Germination Improvement of Three Pine Species (Pinus) After Diffuse Coplanar Surface Barrier Discharge Plasma Treatment

Seed modification by atmospheric pressure non-thermal plasma treatment was tested on pine species. The Diffuse Coplanar Surface Barrier Discharge (DCSBD) with expose times of 0 s, 1 s, 3 s, 5 s, 10 s, 30 s, 60 s was used on seed treatment of Pinus sylvestris, Pinus nigra and Pinus mugo. The effect of plasma treatment on the chemical bonds on the seed surface was studied using the Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR). Characteristics of seed germination and early growth were measured. ATR-FTIR surface diagnostics did not show any damage. Changes in the peak intensities indicated the presence of oxygen and nitrogen-containing groups, or a reduction of the lipid layer on the surface. Various statistically significant effects of the three species of seeds treated with DCSBD treatment were recorded. No significant differences were found between control sample and plasma treated ones, but some positive trends were obtained. Positive trends were recorded in germinated and growing seeds of all three species mainly after 3 s exposures. Exposure times from 10 s had an inhibitory effect. Based on the results obtained, it can be recommended that forest nurseries performance of nonthermal plasma modification of seeds should be evaluated to measure the durability of the observed growth characteristics.

     

Effect of Plasma Treatment on Surface Wettability of Wheat Seeds

High Energy Chemistry - It has been shown that as a result of surface treatment of seeds in nonthermal atmospheric-pressure glow-discharge plasma, the surface becomes hydrophilic and is...     

Expanded poly(tetrafluoroethylene) membrane surface modification using acetylene/nitrogen plasma treatment

In this article, expanded poly(tetrafluoroethylene) (e-PTFE) membrane surface modification was carried out using acetylene/nitrogen plasma treatment (p-e-PTFE). The variation in surface morphology of the p-e-PTFE membranes was confirmed by FTIR-ATR, scanning electron microscopy (SEM), and contact angle measurements. It was found that the surface hydrophilicity increased with increasing nitrogen content in the feed gas mixture, RF power, and plasma treatment time. The surface pore size decreased with increasing RF power and plasma treatment time. The water contact angles of the modified e-PTFE membrane decreased from 125.8° to 34.1° through the acetylene/nitrogen plasma treatment.     

羊毛表面改性对拒水拒油整理的作用及机理研究

应用扫描电镜(SEM)、X射线光电子能谱(XPS)和衰减全反射红外光谱(FTIR-ATR)等现代表面分析技术研究不同改性处理羊毛表面的化学和物理结构特性.SEM研究结果表明,经低温等离子体表面改性或特定化学改性后的羊毛鳞片表面呈现纳米尺度的沟槽和凹凸结构,应用Wenzel公式和Cassie and Baxter公式阐述了表面粗糙度与接触角的关系,揭示了羊毛表面改性对于提高拒水拒油整理效果的原因所在.XPS和FTIR-ATR研究表明,上述物理和化学的表面改性技术使羊毛表面的二硫键氧化断裂和表面类脂物质改性/除去,促进拒水拒油整理剂的吸附和固着.表面改性和拒水拒油整理的协同效应赋予羊毛类荷叶效应,使其呈现超级拒水拒油拒污功能.     

Effects of Oxygen (O2) Plasma Treatment in Promoting the Germination and Growth of Chili

In general, seed germination is improved by low-pressure plasma treatment using precursors such as air, nitrogen, O_2, and argon, etc. For the first time, low-pressure O₂ plasma was used to treat chili seeds in this study. When compared to untreated and vacuum-treated seeds, O₂ plasma treatment using the discharge power of 80 W for 60 s significantly improves chili seed germination and growth. The effect of vacuum on the germination and growth of chili seeds was also studied and shown to be negligible. The physical and chemical changes induced by O₂ plasma treatment were investigated to understand the plasma treatment to germination improvement. Combinatory etching and chemical modification aided imbibition and increased germination percentage in this O₂ plasma treatment on chili seeds. The success of this method has the potential to be scaled up to solve food security issues with seeds that would otherwise struggle to germinate.

