Surface Modification Of Glass Research Articles

Synthesis of and Glass Surface Modification with Fluorinated Silane Coupling Agents with a Benzene Ring as a Spacer

Fluorinated silane coupling agents with a benzene ring as a spacer, CnF2n + 1-C6H4-SiX3 (n = 4, 6 and 8; X = Cl, OCH3 and NCO), were synthesized and their properties were examined to improve the surface modifying properties of the conventional fluorinated silane coupling agents. The silane coupling agents with a chloro- and methoxy-type hydrolytic groups were synthesized by the reactions of tetrachlorosilane and tetramethoxysilane with the intermediate, Rf-C6H4-MgBr, obtained through the Grignard reaction of the product of the reaction between p-dibromobenzene and perfluoroalkyl iodide in the presence of copper powder. The isocyanato-type silane coupling agents were obtained by allowing the chloro-type coupling agents synthesized to react with silver cyanate. All of the silane coupling agents thus synthesized were colorless transparent liquids. Evaluations were made on the glass surface modified with each of the coupling agents in terms of water contact angle, thermal stability, oxidation resistance, and acid resistance. The coupling agents had the properties similar to those of the conventional fluorinated silane coupling agents with the exception of thermal stability, showing that the newly synthesized agents were thermally stable up to about 300°C.

Practical uses of femtosecond laser micro-materials processing

We describe several approaches to basic femtosecond machining and materials processing that should lead to practical applications. Included are results on high-throughput deep hole drilling in glasses in ambient air, and precision high-speed micron-scale surface modification of composite materials and chalcogenide glasses. Ablation of soda-lime silicate glass and PbO lead-silicate is studied under three different sets of exposure conditions, for which both the wavelength and pulse duration are varied. Ablation rates are measured below and above the air ionization threshold. The differences observed are explained in terms of self-channeling in the ablated hole. Fabrication of practical devices such as waveguides and gratings is demonstrated in chalcogenide glass.

New Strategy for Preparing Thin Gold Films on Modified Glass Surfaces by Electroless Deposition

This paper describes a new strategy for fabricating continuous gold films based on the self-assembly of the gold colloid monolayer on a poly(diallyldimethylammonium chloride)-modified glass slide, followed by electroless plating. Hydroxylamine-mediated reduction was proven as an excellent route to enlargement of immobilized nanoparticles on polymer-coated glass substrates in comparison to formaldehyde-mediated reduction. Au colloidal surface-catalyzed reduction of Au3+ by hydroxylamine exhibited very fast kinetics as monitored and confirmed by UV−vis spectroscopy in real time. The nanoscale morphology of the gold film was dependent on the initial coverage of gold nanoparticles and thermal annealing. Atomic force micrographs further revealed that enlarged particles were neither spherical nor cyclindrical, but highly complex in shape. The gold film thickness and its corresponding surface roughness could be easily controlled by setting the electroless deposition time. X-ray diffraction certified uniformity o...

The influence of surface modifications of glass on glass fiber/polyester interphase properties

Unsized glass fibers and planar glass substrates were subjected to low temperature plasma or wet-chemical process to modify the fiber or substrate surface and thus influence the interphase properties of the glass/polyester system. Plasma-polymerized thin films (interlayers) of organosilicon monomers (hexamethyldisiloxane and vinyltriethoxysilane) were deposited in an RF helical coupling plasma system on the glass surface. Commercial silane coupling agent (vinyltriethoxysilane) was coated onto an unmodified glass surface from an aqueous solution. Bonding at the glass/interlayer interface was analyzed by employing a micro-scratch tester together with an optical polarizing microscope for the planar samples. The results revealed that the adhesion bonding could be controlled by plasma process parameters. Scanning electron and atomic force microscopies enabled characterization of the film surface morphology. Chemical composition and chemical structure of prepared interlayers were characterized using X-ray photoelectron and infrared spectroscopies. Microcomposites (macrocomposites) were tested to evaluate the interfacial shear strength (short-beam strength) of the glass fiber/polyester interphase using the microbond test (short-beam shear). Our study indicated that the most efficient interphase could be prepared by plasma polymerization or wet-chemical process using the vinyltriethoxysilane monomer. The short-beam strength was 110% higher than that for untreated fibers in both cases.

Development of chemically modified glass surfaces for nucleic acid, protein and small molecule microarrays.

Microarrays have become a widely used tool to investigate the living cell at different levels. DNA microarrays enable the expression analysis of thousand of genes simultaneously, while protein arrays investigate the properties and interactions of proteins with other proteins and with non-proteinaceous molecules. One crucial step in producing such microarrays is the permanent immobilization of samples on a solid surface. Our goal was to develop diverse linker systems capable of anchoring different biological samples, especially DNA and drug-like small molecules. We developed 6 different chemical surfaces having a 3-D-like linker system for biomolecule immobilization, and compared them to previously described immobilization strategies. The attachment chemistry utilizes the amino reactive properties of acrylic and epoxy functions. The capacity of the support was increased by creating a branching structure holding the reactive functions. The method of anchoring was investigated through a model reaction. From HPLC and mass spectrometry measurements we concluded that the covalent binding of DNA occurs through nucleobases. The tested systems offer the capability to permanently immobilize several biomolecular species in an array format.

