Effect of surface roughness on the adhesion of electrolessly plated platinum to poly(ethylene terephthalate) films

Poly(ethylene terephthalate) films were treated with aqueous sodium hydroxide solutions of different concentrations for various times. The rate of weight loss increased with the addition of a swelling agent (methylene chloride) or a cationic surfactant. The surface roughness of the treated films was determined from atomic force microscopy (AFM) and pore diameter was obtained from scanning electron microscopy (SEM). In general, surface roughness was found to increase with increasing weight loss for the treated films. A maximum roughness was obtained for samples with a weight loss of approximately 15-20%, beyond which the roughness of the samples decreased. The addition of methylene chloride and surfactant resulted in an almost two-fold increase in the roughness for all treatment times investigated. The adhesion of electrolessly plated platinum film was dependent on the contact area produced by chemical treatment. Treatments producing smaller diameter pores of greater depth gave better adhesion.     

Measurement of the adhesion between single melamine-formaldehyde resin microparticles and a flat fabric surface using AFM

An understanding of the adhesion of microparticles, particularly microcapsules, containing a functional component to a fabric surface is crucial to an effective application of this component to the fibre. Fabric surface is very rough; hence, direct measurement of the adhesion of single microparticles to surfaces with a roughness greater than the particle diameter is difficult. In the study reported here, cotton films were generated by dissolving cotton powder in an organic solvent and their properties including surface roughness, thickness, contact angle and purity were characterised. The adhesive forces between single melamine-formaldehyde (MF) resin microparticles and a cotton film under ambient conditions with a relative humidity of above 40% were measured using atomic force microscopy; they are considered to be dominated by capillary forces. It was found that there was little adhesion between a MF microparticle and a cotton film in an aqueous solution of sodium dodecylbenzene sulphonate as surfactant. Repulsion between them was observed, but it reduced with increase in the surfactant concentration and decrease in the pH of the solution. The repulsion contributions are thought to originate mainly from electrostatic repulsion. It is believed that the studies on the adhesion between single MF microparticles and a cotton film under ambient conditions or dispersed in surfactant solutions, are beneficial to the attempts to enhance the adhesion of microcapsules to fabric surfaces via a modification of their surface composition and morphology.     

Improved adhesion of aluminum layers deposited on plasma and thermally treated poly(paraphenylene-vinylene) films substrates

Searching for better adhesion properties of metallic thin films to polymer substrates, we have studied the influence of the plasma and thermal treatments of poly(paraphenylene-vinylene) thin films on their adhesion to aluminum layers. The adhesion was found to be substantially increased when the polymer surface was treated with oxygen by RF sputtering, or when it was kept at high temperature prior to the metal deposition. An attempt has been made to explain the adhesion improvement in terms of surface analysis (XPS) and scanning electron microscopy (SEM) results of the treated surfaces. Both the metal-oxygen-carbon complex formation at the interface and the roughness induced by the oxygen treatment were found to be the reasons for the improved adhesion properties.     

光催化多孔TiO2薄膜的表面形貌对亲水性的影响

从含聚乙二醇（ＰＥＧ）的钛醇盐溶胶前驱体中通过溶胶－凝胶工艺在普通钠钙玻表面制备了多孔锐钛矿型ＴｉＯ２纳米薄膜。用扫描电镜（ＳＥＭ）,Ｘ射线光电子能谱（ＸＰＳ）和红外光谱（ＩＲ）分析了ＴｉＯ２薄膜表面的微结构,结果表明,随着前驱物中聚乙二醇的加入量和分子量的增加,聚乙二醇热分解后的薄膜中产生的气孔就越多且孔径越大,同时ＴｉＯ２薄膜表面的羟基含量增加且表面粗糙度增大。接触角测试表明：随着薄膜中气孔数     

Surface analysis and printability studies on electron beam-irradiated thermoplastic elastomeric films from LDPE and EVA blends

The electron beam-initiated surface modification of films prepared from various blends of low-density polyethylene (LDPE), ethylene vinyl acetate (EVA), and ditrimethylol propane tetraacrylate (DTMPTA) was carried out over a range of radiation doses (20-500 kGy) and concentrations of DTMPTA. The films were characterized by Fourier transform infrared-attenuated total reflectance (FT-ATR) spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), contact angle measurements, and peel adhesion. The printability of the films was also measured. FT-ATR and XPS revealed that the surface polarity of the films made from a 50 : 50 blend of LDPE and EVA increased up to a radiation dose of 100 kGy, compared with the unirradiated sample. The polarity decreased after 100 kGy radiation. Surface pitting and roughness were observed in the SEM photomicrographs of the same films, irradiated at higher radiation doses. Higher values of the surface energy were obtained at 100 kGy for the samples without DTMPTA and for the samples containing 3 wt% DTMPTA. Excellent printability was observed for all the films irradiated above an irradiation dose of 20 kGy. The data on the printability and peel adhesion of the irradiated films could be explained by surface energy, XPS, and SEM results.     

