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Fulltext Mesoporous Carbon: A Versatile Material for Scientific Applications

Rahman MM, Ara MG, Alim MA, Uddin MS, Najda A, Albadrani GM, et al.

Int J Mol Sci, 2021 Apr 26;22(9).
PMID: 33925852 DOI: 10.3390/ijms22094498

Mesoporous carbon is a promising material having multiple applications. It can act as a catalytic support and can be used in energy storage devices. Moreover, mesoporous carbon controls body's oral drug delivery system and adsorb poisonous metal from water and various other molecules from an aqueous solution. The accuracy and improved activity of the carbon materials depend on some parameters. The recent breakthrough in the synthesis of mesoporous carbon, with high surface area, large pore-volume, and good thermostability, improves its activity manifold in performing functions. Considering the promising application of mesoporous carbon, it should be broadly illustrated in the literature. This review summarizes the potential application of mesoporous carbon in many scientific disciplines. Moreover, the outlook for further improvement of mesoporous carbon has been demonstrated in detail. Hopefully, it would act as a reference guidebook for researchers about the putative application of mesoporous carbon in multidimensional fields.

Matched MeSH terms: Porosity
Fulltext The removal of anionic and cationic dyes from an aqueous solution using biomass-based activated carbon

Nizam NUM, Hanafiah MM, Mahmoudi E, Halim AA, Mohammad AW

Sci Rep, 2021 Apr 21;11(1):8623.
PMID: 33883637 DOI: 10.1038/s41598-021-88084-z

In this study, two biomass-based adsorbents were used as new precursors for optimizing synthesis conditions of a cost-effective powdered activated carbon (PAC). The PAC removed dyes from an aqueous solution using carbonization and activation by KOH, NaOH, and H2SO4. The optimum synthesis, activation temperature, time and impregnation ratio, removal rate, and uptake capacity were determined. The optimum PAC was analyzed and characterized using Fourier-transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), a field emission scanning electron microscope (FESEM), Zeta potential, and Raman spectroscopy. Morphological studies showed single-layered planes with highly porous surfaces, especially PAC activated by NaOH and H2SO4. The results showed that the experimental data were well-fitted with a pseudo-second-order model. Based on Langmuir isotherm, the maximum adsorption capacity for removing methylene blue (MB) was 769.23 mg g-1 and 458.43 mg g-1 for congo red (CR). Based on the isotherm models, more than one mechanism was involved in the adsorption process, monolayer for the anionic dye and multilayer for the cationic dye. Elovich and intraparticle diffusion kinetic models showed that rubber seed shells (RSS) has higher α values with a greater tendency to adsorb dyes compared to rubber seed (RS). A thermodynamic study showed that both dyes' adsorption process was spontaneous and exothermic due to the negative values of the enthalpy (ΔH) and Gibbs free energy (ΔG). The change in removal efficiency of adsorbent for regeneration study was observed in the seventh cycles, with a 3% decline in the CR and 2% decline in MB removal performance. This study showed that the presence of functional groups and active sites on the produced adsorbent (hydroxyl, alkoxy, carboxyl, and π - π) contributed to its considerable affinity for adsorption in dye removal. Therefore, the optimum PAC can serve as efficient and cost-effective adsorbents to remove dyes from industrial wastewater.

Matched MeSH terms: Porosity
Fulltext Formation and Evaluation of Silicon Substrate with Highly-Doped Porous Si Layers Formed by Metal-Assisted Chemical Etching

Li Y, Van Toan N, Wang Z, Samat KFB, Ono T

Nanoscale Res Lett, 2021 Apr 20;16(1):64.
PMID: 33877472 DOI: 10.1186/s11671-021-03524-z