Elastic recoil detection analysis of ion-exchanged soda-lime glass substrates for a-Si:H devices

Elastic recoil detection analysis has been used to study the interaction between soda-lime glass substrates and a-Si:H films. It has been established that H and Na ions penetrate from the near-surface region of the substrate into the deposited film. The results have shown that the influence of the substrate on the properties of a-Si:H can be strongly reduced by glass surface modification using the processes of ion exchange and ion extraction.

Correlation of molecular orientation with adhesion at polystyrene/solid interfaces

Vibrationally resonant sum-frequency generation (VR-SFG) has been used to characterize the molecular orientation of the phenyl groups at the interface between polystyrene (PS) films and surface-modified glass substrates. Both the interface structure and the film adhesion are found to vary as the substrate surface is changed from hydrophobic to hydrophilic. The improved adhesion on the hydrophilic substrate is attributed to the development of attractive hydrogen bonds between surface hydroxyl (OH) groups and the π electron cloud of the phenyl ring. This interaction is manifest by changes in the orientation distribution of the phenyl rings at the interface.

Electrochemical Effects of Surface-Modified Glass Microspheres in Polyvinylpyridine and Polystyrene Sulfonate Composite Electrodes

Tailoring the interfacial region of composite modified electrodes has been a topic of discussion for over a decade. This research examines the electrochemical effects of the formation of unique interfacial regions in surface-modified glass microsphere/polyvinylpyridine composite modified electrodes and surface-modified glass microsphere/polystyrene sulfonate composite modified electrodes. The surfaces of the glass microspheres are modified with different organic functional groups by binding organosilanes to the surfaces of the glass microspheres through a siloxane linkage. This research showed that surface-modified glass microspheres can alter the electrochemical flux through both surface-modified glass microsphere/polyvinylpyridine composites and surface-modified glass microsphere/polystyrene sulfonate composites of hydroquinone, Ru(bpy)32+, and ferricyanide. It was also shown that the polymer itself plays a crucial role in the formation and the properties of the interfacial region. The interfacial region was imaged using fluorescence microscopy, and the microscopy showed that a highly concentrating interfacial region is formed for all of the surface-modified glass microsphere/polymer composites studied regardless of whether there is an electrochemical effect. Further studies with smaller particles are necessary to obtain a large enough interfacial region to be useful for sensor development.

Carbohydrate microarrays for the recognition of cross-reactive molecular markers of microbes and host cells.

We describe here the development of a carbohydrate-based microarray to extend the scope of biomedical research on carbohydrate-mediated molecular recognition and anti-infection responses. We have demonstrated that microbial polysaccharides can be immobilized on a surface-modified glass slide without chemical conjugation. With this procedure, a large repertoire of microbial antigens (approximately 20,000 spots) can be patterned on a single micro-glass slide, reaching the capacity to include most common pathogens. Glycoconjugates of different structural characteristics are shown here to be applicable for microarray fabrication, extending the repertoires of diversity and complexity of carbohydrate microarrays. The printed microarrays can be air-dried and stably stored at room temperature for long periods of time. In addition, the system is highly sensitive, allowing simultaneous detection of a broad spectrum of antibody specificities with as little as a few microliters of serum specimen. Finally, the potential of carbohydrate microarrays is demonstrated by the discovery of previously undescribed cellular markers, Dex-Ids.

Electroless Metallization of Glass Surfaces Functionalized by Silanization and Graft Polymerization of Aniline

Silanization of glass surfaces by (3-glycidoxypropyl)trimethoxysilane (GPS) provided a surface-coupled layer of functional molecules for the subsequent reaction with aniline (An). The so-modified glass surface (the An−GPS−glass surface) was then subjected to oxidative graft polymerization of aniline. The composition and microstructure of the modified glass surfaces were characterized by X-ray photoelectron spectroscopy (XPS), UV−visible absorption spectroscopy, and atomic force microscopy (AFM). The protonation−deprotonation behavior, the interconvertible intrinsic redox states, and the spontaneous metal reduction behavior of the grafted polyaniline (PANI) chains on the glass surface (the PANI−An−GPS−glass surface) were similar to those of the PANI homopolymer. The PANI−An−GPS−glass surface with the electrolessly deposited palladium could be used to catalyze the electroless deposition of copper (the Cu−Pd−PANI−An−GPS−glass surface). The spatial distribution of the grafted PANI chains into the matrix of th...

