Incorporation Of Silica Nanoparticles Research Articles

Studies on enhanced thermally stable high strength concrete incorporating silica nanoparticles

The performance of silica nanoparticles incorporated high strength concrete (SNPs-HSC) has been evaluated under elevated temperature conditions by exposing up to 800°C, followed by cooling to ambient temperature before performing experiments. Time-temperature studies revealed that incorporation of silica nanoparticles (SNPs) in concrete mix delays the heat transfer by 11%, 18%, 22% and 15% at 200°C, 400°C, 600°C and 800°C respectively thereby, decreasing the rate of degradation as compared to the conventional high strength concrete (HSC). A reduction in weight loss was observed in SNPs-HSC specimens after exposure to 200°C, 600°C, and 800°C; whereas at 400°C the weight loss quantity was ∼3.5% higher than the control HSC specimens due to the evaporation of water from calcium silicate hydrate (C-S-H) gel. On exposure up to 400°C for 2h, the compressive strength and split-tensile strength increased by 40% and 13% respectively, for SNPs-HSC specimens, whereas in control HSC specimen’s strength didn’t increase after 200°C. A higher residual compressive (7%) and split-tensile strength (8%) was found to be in SNPs-HSC specimens exposed to 800°C for 2h as compared to the control HSC specimens. The stress-strain curves revealed that SNPs-HSC specimens exhibits brittle failure up to 600°C whereas in control HSC brittle failure was observed only up to 400°C. Microstructural studies performed on the samples taken from the core of the 400°C exposed SNPs-HSC revealed the formation of higher C-S-H content and lower amount of calcium hydroxide (CH) leading to their enhanced mechanical and thermal stability.

Morphology and thermal properties of HDPE nanocomposites: Effect of spherical silica surface modification and compatibilizer

HDPE composites, filled with 6 wt.% of unmodified (SiO2) or modified spherical nanosilica, containing immobilized silver (Ag-SiO2) or copper (Cu-SiO2) nanoparticles, differing in filler particle size (30, 60 and 90 nm), were prepared by melt mixing using a twin-screw co-rotating extruder. Maleated HDPE (MHDPE) was used to enhance the interaction between silica and polymer matrix, which facilitated the dispersion of silica. The composites were analyzed using scanning and transmitting electron microscopy (SEM, TEM), dynamic-mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). SEM and TEM results revealed that silica nanoparticles aggregates were in general distributed homogenously. DSC results showed that the incorporation of silica nanoparticles could decrease the melting temperature but increase the crystallization temperature, and could lower the crystallinity degree of the HDPE. Moreover, the homogenous distribution of silica particles in the HDPE significantly affected the thermo-oxidative degradation of the composites. Cu-SiO2 particles of 60 nm dimension in the presence of MHDPE showed the best thermal stability, a maximum increment of 86 °C was obtained compared to the pure HDPE. DMTA results were in good agreement with the findings of the morphological and thermal studies.

The addition of silica nanoparticles on the mechanical properties of dental stone

Statement of problemThe current application of nanotechnology in dentistry is limited to nanoparticles incorporated into adhesive systems and composite resins. Dental stone is a widely used material, and the incorporation of silica nanoparticles is still unexplored. PurposeThe purpose of this in vitro study was to evaluate the mechanical properties of dental stone after the addition of silica nanoparticles in different concentrations. Material and methodsA total of 180 specimens were prepared, 90 for each dental stone (Durone and Fuji Rock). For the control group (CG), no silica particles were added, while test group TGnI had silica nanoparticles added to 1 wt%, and test group TGnV had silica nanoparticles added to 5 wt%. The roughness, diametral tensile strength (DTS), and compressive strength were measured 24 hours after the start of spatulation. ResultsThe mean roughness values for Durone were 0.55, 0.36, and 0.28 μm for CG, TGnI, and TGnV; for Fuji Rock, the mean roughness values were 0.47 for CG, 0.31 for TGnI, and 0.35 μm for TGnV. The mean DTS values for Durone were 6.0, 5.1, and 5.0 MPa for CG, TGnI, and TGnV, respectively, and for Fuji Rock, the mean DTS values were 6.4, 5.2, and 4.5 MPa for CG, TGnI, and TGnV, respectively. The mean compressive strength values for Durone were 35.4, 32.7, and 32.4 MPa for CG, TGnI, and TGnV, respectively, and for Fuji Rock, the mean compressive strength values were 42.9, 31.2, and 29.8 MPa for CG, TGnI, and TGnV respectively. ConclusionsSurface roughness was statistically lower for the Durone and Fuji Rock stones (P<.001) when silica nanoparticles were added. The addition of silica nanoparticles did not significantly affect the DTS and compressive strength of Durone compared with CG (P>.05) but did affect the DTS of Fuji Rock when 5 wt% was added and the compressive strength in both concentrations (P<.05).

