Some physical properties of multilayered films

Schrenk, W. J.; Alfrey, Turner

doi:10.1002/pen.760090604

Cited by 95 publications

(35 citation statements)

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“…The barrier effect is higher for a-C:H:Si than for the SiO x and a:C:H:Ti films, whereby the level of permeation is comparable to published data of sputtered oxide coatings of similar thickness [61]. Gas permeation can be theoretically described based on the equation (2) in which h is the thickness and P the permeability of the film (c), substrate (s) and the whole system [62]. Generally, permeation in thin film materials is defect controlled, while the intrinsic permeation rates of the material has inferior contribution.…”

Section: Gas Permeation Behaviorsupporting

confidence: 74%

Gas Permeation, Mechanical Behavior and Cytocompatibility of Ultrathin Pure and Doped Diamond-Like Carbon and Silicon Oxide Films

et al. 2013

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Protective ultra-thin barrier films gather increasing economic interest for controlling permeation and diffusion from the biological surrounding in implanted sensor and electronic devices in future medicine. Thus, the aim of this work was a benchmarking OPEN ACCESSCoatings 2013, 3 269 of the mechanical oxygen permeation barrier, cytocompatibility, and microbiological properties of inorganic ~25 nm thin films, deposited by vacuum deposition techniques on 50 µm thin polyetheretherketone (PEEK) foils. Plasma-activated chemical vapor deposition (direct deposition from an ion source) was applied to deposit pure and nitrogen doped diamond-like carbon films, while physical vapor deposition (magnetron sputtering in pulsed DC mode) was used for the formation of silicon as well as titanium doped diamond-like carbon films. Silicon oxide films were deposited by radio frequency magnetron sputtering. The results indicate a strong influence of nanoporosity on the oxygen transmission rate for all coating types, while the low content of microporosity (particulates, etc.) is shown to be of lesser importance. Due to the low thickness of the foil substrates, being easily bent, the toughness as a measure of tendency to film fracture together with the elasticity index of the thin films influence the oxygen barrier. All investigated coatings are non-pyrogenic, cause no cytotoxic effects and do not influence bacterial growth.

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Section: Gas Permeation Behaviorsupporting

confidence: 74%

Gas Permeation, Mechanical Behavior and Cytocompatibility of Ultrathin Pure and Doped Diamond-Like Carbon and Silicon Oxide Films

et al. 2013

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“…As shown in Figure 10, this creates a bilayer that is "multiplied" to achieve a many-layered product. The multiplication method is simple, and was patented by Dow Chemical in 1969 (10). In the 1990's the technology was licensed to the 3M Company, primarily finding use as reflective materials in light pipes.…”

Section: Progress If7 Mu/ti/ayer Coextrusionmentioning

confidence: 99%

Characterization of ermally Stable Dye-Doped Polyimide

2016

Dyes and Drugs

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The synthesis of a photoswitchable polymer by grafting an azobenzene dye to methacrylate followed by polymerization is presented. The azobenzene dye undergoes a trans-cis photoisomerization that causes a persistent change in the refractive index of cast polymer films. This novel polymer was incorporated into superlattices prepared by spin casting and the optical activity of the polymer was maintained. A modified coextruder that allows the rapid production of soft matter superlattices was designed and fabricated.

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“…Their approach produced GRIN lenses from films that consisted of thousands of nanolayers of two different polymers having two different refractive indices . The key technology used to fabricate such films is a microlayer polymer coextrusion process, which appeared in the literature as early as 1969 (Alfrey, Gurnee, and Schrenk 1969;Schrenk and Alfrey 1969). This polymer processing technology was developed further at CWRU, and the application to the fabrication of GRIN lenses was patented ).…”

Section: B Grin Lens Fabrication Research In the Darpa Boss Programmentioning

confidence: 99%

Gradient Index Optics at DARPA

Teichman¹,

Holzer²,

Balko³

et al. 2013

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Executive SummaryThe Defense Advanced Research Projects Agency (DARPA) asked the Institute for Defense Analyses (IDA) to assemble a summary of work on gradient index optics completed under funding from the Agency. The purpose was to archive the efforts, motivation, and accomplishments that the Agency supported and to provide a reference for any future programs that explore this new area of optics.Although optical instruments, such as lenses and mirrors, dating back thousands of years ago have been unearthed, lenses were not put into practical use until the invention of eyeglasses in the thirteenth century. The microscope and the telescope were invented in the seventeenth century, but no revolutionary changes occurred in these complex lens systems for the next 200 years. Most lens systems remained homogeneous multi-element systems with spherical glass surfaces and fixed optical properties. Recently, however, new materials and lens designs have been developed, inspired by properties of biological eyes. Materials with a gradient index (GRIN) allow the development of compact systems that have high focusing power while correcting for aberration.In 2002, DARPA initiated the Bio-Optic Synthetic Systems (BOSS) program, which aimed to synthesize the components of a biologically inspired vision system and demonstrate a level of performance beyond that of standard optical imaging systems (i.e., with reduced size and complexity). Out of more than a dozen exploratory efforts, four efforts were selected for further development and demonstration: fluidic adaptive zoom lenses, foveated imaging, photon sieves, and nanolayer lenses.As an example, Case Western Reserve University (CWRU) and the Naval Research Laboratory (NRL) collaborated on the nanolayer lens effort to create a synthetic lens that would mimic the structure and capabilities of an octopus eye. The CWRU/NRL team used a forced assembly nanolayer coextrusion process to form films that had a tailored refractive index consisting of thousands of nanolayers of two different polymers that had different refractive indices. The films of various n were stacked to create a refractive index range (Δn) and formed into hemispheres, which were combined to form the synthetic bi-convex octopus lens. A zoom lens system constructed from three of these GRIN lenses was demonstrated on a small unmanned aerial vehicle (UAV).Limited manufacturing capabilities have hindered practical applications of GRIN lenses. In 2008, DARPA initiated the Manufacturable Gradient Index Optics (M-GRIN) program to address GRIN lens manufacturing issues in the development of low-cost, iii customizable GRIN-based optics for use in a variety of military systems. This effort included a significant focus on metrology, where new tools were required for monitoring the polymer nanolayer process for GRIN optics. Performers in the M-GRIN program included the following teams:

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Some physical properties of multilayered films

Cited by 95 publications

References 1 publication

Gas Permeation, Mechanical Behavior and Cytocompatibility of Ultrathin Pure and Doped Diamond-Like Carbon and Silicon Oxide Films

Gas Permeation, Mechanical Behavior and Cytocompatibility of Ultrathin Pure and Doped Diamond-Like Carbon and Silicon Oxide Films

Characterization of ermally Stable Dye-Doped Polyimide

Gradient Index Optics at DARPA

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