Role Of Surface Modification Research Articles

Factors Determining Unique Thermal Resistance and Surface Properties of Silicone-Containing Composites.

This review discusses the key factors influencing the exceptional thermal resistance and surface properties of silicone-containing composites. Silicone polymers, known for their excellent chemical and physical properties, are widely used in a number of innovative products. In order to make silicone composites suitable for innovative applications, it is essential to ensure that they have both very good thermal resistance and superhydrophobic properties. Identification of the key factors influencing these properties enables the use of these composites in coatings, electronics and photovoltaic panels. The discussion includes the role of organosilicon polymer structures and the incorporation of micro- and nanoadditives to enhance the performance of these materials. Different methods for the modification and production of silicone composites are analyzed, with an emphasis on achieving thermal stability and surface superhydrophobicity simultaneously. The review highlights the growing demand for silicone-based coatings due to technological advances and environmental concerns. Furthermore, the role of surface modification and hierarchical surface structures in achieving these unique properties is discussed, as well as the potential applications and challenges in the development of next-generation silicone-containing materials.

Enhanced structural stability and durability in lithium-rich manganese-based oxide via surface double-coupling engineering

Lithium-rich manganese-based oxides (LRMOs) exhibit high theoretical energy densities, making them a prominent class of cathode materials for lithium-ion batteries. However, the performance of these layered cathodes often declines because of capacity fading during cycling. This decline is primarily attributed to anisotropic lattice strain and oxygen release from cathode surfaces. Given notable structural transformations, complex redox reactions, and detrimental interface side reactions in LRMOs, the development of a single modification approach that addresses bulk and surface issues is challenging. Therefore, this study introduces a surface double-coupling engineering strategy that mitigates bulk strain and reduces surface side reactions. The internal spinel-like phase coating layer, featuring three-dimensional (3D) lithium-ion diffusion channels, effectively blocks oxygen release from the cathode surface and mitigates lattice strain. In addition, the external Li3PO4 coating layer, noted for its superior corrosion resistance, enhances the interfacial lithium transport and inhibits the dissolution of surface transition metals. Notably, the spinel phase, as excellent interlayer, securely anchors Li3PO4 to the bulk lattice and suppresses oxygen release from lattices. Consequently, these modifications considerably boost structural stability and durability, achieving an impressive capacity retention of 83.4% and a minimal voltage decay of 1.49 mV per cycle after 150 cycles at 1 C. These findings provide crucial mechanistic insights into the role of surface modifications and guide the development of high-capacity cathodes with enhanced cyclability.

Functionalization of fabrics by Ag-TiO2 Nanoparticles deposition by sol-gel method

Nanotechnology's expanding global applications, especially in textiles, integrate various disciplines within textile engineering. Research primarily concentrates on incorporating nanomaterials, like titanium dioxide and silver, into textile substrates for enhanced functionalities such as self-cleaning, UV protection, and antimicrobial properties. Metal oxide nanoparticles, particularly Ag and TiO2, exhibit remarkable efficacy in combating microorganisms. Sol-gel techniques play a crucial role in surface modification, facilitating better adhesion of nanomaterials and enabling diverse applications in materials science. This study focuses on utilizing silver and titanium nanoparticles for antimicrobial and dirt-repellent properties in lightweight fabrics, showcasing a preliminary step towards uniform incorporation for subsequent evaluation.

Facile formation of surface functionalised α-Fe2O3 nanoparticles and their role in developing dual sensors towards cysteamine quantification

The innovative one step method employed here for the synthesis and surface modification of α-Fe2O3 is equally efficient and viable. The role of surface modification in maximising the output is obvious as terephthalic acid (TPA) crowned Fe2O3 (T-Fe2O3) nanoparticles exhibited better electrochemical properties than bare Fe2O3 when employed as an electrode modifier. It is first time, cysteamine sensors based on T-Fe2O3 nanoparticles were developed and displayed great response in terms of widest linear range, improved selectivity and sensitivity. When combined with glassy carbon electrode (GCE), the sensor achieved broad linear range from 8 µM to 3732 µM which is superior than reported till now. The sensor illustrated with disposable Screen printed electrode (SPE) exhibited widest linear range from 25 to 3900 µM with great linearity in a single calibration graph attributed by the high sensitivity of SPE. The results obtained with SPE lead pathway for designing of portable sensors.