     

Effect of Cold Atmospheric Pressure Plasma on the Wheat Seedlings Vigor and on the Inactivation of Microorganisms on the Seeds Surface

Effects of a cold atmospheric pressure plasma (CAPP) treatment on the germination, production of biomass, vigor of seedlings, uptake of water of wheat seeds (Triticum aestivum L. cv. Eva) were investigated. The CAPP treatment influence on the inactivation of microorganisms occurring on the surface of wheat seeds was investigated also. The so-called Diffuse Coplanar Surface Barrier Discharge generating a cold plasma in ambient air with high power volume density of some 100 W/cm³ was used for the treatment of seeds at exposure times in the range of 10–600 s. The optical emission spectroscopy and the electrical measurements were used for estimation of CAPP parameters. The obtained results indicate that the germination rate, dry weight and vigor of seedlings significantly increased for plasma treatment from 20 to 50 s. The plasma treatment of seeds led to an extensive increase in wettability and faster germination comparing with the untreated seeds. The growth inhibition effect of CAPP on the surface microflora of wheat seeds increased with the increase of the treatment time. The efficiency of the treatment of wheat seeds artificially contaminated with pure cultures of filamentous fungi decreased in the following order: Fusarium nivale > F. culmorum > Trichothecium roseum > Aspergillus flavus > A. clavatus.     

Effect of Cold Atmospheric Pressure Plasma on Maize Seeds: Enhancement of Seedlings Growth and Surface Microorganisms Inactivation

Cold atmospheric pressure ambient air plasma generated by Diffuse Coplanar Surface Barrier Discharge (DCSBD) was investigated for inhibition of native microbiota and potentially dangerous pathogens (Aspergillus flavus, Alternaria alternata and Fusarium culmorum) on the maize surface. Moreover, the improvement of germination and growth parameters of maize seeds was evaluated. Maize (Zea mays L.; cv. Ronaldinio), one of the most important cultivated crops worldwide, was selected as the research material. Electrical measurements confirmed the high volume power density (80 W cm^?3) of DCSBD plasma. Non-equilibrium plasma state evaluated using optical emission spectroscopy showed values of vibrational and rotational temperature (2700?±?300) K and (370?±?75) K, respectively. Changes on the plasma treated seeds surface were studied by water contact angle measurement, scanning electron microscope analysis and Fourier transform infrared spectroscopy. A complete devitalisation of native microbiota on the surface of seeds was observed after a short treatment time of 60 s (bacteria) and 180 s (filamentous fungi). The plasma treatment efficiency of artificially contaminated maize seeds was estimated as a reduction of 3.79 log (CFU/g) in F. culmorum after a 60-s plasma treatment, 4.21 log (CFU/g) in A. flavus and 3.22 log (CFU/g) in A. alternata after a 300-s plasma treatment. Moreover, the obtained results show an increase in wettability, resulting in a better water uptake and in an enhancement of growth parameters. The investigated DCSBD plasma source provides significant technical advantages and application potential for seed surface finishing without the use of hazardous chemicals.     

连续纤维增强含二氮杂萘酮联苯结构聚芳醚砜酮树脂基复合材料的界面

利用射频感性耦合冷等离子体(ICP)处理技术改性连续纤维表面,分别采用X射线光电子能谱(XPS)、原子力显微镜(AFM)及动态接触角分析(DCA)系统研究了等离子体处理时间、放电气压、放电功率等工艺参数对连续碳纤维、芳纶纤维和对亚苯基苯并二噁唑(PBO)纤维的表面化学成分、表面形貌、表面粗糙度及表面自由能的影响.研究结...     

