Hydrophilic Surface Chemistry Research Articles

Titanium Implant Surface Effects on Adherent Macrophage Phenotype: A Systematic Review.

Immunomodulatory biomaterials have the potential to stimulate an immune response able to promote constructive and functional tissue remodeling responses as opposed to persistent inflammation and scar tissue formation. As such, the controlled activation of macrophages and modulation of their phenotype through implant surface modification has emerged as a key therapeutic strategy. Methods: Online databases were searched for in vitro studies between January 1991 and June 2020 which examined the effect of titanium implant surface topography on the adherent macrophage phenotype at either the gene or protein level. Results: Thirty-nine studies were subsequently included for review. Although there was significant heterogeneity between studies, treatment of titanium surfaces increased the surface roughness or hydrophilicity, and hence increased macrophage attachment but decreased cell spreading. Physical coating of the titanium surface also tended to promote the formation of cell clusters. Titanium and titanium-zirconium alloy with a micro- or nano-scale rough topography combined with a hydrophilic surface chemistry were the most effective surfaces for inducing an anti-inflammatory phenotype in adherent macrophages, as indicated by significant changes in cytokine gene expression and or cytokine secretion profiles. Conclusions: The published data support the hypothesis that incorporation of specific topographical and physiochemical surface modifications to titanium can modulate the phenotypic response of adherent macrophages.

Biotemplated synthesis of hollow nickel silicate fiber for organic dye contaminants and its selective adsorption

Silicate is one kind of the fundamental constituent of minerals with the interesting properties, such as environment-friendliness, easily availability and hydrophilic surface chemistry. In this study, cotton fiber as versatile biotemplate is employed to synthesize hollow nickel silicate fibers through hydrothermal treatment and carbonization removal of the template. The as-prepared hollow nickel silicate fiber is rich in hydroxyl group and mesoporous structure according to the characterization of SEM、FTIR、XRD and N2 adsoprtion-desorption measurement. The adsorption performance of hollow nickel silicate fiber for methylene blue (MB) and congo red (CR) dye from the aqueous solution is systematically investigated. The results show that the dye adsorption of HNiSiFs for MB and CR is in accordance with the pseudo-second-order kinetic model, and Langmuir isotherm model is predominant for the monolayer adsorption process with the maximum adsorption capacity of 195.7 and 414.9 mg g−1 for MB and CR, respectively. Moreover, the as-prepared hollow nickel silicate fiber can selectively adsorb anionic dye containing N group from the mixed anionic pollutant solution. The electrostatic interaction of cationic organic molecular or molecular containing N group with HNiSiFs is the main driving force for the effective and specific adsorption.

Highly efficient Cr(VI) remediation by cationic functionalized nanocellulose beads

Applications of nanocellulose as a water treatment material are being actively pursued based on its interesting properties, such as renewability, large specific surface area, hydrophilic surface chemistry, and biodegradability. This study used carboxymethyl cellulose nanofibrils (CMCNFs) to prepare a typical bead-type adsorbent with improved structural stability as an actual water treatment restoration material. In addition, a cationized nanocellulose adsorbent was prepared by introducing polyethyleneimine (PEI) on the surface of the CMCNF (P/CMCNF), the removal efficiency of Cr(VI) was evaluated, and its mechanism was elucidated. As a result, the P/CMCNF beads showed an excellent Cr(VI) removal capacity of 1302.3 mg/g, the best result among cellulose-based adsorption materials. Cr(VI) was effectively removed by electrostatic attractions combined with chemical reduction and chelation mechanisms. Furthermore, the macrobead fabrication and PEI surface modification process improved the underwater stability of the P/CMCNF, and it showed excellent reuse efficiency.