Thermal Performance of Silver Nanoparticle-Enhanced Nanofluids in Heat Pipe Systems: The Role of Surface Modifications

Thermal Performance of Silver Nanoparticle-Enhanced Nanofluids in Heat Pipe Systems: The Role of Surface Modifications

Removal of fine solids from bitumen by hetero-aggregation and magnetic separation using surface-modified magnetite nanoparticles. Part 2: Role of surface modification

Stearylamine acetate (SAA) modified magnetite nanoparticles (MNPs) have been previously proven to significantly improve the efficiency of fine solids removal from cyclohexane-diluted non-aqueous extracted (NAE) bitumen following magnetic separation. In this work, asphaltene-modified magnetite nanoparticles (Asp-MNPs) were prepared, and their ability to remove fine solids from NAE bitumen was evaluated. The influence of the surface modification with SAA or asphaltene on MNPs in their interactions with NAE fine solids was studied through quartz crystal microbalance with dissipation monitoring and atomic force microscopy studies. It was demonstrated that modification by SAA increased the adhesion interaction between the MNPs and NAE fine solids through a bridging effect. The use of an external magnetic field also strengthened the hetero-aggregation between surface-modified MNPs and the NAE fine solids. Though the asphaltene modification of MNPs resulted in a repulsive behavior in the interaction between MNPs and NAE fine solids due to steric effect, the applied external magnetic field could drive the Asp-MNPs together and induce the bridging among the Asp-MNPs through an interdigitation process, and the NAE fine solids could be captured through a sweeping effect by the networked Asp-MNPs.

Inhibition of non-specific protein adsorption on PMMA surface: The role of surface modification

Mitigating non-specific adsorption (NSA) occurring on the surface of microfluidic devices plays a critical role in the detection of early protein biomarkers for clinical diagnosis. Surface-modified methods commonly used in the formation of microfluidic channels include BSA coating, PEG grafting, and Plasma cleaning. The surface composition and microstructure of PMMA surfaces were characterized by Fourier transfer infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), water contact angles (CA), and atomic force microscopy (AFM) measurements. The NSA on surfaces of bovine serum albumin (BSA) labeled with fluorescein isothiocyanate (FITC) were investigated by microfluidics and fluorescence microscopy. The results showed that the hydrophobicity of the PMMA surface was enhanced after modification with PEG. We further evaluated their anti-protein adsorption properties under a mild alkaline (PH 7.4) condition, including concentration, reaction time, and sample volume. The BSA coating had the best anti-protein adsorption effect, reaching over 87.6%. The anti-protein adsorption effect of the plasma cleaning method is slightly inferior to that of BSA coating, at 86.1%, but the modification process is simpler and faster. Due to the insufficient stability of PEG, its resistance to protein adsorption decreases as the concentration increases.

Preparation of PTFE particles-doped manganese phosphating coatings on 20Cr steel and their wear and corrosion resistance

