Chemical Surface Functionalization Research Articles

Synthesis Processes, Photoluminescence Mechanism, and the Toxicity of Amorphous or Polymeric Carbon Dots.

Fluorescence is the emission of light following photon absorption. This optical phenomenon has many applications in daily life, such as in LED lamps, forensics, and bioimaging. Traditionally, small-molecule fluorophores were most common, but the types of molecules and particles with compelling fluorescence properties have expanded. For example, green fluorescent protein (GFP) was isolated from jellyfish and won the Nobel prize in 2008 due to its significant utility as a fluorescent biomarker. Using the intrinsic fluorescence of GFP, many previously invisible biological processes and substances can now be observed and studied. Other fluorescent materials have also been developed, greatly expanding the potential applications. Semiconductor quantum dots (QDs), which have bright fluorescence and a narrow bandwidth, are a popular choice for display technologies. However, QDs are made of heavy metal elements such as Cd and Se, which pose potential safety concerns to the environment and human health. Thus, new fluorescent organic materials are being developed to mitigate the toxicological concerns while maintaining the QD advantages.One type of new material attracting great attention as an environmentally friendly substitute for semiconductor QDs is carbon dots (CDs). CDs have been developed with strong fluorescence, good photostability, and low toxicity using a variety of precursors, and some synthesis processes have good potential for scale-up. However, since they are made of a variety of materials and through different methods, the structure and properties of CDs can differ from preparation to preparation. There are three major types of CDs: graphene quantum dots (GQDs), carbon quantum dots (CQDs), and amorphous or polymeric carbon dots (PCDs). This Account focuses on PCDs and their unique properties by comparing it with other types of CDs. The synthesis processes, fluorescence properties, fluorescence mechanisms, and toxicity are discussed below with an emphasis on the distinct attributes of PCDs.PCDs can be synthesized from small molecules or polymers. They have an amorphous or cross-linked polymer structure with bright fluorescence. This fluorescence is possibly due to cross-link-enhanced emission or clusteroluminescence that arises from the through-space interactions of heteroatomic-rich functional groups. Other fluorescence mechanisms of CDs, including distinct contributions from the carbon core and surface states, may also contribute. The toxicological profiles of CDs are influenced by the chemical composition, surface functionalization, and light illumination. CDs are generally thought to be of low toxicity, and this can be further improved by removing toxic byproducts, functionalizing the surface, and reducing light exposure to minimize the generation of reactive oxygen species.

Challenges and innovative strategies related to synthesis and electrocatalytic/energy storage applications of metal sulfides and its derivatives

Energy is one the most fundamental necessities in daily life which is fulfilled from non-renewable and non-ecofriendly resources that are not only expensive in terms of costs but also depleting with time and causingenvironmental pollution. The quest for the renewable, eco-friendly and economic energy resources is in progression tomitigate the energy demands. In this context, cogent energy alternatives are under investigations to develop innovative strategies based on renewable, affordable and widely available resources. In these perspectives, Metal Sulfides (MS) and their derivatives are sensible, operative and eco-friendly electrocatalysts with ultramodern physiognomies because of extensive durability, porous topography, high surface area, extensive varieties, cost effectiveness, simplicity and chemical functionality. Various synthetic strategies such as hydrothermal, solvothermal and other miscellaneous techniques have been followed to design metal sulfides and their derivatives of countless compositions. The synthesized metal sulfides and their derivatives are favored for electrocatalytic solicitations with characteristic synergetic and plasmonic effects in order to explorehydrogen evolutionreaction (HER), oxygen evolution reaction (OER), overall water splitting (OWS), carbon dioxide reduction ( CO 2 RR ), and super capacitance. Appraising these synthetic strategies and electrocatalytic features, metal sulfides could be influential to attempt new, renewable and eco-friendly energy resources.