High strength sustainable concrete using silica nanoparticles

This study deals with the effect of silica nanoparticles (SNPs) in high volume fly ash (40% replacement) cement paste, mortar and concrete. The content of SNPs (0.5–3.0%) was added by the weight of binder and w/b ratio (0.23, 0.25 & 3.0) was optimized in paste and mortar system. The calorimetric results reveal that the hydration process was accelerated as a result of SNPs incorporation and the dormant period was shortening by 4h with 2% SNPs as compared to the control. The effect of optimum dosages of SNPs addition on concrete in terms of mechanical and durability properties was studied at 0.25w/b ratio. The compressive strength results of SNPs added mixtures showed an improvement of 61% at 3days and 25% at 28days of hydration as compared to control. The durability studies at 28day showed that, with the incorporation of SNPs, the porosity, sorptivity and water absorption reduced up to 25–40% and densify the interfacial transition zone (ITZ).

Novel three-dimensional superhydrophobic and strength-enhanced electrospun membranes for long-term membrane distillation

Abstract The practical applications of membrane distillation (MD) are hindered by the absence of effective membranes with high porosity, sufficient strength, and durable wetting repellency for long term operation. In this study, we developed a facile method to construct composite membranes with high MD performance via one-step electrospinning of PVDF solutions blended with hydrophobic silica nanoparticles (NPs). The characterizations reveal that the incorporation of silica NPs have altered the membrane surface morphology and endowed the composite membrane with hierarchical structure on both surface and bulk layers (three-dimensional (3D) superhydrophobic membrane). The hydrophobicity of the membranes can be easily tailored by the dosage of silica NPs, and the water contact angle (WCA) of the membranes can be optimized to be 157 ± 1°, which was close to that of the lotus leaf (160°). Furthermore, the incorporation of silica NPs have promoted the mechanical strength, salt rejection, and water permeation flux of the membranes. The composite membrane containing 7.47 wt% silica NPs (designated as SIL40) can achieve a high MD performance with a water flux of 25.73 kg m −2 h −1 and a permeate conductivity below 5.0 μS cm −1 during a 100 h test-period. The SIL40 also shows a tensile strength and a Young’s modulus of 3.18 and 12.8 MPa, respectively; the values surpassed those of the pristine PVDF membrane (1.5 and 5.4 MPa, respectively). In addition, the MD test indicates that the 3D superhydrophobic membrane exhibits a more durable wetting resistance and a more stable MD performance than the surface-modified superhydrophobic membranes.

Enhanced Performance of Colorimetric Biosensing on Paper Microfluidic Platforms Through Chemical Modification and Incorporation of Nanoparticles.

This chapter describes two different methodologies used to improve the analytical performance of colorimetric paper-based biosensors. Microfluidic paper-based analytical devices (μPADs) have been produced by a stamping process and CO2 laser ablation and modified, respectively, through an oxidation step and incorporation of silica nanoparticles on the paper structure. Both methods are employed in order to overcome the largest problem associated with colorimetric detection, the heterogeneity of the color distribution in the detection zones. The modification steps are necessary to improve the interaction between the paper surface and the selected enzymes. The enhanced performance has ensured reliability for quantitative analysis of clinically relevant compounds.

Synthesis and Characterization of Superhydrophobic, Self-cleaning NIR-reflective Silica Nanoparticles.

