We discuss in this review how the roughness of a solid impacts its wettability. We see in particular that both the apparent contact angle and the contact angle hysteresis can be dramatically affected by the presence of roughness. Owing to the development of refined methods for setting very well-controlled micro- or nanotextures on a solid, these effects are being exploited to induce novel wetting properties, such as spontaneous filmification, superhydrophobicity, superoleophobicity, and interfacial slip, that could not be achieved without roughness.

Polyethylene terephthalate (PET) plates have been exposed to different nitrogen containing plasmas with the purpose of incorporating nitrogen functional groups on its surface. Results with a dielectric barrier discharge (DBD) at atmospheric pressure and a microwave discharge (MW) at reduced pressure and those using an atom source working under ultrahigh vacuum conditions have been compared for N₂ and mixtures Ar + NH₃ as plasma gases. The functional groups have been monitored by X-ray Photoemission Spectroscopy (XPS). Nondestructive oxygen and carbon depth profiles for the plasma treated and one month aged samples have been determined by means of the nondestructive Tougaard’s method of XPS background analysis. The surface topography of the treated samples has been examined by Atomic Force Microscopy (AFM), while the surface tension has been determined by measuring the static contact angles of water and iodomethane. It has been found that the DBD with a mixture of Ar+NH₃ is the most efficient treatment for nitrogen and amine group functionalization as determined by derivatization by reaction with chlorobenzaldehyde. It is also realized that the nitrogen functional groups do not contribute significantly to the observed increase in surface tension of plasma treated PET.

Physical and chemical surface modifications of polyethyleneterephthalate (PET) films due to treatment with excimer UV lamps (222 nm) have been studied. Interpretations of the reactions and products were made in comparison to known PET irradiations with excimer UV lasers and broad-band UV sources. In this context the advantages of the excimer UV lamps as a light source, i.e., a quasi monochromatic radiation source with a power density which is sufficient for initiating surface reactions without changing the topography of the substrate, have been shown. Analytical data on treated PET to characterize the surface modifications were obtained by contact-angle measurements, dyeing with cationic dyestuff, scanning electron microscopy (SEM), photoacoustic Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) studies. With regard to possible industrial applications, the relevance for textile finishing and some perspectives for future developments are pointed out.

This paper aims to provide an analysis of the correlation between various plasma effects on polymers exposed to atmospheric pressure plasma. The relationship linking the surface polarity, the chemical structure and composition and the crystalline/amorphous phase contribution in the surface modification mechanisms of plasma-exposed polymers is explored. Different polymers were chosen comprising of various structures, functionality, degree of oxidation, crystallinity, and were treated under a particular experimental configuration, and dielectric barrier discharge-type. The plasma parameters and the treatment settings are observed, in relation to relevant surface properties, as surface energy components, surface topography, structural changes and chemical composition, under conditions where the gaseous environment chosen, He-N₂, allows complex surface modification, by combined functionalisation and crosslinking.

The recently observed enhancement in adhesion between Cu and Teflon due to a presputtering treatment of Teflon prior to the Cu deposition is analyzed. The sputtering treatment resulted in a morphology change of the Teflon, with the deposited Cu showing similar textures, and changes in chemical bondings between the two. A simple geometric model is used to analyze the contribution from the morphology changes to the observed peel strength. It is shown that, for a finite chemical bonding, an appreciable contribution to the peel strength is possible from the morphology changes observed.

Atmospheric pressure plasma treatment of the surface of a polypropylene film can significantly increase its surface energy and, thereby improve the printability of the film. A laboratory-scale dielectric barrier discharge (DBD) system has therefore been developed, which simulates the electrode configuration and reel-to-reel web transport mechanism used in a typical industrial-scale system. By treating the polypropylene in a nitrogen discharge, we have shown that the water contact angle could be reduced by as much as 40° compared to the untreated film, corresponding to an increase in surface energy of 14 mNm⁻¹. Ink pull-off tests showed that the DBD plasma treatment resulted in excellent adhesion of solvent-based inks to the polypropylene film.