Significance of m6A regulation in environmental health and safety (EHS) assessment: MWCNTs induced pulmonary toxicity through m6A modifications of mitophagy-related genes

Multi-walled carbon nanotubes (MWCNTs) have been widely used in consumer and industrial products owing to their outstanding physicochemical characteristics. However, they have potential adverse effects on human organs, especially the lungs. Although many studies have focused on the molecular mechanisms responsible for MWCNTs-induced macrophage activation and immunotoxicity, the potential toxic effect of MWCNTs on lung cells was largely overlooked. In this study, it was found that compared with pristine (P-MWCNTs) and aminated MWCNTs (MWCNTs-NH2), carboxylated MWCNTs (MWCNTs-COOH) (at a dosage that failed to induce obvious cytotoxicity) can promote mitophagy occurrence and cell cycle arrest. Intriguingly, the mechanism is ascribed to an epigenetic regulation through which MWCNTs-COOH promotes the m6A modification of mitophagy-related genes by enhancing m6A methyltransferase METTL3/14 nuclear translocation, thereby leading to mitophagy-dependent cell cycle arrest in an m6A methylation-dependent manner. In addition, MWCNTs-COOH interacts with and disrupts the oligomeric structure of membrane protein caveolin-1 to activate Wnt/β-catenin pathway and then trigger m6A modification-dependent cytotoxicity. The results of this study unraveled an important role and the underlying mechanism of the surface chemical functionalization in regulating MWCNTs-induced pulmonary toxicity. This study highlights the significance of m6A regulation in assessing the environmental health and safety (EHS) impacts of MWCNTs, which can be generalized to a wide spectrum of nanomaterials.

The surface chemical functionality and diffusion mediated adsorption of organophosphates from their low concentration

The detection and removal of pesticides from their very low concentration solution are daunting tasks. The development of substrates leading to the adsorption of the pesticides requires a thorough understanding of the adsorption process. Here, we studied the interaction of two organophosphates, phorate, and malathion, on functionalized by using four different silane coupling agents, namely n-propyltrimethoxy silane (PTMS), octyltrimethoxy silane (OTMS), 3- (trimethoxysilyl) propyl methacrylate (TMSPMA) and 3- (triethoxysilyl) propionitrile (TESPN).Diffusion controlled kinetic model with a surface phase concept is developed. The concentration of the pesticides used in this work in the range of 1–20 mg/L. The model is fitted to the real-time adsorption data of phorate, and malathion over various substrates obtained using QCM-D. The results show that TMSPMA functionalized surface being more hydrophilic among all surfaces adsorbs hydrophobic pesticides molecules more uniformly. The monolayer adsorbed mass of pesticides obtained experimentally aligns with the theoretically calculated mass for TMSPMA functionalized silica surface. The adsorption is explained through molecular interactions. A reasonably strong binding with a possibility of reversible binding of phorate and malathion on TMSPMA functionalized surface is observed.

Interfacial interactions and reinforcing mechanisms of cellulose and chitin nanomaterials and starch derivatives for cement and concrete strength and durability enhancement: A review

AbstractNanomaterials have been widely researched for use in construction materials. Numerous studies demonstrate that nanomaterials in small quantities can significantly improve the macroscopic properties of cement paste, mortar, or concrete through various mechanisms. Nanomaterials retrieved from biomass sources have recently gained particular research interest due to remarkable structural properties and the source material’s abundance and renewability. Cellulose and chitin are the most abundant polysaccharides in nature; thus, they are candidates for nanomaterials extraction as multifunctional additives in cementitious systems. In recent years, cellulose nanomaterials in cementitious composites have been extensively investigated, but chitin nanomaterials and starch derivatives for cement and concrete are still emerging research areas. This review article starts with an overview of polysaccharide nanomaterials’ (PNMs) physicochemical properties as a result of different chemical and mechanical extraction processes. Next a brief overview of cement hydration chemistry and microstructure and the interfacial interactions between the cement and the various surface chemical functionalities of PNMs are discussed. Then, the key mechanisms governing the cement strength enhancement by PNMs, such as bridging, nucleating and filling effect, and internal curing, are described. Finally, the impacts of PNMs on other properties of the cement are discussed.

Surface Modification of Decellularized Natural Cellulose Scaffolds with Organosilanes for Bone Tissue Regeneration.