Multifunctional coatings offer many advantages towards protecting various surfaces. Here we apply aggregation induced segregation of perylene diimide (PDI) to control the surface morphology and properties of silica nanoparticles. Differentially functionalized PDI was incorporated on the surface of silica nanoparticles through Si-O-Si bonds. The absorption and emission spectra of the resultant functionalised nanoparticles showed monomeric or excimeric peaks based on the amounts of perylene molecules present on the surface of silica nanoparticles. Contact angle measurements on thin films prepared from nanoparticles showed that unfunctionalised nanoparticles were superhydrophilic with a contact angle (CA) of 0°, whereas perylene functionalised silica particles were hydrophobic (CA > 130°) and nanoparticles functionalised with PDI and trimethoxy(octadecyl)silane (TMODS) in an equimolar ratio were superhydrophobic with static CA > 150° and sliding angle (SA) < 10°. In addition, the near infrared (NIR) reflectance properties of PDI incorporated silica nanoparticles can be used to protect various heat sensitive substrates. The concept developed in this paper offers a unique combination of super hydrophobicity, interesting optical properties and NIR reflectance in nanosilica, which could be used for interesting applications such as surface coatings with self-cleaning and NIR reflection properties.

Development of novel biocompatible hybrid nanocomposites based on polyurethane-silica prepared by sol gel process

Due to high biocompatibility, polyurethane has found many applications, particularly in development of biomedical devices. A new nanocomposite based on thermoset polyurethane and silica nanoparticles was synthesized using sol-gel method. Sol-gel process was fulfilled in two acidic and basic conditions by using tetraethylorthosilicate (TEOS) and trimethoxyisocyanatesilane as precursors. The hybrid films characterized for mechanical and surface properties using tensile strength, contact angle, ATR-FTIR and scanning electron microscopy. Biocompatibility and cytotoxicity of the hybrids were assessed using standard MTT, LDH and TUNEL assays. The results revealed that incorporation of silica nanoparticles was significantly improved tensile strength and mechanical properties of the hybrids. Based on the contact angle results, silica nanoparticles increased hydrophilicity of the hybrids. Biocompatibility by using human lung epithelial cell line (MRC-5) demonstrated that the hybrids were significantly less cytotoxic compared to pristine polymer as tested by MTT and LDH assays. TUNEL assay revealed no signs of apoptosis in all tested samples. The results of this study demonstrated that incorporation of silica nanoparticles into polyurethane lead to the enhancement of biocompatibility, indicating that these hybrids could potentially be used in biomedical field in particular as a new coating for medical implants.

Elevating the selectivity of layer-by-layer membranes by in situ bioinspired mineralization

Layer-by-layer (LbL) assembly is a common method for controlled fabrication of ultrathin membranes, while bioinspired mineralization is a novel method for controlled synthesis of well-dispersed inorganic particles in hybrid membranes. Here, bioinspired mineralization was integrated with LbL assembly to prepare ultrathin polymer-inorganic hybrid membranes by in situ precipitating silica nanoparticles into alternatively assembled polyethyleneimine (PEI) and sodium alginate (Alg). The membrane thickness was manipulated by varying the bilayer numbers. And the synthesized silica nanoparticles were revealed by the surface morphology, Si mapping and chemical properties of the membranes. The surface hydrophilicity, diffusion selectivity and the fractional free volume of the hybrid membranes were all enhanced by the incorporation of silica nanoparticles. As a result, the ultrathin hybrid membrane showed elevated selectivity (2.66-fold higher than that of control membrane) with almost unchanged permeability when used for pervaporation dehydration of 90wt% ethanol aqueous solution as a model mixture. This study indicates the great potential for overcoming the tradeoff hurdle between permeability and selectivity by the synergy of LbL assembly and bioinspired mineralization to fabricate ultrathin hybrid membranes.

Compressive Properties of Polylactic Acid-Based Nanocomposite Foams Reinforced with Coconut Fibers

The investigation focused on the properties of composite foam obtained by a compression molding method. The results could clarify the interaction among PLA, silica nanoparticles and coconut fiber. The compressive properties, including the compressive force and modulus of composites, contained in coconut fiber were improved. The incorporation of silica nanoparticles was able to modify the compressive properties slightly, whereas the thermal properties were decreased explicitly. Hydrogen bonding between the carboxylic group of PLA and the silica bonded group affected the increment in mechanical properties of composites. However, the incorporation of coconut fibers in composites exhibited a rougher surface. In addition, beneficial distribution of silica nanoparticles and porosity in the nanocomposite foam, equivalent to neat PLA foam, could be obtained.