Demineralization of high ash coal fines of Indian origin using Mahua oil

The cost of oil is perhaps the biggest prohibitive aspect of the oil agglomeration process. Furthermore, the high ash low grade coals of India are more difficult to demineralize owing to their unfavourable hydrophilic surface chemistry. The objective of our present study is to use an indigenous and underutilized oil derived from Mahua seeds as a potential bridging liquid for oil agglomeration of low grade coal from Kaniha (Odisha, India) with 35% ash. Based on experimental results, Mahua oil demonstrably proved efficient in demineralization by 45–50% at lower oil concentrations (10–15 wt%), devoid of surfactants. Wet grinding of the coal using a vibratory cup mill was an essential pre-treatment step. A detailed investigation of all the crucial process parameters was performed through variation of pH, oil dosages, solid to liquid ratio and agitation conditions. The results obtained were further validated by detailed characterization of both raw and clean coal using zeta potential, FTIR, SEM studies and petrography. FTIR and petrographic studies validated the inherent and surface hydrophilicity of Kaniha coal. Zeta potential studies clearly showed an increase in surface potential around neutral pΗ which was found to be optimum for oil agglomeration. SEM results conclusively supported the formation of porous large size agglomerates. To our knowledge, ours is the first thorough examination of agglomeration potential of Mahua oil, which is an industrially underutilized product, thus supporting the aim of waste utilization and cleaner fuel production. • Crude Mahua oil as bridging liquid for oil agglomeration of high ash low grade Indian coal (35% ash) has been investigated. • Lower dosage (15 wt%) of oil under neutral conditions gave satisfactory results. • Wet grinding in a vibratory cup mill has been implicated to be a crucial pre-treatment step. • Demineralization by 45–50% was observed. • No pre-conditioning step of surfactant was included.

Demineralization of high ash non-coking coal fines of Indian origin using Castor oil: Implications of wet milling

ABSTRACT The high-ash low-grade coals of Indian origin are relatively more challenging to demineralize due to their unfavorable hydrophilic surface chemistry. Herein, we report castor oil as a potential bridging liquid, which efficiently agglomerated high-ash low-grade coals by 55–60% at lower concentration (10 wt%) compared to literature (20–25 wt%), without inclusion of surfactants. A blend of castor oil and turpentine oil proved further beneficial. Wet milling of coal was a crucial prerequisite for efficient agglomeration. Three low-grade coals, Bhubaneshwari (35.8% ash), Kaniha (35% ash), and Hingula (26% ash), were beneficiated in the present study. A detailed analysis of process parameters validated with structural characterization using FTIR, Petrography, zeta potential, and SEM analysis was performed. The chemistry between ricinoleic acid in castor oil with that of surface functionality of coal is speculated to be the reason behind the obtained agglomeration results. Castor oil, being non-edible, bio-based, non-toxic, and non-polluting in nature, provides a greener alternative to mineral oils toward the production of clean fuel.

Nanoscale Curvature of Nanocellulose Paper Promotes High Yield Spontaneous Formation of Giant Vesicles

Giant unilamellar vesicles (GUVs) have proven to be instrumental tools for a variety of biophysical experiments including among others, lipid membrane organization, membrane protein function, cytoskeleton mechanics, membrane division. To date, techniques to obtain adequate yields of vesicles require the application of electric fields or dissolution of molecules during growth and quantitative comparisons of the vesicles produced across these different growth conditions is unclear. In this work, we report quantitative measurements that i) show the nanoscale curvature and hydrophilic surface chemistry of nanocellulose paper promotes the highest yields of GUVs when compared to the other most commonly used techniques and ii) lead to the development of a thermodynamic model that unifies our observations and provides mechanistic insight into the growth process. The results from this work show the exciting potential of nanocellulose paper as a simple and scalable platform to manufacture large quantities of GUVs for biophysical interrogation as well as to open avenues in drug delivery and synthetic cells.