Pyrene time-resolved fluorescence has been applied to correlate the surface tension levels obtained for polyethylene and polypropylene films after exposure to corona-discharge treatment. The surface tension level of the films was validated with surface tension test fluids according to the ASTM D2578 standard test method. Although in direct contact with air, pyrene showed an extremely long lifetime upon deposition on the polymer films, which approached the lifetime of pyrene in freeze/pump/thaw deoxygenated hexane. The I/III ratio of pyrene fluorescence at 373 and 384 nm, designated as bands I and III, was determined at 150-ns delay relative to the time at laser maximum. Prolonged time delay was imposed before fluorescence measurement in order to minimize the background interferences from the blank films. Measurements of the time-resolved pyrene fluorescence I/III ratio from pyrene/ethanol depositions showed averages of 0.63, 0.56, and 0.49 for 42, 35, and 30 dyne/cm treated films. The uncertainty of the measurements was estimated to be 1–2 dyne/cm. Application of the pyrene I/III ratio can be used easily to monitor incorrectly and nonuniformly treated polymer film surfaces.

The effect of gamma-radiation on the surface chemical properties of polystyrene was studied by ESCA and FT-IR. Gamma-radiation produces surface >CO and CO containing functional groups only, and also causes oxidation to depths >10 nm as detected by ESCA. FT-IR spectra showed that below the top few molecular layers ester, acid, and carbonyl groups of various types were present. The α,β-unsaturated carbonyl/acid groups form a higher proportion of the total carbonyls with increasing depth. Surface oxidation follows pseudo-first-order kinetics; the extent of interior oxidation is linear with dose.

Some results are presented concerning the laser-induced photochemical enhancement of the adhesive bonding strength between polypropylene (PP) and adhesives on a resinous basis. The mechanism of the laser-activated processes is discussed. At some conditions a bonding strength enhancement of more than 5 times has been achieved.

X-ray photoelectron spectroscopy is used to measure the surface composition of polycarbonate/ poly(butylene terephthalate) blends. The blend surface is enriched in PC compared to the bulk, with the surface PC/PBT ratio equal to about 1.6 times to bulk formation. For blends containing an impact modifier as a third component, the XPS spectra of the molded surface indicates that no impact modifier is present within the XPS sampling depth. A spectral simulation scheme improves the accuracy of the computed PC/PBT ratio over conventional data reduction schemes involving curve fitting.

XPS, SSIMS, water contact angle and each rate measurements have been used to characterize the effect of CF₄/O₂ discharges on bisphenol-A-polycarbonate (PC). 1% O₂ discharges resulted in the grafting of fluorocarbon radicals to the polymer surface. At higher O₂ percentage in the gas feed fluorine atoms reacted with the polymer surface inducing degradation of the aromatic rings and etching. Oxidation of the PC surface was observed after all the treatments. Due to considerations based on reactivity and relative concentration in the discharge, oxygen molecules are considered more effective than oxygen atoms in inducing oxidation. Etching was found to occur as well; fluorine atoms and oxygen molecules are considered most important in promoting it.

SSIMS (static secondary ion mass spectroscopy) has been used to aid in the interpretation of hydrophobic recovery of oxygen plasma treated PS (polystyrene), together with XPS (X-ray photoelectron spectroscopy) and water contact angle measurements.

The heterogeneity in sputter yields of different ions did not allow complete qualitative and quantititative information to be obtained. Yet negative ion spectra of surfaces treated with plasmas of isotopically enriched oxygen allowed us to follow closely the disappearance of polar groups during hydrophobic recovery. Furthermore, using isotopically enriched PS samples, it was possible to obtain unambiguous information about molecular weight and temperature-induced changes in the hydrophobic recovery mechanism, which could not have been provided by XPS.

In this paper, we report and discuss the results of the surface treatment, using an atmospheric pressure dielectric barrier discharge (DBD), of selected polymer films which have no bonded oxygen in their intrinsic structures. Contact angle, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) data are presented with respect to post-treatment characterisation and the dependence of these outcomes on the salient processing variables: energy dissipated, exposure duration and inter-electrode gap. Under the treatment conditions used, remarkably uniform treatment and markedly stable modified surface properties result from the test surfaces exposed to the discharge, even at transit speeds simulating those associated with continuous on-line processing. The DBD system thus described, provides chemically mild and mechanically non-destructive means of altering surface properties, targeting improved surface characteristics and potentially better application performance.

