Life cycle assessment of single-use surgical and embedded filtration layer (EFL) reusable face mask.

BACKGROUND: The outbreak of the COVID-19 pandemic has led to an unprecedented amount of face mask consumption around the world. The increase in face mask consumption has brought focus to their environmental impact. To keep up with the increased demand for face masks, different variations of reusable face masks such as the embedded filtration layer (EFL) reusable face mask have emerged in the market. This study quantifies the environmental impact of the EFL reusable face mask and the single-use surgical face mask. METHODS: The life cycle assessment (LCA) study of the entire value chain from cradle-to-grave is applied to each face mask. Both face masks are evaluated over 1 functional unit (FU) of 31 12-h days for a single person. The ReCiPe method with the Hierachist perspective was applied. A total of nine impact categories as well as the generated waste of each face mask are evaluated. RESULTS: The results show that for 1 functional unit, the use of single-use surgical face mask and EFL reusable face mask will contribute 0.580 kg CO2-eq and 0.338 kg CO2-eq to climate change and generate 0.004 kg and 0.0004 kg of waste respectively. CONCLUSION: Comparing both face masks, the EFL reusable face mask will have a lower emission of at least 30% in terms of the generated waste and the impact categories considered, except for water depletion, freshwater eutrophication, marine eutrophication, and human toxicity.

Evaluation of the ZnO Nanopillar Surface for Disinfection Applications.

Much attention has been devoted to the synthesis and antimicrobial studies of nanopatterned surfaces. However, factors contributing to their potential and eventual application, such as large-scale synthesis, material durability, and biocompatibility, are often neglected in such studies. In this paper, the ZnO nanopillar surface is found to be amenable to synthesis in large forms and stable upon exposure to highly accelerated lifetime tests (HALT) without any detrimental effect on its antimicrobial activity. Additionally, the material is effective against clinically isolated pathogens and biocompatible in vivo. These findings illustrate the broad applicability of ZnO nanopillar surfaces in the common equipment used in health-care and consumer industries.

Iron-based nano-structured surfaces with antimicrobial properties.

Bactericidal nanopillar arrays on cicada wings represent a non-toxic antimicrobial technology as they work through physical cell rupture instead of a chemical mechanism. Here, we reported iron-based nanopillar arrays (FeOOH and Fe2O3) that can grow on various substrates by a simple solution method. These surfaces showed good structure-based antimicrobial activity. Even more simply, we have prepared urchin-type FeOOH and Fe2O3 particles, which can be easily coated onto various substrates to create structure-based disinfection surfaces. This work provides a simple and general methodology to apply this killed-by-structure technology for real world uses.

Elucidating the Role of Interfacial Hydrogen Bonds on Glass Transition Temperature Change in a Poly(Vinyl Alcohol)/SiO2 Polymer-Nanocomposite by Noncovalent Interaction Characterization and Atomistic Molecular Dynamics Simulations.

A thorough experimental investigation of polymer-glass transition temperature (Tg ) is performed on poly(vinyl alcohol) (PVA) and fumed silica nanoparticle (SiNP) composite. This is done together with atomistic molecular dynamics simulations of PVA systems in contact with bare and fully hydroxylated silica. Experimentally, PVA-SiNP composites are prepared by simple solution casting from aqueous solutions followed by its characterization using Fourier-transform infrared spectroscopy (FTIR), dynamic mechanical analysis (DMA), and dynamic scanning calorimetry (DSC). Both theoretical and experimentally deduced Tg are correlated with the presence of hydrogen bonding interactions involving OH functionality present on the surface of SiNP and along PVA polymer backbone. Further deconvolution of FTIR data show that inter-molecular hydrogen bonding present between PVA and SiNP surface is directly responsible for the increase in Tg . SiNP filler and PVA matrix ratio is also optimized for a desired Tg increase. An optimal loading of SiNP exists, in order to yield the maximum Tg increase arising from the competition between hydrogen bonding and crowding effect of SiNP.

Photochromic Materials by Postpolymerisation Surface Modification.

Photochromic materials are available by a postpolymerization surface modification of diverse polymers in a multistep sequential process mediated, first, by carbene insertion chemistry, second, by diazonium coupling with a tethered precursor, and finally by coupling to a spiropyran. This three-step sequence is efficient, and surface loading densities of 1013 molecules cm-2 are typically achievable, leading to materials with observable photochromic and wettability behavior, which operate over multiple cycles without significant photobleaching or loss of efficacy. Materials suitable for application in this process include both reactive, but also lower surface energy polymers. Although the process is particularly efficient for high surface area materials, surface modification onto lower surface area substrates, while being intrinsically less efficient, is nonetheless sufficiently effective that changes in macroscopic photochromic properties are readily observable.

Scope and mechanistic studies of electrophilic alkoxyetherification.

A one-pot electrophilic alkoxyetherification using an olefin, a cyclic ether, a carboxylic acid, and N-bromosuccinimide has been developed. The oxygen nucleophiles, the olefinic substrates, and the cyclic ether partners can be varied to produce a wide range of alkoxyether derivatives.