The utility of plant tissues as scaffolding materials has been gaining significant interest in recent years owing to their unique material characteristics that are ideal for tissue regeneration. In this study, the degradation and biocompatibility of natural cellulosic scaffolds derived from Borassus flabellifer (Linn.) (BF) immature endosperm was improved by chemical oxidation and surface functionalization processes. Briefly, thus obtained cellulosic scaffolds were sequentially processed via a detergent exchange decellularization process followed by sodium periodate mediated oxidation and organosilane-based surface modification using amino (NH2)-terminated 3-aminopropyltriethoxysilane (APTES) and methyl (CH3)-terminated octadecyltrichlorosilane (OTS). Post oxidation and surface functionalization, the scaffolds showed improved physiochemical, morphological, and mechanical properties. Especially, the swelling capacity, total porosity, surface area, degradation kinetics, and mechanical behavior of scaffold were significantly higher in modified scaffold groups. The biocompatibility analysis demonstrated excellent cellular adhesion, proliferation and differentiation of osteoblasts with an evident upregulation of mineralization. Subcutaneous implantation of these scaffolds in a rat model demonstrated active angiogenesis, enhanced degradation, and excellent biocompatibility with concomitant deposition of a collagen matrix. Taken together, the native cellulosic scaffolds post chemical oxidation and surface functionalization can exclusively integrate the potential properties of native soft tissue with ameliorated in vitro and in vivo support in bone tissue engineering for nonloading bearing applications.

Lignocellulosic Biomass-Derived Nanocellulose Crystals as Fillers in Membranes for Water and Wastewater Treatment: A Review.

The improvement of membrane applications for wastewater treatment has been a focal point of research in recent times, with a wide variety of efforts being made to enhance the performance, integrity and environmental friendliness of the existing membrane materials. Cellulose nanocrystals (CNCs) are sustainable nanomaterials derived from microorganisms and plants with promising potential in wastewater treatment. Cellulose nanomaterials offer a satisfactory alternative to other environmentally harmful nanomaterials. However, only a few review articles on this important field are available in the open literature, especially in membrane applications for wastewater treatment. This review briefly highlights the circular economy of waste lignocellulosic biomass and the isolation of CNCs from waste lignocellulosic biomass for membrane applications. The surface chemical functionalization technique for the preparation of CNC-based materials with the desired functional groups and properties is outlined. Recent uses of CNC-based materials in membrane applications for wastewater treatment are presented. In addition, the assessment of the environmental impacts of CNCs, cellulose extraction, the production techniques of cellulose products, cellulose product utilization, and their end-of-life disposal are briefly discussed. Furthermore, the challenges and prospects for the development of CNC from waste biomass for application in wastewater treatment are discussed extensively. Finally, this review unraveled some important perceptions on the prospects of CNC-based materials, especially in membrane applications for the treatment of wastewater.

Fabrication and evaluation of antimicrobial biomimetic nanofiber coating for improved dental implant bioseal: An in vitro study.

A weak implant-soft tissue interface may lead to bacterial ingression, breakdown of underlying tissues, and eventually implant failure. This study proposes a surface modification technique of titanium alloy (Ti), using a nano-biopolymer scaffold to enhance soft tissue attachment in dental implants. Gelatin (20% w/v) embedded with 10 ± 2nm silver nanoparticles (AgNPs) was electrospun to form a gelatin electrospun mat (GEM) scaffold, bonded to Ti alloy surface using chemical surface functionalization. Antimicrobial activity of AgNPs was tested against representative Gram-positive (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli) at 4, 24, and 48hours and after embedding in scaffold at 48 hours. Cytotoxicity analysis (MTT assay) was performed using the 3T3 mouse fibroblast cell line at 24 and 72 hours for two groups: control (unmodified Ti disc) and experimental (GEM embedded with AgNPs); and further validated by scanning electron microscopy. The AgNPs-embedded GEM showed good antimicrobial activity at 48 hours, with the AgNPs showing complete (99.99%) inhibition of bacterial colony counts at 24 and 48 hours. Cell viability and proliferation over the GEM modified Ti discs were seen to be significantly increased (P<0.05) at 72 hours as compared with control. SEM images revealed intimate spreading of fibroblasts, with differentiated cell morphology and pseudopodial processes, indicative of enhanced fibroblastic adhesion, growth, and differentiation over the scaffold. Results show good antifouling properties and biocompatibility of the fabricated coating, making it a promising strategy to reduce postoperative infections and peri-implant diseases in Ti dental implants.

