Pore Morphology Research Articles

Fabrication of micro-porous polymeric coating with dynamic drug-eluting property on plastic biliary stent for antiproliferative treatment

The current study aims to construct additional drug-eluting carrier for commercially available biliary stent, providing a practical strategy for the cost-efficient treatment of benign biliary stricture. Specifically, the commercially available biliary stent was endowed with porous polylactic acid coating via in-situ pore-formation induced by solvent treatment. The drug-eluting stent with fibroblast inhibition effect was successfully established by efficiently loading the antiproliferative drug of triamcinolone acetonide into the porous coating. The drug release behavior could be dynamically controlled by adjusting the pore morphology of the porous coating. The in-vitro coating degradation and the fibroblast inhibition effect of the drug-eluting stents were further evaluated to prove the effectiveness of the fabricated porous coating as an antiproliferative drug carrier.

Polyacrylonitrile‒Chitosan IPN composite scaffolds that closely mimic the human trabecular bone structure for tissue engineering

Successful bone tissue engineering involves managing several important parameters, such as the design of intercommunicating porous structures, pore sizes, and the material and mechanical suitability of the material. In our work, we focused on the preparation of a synthetic scaffold that morphologically mimics the structure of human trabecular bone. The scaffolds were fabricated through the thermal modification (TM) of polyacrylonitrile. The scaffold strength was supported by a crosslinked chitosan supporting network. The prepared scaffold has imprinted pores of the appropriate size to facilitate the ingrowth and proliferation of human osteoblasts throughout the entire pore volume created by a primary porogen, sodium chloride. The resulting material has a dual porous morphological structure, in which adjustable larger pores support cellular ingrowth into the scaffold, whereas smaller pores, created using succinonitrile (SCN) as a secondary porogen, increase the diffusion of oxygen and nutrients to developing cells. The mechanical properties of the scaffold were promoted by the use of a secondary interpenetrating network (IPN) based on chitosan. The incorporation of secondary IPNs led to a significant improvement in the mechanical characteristics of the scaffold. Two crosslinking agents were used: the widely utilized glutaraldehyde (GA) and its green, nontoxic alternative, genipin (GEN).The current study introduces a synthetic scaffold that effectively mimics the structure of human trabecular bone, providing a conducive environment for osteoblast proliferation and ingrowth. We incorporated a dual porous morphology and a secondary IPN based on chitosan and found that the scaffold exhibited improved mechanical properties and nutrient diffusion capabilities. This research highlights the potential of these scaffolds for major advancements in bone tissue engineering, demonstrating their noncytotoxic nature and ability to support the adhesion and proliferation of the human osteosarcoma cell line SAOS-2. The described scaffold preparation technique may offer distinct advantages over current high-end methods such as 3D printing. The primary benefit lies in its very simple instrumentation, which enables the creation of a complex trabecular bone morphology with both macro- and microporosity in the bulk, which is still challenging for common 3D printers. Additionally, IPN with chitosan can be postmodified, substantially expanding the potential applications of these scaffolds.

Modeling 2,4-dichlorophenoxyacetic acid adsorption on candle bush pod-derived activated carbon: Insights from advanced statistical physics models

The widespread usage of 2,4-Dichlorophenoxyacetic acid (2,4-D) as an herbicide has led to alarming levels of environmental pollution, presenting severe risks to ecosystems and human health. This study aimed to synthesize a new adsorbent, activated carbon from candle bush pods (CBAC) via low-temperature phosphoric acid activation and investigate its ability for adsorptive elimination of 2,4-D. The setup of a new adsorption system requires the experimental determination of adsorption isotherms and their thorough modeling, which is achieved through advanced statistical physics models (ASPMs). The characterization of CBAC revealed a porous morphology with a remarkable specific surface area (415.31 m2/g). XRD revealed graphitic carbon structures, while XPS detected phosphate groups, graphitic structures, and oxygen-containing functional groups. Double layer with single energy (DLSE) model – one of the ASPMs revealed both non-parallel and parallel orientation of 2,4-D molecules on CBAC, with saturation adsorption capacity values increasing with temperature (up to 252.35 mg/g) at pH 2. The adsorption was physisorption (ΔE = 12.62–16.26 kJ/mol) and spontaneous and endothermic. Hence, the findings herein demonstrate the potential of CBAC as a sustainable and effective adsorbent for mitigating environmental pollution caused by 2,4-D.