Template-Assisted Fabrication of Thin-Film Composite Forward-Osmosis Membrane with Controllable Internal Concentration Polarization

The internal concentration polarization (ICP) of solutes in the porous substrate layer may reduce the water flux of a forward-osmosis (FO) membrane. Here we present an efficient design by using a novel silica template strategy to address this ICP issue. In particular, a thin-film composite (TFC) FO membrane was prepared by incorporating silica nanoparticles (SiNPs) into the poly(ether sulfone) (PES) support layer, followed by the removal of the as-encapsulated SiNPs by hydrofluoric acid (HF) etching, leading to the formation of a highly porous and interconnected-pore structure of the support layer. Such porous structure favors the salt back diffusion in the substrate layer, leading to an improved net osmotic pressure across the selective layer. In addition, the HF treatment also contributes to a more hydrophilic top polyamide layer, further improving the performance of the membrane. The effects of the silica template on the morphology and properties of the as-designed TFC FO membrane are systematically in...

Structure, rheological, thermal conductive and electrical insulating properties of high-performance hybrid epoxy/nanosilica/AgNWs nanocomposites

A facile and effective approach by incorporating silica nanoparticles (SNPs) to fabricate high performance epoxy-based electronic packaging materials which are both thermally conductive and electrically insulating was presented. Because of the strong interaction between SNPs and silver nanowires (AgNWs), uniformly dispersed SNPs-modified epoxy was employed to promote the dispersion of AgNWs in epoxy matrix. Further, the enhanced modulus of epoxy matrix by the incorporation of SNPs effectively alleviates the modulus mismatch between stiff AgNWs and epoxy matrix. Compared with epoxy/AgNWs composites without SNPs, the resulting hybrid materials, that is, epoxy/SNP/AgNWs, showed distinct improvements in thermal conductivity without degrading their mechanical properties. Also, the SNPs were absorbed onto the surface of AgNWs forming an electrical insulation layer to disrupt the electron flows between adjacent AgNWs, hence retaining the electrical insulation of epoxy matrix. Finally, this new fabrication method is easily scalable owing to its simple procedure and use of commercial well-dispersed SNPs-modified epoxies.

UV curing behavior and mechanical properties of unpigmented and pigmented epoxy acrylate/SiO2 nanocomposites

Recently, hybrid organic–inorganic nanocomposite UV-cured coatings have received considerable attention. Their attractiveness is due to improvements in various properties, including resistance to scratch, abrasion, heat, radiation as well as other mechanical and electrical properties, while maintaining their transparency and gloss. In this research, TiO2-pigmented and unpigmented epoxy acrylate/SiO2 nanocomposites were prepared and their curing behavior and mechanical properties were evaluated. For this purpose, photo-DSC and DMA were used. The extent of SiO2 content in samples was chosen in the range of 0–3 h−1. The results showed that the ultimate conversion values increased by 14.1 and 17.6 % when 1- and 3-h−1 silica nanoparticles were added to unpigmented formulation, respectively. On the other hand, the final conversion of TiO2-pigmented formulations increased by 31.7 and 57.1 % using 1- and 3-h−1 silica nanoparticles in the formulations, respectively. These results revealed that the incorporation of silica nanoparticles into pigmented formulations had a more considerable effect comparing to the unpigmented ones. The elastic modulus of unpigmented cured films which had 1- and 3-h−1 silica nanoparticles increased by 21.4 and 23.8 %, respectively, in comparison with the neat sample. The effect of silica nanoparticles on the elastic modulus of pigmented cured films was more considerable, and it increased by 28 and 52 % in comparison with the neat sample when 1- and 3-h−1 silica nanoparticles were incorporated into the formulation. The Tg of nanocomposite samples was found to be higher than that for the neat samples. Once again, it was more significant for the pigmented formulations.

Durable superhydrophilic coatings formed for anti-biofouling and oil–water separation

