scholarly journals Surface Modification of Polyamides by Gaseous Plasma—Review and Scientific Challenges

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3020
Author(s):  
Gregor Primc
Keyword(s):  
Surface Modification ◽  
Oxygen Concentration ◽  
Treatment Time ◽  
Plasma Reactor ◽  
Prolonged Treatment ◽  
Water Contact ◽  
Static Water ◽  
Nitrogen Concentrations ◽  
Polar Functional Groups ◽  
Almost All

A review of the most significant scientific achievements in the field of surface modification of polyamides by non-equilibrium plasma treatments is presented. Most authors employed atmospheric pressure discharges and reported improved wettability. The super-hydrophilic surface finish was only achieved using a low-pressure plasma reactor and prolonged treatment time, enabling both the nanostructuring and functionalization with polar functional groups. The average increase of the oxygen concentration as probed by XPS was about 10 at%, while the changes in nitrogen concentrations were marginal in almost all cases. The final static water contact angle decreased with the increasing treatment time, and the oxygen concentration decreased with the increasing discharge power. The need for plasma characterization for the interpretation of experimental results is stressed.

scholarly journals Surface modification of polyamide by 50 Hz dielectric barrier discharge (DBD) produced in air at atmospheric pressure

BIBECHANA ◽  
2021 ◽  
Vol 18 (1) ◽  
pp. 19-25
Author(s):  
Rajesh Prakash Guragain ◽  
Hom Bahadur Baniya ◽  
Santosh Dhungana ◽  
Bishnu Prasad Pandey ◽  
Ujjwal Man Joshi ◽  
...  
Keyword(s):  
Contact Angle ◽  
Surface Modification ◽  
Dielectric Barrier Discharge ◽  
Atmospheric Pressure ◽  
Barrier Discharge ◽  
Treatment Time ◽  
Industrial Applications ◽  
Polar Component ◽  
Water Contact ◽  
Dielectric Barrier

Industrial applications of the dielectric barrier discharge (DBD) have a long tradition. However, lack of understanding in some of its fundamental issues, such as the stochastic behaviors, is still a challenge for DBD researchers. The work was carried out at line frequency, 15 kV and at atmospheric pressure. This work focuses on the study of the electrical and optical characteristics of DBD at atmospheric pressure to determine a suitable condition for utilization of the device for surface modification of polyamides (PA) (Nylon 6/6). In this work, films were treated by dielectric barrier discharge and the effects on the morphology and chemistry of the material was studied. Surface characteristics were examined via contact angle measurements and SEM. The wettability tests revealed the improvement of the hydrophilic character of the surface of polyamide films as the water contact angle measured after the plasma treatments significantly decreased. The corresponding changes of the total surface energy revealed a significant increase in its polar component. The improvement of the wettability of PA strongly depends on the treatment time. The outcomes of the experiments proved that the modification of surface properties via plasma treatment reach to its saturation point after certain treatment time thus reducing the necessity of further treatment. BIBECHANA 18 (2021) 19-25

scholarly journals Plasma Activation of Polyethylene Powder

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2099
Author(s):  
Hana Šourková ◽  
Petr Špatenka
Keyword(s):  
Oxygen Concentration ◽  
Photoelectron Spectroscopy ◽  
Surface Composition ◽  
Treatment Time ◽  
Plasma Reactor ◽  
Particle Diameter ◽  
Dust Particles ◽  
Average Particle ◽  
Experimental Conditions ◽  
Polyethylene Powder

Polyethylene powder of average particle diameter of 160 µm was activated in a plasma reactor made from aluminum of volume 64 dm3 at the pressure 100 Pa. Dense oxygen plasma was sustained with a microwave discharge powered by a pulsed magnetron source of power 1 kW mounted onto the top flange of the plasma reactor. Polymer powder was treated in a batch mode with 0.25 kg/batch. The powder was placed into a stainless-steel dish mounted in the center of the reactor where diffusing plasma of low ion density, and the O-atom density of 2 × 1021 m−3 was sustained. The powder was stirred in the dish at the rate of 40 rpm. The evolution of powder wettability versus treatment time was measured using the Washburne method, and the surface composition was determined by X-ray Photoelectron Spectroscopy (XPS). The wettability versus the oxygen concentration assumed a parabolic behavior. The maximal oxygen concentration, as revealed by XPS, was 17.5 at.%, and the maximal increase of wettability was 220%. The efficiency of O-atoms utilization in these experimental conditions was about 10% taking into account the spherical geometry of dust particles and perfectly smooth surface. The method is scalable to large industrial systems.