Conformal coating of PbO2 around boron doped diamond coated carbon felt positive electrode for stable and high-capacity operation of soluble lead redox flow battery

The commercialization of soluble lead redox flow battery (SLRFB) is challenging due to its limited cycle life, lower areal capacity, Pb dendrite formation, and positive electrode corrosion. However, improvements are made to a certain extent by employing additives chemistry in terms of electrolyte modification. One of the major problems in SLRFB is carbon corrosion at higher current densities. Therefore, electrode modification, specifically on the positive side, is required to improve the cyclability of SLRFB further. There is minimal literature on this aspect.Given this, efforts are being made to enhance the electrochemical performance of SLRFB by employing a boron doped diamond (BDD) coated carbon felt (CF) as the positive electrode. The BDD coated CF electrode possesses a high surface area (7.1 m2g−1) compared to bare CF (0.6 m2g−1), i.e., BDD creates porous morphology, which enables a high mass transfer and hence reduces concentration polarisation. BDD coating on the CF delays the OER and reduces the overpotential for PbO2 deposition/dissolution. The cell with BDD coated CF electrode is successfully cycled for >300 charge/discharge cycles @ 40 mA cm−2 with average coulombic efficiency (CE), voltage efficiency (VE) and energy efficiency (EE) of 97 %, 71 % and 69 % respectively. The EE is improved by 8 % in the presence of BDD coated CF as compared to CF electrode. SLRFB cell with BDD coated CF electrode has reached 80 mAh cm−2 areal capacity.

Sponge-like tungsten phosphide-ruthenium constructed by ultrafast quasi-solid state microwave for wide pH hydrogen generation

Transition metal phosphides (TMPs) are typical of emerging hydrogen evolution reaction (HER) catalysts, but tedious synthesis approach limits its practical applications. Herein, sponge-like tungsten phosphide with ruthenium (Ru/WP) is synthesized by a simple and rapid (20 s) quasi-solid state microwave approach. The synthesized Ru/WP possesses porous morphology with rich interconnected channels to accelerate the energy transport and expose ample active sites. In addition, the strong electronic interactions promote the reaction kinetics between Ru and WP. Thus, the prepared Ru/WP owns excellent catalytic activity in alkaline freshwater/seawater, acid and neutral electrolyters, with low overpotentials of 36/24, 48, and 69 mV to provide 10 mA cm−2 for HER. In alkaline electrolyte, the overall water decomposition requires only 1.57 V to reach 10 mA cm−2 with satisfactory stability. The rapid microwave quasi-solid state synthesis strategy provides a novel direction for developing metal phosphides in the energy sector.

Feature size specific processing parameters for additively manufactured Ti-6Al-4V micro-strut lattices

The material properties of individual micro-struts are critical to the overall success of lattice structures. These properties can be significantly compromised by defects inherited from powder bed fusion processes. Among these defects, porous inclusions are well understood to have a detrimental effect on mechanical properties; posing a high risk to the implant under loading. While the majority of these defects can be avoided through optimisation of printing parameters, this has generally only been done for traditional bulk components with no in-designed porosity. Furthermore, a number of studies have observed changes in the frequency of such porous inclusions as feature size is reduced, indicating a size effect. This also suggests that the optimal parameters for bulk material are not necessarily translatable to the individual micro-struts which build the lattice. In this study, the relationship between parameter optimisation and feature size was investigated. Here, a higher energy density input was required for processing micro-strut lattices with an optimised relative density, than it was for bulk components. This could be attributed to faster rates of heat loss in micro-strut samples on account of their increased surface-to-volume ratio. The consequential improvement in mechanical properties was also assessed. An increase in both strength and stiffness could be largely attributed to an increase in the percentage volume of load bearing material, while improvements in failure strain were largely driven by minimisation of stress concentrations around the irregular pore morphologies. Fatigue properties did not improve beyond the effects of yielding. Rather, crack initiation was dominated by surface defects; which on account of their surface free energy, experience a much higher stress intensity factor.