Surface transformation of bioactive glass in bioreactors simulating microgravity conditions. Part II: numerical simulations.

The effects of simulated microgravity on the surface modification of bioactive glass (BG) in solution were studied using a numerical method. Models were developed for estimating the mass transfers of different chemical species from the surface of bioactive glass particles (microcarriers) suspended in the rotating liquid medium of a NASA-designed high aspect ratio vessel (HARV) bioreactor and on the bottom surface of a static vial. The concentration profiles resulting from chemical reactions and ionic transports were ascertained. Numerical results for the transport under simulated microgravity in the HARV and at normal gravity in the static vial were compared. These results were also compared with those of experiments to verify the enhancement of the reaction kinetics under simulated microgravity conditions. The experimental and numerical studies confirm that simulated microgravity conditions lead to the quick achievement of bioactive glass surface modification.

Electrochemical Studies of Surface-Modified Glass Bead/Nafion Composites

In the past decade, electrochemists have begun modifying electrode surfaces with polymer composites. Each of those composites had advantages over the standard polymer modified electrode. Usually, the major advantage is increased sensitivity. However, years of chromatographic research have proven that tailoring the surface of glass beads can increase the selectivity of a system. The same principle should be applicable to polymer film composites. This research is based upon making glass bead/ion exchange polymer composites with unique interfaces that alter the selectivity of redox species on the basis of physical and chemical characteristics. This is accomplished by modifying the surface of glass beads with organosilanes of varying chain lengths and functional groups. The significance of this research lies in its ability to alter the selectivity of polymer modified electrodes. A surface-modified glass bead/Nafion composite was designed that excludes Ru(bpy)32+ from the film. The surface-modified glass bead/...

Surface modification of chalcogenide glasses by N 2 plasma treatment

Surface modification of chalcogenide glasses by N 2 plasma treatment was investigated in the present paper. Two glasses, Ge 30As 10Se 60 and As 2S 3, were studied and a microwave plasma apparatus equipped with a high-purity nitrogen gas source was used. The effects of N 2 plasma treatment on surface strengthening of chalcogenide glasses were shown by increased microhardness. Explanations are based on a N + implantation effect and bonding of active neutral N atoms from the plasma with sputtered elements from the glass surface. They also account for the much greater effect of N + plasma treatment than that of the N + ions implantation in increasing the microhardness of similar chalcogenide glasses. A comparison of X-ray photoelectron spectrometer (XPS) spectra for the Ge 25As 15Se 60 glass samples before and after N 2 plasma treatment provides further support for the mechanism suggested.

Alteration of glasses by micro-organisms

Micro-organisms are suspected to play a basic part in materials alteration. Obviously, they will be present in nuclear waste repositories, either introduced by technological activity or laid by fluids circulation. Their metabolism may induce chemical modifications to the surrounding media and then affect the durability of storage materials. Biodegradation of glasses is studied in the Pierre Süe Laboratory. In the frame of a collaboration with microbiologists interested in stained glasses alteration, leaching experiments with various species of bacteria and fungi are carried out. Ion beam analysis techniques are performed to quantify surface modification of glasses and elemental incorporation in micro-organisms. Analyses of the solutions will lead to a complete assessment of elemental exchanges between glass sample, culture media and micro-organisms. In this paper, preliminary results on characterisation of glasses and micro-organisms and the first results of leaching experiments are presented.

A factorial analysis of silanization conditions for the immobilization of oligonucleotides on glass surfaces.

The modification of glass surfaces with (3-mercaptopropyl)trimethoxysilane and the application of this to DNA chip technology are described. A range of factors influencing the silanization method, and hence the number of surface-bound, chemically active thiol groups, were investigated using a design of experiment approach based on analysis of variance. The number of thiol groups introduced on glass substrates were measured directly using a specific radiolabel, [14C]cysteamine hydrochloride. For liquid-phase silanization, the number of surface-bound thiol groups was found to be dependent on both postsilanization thermal curing and silanization time and relatively independent of silane concentration, reaction temperature, and sample pretreatment. Depending on the conditions used in liquid-phase silanization, (1.3-9.0) x 10(12) thiol groups/cm2 on the glass samples were bound. The reliability and repeatability of liquid- and vacuum-phase silanization were also investigated. Eighteen-base oligonucleotide probes were covalently attached to the modified surfaces via a 3'-amino modification on the DNA and subsequent reaction with the cross-linking reagent N-(gamma-maleimidobutyryloxy) succinimide ester (GMBS). The resulting probe levels were determined and found to be stoichiometric with that of the introduced thiol groups. These results demonstrate that silanization of glass surfaces under specific conditions, prior to probe attachment, is of great importance in the development of DNA chips that use the simple concept of the covalent attachment of presynthesized oligonucleotides to silicon oxide surfaces.