Building up unique interfaces by means of layer-by-layer (LbL) assembly is of interest for a variety of practical applications, particularly those that require the advantages of special wettability. Herein, a UV-cured superhydrophilic coating with high stability was constructed in the form of a hydrogen-bonding-based LbL multilayer incorporating silica nanoparticles (SNPs). In our present work, hydrophilic branched poly(ethylenimine) (BPEI) and SNPs were assembled into LbL multilayers in the presence of UV-curable poly(urethane acrylate) (PUA), which is described herein as (PUA–SNPs/BPEI)n. The as-prepared architectures showed good acid, thermal, and mechanical stability following crosslinking by UV exposure. Crosslinking is of great importance for LbL film, considering the weak interactions among polyelectrolytes. Owing to the superhydrophilicity of the coating, the anti-biofouling properties were enhanced to some extent for gram-positive Staphylococcus aureus and gram-negative Pseudomonas aeruginosa contamination. Furthermore, the superhydrophilic polycarbonate track-etched (PCTE) membrane coated with (PUA–SNPs/BPEI)n coatings with different numbers of LbL deposition cycles were also investigated for oil–water separation. To the best of our knowledge, this is the first demonstration of rough structures created on a straight pore PCTE membrane. Commercial PCTE membranes with robust coatings, which allow water to penetrate the membrane while oily substance are intercepted, have been developed for regular oil–water separation with more than 99% efficiency.

The effect of silica nanoparticles on the mechanical properties of fiber-reinforced composite resins.

Background. Nanotechnology has introduced many nanoparticles in recent years, which can be incorporated for mechanical improvement of dental materials. However, the existing data are widely sparse. This study investigated the reinforcing effect of silica nanoparticles when incorporated into the matrix phase of an experimental dental fiber-reinforced compositeresin (FRC) through evaluation of its flexural properties.Methods. In this experimental study FRC samples were divided into two main groups (containing two or three bundles),either of whic consisted of five subgroups with 0, 0.2, 0.5, 2 and 5 wt% of silica nanoparticles in the matrix resin (n=10 in each subgroup); a commercial FRC (Angelus, Brazil) was used as the control group (n=10). Three-point bending test was performed to evaluate the flexural strength and modulus. Thereafter, the microstructure of the fractured samples was evalu-ated using scanning electron microscopy (SEM). The results were analyzed with one-way ANOVA and HSD Tukey tests (α = 0.05).Results. The results revealed that the silica nanoparticles had a significant and positive effect on the flexural strength and modulus of FRCs (P<0.05), with no significant differences from 0.2 to 5 wt% of nanoparticles (P > 0.05) in either group with two or three bundles of fibers.Conclusion. Incorporating silica nanoparticles into the FRC resin phase resulted in improved flexural strength and modulus of the final product.

Quantification of hydration products in cementitious materials incorporating silica nanoparticles

In the present work, silica nanoparticles (30-70nm) were supplemented into cement paste to study their influence on degree of hydration, porosity and formation of different type of calcium-silicate-hydrate (C-S-H) gel. As the hydration time proceeds, the degree of hydration reach to 76% in nano-modified cement paste whereas plain cement achieve up to 63% at 28 days. An influence of degree of hydration on the porosity was also determined. In plain cement paste, the capillary porosity at 1hr is ~48%, whereas in silica nanoparticles added cement is ~35 % only, it revealed that silica nanoparticles refines the pore structure due to accelerated hydration mechanism leading to denser microstructure. Similarly, increasing gel porosity reveals the formation of more C-S-H gel. Furthermore, C-S-H gel of different Ca/Si ratio in hydrated cement paste was quantified using X-ray diffractometer and thermogravimetry. The results show that in presence of silica nanoparticles, ~24% C-S-H (Ca/Si<1.0) forms, leading to the formation of polymerised and compact C-S-H. In case of plain cement this type of C-S-H was completely absent at 28 days. These studies reveal that the hydration mechanism of the cement can be tuned with the incorporation of silica nanoparticles and thus, producing more durable cementitious materials.

Effect of silica nanoparticles on the interfacial properties of a canonical lipid mixture

The incorporation of silica nanoparticles (NPs) from the subphase into Langmuir lipid monolayers formed by three components, 1,2-Dipalmitoyl-sn-glycerol-3-phosphocholine (DPPC), 1,2-Dioleoyl-sn-glycero-3-phosphocholine (DOPC) and Cholesterol (Chol), modifies the thermodynamic and rheological behavior, as well as the structure of the pristine lipid film. Thus, the combination of structural characterization techniques, such as Brewster Angle Microscopy (BAM) and Atomic Force Microscopy (AFM), with interfacial thermodynamic and dilational rheology studies has allowed us to deepen on the physico-chemical bases governing the interaction between lipid molecules and NPs. The penetration of NPs driven by the interaction (electrostatic or hydrogen bonds) with the polar groups of the lipid molecules affects the phase behaviour (surface pressure-area, П−A , isotherm) of the monolayer. This can be easily rationalized considering the modification of the packing and cohesion of the molecules at the interface as revealed BAM and AFM images. Furthermore, oscillatory barrier experiments have allowed obtaining information related to the effect of NPs on the monolayer response under dynamic conditions that presents a critical impact on the characterization of biological relevant systems because most of the processes of interest for these systems present a dynamic character.