Optimal design and performance evaluation of grinding wheels with triply periodic minimal surface lattice structure

High-performance grinding wheels are critical tools for precision surface generation. In precision grinding processes, the coolant supply at the wheel-workpiece interface is critical for reducing grinding temperature and detrimental friction. For better lubrication and chip removal performance, the cavities or pores need to be generated throughout the grinding wheel. The ideal morphology of pores in grinding wheels should be inter-connected and capable of providing sufficient coolant. Conventional grinding wheel design and fabrication methods can only passively generate closed circular pores by using pore-forming agents. Increasing the percentage of pores in this way generally leads to an uncontrollable reduction in mechanical strength, while the closed pores are insufficient in cooling performance. In this paper, the grinding wheels with triply periodic minimal surface lattice structure are designed and fabricated, which achieves the regulable and inter-connected internal structure of grinding wheels. Meanwhile, to balance the relationship between the structural properties and performance indicators of porous grinding wheels, an optimal design method for the porous structure of grinding wheels is proposed. Finally, the grinding performance of the novel grinding wheels in comparison to electroplated diamond grinding wheels is investigated in terms of grinding force, specific grinding energy and ground surface roughness.

Superfine grinding combined with enzymatic modification of pea dietary fibre: Structures, physicochemical properties, hypoglycaemic functional properties, and antioxidant activities

N-SDF, S-SDF, E-SDF, and SE-SDF were extracted from natural pea dietary fibre (DF) and modified pea DF by superfine grinding (S), enzymatic modification (E), and superfine grinding combined with enzymatic modification (SE). The structures, physicochemical properties, hypoglycaemic functional properties, and antioxidant activities of the three types of modified SDF were compared with those of natural N-SDF. The results showed that the four SDF types had similar infrared spectra and monosaccharide compositions, whereas their main functional groups, binding degree, and monosaccharide content were different. The molecular weights of S-SDF and SE-SDF decreased compared to that of natural N-SDF, whereas that of E-SDF increased. The microstructure of SE-SDF showed the softest, roughest, and most porous morphology compared with those of the other three SDF types. The hypoglycaemic functional properties (glucose adsorption capacity, glucose dialysis retardation index, and α-amylase inhibition rate) of the three modified SDF types were improved compared with the natural N-SDF. Moreover, SE-SDF had the best effect. In addition, the DPPH· scavenging ability, reducing power, and ·OH scavenging ability of S-SDF and SE-SDF were improved compared with those of natural N-SDF. Remarkably, all four SDF types exhibited excellent ABTS· scavenging ability at a concentration of 0.6 mg/mL. Consequently, SE-SDF holds promise as an outstanding food additive for reducing postprandial blood glucose levels, enhancing antioxidant activities, and mitigating oxidative damage.

Tailoring thermal conductivity and microstructure of Al–Fe alloys by addition of Sc2O3 and variable cooling rates

