1. Colorimetric cutoff indication of relative humidity based on selectively functionalized mesoporous silicaErika Švara Fabjan, Peter Nadrah, Anja Ajdovec, Matija Tomšič, Goran Dražić, Matjaž Mazaj, Nataša Zabukovec Logar, Andrijana Sever Škapin, 2020, original scientific article Abstract: We present a novel % cutoff concept of colorimetric indication of relative humidity based on dye dissolution in condensed water in capillaries of selectively functionalized mesoporours host SiO2 material. Consistently high levels of indoor air humidity induces mold and algae growth which represent a potential risks for human health and have deteriorating effect on walls as well. Simple localized humidity detection of high humidity with naked eye especially at places with low air circulation, where growth of mold usually starts first, is therefore highly desirable. The reporting dye was integrated in the non-functionalized mesoporous silica matrix with different pore diameters and selective-functionalized mesoporous silica material. After exposure to the environment of different air humidities the dye dissolved in water causing color change of adsorbent. With the use of adsorbents with different mesopore diameters high ability to tune the value of relative humidity when complete capillary condensation occurred was achieved. Materials with pore diameters of 3.0%nm, 3.5%nm and 7.0%nm exhibit gradual color change when reaching relative humidity up to 55, 79 and 88 RH% respectively. After selective methylation of the material with 7.0%nm pore diameter, non-gradual cutoff color change was achieved. Sample exhibited color change at narrow range of relative humidity (cutoff color change). Due to selective functionalized outer surface the dye dissolution occur only in condensed water in pores and therefore provide colorimetric indication only in this range. Selectively modified silica material has a great potential for a straightforward detection of high humid environment.
Keywords: turn-on colorimetric probe, selective functionalization, mesoporous silica, relative humidity, capillary condensation
Published in DiRROS: 05.09.2023; Views: 297; Downloads: 218
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2. Advanced method for efficient functionalization of polymers by intermediate free-radical formation with vacuum-ultraviolet radiation and producing superhydrophilic surfacesAlenka Vesel, Rok Zaplotnik, Miran Mozetič, Nina Recek, 2023, original scientific article Abstract: An efficient approach for tailoring surface properties of polymers is presented, which enables rapid modification leading to superhydrophilic properties. The approach is based on vacuum-ultraviolet radiation (VUV) pretreatment of the surface to create reactive dangling bonds. This step is followed by a second treatment using neutral oxygen atoms that react with the dangling bonds and form functional groups. The beneficial effect of VUV pretreatment for enhanced functionalization was clearly demonstrated by comparing VUV pretreatment in plasmas created in different gases, i.e., hydrogen, nitrogen, and oxygen, which differ in the intensity of VUV/UV radiation. The emission intensity of VUV radiation for all gases was measured by vacuum ultraviolet spectroscopy. It was shown that VUV has a strong influence on the treatment time and final surface wettability. A superhydrophilic surface was obtained only if using VUV pretreatment. Furthermore, the treatment time was significantly reduced to only a second of treatment. These findings show that such an approach may be used to enhance the surface reaction efficiency for further grafting of chemical groups.
Keywords: plasma treatment, vacuum-ultraviolet radiation treatment, surface functionalization, polymer polyvinyl chloride, vacuum-ultraviolet spectroscopy, vacuum-ultraviolet photons
Published in DiRROS: 06.06.2023; Views: 372; Downloads: 187
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3. Structural and CO [sub] 2 capture properties of ethylenediamine-modified HKUST-1 metal-organic frameworkNika Vrtovec, Matjaž Mazaj, Gianpiero Buscarino, Angela Terracina, Simonpietro Agnello, Iztok Arčon, Janez Kovač, Nataša Zabukovec Logar, 2020, original scientific article Keywords: functionalization, modification, adsorption, extended X-ray absorption fine structure, materials
Published in DiRROS: 25.11.2020; Views: 2314; Downloads: 957
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