A Comparison of PE Surfaces Modified by Plasma Generated Neutral Nitrogen Species and Nitrogen Ions

The surface modification of polyethylene (PE) by neutral nitrogen species (ground and excited state N₂ as well as atomic N; modified nitrogen plasma treatment) has been compared to the effect of nitrogen ion bombardment using X-ray Photoelectron Spectroscopy (XPS) and contact angle measurements. XPS results indicate that a greater nitrogen concentration was grafted during the modified nitrogen plasma treatment of PE, an effect that was attributed to surface sputtering during ion beam modification. The distribution of nitrogen-containing functionalities was strongly dependent upon the treatment strategy; the modified nitrogen plasma treatment lead predominantly to imine groups being formed at the PE surface, while amine groups were the dominant species produced during ion beam modification. The presence of electron irradiation during the modified nitrogen plasma treatment of PE did not modify the rate of nitrogen incorporation or change the nature of N-containing functional groups produced but did lead to a systematic decrease in contact angle.     

Surface characterisation of oxygen plasma treated electrospun polyurethane fibres and their interaction with red blood cells

In this work, the effects of oxygen plasma surface modification have been studied on electrospun polyether-based polyurethane in order to investigate the imposed limitations and possibilities to improve surface characteristics on fibrous assemblies. The evolution of induced changes in surface morphology, chemistry and wettability by the plasma treatment has been characterised for increasing plasma exposure time using scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and water contact angle measurements. Significant reduction in fibre diameter concomitant with progressing rough surface textures are found on the fibres in surface layers during early treatment phases while extended exposure eventually causes the fibre structure to deteriorate. Surface oxygen content and functionalities such as carbonyl and carboxyl increase slightly with longer treatments until loss of material integrity occurs. The results have also shown that oxygen plasma rapidly alters the initially strong hydrophobic character of the non-woven fibres to hydrophilic behaviour, allowing water penetration into the network, but without significant changes for increased exposure time. In addition, the response of red blood cell shape to pristine and oxygen plasma treated fibres were found to be similar. In both cases, a population of cells having fibre contact displayed protrusions while measurements showed that the cell function remain intact and indicated that the adhesion was non-specific. The reported findings yield useful process knowledge that can support the formation of well-defined fibre architectures and are valuable in the designs of electrospun polyurethane material systems utilising oxygen plasma surface modification.     

Non-thermal Plasma as a Priming Tool to Improve the Yield of Pea in Outdoor Conditions

Seed priming is a pre-treatment of seeds leading to the improvement of their germination, the plant growth, and the product yield. In this study we investigated the possibility of the use of non-thermal plasma operating in atmospheric pressure air for seed priming with the objective to improve the yield of pea seeds. Two priming ways were used: an indirect way by using plasma activated water (PAW) generated by the transient spark discharge with water electrospray or the glow discharge batch treatment and a direct exposure of seeds to the pulsed corona discharge. After treatment, the seeds were planted in the outdoor field for about 14 weeks until harvest. The direct plasma treatment resulted in two key results: the strong effectiveness of the pulsed corona plasma improving the yield, and the long-term effect of the plasma seed treatment. The results of the indirect treatment showed that the pea plants from the seeds primed using PAW gained some improved growth parameters, especially the number of seeds per pod and the total number of seeds per plant. The scanning electron microscopy analysis showed that PAW and direct treatment induced some morphology changes at the surface of the pea seeds. This study documents a long-term effect of non-thermal plasma seed priming and contributes to the plasma agriculture applications by suggesting the implementation of non-thermal plasma direct or indirect treatments into the field.

     

Plasma Treated Sepiolite: A New Adsorbent for Removal of Malachite Green from Contaminated Water

Surface modification of clay materials has become an important issue to improve the efficiency of the adsorbent. The adsorption capacity of the clay material can be increased by thermal or chemical modifications. In this study, plasma technology was applied for the surface modification of sepiolite to improve the removal of malachite green from contaminated water. This study is novel in preparing and examining the effectiveness of sepiolite in adsorption of malachite green from contaminated water. To achieve the aim, plasma application time, CO₂, N₂, or Ar plasma gases effect and pH were investigated with respect to the adsorption capacity of MG. The surface properties of raw and plasma treated sepiolite were investigated with SEM, FTIR, BET surface area and XRD measurements. The monolayer adsorption capacity was found to be 143 mg/g.     