Porous silicon (Si) is a low thermal conductivity material, which has high potential for thermoelectric devices. However, low output performance of porous Si hinders the development of thermoelectric performance due to low electrical conductivity. The large contact resistance from nonlinear contact between porous Si and metal is one reason for the reduction of electrical conductivity. In this paper, p- and n-type porous Si were formed on Si substrate by metal-assisted chemical etching. To decrease contact resistance, p- and n-type spin on dopants are employed to dope an impurity element into p- and n-type porous Si surface, respectively. Compared to the Si substrate with undoped porous samples, ohmic contact can be obtained, and the electrical conductivity of doped p- and n-type porous Si can be improved to 1160 and 1390 S/m, respectively. Compared with the Si substrate, the special contact resistances for the doped p- and n-type porous Si layer decreases to 1.35 and 1.16 mΩ/cm2, respectively, by increasing the carrier concentration. However, the increase of the carrier concentration induces the decline of the Seebeck coefficient for p- and n-type Si substrates with doped porous Si samples to 491 and 480 μV/K, respectively. Power factor is related to the Seebeck coefficient and electrical conductivity of thermoelectric material, which is one vital factor that evaluates its output performance. Therefore, even though the Seebeck coefficient values of Si substrates with doped porous Si samples decrease, the doped porous Si layer can improve the power factor compared to undoped samples due to the enhancement of electrical conductivity, which facilitates its development for thermoelectric application.

Matched MeSH terms: Porosity
Fulltext Improved Bacteriostatic and Anticorrosion Effects of Polycaprolactone/Chitosan Coated Magnesium via Incorporation of Zinc Oxide

Bakhsheshi-Rad HR, Hamzah E, Ying WS, Razzaghi M, Sharif S, Ismail AF, et al.

Materials (Basel), 2021 Apr 12;14(8).
PMID: 33921460 DOI: 10.3390/ma14081930

Magnesium has been recognized as a groundbreaking biodegradable biomaterial for implant applications, but its use is limited because it degrades too quickly in physiological solutions. This paper describes the research on the influence of polycaprolactone (PCL)/chitosan (CS)/zinc oxide (ZnO) composite coating (PCL/CS/ZnO) on the corrosion resistance and antibacterial activity of magnesium. The PCL/CS film presented a porous structure with thickness of about 40-50 μm, while after incorporation of ZnO into the PCL/CS, a homogenous film without pores and defects was attained. The ZnO embedded in PCL/CS enhanced corrosion resistance by preventing corrosive ions diffusion in the magnesium substrate. The corrosion, antibacterial, and cell interaction mechanism of the PCL/CS/ZnO composite coating is discussed in this study. In vitro cell culture revealed that the PCL/CS coating with low loaded ZnO significantly improved cytocompatibility, but coatings with high loaded ZnO were able to induce some cytotoxicity osteoblastic cells. It was also found that enhanced antibacterial activity of the PCL/CS/ZnO coating against both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria, while less significant antibacterial activity was detected for uncoated Mg and PCL/CS coating. Based on the results, the PCL/CS coatings loaded with low ZnO content may be recommended as a candidate material for biodegradable Mg-based orthopedic implant applications.

Matched MeSH terms: Porosity
Fulltext On solution existence of MHD Casson nanofluid transportation across an extending cylinder through porous media and evaluation of priori bounds

Abdal S, Hussain S, Siddique I, Ahmadian A, Ferrara M

Sci Rep, 2021 Apr 08;11(1):7799.
PMID: 33833251 DOI: 10.1038/s41598-021-86953-1

It is a theoretical exportation for mass transpiration and thermal transportation of Casson nanofluid over an extending cylindrical surface. The Stagnation point flow through porous matrix is influenced by magnetic field of uniform strength. Appropriate similarity functions are availed to yield the transmuted system of leading differential equations. Existence for the solution of momentum equation is proved for various values of Casson parameter [Formula: see text], magnetic parameter M, porosity parameter [Formula: see text] and Reynolds number Re in two situations of mass transpiration (suction/injuction). The core interest for this study aroused to address some analytical aspects. Therefore, existence of solution is proved and uniqueness of this results is discussed with evaluation of bounds for existence of solution. Results for skin friction factor are established to attain accuracy for large injection values. Thermal and concentration profiles are delineated numerically by applying Runge-Kutta method and shooting technique. The flow speed retards against M, [Formula: see text] and [Formula: see text] for both situations of mass injection and suction. The thermal boundary layer improves with Brownian and thermopherotic diffusions.

Matched MeSH terms: Porosity
Arabinoxylan/graphene-oxide/nHAp-NPs/PVA bionano composite scaffolds for fractured bone healing

Aslam Khan MU, Haider A, Abd Razak SI, Abdul Kadir MR, Haider S, Shah SA, et al.