Al–Fe alloy is a kind of high thermal conductivity alloy, which are widely utilized in the communication and automobile industries. The thermal conductivity is greatly affected by the morphology, size, and distribution of iron-rich intermetallic phases (Fe-rich phases), pores, and Al grains. The evolution of microstructure and thermal conductivity of Al–Fe alloys by adding Sc2O3 particles and adjusting cooling rates are systematically studied by optical and scanning electron microscopy, and synchrotron X-ray imaging. The results show that Sc2O3 addition reduces the size and increases the number of primary Fe-rich phases, while increasing the grain size of Al matrix. The Sc2O3 promote their nucleation of primary Fe-rich phases and partial Sc solutes inhibit their growth, resulting in the improvement of thermal conductivity and mechanical properties. The remaining Sc2O3 particles have large lattice misfit with Al, led to the formation of coarsen size Al. The highest thermal conductivity is 214 W/(m·K) in the alloy with Sc2O3 and slow cooling rate. Sc2O3 addition increase the thermal conductivity of the studied alloys, i.e., an increment of 3 W/(m K) (by 1.1 %) at slow cooling rate by and an increment of 11 W/(m K) (by 6.2 %) at fast cooling rate. This study provides a new strategy to improving thermal conductivity of Al alloy for both academia and industry.

Evolution of pore structure and diagenetic stages of late Permian shales in the Lower Yangtze Region, South China

This study examines the evolution characteristics of shale pores in the Late Permian Longtan Formation located in the Lower Yangtze region of South China. The complete process of thermal evolution of the samples was achieved through thermal simulation experiments while identifying qualitatively the pore types and their development characteristics using field emission-scanning electron microscope (FE-SEM). Quantitative analysis of pore size distribution was conducted through mercury intrusion capillary pressure (MICP), nitrogen (N2) and carbon dioxide (CO2) adsorption experiments. The paper comprehensively analyzed the pore evolution characteristics and controlling factors of shale in the study area, with an analysis of diagenetic differences. Findings reveal that during the pore evolution process, both morphology and pore size are influenced by thermal maturity. The pore volume is dominated by mesopores and macropores, while the specific surface area is mainly dominated by mesopores and micropores. Thermal evolution promotes the formation of micropores and mesopores but hinders the development of macropores. Moreover, clay minerals transformation and mineral dissolution make certain contributions to the development of micropores. The diagenesis in the study area is controlled primarily by the pyrolysis of organic matter. Pyrite and clay minerals are the first to dissolve, followed by calcite and quartz. Five stages of evolution characterization have been identified from low-mature stage (Ro = 0.88 %) to overmature stage (Ro = 3.35 %) in combination with diagenesis. The development of pore structure and its influencing factors vary across different stages. The influencing factors mainly include hydrocarbon generation from organic matter, compaction, mineral transformation, and dissolution. The process of hydrocarbon generation in organic matter occurs throughout the entire pore evolution process, resulting in the development of numerous micropores and mesopores. Compaction primarily impacts pore development during the early diagenetic stage, causing a substantial transition of primary mineral pores from macropores to mesopores. Mineral transformation and dissolution take place during and after the middle diagenetic stage. The former governs the development of mesopore-sized clay interlayer pores, while the latter primarily generates micropores.

Ultrafast Quasi-Solid-State Microwave Construction of Spongy Cobalt-Molybdenum Phosphide for Hydrogen Production Over Wide pH Range.

The developed strategies for synthesizing metal phosphides are usually cumbersome and pollute the environment. In this work, an ultrafast (30s) quasi-solid-state microwave approach is developed to construct cobalt-molybdenum phosphide decorated with Ru (Ru/CoxP-MoP) featured porous morphology with interconnected channels. The specific nanostructure favors mass transport, such as electrolyte bubbles transfer and exposing rich active sites. Moreover, the coupling effects between metallic elements, especially the decorated Ru, also act as a pivotal role on enhancing the electrocatalytic performance. Benefiting from the effects of composition and specific nanostructure, the prepared Ru/CoxP-MoP exhibits efficient HER performance with a current density of 10mAcm-2 achieved in 1m KOH, 0.5mH2SO4, seawater containing 1mKOH and 1mPBS, with overpotentials of 52, 59, 55, 90mV, and coupling with good stability. This work opens a novel and fast avenue to design metal-phosphide-based nanomaterials in energy-conversion and storage fields.