Adhesion Improvement of Poly(Phenylene-Vinylene) Substrates Induced by Argon-Oxygen Plasma Treatment

Copper films evaporated on argon-oxygen plasma-treated poly(phenylene-vinylene) films have been studied by scratch test, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The adhesion of the metallic film to the polymer substrate was greatly enhanced after treatment and found to increase with the treatment time. SEM observation of the treated samples revealed that the morphology of the polymer surface was gradually changed with the treatment time as compared with that of the bare polymer film. On the other hand, XPS analysis of the polymer-metal interface showed that the bonding between carbon, oxygen and copper were subsequently modified as compared with those obtained in untreated samples. The high adhesion strength observed on these substrates was related to the modification in the surface morphology on the one hand and to the formation of new compounds at the polymer-metal interface on the other. The nature of the interfacial layer and its influence on the adhesion of the copper layer was discussed by comparing the results with those obtained in poly(phenylene-vinylene) (PPV)-Al systems.     

Adhesion Improvement of Poly(Phenylene-Vinylene) Substrates Induced by Argon-Oxygen Plasma Treatment

Copper films evaporated on argon-oxygen plasma-treated poly(phenylene-vinylene) films have been studied by scratch test, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The adhesion of the metallic film to the polymer substrate was greatly enhanced after treatment and found to increase with the treatment time. SEM observation of the treated samples revealed that the morphology of the polymer surface was gradually changed with the treatment time as compared with that of the bare polymer film. On the other hand, XPS analysis of the polymer-metal interface showed that the bonding between carbon, oxygen and copper were subsequently modified as compared with those obtained in untreated samples. The high adhesion strength observed on these substrates was related to the modification in the surface morphology on the one hand and to the formation of new compounds at the polymer-metal interface on the other. The nature of the interfacial layer and its influence on the adhesion of the copper layer was discussed by comparing the results with those obtained in poly(phenylene-vinylene) (PPV)-Al systems.     

Wetting and adhesion of water-borne printing inks on surface-modified polyolefins

Polyolefin films were surface-modified by different methods to improve the wetting and adhesion of water-borne printing inks. Polyethylene (PE) films were treated with corona at various energy levels. Surface-modified PE films were characterized by contact angle measurements and electron spectroscopy for chemical analysis (ESCA). Good wetting was already achieved with treatment at a lower energy level. Various degrees of adhesion were obtained at various degrees of treatment. A hydrophilic monomer, 2-hydroxyethylmethacrylate (HEMA), was polymerized onto the surfaces of polypropylene (PP) with radiation-induced grafting, which was carried out at two different radiation doses. In both cases, a thick, visible layer of polyHEMA was formed on the surface of PP, and satisfactory wetting was already achieved at lower radiation doses. Scanning electron microscopy (SEM) showed that different degrees of roughness were achieved at various radiation doses. Like the case of corona-treated PE, different degrees of adhesion were obtained at different degrees of surface treatment. This study shows that improved wetting alone is not satisfactory for good practical adhesion', regardless of the surface modification method used.     

Which is more effective for protein adsorption: surface roughness,surface wettability or swelling? Case study of polyurethane films prepared from castor oil and poly(ethylene glycol)

In order to investigate the effects of surface roughness, surface wettability and swelling on protein adsorption, polyurethane films were prepared from castor oil (CO) and poly(ethylene glycol)‐3000 (PEG) using one‐shot bulk polymerization. Hexamethylene diisocyanate and 1,4‐butanediol were used as isocyanate and chain extender, respectively. The hydrophilicity of the polyurethane films was adjusted by varying the ratio of CO to PEG. The surface of the polyurethane films was treated using plasma polymerization in the presence of acrylic acid vapour. Therefore, the polyurethane films could be obtained with the same hydrophilicity but with different roughness. The hydrophilicity of untreated and treated polymer films was examined using contact angle measurements. The surface topology of the polymer films was investigated using scanning electron microscopy and atomic force microscopy. Adsorption of bovine serum albumin and bovine serum fibrinogen on treated and untreated polymer films was determined and the performance of the films was compared. After evaluation of all results it is found that surface roughness and swelling are as important as hydrophilicity for protein adsorption in the case of CO/PEG‐based polyurethanes. © 2012 Society of Chemical Industry     