Detection of Oenological Polyphenols via QCM-D Measurements.

Polyphenols are a family of compounds present in grapes, musts, and wines. Their dosage is associated with the grape ripening, correct must fermentation, and final wine properties. Owing to their anti-inflammatory properties, they are also relevant for health applications. To date, such compounds are detected mainly via standard chemical analysis, which is costly for constant monitoring and requires a specialized laboratory. Cheap and portable sensors would be desirable to reduce costs and speed up measurements. This paper illustrates the development of strategies for sensor surface chemical functionalization for polyphenol detection. We perform measurements by using a commercial quartz crystal microbalance with dissipation monitoring apparatus. Chemical functionalizations are based on proteins (bovine serum albumin and gelatin type A) or customized peptides derived from istatine-5 and murine salivary protein-5. Commercial oenological additives containing pure gallic tannins or proanthocyanidins, dissolved in water or commercial wine, are used for the analysis. Results indicate that selected functionalizations enable the detection of the two different tannin families, suggesting a relationship between the recorded signal and concentration. Gelatin A also demonstrates the ability to discriminate gallic tannins from proanthocyanidins. Outcomes are promising and pave the way for the exploitation of such devices for precision oenology.

Combining surface chemical functionalization with introducing reactive oxygen species boosts ethanol electrooxidation.

The introduction of functional groups or oxygen vacancies into Pd-based electrocatalysts is a powerful strategy for enhancing the electrocatalytic performances for many electrocatalytic reactions. Herein, an amorphous ceria-modified Pd nanocomposite anchored on D-4-amino-phenylalanine (DAP)-functionalized graphene nanosheets (Pd-CeO2-x/FGS) was prepared by a facile and effective one-pot synthetic strategy and further used as an electrocatalyst for the ethanol oxidation reaction (EOR) in alkaline electrolytes. The obtained Pd-CeO2-x/FGS exhibits relatively high electrocatalytic activity, fast kinetics and excellent antipoisoning ability as well as robust durability for EOR, outperforming the comparable electrocatalysts as well as commercial Pd/C. The experimental results show that the enhanced EOR properties of Pd-CeO2-x/FGS can be attributed to the DAP-functionalization and CeO2-x-modification. Adequate functional groups (amino and carboxyl groups) and abundant oxygen vacancies were introduced in Pd-CeO2-x/FGS by DAP-functionalization and CeO2-x-modification. The functional groups facilitate the anchoring of small nanoparticles onto the substrate as well as modulate the electron density of Pd. The oxygen vacancies boost the adsorption ability of the reactive oxygen species (OHads) and accelerate the kinetics of the potential-limiting step for EOR. This study proposes a new strategy for the rational design of highly efficient catalysts for the electro-oxidation reaction.

Bioactive Coatings on Titanium: A Review on Hydroxylation, Self-Assembled Monolayers (SAMs) and Surface Modification Strategies.

Titanium (Ti) and its alloys have been demonstrated over the last decades to play an important role as inert materials in the field of orthopedic and dental implants. Nevertheless, with the widespread use of Ti, implant-associated rejection issues have arisen. To overcome these problems, antibacterial properties, fast and adequate osseointegration and long-term stability are essential features. Indeed, surface modification is currently presented as a versatile strategy for developing Ti coatings with all these challenging requirements and achieve a successful performance of the implant. Numerous approaches have been investigated to obtain stable and well-organized Ti coatings that promote the tailoring of surface chemical functionalization regardless of the geometry and shape of the implant. However, among all the approaches available in the literature to functionalize the Ti surface, a promising strategy is the combination of surface pre-activation treatments typically followed by the development of intermediate anchoring layers (self-assembled monolayers, SAMs) that serve as the supporting linkage of a final active layer. Therefore, this paper aims to review the latest approaches in the biomedical area to obtain bioactive coatings onto Ti surfaces with a special focus on (i) the most employed methods for Ti surface hydroxylation, (ii) SAMs-mediated active coatings development, and (iii) the latest advances in active agent immobilization and polymeric coatings for controlled release on Ti surfaces.