Disentangling the role of surface topography and intrinsic wettability in the prey capture mechanism of Nepenthes pitcher plants

Nepenthes pitcher plants capture prey with leaves specialised as pitfall traps. Insects are trapped when they ‘aquaplane’ on the pitcher rim (peristome), a surface structured with macroscopic and microscopic radial ridges. What is the functional significance of this hierarchical surface topography? Here, we use insect pad friction measurements, photolithography, wetting experiments and physical modelling to demonstrate that the ridges enhance the trap's efficacy by satisfying two functional demands on prey capture: Macroscopic ridges restrict lateral but enhance radial spreading of water, thereby creating continuous slippery tracks which facilitate prey capture when little water is present. Microscopic ridges, in turn, ensure that the water film between insect pad and peristome remains stable, causing insects to aquaplane. In combination, the hierarchical ridge structure hence renders the peristome wettable, and water films continuous, so avoiding the need for a strongly hydrophilic surface chemistry, which would compromise resistance to desiccation and attract detrimental contamination.

Hierarchical Mesoporous MXene-NiCoP Electrocatalyst for Water-Splitting.

The utilization of nonprecious metal electrocatalysts for water-splitting may be the ultimate solution for sustainable and clean hydrogen energy. MXene, an emerging two-dimensional material, exhibits many unique properties such as possible metal-like conductivity, hydrophilic surface, and rich chemistry, rendering a group of promising catalysts and catalyst support materials. In this study, exfoliated Ti3C2 MXenes serve as a substrate to perpendicularly grow uniform mesoporous NiCoP nanosheets through an in situ interface-growth strategy and subsequent phosphorization. The obtained Ti3C2@mNiCoP materials with a stable hierarchical sandwich structure possess excellent conductivity, large surface area, and uniform mesopores with high pore volume. With these beneficial properties, the Ti3C2@mNiCoP material exhibits superior overall water-splitting performance compared with that of its building-block counterparts, matching the state-of-the-art water-splitting electrocatalysts.

Effect of silica nanoparticles on the impregnation process, foaming dynamics and cell microstructure of styrene-methyl methacrylate copolymer/n-pentane foams

In the present study, two-step foaming procedure with a designed in-situ foaming observation apparatus was used to study the foaming dynamics of styrene-methyl methacrylate (St-MMA) copolymer/nanosilica composites. For this purpose, the St-MMA copolymer was synthesized using suspension copolymerization and its nanocomposites were prepared using solution method. The foaming dynamics was studied through temperature-induced (two-step batch foaming) method. Furthermore, the effects of content, size and surface chemistry of silica nanoparticles on the impregnation process, the foaming dynamics and the final morphology of prepared foams were investigated. The impregnation data showed that the presence of silica nanoparticles in matrix prolonged the impregnation and decreased diffusion coefficient. This effect would be clearer where nanoparticle contents are high and the temperature is quite above Tg. The foaming dynamics results illustrated that the nucleation and foaming rate were enhanced with the nanoparticle addition and its size reduction. At the St-MMA copolymer foaming system, the silica nanoparticles with hydrophilic surface chemistry are more efficient in comparison to hydrophobic nanoparticles where all foaming dynamics and the final microstructure parameters were improved.

Adsorption of volatile organic compounds by industrial porous materials: Impact of relative humidity

Abstract In this study, the adsorption of several classes of volatile organic compounds by materials with a range of pore size distributions and chemistries were assessed gravimetrically in both dry and wet carrier gas conditions. Measurements carried out at room temperature, and a range of relative humidity values (RH) from 0 to 70%, reflected real-world conditions similar to those of indoor air. Dry removal performance appeared to be dependent on the surface area of adsorbents and, for polar compounds, the relative hydrophobicity of the material. Performance of sorbents with hydrophilic surface chemistry, such as silica gel and molecular sieve 13X, decreased drastically with small increases in pre-exposed humidity. Activated charcoal and high-silica faujasite Y retained their capacities for toluene in relative humidities up to 50% and 70% respectively, with their selectivity for non-polar species credited to hydrophobic pore structure and low water vapour uptake. These conclusions help to emphasise the importance of process humidity as a key parameter when designing or selecting adsorbents in realistic process conditions. Additionally, the methods used in this study provide a simple and reproducible way of testing porous materials for applications requiring or involving high levels of relative humidity.