Different PTFE particles-doped manganese phosphating coatings were prepared by changing the concentration of PTFE particles in a phosphating solution with 20Cr steel as the substrate commonly used for gears manufacturing. The experimental results show that the grain of different manganese phosphating coatings are polyhedral and irregularly distributed, with the size of 6–15 µm. PTFE particles in the manganese phosphating coating play a filling role in effectively blocking the penetration of corrosive medium and act as a solid lubricating medium to reduce friction in the friction process. Changing the concentration of PTFE particles in the phosphating solution has little effect on the grain growth, compactness and hardness of PTFE particles-doped manganese phosphating coating, but affects the wear resistance and corrosion resistance of PTFE particles-doped manganese phosphating coating. When the concentration of PTFE particles in the phosphating solution is 20 g/L, the PTFE particles in the manganese phosphating coating is 6.86 %. The phosphating coating prepared under the condition of 20 g/L PTFE particles in the phosphating solution has the lowest friction coefficient of 0.41, the lowest corrosion current density of 9.6 × 10−7 A/cm2, and the most positive corrosion potential of −552.4 mV, showing excellent wear resistance and corrosion resistance, which can play a good role in surface modification of 20Cr steel.

Damage Effect of Amorphous Carbon Black Nanoparticle Aggregates on Model Phospholipid Membranes: Surface Charge, Exposure Concentration and Time Dependence.

Commercial nano-scale carbon blacks (CB) are being harnessed widely and may impose potentially hazardous effects because of their unique properties, especially if they have been modified to grow reactive functional groups on their surface. Cytotoxicity of CB has been well studied but the membrane damage mechanisms and role of surface modification are still open to debate. Negatively and positively charged giant unilamellar vesicles (GUVs) were prepared using three lipids as model cell membranes to examine the mechanistic damage of CB and MCB (modified by acidic potassium permanganate) aggregates. Optical images showed that both anionic CB and MCB disrupted the positively charged but not the negatively charged GUVs. This disruption deteriorated with the rise and extension of exposure concentration and time. Lipids extraction caused by CBNs (CB and MCB together are called CBNs) was found. MCB caused more severe disruption than CB. MCB was enveloped into vesicles through an endocytosis-like process at 120 mg/L. MCB mediated the gelation of GUVs, perhaps through C-O-P bonding bridges. The lower hydrodynamic diameter and more negative charges may have been responsible for the distinction effect of MCB over CB. The adhesion and bonding of CBNs to the membrane were favored by electrostatic interaction and the practical application of CBNs warrants more attention.

Synthesis, characterization, and application of microporous biochar prepared from Pterospermum acerifolium plant fruit shell waste for methylene blue dye adsorption: the role of surface modification by SDS surfactant

Synthesis, characterization, and application of microporous biochar prepared from Pterospermum acerifolium plant fruit shell waste for methylene blue dye adsorption: the role of surface modification by SDS surfactant

Fundamental Insight into the Role of Surface Modification on Cycling Stability and Fast Charge Performance of Ceramic Lib Cathodes

There are numerous promising ceramic cathodes for lithium ion batteries (LIBs), ranging from established fast-charge LFP to emerging high voltage low-Co or Co-free materials. Their fast charge and cycling performance can be greatly enhanced with various ceramic and/or carbon coatings. This presentation discusses coating approaches for several cathode systems, focusing on their effect on the microstructural stability during cycling. Advanced transmission electron microscopy (TEM) is the primary tool employed, combined with various syntheses, analytical and electroanalytical methods. For example, analysis is performed on the role of Zr surface modification on the electrochemical performance of Li and Mn-rich (LMR) cathodes. It is demonstrated that a Zr-based rock-salt structure layer with a thickness of 1−2 nm is formed on the surface of the LMR. This layer is effective in suppressing the deleterious phase transformation of LMR from initial layered composite combining Li2MO3 and LiMO2 to the disordered rock-salt phase, leading to an enhanced long-term cycling performance and rate capability. The capacity-voltage fade phenomenon in lithium iron phosphate (LiFePO4) cathodes is not understood, with this study providing the first atomic-scale description: Cycling causes near-surface (∼ 30 nm) amorphization of the Olivine crystal structure, with isolated amorphous regions also being present deeper in the bulk crystal. Within this amorphous shell, some of the Fe2+ is transformed into Fe3+. Simulations predict that amorphization significantly impedes ion diffusion in LiFePO4 and even more severely in FePO4. A pyrrole coating suppresses the dissolution of Fe and allows for extended retention of the Olivine structure. It also reduces the level of crossover of iron to the metal anode and stabilizes its solid electrolyte interphase, thus also contributing to the half-cell cycling stability.

