We fabricated thermoplastic surfaces possessing extremely limited water and oil wettability without employment of long-chain perfluoroalkyl (LCPFA) substances. Namely, by taking advantage of the structure and behavior of original oleophobic perfluoropolyether (PFPE) methacrylate (PFM) molecular bottlebrush (MBB) additive we obtained polymeric surfaces with oil contact angles well above 80° and surface energy on the level of 10 mN/m. Those angles and surface energies are the highest and the lowest respective values reported to date for any bulk solid flat organic surface not containing LCPFA. We show experimentally and computationally that this remarkable oil repellency is attributed to migration of small quantities of the oleophobic MBB additives to the surface of the thermoplastics. Severe mismatch in the affinity between the densely grafted long side chains of MBB and a host matrix promotes stretching and densification of mobile side chains delivering the lowest surface energy functionalities (CF3) to the materials’ boundary. Our studies demonstrate that PFM can be utilized as an effective low surface energy additive to conventional thermoplastic polymers, such as poly­(methyl methacrylate) and Nylon-6. We show that films containing PFM achieve the level of oil repellency significantly higher than that of polytetrafluoroethylene (PTFE), a fully perfluorinated thermoplastic. The surface energy of the films is also significantly lower than that of PTFE, even at low concentrations of PFM additives.

High concentration of carbon monoxide (CO) in the gas mixture entering the fuel cell can cause fuel cell poisoning, which can significantly reduce the life expectancy of the cell. To overcome this problem, we propose a new methodology based on the use of micro-cantilevers to detect minute concentrations of CO in a gas mixture. For this purpose, micro-cantilevers are coated with Copper Y (CuY) zeolite and utilized to selectively adsorb CO on their surface. It is shown that the adsorption of CO yields a measurable shift in the natural frequency of the micro-cantilevers, which can be directly correlated with the concentration of CO in the gas mixture. It is determined that the maximum adsorption capacity of the sensor occurs at 40 °C using CuY zeolite with 10 wt% Cu content. Furthermore, the shift in the natural frequency of the sensor is observed to increase as the thickness of the zeolite layer is increased up to a threshold value corresponding to about a quarter of the thickness of the micro-cantilever. At this point, a clearly measurable shift of about 275 Hz in the natural frequency of the micro-cantilevers is observed. While the maximum frequency shift occurs using a relatively thick zeolite layer, it is observed that, for the range of thicknesses considered, the maximum frequency shift per unit weight of CO adsorbed (sensitivity) decreases as the thickness of the zeolite layer is increased. The methodology proposed in this paper could pave the way towards the development of a portable and self-contained unit to monitor the concentration of CO in a mixture of gases.

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Original perfluoropolyether (PFPE)-based oligomeric polyurethanes (FOPUs) with different macromolecular architecture were synthesized (in one step) as low-surface-energy materials. It is demonstrated that the oligomers, especially the ones terminated with CF3 moieties, can be employed as safer replacements to long-chain perfluoroalkyl substances/additives. The FOPU macromolecules, when added to an engineering thermoplastic (polyethylene terephthalate, PET) film, readily migrate to the film surface and bring significant water and oil repellency to the thermoplastic boundary. The best performing FOPU/PET films have reached the level of oil wettability and surface energy significantly lower than that of polytetrafluoroethylene, a fully perfluorinated polymer. Specifically, the highest level of the repellency is observed with an oligomeric additive, which was made using aromatic diisocyanate as a comonomer and has CF3 end-group. This semicrystalline oligomer has a glass transition temperature (Tg) well above room temperature, and we associate the superiority of the material in achieving low water and oil wettability with its ability to effectively retain CF3 and CF2 moieties in contact with the test wetting liquids.

We describe a straightforward approach to fabricating perfluoropolyether (PFPE)-based nanocoatings, significantly decreasing the spreading of oil and water on coated surfaces. In the fabrication, polyglycidyl methacrylate (PGMA) is used as an anchoring layer deposited on the silicon surface before PFPE attachment. Perfluoropolyether-based polyester acid (PFPE-COOH) is then grafted to the PGMA surface to reduce its surface energy and, consequently, wettability. The grafted surface demonstrates a hexadecane contact angle of 40–46° and a water contact angle of 80–98°. The surface’s wettability strongly depends on the grafted layer thickness, where grafting of the thicker PFPE layers results in lower oil and water wettability. We expect that the employment of PFPE-based grafted nanocoatings will eliminate the health and environmental concerns of long perfluoroalkyls, which are typically used to obtain surfaces with decreased spreading of oil and water.

Y üzey modifikasyonları, tekstil, elektronik, biyomedikal gibi uygulamalarda kullanılması üzere malzeme yüzeylerinin yapışma, ıslanabilirlik, sürtünme, biyouyumluluk vb. fiziksel ve kimyasal özelliklerini değiştirmek için gereklidir. Yüzey modifikasyonları genellikle katı substratlara polimer zincirlerinin aşılanmasıyla yapılır. Aşılama işlemi, polimerlerin kimyasal yapısını değiştirmeden yüzey özelliklerinin kontrolüne ve manipülasyonuna izin verir. Polimer fırçalarının kimyasal yapısının yanısıra, onların aşılanma yoğunluğu ve yüzeye tutturulmuş polimer zincirleri arasındaki ortalama mesafe de aşılanmış malzemelerin kullanım amacını etkileyen önemli parametrelerdir. Aşılı polimerlerin yüzey fonksiyonları aşılama tekniklerinin seçilmesiyle karakterize edilir. Fonksiyonel polimer fırçaların sentezi genellikle yüzeyde başlatılan kontrollü/yaşayan serbest radikal polimerizasyon tekniklerinden biri, yani Atom Transferi Radikal Polimerizasyonu (ATRP), Nitroksit Aracılı Polimerizasyon (NMP), Fotoiniferter Aracılı Polimerizasyon (PIMP) ve Tersinir Katılma Ayrılma Zincir Transfer Polimerizasyonu (RAFT) ile gerçekleştirilir. Bu derleme makalesinde, polimer fırçaların üretilmesinde kullanılan bu tekniklerin stratejileri rapor edilecek ve çeşitli alanlarda uygulanması özetlenecektir. Anahtar KelimelerPolimer fırçalar, atom transferi radikal polimerizasyonu, nitroksit aracılı polimerizasyon, fotoiniferter aracılı polimerizasyon, tersinir katılma ayrılma zincir transfer polimerizasyonu.

It is required to determine the factors that are dangerous in terms of occupational health and safety in hazardous waste disposal facilities, which is an area where multidisciplinary work is required. It is also needed to find solutions for preventing risks that may cause. In this study; probability, severity and frequency criteria were used as decision criteria and the importance weights of these criteria were determined with fuzzy analytical hierarchy process. Then, 46 risks identified for the five main processes such as entry of waste to the plant, waste analysis, intermediate storage of hazardous waste, disposal of hazardous waste, and auxiliary facilities; were evaluated by fuzzy TOPSIS method according to decision criteria and prioritized according to their level. It is found that the highest priority risks for all sub-process are “fire and explosion”.