Search the repository

A+ | A- | | SLO | ENG

Abstract: Nanocomposites are currently attracting significant attention in the energy sector, particularly for storage applications. However, controlling interfacial compatibility remains a challenge. This work introduces a novel interfacial functionalization strategy that enables the achievement of exceptional dielectric properties and addresses the persistent issue of poor filler–matrix interaction in nanocomposites. A poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) matrix was filled with lead-free BaTi0.89Sn0.11O3 (BTS11) nanoparticles, which exhibit ultra-high piezoelectric performance near ambient temperature. These nanoparticles were functionalized with various modifying agents, including ethylenediamine (EDA), polyvinylpyrrolidone (PVP), polydopamine (PDA), and 3-aminopropyltriethoxysilane (APS). The study demonstrated that the functionalized HO-BTS11@modifier/PVDF-HFP nanocomposites exhibit distinct dielectric characteristics depending on the modifying agent. The HO-BTS11@EDA/PVDF-HFP nanocomposites, which included hydroxylated HO-BTS11 nanoparticles modified with EDA, outperformed other modified systems with the maximum energy storage efficiency (~ 77%) and a dielectric permittivity of 70 at 1 kHz. EDA with small molecular size, low polarity, and ability to form hydrogen bonds enable improved interfacial adhesion with the hydrophobic PVDF-HFP matrix making the composite suitable for enhancing energy storage performance. This selective functionalization strategy not only provides new insights into interface engineering but also offers a promising pathway for the development of high-performance materials for energy storage and harvesting devices, embedded capacitors, flexible electronics, and next-generation dielectric systems.
Keywords: nanocomposites, interfacial functionalization, piezoelectric properties, dielectric properties
Published in DiRROS: 19.01.2026; Views: 415; Downloads: 89
Full text (1,10 MB)
This document has many files! More...

Abstract: During the COVID-19 pandemic, face masks were the first line of defense against the spread of infection. However, infectious viruses may remain on medical textiles, potentially serving as an additional source of infection. Due to their chemical inertness, many textiles cannot be enhanced with antiviral functionalities. Through treatment with low-pressure gaseous plasma, we have activated the surface of a medical-grade melt-blown, non-woven polypropylene textile so that it can absorb sodium dodecyl sulfate, an antimicrobial surfactant. Within two hours of contact time, the functionalized textile has been able to inactivate over 7 log10 PFU mL−1 of bacteriophage phi6, a surrogate of enveloped viruses such as SARS-CoV-2, and it has retained its antiviral properties for over 100 days. The functionalized material has not disrupted facial mask filtration efficiency or breathability. In addition, the in vitro biocompatibility testing in accordance with ISO 10993-5 for testing of medical devices has demonstrated that the selected formulation causes no adverse effects on the mouse fibroblast cell line L-929. With the treatment processes that have been completed within seconds, the method seems to have great potential to produce antiviral textiles against future outbreaks.
Keywords: surgical face masks, plasma functionalization, antiviral materials, virus filtration, breathability
Published in DiRROS: 07.10.2024; Views: 1366; Downloads: 947
Full text (4,16 MB)
This document has many files! More...

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: 1785; Downloads: 1065
Full text (4,42 MB)
This document has many files! More...