(Invited) Microstructural Design Principles and Fundamental Insight for Achieving Stable Electrochemical Interfaces for Metal Anodes and for Ceramic Cathodes

Lithium metal battery systems (LMBs) are being sought as an ultimate replacement to LIBs, potentially increasing the cell energy by over fifty percent due to the high capacity and low voltage of the metal anode. Analogous improvement in energy is possible with sodium metal batteries (NMBs) and with potassium metal batteries (KMBs), where existing ion insertion anodes can be replaced by plating/stripping metal. However, in all three cases safety and performance are compromised by an unstable solid electrolyte interphase (SEI) that consumes metal ions and electrolyte, and ultimately leads to dendrites. This presentation provides a series of case studies derived from the group's LMB, NMB and KMB research on the microstructural design principles that provide for long-term cycling and fast-charge stability of metal anodes. The approaches may be categorized as the following: a) design of plating/stripping supports and templates with tuned geometry and functionality; b) design of secondary interlayers placed between the metal anode and the separator; and c) design of multifunctional hybrid separators to replace the conventional polymer separators employed with LIBs. It is demonstrated that despite appearing distinct, the efficacy of each in enabling electrochemical stability originates from three fundamental features that are directly interrelated. The wetting behavior of the electrolyte on the anode must be optimized, the wetting/stripping behavior of the metal anode on the current collector must be controlled, and a geometrically and chemically modified SEI must be established. Simultaneously achieving all three leads to stable plating/stripping, while missing even one leads to rapid dendrite growth. There seems to be no exceptions to these rules with either Li, Na or K. In parallel this presentation will discuss fundamental insights into the role of surface modification on cycling stability and fast charge performance of ceramic LIB cathodes. Advanced transmission electron microscopy (TEM) was the primary tool employed, combined with various syntheses, analytical and electroanalytical methods. For example, analysis is performed on the role of Zr surface modification on the electrochemical performance of Li and Mn-rich (LMR) cathodes. The capacity-voltage fade phenomenon in LFP cathodes is not understood, with this study providing the first atomic-scale description of the process. It is demonstrated how a pyrrole coating suppresses the dissolution of Fe and allows for extended retention of the Olivine structure. It also reduces the level of crossover of iron to the metal anode and stabilizes its solid electrolyte interphase, thus also contributing to the half-cell cycling stability. These findings were recently published in Advanced Materials, Energy & Environmental Science, Advanced Energy Materials and Chemistry of Materials.

Robust superhydrophobic fabric via UV-accelerated atmospheric deposition of polydopamine and silver nanoparticles for solar evaporation and water/oil separation

Polydopamine (PDA) inspired by mussel plays a unique role in surface modification due to its strong adhesion to virtually all kinds of materials and the subsequent functionality. However, the deposition of PDA and its subsequent metallization in bulk solution is slow and thus the surface modification based on PDA is not efficient. Herein, by atmospheric deposition with the aid of ultraviolet (UV) irradiation, a process is proposed to facilitate the fast deposition of PDA and silver nanpparticles (Ag NPs) on cotton fabric. The word “fast” means that efficiency of the overall deposition is increased by 45 times. Fabric with PDA and Ag NPs is further modified by dodecyl mercaptan (DT) and turns to be superhydrophobic. Ag NPs play multiple roles in the fabrication and application of the superhydrophobic fabric, viz., enhancing the hydrophobicity and photothermal effect of the fabric. Due to its superhydrophobicity and excellent photothermal effect, the fabric floating on water can harvest solar energy to facilitate the local evaporation of seawater. The evaporation rate is 1.66 kg/(m2·h) and the solar energy conversion efficiency is 91%. As the oil–water separation membrane, the separation efficiency of oil–water mixture is more than 96%, and the oil flux is more than 12 m3·m−2·h−1. Overall, this is a story from sea to sea. PDA inspired by the sea creature of mussel is quickly deposited on the fabric and serves as a platform for further deposition of silver and modification with DT, and the so-obtained superhydrophobic sample can be used to solve the marine problems such as solar evaporation and oil/water separation.