J Tissue Eng Regen Med, 2021 04;15(4):322-335.
PMID: 33432773 DOI: 10.1002/term.3168

The importance of bone scaffolds has increased many folds in the last few years; however, during bone implantation, bacterial infections compromise the implantation and tissue regeneration. This work is focused on this issue while not compromising on the properties of a scaffold for bone regeneration. Biocomposite scaffolds (BS) were fabricated via the freeze-drying technique. The samples were characterized for structural changes, surface morphology, porosity, and mechanical properties through spectroscopic (Fourier transform-infrared [FT-IR]), microscopic (scanning electron microscope [SEM]), X-ray (powder X-ray diffraction and energy-dispersive X-ray), and other analytical (Brunauer-Emmett-Teller, universal testing machine Instron) techniques. Antibacterial, cellular, and hemocompatibility assays were performed using standard protocols. FT-IR confirmed the interactions of all the components. SEM illustrated porous and interconnected porous morphology. The percentage porosity was in the range of 49.75%-67.28%, and the pore size was 215.65-470.87 µm. The pore size was perfect for cellular penetration. Thus, cells showed significant proliferation onto these scaffolds. X-ray studies confirmed the presence of nanohydroxyapatite and graphene oxide (GO). The cell viability was 85%-98% (BS1-BS3), which shows no significant toxicity of the biocomposite. Furthermore, the biocomposites exhibited better antibacterial activity, no effect on the blood clotting (normal in vitro blood clotting), and less than 5% hemolysis. The ultimate compression strength for the biocomposites increased from 4.05 to 7.94 with an increase in the GO content. These exciting results revealed that this material has the potential for possible application in bone tissue engineering.

Matched MeSH terms: Porosity
Fulltext Pharmaco-Technical Evaluation of Statistically Formulated and Optimized Dual Drug-Loaded Silica Nanoparticles for Improved Antifungal Efficacy and Wound Healing

Masood A, Maheen S, Khan HU, Shafqat SS, Irshad M, Aslam I, et al.

ACS Omega, 2021 Mar 30;6(12):8210-8225.
PMID: 33817480 DOI: 10.1021/acsomega.0c06242

The current research aimed at designing mesoporous silica nanoparticles (MSNs) for a controlled coadministration of salicylic acid (SA) and ketoconazole (KCZ) to effectively treat highly resistant fungal infections. The sol-gel method was used to formulate MSNs, which were further optimized using central composite rotatable design (CCRD) by investigating mathematical impact of independent formulation variables such as pH, stirring time, and stirring speed on dependent variables entrapment efficiency (EE) and drug release. The selected optimized MSNs and pure drugs were subjected to comparative in vitro/in vivo antifungal studies, skin irritation, cytotoxicity, and histopathological evaluations. The obtained negatively charged (-23.1), free flowing spherical, highly porous structured MSNs having a size distribution of 300-500 nm were suggestive of high storage stability and improved cell proliferation due to enhanced oxygen supply to cells. The physico-chemical evaluation of SA/KCZ-loaded MSNs performed through powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and thermal gravimetric analysis (TGA) indicates absolute lack of any interaction between formulation components and successful encapsulation of both drugs in MSNs. The EESA, EEKCZ, SA release, and KCZ release varied significantly from 34 to 89%, 36 to 85%, 39 to 88%, and 43 to 90%, respectively, indicating the quadratic impact of formulation variables on obtained MSNs. For MSNs, the skin tolerability and cell viability percentage rate were also having an extraordinary advantage over suspension of pure drugs. The optimized SA/KCZ-loaded MSNs demonstrated comparatively enhanced in vitro/in vivo antifungal activities and rapid wound healing efficacy in histopathological evaluation without any skin irritation impact, suggesting the MSNs potential for the simultaneous codelivery of antifungal and keratolyic agents in sustained release fashion.

Matched MeSH terms: Porosity
Fulltext Image Analysis of Surface Porosity Mortar Containing Processed Spent Bleaching Earth

Wei Chong B, Othman R, Jaya RP, Shu Ing D, Li X, Wan Ibrahim MH, et al.