聚甲基戊烯膜式氧合器表面碳酸酐酶的固定化及性能研究

聚甲基戊烯(PMP)膜式氧合器表面先用水等离子体改性,以引入羟基官能团;再以溴化氰为偶联剂,将碳酸酐酶(CA)偶联至其表面.改性后用X射线光电子能谱(XPS)、表面接触角及酶活性测定等方法研究PMP表面性能变化.结果表明,等离子体处理后,在PMP表面引入了大量的含氧官能团,与水的表面接触角从103.37°降低至50.01°.再将CA引入PMP表面后,与水的表面接触角进一步降低至39.23°;XPS的C1谱图中出现蛋白质的特征峰;以对硝基苯酚乙酸酯为底物,测得表面接枝CA的活性达到理论单分子层接枝活性的73%.改性后PMP表面物理化学性质的变化证明本文方法确实能成功地将羟基官能团、CA引入其表面.本方法有望应用在膜式氧合器上以提高其清除血液中CO2的能力.     

Surface modification of polyester by oxygen‐ and nitrogen‐plasma treatment

In this paper, we present a study on the surface modification of polyethyleneterephthalate (PET) polymer by plasma treatment. The samples were treated by nitrogen and oxygen plasma for different time periods between 3 and 90 s. The plasma was created by a radio frequency (RF) generator. The gas pressure was fixed at 75 Pa and the discharge power was set to 200 W. The samples were treated in the glow region, where the electrons temperature was about 4 eV, the positive ions density was about 2 × 10¹⁵ m^?3, and the neutral atom density was about 4 × 10²¹ m^?3 for oxygen and 1 × 10²¹ m^?3 for nitrogen. The changes in surface morphology were observed by using atomic force microscopy (AFM). Surface wettability was determined by water contact angle measurements while the chemical composition of the surface was analyzed using XPS. The stability of functional groups on the polymer surface treated with plasma was monitored by XPS and wettability measurements in different time intervals. The oxygen‐plasma‐treated samples showed much more pronounced changes in the surface topography compared to those treated by nitrogen plasma. The contact angle of a water drop decreased from 75° for the untreated sample to 20° for oxygen and 25° for nitrogen‐plasma‐treated samples for 3 s. It kept decreasing with treatment time for both plasmas and reached about 10° for nitrogen plasma after 1 min of plasma treatment. For oxygen plasma, however, the contact angle kept decreasing even after a minute of plasma treatment and eventually fell below a few degrees. We found that the water contact angle increased linearly with the O/C ratio or N/C ratio in the case of oxygen or nitrogen plasma, respectively. Ageing effects of the plasma‐treated surface were more pronounced in the first 3 days; however, the surface hydrophilicity was rather stable later. Copyright © 2008 John Wiley & Sons, Ltd.     

Surface modification of plasma‐pretreated expanded poly (tetrafluroethylene) films by graft copolymerization

A two‐step process based on a low‐pressure helium plasma treatment followed by acrylic acid‐grafting copolymerization was used for the surface modification of expanded polytetrafluoroethylene (ePTFE) films. The effects of plasma treatment power and treatment time on the hydrophilicity of the film surface were investigated. The wettability of the ePTFE film surface was characterized by water contact angle, and the surface compositions of the untreated and treated ePTFE samples were evaluated by atomic force microscopy and XPS. Contact angle measurements revealed that the hydrophilicity of the ePTFE film surface was greatly enhanced by the combined actions of the plasma treatment and acrylic acid grafting, and the contact angle decreased from 145° to 66°. Atomic force microscopy analyses showed that the surface roughness increased after the plasma treatment. XPS analyses showed substantial increase in the concentration of carbon and oxygen atoms and a decrease in the concentration of fluorine atoms at the film surface. T‐peel strength showed an improved bonding strength between the film and an adhesive tape after the treatment. Copyright © 2012 John Wiley & Sons, Ltd.     