Facile hydrothermal synthesis of SnO2 quantum dots with enhanced photocatalytic degradation activity: Role of surface modification with chloroacetic acid

Designing high-performance noble-metal-free photocatalysts is the key for photocatalytic technology to expand its further application in energy and environment fields. Herein, chloroacetic acid (CA) modified SnO2 quantum dots (QDs) with enhanced photocatalytic activity were prepared under hydrothermal conditions. Through XRD, TEM, FT-IR XPS, Raman and TG analysis, it was found that CA molecules were successfully linked to the surface of SnO2 QDs and formed stable SnO2@CA QDs. The SnO2@CA QDs show excellent photocatalytic activities for methyl orange, methylene blue and phenol. The photocatalytic degradation of methyl orange follows the first order reaction. From the apparent rate constant, it can be seen that the photocatalytic performances of SnO2 QDs were significantly improved by the modification of CA, while decreased with the increase of hydrothermal reaction time. Finally, the preliminary hypothesis of SnO2@CA QDs for degradation of organic pollutants has been proposed. The findings reported here could benefit the designing of highly efficient photocatalyst.

Hyperbranched polyester modified graphene oxide on anti-corrosion performance of epoxy composite coatings for electric power system

ABSTRACT In this study, the hyperbranched polyester (HBP) was grafted onto the surface of graphene oxide (GO) to prepare functionalised GO (fGO). Results of X-ray photoelectron spectra, Thermogravimetric analysis, Fourier transform infrared spectroscopy and Transmission Electron Microscopy confirmed the success of grafting. Moreover, the anti-corrosion performance and barrier properties of the bare steel, and steel with epoxy (EP) coating, steel coated with EP/GO and EP/fGO were comparatively studied. It was found that EP/fGO showed enhanced anti-corrosion capability and barrier properties to H2O and O2 compared with EP/GO, attributed to the surface modification of GO by HBP. Moreover, the role of surface modification using HBP on the performance of EP/GO composite coating was also discussed, related mechanism was proposed.

Exploration of interactions of ‘blood-nano interface’ of carbon-based nanomaterials for biomedical applications

Abstract

Adsorption characteristics of molecular oxytetracycline onto alumina particles: The role of surface modification with an anionic surfactant

The present study investigated the adsorption of molecular oxytetracycline (OTC) from aqueous solution onto surfactant-modified alumina (SMA). An anionic surfactant, sodium dodecyl sulfate (SDS), which was used to modify the alumina surface at high ionic strength induced a significant increase in the removal efficiency of OTC. Some conditions that were effective for the removal of OTC using SMA such as contact time, pH, adsorbent dosage, and ionic strength were systematically studied. The optimum contact time was 180 min, while the pH of the solution, adsorbent dosage and ionic strength were found to be 4, 25 mg/mL and 1 mM NaCl, respectively. The highest removal efficiency for OTC using SMA was >97%. Under the optimal adsorption conditions, OTC removal from an actual water sample collected from shrimp aquaculture achieved a very high removal efficiency of 90%. After the adsorbent was regenerated four times, the removal efficiency of OTC using SMA was still higher than 83%. A two-step adsorption model was successfully applied to fit the experimental results of OTC adsorption isotherms onto SMA at different ionic strengths, while the adsorption kinetics of OTC onto SMA followed a pseudo-second order model. The maximum adsorption capacity of OTC onto SMA was found to be 143 mg/g. The adsorption of OTC onto SMA decreased with the increasing NaCl concentration and pH because the SDS desorption out of the alumina surface was enhanced with an increase in salt concentration and pH. The adsorption mechanisms of OTC onto SMA were discussed in detail based on Fourier transform infrared (FT-IR) spectroscopy, zeta potential measurements, adsorption isotherms of OTC and SDS desorption upon OTC adsorption. Our results demonstrate that the surface modification of alumina with SDS is important to form a novel adsorbent for the removal of tetracycline antibiotics from aqueous solution.