Effect of silica nanoparticles in mixed matrix membranes for pervaporation dehydration of acetic acid aqueous solution: plant-inspired dewatering systems

Clean technology in dehydration of acetic acid using pervaporative separations inspired by plant dewatering systems is studied in this work. The novel polyphenylsulfone-based membranes, modified with silica nanoparticles, were used to dehydrate a binary mixture of acetic acid and water. The Stöber process was applied for the synthesis of monodispersed silica colloids by hydrolysis of alkyl silicates and condensation of silicic acid in alcoholic solution. The surface free energy of the synthesized silica particles was altered through a silanization treatment with hexamethyldisilazane to convert the surface hydroxyl groups to trimethylsilyl[–Si(CH3)3] groups. The synthesized particles and the modified polyphenylsulfone based membranes were characterized using dynamic light scattering, scanning electron microscopy, atomic force microscopy, Fourier-transform infrared and macroscopic contact angle measurements. Pervaporation was used for the dehydration of 70 wt% acetic acid at 70 °C using nine different membrane variations. Inspired by the natural dewatering in plants containing silica, the performance of the synthetic silica nanoparticles filled-membranes was investigated. Similar to plants, the incorporation of silica nanoparticles in these membranes significantly affected the dewatering process. It was found that at higher concentrations of silica, an improvement of membrane properties was observed, particularly in terms of selectivity. Besides that, the hydrophilicity and surface roughness increases when sufficient amounts of silanols groups were present on the membrane surface. It was concluded that more hydrophilic silica should be first produced and incorporated into the membranes for efficient removal of water from acetic acid. This can be achieved by controlling the composition ratio of ammonium hydroxide, water and ethanol for the nanoparticle fabrication. The effect of different nanoparticle types on membrane morphology and pervaporation performance is also discussed in detail in this work.

Improved interfacial properties between glass fibers and tetra-functional epoxy resins modified with silica nanoparticles

The interfacial properties between fiber bundle and polymer matrix play a crucial role in determining the final performance of fiber-reinforced polymer composites. Epoxy modified with nanofillers as new “matrix” for the composites has been shown to be a possibility to enhance the interfacial properties between fiber bundle and “matrix”. Herein, we synthesized silica nanoparticles with an average diameter of ~80 nm through using the sol-gel technique and achieved a good dispersion of silica in tetra-functional epoxy matrix after intensively mechanical mixing procedure. The results revealed that incorporation of silica nanoparticles into epoxy increased its stiffness, strength and toughness simultaneously. Such silica/epoxy composite as new “matrix” showed a good impregnation in the fiber bundles, and thus produced improved interfacial properties between glass fiber bundle and new “matrix”. For example, the presence of 15.0 wt% silica nanoparticles was found to produce ~15 %, 22 % and ~34 % in the elastic modulus, tensile strength and critical stress intensity factor of epoxy, respectively; and the interfacial strength between fiber bundle and the “matrix” was also enhanced by ~58.3 %. Based on the fracture surface analysis, several possible mechanisms were proposed and discussed to understand the improved interfacial properties between glass fiber bundle and tetra-functional epoxy modified with silica nanoparticles.

Versatile Self‐Cleaning Coating Production Through Sol–Gel Chemistry

The performance of optical devices is dependent on their optical transparency (OT). This is evident when such devices are exposed to environmental conditions that can reduce OT. The development of a robust, transparent and self‐cleaning coating is highly desirable, for applications likeoptical windows and solar panels. This work reports the design of such coatings based on a hydrophobic thin film fabricated using a sol‐gel process. Coating properties were optimised by modification of the surface topography of the coatings, achieved by the incorporation of silica nanoparticles(NPs). The coating was characterised by water contact angle(WCA), scanning electron microscopy(SEM) and white light interferometry (WLI). The efficacy and robustness of the coating foroptical application was assessed.