Sustainable heavy metal (Cr(VI) ion) remediation: Ternary blend approach with chitosan, carboxymethyl cellulose, and bioactive glass

Heavy metal pollution poses a significant environmental challenge to worldwide, especially in developing countries. This study focuses on eliminating the heavy metal chromium (VI) ion from wastewater, employing an eco-friendly and economical ternary blend composed of Chitosan (CS), Carboxymethyl cellulose (CMC), and bioactive glass (BAG). The innovative bioactive glass is crafted from biosilica extracted from biowaste of cow dung ash, calcium oxide from eggshell ash, and phosphorus pentoxide. The CS/CMC/BAG blend is prepared via sol-gel method and characterized using XRD, FT-IR, TGA, BET, TEM and SEM revealing a porous structural morphology during blending. Batch adsorption studies explore various parameters such as pH, adsorbent dose, contact time and initial metal ion concentrations. The results are then evaluated through adsorption kinetics and adsorption isotherms (Langmuir, Freundlich, D-R, and Temkin isotherm modeling). The investigation concludes that the optimal conditions for Cr (VI) removal are pH 3, contact time of 300 min, adsorbent dosage of 0.5 g, and an initial metal ion concentration of 50 ppm. The adsorption isotherm model indicates an excellent fit with the Freundlich isotherm (R2 = 0.9576) and pseudo-second-order kinetics (R2 = 0.981). In summary, the CS/CMC/BAG ternary blend exhibits a remarkable ability to effectively remove heavy metal Cr(VI) ions from industrial wastewater.

Analysis of mechanical properties and deterioration mechanisms of mudstone under wetting-drying cycles

During seasonal rainfall periods, natural rocks typically undergo repeated wetting-drying cycles, which directly affects the micro-structure of the rock samples and consequently leads to the deterioration of their mechanical properties, especially in mudstone. Therefore, this paper investigated the degradation pattern of strength parameters and failure pattern of mudstone samples under wetting-drying cycles through a series of laboratory tests and quantitatively characterized the micro-structural changes in the samples. Additionally, numerical simulations were utilized to delve deeper into the degradation mechanism of the samples. The results indicate that with an increasing number of wetting-drying cycles, the degradation of peak strength and elastic modulus becomes more pronounced. Moreover, there is a continuous increase in micro-porosity within the samples, accompanied by changes in pore structure and morphology. According to the simulation results, the wetting-drying cycles change how the samples fail, transitioning from mixed tensile-shear failure to predominantly shear failure. This study not only deepens the theoretical understanding of the deterioration mechanisms in mudstone but also provides important guidance for practical applications.

Fabrication of Zinc Doped Titanium Dioxide Nanoparticles to Inhibit Escherichia coli Growth and Proliferation of Liver Cancer Cells (HepG2).

The current research is related to the synthesis of different concentrations (0, 3, and 7 wt %) Zn doped TiO2-NPs by using the coprecipitation method. The rutile, anatase crystal structure appeared on different diffracted peaks in TiO2-NPs, and the crystallite size (12 to 24 nm) was calculated by using XRD analysis. The spherical, irregular, porous grain-like surface morphology was observed by SEM analysis, and the identification of different functional modes such as hydroxyl, -C-O, -C-O-C, and Ti-O-Ti attached on the surface of the spectrum was examined via FTIR analysis. After that, the increased absorbance of TiO2-NPs by increasing the Zn concentration in TiO2-NPs was observed by UV-visible analysis. After that, the well diffusion method was performed to measure antibacterial activity, and the MTT assay was used to investigate anticancer activity against the HepG2 cell line. It was observed that the inhibition zone of S. aureus and E. coli increased by increasing the concentration of Zn-doped TiO2-NPs from 2 to 32 mm. The 7 wt % Zn-doped TiO2-NPs provided significant anticancer activity against the liver cancer cell line and antibacterial activity. In the future, Zn doped TiO2-NPs can be used for in vitro analysis against different microbial and animal models for the treatment of cancer.