The interaction between a low-pressure gas plasma and organic materials has mechanical (surface cleaning and dry micro-etching) and electrostatic (cross-linking and surface activation) effects. Corrosion of a fluorinated ethylenepropylene (FEP) sample was studied for different conditions. The corrosion rate of FEP depends on the gas and on the gas pressure and has the highest value for oxygen. The modifications of the sample surface were studied by contact-angle measurements for water and formamide and by the thermally stimulated discharge current method. The optimum parameters for a continuum vacuum metallization process of FEP are presented.

The modifications induced by excimer laser radiation on different types of polymer surfaces (polyether-etherketone (PEEK), polycarbonate (PC) and epoxy resin) performed at laser fluences below the material ablation threshold have been investigated. Particular attention was given to the role of laser irradiation wavelength (193 or 248 nm) on the nature and properties of the treated surfaces. Results indicate that a much stronger reactivity was obtained after treatments at 193 nm for all the investigated polymers. At this wavelength, the original polymer surfaces are strongly modified by UV photons; surface reorganization occurs and polar groups induce an increase in the surface wettability.

In this paper, we report and discuss the results of the surface treatment, using an atmospheric pressure dielectric barrier discharge (DBD), of selected polymer films which have no bonded oxygen in their intrinsic structures. Contact angle, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) data are presented with respect to post-treatment characterisation and the dependence of these outcomes on the salient processing variables: energy dissipated, exposure duration and inter-electrode gap. Under the treatment conditions used, remarkably uniform treatment and markedly stable modified surface properties result from the test surfaces exposed to the discharge, even at transit speeds simulating those associated with continuous on-line processing. The DBD system thus described, provides chemically mild and mechanically non-destructive means of altering surface properties, targeting improved surface characteristics and potentially better application performance.

Modification of the surface properties of a polypropylene (PP) film using an air dielectric barrier discharge has been studied using atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and contact angle measurement. The atmospheric pressure air discharge is found to modify the PP surface in both morphology and composition, as expressed in the following outcomes: the spherulitic features of the surface of the pristine PP film change into randomly-shaped surface protrusions, with the surface roughness increasing as the processing time is extended; heavily oxidized carbon species are found on the plasma-processed surface and the contact angle is also reduced dramatically from 93.7° for the untreated surface to 53.8° post-treatment. After long-term storage in ambient air, the much lowered surface contact angle of the processed PP film is found to in part recover. Effective plasma-induced chemical etching appears to equilibrate after 25% of the surface carbon is oxidized. The CH₃ functionalities in the PP are believed to be oxidized preferentially by the air discharge plasma.

This paper concerns the use of the low-pressure plasma process to confer an hydrophobic character to poly(acrylonitrile) films, without altering their bulk properties. Plasma based fluorination processes using saturated fluorine compounds such as CF₄, C₆F₁₄ and mixtures CF₄/H₂ were used. Such treated polyacrylonitrile films were characterized by XPS analysis, infrared (ATR) spectroscopy and contact angle measurements. The use of CF₄ led to the fluorination of the film surfaces. Indeed, XPS spectra showed the presence of -CHF-, -CF₂- and -CF₃ groups. Moreover, the contact angle θ which was 63° for untreated PAN films increased to 115°. Fluorine incorporation in the PAN disappeared when hydrogen is added to CF₄. In the case of treatment by C₆F₁₄, fluorination was accompanied by a polymerization, as evidenced by XPS with the disappearance of the N 1s photopeak corresponding to the C≡N functions in PAN. By considering the deposition of F- containing layer thickness, it was possible in this latter case to follow the surface modifications by ATR-i.r. spectroscopy

Surface properties of a Melinex 800 PET polymer material modified by an atmospheric-pressure air dielectric barrier discharge (DBD) have been studied using X-ray photoelectron microscopy (XPS) and contact angle measurement. The results show that the material surface treated by the DBD was modified significantly in chemical composition, with the highly oxidised carbon species increasing as the surface processing proceeds. The surface hydrophilicity was dramatically improved after the treatment, with the surface contact angle reduced from 81.8° for the as-supplied sample to lower than 50° after treatment. Post-treatment recovery effect is found after the treated samples were stored in air for a long period of time, with the ultimate contact angles, as measured, being stabilised in the range 58–69° after the storage, varying with the DBD-treatment power density. A great amount of the C–O type bonding formed during the DBD treatment was found to be converted into the CO type during post-treatment storage. A possible mechanism for this bond conversion has been suggested.

