Surface Properties Of Polyethylene Terephthalate Research Articles

Inkjet-printed plasma-functionalized polymer-based capacitive sensor for PAHs

The inkjet-printing technology is utilized to foster conducting layers, interconnections, and other features on different substrates of which its success greatly depends on the surface properties of the substrates. In the present work, we reported the use of low-temperature plasma (LTP) to assist in tailoring the surface properties of polyethylene terephthalate (PET). This facilitated the inkjet printing of a capacitive electrode sensor design using silver nano-ink (AgNI) for polycyclic aromatic hydrocarbons (PAHs). PAHs are ubiquitous environmental pollutants that are of great health concern. We have sifted methyl methacrylate (MMA), N-vinylpyrrolidone (VP), and oxygen (O2) as plasma fed-gases for improving the adhesion of printed AgNI on PET. We observed improved surface hydrophilicity of the plasma-treated PET (p-PET). This was evidenced by the decrease in water contact angle (WCA). The change in surface chemistry with plasma treatment was assessed using X-ray Photoelectron spectroscopy (XPS). Atomic Force Microscopy (AFM) was employed in determining the nanoscale surface roughness of PET. We then fabricated the capacitive sensor using AgNI to quantitatively sense the PAH from aqueous media. This sensor was subsequently characterized using Scanning Electron Microscopy (SEM) and Keyence 3D imaging. The capacitance values have shown a linear response with increased PAH concentration. The sensor design exhibits a high sensitivity for PAH concentrations up to 0.05 ng/mL. Ultimately, these results have demonstrated the potential of this polymer device for pollutant sensing applications.

Surface Properties of the Polyethylene Terephthalate (PET) Substrate Modified with the Phospholipid-Polypeptide-Antioxidant Films: Design of Functional Biocoatings.

Surface properties of polyethylene terephthalate (PET) coated with the ternary monolayers of the phospholipid 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), the immunosuppressant cyclosporine A (CsA), and the antioxidant lauryl gallate (LG) were examined. The films were deposited, by means of the Langmuir-Blodgett (LB) technique, on activated by air low temperature plasma PET plates (PETair). Their topography and surface chemistry were determined with the help of atomic force microscopy (AFM) and time-of-flight secondary ion mass spectrometry (TOF-SIMS), respectively, while wettability was evaluated by the contact angle measurements. Then, the surface free energy and its components were calculated from the Lifshitz-van der Waals/Acid-Base (LWAB) approach. The AFM imaging showed that the Langmuir monolayers were transferred effectively and yielded smoothing of the PETair surface. Mass spectrometry confirmed compatibility of the quantitative and qualitative compositions of the monolayers before and after the transfer onto the substrate. Moreover, the molecular arrangement in the LB films and possible mechanisms of DOPC-CsA-LG interactions were determined. The wettability studies provided information on the type and magnitude of the interactions that can occur between the biocoatings and the liquids imitating different environments. It was found that the changes from open to closed conformation of CsA molecules are driven by the hydrophobic environment ensured by the surrounding DOPC and LG molecules. This process is of significance to drug delivery where the CsA molecules can be released directly from the biomaterial surface by passive diffusion. The obtained results showed that the chosen techniques are complementary for the characterization of the molecular organization of multicomponent LB films at the polymer substrate as well as for designing biocompatible coatings with precisely defined wettability.

Atmospheric-pressure plasma assisted engineering of polymer surfaces: From high hydrophobicity to superhydrophilicity

To engineer polymer surfaces with long-lasting wettability properties and with high coating stability in aqueous media, we investigated the surface wettability of polyethylene terephthalate (PET) films treated by radio frequency (RF) atmospheric-pressure plasma. By combining plasma activation and hexamethyldisiloxane (HMDSO)-based plasma polymerization, stable PET surface properties from highly hydrophobic to superhydrophilic were achieved. The results clearly showed that the wettability of PET surfaces could be tuned from stable high hydrophobicity (>140°) to stable superhydrophilicity (<10°) with a minimized aging effect by using plasma activation of plasma deposited coatings. Surface roughness increase and CH3 groups introduction are primarily responsible for the coating hydrophobization, while the introduction of more oxygen-containing polar functional groups is the main factor leading to superhydrophilization. Importantly, the coatings engineered by this unique combination showed high stability in water over 14 days. Overall, this work contributes to the easy-to-overlook links between plasma activation and plasma polymerization, demonstrates that atmospheric-pressure RF plasma can be a versatile tool to control surface properties of polymers in a wide range from high hydrophobicity to superhydrophilicity with high coating stability in aqueous media and a negligible aging effect, which is promising for emerging biomedical applications.