Materials (Basel), 2021 Mar 28;14(7).
PMID: 33800634 DOI: 10.3390/ma14071658

Image analysis techniques are gaining popularity in the studies of civil engineering materials. However, the current established image analysis methods often require advanced machinery and strict image acquisition procedures which may be challenging in actual construction practices. In this study, we develop a simplified image analysis technique that uses images with only a digital camera and does not have a strict image acquisition regime. Mortar with 10%, 20%, 30%, and 40% pozzolanic material as cement replacement are prepared for the study. The properties of mortar are evaluated with flow table test, compressive strength test, water absorption test, and surface porosity based on the proposed image analysis technique. The experimental results show that mortar specimens with 20% processed spent bleaching earth (PSBE) achieve the highest 28-day compressive strength and lowest water absorption. The quantified image analysis results show accurate representation of mortar quality with 20% PSBE mortar having the lowest porosity. The regression analysis found strong correlations between all experimental data and the compressive strength. Hence, the developed technique is verified to be feasible as supplementary mortar properties for the study of mortar with pozzolanic material.

Matched MeSH terms: Porosity
Encapsulation of caffeine into starch matrices: Bitterness evaluation and suppression mechanism

Shao M, Li S, Tan CP, Kraithong S, Gao Q, Fu X, et al.

Int J Biol Macromol, 2021 Mar 15;173:118-127.
PMID: 33444656 DOI: 10.1016/j.ijbiomac.2021.01.043

In this study, caffeine (CA) was encapsulated into food-grade starch matrices, including swelled starch (SS), porous starch (PS), and V-type starch (VS). The bitterness of the microcapsules and suppression mechanisms were investigated using an electronic tongue, molecular dynamics (MD) simulation and the in vitro release kinetics of CA. All the CA-loaded microcapsules showed a lower bitterness intensity than the control. The MD results proved that the weak interactions between starch and CA resulted in a moderate CA release rate for SS-CA microcapsules. The PS-CA microcapsule presented the longest CA release, up to 40 min, whereas the VS-CA microcapsule completely released CA in 9 min. The CA release rate was found to be related to the microcapsule structure and rehydration properties. A low CA bitterness intensity could be attributed to a delay in the CA release rate and resistance to erosion of the microcapsules. The results of this work are valuable for improving starch-based microcapsules (oral-targeted drug-delivery systems) by suppressing the bitterness of alkaloid compounds.

Matched MeSH terms: Porosity
Fulltext Thermal Charging Optimization of a Wavy-Shaped Nano-Enhanced Thermal Storage Unit

Ghalambaz M, Mehryan SAM, Hajjar A, Shdaifat MYA, Younis O, Talebizadehsardari P, et al.

Molecules, 2021 Mar 09;26(5).
PMID: 33803488 DOI: 10.3390/molecules26051496

A wavy shape was used to enhance the thermal heat transfer in a shell-tube latent heat thermal energy storage (LHTES) unit. The thermal storage unit was filled with CuO-coconut oil nano-enhanced phase change material (NePCM). The enthalpy-porosity approach was employed to model the phase change heat transfer in the presence of natural convection effects in the molten NePCM. The finite element method was applied to integrate the governing equations for fluid motion and phase change heat transfer. The impact of wave amplitude and wave number of the heated tube, as well as the volume concertation of nanoparticles on the full-charging time of the LHTES unit, was addressed. The Taguchi optimization method was used to find an optimum design of the LHTES unit. The results showed that an increase in the volume fraction of nanoparticles reduces the charging time. Moreover, the waviness of the tube resists the natural convection flow circulation in the phase change domain and could increase the charging time.

Matched MeSH terms: Porosity
Mitigation of indoor air pollution: A review of recent advances in adsorption materials and catalytic oxidation

Yue X, Ma NL, Sonne C, Guan R, Lam SS, Van Le Q, et al.