scholarly journals Plasma Surface Modification of Epoxy Polymer in Air DBD and Gliding Arc

Processes ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 104
Author(s):  
Panagiotis Dimitrakellis ◽  
François Faubert ◽  
Maxime Wartel ◽  
Evangelos Gogolides ◽  
Stéphane Pellerin
Keyword(s):  
Contact Angle ◽  
Surface Modification ◽  
Plasma Treatment ◽  
Water Contact Angle ◽  
Epoxy Polymer ◽  
Plasma Reactor ◽  
Polymer Surface ◽  
Water Contact ◽  
Plasma Sources ◽  
Gliding Arc

We studied the epoxy polymer surface modification using air plasma treatment in a Gliding Arc (GA) plasma reactor and a pulsed Dielectric Barrier Discharge (DBD). We employed optical emission spectroscopy (OES) measurements to approximate the vibrational and rotational temperatures for both plasma sources, as well as surface temperature measurements with fiber optics and IR thermography to corelate with the corresponding hydrophilization of the epoxy material. Water contact angle measurements revealed a rapid hydrophilization for both plasma sources, with a slightly more pronounced effect for the air DBD treatment. Ageing studies revealed stable hydrophilicity, with water contact angle saturating at values lower than 50°, corresponding to a >50% decrease compared to the untreated epoxy polymer. ATR-FTIR spectroscopy studies showed an additional absorption band assigned to carbonyl group, with its peak intensity being higher for the DBD treated surfaces. The spectra were also correlated with the surface functionalization via the relative peak area ratio of carbonyl to oxirane and benzene related bands. According to SEM imaging, GA plasma treatment led to no apparent morphological change, contrary to DBD treatment, which resulted in nano-roughness formation. The enhanced surface oxidation as well as the nano-roughness formation on epoxy surface with the air DBD treatment were found to be responsible for the stable hydrophilization.

scholarly journals Plasma-Induced Fibrillation and Surface Functionalization of Cellulose Microfibrils

2021 ◽  
Vol 11 (1) ◽  
pp. 2
Author(s):  
Pieter Samyn
Keyword(s):  
Surface Modification ◽  
Treatment Time ◽  
Plasma Reactor ◽  
Cellulose Microfibrils ◽  
Plasma Modification ◽  
Critical Ratio ◽  
Hydroxyl Groups ◽  
Cellulose Structure ◽  
Selection Of

The classical production of microfibrillar cellulose involves intensive mechanical processing and discontinuous chemical treatment in solvent-based media in order to introduce additional chemical surface modification. By selecting appropriate conditions of a pulsed plasma reactor, a solvent-free and low-energy input process can be applied with the introduction of microcrystalline cellulose (MCC) and maleic anhydride (MA) powders. The plasma processing results in the progressive fibrillation of the cellulose powder into its elementary fibril structure and in-situ modification of the produced fibrils with more hydrophobic groups that provide good stability against re-agglomeration of the fibrils. The selection of a critical ratio MA/MCC = 2:1 allows separating the single cellulose microfibrils with changeable morphologies depending on the plasma treatment time. Moreover, the density of the hydrophobic surface groups can be changed through a selection of different plasma duty cycle times, while the influence of plasma power and pulse frequency is inferior. The variations in treatment time can be followed along the plasma reactor, as the microfibrils gain smaller diameter and become somewhat longer with increasing time. This can be related to the activation of the hierarchical cellulose structure and progressive diffusion of the MA within the cellulose structure, causing progressive weakening of the hydroxyl bonding. In parallel, the creation of more reactive species with time allows creating active surface sites that allow for interaction between the different fibrils into more complex morphologies. The in-situ surface modification has been demonstrated by XPS and FTIR analysis, indicating the successful esterification between the MA and hydroxyl groups at the cellulose surface. In particular, the crystallinity of the cellulose has been augmented after plasma modification. Furthermore, AFM evaluation of the fibrils shows surface structures with irregular surface roughness patterns that contribute to better interaction of the microfibrils after incorporation in an eventual polymer matrix. In conclusion, the combination of physical and chemical processing of cellulose microfibrils provides a more sustainable approach for the fabrication of advanced nanotechnological materials.