Distinct Detection of Ganoderma Boninense On Metal Oxides-Gold Nanoparticle Composite Deposited Interdigitated Electrode DNA sensor

Oil palms suffer severe losses due to Ganoderma boninense infection that causes Basal Stem Rot (BSR). The available detection measuring the severity of BSR disease have not proved satisfactory output. Due to the influence of oil palm industry in country’s economy, effective and efficient means of diagnostic measure is mandatory. Among the available diagnostic tools, biosensors were redeemed to yield the most rapid and selective results. To overcome the current issues, herein Interdigitated Electrode (IDE) electrochemical DNA biosensor to detect Ganoderma boninense was successfully designed and fabricated by thermal deposition. Lift-off photolithography fabrication process was applied followed by the surface chemical functionalization via seed deposition. Zinc Oxide (ZnO) and Titanium Dioxide (TiO2) were overlaid and the functionalized metal oxides IDE surfaces were used to detect DNA sequence complementation from Ganoderma boninense. Furthermore, gold nanoparticles were doped to increase the surface to volume ratio and enhance biocompatibility. Characterizations were made by validating the sensor’s topology characteristics and electrical characteristics. From the results recorded, it has been justified that IDE with ZnO doped with gold nanoparticles surface serves as an excellent DNA sensor for the detection of Ganoderma boninense with a remarkable current of 290 nA and 176 nA for immobilization and hybridization respectively.

Efficient Photocatalytic Degradation of Organic Dyes by AgNPs/TiO2/Ti3C2T x MXene Composites under UV and Solar Light.

Due to their broad applications in various industrial activities, and their well-known negative impacts on the aquatic environment, organic dyes have been continuously identified as serious threat to the quality of ecosystems. The photocatalytic degradation process in aqueous solutions has emerged as an efficient and reliable approach for the removal of organic dyes. MXenes, a new class of two-dimensional (2D) nanomaterials, possess unique chemical composition, surface functionalities, and physicochemical properties. Such characteristics enable MXenes to act as efficient catalysts or cocatalysts to photodegrade organic molecules. This work explores the application of Ti3C2Tx MXene decorated with silver and palladium nanoparticles, using a simple hydrothermal treatment method, for the photocatalytic degradation of methylene blue (MB) and rhodamine B (RhB). The chemical composition of these photocatalysts, as well as their structural properties and morphology, was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) techniques. The photocatalytic degradation abilities of the pristine MXene and the synthesized MXene composites were investigated under ultraviolet and solar light irradiation. A significant improvement in the photocatalytic performances was observed for all oxidized MXene composites when compared to pristine MXene, with a superior degradation efficiency achieved for AgNPs/TiO2/Ti3C2Tx. This work broadens the application range of oxidized MXene composites, providing an alternative material for degrading organics dyes and wastewater treatment applications.

Micromechanical Compatibility between Cells and Scaffolds Directs the Phenotypic Transition of Stem Cells

This study experimentally substantiates that the micromechanical compatibility between cell and substrate is essential for cells to achieve energetically favorable mechanotransduction that directs phenotypic transitions. The argument for this compatibility is based on a thermodynamic model that suggests that the response of cells to their substrate mechanical environment is a consequence of the interchange between forms of energy governing the cell-substrate interaction. Experimental validation for the model has been carried out by investigating the osteogenic differentiation of dental follicle stem cells (DFSCs) seeded on electrospun fibrous scaffolds. Electrospinning of blends containing polycaprolactone (PCL) and silk fibroin (SF) with varying composition of cellulose nanocrystals (CNCs) resulted in three-dimensional (3D) fibrous scaffolds with bimodal distribution of fiber diameter, which provides both macroscopically stiff and microscopically compliant scaffolds for cells without affecting the surface chemical functionality of scaffolds. Atomic force microscopy (AFM) with a colloidal probe and single-cell force spectroscopy were used to characterize cell stiffness and scaffold stiffness on the cellular level, as well as cell-scaffold adhesive interaction (chemical functionality). This study has successfully varied scaffold mechanical properties without affecting their surface chemistry. In vitro tests indicate that the micromechanical compatibility between cells and scaffolds has been significantly correlated with mechanosensitive gene expression markers and osteogenic differentiation markers of DFSCs. The agreement between experimental observations and the thermodynamic model affirms that the cellular response to the mechanical environment, though biological in nature, follows the laws of the energy interchange to achieve its self-regulating behavior. More importantly, this study provides systematic evidence, through extensive and rigorous experimental studies, for the first time that rationalizes that micromechanical compatibility is indeed important to the efficacy of regenerative medicine.