J Hazard Mater, 2021 03 05;405:124138.
PMID: 33092884 DOI: 10.1016/j.jhazmat.2020.124138

Indoor air pollution with toxic volatile organic compounds (VOCs) and fine particulate matter (PM2.5) is a threat to human health, causing cancer, leukemia, fetal malformation, and abortion. Therefore, the development of technologies to mitigate indoor air pollution is important to avoid adverse effects. Adsorption and photocatalytic oxidation are the current approaches for the removal of VOCs and PM2.5 with high efficiency. In this review we focus on the recent development of indoor air pollution mitigation materials based on adsorption and photocatalytic decomposition. First, we review on the primary indoor air pollutants including formaldehyde, benzene compounds, PM2.5, flame retardants, and plasticizer: Next, the recent advances in the use of adsorption materials including traditional biochar and MOF (metal-organic frameworks) as the new emerging porous materials for VOCs absorption is reviewed. We review the mechanism for mitigation of VOCs using biochar (noncarbonized organic matter partition and adsorption) and MOF together with parameters that affect indoor air pollution removal efficiency based on current mitigation approaches including the mitigation of VOCs using photocatalytic oxidation. Finally, we bring forward perspectives and directions for the development of indoor air mitigation technologies.

Matched MeSH terms: Porosity
Novel Self-Directing Single-Polymer Jet Developing Layered-Like 3D Buckled Microfibrous Scaffolds for Tissue Engineering Applications

Navaneethan B, Vijayakumar GP, Ashang Luwang L, Karuppiah S, Jayarama Reddy V, Ramakrishna S, et al.

ACS Appl Mater Interfaces, 2021 Mar 03;13(8):9691-9701.
PMID: 33605136 DOI: 10.1021/acsami.0c22028

Electrospinning is a promising technique for the fabrication of bioscaffolds in tissue engineering applications. Pertaining issues of multiple polymer jets and bending instabilities result in random paths which lend poor controllability over scaffolds morphology for affecting the porosity and mechanical stability. The present study alleviates these challenges by demonstrating a novel self-directing single jet taking a specifically patterned path to deposit fibers into circular and uniform scaffolds without tuning any externally controlled parameters. High-speed camera observation revealed that the charge retention and dissipation on the collected fibers caused rapid autojet switching between the two jetting modes, namely, a microcantilever-like armed jet motion and a whipping motion, which sequentially expand the area and thickness of the scaffolds, respectively, in a layered-like fashion. The physical properties showed that the self-switching dual-jet modes generated multilayered microfibrous scaffolds (MFSs) with dual morphologies and varied fiber packing density, thereby establishing the gradient porosity and mechanical strength (through buckled fibers) in the scaffolds. In vitro studies showed that as-spun scaffolds are cell-permeable hierarchical 3D microporous structures enabling lateral cell seeding into multiple layers. The cell proliferation on days 6 and 9 increased 21% and 38% correspondingly on MFSs than on nanofibrous scaffolds (NFSs) done by conventional multijets electrospinning. Remarkably, this novel and single-step process is highly reproducible and tunable for developing fibrous scaffolds for tissue engineering applications.

Matched MeSH terms: Porosity
Assessing the impact of water infiltration on LNAPL mobilization in sand column using simplified image analysis method

Alazaiza MYD, Ramli MH, Copty NK, Ling MC

J Contam Hydrol, 2021 Mar;238:103769.
PMID: 33465656 DOI: 10.1016/j.jconhyd.2021.103769

Laboratory-scale column experiments were carried out to assess the influence of water infiltration on pooled light non-aqueous phase liquid (LNAPL) redistribution in porous media. A simplified image analysis method (SIAM) was used to evaluate the saturation distributions of the LNAPL and water in the entire domain under dynamic conditions. The experiments were conducted for high/low LNAPL volumes LNAPL volumes differentiated as low and high volumes. High resolution SIAM images of the soil column during LNAPL migration and water infiltration events were captured and analyzed. Results indicated that the capillary fringe is about 6-7 cm which was consistent with the capillary height derived from empirical equations. Moreover, SIAM provided an estimate of the field capacity (30%) of the sand. Once the LNAPL infiltration stage was started, the LNAPL was observed to rapidly migrate through the vadose zone. For the case of large LNAPL volume, the LNAPL penetrated further into capillary fringe zone. Analysis of SIAM images showed that the LNAPL redistribution was observed to vary significantly with the rate of infiltration. For higher water infiltration intensity, the injected water exerted a larger hydrodynamic force on the entrapped LNAPL forcing it move further downward into the capillary zone and the saturated zone. Overall, this study demonstrated that the SIAM technique is an accurate and cost-effective tool for the visualization of the time-dependent NAPL/water movement in laboratory-scale experiments and dynamic changes in fluid saturation in porous media.