Synthesis of WO3 thin films by surfactant mediated spray pyrolysis

WO₃ thin films were prepared by surfactant mediated spray pyrolysis deposition on fluorine-doped tin oxide (FTO) conductive glass using hexadecylthymethylammonium bromide (HTAB) as structure-directing agent. The crystalline structure, topography, electrical conductivity and optical properties were investigated as function of cationic surfactant concentration. High transparency and conductivity were obtained for the sample which contained the lowest amount of surfactant (50 ppm) in the spraying solution. Significant changes in the morphology were observed with increasing HTAB addition level; samples lost their homogeneity and porosity, while the layer roughness increased. The surfactant by-products resulted after annealing were investigated based on FTIR analysis and a decomposition scheme was proposed. The modified surface composition and morphology influenced the hydrophilic character of the samples.     

New etching method of PVC plastic for plating by ultrasound

An ultrasonic etching method is effective to pretreatment of PVC plastic for plating without chemical pollution. After being etched for 60 min by 28-kHz ultrasound, the improvement of adhesion strength of Cu–PVC can increase 13%, compared with that of chromic–sulphuric acid etching. The mechanism of adhesion improvement was studied by examination of weight loss, surface roughness, scanning electron microscopy, image analysis, and X-ray photoelectron spectroscopy. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1411–1416, 1998     

Reactivity of the raw materials and their effects on the structure and properties of rigid polyurethane foams

Formulations for rigid polyurethane foams (RPUFs) based on crude 4,4′‐diphenylmethane diisocyanate, polyether polyol, triethylenediamine, 1,4‐butane diol, poly(siloxane ether), methylene chloride, and water were studied. The stoichiometric ratios of various foam ingredients and their effects on physical properties such as the cream time, gel time, tack‐free time, and density of the RPUF samples were studied. The results indicated that the rate of RPUF formation increased with the catalyst (triethylenediamine and tin) and water content. The density of the RPUF samples blown with water, methylene chloride, and a mixture of water and methylene chloride decreased from 240.1 to 33.4 kg/m³ with an increase in the blowing agent contents. However, the RPUF density increased with increasing contents of 1,4‐butane diol. The cell morphology and thermal properties of the RPUF samples were investigated with scanning electron microscopy, thermogravimetric analysis, derivative thermogravimetry, and differential thermal analysis. Scanning electron microscopy results revealed an average increase in the cell size of the RPUF samples from 162 to 278 μm with increased water content. A thermal behavior study indicated that the RPUF samples decomposed in nitrogen and degraded in air through two and three weight‐loss stages, respectively. Foam pyrolysis in nitrogen and combustion in air led to 15 and 0% char residue, respectively. The results indicated that the thermal stability of the RPUFs was better in nitrogen than in an air atmosphere. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Reprocessing of chromed ABS parts with chemical pickling and new chrome plating

In this work, chrome‐plated acrylonitrile–butadiene–styrene (ABS) parts containing defects in the deposited metal layer were pickled up to two times in hydrochloric and nitric acid under different immersion times. The influence of pickling on the properties of ABS was evaluated by thermogravimetric analysis, differential scanning calorimetry, Fourier transform infrared spectroscopy–attenuated total reflection (FTIR–ATR), scanning electron microscopy, atomic force microscopy, and roughness. The pickled parts were again chromed and evaluated by visual inspection and adhesion. The metallic layer was removed and a slight yellowing of the samples surface with the increase of pickling time. There were no significant changes in the thermal behavior of the material. Some of the components of ABS were removed, as evidenced by the reduction of the absorption peaks intensity in FTIR–ATR, by the increase of roughness and presence of pores on the surface. With the increase of the immersion time and the number of pickling, there was the formation of pores with larger sizes and decrease in roughness, making metal–polymer adhesion difficult. Only one pickling, under immersion time of 30 min, was adequate for the removal of the metallic layer, allowing new chrome plating. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46131.     