Investigation of the role of feedstock properties and process conditions on the slow pyrolysis of biomass in a continuous auger reactor

Slow pyrolysis is a complex process that can convert biomass and waste into valuable products. An improved understanding of the influence of process conditions and feedstocks is required to inform process design and optimisation. A continuous auger reactor (300 g/h) was used to process wheat straw under slow pyrolysis conditions, to study the influence of pyrolysis temperature (400, 500, 600 °C) and solid residence time (3, 6, 10 min) on the product yields and char properties. Production of char decreased with pyrolysis temperature (35.0–26.7 wt%), while gas production increased (15.8–29.7 wt%). The yield of liquid product achieved a maximum of 46.8 wt% at 500 °C. Solid residence time did not affect the product yields significantly. Increasing the pyrolysis temperature produced an increase in the calorific value of the char, mainly through an increase in carbon and fixed carbon (FC) contents and a decrease in oxygen and volatile matter (VM) content. Higher solid residence time caused a reduction in the volatile matter of the char. The surface areas from nitrogen porosimetry at 77 K were very low for all the chars tested (below 15 m2 g−1), suggesting that the pores of the char are blocked or narrowed during operation. FTIR data showed a significant reduction in surface chemical functionalities with pyrolysis temperature, such as C-O and CO, and the solid residence time had no significant effect. The produced chars have the potential to be used as solid fuel, as a soil amendment, or as adsorbents for aqueous phase contaminants. Multiple linear models were developed using literature data to estimate the product yields and properties of the char, including volatile matter, fixed carbon, ash content and higher heating values. The predicted values had a good agreement with the actual values with R2 values in the range of 0.75–0.95. Thus, the models can be used for the design and optimisation of char production by slow pyrolysis.

Nanocellulose-Based Materials for Water Treatment: Adsorption, Photocatalytic Degradation, Disinfection, Antifouling, and Nanofiltration.

Nanocelluloses are promising bio-nano-materials for use as water treatment materials in environmental protection and remediation. Over the past decades, they have been integrated via novel nanoengineering approaches for water treatment processes. This review aims at giving an overview of nanocellulose requirements concerning emerging nanotechnologies of waster treatments and purification, i.e., adsorption, absorption, flocculation, photocatalytic degradation, disinfection, antifouling, ultrafiltration, nanofiltration, and reverse osmosis. Firstly, the nanocellulose synthesis methods (mechanical, physical, chemical, and biological), unique properties (sizes, geometries, and surface chemistry) were presented and their use for capturing and removal of wastewater pollutants was explained. Secondly, different chemical modification approaches surface functionalization (with functional groups, polymers, and nanoparticles) for enhancing the surface chemistry of the nanocellulose for enabling the effective removal of specific pollutants (suspended particles, microorganisms, hazardous metals ions, organic dyes, drugs, pesticides fertilizers, and oils) were highlighted. Thirdly, new fabrication approaches (solution casting, thermal treatment, electrospinning, 3D printing) that integrated nanocelluloses (spherical nanoparticles, nanowhiskers, nanofibers) to produce water treatment materials (individual composite nanoparticles, hydrogels, aerogels, sponges, membranes, and nanopapers) were covered. Finally, the major challenges and future perspectives concerning the applications of nanocellulose based materials in water treatment and purification were highlighted.