Matched MeSH terms: Porosity
Fulltext Assessment of Extra-Cortical Bone Bridge Interface in Cemented Mega Endoprosthesis for Limb Salvage Surgery

Murugan K, Faisham WI, Zulmi W

Malays Orthop J, 2021 Mar;15(1):93-99.
PMID: 33880154 DOI: 10.5704/MOJ.2103.014

Introduction: Mega endoprosthesis replacement for resection of primary malignant bone tumour requires immediate and long-term stability, particularly in the young and active patient. Extracortical bone bridge interface (EBBI) is a technique whereby autograft is wrapped around the interface junction of bone and porous-coated implant to induce and enhance bone formation for biological incorporation. This procedure increases the mean torsional stiffness and the mean maximum torque, which eventually improves the implant's long-term survival.
Material and methods: The extracortical bone bridge interface's radiological parameter was evaluated at the prosthesis bone junction two years after surgery utilising a picture archiving and communication system (PACS). The radiograph's anteroposterior and lateral view was analysed for both thickness and length in all four cortices. The analysis was done in SPSS Version 24 using One-Way ANOVA and independent T-Test. Results were presented as mean and standard deviation and considered significant when the p-value was < 0.05.
Results: The mean average thickness was 2.2293mm (SD 1.829), and the mean average length was 31.95% (SD 24.55). We observed that the thickness and length of EBBI were superior in the young patient or patients with giant cell tumour that did not receive chemotherapy, compared to patients treated for osteosarcoma. The distal femur also had better EBBI compared to the proximal tibia. However, the final multivariable statistical analysis showed no significant difference in all variables. EBBI thickness was significantly and positively correlated with EBBI Length (p<0.001). We conclude that, for each 1mm increase in EBBI thickness, the length will increase by 0.06% on average. About 17.2% of patients out of the 29 showed no radiological evidence of EBBI.
Conclusion: From our study, there were no factors that significantly contributed to the formation and incorporation of EBBI.

Matched MeSH terms: Porosity
Fulltext Role of Sintering Temperature in Production of Nepheline Ceramics-Based Geopolymer with Addition of Ultra-High Molecular Weight Polyethylene

Ahmad R, Abdullah MMAB, Ibrahim WMW, Hussin K, Ahmad Zaidi FH, Chaiprapa J, et al.

Materials (Basel), 2021 Feb 25;14(5).
PMID: 33669116 DOI: 10.3390/ma14051077

The primary motivation of developing ceramic materials using geopolymer method is to minimize the reliance on high sintering temperatures. The ultra-high molecular weight polyethylene (UHMWPE) was added as binder and reinforces the nepheline ceramics based geopolymer. The samples were sintered at 900 °C, 1000 °C, 1100 °C, and 1200 °C to elucidate the influence of sintering on the physical and microstructural properties. The results indicated that a maximum flexural strength of 92 MPa is attainable once the samples are used to be sintered at 1200 °C. It was also determined that the density, porosity, volumetric shrinkage, and water absorption of the samples also affected by the sintering due to the change of microstructure and crystallinity. The IR spectra reveal that the band at around 1400 cm-1 becomes weak, indicating that sodium carbonate decomposed and began to react with the silica and alumina released from gels to form nepheline phases. The sintering process influence in the development of the final microstructure thus improving the properties of the ceramic materials.