Electrochemical deposition of zinc–polystyrene composites in the presence of surfactants

The electrochemical codeposition of polystyrene particles and zinc on a rotating cylinder electrode was investigated. Rheological measurements indicate strong aggregation of the PS particles in the zinc deposition electrolyte. Addition of cetylpyridinium chloride, a cationic surfactant, prevents aggregation and enhances polystyrene codeposition. Other surfactants also increase suspension stability, but diminish polystyrene codeposition, irrespective of their charge. Hence, the surfactant charge does not affect polystyrene codeposition. The variation of polystyrene incorporation with the amount of suspended polystyrene, current density and electrode rotation speed signifies that polystyrene codeposition with zinc is determined by the competition between particle removal forces and particle adhesion forces at the cathode surface. The effect of the surfactants can be related to changes in surface roughness of zinc due to surfactant adsorbed on the electrode. Cetylpyridinium chloride behaves differently from the other surfactants, because it is reduced at the cathode.     

Adhesion to Sodium Naphthalenide Treated Fluoropolymers. Part III. Mechanism of Adhesion

Adhesion of fluoropolymers to copper and to other polymers is examined using a range of fluoropolymer types (PTFE, PFA, extruded, skived and cast films), surface modification techniques such as sodium naphthalenide (Na/naphth), acid stripping and lamination to produce surfaces of controlled roughness, and three tests of adhesion (90 degree peel tests, torsional shear tests and stripping of transmission electron microscopy (TEM) replicas). A combination of chemical and physical modification is required to produce good adhesion, with the relative importance of each dependent upon the specific adhesion test used. For relatively smooth-surfaced films, Na/naphth appears to function by increasing both the chemical functionality and the mechanical integrity of a surface layer. Untreated PTFE and PFA show interfacial failure and negligible adhesion. Smooth-surfaced PTFE with superficial surface modification, e.g. after lamination to shiny copper foil or after acid stripping of defluorinated material, often fails by fibrillation of the fluoropolymer surface. For short sodium etch times, adhesion is improved and the failure mode is interfacial. For long etch times, there is a mixed mode of failure. Fibrillation in smooth-surfaced PFA systems was not observed. Adequate adhesive strength in these systems could only be achieved by an increase in the surface roughness. The best adhesion could be achieved by surface roughening, followed by Na/naphth treatment. For such PTFE surfaces plated with copper, peel and shear tests showed a mixed mode of failure, with copper and fluoropolymer found on both failure surfaces by x-ray photoelectron spectroscopy (XPS) and energy dispersive x-ray spectroscopy (EDS). Extensive fibrillation occurred at the locus of failure. Provided chemical modification is adequate to allow wetting, the roughness of the surface dominates the properties of the adhesive bond. Prolonged Na/naphth treatment (e.g. one hour) causes a reduction in peel strengths.     

Adhesion to Sodium Naphthalenide Treated Fluoropolymers. Part III. Mechanism of Adhesion

Adhesion of fluoropolymers to copper and to other polymers is examined using a range of fluoropolymer types (PTFE, PFA, extruded, skived and cast films), surface modification techniques such as sodium naphthalenide (Na/naphth), acid stripping and lamination to produce surfaces of controlled roughness, and three tests of adhesion (90 degree peel tests, torsional shear tests and stripping of transmission electron microscopy (TEM) replicas). A combination of chemical and physical modification is required to produce good adhesion, with the relative importance of each dependent upon the specific adhesion test used. For relatively smooth-surfaced films, Na/naphth appears to function by increasing both the chemical functionality and the mechanical integrity of a surface layer. Untreated PTFE and PFA show interfacial failure and negligible adhesion. Smooth-surfaced PTFE with superficial surface modification, e.g. after lamination to shiny copper foil or after acid stripping of defluorinated material, often fails by fibrillation of the fluoropolymer surface. For short sodium etch times, adhesion is improved and the failure mode is interfacial. For long etch times, there is a mixed mode of failure. Fibrillation in smooth-surfaced PFA systems was not observed. Adequate adhesive strength in these systems could only be achieved by an increase in the surface roughness. The best adhesion could be achieved by surface roughening, followed by Na/naphth treatment. For such PTFE surfaces plated with copper, peel and shear tests showed a mixed mode of failure, with copper and fluoropolymer found on both failure surfaces by x-ray photoelectron spectroscopy (XPS) and energy dispersive x-ray spectroscopy (EDS). Extensive fibrillation occurred at the locus of failure. Provided chemical modification is adequate to allow wetting, the roughness of the surface dominates the properties of the adhesive bond. Prolonged Na/naphth treatment (e.g. one hour) causes a reduction in peel strengths.     

