hybrid film is employed as electrode materials for lithium-ion batteries, it exhibits high specific capacity of 335.5 mA h g-1 at 0.05 A g-1 and good rate capability of 30% capacitance retention at 4 A g-1. Additionally, the film electrode exhibits excellent cycling stability without capacity decay after 1000 cycles under high rates (1 A g-1) owing to its stable structure. Furthermore, the electrochemical analysis also demonstrates that the novel 3D porous microstructure plays an important role in the fast reaction kinetics and high capacity of the MXene-rGO hybrid film electrode. This work may provide a new strategy to solve the issues related to poor ionic transport in MXene-based film electrodes.

Development of biocompatible glycodynameric hydrogels joining two natural motifs by dynamic constitutional chemistry

The paper focusses on the synthesis of novel hydrogels by joining natural biodegradable compounds with the aim to achieve biocompatible materials for bio related applications. The hydrogels were prepared from chitosan and citral by constitutional dynamic chemistry, incorporating both molecular and supramolecular dynamic features. The hydrophobic flexible citral has been reversible immobilized onto the hydrophilic chitosan backbone via imine bonds to form amphiphilic glycodynamers, which further self-ordered through supramolecular interactions into a 3D-network of biodynameric hydrogel. The synthetic pathway has been demonstrated by NMR and FTIR spectroscopy, X-ray diffraction and polarized light microscopy. Studies of the hydrogel morphology revealed a 3D porous microstructure, whose pores size correlated with the crosslinking degree. Rheological investigations evidenced high elasticity, thermo-responsiveness and thixotropic behavior. As a proof of the concept, the hydrogels proved in vivo biocompatibility on laboratory mice. The paper successfully implements the constitutional dynamic chemistry in generation of chitosan high performance hydrogels.

An efficient supercapacitor of three-dimensional MnO2 film prepared by chemical bath method

MnO2 film is directly grown on Ni foam substrate by a facile chemical bath deposition method. The microstructure characterization of as-prepared MnO2 film is conducted by SEM, XRD and nitrogen adsorption and desorption measurements. The β-MnO2 film consists of a large number of round nanoplatelets cross-linked with each other and forms 3D porous microstructure with a BET area of 80.6 m2 g−1 and an average pore diameter of 3.8 nm. The electrochemical performance of MnO2 film electrode is investigated by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge/discharge measurements. The obtained MnO2 film electrode without binder additive shows excellent pseudocapacitance behavior, delivering the maximum capacitance of 1517 F g−1 in KOH and 546 F g−1 in KNO3 at a current density of 1 A g−1. This study provides a facile method for preparation of three-dimensional MnO2 film with efficient supercapacitive properties.

Excellent anti-corrosive pretreatment layer on iron substrate based on three-dimensional porous phytic acid/silane hybrid.

A novel, highly effective and environmentally friendly film-forming material, phytic acid (PA)/silane (denoted as PAS) hybrid with a three-dimensional (3D) network structure, was prepared through a condensation reaction of PA with methyltrihydroxysilane generated from the hydrolysis of methyltriethoxysilane (MTES). Two kinds of PAS-based pretreatment layers, namely NaBrO3-free and NaBrO3-doped PAS layers, were fabricated on iron substrates using the dip-coating method. SEM and AFM observations showed that the as-fabricated PAS-based layers possessed a 3D porous microstructure at the nanoscale and a rough surface morphology. X-ray photoelectron spectroscopic (XPS) and attenuated total reflection infrared (ATR-IR) spectroscopic characterization demonstrated that the above PAS layers bound to the iron surface via the -P-O- bond. Moreover, analyses of steady-state polarization curves and electrochemical impedance spectroscopic (EIS) data indicated that the corrosion rates of the iron substrates decreased considerably in the presence of the two PAS-based pretreatment layers. In particular, the NaBrO3-dosed PAS layer displayed the better corrosion resistance ability as well as maintaining the original microstructure and surface morphology. The PAS-based pretreatment layers are expected to act as substitutes for chromate and phosphate conversion layers and will find widespread application in the surface pretreatment of iron and steel materials due to the advantages of being environmentally friendly, the rapid film-forming process, and, especially, the nanoporous microstructure and rough surface morphology.