Matched MeSH terms: Porosity
Fulltext Surface Modification of Polytetrafluoroethylene Hollow Fiber Membrane for Direct Contact Membrane Distillation through Low-Density Polyethylene Solution Coating

Mohd Ramli MR, Ahmad AL, Leo CP

ACS Omega, 2021 Feb 23;6(7):4609-4618.
PMID: 33644568 DOI: 10.1021/acsomega.0c05107

Membrane distillation (MD) is an attractive technology for the separation of highly saline water used with a polytetrafluoroethylene (PTFE) hollow fiber (HF) membrane. A hydrophobic coating of low-density polyethylene (LDPE) coats the outer surface of the PTFE membrane to resolve membrane wetting as well as increase membrane permeability flux and salt rejection, a critical problem regarding the MD process. LDPE concentrations in coating solution have been studied and optimized. Consequently, the LDPE layer altered membrane morphology by forming a fine nanostructure on the membrane surface that created a hydrophobic layer, a high roughness of membrane, and a uniform LDPE network. The membrane coated with different concentrations of LDPE exhibited high water contact angles of 135.14 ± 0.24 and 138.08 ± 0.01° for membranes M-3 and M-4, respectively, compared to the pristine membrane. In addition, the liquid entry pressure values of LDPE-incorporated PTFE HF membranes (M-1 to M-5) were higher than that of the uncoated membrane (M-0) with a small decrease in the percentage of porosity. The M-3 and M-4 membranes demonstrated higher flux values of 4.12 and 3.3 L m-2 h-1 at 70 °C, respectively. On the other hand, the water permeation flux of 1.95 L m-2 h-1 for M-5 further decreased when LDPE concentration is increased.

Matched MeSH terms: Porosity
Fulltext The Role of Zinc Chloride in Enhancing Mechanical, Thermal and Electrical Performance of Ethylene Vinyl Acetate/Carbonized Wood Fiber Conductive Composite

Mohd Pisal MH, Osman AF, Jin TS, Rahman RA, Alrashdi AA, Masa A

Polymers (Basel), 2021 Feb 17;13(4).
PMID: 33671304 DOI: 10.3390/polym13040600

Carbonized natural filler can offer the production of low cost composites with an eco-friendliness value. The evolving field of electronics encourages the exploration of more functions and potential for carbonized natural filler, such as by modifying its surface chemistry. In this work, we have performed surface modification on carbonized wood fiber (CWF) prior to it being used as filler in the ethylene vinyl acetate (EVA) composite system. Zinc chloride (ZnCl2) with various contents (2 to 8 wt%) was used to surface modify the CWF and the effects of ZnCl2 composition on the surface morphology and chemistry of the CWF filler were investigated. Furthermore, the absorptive, mechanical, thermal, and electrical properties of the EVA composites containing CWF-ZnCl2 were also analyzed. SEM images indicated changes in the morphology of the CWF while FTIR analysis proved the presence of ZnCl2 functional groups in the CWF. EVA composites incorporating the CWF-ZnCl2 showed superior mechanical, thermal and electrical properties compared to the ones containing the CWF. The optimum content of ZnCl2 was found to be 6 wt%. Surface modification raised the electrical conductivity of the EVA/CWF composite through the development of conductive deposits in the porous structure of the CWF as a channel for ionic and electronic transfer between the CWF and EVA matrix.

Matched MeSH terms: Porosity
Fulltext Electromagnetic Characterization of a Multiwalled Carbon Nanotubes-Silver Nanoparticles-Reinforced Polyvinyl Alcohol Hybrid Nanocomposite in X-Band Frequency

Yusof Y, Moosavi S, Johan MR, Badruddin IA, Wahab YA, Hamizi NA, et al.

ACS Omega, 2021 Feb 16;6(6):4184-4191.
PMID: 33644542 DOI: 10.1021/acsomega.0c04864

This study presents the electromagnetic (EM) characterization of a multiwalled carbon nanotubes (MWCNT)-silver nanoparticles (AgNP)-reinforced poly(vinyl alcohol) (PVA) hybrid nanocomposite fabricated via the solution mixing technique. Primarily, the structure and morphological properties of the PVA/MWCNT-AgNP hybrid nanocomposite are confirmed by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The complex permittivity (ε*) and permeability (μ*), as well as the electromagnetic scattering parameters are measured using a PNA network analyzer equipped with X-band waveguide. The results showed an enhanced permittivity (ε' ≈ 25) value of the hybrid nanocomposite in the frequency range of 8-12 GHz. However, the permeability decreased to almost zero (μ' ≈ 0.4) since the inclusion of AgNP with an average particle size of 40 nm is not susceptible to magnetization and causes higher magnetic losses (tan δμ) than dielectric losses (tan δε). Remarkably, the hybrid nanocomposite reduced transmission of electromagnetic (EM) wave by nearly 60% in comparison to PVA/MWCNT. This is attributed to the enhanced absorption and reflection at the nanotubes, and metal-dielectric interfaces have induced multiple internal reflections owing to the porous structure of the nanocomposite. The prospect of the PVA/MWCNT-AgNP hybrid nanocomposite is favorable as a thin absorbing material for EM shielding applications.

