Silica Glass Surface Research Articles

Fabrication of Fresnel zone plate lens in fused silica glass using femtosecond laser lithography technology

This paper expresses maskless formation of Fresnel zone plate (FZP) lens on fused silica glass surface using femtosecond laser lithography technology. The FZP lens consists of a series of concentric rings that has been encoded on a glass surface using femtosecond laser irradiation followed by chemical etching and stripping. To compare the performance of the FZP lens with traditional laser induced FZP, we also fabricated FZP on the surface of and inside fused silica glass using femtosecond laser direct writing. In all the cases, the FZP lenses have a focal length of 50 mm. In addition, we fabricated a 25-mm focal length FZP lens by means of femtosecond laser lithography. Compared to traditional femtosecond laser direct writing, femtosecond laser lithography technique offers smooth patterning of materials. Consequently, femtosecond laser lithography engraved FZP lens yields considerably higher diffraction efficiency. Besides, we investigated the diffraction pattern of the fabricated FZP lenses. Using these FZP lenses, we are able to observe microletters encoded on an aluminum coated poly-methylmethacrylate surface indicating excellent focusing and imaging capability of the FZP lenses. The proposed maskless technology is simple compared to other lithography techniques, representing great potential for small-scale manufacturing of similar kinds of optical/photonics devices.

Determination of orientation and adsorption-induced changes in the tertiary structure of proteins on material surfaces by chemical modification and peptide mapping

The labeling of amino acid residues followed by peptide mapping via mass spectrometry (AAL/MS) is a promising technique to provide detailed information on the adsorption-induced changes in its solvent accessibility. However, the potential of this method for the study of adsorbed protein structure is largely undeveloped at this time. The objective of this research was therefore to extend these capabilities by developing and applying AAL/MS techniques for a range of amino acid types to identify the dominant configurations of an adsorbed protein on a material surface. In this study, the configuration of hen egg white lysozyme (HEWL) adsorbed on fused silica glass, high-density polyethylene (HDPE) and poly(methyl methacrylate) (PMMA) was mapped by combining the labeling profiles obtained from five amino acid labels, which were independently applied. In order to be able to combine the results from the different amino acid labeling processes, the intensity of the HEWL segment without the target amino acids was used as an internal control to normalize the intensity shifts to an equivalent level. The resulting quantitative differences in the normalized amino acid profiles were then used to provide insights into adsorbed orientation, protein–protein interactions and adsorption-induced tertiary unfolding of HEWL, which were found to be distinctly different between the fused silica glass, HDPE and PMMA surfaces. The developed technique has the potential for broad application and for expansion to additional targeted amino acids to provide highly detailed information on the adsorbed state of any protein on any given surface.

Glass Surface Refining by Deposition of Nano-Particles

In the paper a new surface refining technology which uses nano-particles to improve the soda – lime – silica glass surfaces is presented. The SEM-EDS (Energy Dispersive X-ray Spectrometry) analysis was carried out to determine modification of the glass surface. A very thin modification layer was observed on the glass surface. The surface modification leads to an improvement of physical and chemical properties of the investigated glass.

Errata: Improvement of magnetorheological finishing surface quality by nanoparticle jet polishing

This article [Opt. Eng.. 52, (4 ), 043401 (2013)] was originally published on 15 April 2013 with an error on page 6, Sec. 4, paragraph 2. The first sentence “Figure 8 shows the AFM image of surface microstructure images of 10×10 μm on the silica glass surface…” has been corrected to read “Figure 8 shows the AFM image of surface microstructure images of 5×5 μm on the silica glass surface…”

Surface characterization of silica glass substrates treated by atomic hydrogen

Silica glass substrates with very flat surfaces were exposed to atomic hydrogen at different temperatures and durations. An atomic force microscope was used to measure root-mean-square (RMS) roughness and two-dimensional power spectral density (PSD). In the treatment with atomic hydrogen up to 900°C, there was no significant change in the surface. By the treatment at 1000°C, the changes in the RMS roughness and the PSD curves were observed. It was suggested that these changes were caused by etching due to reactions of atomic hydrogen with surface silica. By analysis based on the k-correlation model, it was found that the spatial frequency of the asperities became higher with an increase of the treatment time. Furthermore, the data showed that atomic hydrogen can flatten silica glass surfaces by controlling heat-treatment conditions.