Preparation and characterization of polyethylene terephthalate-chamomile oil blends with enhanced hydrophilicity and anticoagulant properties.

New blend films based on polyethylene terephthalate (PET) with different concentrations (50, 100 and 200 µL) of chamomile oil (CAO) were prepared. The effect of oil on the dielectric properties, structural and surface properties of PET was studied. The wettability of the blend films was evaluated by contact angle measurements. In vitro platelet adhesion on the surface and coagulation assessment were conducted to evaluate the behavior of the new blends for blood contact applications. Results of the study indicate that the wettability of PET-CAO blends up to 100 µL has been enhanced relative to the pure PET as indicated by the decrease in contact angle measurements. The attenuation total reflection-Fourier transform infrared spectra of the blends confirmed the presence of chamomile oil in the polymer matrix and suggested the presence of interaction between them. The permittivity ε' values decreased by increasing oil content upto 100 µL. On the other hand, the values of dielectric loss ε″ were found to increase by increasing oil content to 100 µL after which it decreased. The delay in partial thromboplastin time (PTT) of the blood would validate the anti-coagulant property of PET-CAO blends. The results demonstrated that the PET-CAO blends with concentration of 100 µL could be considered as a promising candidate material in blood contact application.

Tailoring surface properties of polyethylene terephthalate by atmospheric pressure plasma jet for grafting biomaterials

Tailoring surface hydrophilicity on polyethylene terephthalate (PET) by a radio frequency (RF) atmospheric pressure plasma jet (APPJ) for grafting biomaterials was investigated in this study. Two thermally responsive biomaterials of hydrophilic non-ionic surfactant of polyoxyethylene polymer and hydroxypropyl cellulose were used, while hydroxyethylmethacrylate (HEMA) was applied as the carrier for drug release. As applying the RF power in an APPJ system, PET substrates represented a tendency from an originally hydrophobic surface to a hydrophilic one, while apparent damaged areas were observed as the RF power exceeded 200 W. APPJ-induced polar functional groups onto PET surface without serious etching were most likely to improve the surface hydrophilicity for further grafting biomaterials. The grafted polyoxyethylene polymer on APPJ-treated PET substrates exhibited a surface change from opaque into transparent as the ambient temperature exceeded lower critical solution temperature of 37°C, while hydroxypropyl cellulose displayed a change from transparent into milky white as the temperature over 55°C. For the drug release behavior of aspirin on APPJ-treated PET substrates, the cumulative release rate of aspirin entrapped substrate for 3 h was 22%. Our results suggest that tailoring surface hydrophilicity of PET substrates without surface etching by 100W-APPJ process possessed a higher surface energy with a higher polar interaction, resulting in a good bonding with the grafted biomaterials.

Effect of Microwave Treatment on Biophysical and Surface Properties of Polyethylene Terephthalate (PET) for Blood Contact Applications

The microwave radiation with different powers (0, 180, 360, 540 and 720 W) was investigated as a low-cost and easily processing technique for surface modification of polyethylene terephthalate (PET). Dielectric measurements and Fourier transform infrared spectroscopy (FTIR) were used to study the changes in the structural properties of PET. Contact angle was measured to indicate the wettability. Monitoring of the platelets adhesion on the surface of the samples was studied by scanning electron microscopy (SEM) using platelet adhesion test in addition to hematological tests. Results revealed that the contact angle decreased by increasing the MW power, demonstrating an increase in wettability of the samples. By increasing the microwave power, values of dielectric constant e′ and dielectric loss e″ decreased in addition to decrease in the value of electrical conductivity σ. The relaxation times τ2 and τ3 associated with the second and third regions describe the movement of the side chains and the attached groups, respectively, decreased by increasing the power of MW. This decrease reflects degradation of these chains due to the application of MW. SEM images show much less platelet adhesion on the surface of the treated samples as compared to the untreated ones. Prothrombin time (PT), partial thromboplastin time (PTT) and international normalized ratio (INR) have been prolonged after MW treatment and were comparable with the control blood values. Results of FTIR indicate that the degradation of the polymer becomes dominant after 360 W. The samples subjected to MW treatment with 360 W were found to have the most acceptable properties for blood contact applications.