Polyelectrolyte Adsorption on NH3-Plasma-Treated Poly(tetrafluoroethylene-co-hexafluoropropylene)

A two-step procedure for a permanently hydrophilic surface modification of poly(tetrafluoroethylene-co-hexafluoropropylene) (FEP, fluorinated ethylene propylene) was studied. In the first step a cationic polymer surface was created by low-pressure ammonia plasma treatment introducing nitrogen-containing functional groups. Afterwards, the anionic poly(sodium 4-styrenesulfonate) was adsorbed onto the plasma-treated FEP surface. The adsorption was assumed to be controlled by ionic interactions. The modification effects and their long-term behavior were evaluated by means of water contact angle goniometry. Furthermore, electrokinetic measurements and X-ray photoelectron spectroscopy were used for surface characterization.     

Surface modification of polymeric ultrafiltration membranes I. Effect of atmospheric pressure barrier discharge in air onto some characteristics of polyacrylonitrile ultrafiltration membranes

Atmospheric pressure plasma surface modification of polyacrilonitrile ultrafiltration membranes is presented here aimed at improvement of some basic working characteristics of the membranes such as productivity and selectivity. The effect of the barrier dielectric discharge voltage and the treatment duration onto the physical chemical characteristics of the membrane surface was studied. XPS analysis was employed to control the alteration of the membrane surface chemical composition. Contact angle measurement was used to characterize the hydrophilic/hydrophobic balance on the surface. Membrane structure was imaged by SEM observations.     

Stability and ageing of plasma treated poly(tetrafluoroethylene) surfaces

In this study CO₂, H₂/H₂O and H₂O low pressure plasma treatment of poly(tetrafluoroethylene) (PTFE) foils and of thin plasma deposited fluorocarbon polymer (PDFP) films with a structure close to PTFE was investigated. The properties of the plasma were analyzed by mass spectroscopy (MS) and optical emission spectroscopy (OES). The modified fluorocarbon surfaces were characterized by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), fourier transform infrared (FTIR) spectroscopy, spectroscopic ellipsometry, electrokinetic measurements and dynamic contact angle measurements in order to find optimized treatment conditions. The results of the surface modification were compared with respect to the efficiency of the plasma treatment and the stability of the modification effect at different ambient conditions. It was shown that the H₂O plasma treatment is the most effective process for the intended modification. The hydrophobic PTFE surface was converted into a more hydrophilic one. The introduced radicals after the H₂O plasma treatment can be utilized subsequently for post plasma reactions such as grafting processes.     

Chemical and physical analysis of cotton fabrics plasma-treated with a low pressure DC glow discharge

This paper focuses on the modification of cotton fabrics using a low pressure DC glow discharge obtained in air. The influence of different operating parameters such as treatment time, discharge power and operating pressure on the chemical and physical properties of the cotton fabrics is studied in detail. Surface analysis and characterization of the plasma-treated cotton fabrics is performed using vertical wicking experiments, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and weight loss measurements. The cotton fabrics show a significant increase in wicking behaviour; an effect which increases with increasing treatment time, increasing discharge power and increasing pressure. Results also show that low pressure DC glow treatment leads to surface erosion of the cellulose fibres, accompanied by an incorporation of oxygen-containing groups (C–O, C=O, O–C–O and O–C=O) on the cotton fibres. The DC glow treatment has thus the potential to influence not only the chemical but also the physical properties of cotton fabrics and this without the use of water or chemicals.     

Surface modification of expanded poly(tetrafluoroethylene) by means of microwave plasma treatment for improvement of adhesion and growth of human endothelial cells

Surface modification of expanded poly(tetrafluoroethylene) (ePTFE) vascular prostheses was carried out by means of low pressure microwave plasma treatment. Hydrogen/ water vapour mixtures (containing excess of hydrogen) were shown to be efficient with respect to functionalization of PTFE. The results of treatments in dependence on various gas pressures and treatment times were detected by physicochemical techniques (zeta potential, wetting measurements) and by surface spectroscopy (XPS, ATR-FTIR). Furthermore, adhesion and proliferation of human endothelial cells from umbilical cord (HUVEC) onto modified ePTFE were observed in vitro in culture media. The results of this biological test of plasma treated materials correlate well with physicochemical surface parameters.