Ultralow Dispersion Multicomponent Thin-Film Chalcogenide Glass for Broadband Gradient-Index Optics.

A novel photothermal process to spatially modulate the concentration of sub-wavelength, high-index nanocrystals in a multicomponent Ge-As-Pb-Se chalcogenide glass thin film resulting in an optically functional infrared grating is demonstrated. The process results in the formation of an optical nanocomposite possessing ultralow dispersion over unprecedented bandwidth. The spatially tailored index and dispersion modification enables creation of arbitrary refractive index gradients. Sub-bandgap laser exposure generates a Pb-rich amorphous phase transforming on heat treatment to high-index crystal phases. Spatially varying nanocrystal density is controlled by laser dose and is correlated to index change, yielding local index modification to ≈+0.1 in the mid-infrared.

Performance Stability of Silicone Oxide-Coated Plastic Parenteral Vials.

A new packaging system was developed for parenteral pharmaceuticals that combines the best attributes of plastic and glass without their respective drawbacks. This technological advancement is based on the synergy between high-precision injection-molded plastics and plasma coating technology. The result is a shatter-resistant, optically clear, low-particulate, and chemically durable packaging system. The demand for this product is driven by the expanding market, regulatory constraints, and product recalls for injectable drugs and biologics packaged in traditional glass materials. It is shown that this new packaging system meets or exceeds the important performance characteristics of glass, especially in eliminating the glass delamination and breakage that has been observed in many products. The new packaging system is an engineered, multilayer, glass-coated plastic composite that provides a chemically stable contact surface and oxygen barrier performance that exceeds a 2 year shelf life requirement. Evaluation of the coating system characteristics and performance stability to chemical, temperature, and mechanical extremes are reported herein.LAY ABSTRACT: A new packaging system for parenteral pharmaceuticals was developed that combines the best attributes of plastic and glass without their respective drawbacks. This technological advancement is based on the synergy between high-precision injection-molded plastics and plasma coating technology. The result is a shatter-resistant, optically clear, low-particulate, and chemically durable packaging system. It is shown that this new packaging system meets or exceeds the important performance characteristics of glass, especially in eliminating the glass delamination and breakage that has been observed in many products. The new packaging system is an engineered, multilayer, glass-coated plastic composite that provides a chemically stable contact surface and oxygen barrier performance that exceeds a 2 year shelf life requirement. Evaluation of the coating system characteristics and performance stability to chemical, temperature, and mechanical extremes are reported herein.

Vibrational Sum Frequency Generation Spectroscopy Study of Hydrous Species in Soda Lime Silica Float Glass.

It is generally accepted that the mechanical properties of soda lime silica (SLS) glass can be affected by the interaction between sodium ions and hydrous species (silanol groups and water molecules) in its surface region. While the amount of these hydrous species can be estimated from hydrogen profiles and infrared spectroscopy, their chemical environment in the glass network is still not well understood. This work employed vibrational sum frequency generation (SFG) spectroscopy to investigate the chemical environment of hydrous species in the surface region of SLS float glass. SLS float glass shows sharp peaks in the OH stretching vibration region in SFG spectra, while the OH stretch peaks of glasses that do not have leachable sodium ions and the OH peaks of water molecules in condensed phases are normally broad due to fast hydrogen bonding dynamics. The hydrous species responsible for the sharp SFG peaks for the SLS float glass were found to be thermodynamically more stable than physisorbed water molecules, did not exchange with D2O, and were associated with the sodium concentration gradient in the dealkalized subsurface region. These results suggested that the hydrous species reside in static solvation shells defined by the silicate network with relatively slow hydrogen bonding dynamics, compared to physisorbed water layers on top of the glass surface. A putative radial distribution of the hydrous species within the SLS glass network was estimated based on the OH SFG spectral features, which could be compared with theoretical distributions calculated from computational simulations.

Adsorption reactions of carboxylic acid functional groups on sodium aluminoborosilicate glass fiber surfaces.

