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Cellulose produced by bacteria (BC) is considered a promising material for the textile industry, but the fragile and sensitive nature of BC membranes limits their broad applicability. Production of all-cellulose biocomposites, in which the BC is cultivated in situ on a cotton fabric, could solve this problem, but here a new issue arises, namely poor adhesion. To overcome this challenge, cotton fabric was modified with low-pressure oxygen plasma in either afterglow, E-mode, or H-mode. All-cellulose biocomposites were prepared in situ by placing the samples of cotton fabric in BC culture medium and incubating for 7 days to allow BC microfibril networks to form on the fabric. Modification of cotton fabric with oxygen plasma afterglow led to additional functionalization with polar groups, and modification with oxygen plasma in H-mode led also to etching and surface roughening of the cotton fibers, which improved the adhesion within the biocomposite. In addition, these biocomposites showed higher deformation capacities. Modification of the cotton fabric over a longer period in E-mode was found to be unsuitable, as this caused strong etching, which led to the defibrillation of cotton fibers and poor adhesion of BC. This study highlights the potential of low-pressure plasma treatment as an environmentally friendly method to improve the performance of cellulose-based biocomposites. [ABSTRACT FROM AUTHOR]

Cellulose is an abundant natural polymer and is thus promising for enforcing biobased plastics. A broader application of cellulose fibers as a filler in polymer composites is limited because of their hydrophilicity and hygroscopicity. The recent scientific literature on plasma methods for the hydrophobization of cellulose materials is reviewed and critically evaluated. All authors focused on the application of plasmas sustained in fluorine or silicon-containing gases, particularly tetrafluoromethane, and hexamethyldisiloxane. The cellulose materials should be pre-treated with another plasma (typically oxygen) for better adhesion of the silicon-containing hydrophobic coating. In contrast, deposition of fluorine-containing coatings does not require pre-treatment, which is explained by mild etching of the cellulose upon treatment with F atoms and ions. The discrepancy between the results reported by different authors is explained by details in the gas phase and surface kinetics, including the heating of samples due to exothermic surface reactions, desorption of water vapor, competition between etching and deposition, the influence of plasma radiation, and formation of dusty plasma. Scientific and technological challenges are highlighted, and the directions for further research are provided. [ABSTRACT FROM AUTHOR]

This study presents an eco-friendly protocol for the hydrophilization of polyethylene terephthalate (PET) fabric and the in situ synthesis of ZnO particles. The alkaline medium and reducing agent for ZnO synthesis were prepared as aqueous extracts from wood ash and pomegranate peel, respectively. Due to the hydrophobic nature of the PET fabric, oxygen plasma treatment was included in the process. The influence of plasma treatment in different synthesis steps on the formation of ZnO and consequently on the morphological, colour and ultraviolet (UV) protective properties of the samples was discussed. The study showed that incorporating oxygen plasma treatment before immersing the samples in each solution for the ZnO in situ synthesis (natural alkaline medium of wood ash, zinc salt and natural reducing agent from pomegranate peel) produced PET fabric with the most uniform ZnO layer without visible cracks and the highest UV-blocking ability with a UV protection factor (UPF) of 300+. The colour measurements showed that increasing the number of plasma treatments leads to higher colour strength of the samples. Herein, a novel protocol for the production of protective PET fabrics is presented, which is also an example of a completely environmentally benign textile functionalization process. [ABSTRACT FROM AUTHOR]

Low-pressure oxygen plasma created by an electrodeless radiofrequency (RF) discharge was applied to modify the properties of cellulosic fibrous polymer (cotton) in order to improve adsorption properties towards zinc oxide (ZnO) nanoparticles and to achieve excellent ultraviolet (UV) protective properties of cotton fabric. The chemical and physical surface modifications of plasma-treated cotton fabric were examined by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The mechanical properties of plasma-treated samples were evaluated, measuring strength and elongation of the fabrics. The quantity of zinc on the ZnO-functionalized cotton samples was determined using inductively coupled plasma mass spectrometry (ICP-MS) and the effectiveness of plasma treatment for UV protective properties of cotton fabrics was evaluated using UV-VIS spectrometry, measuring the UV protection factor (UPF). The results indicated that longer plasma treatment times cause higher concentration of oxygen functional groups on the surface of fibres and higher surface roughness of fibres. These two conditions are crucial in increasing the content of ZnO nanoparticles on the fibres, providing excellent UV protective properties of treated cotton, with UPF factor up to 65.93. [ABSTRACT FROM AUTHOR]