Synthesis and Gas-Sensing Properties of ZnO Porous Microflowers

Three-dimensional (3D) porous nanomaterials with large surface area and abundant surface defects have promis- ing potential in gas sensing due to the following merits: (i) large contact area of gaseous species with the materials, and more adsorption sites on the highly defective surface, (ii) good accessibility to gaseous species of the 3D open structure, (iii) fast electron transport among the 3D network. Rational design and controlled synthesis of the 3D porous nanomaterials with spe- cific morphology and microstructure are essential for improving the performance of gas sensing. In this work, 3D ZnO po- rous microflowers were prepared by directly calcining the zinc-based flowerlike precursor at 400 ℃ in air. The precursor was preformed through a simple coprecipitation method, i.e., by refluxing the aqueous solution of zinc nitrate and co-precipitators of hexamethylenetetramine and oxalic acid at 90 ℃ for 4 h. The unique ZnO porous microflowers were composed of porous nanosheets of 10~50 nanometers in thickness and 1~2 micrometers in width, which inherited from the zinc-based precursor except for the randomly distributed pores on the nanosheet "petals". The 3D porous microstructures endowed ZnO with large specific surface area of 31.3 m 2 •g -1 and abundant surface defects. ZnO porous microflowers were used as active materials to fabricate gas sensors, which exhibited low working temperature, high sensitivity and fast response (recovery) characteristic against ethanol vapor, at the advanced level in comparison with the reported ZnO-based gas sensors for ethanol. The superior performance of the gas sensors could be attributed to the unique microstructures of the ZnO porous nanomaterials. In addition, the sensitivity of the gas sensors showed an exponential relationship with the concentration of ethanol vapor, indicating their capability of quantitative detection within the ethanol volume ratio of 1×10 -6 ~500×10 -6 .

Efficient 3D porous microstructure reconstruction via Gaussian random field and hybrid optimization

Obtaining an accurate three-dimensional (3D) structure of a porous microstructure is important for assessing the material properties based on finite element analysis. Whereas directly obtaining 3D images of the microstructure is impractical under many circumstances, two sets of methods have been developed in literature to generate (reconstruct) 3D microstructure from its 2D images: one characterizes the microstructure based on certain statistical descriptors, typically two-point correlation function and cluster correlation function, and then performs an optimization process to build a 3D structure that matches those statistical descriptors; the other method models the microstructure using stochastic models like a Gaussian random field and generates a 3D structure directly from the function. The former obtains a relatively accurate 3D microstructure, but computationally the optimization process can be very intensive, especially for problems with large image size; the latter generates a 3D microstructure quickly but sacrifices the accuracy due to issues in numerical implementations. A hybrid optimization approach of modelling the 3D porous microstructure of random isotropic two-phase materials is proposed in this paper, which combines the two sets of methods and hence maintains the accuracy of the correlation-based method with improved efficiency. The proposed technique is verified for 3D reconstructions based on silica polymer composite images with different volume fractions. A comparison of the reconstructed microstructures and the optimization histories for both the original correlation-based method and our hybrid approach demonstrates the improved efficiency of the approach.

Fabrication and characterization of gelatin‐based biocompatible porous composite scaffold for bone tissue engineering

In this study, composite scaffolds were prepared with polyethylene oxide (PEO)-linked gelatin and tricalcium phosphate (TCP). Chitosan, a positively charged polysaccharide, was introduced into the scaffolds to improve the properties of the artificial bone matrix. The chemical and thermal properties of composite scaffolds were investigated by Fourier transform infrared spectroscopy, thermogravimetric analyzer, differential thermal analyzer. In vitro cytotoxicity of the composite scaffold was also evaluated and the sample showed no cytotoxic effect. The morphology was studied by SEM and light microscopy. It was observed that the prepared scaffold had an open interconnected porous structure with pore size of 230-354 μm, which is suitable for osteoblast cell proliferation. The mechanical properties were assessed and it was found that the composite had compressive modulus of 1200 MPa with a strength of 5.2 MPa and bending modulus of 250 MPa having strength of 12.3 MPa. The porosity and apparent density were calculated and it was found that the incorporation of TCP can reduce the porosity and water absorption. It was revealed from the study that the composite had a 3D porous microstructure and TCP particles were dispersed evenly among the crosslinked gelatin/chitosan scaffold.