Hydration Layer Structure of Biofouling-Resistant Nanoparticles.

Hydrophilic surface chemistries can strongly bind water to produce surfaces that are highly resistant to protein adsorption and fouling. The interfacial bound water and its distinct properties have intrigued researchers for decades, yet the relationship between the water three-dimensional structure and function in antifouling coatings remains elusive. Here, we use hydrophilic, epoxy organosilane modified silica nanoparticles to demonstrate cheap, robust, and practically applied coatings that we discover have broad-ranging, ultralow fouling properties when challenged by various proteins, bacteria, and fungal spores. To understand their excellent antifouling properties, frequency modulation-atomic force microscopy is used to directly observe the interfacial water structure at subatomic resolution, which we validate using all-atom molecular dynamic simulations that strikingly predict similar structures of water layers on the original and ultralow fouling surfaces. The convergence of experimental and modeling data reveals that suitably spaced, flexible chains with hydrophilic groups interact with water molecules to produce a connective, quasi-stable layer, consisting of dynamic interfacial water, that provides a basis for antifouling performance of ultrathin, hydrophilic surface chemistries.

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

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

Effect of oxygen plasma treatment and gold sputtering on morphological and local mechanical properties of copolyimide/gold micropatterned structures

Atomic force microscopy (AFM) was used to analyze rectangular 3‐dimensional patterned microstructures with different functionalities induced on copolyimide containing alicyclic sequences film surfaces by means of oxygen plasma treatment. The plasma power was ranged to be big enough to accelerate the plasma species towards the copolyimide surface, and the exposure time was not very small to generate a roughness that still can be monitored by AFM. To create the rectangular pattern, transmission electron microscopy grid masks were placed on the samples before treatment. Plasma‐induced micropatterning with alternating hydrophilic and hydrophobic surface chemistries was evaluated by measuring the adhesion forces between the gold‐covered AFM tip and the copolyimide surfaces. To fabricate 3‐dimensional metallic microstructures arranged in well‐defined areas, thin metal layers were sputtered on these pretreated copolyimide films. The AFM morphological aspects of the obtained metallic structures were correlated with the surface modifications induced by plasma treatment conditions. Functional indexes and functional volume parameters were also calculate to characterize the functional behavior of the surface, such as wear, lubrication, and contact. The AFM data were compared with those obtained using the small‐angle X‐ray scattering measurements.

Stabilizing the MXenes by Carbon Nanoplating for Developing Hierarchical Nanohybrids with Efficient Lithium Storage and Hydrogen Evolution Capability.

The MXenes combining hydrophilic surface, metallic conductivity and rich surface chemistries represent a new family of 2D materials with widespread applications. However, their poor oxygen resistance causes a great loss of electronic properties and surface reactivity, which significantly inhibits the fabrication, the understanding of the chemical nature and full exploitation of the potential of MXene-based materials. Herein we report a facile carbon nanoplating strategy for efficiently stabilizing the MXenes against structural degradation caused by spontaneous oxidation, which provides a material platform for developing MXene-based materials with attractive structure and properties. Hierarchical MoS2 /Ti3 C2 -MXene@C nanohybrids with excellent structural stability, electrical properties and strong interfacial coupling are fabricated by assembling carbon coated few-layered MoS2 nanoplates on carbon-stabilized Ti3 C2 MXene, exhibiting exceptional performance for Li storage and hydrogen evolution reaction (HER). Remarkably, ultra-long cycle life of 3000 cycles with high capacities but extremely slow capacity loss of 0.0016% per cycle is achieved for Li storage at a very high rate of 20 A g-1 . They are also highly active HER electrocatalyst with very positive onset potential, low overpotential and long-term stability in acidic solution. Superb properties highlight the great promise of MXene-based materials in cornerstone applications of energy storage and conversion.