Transport of the arsenic (As)-loaded nano zero-valent iron in groundwater-saturated sand columns: Roles of surface modification and As loading

In this study, the effects of surface modification of nZVI and arsenic (As) loading on the mobility of the three types of As-loaded nZVI (As-loaded pristine, chitosan-modified and polyaniline-modified nZVI) in quartz sand-packed columns were investigated. Breakthrough curves and retention profiles for the three types of As-loaded nZVI were analyzed by the Tufenkji-Elimelech equations and the HYDRUS-1D model. The mobility of both types of As-loaded modified nZVI was higher than the As-loaded pristine nZVI at both low and high As loadings. Compared to low As loading, the mobility of the three types of As-loaded nZVI was higher at high As loading. The values of the calculated and the fitted retention parameters of the three As-loaded nZVI were lower when As loading was higher or nZVI was modified, which were in line with the experimental column findings. The mechanisms of As-loaded nZVI transport were probably due to ripening and sedimentation. The As in the effluent was mainly from the As-loaded nZVI particles when nZVI was detected and was from the As release when no nZVI was detectable. It was evident that the mobility of the three types of As-loaded nZVI particles were severely limited (the maximum transport distance was less than 60 cm), regardless of surface modification and As loading. Therefore, the As release from the As-loaded nZVI could cause potentially wide pollution and should be paid more attention regarding to the application of nZVI in As remediation.

Investigations on structural and electrical properties of polyaniline–cadmium sulfide nanocomposite films for solid state electronics

Conducting polyaniline (PANI)/cadmium sulfide (CdS) nanocomposite films were prepared by in situ chemical oxidation method. The prepared nanocomposites were characterized by fourier transform infra‐red spectroscopy, X‐ray diffraction, and scanning electron microscopy for structural and morphological analysis. The effect of CdS content on structural and morphological features of PANI matrix are discussed in detail. The frequency dependent room temperature conductivity and dielectric properties of these composites were studied by measuring various parameters in the frequency range 10–106 Hz. The role of surface modification on electrical and dielectric properties of the composites was analyzed and it was found that, the concentration of CdS in PANI matrix has a greater influence on electrical properties due to the alteration of molecular chains in PANI matrix. Among various nanocomposites so prepared, the composite with 3 wt% of CdS in PANI matrix (P3) shows better conductivity and dielectric behavior which could be of great importance in various technological applications. The possibility of these materials being used as transistors, energy storage and nano dielectric devices could be explored further. POLYM. COMPOS., 40:E579–E588, 2019. © 2018 Society of Plastics Engineers

Crater Formation on the Surface of Pure Metal and Alloy Irradiated by High Current Pulsed Electron Beam

Abstract A detailed investigation concerning the formation mechanism of craters of pure metal and alloy surface after high-current pulsed electron beam (HCPEB) processing has been carried out. After HCPEB irradiation, typical craters were homogeneously distributed on the entire surface of 3Cr13 stainless steel, resulting from local sublayer melting and eruption through the solid outer surface. Comparatively, almost no craters were created of pure zirconium, which was associated with the shallow melting site and incomplete treated surface. Furthermore, a large number of ultrafine grains were formed on the irradiated surface, indicating that surface melting was the dominant interaction mechanism between HCPEB irradiation and pure zirconium. It is apparent that “crater free” phenomenon plays a dominant role in surface modification of zirconium and zirconium alloys.