Matched MeSH terms: Porosity
Fulltext Hybrid Collagen Hydrogel/Chondroitin-4-Sulphate Fortified with Dermal Fibroblast Conditioned Medium for Skin Therapeutic Application

Maarof M, Mohd Nadzir M, Sin Mun L, Fauzi MB, Chowdhury SR, Idrus RBH, et al.

Polymers (Basel), 2021 Feb 08;13(4).
PMID: 33567703 DOI: 10.3390/polym13040508

The current strategy for rapid wound healing treatment involves combining a biomaterial and cell-secreted proteins or biomolecules. This study was aimed at characterizing 3-dimensional (3D) collagen hydrogels fortified with dermal fibroblast-conditioned medium (DFCM) as a readily available acellular skin substitute. Confluent fibroblasts were cultured with serum-free keratinocyte-specific medium (KM1 and KM2) and fibroblast-specific medium (FM) to obtain DFCM. Subsequently, the DFCM was mixed with collagen (Col) hydrogel and chondroitin-4-sulphate (C4S) to fabricate 3D constructs termed Col/C4S/DFCM-KM1, Col/C4S/DFCM-KM2, and Col/C4S/DFCM-FM. The constructs successfully formed soft, semi-solid and translucent hydrogels within 1 h of incubation at 37 °C with strength of <2.5 Newton (N). The Col/C4S/DFCM demonstrated significantly lower turbidity compared to the control groups. The Col/C4S/DFCM also showed a lower percentage of porosity (KM1: 35.15 ± 9.76%; KM2: 6.85 ± 1.60%; FM: 14.14 ± 7.65%) compared to the Col (105.14 ± 11.87%) and Col/C4S (143.44 ± 27.72%) constructs. There were no changes in both swelling and degradation among all constructs. Fourier transform infrared spectrometry showed that all groups consisted of oxygen-hydrogen bonds (O-H) and amide I, II, and III. In conclusion, the Col/C4S/DFCM constructs maintain the characteristics of native collagen and can synergistically deliver essential biomolecules for future use in skin therapeutic applications.

Matched MeSH terms: Porosity
Fulltext Novel PVDF-PVP Hollow Fiber Membrane Augmented with TiO2 Nanoparticles: Preparation, Characterization and Application for Copper Removal from Leachate

Abba MU, Man HC, Azis RS, Isma Idris A, Hazwan Hamzah M, Yunos KF, et al.

Nanomaterials (Basel), 2021 Feb 04;11(2).
PMID: 33557323 DOI: 10.3390/nano11020399

High proportion of copper has become a global challenge owing to its negative impact on the environment and public health complications. The present study focuses on the fabrication of a polyvinylidene fluoride (PVDF)-polyvinyl pyrrolidone (PVP) fiber membrane incorporated with varying loading (0, 0.5, 1.0, 1.5, and 2.0 wt%) of titanium dioxide (TiO2) nanoparticles via phase inversion technique to achieve hydrophilicity along with high selectivity for copper removal. The developed fibers were characterized based on scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), permeability, porosity, zeta potential, and contact angle. The improved membrane (with 1.0 wt% TiO2) concentration recorded the maximum flux (223 L/m2·h) and copper rejection (98.18%). Similarly, 1.0 wt% concentration of TiO2 nanoparticles made the membrane matrix more hydrophilic with the least contact angle of 50.01°. The maximum copper adsorption capacity of 69.68 mg/g was attained at 1.0 wt% TiO2 concentration. The experimental data of adsorption capacity were best fitted to the Freundlich isotherm model with R2 value of 0.99573. The hybrid membrane developed in this study has considerably eliminated copper from leachate and the concentration of copper in the permeate was substantially reduced to 0.044 mg/L, which is below standard discharge threshold.

Matched MeSH terms: Porosity

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