In this paper, a dielectric barrier discharge operating in nitrogen at atmospheric pressure has been used to improve the surface hydrophilic property of polypropylene (PP) non-woven fabric. The changes in the hydrophilic property of the modified PP samples are investigated by the contact angle measurements and the variation of water contact angle is obtained as a function of the energy density; micrographs of the PP before and after plasma treatment are observed by scanning electron microscopy (SEM) and the chemical composition of the PP surface before and after plasma treatment is also analyzed by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The results show that the surface hydrophilic property of the PP samples is greatly improved with plasma treatment for a few seconds, as evidenced by the fact that the contact angle of the treated PP samples significantly decreases after plasma treatment. The analysis of SEM shows that the surface roughness of the treated PP samples increases due to bonding and etching in plasma processing. The analyses of FTIR and the C1s peak in the high-resolution XPS indicate that oxygen-containing and nitrogen-containing polar functional groups are introduced into PP surface in plasma processing. It can be concluded that the surface hydrophilic property of the modified PP samples has been obviously improved due to the introduction of oxygen-containing and nitrogen-containing polar groups and the increase of the surface roughness on the PP surface.

Ar plasma etched and Al metallised bisphenol A carbonate was analysed by mass spectroscopy, photoelectron spectroscopy (XPS), and scanning force microscopy (SFM). We mainly used a technical polymer (Makrolon 2808, Bayer) made by injection-moulding, as well as spin coated bisphenol A carbonate (n=1) and polycarbonate (PC) (n=115). The mass spectroscopy during the etching process shows the degradation of the PC in the form of carbon monoxide, carbon dioxide and methyl groups. The photoelectron spectroscopy shows in detail the surface modification after Ar plasma treatment and metallisation. The plasma induces a reduction of the carboxylic carbon (C 1s), a strong reduction of singly bonded oxygen (O 1s) and also a slight reduction of doubly bonded oxygen. After Al metallisation, a reaction of Al with the oxygen groups and an interaction with the aromatic system is documented. Ar plasma etching increases the chemical interaction of Al mainly with the aromatic carbon. The X-ray photoelectron spectroscopy of metallised PC under different initial conditions shows a strong influence of incorporated water in the PC bulk that cannot be seen by XPS on uncoated PC. The O 1s signal increases during metallisation and results in an oxidation of Al probably caused by the fact that the hydrophobic surfaces becomes hydrophillic. Temperature-dependent XPS was done on technical PC samples and on spin coated samples (n=1, n=115) and supports the influence of the bulk state for the Al–PC interface. For n=1 carbonate, a diffusion of Al into the PC volume was observed. The SFM measurements showed a roughening effect on the nanometer scale even after short treatment times. Al can be seen as a weakly bound cluster on the virgin PC, and if a pre-etching is done, Al seems to grow as a good wetting film. The adhesion force of Al films on PC without any influence of the volume can be explained by the chemical bonding of Al to the carboxylic and aromatic systems. The adhesion can be increased by plasma pre-treatment. A breakdown of the adhesion on technical PC is probably induced by a reaction of Al with mobile intercalated gas, that is enriched near the surface after Al coating.

The article describes applications of a novel windowless argon excimer source for surface modification. Experimental results on etching of polymeric surfaces, degradation of organic surface residues, surface activation and modification of gas permeability and selectivity of polymeric membranes are presented. Moreover, radical formation from the excimer source and surface curing of liquid acrylates are examined. Typical treatment times are in the range of minutes for photolytic decomposition effects and seconds for UV curing effects. The surface modification effects induced by the argon excimer source were analysed by XPS, ESR, IR-spectroscopy, white light reflection spectroscopy, scanning electron microscopy, micro-hardness and permeation measurements.

Laser-induced surface modification of different polymers is presented as a suitable pretreatment of surfaces in a two-step metallization process. Materials such as polyamide (PA), polypropylene (PP), polystyrene (PS), polycarbonate (PC), acrylbutadienestyrene (ABS), styreneacrylnitrile (SAN), polybutadieneterephthalate (PBT), and polyoxymethylene (POM) were treated by excimer-laser radiation at 248 nm in air. The aim of this study is to investigate different processing regimes of surface modification and ablation to increase surface roughness. Therefore, the laser-processing variables fluence F, repetition rate v and pulse number N are varied and the ablation depth, optical penetration depth, absorption coefficient and ablation threshold are determined. The metallization of pretreated (laser, wet chemical and plasma etching) polymers is investigated for different surface morphologies. The used metallization processes were electroplating and physical vapour deposition (PVD). The adhesion of the deposited films is measured with scratch and tape test methods in order to determine the regimes of suitable surface modification for metallization.