Study of damage initiation in SiO2 glass and ceramics by fractoluminescence and acoustic emission techniques

The results of high-rate detection of fractoluminescence (FL) and acoustic emission (AE) induced by the shock destruction of the surface of silica glass and silica ceramics are presented. The FL arises as a result of breaking covalent bonds, and the growing microscopic and larger cracks are a source of AE. The intensities of FL and AE are proportional to the energy released by the follow of defects. It is shown that the energy distribution of the energy in the FL signals registered after the shock follows the power law characteristic for cooperative processes in nonequilibrium thermodynamic systems. Qualitatively similar results were obtained for a ceramics not subjected to high-temperature treatment, sintered ceramics, and monolithic glass. This means that the damage initiation at the nanostructural level is always a correlated process. In the series of AE signals, the power law distribution of the energy was found only for sintered ceramics. Cooperative phenomena in AE generation are not observed for unsintered ceramics and silica glass.

Fabrication of Combined One-Dimensional and Three-Dimensional Structure of Potassium Tungstate Crystal Layers by Spray Deposition with Polystyrene Colloidal Crystal Templates

Well-aligned honeycomb-designed layers of potassium tungstate (K0.33WO3.165) were successfully fabricated by spray deposition and microsphere lithography using polystyrene (PS) colloidal crystals as templates. A densely packed monolayer of monodisperse PS microspheres was formed on a silica glass surface, using the Langmuir–Blodgett thin film technique. Subsequently, a (NH4)10W12O41·5H2O-KCl aqueous solution was sprayed as a micromist on the PS templates. While the K0.33WO3.165 crystal layers were synthesized by chemical reaction between W and K sources during the heating, the PS templates were thermally decomposed, generating an inverse opal surface structure where the interstitial space of the densely hexagonal packed PS microspheres had been. Numerous hexagonal rodlike crystals were grown on the honeycomb-designed layer of K0.33WO3.165. X-ray diffraction analysis, energy-dispersive X-ray spectroscopy analyses, and X-ray photoelectron spectroscopy were performed to analyze the combined one-dimensional and three-dimensional honeycomb-designed structure.

An easy way to obtain thin gold film on silica glass substrate by chemical method

Physical methods of metal deposition under ultra-high vacuum conditions are currently used to manufacture electrically conductive surfaces. In the case of silica glass, a supplementary oxide layer is usually required to avoid the uncontrolled growth of metal nanoparticles on the surface. Here, we present a simple chemical method which allows the formation of a high density of small gold nanoparticles forming a film on bare silica glass surface. The deposition of gold takes place at ambient pressure and in water followed by a thermal treatment that leads to the formation a gold film of 6nm thickness according to atomic force microscopy experiments. This film consists of juxtaposed nanoparticles, which insures electrical conductivity under vacuum, as attested by the possibility of doing scanning electron microscopy imaging without carbon coating.

Fabrication of curved PDMS microstructures on silica glass by proton beam writing aimed for micro-lens arrays on transparent substrates

Polydimethylsiloxane (PDMS), a type of silicone rubber, has excellent material properties such as flexibility, optical transparency and biocompatibility. Therefore, it can offer possible applications in the field of microfluidics as flexible micro-optical components, when they can be formed on transparent materials such as silica glass. We performed proton beam writing (PBW) (with 1.0MeV beam) on PDMS microstructures with curved surface on silica glass. We found that 13-μm thick PDMS films on silica glass are sensitive only for proton fluences above 600nC/mm2 in contrast with the sensitivity of 4.0nC/mm2 when using a silicon substrate. Based on the hypothesis that the effective sensitivity was lower due to the electric charging of silica glass surface during PBW, we coated the silica glass surface by Au sputtering. As a result, we were able to observe the formation of PDMS on the Au-coated silica glass at a much lower fluence of 2.0nC/mm2. Arrays of curved PDMS structures with a height of 13μm and diameter of 40μm have been fabricated on a semi-transparent Au-coated silica glass.

Adherence of Molecules to Silica Glass Surface: Experimental Results and Theoretical Calculations

Abstract The adherence of molecules to surfaces is used in a wide scope of technological applications. In this work we study the attachment of molecules onto porous silica glass surface obtained from a Vycor glass, after glass- glass phase separation and leaching of the soluble phase with water. Nitrogen adsorption at 77 K was used for the determination of the specific surface area (BET area) and pore size distribution on the leached glass. The adherence onto the glass surface, of model molecules methylene blue (MB) and eosine yellow (EY), with positive and negative electrical charges respectively, was studied. The adsorption kinetics was determined from aqueous solutions using UV-VIS spectroscopy. It was found that the silica glass surface as prepared in this work is selective for positively charged molecules at pH≈5.20, an adsorption of 1 mg MB per gram of glass was found for methylene blue, and almost null adsorption for eosine yellow. First principles calculations were performed using the Density Functional Theory in order to model the interaction between both molecules and the glass surface.