One-pot synthesis of tungsten oxynitride/nitrogen-doped graphene with particle-sheet hybrid nanostructure as a highly effective binder-free supercapacitor electrode

High-performance nanoscale composites have achieved predominance as promising materials for supercapacitor applications. Graphene nanosheets decorated with transition metal oxynitride nanoparticles can be highly beneficial in improving supercapacitor properties. However, they are hardly retrieved, and their electrochemical characterizations and inherent charge-storage mechanisms have not been deeply investigated. Herein, tungsten oxynitride decorated nitrogen-doped graphene (WON-NG) is synthesized by a facile one-pot strategy in a particle-sheet hybrid nanostructure. The nanocomposite is grown directly on a nickel foam (NF) as the current collector through the synthesis process. X-ray photoelectron spectroscopy and TEM images have confirmed the particle-sheet hybrid nanostructure of the prepared nanocomposite with tungsten oxynitride nanoparticles and nitrogen-doped graphene nanosheet. The oxygen and nitrogen-based redox groups, which synergistically coexist in the hybrid network, inherently cooperate in the electrochemical activities of the nanocomposite. The electrochemical measurements show that the WON-NG|NF electrode can deliver a superior specific capacitance of 1079.4 F g−1 (4.6 F cm−2) at 1 A g−1 in 1 M KOH aqueous electrolyte. In-depth investigations suggest that the diffusive-controlled process governs the charge storage mechanism at all scan rates in the composite for the advantageous porous morphology. The assembled all-solid-state asymmetric supercapacitor device exhibits a high energy density of 81.6 Wh kg−1 and a power density of 5005.4 W kg−1. Also, the designed devise shows an excellent cycle life with 87.7% capacitance retention of 10,000 cycles.

High-performance cellulose-based nanostructured carbons for rechargeable batteries

Binder-free, highly porous carbon nanofibers (CNFs) with novel sponge-like pore structures were synthesized for the first time via centrifugal spinning of cellulose-based polymers, and SnO2 was introduced to improve the electrochemical performance. Cellulose-based binder-free centrifugally spun carbon-coated SnO2/carbon nanofibers (C@SnO2/CNFs) were employed as anodes in Na-ion batteries. Owing to their highly porous morphology with novel sponge-like pore structures and SnO2 nanoparticles providing rapid Na-ion transport, better electrolyte accessibility, and good mechanical strength, the C@SnO2/CNFs showed outstanding electrochemical performance, with a high reversible capacity of 660 mAh/g at 50 mA/g, high rate capability, and excellent cycling performance. The specific capacity of C@SnO2/CNFs was approximately 390 mAh/g after 2000 cycles at 0.2 A/g. These results prove that the combination of centrifugal spinning, carbon coating, and heat treatment is a promising and sustainable approach for creating cellulose-based carbon nanostructures with highly porous structures that can be used to synthesize high-performance electrodes for energy storage systems.

Synthesis and characterization of hierarchically porous carbon anodes from furfural biorefinery residues for sustainable lithium-ion batteries