Polystyrene (PS) and polyethylene (PE) samples were treated with argon and oxygen plasmas. Microwave electron cyclotron resonance (ECR) was used to generate the argon and oxygen plasmas and these plasmas were used to modify the surface of the polymers. The samples were processed at different microwave powers and treatment time and the surface modification of the polymer was evaluated by measuring the water contact angle of the samples before and after the modification. Decrease in the contact angle was observed with the increase in the microwave power for both polystyrene and polyethylene. Plasma parameters were assessed using Langmuir probe measurements. Fourier transform infrared spectroscopy showed the evidence for the induction of oxygen-based functional groups in both polyethylene and polystyrene when treated with the oxygen plasma. Argon treatment of the polymers showed improvement in the wettability which is attributed to the process called as CASING, on the other hand the oxygen plasma treatment of the polymers showed surface functionalization. Correlation between the plasma parameters and the surface modification of the polymer is also discussed.

X-ray photoelectron spectroscopy (XPS) has been used to study the effects of flame treatment on three propylene polymers, i.e. a homopolymer, an ethylene-propylene copolymer and a rubber-modified polypropylene. Angle-resolved XPS has shown an enrichment in oxygen concentration at the near surface for all three propylene polymers when treated with a mild flame. A depletion in oxygen has been shown at the near surface of the rubber-modified polypropylene treated with an intense flame. The use of simple surface composition models shows that the oxidation depth induced by a mild flame treatment is around 50 Å, and that oxygen-containing functional groups may have reoriented or migrated a few ångströms away from the near surface of the rubber-modified polypropylene during the treatment with an intense flame.

Low pressure plasma treatment using radiofrequency (rf) discharge of argon gas was employed to improve the hydrophilicity of polypropylene. The effects of argon plasma on the wettability, surface chemistry and surface morphology of polypropylene were studied using static contact angle measurements, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Increase in surface energy of polypropylene was observed as a result of argon plasma treatment. SEM and AFM images revealed the increased surface roughness. A set of identified process variables (rf power, pressure, argon flow rate and time) were used in this study and were optimized using central composite design (CCD) of response surface methodology (RSM). A statistical model was developed to represent the surface energy in terms of the process variables mentioned above. Accuracy of the model was verified and found to be high.

The purpose of this work was to investigate the influence of a low-pressure, low-frequency ammonia plasma treatment on the wettability of polypropylene (PP) thin films and its consequences on the adhesion properties of such treated films to thermally evaporated aluminium coatings. The wettability was determined by contact angle measurements while the adherence was evaluated by a U-Peel test especially suited to thin flexible substrates with thin metallic layers. Furthermore, an image processing system was used to measure the percentage of the peeled-off metal. Measurements carried out on NH₃ plasma-treated PP films revealed a sharp increase in the wettability and in the adhesion properties for treatment times as short as 1 s. Electron-induced X-ray emission spectroscopy and X-ray photoelectron spectroscopy showed the formation of new chemical bonds at Al/NH₃ plasma-treated PP film interfaces. The new types of bonds have been characterized by well-defined chemical states (C–NH_x, CO–NH, Al–N–C) in the N 1s (and C 1s) spectra. The interfacial complexes Al–N–C and Al–N–CO are formed by the NH₃ plasma treatment which creates at the PP surface active sites (N(C–NH_x) and N(CO–NH)) which react with the evaporated aluminium atoms. These interfacial bonds play an important role in the enhancement of the metal/polymer adhesion.

Pigment-coated, surface-sized, and surface-sized copy papers were treated with conventional corona, experimental pilot-scale plasma and laboratory-scale plasma. All the treatments increased the surface energy and oxidized the surface. The changes in the surface chemistry depended on treatment time and composition of the substrate surface. It seems that plasma especially oxidizes the long polymer chains, such as surfactants and other paper chemicals, on the surface of the paper. The ToF-SIMS distribution maps indicated that the pilot-scale treatment led to an uneven CO⁺ group distribution, whereas laboratory scale treatment gave a more even distribution of CO⁺ groups. In addition to chemical changes, topographical changes due to plasma treatment were detected. The RMS roughness increased for pigment-coated paper, whereas plasma treatment induced small nodules between the paper pigment particles with pigmented and surface-sized paper. The increase in roughness was also found to increase the wettability. This serves as a demonstration of roughness-induced increase of surface energy of the samples.