Antifouling Electrospun Nanofiber Mats Functionalized with Polymer Zwitterions.

In this study, we exploit the excellent fouling resistance of polymer zwitterions and present electrospun nanofiber mats surface functionalized with poly(2-methacryloyloxyethyl phosphorylcholine) (polyMPC). This zwitterionic polymer coating maximizes the accessibility of the zwitterion to effectively limit biofouling on nanofiber membranes. Two facile, scalable methods yielded a coating on cellulose nanofibers: (i) a two-step sequential deposition featuring dopamine polymerization followed by the physioadsorption of polyMPC, and (ii) a one-step codeposition of polydopamine (PDA) with polyMPC. While the sequential and codeposited nanofiber mat assemblies have an equivalent average fiber diameter, hydrophilic contact angle, surface chemistry, and stability, the topography of nanofibers prepared by codeposition were smoother. Protein and microbial antifouling performance of the zwitterion modified nanofiber mats along with two controls, cellulose (unmodified) and PDA coated nanofiber mats were evaluated by dynamic protein fouling and prolonged bacterial exposure. Following 21 days of exposure to bovine serum albumin, the sequential nanofiber mats significantly resisted protein fouling, as indicated by their 95% flux recovery ratio in a water flux experiment, a 300% improvement over the cellulose nanofiber mats. When challenged with two model microbes Escherichia coli and Staphylococcus aureus for 24 h, both zwitterion modifications demonstrated superior fouling resistance by statistically reducing microbial attachment over the two controls. This study demonstrates that, by decorating the surfaces of chemically and mechanically robust cellulose nanofiber mats with polyMPC, we can generate high performance, free-standing nanofiber mats that hold potential in applications where antifouling materials are imperative, such as tissue engineering scaffolds and water purification technologies.

In vitro evaluation of osteoblast responses to carbon nanotube-coated titanium surfaces.

BackgroundThe effects of surface roughness and carboxyl functionalization of multi-walled carbon nanotubes (MWCNTs) mixed with collagen coated onto titanium (Ti) substrates on MC3T3-E1 osteoblasts were evaluated.MethodsThe proliferation, differentiation, and matrix mineralization were investigated using (1) smooth-surfaced Ti discs, (2) Ti discs coated with collagen and MWCNT (Ti-MWCNT), and (3) Ti discs coated with collagen and MWCNT-COOH (Ti-MWCNT-COOH) for applications in orthodontic mini screw implants (MSIs). The coatings were uniform when analyzed using scanning electron microscopy (SEM), and surface roughness was evaluated by surface profilometry that demonstrated similar surface roughness (Ra, mean ± SD) in the MWCNT (0.83 ± 0.02 μm) and MWCNT-COOH (0.84 ± 0.01 μm) groups. MTT (3-(4,5-dimethylthiazol-2-Yl)-2,5-diphenyltetrazolium bromide) assay was performed after days 1, 3, and 7 to assess proliferation. Alkaline phosphatase (ALP)-specific activity was assessed after day 7 to quantify differentiation. Alizarin red staining was measured after day 28 to quantify matrix mineralization. All data were analyzed with JMP Pro11 software (SAS, USA) with a statistical significance of p < 0.05.ResultsSurface profilometry demonstrated similar surface roughness (Ra, mean ± SD) in the MWCNT (0.83 ± 0.02 μm) and MWCNT-COOH (0.84 ± 0.01 μm) groups. On day 7, ALP assay showed that MWCNT-COOH (mean ± SD 0.98 ± 0.26 U/μg of protein) enhanced cell differentiation when compared to the uncoated group (p = 0.05). Alizarin red staining after 28 days of cell culture revealed that MWCNT-COOH (mean ± SD 1.5 ± 0.2 OD405) increased (p = 0.03) matrix mineralization when compared to the uncoated group (0.9 ± 0.09 OD405).ConclusionsThis study showed that coatings containing MWCNT-COOH (increased hydrophilic surface chemistry) influence osteoblast proliferation, differentiation, and matrix mineralization and should be further studied for applications in orthodontic MSIs.

