Digital Library

Given the transmittance spectrum of a process witness sample, the procedures and rational of deriving the index of refraction values versus wavelength from this spectrum are demonstrated by example. The various index of refraction models, algorithms, and functions are described. Some of the functions are only mathematical equations for fitting to the spectral data, and others have a physical basis in nature.

https://doi.org/10.14332/svc23.proc.0039

Biopolymers are very promising materials that find use in several industrial applications, ranging from packaging and food industry to the pharmaceutical and biomedical fields. Their main advantages include biocompatibility, biodegradability, non-toxicity and renewability. Despite all their great benefits, biopolymer foils also exhibit a few drawbacks that limit their application, such as poor barrier properties. To overcome these restraints, thin-layer coatings can be applied. In this work, the possibility of coating biopolymer foils using a commercially available bipolar pulsed DC plasma assisted chemical vapor deposition (PACVD) system was studied. This technique turns out to be cheap and relatively easy to scale up. Starch-, polylactic acid- and cellulose-based foils were used as substrates. Silicon- and carbon-based coatings were deposited, using hexamethyldisiloxane and acetylene as precursors. The effect of coating thickness (5- and 15-minutes deposition time) on the barrier properties was examined. ATR-FTIR spectroscopy of the generated films showed the typical siloxane absorption bands for the silicon-based films. Coating thicknesses were between 50 and 150 nm. Surface free energy was in the range 41-48 mN/m for C- and 19-28 mN/m for Si-coatings. Water vapor transmission rates were substantially reduced for cellulose-based films (up to 65%), but not for PLA or starch. A reduction of over 95% in oxygen transmission rate was measured for regenerated cellulose. This study highlights the opportunity to use bipolar pulsed DC PACVD as an alternative for coating polymeric materials, with the appropriate adjustments.

https://doi.org/10.14332/svc23.proc.0044

Thin-film nonuniformity is a fundamental, systematic error present in optical coating systems which leads to limitations on substrate sizes, reductions in capacity, poorer production yield, and other associated issues. Fundamental system design principles, based on source distribution and substrate mounting/motion profiles, can provide significant control over thin-film uniformity. Such an approach greatly improves the overall deposition performance, enabling deposition systems to provide both uniform and prescribed non-uniform film thickness profiles very accurately.

https://doi.org/10.14332/svc23.proc.0034

Designing with varying indices of refraction versus thickness in very thin optical films was delt with in earlier papers by interpolating the magnitude of the indices for new thicknesses of that material between indices which have been measured for given thicknesses. This has generally proved successful for most applications but could prove problematic in the case of resonant peaks which shift in wavelength with layer thickness. This paper reports a solution to this problem by interpolating in not only the magnitude of the indices but also with the shifting wavelength. This should make it practical to deal with resonant plasmonic phenomena and quantum dot behavior. The possibilities and limitations of this interpolation approach are discussed.

https://doi.org/10.14332/svc23.proc.0038

Ultrathin films are building blocks for many technical, biomedical, and microelectronic devices. Determining their microstructure and properties is essential for device design based on these films. Atomic Layer Deposition (ALD) is a high-quality thin film deposition process having exceptional conformality even on the rough and non-uniform surfaces because of its self-limiting ability at the subatomic level. In this study, we have deposit Cu based oxide coatings using Plasma Enhanced Atomic Layer Deposition (PEALD) and Ozone Atomic Layer Deposition (O3ALD) techniques on silicon and platinum nanoarchitected substrates for biomedical applications. Ellipsometry is used to determine the film thickness and also the optical properties of the films. Furthermore, the properties of the films are characterized using nanoindentation, Focused Ion Beam (FIB), X-ray diffraction (XRD), X-ray photoelectron microscope (XPS), Energy Dispersive X-ray Spectroscopy (EDS), and Scanning Electron Microscope (SEM). The coating is ultraconformal on nanoarchitected platinum substrates. The biomedical properties of ALD CuO coatings are also studied. This work will be insightful for designing various reliable biomedical devices.

https://doi.org/10.14332/svc23.proc.0009

Conductive electrical contacts are key elements of low-cost/high-throughput flexible electronic devices. Traditional patterning of metal films with masking or lithography presents limitations to feature geometry, manufacturing development, and/or scalability. Laser patterning of electrical contacts via ablation for subtractive manufacturing is one attractive option. The laser can scan the surface at rates of 8000 mm/s for high production rates. Adjustments to device architecture or geometry for optimal performance may be actualized immediately by alteration of the laser scanning pattern and with no material or time cost as with mask fabrication. Integration of flexible, two-dimensional (2D) semiconducting materials on laser patterned substrates requires surface roughness below 1 nm for application of continuous films. Optimized laser process variables for rapid patterning of electrical contacts for 2D electronic devices were identified by programming a patterning laser to produce a grid of ablated metal zones on a flexible glass substrate employing hundreds of laser power and scan rate conditions. A study is shown to highlight the role of surface morphology on the continuity and adhesion of successive sputtered 2D thin film layers. An example application of rapid and low-cost laser fabrication of 2D electronic biosensor devices is used to demonstrate additional functionality of laser patterning such as tuning surface roughness to control fluid flow on the sensor surface. Scaled production of these devices is aided by laser patterned thin film crystallization. Sensor response data is shown comparing thermal and laser activated crystallization of thin film MoS₂. Integration of roll-to-roll technology and in situ quality control via high throughput Raman spectroscopy promise high yield, low-cost production of devices whose performance meets requirements for analysis of biological samples.

https://doi.org/10.14332/svc23.proc.0010

Hospital Associated Infections (HAI) are the most common complication of hospital care and one of the top 10 leading causes of death in the USA as reported by The Agency for Healthcare Research and Quality. The most common pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp), commonly known as the ESKAPE pathogens, are the leading causes of HAIs. Contracting a HAI can often lead to increased morbidity and can have a devastating effect on physical, mental, and financial health. In addition to this, HAIs cost the healthcare system billions of dollars a year in added expenditure. Recent research suggests that a growing number of HAIs are caused by pathogens that have become resistant to the antimicrobial medications typically used to control them. The US Center for Disease Control and Prevention identifies that nearly 1.7 million hospitalized patients annually acquire HAIs while being treated for other health issues, and that more than 98,000 patients (1 in 17) die due to these.