Endothelialization of Polyethylene Terephthalate Treated in SO2 Plasma Determined by the Degree of Material Cytotoxicity

Improving the biocompatibility of polyethylene terephthalate (PET) vascular grafts is an important task for avoiding thrombus formation. Therefore, SO2 plasma at various treatment periods were used to modify PET surface properties by forming sulfate functional groups. These groups were shown to act antithrombogenically, ensuring good hemocompatibility of the materials, although the biocompatibility of such materials still remains a mystery. For this reason, the adhesion and viability of HUVEC cells on SO2 plasma-modified PET surfaces were studied, and the possible toxicity of the tested material was determined using two different assays, MTT (metabolic activity assay) and SRB (in-vitro toxicology assay). Changes in chemical composition, morphology and wettability were determined as well. Improved endothelialization was observed for all plasma-treated samples, with the most optimal being the sample treated for 80 s, which can be explained by it having the best combination of surface functionalization, roughness and morphology. Furthermore, toxicity was observed to some extent on the sample treated for 160 s, indicating the lowest cell density among the plasma-treated samples. X-ray photoelectron spectroscopy showed increased oxygen and sulfur content on the surface, which was independent on treatment time. Surface roughness of the plasma-treated samples increased, reaching its maximum after 80 s of treatment, and decreased thereafter.

Plasma treated polyethylene terephthalate for increased embedment of UV-responsive microcapsules

Polyethylene terephthalate (PET) fabric was treated in a late afterglow of plasma created by a microwave (MW) discharge in the surfatron mode, by using oxygen (O2) and ammonia (NH3) gases. The series of treatments using one gas or the combination of both at different treatment times were performed in order to increase the embedment of UV-responsive microcapsules that were deposited onto PET with pad-dry-cure process. Plasma in both gases was characterized by optical emission spectroscopy (OES), which showed substantial dissociation of O2 and NH3 molecules as well as formation of NHx radicals due to the partial dissociation of ammonia molecules. The chemically active species in the plasma afterglow changed the surface properties of PET that were analysed using X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF–SIMS), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and water absorption analysis. The effectiveness of plasma treatment on embedment of UV-responsive microcapsules on PET was evaluated by UV-responsiveness, colour strength and colour depth using reflectance spectroscopy, add-on and air permeability, respectively. Treating PET by O2 afterglow followed by a longer treatment by NH3 afterglow increased the polymers hydrophilicity and concentration of nitrogen-rich functional groups on surface that enabled higher uptake of UV-responsive microcapsules, and consequently better responsiveness of fabric to UV radiation. The add-on of microcapsules was almost 8-times higher and the colour depth increased up to 75% for plasma treated samples.

Ambient air plasma pre‐treatment of non‐woven fabrics for deposition of antibacterial poly (l‐lactide) nanoparticles

Production of medical dressings specific to infected wounds remains one of the great challenges in medicine. In this paper, an integrated application that allows the immobilization of poly(l‐lactide) (PLLA) nanoparticles (NPs) containing the antimicrobial agent octenidine on non‐woven fabrics (NWs) is investigated. Non‐thermal plasma generated by atmospheric pressure diffuse coplanar surface barrier discharge (DCSBD) was used for activation, modification, and improvement of the surface properties of polyethylene terephthalate (PET) and polypropylene (PP) NWs. The DCSBD system was integrated into a roll‐to‐roll production setup that prepared NWs for deposition of NPs using purpose‐adapted inkjet printing equipment. The surface properties of the plasma‐treated polymers were examined by means of strike‐through time (SST) measurements and X‐ray photoelectron spectroscopy. The plasma modification of PET and PP NWs improved NP distribution and enabled uniform diffusion over polymer surfaces. The SST measurements indicate improvements in the hydrophilicity and permeability of plasma‐treated PET and PP fabrics by reducing strike‐through time from 400 s (for untreated polymers) to 6 s. This continuous method of delivering NPs onto plasma‐pretreated polymer surfaces has the potential to be adapted to impregnated dressing production, with considerable benefits in terms of cheapness, convenience, speed, and full automation.