This study aims to valorize abundant lignocellulosic residues from furfural biorefineries into hierarchically porous carbon anodes for sustainable lithium-ion batteries (LIBs). Simultaneously, it addresses the growing demand for high-performance anode materials by leveraging renewable waste feedstocks. Sugarcane bagasse waste residues obtained after furfural extraction were used as the precursor. The furfural-derived bagasse residue (FDBR) underwent pyrolysis at 700 °C to produce a carbon-rich char, which was further activated using KOH and steam at 900 °C for 15–60 minutes to enhance porosity development. Comprehensive physicochemical characterizations, including proximate analysis, N2 adsorption-desorption, SEM-EDX, FTIR, and TGA/DTG, and Raman spectroscopy were performed to evaluate the properties of the synthesized activated carbons. The results demonstrated the successful generation of high surface area (405.8 m2/g) activated carbons with a hierarchical pore structure comprising micropores and mesopores. SEM and EDX analyses revealed a uniform, porous morphology enriched with 10.41 % at oxygen-containing functional groups. FTIR spectra confirmed the presence of hydroxyls, carbonyls, and carboxylic acid groups, beneficial for pseudocapacitive charge storage. The Raman analysis revealed a highly disordered and amorphous carbon structure with a significant concentration of defects, as evidenced by a high-intensity ratio (ID/IG ≈ 1.2–1.4) of the disordered carbon band to the graphitic band. The activated carbons exhibited a high initial discharge capacity of 1055 mAh/g in lithium half-cells, significantly exceeding the theoretical limit of commercial graphite anodes (372 mAh/g). This superior capacity was attributed to the high surface area, hierarchical porosity, and pseudocapacitive contributions from the oxygen functionalities. However, rapid capacity fading from 1055 to ∼250 mAh/g was observed over 100 cycles at a C/2 rate. The capacity retention stabilized at ∼88 % after 47 cycles, indicating irreversible capacity losses. These limitations were ascribed to the disordered amorphous structure, instability of the solid-electrolyte interphase, lithium trapping by oxygen groups, and structural changes during cycling. Optimizing activation conditions, incorporating conductive additives/coatings, exploring alternative binders, and surface functionalization are proposed to improve long-term cycling stability. Overall, this study demonstrates the feasibility of upcycling furfural biorefinery waste into sustainable LIB anodes while highlighting challenges and potential solutions for enhancing their electrochemical performance.

(Invited) Organic Electrochemical Bioelectronic Devices Based on 3D Conductive Polymer Scaffolds

The integration of 3D tissue-engineered microporous scaffolds based on conductive polymers (CPs) into bioelectronic devices have led to the possibility of dynamic monitoring of biological phenomena through electrical measurements. The 3D structure and morphology of the porous scaffolds mimics the topographical features of human physiology, while the electrically conductive nature of the polymers allows for electrical measurements for label-free monitoring and live-sensing of cells. 3D scaffolds based on the polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) prepared by the freeze drying process have been the focus of many studies and well integrated into bioelectronic devices such as electrodes[1] and organic electrochemical transistors[2].The influence of the different protocols and freezing rates on the pore size and structure was examined by scanning electron microscopy and micro computed tomography. Pores of circular and elongated ellipses were observed by SEM and a pore size distribution (the longest dimension of the ellipsoid) between 80 µm and 220 µm was measured. It was observed that a higher cooling rate generated larger pores with more elongated pore morphology as well as a wider pore size distribution. The pre-cooling treatment with 0.5°C/min cooling rate was most useful in generating scaffolds with a more homogenous pore structure and a pore size of approximately 100 µm.The different scaffolds were incorporated into electronic devices such as transmembrane electrodes to characterize the electrical properties and evaluate the reproducibility of the scaffolds prior to cell culture. No significant change in the electrochemical impedance spectra was observed despite the large difference in porosity of the different scaffolds. In addition, the different scaffolds were used to host and monitor biological cells like fibroblasts and endothelial cells. Cell growth and proliferation in the different scaffolds was also monitored by immunofluorescence microscopy. It was observed that a pre-cooling protocol and a freezing rate of 0.5°C/min helps to fabricate scaffolds with an optimized, uniform and homogenous pore morphology. This design protocol is highly beneficial in reducing the random artifacts of the nucleation process and generating scaffolds highly conducive to cell growth and survival and to create a versatile bioelectronic platform for studying in-vitro cell models.A new, sophisticated bioelectronic device was constructed with the scaffolds with the operation mode of an electrode and an organic electrochemical transistor. The device operation models an electrochemical cell with two or three electrodes and is used to build different in vitro organ models. In this presentation, I show the use of electrochemical techniques to monitor biological phenomenon based on 3D conducting polymer scaffolds.