Unusual ultra-hydrophilic, porous carbon cuboids for atmospheric-water capture.

There is significant interest in high-performance materials that can directly and efficiently capture water vapor, particularly from air. Herein, we report a class of novel porous carbon cuboids with unusual ultra-hydrophilic properties, over which the synergistic effects between surface heterogeneity and micropore architecture is maximized, leading to the best atmospheric water-capture performance among porous carbons to date, with a water capacity of up to 9.82 mmol g(-1) at P/P0 =0.2 and 25 °C (20% relative humidity or 6000 ppm). Benefiting from properties, such as defined morphology, narrow pore size distribution, and high heterogeneity, this series of functional carbons may serve as model materials for fundamental research on carbon chemistry and the advance of new types of materials for water-vapor capture as well as other applications requiring combined highly hydrophilic surface chemistry, developed hierarchical porosity, and excellent stability.

Enzymatic preparation of nanocrystalline and microcrystalline cellulose

Traditional cellulose nanocrystal (CNC) production methods use harsh chemicals, are energetically expensive, and result in a hydrophilic sulfate surface chemistry with limited utility. Enzymatic production of CNCs is a less expensive alternative production method that eliminates the need for harsh chemicals and requires much less energy for mechanical fibrillation and heating. Furthermore, enzymes that selectively degrade the amorphous regions of cellulose fibers, and do not significantly digest the crystalline areas, result in CNCs that retain a hydroxyl group surface chemistry. Retention of hydroxyl groups allows for easier chemical manipulation, and thus an expanded commercial potential. Here we show that cellulase from Aspergillus niger is capable of producing CNC and microfibrillated cellulose (MFC) from well-solubilized kraft pulp feedstock with minimal processing, and that a chimeric cellulase partially digests kraft pulp and live wood feedstock. Additionally, we show that as a feedstock source, milled pulp from bug-killed dead and downed trees has significantly reduced energy requirements to process the feedstock into elementary fibers and MFCs when compared to live wood feedstock sources.

Self-assembly of lipopolysaccharide layers on allantoin crystals

Self-assembly of lipopolysaccharides (LPS) on solid surfaces is important for the study of bacterial membranes, but has not been possible due to technical difficulties and the lack of suitable solid supports. Recently we found that crystals of the natural compound allantoin selectively bind pure LPS with sub-nanomolar affinity. The physicochemical origins of this selectivity and the adsorption mode of LPS on allantoin crystals remain, however, unknown. In this study we present evidence that LPS adsorption on allantoin crystals is initiated through hydrogen-bond attachment of hydrophilic LPS regions. Hydrophobic interactions between alkyl chains of adjacently adsorbed LPS molecules subsequently promote self-assembly of LPS layers. The essential role of hydrogen-bond interactions is corroborated by our finding that allantoin crystals bind to practically any hydrophilic surface chemistry. Binding contributions of hydrophobic interactions between LPS alkyl chains are evidenced by the endothermic nature of the adsorption process and explain why the binding affinity for LPS is several orders of magnitude higher than for proteins (lysozyme, BSA and IgG) and polysaccharides. Self-assembly of LPS layers via hydrogen-bond attachment on allantoin crystals emerges as a novel binding mechanism and could be considered as a practical method for preparing biomimetic membranes on a solid support.

Antibacterial Flexible Biaxially Oriented Polyethylene Terephthalate Sheets Through Sequential Diazonium and Hydrophilic Polymer Surface Chemistries

Antibacterial Flexible Biaxially Oriented Polyethylene Terephthalate Sheets Through Sequential Diazonium and Hydrophilic Polymer Surface Chemistries