Remarkable reduction ability towards p-nitrophenol by a synergistic effect against the aggregation and leaching of palladium nanoparticles in dendritic supported catalysts

The aggregation and leaching of noble metal nanoparticles (NPs) in supported catalysts can decrease or even deactivate the catalytic activity. It is crucial but still challengeable to circumvent these drawbacks. Herein, we facilely synthesize a novel kind of composite nanocatalyst system to conquer these issues of palladium (Pd) NPs. To be specific, nanochannels of dendritic mesoporous silica&titania nanospheres (DMSTNs) could confine Pd NPs. Anatase titania (TiO2) and the coupled mercapto groups (-SH) on the surface could remarkably disperse and robustly anchor Pd. The as-prepared DMSTNs-SH-Pd displays outstanding performance in p-nitrophenol reduction, where a synergistic effect of the chemical composition and surface functionality on the catalytic activity can be further confirmed by photocatalytic water splitting and Suzuki coupling reaction. The strategy for Pd NPs spatially confined in nanochannels and finely decorated on chemically functionalized supports might be versatile for other noble metals like gold (Au), platinum (Pt), etc.

Short-Term to Long-Term Plasticity Transition Behavior of Memristive Devices with Low Power Consumption via Facilitating Ionic Drift of Implanted Lithium

Recent innovations in information technology have encouraged extensive research into the development of future generation memory and computing technologies. Memristive devices based on resistance switching are not only attractive because of their multi-level information storage, but they also display fascinating neuromorphic behaviors. We investigated the basic human brain’s learning and memory algorithm for “memorizing” as a feature for memristive devices based on Li-implanted structures with low power consumption. A topographical and surface chemical functionality analysis of an Li:ITO substrate was conducted to observe its characterization. In addition, a switching mechanism of a memristive device was theoretically studied and associated with ion migrations into a polymeric insulating layer. Biological short-term and long-term memory properties were imitated with the memristive device using low power consumption.

A concise review on design and control of structured natural rubber latex particles as engineering nanocomposites

In this article, we review the modification of natural rubber (NR) latex into the engineered particles for make use of them in functional nanocomposites. The review focuses on tuning nano-/microstructure and/or composition of NR latex particles by means of surface chemical functionalization, structural modification and incorporation of inorganic nanoparticles (NPs). Due to their polydispersity in size and non-spherical shape with complicated indigenous stabilizers, i.e., proteins and lipids, we first describe the fundamental and common methods for the modification of synthetic polymer latex which become a practical guideline for engineering of NR particles to a variety of designs. Subsequently, the examples of successfully modified NR latex and the involved parameters in the preparation are discussed. The different nature and properties of the modified NR latex compared to the synthetic latex are then depicted. Finally, specific examples of these systems used in a range of applications including nanofillers, controlled releasing materials, textiles, electronics and coatings are demonstrated. The research on modification of NR latex particles would be beneficial to the field of materials science and engineering for the valorization of naturally abundant colloidal polymer to the advanced functional materials in the broader utilization/commercialization in the future.

Sulfur-Doped Carbons from Durian Peels, Their Surface Characteristics, and Electrochemical Behaviors.

Durian peels are an agricultural waste in Asian countries, including Thailand, Indonesia, and Malaysia, which can be used as a precursor for the production of activated carbon. The objective of this work is to produce activated carbon from durian peels by chemical activation using sodium sulfite (Na2SO3) as an activating and sulfur-doping agent. The process parameter investigated in this study was the activation temperature (500–900 °C) at a fixed impregnation ratio (durian to activating agent of 1:1, by weight). Specific surface areas and pore structures were determined by nitrogen adsorption and desorption measurements, and elemental compositions were characterized by CHNSO analysis. The chemical structure and surface functionality were examined by X-ray photoelectron spectroscopy. The electrochemical behavior of the obtained activated carbon was characterized in 6 M KOH using a three-electrode configuration. It was found that the sulfur content decreases with activation temperature. In contrast, the specific surface area of the activated carbon increases with activation temperature. However, the sample activated at 900 °C with the highest specific surface area (1499 m2 g–1) has a lower specific capacitance (166 F g–1) than the one activated at 700 °C (183 F g–1). This could be due to the presence of a pseudocapacitance caused by the organic sulfur functional groups such as thiophene, sulfone, and sulfoxide, which can trigger a surface redox reaction, leading to a higher capacitance.