Scanning-probe-microscopy of polyethylene terephthalate surface treatment by argon ion beam

The effect of argon (Ar+) ion beam treatment on the surface of polyethylene terephthalate (PET) samples was studied by scanning probe microscopy (SPM) and the changes in surface topography were assessed by atomic force microscopy (AFM). Kelvin probe force microscopy (KPFM) sheds light of adhesion force between treated polymer films and a Pt/Cr probe under dry conditions, obtaining the contact potential difference of material. As a result of Ar+ ion bombardment, important surface chemical changes were detected by X-ray photoelectron spectroscopy (XPS) measurements such as chains scission and incorporation of nitrogen species. Ion beam treatment increases the surface roughness from 0.49±0.1nm to 7.2±0.1nm and modify the surface potential of PET samples, decreasing the adhesive forces from 12.041±2.1nN to 5.782±0.06nN, and producing a slight increase in the electronic work function (Φe) from 5.1V (untreated) to 5.2V (treated). Ar+ ion beam treatment allows to potentially changing the surface properties of PET, modifying surface adhesion, improving surface chemical changes, wetting properties and surface potential of polymers.

Activation of PET Using an RF Atmospheric Plasma System

The plasma treatment of polymer surfaces is routinely used to enhance surface properties prior to adhesive bonding or biomolecule interaction. This study investigates the influence of plasma treatment conditions on the surface activation of polyethylene terephthalate (PET) using the SurFx Atomflo™ 400L plasma source. In this study the effect of applied plasma power, processing speed, gas composition and plasma applicator nozzle to substrate distance were examined. The level of polymer surface activation was evaluated based on changes to the water contact angle (WCA) of PET samples after plasma treatment. PET surface properties were also monitored using surface energy and X-ray photoelectron spectroscopy (XPS) analysis. The heating effect of the plasma was monitored using thermal imaging and optical emission spectroscopy (OES) techniques. OES was also used as a diagnostic tool to monitor the change in atomic and molecular species intensity with changes in experimental conditions in both time and space. XPS analysis of the PET samples treated at different plasma powers indicated that increased oxygen content on samples surfaces accounted for the decreases observed in WCAs. For the first time a direct correlation was obtained between polymer WCA changes and the OES measurement of the atomic hydrogen Balmer Hα and molecular OH line emission intensities.

The influence of N ion bombardment on the properties of PET surface and SiN x/PET complex

The surfaces of polyethylene terephthalate (PET) substrates were bombarded by N ions at room temperature. Varying the working power of ion source, PET surfaces with different composition and properties were obtained. Characterization by X-ray photoelectron spectrometry showed that the ester bonds at PET surface, especially C–O bonds, were selectively destroyed. With increasing the working power of ion source, more N element chemically bonded with C and formed C–N bonds. But such change only happened at the PET surface and the influence depth was less than 5 nm. The contact angle results revealed that with increasing the working power of ion source, the static contact angle of PET surface to pure water increased from 51° to 95°. With these results, one conclusion could be deduced that the surface properties of PET could be influenced by the relative content of N element chemically bonded at surface, which in turn was controlled by the working power of ion source. Finally, the bombarded PET substrates were coated with same silicon nitride (SiN x) film. The static contact angle of SiN x/PET complex with PET surface bombarded with 150 W, displayed no obvious difference before and after the bending fatigue test, which was caused by the little difference in surface morphology before and after test. Combining the results of the static contact angle and surface morphology, PET surface bombarded with 150 W displayed better crosslink properties to form SiN x/PET complex.

Effect of humid air exposure between successive helium plasma treatments on PET foils

It is well known that helium plasmas can successfully alter the surface properties of polyethylene terephthalate (PET). However, the influence of humid (atmospheric) air exposure between successive helium plasma treatment steps has not been previously examined. In this work, PET foils are treated in successive short treatment steps of 5s with a DBD operating in helium at medium pressure (5.0kPa). Between every plasma treatment step, the samples are either kept in the plasma chamber at 5.0kPa under helium atmosphere or are exposed to humid air at atmospheric pressure. The plasma-treated samples are examined using contact angle measurements and X-ray photoelectron spectroscopy (XPS). Results clearly show that exposure to humid air between successive helium plasma treatment steps leads to a larger decrease in water contact angle and a more pronounced oxygen incorporation. XPS results have shown that during each helium plasma treatment, O–C═O groups are introduced on the PET surfaces. However, when the samples are exposed to humid air between plasma treatments, also C–O groups are created on the PET surfaces. These C–O groups are mainly introduced during exposure to humid air: every helium plasma treatment creates surface radicals, which can in turn react with oxygen species present in the atmosphere during subsequent humid air exposure, leading to the incorporation of C–O groups.