Surface modification of a silicate glass during XPS experiments

AbstractThe surface chemistry of a commercial soda‐lime silicate glass is shown to change during a long‐duration XPS experiment wherein the glass surface was exposed to the monochromatic x‐rays and low‐energy electrons (0.2–5 eV) that compensate for the charging of the surface. The atomic percentage of sodium increases and that of oxygen decreases with increasing time of the experiment. The separate influence of x‐rays and the low‐energy electrons on the glass surface is also measured. The results show that diffusion of the sodium ions is enhanced more in the presence of x‐rays than in the presence of low‐energy electrons. All observations can be explained well by a model that considers the breaking of the bridging and non‐bridging oxygen bonds, and the trapping of photoelectrons and the externally supplied electrons. Although long‐duration XPS experiments show significant changes on the exposed surface, the chemical composition of the bulk glass obtained during a short experiment agrees well with that obtained from the chemical analysis. Copyright © 2001 John Wiley & Sons, Ltd.

Surface modification of glass by oligomeric fluoroalkylating agents having oxime-blocked isocyanate groups

A new type of oligomeric fluoroalkylating agent with oxime-blocked isocyanate groups was synthesized and the modification of a glass surface using this oligomer was studied. Based on contact angle measurements, the surface free energy of the modified glass was calculated. The results show that the glass surface was effectively fluoroalkylated, the surface free energy was lowered enough and the glass surface became both water- and oil-repellent. The longer the chain length of the fluoroalkyl group (R f) is, the lower is the surface free energy of the modified glass. There existed a good relationship between the surface free energy and the F 1s /Si 2 p peak area ratio measured by XPS. The surface free energies decreased with an increase of this peak area ratio and above a ratio of 2, they became constant. The effects of modification by fluoroalkyl end-capped oligomers having oxime-blocked isocyanate groups and fluoroalkyl end-capped silanes were interpreted in terms of the structure of the modified layer, i.e. in terms of the monolayer interphase and network interphase models, respectively.

FAST slides: a novel surface for microarrays.

We have evaluated FAST slides, a glass slide with a microporous polymeric surface that is a suitable substrate for microarray technology. The surface is a nitrocellulose-based polymer that binds DNA and proteins in a noncovalent but irreversible manner. FAST slides are compatible with robotic systems currently used to create microarrays and can easily accommodate volumes of 0.03-2 nL/spot. Our data indicate that FAST slides have a much higher binding capacity for DNA and better spot-to-spot consistency than traditional poly-lysine-coated slides. In addition, FAST slides are well suited for fluorescent detection because of their relatively low light scatter and efficient retention of arrayed DNA. These properties translate into fluorescent sensitivity comparable to modified glass surfaces. FAST slides are also ideal for arraying proteins, making them the only substrate of their kind currently available for microarray applications.

Light-driven motion of liquids on a photoresponsive surface

The macroscopic motion of liquids on a flat solid surface was manipulated reversibly by photoirradiation of a photoisomerizable monolayer covering the surface. When a liquid droplet several millimeters in diameter was placed on a substrate surface modified with a calix[4]resorcinarene derivative having photochromic azobenzene units, asymmetrical photoirradiation caused a gradient in surface free energy due to the photoisomerization of surface azobenzenes, leading to the directional motion of the droplet. The direction and velocity of the motion were tunable by varying the direction and steepness of the gradient in light intensity. The light-driven motion of a fluid substance in a surface-modified glass tube suggests potential applicability to microscale chemical process systems.

Surface reactions of a plasma-sprayed CaO–P 2O 5–SiO 2-based glass with albumin, fibroblasts and granulocytes studied by XPS, fluorescence and chemiluminescence

X-ray photoelectron spectroscopy (XPS) was used to define the chemical composition of the outermost surface layer and the surface modification of a plasma-coated phospho-silicate glass (identified as BVA) when immersed in K-phosphate buffer or in phosphate buffered human albumin solution. Its behavior was compared with that of a soda-lime-based glass (identified as BVH) treated in the same way. The surface % composition of plasma-sprayed glass was consistent with bulk composition. After incubation with buffer, a Ca–P-rich layer developed only on the surface of BVA glass. Human serum albumin was bound reversibly to both glasses maintaining its native state. However, the protein completely covered the BVA glass surface within 24 h, with the formation of a mixed albumin–Ca–P layer, while 4 days incubation was necessary for complete coverage of BVH glass surface. Murine fibroblasts seeded on plasma-coated BVA glass showed a proliferation pattern similar to that of control cells grown on Petri dish, while cells seeded on BVH had more restricted growth. A limited response was induced in polymorphonuclear granulocytes by both bulk glasses powder. In conclusion, the glass identified as BVA has the suitable characteristics of its surface layers to be considered biologically active from both a chemical and a cellular point of view.