The Safety and Antimicrobial Properties of Stabilized Hypochlorous Acid in Acetic Acid Buffer for the Treatment of Acute Wounds—a Human Pilot Study and In Vitro Data

2021 ◽  
pp. 153473462110156
Author(s):  
Ewa A. Burian ◽  
Lubna Sabah ◽  
Klaus Kirketerp-Møller ◽  
Elin Ibstedt ◽  
Magnus M. Fazli ◽  
...  
Keyword(s):  
Pilot Study ◽  
Hypochlorous Acid ◽  
Treatment Time ◽  
Donor Site ◽  
Antimicrobial Properties ◽  
Prolonged Treatment ◽  
Wound Irrigation ◽  
The Mean ◽  
And Performance

Acute wounds may require cleansing to reduce the risk of infection. Stabilized hypochlorous acid in acetic buffer (HOCl + buffer) is a novel wound irrigation solution with antimicrobial properties. We performed a first-in-man, prospective, open-label pilot study to document preliminary safety and performance in the treatment of acute wounds. The study enrolled 12 subjects scheduled for a split-skin graft transplantation, where the donor site was used as a model of an acute wound. The treatment time was 75 s, given on 6 occasions. A total of 7 adverse events were regarded as related to the treatment; all registered as pain during the procedure for 2 subjects. One subject had a wound infection at the donor site. The mean colony-forming unit (CFU) decreased by 41% after the treatment, and the mean epithelialization was 96% on both days 14 (standard deviation [SD] 8%) and 21 (SD 10%). The study provides preliminary support for the safety, well-tolerance, and efficacy of HOCl + buffer for acute wounds. The pain was frequent although resolved quickly. Excellent wound healing and satisfying antimicrobial properties were observed. A subsequent in vitro biofilm study also indicated good antimicrobial activity against Pseudomonas aeruginosa with a 96% mean reduction of CFU, when used for a treatment duration of 15 min ( P < .0001), and a 50% decrease for Staphylococcus aureus ( P = .1010). Future larger studies are needed to evaluate the safety and performance of HOCl + buffer in acute wounds, including the promising antimicrobial effect by prolonged treatment on bacterial biofilms.

scholarly journals Osseointegration Improvement of Co-Cr-Mo Alloy Produced by Additive Manufacturing

Pharmaceutics ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 724
Author(s):  
Amilton Iatecola ◽  
Guilherme Arthur Longhitano ◽  
Luiz Henrique Martinez Antunes ◽  
André Luiz Jardini ◽  
Emilio de Castro Miguel ◽  
...  
Keyword(s):  
Surface Modification ◽  
Additive Manufacturing ◽  
Bone Ingrowth ◽  
Orthopedic Implants ◽  
Coated Sample ◽  
High Mechanical Strength ◽  
Coated Surface ◽  
Surface Modification Techniques ◽  
Almost All ◽  
Cobalt Base