Synthesis of periodic plasmonic microstructures with copper nanoparticles in silica glass by low-energy ion implantation

Ion implantation was used to locally modify the surface of silica glass to create periodic plasmonic microstructures with Cu nanoparticles. Nanoparticles were synthesized by Cu-ion irradiation of the silica glass at the ion energy of 40 keV, dose of 5×1016 ions/cm2 and current density of 5 μA/cm2. This procedure involves low-energy ion implantation into the glass through a mask placed at the surface. Formation of nanoparticles was observed by optical spectroscopy and atomic force microscopy. The presented results clearly demonstrate how the low-energy ions can be used for the fabrication of photonic microstructures on dielectric surfaces in a single-step process.

Nanostructures synthesis by femtosecond laser ablation of glasses

In this article, we investigate the variations in ablation dynamics that result in diverse nanostructures on SiO2 based glass samples. A three-dimensional fibrous nanoparticle agglomerate was observed on sodalime glass when exposed to femtosecond laser irradiation. The fused nanoparticles have diameters ranging from 30 nm to 70 nm. Long continuous nanofibers of extremely high aspect ratio (certain fibers up to 100 000:1) were obtained by exposing silica glass surface to femtosecond laser irradiation at MHz repetition rate in air. A nanostructure assembly comprising of nanofiber and nanoparticle agglomerates was also observed by ablating silica glass. From our experimental analysis, it was determined that variation in bandgap and material composition alters ablation dynamics and dictates the response of glass to femtosecond laser irradiation, ultimately leading to the formation of structures with varying morphology on silica and sodalime glass. The possible underlying mechanisms that produce such nanostructures on glass specimens have also been explored.

Quantitative Fractography of Mixed‐Mode Fracture in Soda Lime Silica Glass

Fracture surfaces of soda lime silica glass failed from controlled surface cracks in diametral compression, under mixed‐mode loading conditions were studied using fractography. Mode mixity was introduced by orienting indent precracks in different directions with respect to the loading axis. The mixed‐mode fracture surfaces were characterized by an absence of the mist region. The hackle markings on the mixed‐mode fracture surfaces appear as lances and differ from those observed on surfaces failed in pure mode I. Atomic force microscopy on the mixed‐mode fracture surfaces revealed that the features at different regions are similar and differ only by scale. Fracture surface measurements for mixed‐mode loading are compared to the measurements for mode I loading. The stress intensity at microbranching was determined to be a constant irrespective of the loading conditions. The practical implications of these observations are that forensic analyses can be used without a priori knowledge of the loading conditions.

Contact charging of silica glass particles in a single collision

Based on asymmetric contact, we present a contact charge model of high-energy trapped holes to predict the contact charging and explain the net charge transfer between identical silica glass surfaces in a single normal collision. Furthermore, the contact charging measurements are investigated on normal collisions of glassy particle-glassy particle-steel plane and glassy particle-glassy plane. The predicted results agree well with our experiments qualitatively and quantitatively: the impacting velocity and the particle size are two important factors affecting the magnitude of the contact charging.

Development of a tuned interfacial force field parameter set for the simulation of protein adsorption to silica glass.

Adsorption free energies for eight host-guest peptides (TGTG-X-GTGT, with X = N, D, G, K, F, T, W, and V) on two different silica surfaces [quartz (100) and silica glass] were calculated using umbrella sampling and replica exchange molecular dynamics and compared with experimental values determined by atomic force microscopy. Using the CHARMM force field, adsorption free energies were found to be overestimated (i.e., too strongly adsorbing) by about 5-9 kcal/mol compared to the experimental data for both types of silica surfaces. Peptide adsorption behavior for the silica glass surface was then adjusted using a modified version of the CHARMM program, which we call dual force-field CHARMM, which allows separate sets of nonbonded parameters (i.e., partial charge and Lennard-Jones parameters) to be used to represent intra-phase and inter-phase interactions within a given molecular system. Using this program, interfacial force field (IFF) parameters for the peptide-silica glass systems were corrected to obtain adsorption free energies within about 0.5 kcal/mol of their respective experimental values, while IFF tuning for the quartz (100) surface remains for future work. The tuned IFF parameter set for silica glass will subsequently be used for simulations of protein adsorption behavior on silica glass with greater confidence in the balance between relative adsorption affinities of amino acid residues and the aqueous solution for the silica glass surface.

