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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]

New approaches are required in the agricultural sector to keep pace with the ever-growing demand for food in the context of climate change and resource deterioration and avoiding further negative impact on the environment. Nonthermal plasma is an environmentally-friendly technology which could make a difference in future agricultural production. This review intends to introduce the topic of plasma agriculture to a broad audience by describing in detail various plasma sources with potential for agricultural applications, as well as the effects of plasma exposure of seeds, both at the macroscopic scale, and concerning the intimate mechanisms occurring inside the plant. Examples meant to illustrate the plasma effect on seeds and plants have been selected among extensively investigated species, such as cereals and legumes, as well as among a few species that are less often reported in literature, such as medicinal plants and woody plants. Generally, the main effects for all types of seeds consist in increased germination, higher plant yield, seed decontamination, and sometimes higher tolerance to various stress factors. These effects are due to the physical and chemical plasma interaction with seeds followed by the response of cell mechanisms, which are addressed in detail in the paper. Finally, a few crucial aspects regarding the practical application of nonthermal plasma in agriculture are discussed to illustrate the challenges and perspective of such treatments. [ABSTRACT FROM AUTHOR]

Nanocellulose is among the most promising materials for enhancing the mechanical properties of polymer composites. Broad application is, however, limited by inadequate surface properties. A standard technique for tailoring the surface composition and wettability of polymers is a brief treatment with non-equilibrium gaseous plasma, but it often fails when treating materials with a large surface-to-mass ratio, such as cellulose nanofibers. In this paper, the theoretical limitations are explained, the approaches reported by different groups are reviewed, and the results are interpreted. The treatment of dry nanocellulose is limited by the ability of uniform treatment, whereas the plasma treatment of nanocellulose dispersed in liquids is a slow process. The methods for enhancing the treatment efficiency for both dry and water-dispersed nanocellulose are explained. [ABSTRACT FROM AUTHOR]

Carbon deposits consisting of vertically oriented multilayer graphene sheets on metallic foils represent an interesting alternative to activated carbon in electrical and electrochemical devices such as super-capacitors because of the superior electrical conductivity of graphene and huge surface–mass ratio. The graphene sheets were deposited on cobalt foils by plasma-enhanced chemical vapor deposition using propane as the carbon precursor. Plasma was sustained by an inductively coupled radiofrequency discharge in the H mode at a power of 500 W and a propane pressure of 17 Pa. The precursor effectively dissociated in plasma conditions and enabled the growth of porous films consisting of multilayer graphene sheets. The deposition rate varied with time and peaked at 100 nm/s. The evolution of surface wettability was determined by the sessile drop method. The untreated substrates were moderately hydrophobic at a water contact angle of about 110°. The contact angle dropped to about 50° after plasma treatment for less than a second and increased monotonously thereafter. The maximal contact angle of 130° appeared at a treatment time of about 30 s. Thereafter, it slowly decreased, with a prolonged deposition time. The evolution of the wettability was explained by surface composition and morphology. A brief treatment with oxygen plasma enabled a super-hydrophilic surface finish of the films consisting of multilayer graphene sheets. [ABSTRACT FROM AUTHOR]

Glow discharge optical emission spectroscopy (GDOES) is a useful technique for qualitative plasma characterization. It also enables depth profiling of solid materials upon exposure of samples to energetic positively charged ions from gaseous plasma, providing specifics of both surface- and gas-phase collision phenomena that are considered. The early stages of developing GDOES useful for the determination of surface composition and depth profiling of solid materials are reviewed and analyzed, stressing the contribution of early authors. The advantages as well as drawbacks of the GDOES technique are presented and discussed. The recent applications of this technique for depth profiling of various materials are presented, and the directions for constructing a laboratory-scale device are provided. [ABSTRACT FROM AUTHOR]