Cotton fabric was exposed to low-pressure capacitively coupled plasma to enhance the adsorption and adhesion of fragrance microcapsules (FCM). Two plasma-forming gases, namely oxygen (O2) and nitrogen (N2), were investigated. The untreated and plasma-treated samples were investigated for their morphological changes by scanning electron microscopy (SEM), mechanical properties (breaking force, elongation, and flexural rigidity), and wicking properties. The cotton samples were functionalized with FCM and the effect of plasma pretreatment on the adsorption and adhesion of FCM was evaluated using SEM, air permeability, fragrance intensity of unwashed and washed cotton fabrics, and Fourier transform infrared spectroscopy (FTIR). The results show that the plasma containing either of the two gases increased the wicking of the cotton fabric and that the O2 plasma caused a slight etching of the fibers, which increased the tensile strength of the cotton fabric. Both plasma gases caused changes that allowed higher adsorption of FCM. However, the adhesion of FCM was higher on the cotton treated with N2 plasma, as evidenced by a strong fragrance of the functionalized fabric after repeated washing. [ABSTRACT FROM AUTHOR]

An overview of recent work on the low-temperature plasma-assisted synthesis of zinc oxide (ZnO) nanoparticles is presented and interpreted in terms of gas-phase and surface reactions with illustrated examples. The thermodynamical nonequilibrium conditions allow the formation of chemically reactive species with a potential energy of several eV, which readily interact with the Zn precursors and initiate reactions leading to the formation of nanoparticles or nanowires. The high-quality nanowires were synthesized from Zn powders only upon interaction with moderately ionized plasma in a narrow range of plasma parameters. This technique is promising for the synthesis of large quantities of nanowires with aspect ratios well above 10, but the exact range of parameters remains to be determined. Apart from the ex situ techniques, the ZnO nanoparticles can be synthesized by depositing a film of precursors (often Zn salts or Zn-containing organometallic compounds) and exposing them to oxygen plasma. This technique is useful for the synthesis of well-adherent ZnO nanoparticles on heat-sensitive objects but requires further scientific validation as it often leads to the formation of a semicontinuous ZnO film rather than nanoparticles. Both low-pressure and atmospheric plasmas are useful in converting the precursor film into ZnO nanoparticles despite completely different mechanisms. [ABSTRACT FROM AUTHOR]

This paper presents an in-depth study of the surface modification of polyethylene terephthalate fabric (PET) with non-thermal plasma and temperature- and pH-responsive nanogel (PNCS) to impart smart thermoregulation properties. To increase the adsorption of the PNCS nanogel onto the PET, ammonia and oxygen plasma and a combination of both plasma gases were used. Chemical changes caused by the plasma treatment were investigated using X-ray photoelectron spectroscopy (XPS), morphological changes were determined using scanning electron microscopy (SEM) and the swelling and de-swelling ability was determined by measuring the moisture content at 20 and 40 °C. The greatest deposition of the PNCS nanogel, with unimpaired swelling ability, was found on the oxygen-plasma-treated samples, as they had the highest O/C ratio. Meanwhile, the least promising results were found for the samples treated with a combination of oxygen and ammonia plasma, where the highest concentration of nitrogen was present on the fibre surface. Since the treatment with oxygen plasma proved to be the most effective method, different exposure times to the oxygen plasma, namely, 10, 30 and 60 s, were studied in the second part of this study. The optimal oxygen plasma treatment time was found to be 30 s, where the greatest deposition and unhindered swelling/de-swelling ability of the PNCS nanogel on the PET fabric was achieved. [ABSTRACT FROM AUTHOR]