Poly(tetrafluoroethylene) (PTFE) surfaces are modified with remote and direct Ar plasma, and the effects of the modification on the hydrophilicity of PTFE are investigated. The surface microstructures and compositions of the PTFE film were characterized with the goniometer, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Results show that the remote and direct plasma treatments modify the PTFE surface in morphology and composition, and both modifications cause surface oxidation of PTFE films, in the forming of some polar functional groups enhancing polymer wettability. When the remote and direct Ar plasma treats PTFE film, the contact angles decrease from the untreated 108–58° and 65.2°, respectively. The effect of the remote Ar plasma is more noticeable. The role of all kinds of active species, e.g. electrons, ions and free radicals involved in plasma surface modification is further evaluated. This shows that remote Ar plasma can restrain the ion and electron etching reaction and enhance radical reaction.

An attempt was made to study the effect of plasma surface activation on the adhesion of UV-curable sol-gel coatings on polycarbonate (PC) and polymethylmethacrylate (PMMA) substrates. The sol was synthesized by the hydrolysis and condensation of a UV-curable silane in combination with Zr-n-propoxide. Coatings deposited by dip coating were cured using UV-radiation followed by thermal curing between 80 °C and 130 °C. The effect of plasma surface treatment on the wettability of the polymer surface prior to coating deposition was followed up by measuring the water contact angle. The water contact angle on the surface of as-cleaned substrates was 80° ± 2° and that after plasma treatment was 43° ± 1° and 50° ± 2° for PC and PMMA respectively. Adhesion as well as mechanical properties like scratch resistance and taber abrasion resistance were evaluated for coatings deposited over plasma treated and untreated surfaces.

Surface properties of polycarbonate (PC), polypropylene (PP), polyethylene terephthalate (PET) samples treated by microwave-induced argon plasma have been studied with contact angle measurement, X-ray photoelectron spectroscopy (XPS) and scanned electron microscopy (SEM). It is found that plasma treatment modified the surfaces both in composition and roughness. Modification of composition makes polymer surfaces tend to be highly hydrophilic, which mainly depended on the increase of ratio of oxygen-containing group as same as other papers reported. And this experiment further revealed that CO bond is the key factor to the improvement of the hydrophilicity of polymer surfaces. Our SEM observation on PET shown that the roughness of the surface has also been improved in micron scale and it has influence on the surface hydrophilicity.

The industrial use of polypropylene (PP) films is limited because of undesirable properties such as poor adhesion and printability. In the present study, a DC glow discharge plasma has been used to improve the surface properties of PP films and make it useful for technical applications. The change in hydrophilicity of modified PP film surface was investigated by contact angle (CA) and surface energy measurements as a function of exposure time. In addition, plasma-treated PP films have been subjected to an ageing process to determine the durability of the plasma treatment. Changes in morphological and chemical composition of PP films were analyzed by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The improvement in adhesion was studied by measuring T-peel and lap shear strength. The results show that the surface hydrophilicity has been improved due to the increase in the roughness and the introduction of oxygen-containing polar groups. The AFM observation on PP film shows that the roughness of the surface increased due to plasma treatment. Analysis of chemical binding states and surface chemical composition by XPS showed an increase in the formation of polar functional groups and the concentration of oxygen content on the plasma-processed PP film surfaces. T-peel and lap shear test for adhesion strength measurement showed that the adhesion strength of the plasma-modified PP films increased compared with untreated films surface.

This paper investigates the surface modification of Parylene-C thin films under various oxygen plasma treatment conditions, such as power intensity (50:400 W) and exposure time (1:20 min). The extent of hydrophilicity was investigated through contact angle measurements, and correlations between treatment parameters, film thickness, restoration of hydrophobicity and etching rates were experimentally established. We also demonstrate the selective modification of Parylene-C films, facilitating distinct hydrophilic and hydrophobic areas with μm-resolution that can be exploited in self-alignment applications.