Effect of Water Corrosion on Cracks and Vickers Imprints in Glass

Erosion and corrosion result in potential material loss. The erosion is a physical phenomenon but corrosion is chemical one. The study of these two phenomena, as functions of time and temperature, would lead to a better understanding of glass surface damage. Results allow one to determine the effects of immersion time, temperature of the water bath and residual stresses generated by Vickers indentation on the radial crack and topography of the imprint on the surface of a soda-lime silica glass. Water corrosion effects are different at the imprint corner and the radial crack tip as compared to edges and faces.

Precise XPS depth analysis of soda–lime–silica glass surface after various treatments

Ar ion sputtering is one of the most accepted techniques for depth profiling in practical XPS analysis, although this technique is known to be inadequate for quantitative analysis of glass including mobile ions such as soda–lime–silica glass. Buckminsterfullerene (C60) ion sputtering has recently been recognized to suppress the composition change of glass and the degradation of organic materials. Here, C60 ion sputtering was applied to examine the change of the compositional depth profile on soda–lime–silica glass (70.4SiO2, 0.9Al2O3, 7.3MgO, 7.8CaO, 13.6Na2O in mol%) surface in detail because of various treatments such as annealing, washing, polishing, and storage. The precise analysis revealed that the sodium profile changed variously within 30 nm depth. Copyright © 2012 John Wiley & Sons, Ltd.

Pressure solution – The importance of the electrochemical surface potentials

“Pressure solution”, frequently found in clay-rich sandstone, is characterized by enhanced quartz dissolution at inter-grain contacts. The origin of pressure solution and many other related dissolution processes remains elusive. Using an Electrochemical Surface Forces Apparatus we visualized and measured the dissolution of silica glass surfaces close to an electrode surface. The dissolution rates correlate quantitatively with the electrode potential via the Butler–Volmer equation for corrosion. Our experimental results demonstrate that at low temperature, apparent pressure solution and many other mineral dissolution phenomena can be driven by electrochemical processes rather than a pressure-driven process. This finding highlights the role of electrochemical surface potentials in dissolution phenomena at dissimilar material interfaces, and provides new perspectives on pressure solution in particular and a new theoretical basis for predictive control of dissolution phenomena in general.

Smoothing of surface of silica glass by heat treatment in wet atmosphere

The effect of heat treatment on the surface morphology of fused silica glass substrates was investigated. It was found that the water vapor pressure during heat treatment had a strong influence on the flattening of the silica glass surface. The surface of the frosted glass changed into a transparent and lustrous surface after heat treatment with water vapor at 1200 °C for 48 h, whereas surface irregularities remained for heat treatment under a dry atmosphere. It was suggested that the difference in surface flattening was caused by changes in surface viscosity that depended on the concentration of OH groups on the surface. In order to quantitatively understand the effect of the heat treatment atmosphere, power spectral density (PSD) analysis and a novel peak and valley method were applied to the experimental results. From the PSD analysis, it was found that the Mullins’ model could not explain the smoothing behavior by heat treatment. The peak and valley method, which could separate the surface morphology into the surface irregularities and the background undulation, revealed that the Mullins’ model limitation was mainly for the surface and the background undulation could be understood within the model. These results indicate that there are different mechanisms between for the surface smoothing and for the relaxation of the background undulation.

Surface modification of silica glass by CHF 3 plasma treatment and carbon negative-ion implantation for cell pattern adhesion

We have investigated a method for the patterning of cell adhesion on a silica glass by using two-steps of surface modification processes of CHF 3 plasma treatment and negative-ion pattern implantation. For the first step, exposure of CHF 3 plasma to silica glass (SG) was used to obtain hydrophobic surface, leading to eliminate cell-adhesion property. After treatment with RF power of 20 W and exposure time of 120 s, the hydrophobicity was occurred from the increase in contact angle of SG from 43° to 88° and its reason based on XPS analysis was due to formations of C―F, C―F 2, and C―F 3 bonds, so-called fluorocarbonated bonds. Culture of mesenchymal stem cells (MSC) and rat adrenal pheochromocytoma cells (PC12h) showed the degradation of cell adhesion property on the plasma-treated SG surface. For the second step, carbon negative-ion implantation into the hydrophobic fluorocarbonated-SG surface was used to pattern the hydrophilic region, leading to enhance cell adhesion property. The contact angle of C-modified surface decreased to 76° at conditions of 15 keV and 1 × 10 15 ions/cm 2. XPS showed that the hydrophilicity was due to reduction of C―F x bonds and formation of C―O and C═O bonds. After 3 days culture of MSC and PC12h on the C-implanted surface of the plasma-treated SG, a fairly good adhesion patterning of both cells was obtained on the ion-implanted regions.