The effect of working pressure on the chemical bond structure and hydrophobic properties of PET surface treated by N ion beams bombardment

Polyethylene terephthalate (PET) surface was bombarded by N ion beams at room temperature. Varying the working pressure of the ion beams, PET surfaces with different composition and properties were obtained. Characterization by X-ray photoelectron spectrometry showed that only on film surface, ester bonds, especially C–O bonds, were broken and N element chemical bonded with C. The influence depth was less than 5 nm because of the lower ion energy (about 10 3 eV). Contact angle results revealed that with increasing the working pressure of ion beams, the contact angle of PET surface to pure water increased from 51° to 130°. With these results, one conclusion could be deduced that the hydrophilic and hydrophobic properties of PET surface could be influenced by N atom chemical bond with C, which in turn is controlled by the working pressure of N ion beams.

Effects of operating parameters on DC glow discharge plasma induced PET film surface

A DC glow discharge plasma surface modification techniques are used to modify surface properties of polymeric materials such as adhesivity, hydrophobicity, hydrophilicity and biocompatibility. The plasma interaction with the surface produces modifications of its chemical structure and morphology. The objective of this study is to examine the effect of operating parameters such as discharge potential, pressure and exposure time on surface properties of polyethylene terephthalate (PET) film. The changes in hydrophilic properties of PET films were studied in detail using contact angle and surface energy measurements. The surface morphology and chemical composition of plasma modified film surfaces were studied by atomic force microscopy (AFM) and X-ray photo electron spectroscopy (XPS). It was found that the efficiency of the surface treatment increases with increasing discharge potential, pressure and exposure time. The AFM and XPS analysis showed changes in surface topography and formation of polar groups on the plasma modified PET surfaces.

Contact angle analysis of low-temperature cyclonic atmospheric pressure plasma modified polyethylene terephthalate

Polyethylene terephthalate (PET) films are modified by cyclonic atmospheric pressure plasma. The experimentally measured gas phase temperature was around 30 °C to 90 °C, indicating that this cyclonic atmospheric pressure plasma can treat polymers without unfavorable thermal effects. The surface properties of cyclonic atmospheric pressure plasma-treated PET films were examined by the static contact angle measurements. The influences of plasma conditions such as treatment time, plasma power, nozzle distance, and gas flow rate on the PET surface properties were studied. It was found that such cyclonic atmospheric pressure plasma is very effective in PET surface modification, the reduced water contact angle was observed from 74° to less than 37° with only 10 s plasma treatment. The chemical composition of the PET films was analyzed by X-ray photoelectron spectroscopy (XPS). Atomic force microscopy (AFM) was used to study the changes in PET surface feature of the polymer surfaces due to plasma treatment. The photoemission plasma species in the continuous cyclone atmospheric pressure plasma was identified by optical emission spectroscopy (OES). From OES analysis, the plasma modification efficiency can be attributed to the interaction of oxygen-based plasma species in the plasma with PET surface. In this study, it shows a novel way for large scale polymeric surface modification by continuous cyclone atmospheric pressure plasma processing.

Enzymatic surface modification and functionalization of PET: A water contact angle, FTIR, and fluorescence spectroscopy study

The purpose of this study was to investigate the changes induced by a lypolytic enzyme on the surface properties of polyethylene terephthalate (PET). Changes in surface hydrophilicity were monitored by means of water contact angle (WCA) measurements. Fourier Transform Infrared spectroscopy (FTIR) in the Attenuated Total Reflectance mode (ATR) was used to investigate the structural and conformational changes of the ethylene glycol and benzene moieties of PET. Amorphous and crystalline PET membranes were used as substrate. The lipolytic enzyme displayed higher hydrolytic activity towards the amorphous PET substrate, as demonstrated by the decrease of the WCA values. Minor changes were observed on the crystalline PET membrane. The effect of enzyme adhesion was addressed by applying a protease after-treatment which was able to remove the residual enzyme protein adhering to the surface of PET, as demonstrated by the behavior of WCA values. Significant spectral changes were observed by FTIR-ATR analysis in the spectral regions characteristic of the crystalline and amorphous PET domains. The intensity of the crystalline marker bands increased while that of the amorphous ones decreased. Accordingly, the crystallinity indexes calculated as band intensity ratios (1,341/1,410 cm(-1) and 1,120/1,100 cm(-1)) increased. Finally, the free carboxyl groups formed at the surface of PET by enzyme hydrolysis were esterified with a fluorescent alkyl bromide, 2-(bromomethyl)naphthalene (BrNP). WCA measurements confirmed that the reaction proceeded effectively. The fluorescence results indicate that the enzymatically treated PET films are more reactive towards BrNP. FTIR analysis showed that the surface of BrNP-modified PET acquired a more crystalline character.

