Ultraviolet–ozone surface cleaning of injection‐molded, thermoplastic microcantilevers

Urwyler, Prabitha; Pascual, Alfons; Müller, Bert; Schift, Helmut

doi:10.1002/app.41922

Cited by 4 publications

(2 citation statements)

References 24 publications

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“…Additionally, the oxidation (more precisely, oxygen uptake) of the ZnO film in the UVO process can be explained. Once compressed air is supplied into the chamber of the used UVO cleaner, atomic oxygen is dissociated by 185 nm UV radiation, and, afterwards, ozone is continuously produced by 254 nm radiation [83,84,85,86,87,88], as follows:O 2 + hv(185 nm) → O(3p) + O(3p), O(3p) + O 2 + O 2 → O 3 + O 2, O 3 + hv(254 nm) → O(1d) + O 2. …”

Section: Resultsmentioning

confidence: 99%

Effect of Ultraviolet–Ozone Treatment on the Properties and Antibacterial Activity of Zinc Oxide Sol-Gel Film

Kim

Lee

et al. 2019

Materials

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To combat infectious diseases, zinc oxide (ZnO) has been identified as an effective antibacterial agent; however, its performance can be adversely affected by harsh application environments. The ozone impact on ZnO antibacterial film needs to be evaluated prior to its application in an ozone disinfection system. In this study, ZnO films synthesized via sol-gel/spin-coating were subjected to ultraviolet–ozone (UVO) treatment for different periods. Surface investigations using scanning electron microscopy, ultraviolet–visible spectroscopy, and X-ray photoelectron spectroscopy revealed that the treatment-induced film changes. With longer UVO treatment, the surface porosity of the film gradually increased from 5% to 30%, causing the transmittance reduction and absorbance increase in visible-light range. Phase transformation of Zn(OH)2 to ZnO occurred during the first 10 min of UVO treatment, followed by oxygen uptake as a consequence of the reaction with reactive oxygen species generated during UVO treatment. However, despite these surface changes, the satisfactory antibacterial activity of the synthesized ZnO film against Staphylococcus aureus and Escherichia coli was sustained even after 120 min of UVO treatment. This indicates that the UVO-induced surface changes do not have a significant effect on the antibacterial performance and that the ZnO sol-gel film possesses good functional durability in ozone environments.

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Section: Resultsmentioning

confidence: 99%

Effect of Ultraviolet–Ozone Treatment on the Properties and Antibacterial Activity of Zinc Oxide Sol-Gel Film

Kim

Lee

et al. 2019

Materials

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“…Polycarbonate was chosen as it is known to show evidence of a reaction after only ten seconds at room temperature with ozone and UV. [7][8][9][10] In FFF, the thermoplastic layer cools rapidly after being deposited onto the part. This leaves only 2-5 seconds where the temperature is above the glass transition temperature, where reaction kinetics are more favorable.…”

Section: Introductionmentioning

confidence: 99%

Fused Filament Fabrication of Polycarbonate in a Reactive Atmosphere

2022

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Fused Filament Fabrication (FFF) has become extremely useful in various industries, particularly when complex parts are needed in low volumes.However, the material properties available in FFF polymers are limited in scope.The properties of a FFF part can be changed in multiple ways. This study explores changing the bulk properties of a part by affecting each layer as it prints. Prior work has demonstrated the feasibility of altering polymer properties by layerwise exposure to a liquid chemical, but properties have never been modified in situ using a reactive gas. Here, FFF is done in the presence of a reactive gas. Specifically, the part is printed with polycarbonate in a reactive atmosphere of ozone and ultra-violet light. It was found that as each layer is exposed to a reactive gas, the bulk properties of the part change. A visual chemical change was seen, as well as confirmation of the reaction through Fourier transform infrared spectroscopy attenuated total reflectance. The change in mechanical properties was measured through Dynamic Mechanical Analysis shear tests, showing a bulk change can be efficiently produced through FFF in a reactive atmosphere.

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An update on coating/manufacturing techniques of microneedles

Tarbox

Watts

Cui

et al. 2017

Drug Deliv. and Transl. Res.

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Recently, results have been published for the first successful phase I human clinical trial investigating the use of dissolving polymeric microneedles… Even so, further clinical development represents an important hurdle that remains in the translation of microneedle technology to approved products. Specifically, the potential for accumulation of polymer within the skin upon repeated application of dissolving and coated microneedles, combined with a lack of safety data in humans, predicates a need for further clinical investigation. Polymers are an important consideration for microneedle technology-from both manufacturing and drug delivery perspectives. The use of polymers enables a tunable delivery strategy, but the scalability of conventional manufacturing techniques could arguably benefit from further optimization. Micromolding has been suggested in the literature as a commercially viable means to mass production of both dissolving and swellable microneedles. However, the reliance on master molds, which are commonly manufactured using resource intensive microelectronics industry-derived processes, imparts notable material and design limitations. Further, the inherently multi-step filling and handling processes associated with micromolding are typically batch processes, which can be challenging to scale up. Similarly, conventional microneedle coating processes often follow step-wise batch processing. Recent developments in microneedle coating and manufacturing techniques are highlighted, including micromilling, atomized spraying, inkjet printing, drawing lithography, droplet-born air blowing, electro-drawing, continuous liquid interface production, 3D printing, and polyelectrolyte multilayer coating. This review provides an analysis of papers reporting on potentially scalable production techniques for the coating and manufacturing of microneedles.

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Ultraviolet–ozone surface cleaning of injection‐molded, thermoplastic microcantilevers

Cited by 4 publications

References 24 publications

Effect of Ultraviolet–Ozone Treatment on the Properties and Antibacterial Activity of Zinc Oxide Sol-Gel Film

Effect of Ultraviolet–Ozone Treatment on the Properties and Antibacterial Activity of Zinc Oxide Sol-Gel Film

Fused Filament Fabrication of Polycarbonate in a Reactive Atmosphere

An update on coating/manufacturing techniques of microneedles

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