Cobalt-base alloys (Co-Cr-Mo) are widely employed in dentistry and orthopedic implants due to their biocompatibility, high mechanical strength and wear resistance. The osseointegration of implants can be improved by surface modification techniques. However, complex geometries obtained by additive manufacturing (AM) limits the efficiency of mechanical-based surface modification techniques. Therefore, plasma immersion ion implantation (PIII) is the best alternative, creating nanotopography even in complex structures. In the present study, we report the osseointegration results in three conditions of the additively manufactured Co-Cr-Mo alloy: (i) as-built, (ii) after PIII, and (iii) coated with titanium (Ti) followed by PIII. The metallic samples were designed with a solid half and a porous half to observe the bone ingrowth in different surfaces. Our results revealed that all conditions presented cortical bone formation. The titanium-coated sample exhibited the best biomechanical results, which was attributed to the higher bone ingrowth percentage with almost all medullary canals filled with neoformed bone and the pores of the implant filled and surrounded by bone ingrowth. It was concluded that the metal alloys produced for AM are biocompatible and stimulate bone neoformation, especially when the Co-28Cr-6Mo alloy with a Ti-coated surface, nanostructured and anodized by PIII is used, whose technology has been shown to increase the osseointegration capacity of this implant.

scholarly journals Surface modification of PMMA polymer and its composites with PC61BM fullerene derivative using an atmospheric pressure microwave argon plasma sheet

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Andrzej Sikora ◽  
Dariusz Czylkowski ◽  
Bartosz Hrycak ◽  
Magdalena Moczała-Dusanowska ◽  
Marcin Łapiński ◽  
...  
Keyword(s):  
Contact Angle ◽  
Surface Modification ◽  
Chemical Composition ◽  
Water Contact Angle ◽  
Plasma Sheet ◽  
Atmospheric Pressure ◽  
Argon Plasma ◽  
Fullerene Derivative ◽  
Water Contact ◽  
Pmma Polymer

AbstractThis paper presents the results of experimental investigations of the plasma surface modification of a poly(methyl methacrylate) (PMMA) polymer and PMMA composites with a [6,6]-phenyl-C61-butyric acid methyl ester fullerene derivative (PC61BM). An atmospheric pressure microwave (2.45 GHz) argon plasma sheet was used. The experimental parameters were: an argon (Ar) flow rate (up to 20 NL/min), microwave power (up to 530 W), number of plasma scans (up to 3) and, the kind of treated material. In order to assess the plasma effect, the possible changes in the wettability, roughness, chemical composition, and mechanical properties of the plasma-treated samples’ surfaces were evaluated by water contact angle goniometry (WCA), atomic force microscopy (AFM), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). The best result concerning the water contact angle reduction was from 83° to 29.7° for the PMMA material. The ageing studies of the PMMA plasma-modified surface showed long term (100 h) improved wettability. As a result of plasma treating, changes in the samples surface roughness parameters were observed, however their dependence on the number of plasma scans is irregular. The ATR-FTIR spectra of the PMMA plasma-treated surfaces showed only slight changes in comparison with the spectra of an untreated sample. The more significant differences were demonstrated by XPS measurements indicating the surface chemical composition changes after plasma treatment and revealing the oxygen to carbon ratio increase from 0.1 to 0.4.

Surface Modification of Asymmetric Polysulfone Membrane by UV Irradiation

2014 ◽  
Vol 70 (2) ◽  
Author(s):  
Sutthisa Konruang ◽  
Thawat Chittrakarn ◽  
Suksawat Sirijarukul
Keyword(s):  
Contact Angle ◽  
Surface Modification ◽  
Functional Groups ◽  
Uv Irradiation ◽  
Water Flux ◽  
Inversion Method ◽  
Asymmetric Structure ◽  
Polysulfone Membrane ◽  
Polar Functional Groups ◽  
Polysulfone Membranes

The effects of ultraviolet (UV) irradiation for surface modification of hydrophobic asymmetric polysulfone membranes have been investigated. The asymmetric polysulfone (PSF) membranes were prepared by phase inversion method using 19%-25% of PSF in two solvents, viz. dimethylacetamide (DMF) and Acetone (Ac) collectively. The surface of asymmetric polysulfone membranes were modified by UV ray with 254 and 312 nm wavelength. Chemical and physical properties of the untreated and the treated membranes were characterized. Scanning electron microscope (SEM) was used to determine asymmetric structure of polysulfone membranes. Contact angle device was used to analyzed the effected of UV ray treatment on hydrophilicity of membranes surface. Polar functional groups introduced by UV irradiation were examined using FTIR. The water flux was measured under a pressure of 500 kPa to 2,500 kPa with a feed temperature of 25°C. It was shown that asymmetric polysulfone membranes were produced and the UV ray treatment significantly alters the hydrophilicity of membranes surface indicated by the reduction of water contact angle with increasing treatment time. The FTIR analysis showed the formations of polar functional groups such as hydroxyl and carbonyl groups. Consequently, the surface of asymmetric polysulfone membranes was changed from hydrophobic to hydrophilic by UV irradiation leading to the enhancement of the water flux.