The biomedical properties of polyethylene terephthalate surface modified by silver ion implantation

Polyethylene terephthalate (PET) film is modified by Ag ion implantation with a fluence 1×1016ions/cm2. The results of X-Ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) indicate that silver has been successfully implanted into the surface of PET. The PET samples modified by silver ion implantation have significantly bactericidal property. The capacity of the staphylococcus epidermidis (SE) adhered on the Ag+ implanted PET surface is 5.3×106CFU/ml, but the capacity of the SE adhered on the untreated PET film is 2.23×107CFU/ml. The thromboembolic property is evaluated by in vitro platelet adhesion test, and there is not statistically difference between the untreated PET and the Ag+ implanted PET for the number of adhered and activated platelets. The PET implanted by silver ion has not acute toxicity to endothelial cell (EC) which was evaluated by the release of lactate dehydrogenase (LDH) test.

Uniformity analysis of dielectric barrier discharge (DBD) processed polyethylene terephthalate (PET) surface

A dielectric barrier discharge (DBD) plasma, operating in air at atmospheric pressure, has been used to induce changes in the surface properties of polyethylene terephthalate (PET) films. The effects that the key DBD operating parameters: discharge power, processing speed, processing duration, and electrode configurations, have on producing wettability changes in the PET surface region have been investigated. The approach taken involves the application of an Taguchi experimental design and robust analysis methodology. The various data sets obtained from these analyses have been used to studies the effect of the operating parameters on the surface uniformity and efficiency of the said treatment. In general, the results obtained indicate that DBD plasma processing is an effective method for the controlled surface modification of PET. Relatively short exposures to the atmospheric pressure discharge produces significant wettability changes at the polymer film surface, as indicted by pronounced reductions in the water contact angle measured. It was observed that the wettability of the resultant surface shows no significant differences in respect to orientation parallel (L-direction) or perpendicular (T-direction) to the electrode long axis. However, there was significant differences between the data obtained from these two orientations. Analysis of the role of each of the operating parameters concerned shows that they have a selective effectiveness with respect to resultant surface modification in terms of uniformity of modification and wettability. The number of treatment cycles and the electrode configuration used were found to have the most significant effects on the homogeneity of the resultant PET surface changes in L- and T-orientation, respectively. On the other hand, the applied power showed no significant role in this regard. The number of treatment cycles was found to be the dominant factor (at significance level of 0.05) in respect of water contact angle changes at the processed PET surface in both orientations. The driven metal electrodes (stainless steel or aluminium) were apparently superior to the driven dielectric electrode (ceramic or quartz) configurations. The grounded electrode in each case was a silicon rubber-covered aluminium plate (see later). The nature and scale of the surface changes that originate from the various processing conditions employed have been considered so as to determine the optimum treatment conditions in respect of processing outcomes, properties and any orientation dependence. Thus, it was revealed that higher processing speeds and longer processing durations are key for uniformity along the electrode axial orientation, while lower processing speeds and short exposure durations are key considerations, in the corresponding perpendicular orientation. In general, longer processing durations (low processing speeds and a high number of treatment cycles) and higher plasma powers induced greater changes in the surface wettability of the PET, as demonstrated by the observed water contact angles. This behaviour is taken to indicate that different combinations of DBD operating parameters and electrodes produce discharge conditions that can result in different plasma chemical processes in respect of uniformity, treatment efficiency and orientation dependence.

Surface Treatment of Polyethylene Terephthalate Film Using Atmospheric Pressure Glow Discharge in Air

Non-thermal plasmas under atmospheric pressure are of great interest in polymer surface processing because of their convenience, effectiveness and low cost. In this paper, the treatment of Polyethylene terephthalate (PET) film surface for improving hydrophilicity using the non-thermal plasma generated by atmospheric pressure glow discharge (APGD) in air is conducted. The discharge characteristics of APGD are shown by measurement of their electrical discharge parameters and observation of light-emission phenomena, and the surface properties of PET before and after the APGD treatment are studied using contact angle measurement, x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). It is found that the APGD is homogeneous and stable in the whole gas gap, which differs from the commonly filamentary dielectric barrier discharge (DBD). A short time (several seconds) APGD treatment can modify the surface characteristics of PET film markedly and uniformly. After 10 s APGD treatment, the surface oxygen content of PET surface increases to 39%, and the water contact angle decreases to 19°, respectively.