This paper presents a protective nano-structured coating with the capability to rapidly kill microbes and pathogens, resulting in a self-sanitizing surface which can be applied to high contact areas throughout hospital and healthcare settings. The patentend iC-nanoTM, Infection Control via Nanotechnology, material can be applied to both 2D and 3D surfaces. This work focuses on the technology when applied to observation machines in patient rooms, out-patient check-in kiosks, push plates leading onto various wards and lever door handles throughout the Royal Liverpool University Hospital in the United Kingdom.

For the application on screens, the transparent coating is deposited on flexible polyethylene terephthalate substrates produced in an in-line industrial system. The coating technology could easily be scaled up to a roll-to-roll (R2R) production, to result in a larger throughput of material for commercial use. A large batch coater at Gencoa produced the coatings on the push plates, pull handles and lever door handles. A number of biochemical and biological tests are performed in order to qualify and quantify the antimicrobial efficacy.

https://doi.org/10.14332/svc23.proc.0011

Periprosthetic joint infections (PJI) caused by bacteria are one of the primary failure causes in orthopedics, which results in not only cumbersome revision operations and expensive medical costs, but also severe complications leading to amputation or even death of the patient. To prevent, an active-antibacterial technique to reduce bacterial infections has been proposed in a parallel study to demonstrate the feasibility of using high power impulse magnetron sputtering (HiPIMS) to obtain a very thin antibacterial silver coating onto a titanium substrate, with its film adhesion, cytotoxicity as well as silver ion release investigated in detail. However, in practical clinical use, preoperative sterilization is essential to ensure the asepsis condition of the implant; hence various sterilization processes are worth noting for possible damage to the HiPIMS-Ag film. In this study, steam sterilization, ethylene oxide (EO) sterilization, and hydrogen peroxide (H₂O₂) plasma sterilization are carried out to understand the durability of HiPIMS-Ag film. The experimental results show that strong adhesion of HiPIMS-Ag film still remain, even subjecting to harsh sterilization processes. Regardless of the sterilization processes, the treated HIPIMS-Ag titanium samples can maintain the index of antibacterial activity value (R) over 2.0 against Staphylococcus aureus and Escherichia coli, whilst maintaining excellent osteoblast compatibility. The change in the chemical state of the treated HiPIMS-Ag film under different sterilization processes was discussed. These results suggest that HIPIMS-Ag is capable of resisting a series of sterilization processes to guarantee its characteristics, making it ready for active-antibacterial treatment in clinical orthopedic implant application.
https://doi.org/10.14332/svc23.proc.0008

Biomedical coatings, such as titanium nitride (TiN), can be enhanced to have an antimicrobial function by adding bactericidal elements such as silver, copper, or zinc. The columnar microstructure of TiN results in high surface area fractal coatings with excellent charge exchange. Material properties such as thickness, composition, and microstructure can significantly impact the electrochemical performance and durability. One way to explore this large parameter space is by combining combinatorial synthesis methods with various scanning techniques. Combinatorial thin films of TiN alloy neurostimulation electrode coatings were deposited via reactive magnetron sputtering, resulting in large compositional spaces for investigation. Scanning electrochemical techniques were developed to expedite the measurement of coatings for electrochemical performance and durability as a function of thickness, composition, and structure. Electrochemical properties were measured with cyclic voltammetry, chronoamperometry, electrochemical impedance spectroscopy, and electrolyte analysis. Material properties were investigated with scanning electron microscopy, energy dispersive spectroscopy, x-ray diffraction, and atomic force microscopy. These techniques were used to connect the material properties to the electrochemical performance.

https://doi.org/10.14332/svc23.proc.0007

Successful digitalization of deposition process requires real-time data from a variety of sensors. All data must be collected and saved in a single data base to allow common processing, evaluation and visualization. Especially in-situ data are often rather extensive and complex such as spectral data from spectroscopic plasma monitoring or mass spectroscopy or frequency spectra from electrical probes. Data transfer time as well as data base space usually limit the amount of data which can be transferred from the sensor to the data base in 24/7 production environments. These limits together with proprietary data formats are among the current fundamental barriers to the digitalization of production processes.

Smart and automated in-situ sensors are one solution to overcome these obstacles as they are able to preprocess the large amount of acquired data according to configurable algorithms and evaluation rules in real-time. This results in manageable in-situ parameters which should reflect all main and important properties of the in-situ process data and which allows the transfer to and storage in the data base in accordance with the data from all other sensors.

In this talk, the idea of a smart sensor is demonstrated at a pulsed plasma process application using the in-situ spectroscopic plasma monitoring technique in combination with realtime acquisition of the electrical pulse curves of voltage and current. Real-time evaluation reduces the amount of data considerably without losing the relevant process information.

Examples of HIPIMS applications in production like environments of continuous 24/7 operation are presented and discussed.

https://doi.org/10.14332/svc23.proc.0013