Physico Chemical Characterization of Nanofibrous Poly(Ε-Caprolactone) Electrospun Templates for Cell Adhesion

MRS Advances ◽  
2017 ◽  
Vol 2 (49) ◽  
pp. 2689-2694
Author(s):  
Karla A. Gaspar-Ovalle ◽  
Juan V. Cauich-Rodriguez ◽  
Armando Encinas
Keyword(s):  
Mechanical Properties ◽  
Differential Scanning Calorimetry ◽  
Cell Adhesion ◽  
Tensile Modulus ◽  
Chemical Characterization ◽  
Mechanical Analysis ◽  
Scanning Calorimetry ◽  
Water Contact ◽  
Physico Chemical ◽  
Static Water

ABSTRACTNanofibrous mats of poly ε-caprolactone (PCL) were fabricated by electrospinning. The nanofiber structures were investigated and characterized by scanning electron microscope, differential scanning calorimetry, thermogravimetric analysis, dynamic mechanical analysis, static water-contact-angle analysis and mechanical properties. The results showed that the nanofibrous PCL is an ideal biopolymer for cell adhesion, owing to its biocompatibility, biodegradability, structural stability and mechanical properties. Differential scanning calorimetry results showed that the fibrous structure of PCL does not alter its crystallinity. Studies of the mechanical properties, wettability and degradability showed that the structure of the electrospun PCL improved the tensile modulus, tensile strength, wettability and biodegradability of the nanotemplates. To evaluate the nanofibrous structure of PCL on cell adhesion, osteoblasts cells were seeded on these templates. The results showed that both adhesion and proliferation of the cells is viable on these electrospun PCL membranes. Thus electrospinning is a relatively inexpensive and scalable manufacturing technique for submicron to nanometer diameter fibers, which can be of interest in the commodity industry.

scholarly journals Surface modification and adhesion improvement of polyester films

2013 ◽  
Vol 11 (1) ◽  
pp. 35-45 ◽  
Author(s):  
Aniello Cammarano ◽  
Giovanna Luca ◽  
Eugenio Amendola
Keyword(s):  
Free Energy ◽  
Surface Modification ◽  
Surface Free Energy ◽  
Self Assembly ◽  
Treatment Time ◽  
Solution Treatment ◽  
Film Surface ◽  
Critical Surface ◽  
Hydrolysis Time ◽  
Critical Surface Tension

AbstractFacile surface modification of polyester films was performed via chemical solutions treatment. Surface hydrolysis was carried out by means of sodium hydroxide solutions, leading to the formation of carboxylate groups. Three commercial polyester films of 100 μm in thickness were used in this work: AryLite™, Mylar™, and Teonex™, hydrolysis time being the main modification parameter. FTIR-ATR analysis, topography and contact angle (CA) measurements, surface free energy (SFE) and T-Peel adhesion tests were carried out to characterize the modified films. A quantitative estimate of the carboxylates surface coverage as a function of treatment time was obtained through a supramolecular approach, i.e. the ionic self-assembly of a tetracationic porphyrin chromophore onto the film surface. The surface free energy and critical surface tension of the hydrolyzed polyesters was evaluated by means of Zisman, Saito, Berthelot and Owens-Wendt methods. It was shown that NaOH solution treatment increases roughness, polarity and surface free energy of polymers. As a result, T-Peel strengths for modified Mylar™ and Teonex™ films were respectively 2.2 and 1.8 times higher than that for the unmodified films, whereas AryLite™ adhesion test failed.

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