Multicomponent silicate glasses are ubiquitous in modern society as evidenced by their inclusion in applications ranging from building materials and microelectronics to biomedical implants. Of particular interest in this study is the interface between multicomponent silicate glasses and adhesive polymers. These polymeric systems often possess a variety of different organic functional groups. In this study, we selected acetic acid as a probe molecule representative of the carboxylic acid functional group found in many adhesives. We have used Fourier transform infrared spectroscopy (FT-IR) and NMR to study the interaction of acetic acid with the surface of sodium aluminoborosilicate continuous glass fibers. Methods were developed that enable analyses to be carried out without damaging or altering the pristine as drawn fiber surface. While dosing the surface of fumed silica with acetic acid resulted in the formation of silyl ester groups, analogous dosing of sodium aluminoborosilicate glass fibers resulted in the formation of carboxylate species, principally coordinated to sodium, while silyl ester groups were not observed.

Mass fabrication technique for polymeric replicas of arrays of insect corneas.

Motivated to develop a technique for producing many high-fidelity replicas for the sacrifice of a single biotemplate, we combined a modified version of the conformal-evaporated-film-by-rotation technique and electroforming to produce a master negative made of nickel from a composite biotemplate comprising several corneas of common blowflies. This master negative can function as either a mold for casting multiple replicas or a die for stamping multiple replicas. An approximately 250 nm thick nickel film was thermally deposited on an array of blowfly corneas to capture the surface features with high fidelity and then a roughly 60 microm thick structural layer of nickel was electroformed onto the thin layer to give it the structural integrity needed for casting or stamping. The master negative concurrently captured the spatial features of the biotemplate at length scales ranging from 200 nm to a few millimeters. Polymer replicas produced thereafter by casting did faithfully reproduce features of a few micrometers and larger in dimension.

Fabrication of free-standing replicas of fragile, laminar, chitinous biotemplates.

The conformal-evaporated-film-by-rotation technique, followed by the dissolution of chitin in an aqueous solution of orthophosphoric acid, can be used to fabricate free-standing replicas of fragile, laminar, chitinous biotemplates. This novel approach was demonstrated using butterfly wings as biotemplates and GeSeSb chalcogenide glass for replicas.

Processing and characterization of ultrathin carbon coatings on glass.

Ultrathin carbon layers, on the order of 3-6 nm in thickness, were formed on glass substrates by spin coating and pyrolysis of polymer precursors. The organic precursors used were poly(furfuryl alcohol), coal tar pitch, and a photoresist. The carbon coatings were characterized by ellipsometry, optical profilometry, water contact angle, confocal Raman spectroscopy, UV-vis spectroscopy, and atomic force microscopy. We also report the transparency, hydrophobicity, friction, weathering resistance, and electrical conductivity of the carbon-coated glass. The results reveal that up to 97% transparent, ultrathin carbon films could be formed on glass substrates with a root-mean-square roughness of less than approximately 0.3 nm. This carbon layer modified the otherwise hydrophilic surface of the glass to yield a water contact angle of 85 degrees . The coatings were also found to provide a water barrier against weathering under hot and humid conditions. A 4.5-nm-thick carbon film on glass had a sheet resistance of 55.6 kOmega m and a conductivity of 40 S/cm.

19F MAS NMR quantification of accessible hydroxyl sites on fiberglass surfaces.

Solid-state 19F nuclear magnetic resonance (NMR) spectroscopy is used for the quantitative investigation of accessible hydroxyl sites on low surface area glass fibers. Samples with surface areas as low as 0.2 m2/g are investigated through covalent binding of (3,3,3-trifluoropropyl)dimethylchlorosilane. 19F is an ideal nucleus for solid-state NMR, as it has a nuclear spin of 1/2 and a natural isotopic abundance of 100%. High-speed MAS techniques (with rotor spinning frequencies greater than 15 kHz) sufficiently average the CSA and any strong dipolar couplings to allow for superior resolution, especially from terminal -CF3 groups. Studies of two model silica gels with higher surface area, but different pore sizes, provide chemical shift and spin-lattice relaxation rate parameters for probe molecules bound within different environments: pores approaching the size of the probe molecule and pores much larger than the molecular size where intermolecular interactions are assumed to be at a minimum. Resonances assignable to both types of binding environments are found in the spectra of similarly functionalized low surface area fibers. Accessible hydroxyl coverages in the range of 0.8-1.3 OH/nm2 have been measured, and an initial discussion of fiber surface roughness and microporosity is advanced.