Advancing Electrochemical Energy Storage: The Synergistic Impact of Sulfur Nano-Confinement in Hierarchically Porous Jute-Derived Activated Carbon for Enhanced Supercapacitor Performance

The availability of energy is a cornerstone for the modernization, automation, and economic growth of nations. With the rapid depletion of fossil fuels and rising environmental concerns, such as CO2 emissions leading to global warming, there has been an intensified search for alternative, renewable energy sources like solar and wind power. However, their intermittent nature necessitates robust electric energy storage systems for effectively harnessing these resources. Electrochemical energy storage devices, particularly batteries and supercapacitors, have emerged as a focal point of recent research due to their potential to bridge this gap. While supercapacitors are known for their high power density and long cycle life, they typically exhibit limited energy density. Recent advancements have shown that composites combining carbonaceous materials with redox-active nanomaterials can significantly enhance supercapacitors' electrochemical performance. In this context, our research explores the development of hierarchically porous activated carbon nanosheets (JAC) derived from jute, an abundantly available biomass. Using a straightforward pyrolysis process, we have investigated its potential in supercapacitor applications. The prepared JAC, when employed as an electrode material in a symmetric supercapacitor with a glycerol-based bio-electrolyte, demonstrated higher specific capacitance compared to its commercial counterparts. Further innovation was achieved through the introduction of sulfur doping in JAC (S-doped JAC). This novel approach leverages the inherent porous nanosheet morphology of JAC and heteroatom modification to yield exceptional electrochemical performance. Our findings reveal that the S-doped JAC composite, particularly the variant with 25% sublimed sulfur (SJAC-25), significantly outperforms the standard JAC in terms of specific capacitance (230 F/g vs. 130 F/g at 1.0 A/g current density) in a glycerol-KOH bio-based electrolyte. Moreover, a symmetric supercapacitor assembled with SJAC-25 showcased an impressive energy density of 32 Wh/kg at a power density of 500 W/kg, maintaining 28 Wh/kg even at a heightened power density of 2500 W/kg. This demonstrates its capability to retain high energy efficiency under varying power conditions. Additionally, the SJAC-25 based supercapacitor exhibited remarkable durability, with about 94% capacitance retention and 86% Coulombic efficiency after 10,000 charge-discharge cycles. Our research not only highlights the potential of processed bio-waste as a viable material for energy storage but also introduces an advanced, scalable, and straightforward synthesis method. This method could pave the way for the preparation of highly porous and sulfur-doped nanoporous carbon, setting a new benchmark for high-performance electrochemical energy storage applications.

Assessing porosity limit in freeze‐cast sintered lithium titanate (Li4Ti5O12) materials

AbstractThis study aims to assess the lower limit of porosity that can be achieved in freeze‐cast sintered lithium titanate (LTO) materials while maintaining the characteristic pore directionality. LTO materials were fabricated with solid loading varying in the range of 30–37 vol.%. Sucrose and cationic dispersant were used to vary viscosity and total solute concentration in the aqueous LTO suspensions. Two series of suspension compositions were selected for freeze‐casting. In one series, aqueous suspensions were prepared by mixing deionized (DI) water, sucrose, and LTO powder, while in the other series, aqueous suspensions were prepared by mixing DI water, sucrose, cationic dispersant (1‐hexadecyl)trimethylammonium bromide (CTAB), and LTO powder. With increasing solid loading from 30 to 37 vol.%, porosity in the sintered materials decreased from about 50 to 36 vol.%. LTO materials fabricated from suspensions containing sucrose exhibited well‐developed characteristic freeze‐cast microstructure. Unexpectedly, LTO materials fabricated from suspensions containing sucrose and dispersant exhibited cellular pore morphology irrespective of the solid loading. Sample height had an impact on microstructure evolution in the transition zone and zone length. With the increasing solid loading from 30 to 37 vol.%, the compressive strength of sintered LTO materials having the characteristic freeze‐cast microstructure increased from about 110 to 240 MPa.