Investigating the effect of power/time in the wettability of Ar and O2 gas plasma-treated low-density polyethylene

Low-pressure glow discharges of Ar or O₂ gas plasmas were used to increase the wettability of low-density polyethylene (LDPE) films in order to improve their adhesion properties hence making them useful in technical applications. Surface free energies of such films were estimated by the aid of contact angle measurements at different exposure power/time combinations for a series of test liquids. Additionally, plasma-treated samples were subjected to several aging processes to determine the durability of different plasma treatments. Characterization of the surface changes due to plasma treatments were carried out by means of attenuated total reflectance, Fourier transform infrared spectroscopy (FTIR-ATR) to determine the presence of polar species such as hydroxyl, carbonyl, carboxyl, etc. groups. Furthermore, atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used to evaluate changes in surface morphology and roughness. Considering the semi-crystalline nature of the LDPE film, XRD studies were also carried out to determine changes in the percentage of crystalinity. The results showed that all low-pressure Ar or O₂ gas plasmas improve the wettability properties of LDPE films. Contact angles decreased significantly depending on the discharge powers and exposure times. Surface morphology was also found to vary with plasma discharge powers, exposure times, and the type of gas being used. Ar gas plasmas comparatively produced superior results.     

Gold nanoparticles deposited on glass: physicochemical characterization and cytocompatibility

Properties of gold films sputtered under different conditions onto borosilicate glass substrate were studied. Mean thickness of sputtered gold film was measured by gravimetry, and film contact angle was determined by goniometry. Surface morphology was examined by atomic force microscopy, and electrical sheet resistance was determined by two-point technique. The samples were seeded with rat vascular smooth muscle cells, and their adhesion and proliferation were studied. Gold depositions lead to dramatical changes in the surface morphology and roughness in comparison to pristine substrate. For sputtered gold structures, the rapid decline of the sheet resistance appears on structures deposited for the times above 100 s. The thickness of deposited gold nanoparticles/layer is an increasing function of sputtering time and current. AFM images prove the creation of separated gold islands in the initial deposition phase and a continuous gold coverage for longer deposition times. Gold deposition has a positive effect on the proliferation of vascular smooth muscle cells. Largest number of cells was observed on sample sputtered with gold for 20 s and at the discharge current of 40 mA. This sample exhibits lowest contact angle, low relative roughness, and only mild increase of electrical conductivity.     

Role of PLLA plasma surface modification in the interaction with human marrow stromal cells

The effects of oxygen‐based radio frequency plasma enhanced chemical vapor deposition (rf PECVD) on the surface of poly(L ‐lactide) (PLLA) polymers and the influence thereof on protein adsorption and on bone–cell behavior have been studied. Thin films and porous scaffolds based on PLLA polymer were developed, and the role of surface modifications were investigated extensively. PECVD surface treatments were used to alter surface functionality and modulate protein adsorption on the PLLA polymer matrix. In particular, Bovine Serum Albumine fluorescein isothiocyanate (fitc‐BSA) conjugate adsorption on patterned surfaces of treated PLLA was analyzed by fluorescence microscopy. Human marrow stromal cells (MSCs) were cultured on scaffolds and cell adhesion and morphology were assessed using fluorescence microscopy. The results indicated that the PLLA surface became hydrophilic and its roughness increased with the treatment time and it had a dominant influence on the adsorption process of the protein. The outcome of the plasma treatment of various PLLA surfaces has been shown to be the up‐regulator of the cell‐adhesive proteins expression and consequently the improvement of cell adhesion and growth. Oxygen‐treated PLLA promoted higher adhesion and proliferation of the MSCs in comparison to the untreated samples. It can be concluded that following plasma treatment, PLLA samples show enhanced affinity for osteoprogenitor cells. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Self-cleaning performance of sol–gel-derived TiO<Subscript>2</Subscript>/SiO<Subscript>2</Subscript> double-layer thin films

The self-cleaning properties of the TiO₂/SiO₂ double-layer films prepared by sol–gel method were investigated. Thin films were prepared by spin coating onto glass and then thermally treated at different temperatures, and characterized using X-ray diffraction, atomic force microscopy, field emission scanning electron microscopy, and UV–visible spectroscopy. The cross-sectional structure of the films was observed by FESEM. The surface roughness of the films was characterized by AFM. The root mean square surface roughness of the thin films was below 2 nm, which should enhance their optical transparency. The photo-induced hydrophilicity of the films was evaluated by water contact angle measurement in air. The photocatalytic activity of the films was studied by the photocatalytic degradation of methylene blue under UV light irradiations. The TiO₂/SiO₂ double-layer thin films are plausibly applicable to developing self-cleaning materials in various applications such as windows, solar panels, cement, and paints.