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In this study, the performance of sandalwood (SW), as an efficient potential filler material for high-density polyethylene (HDPE), was investigated in detail. Firstly, the characterization of SW was conducted by the determination of chemical composition with chemical and thermal analysis methods. The distribution of SW particles, which were used in composite fabrication, was obtained by using a dynamic light scattering analyzer. Then, the composites of SW, whose weight fractions varied from 5% to 20%, with HDPE were produced in a high-speed thermokinetic mixer. The detailed characterization of composites was made by using thermogravimetric analysis, scanning electron microscopy, X-ray diffraction analysis, differential scanning calorimetry, dynamic mechanical analysis (DMA), Fourier transform infrared, thermal conductivity measurements, and tensile and three-point bending tests. From DMA, storage modulus and loss modulus values of the HDPE matrix increased with increasing the weight fraction of SW. It is clearly seen that SW incorporation into HDPE at weight fractions of 5% and 20% exhibited the best improvement in terms of tensile and flexural strengths, respectively. It can be noted that the reinforcement effect of SW for HDPE is more prominent at high temperatures.

The aim of this study is to investigate the reinforcing effect of Ceratonia siliqua (CS) powder as a novel natural filler for polypropylene (PP) based composites. CS powder up to 20 wt% was filled into PP matrix by using high speed thermo kinetic mixer. Mechanical and thermal properties of CS filled PP based composites were investigated by tensile and three point bending test, dynamic mechanical analysis, thermogravimetric analysis, differential scanning calorimetry analysis, fourier transform infrared analysis, and thermomechanical analysis. Morphology of the composites was also investigated by scanning electron microscopy. By filling 5% and 10% of CS into PP, tensile strength and flexural strength of PP increased by about 32 and 23%, respectively. This indicates that CS has a great potential to be used as reinforcing filler for PP composites. CS filling into PP led to lower coefficient of thermal expansion values which could help preventing the thermal expansion.

The aim of this study is to investigate the filling properties of an agricultural waste, olive pomace powder (OP), for polypropylene (PP) matrix material. Different weight fractions of OP (from 10 to 40 wt %), which has a median particle size of 21.36 mu m (D50) mu m, were loaded into PP by high-speed thermo kinetic mixer. In this research, the effects of weight fraction of OP within PP on mechanical, viscoelastic, thermal, chemical, crystallographic, and morphological properties of PP composites were investigated by tensile and three point bending test, dynamic mechanic analysis, thermogravimetric analysis and differential scanning calorimetry, Fourier transform infrared analysis, X-ray diffraction analysis, and scanning electron microscopy. When 40 wt% OP filler was loaded into PP, the Young's modulus and flexural modulus of PP increased by about 62.5% and 19%, respectively. The storage modulus and thermal stability of PP were remarkably enhanced with increasing OP weight fraction. (C) 2017 Elsevier Ltd. All rights reserved.

In-plane alignment of graphene nanoplatelets (GNPs) in thin thermal interface material layers suppresses the through-plane heat transport, which limits the performance of materials. In order to suppress the in-plane alignment of the GNP filler within polypropylene (PP) and increase the through-plane component, modification of GNP (MG) was performed in this study. For this aim, GNP was treated with diallyldimethylammonium chloride solution and filled with PP at different weight fractions by using a laboratory type high-speed thermo-kinetic mixer. The effect of MG loading into PP on thermal conductivity and surface resistivity of PP was measured. With using MG as a conductive filler for PP, instead of GNP, through-plane conductivity increased by 11%, however in-plane conductivity decreased by 33%. Modified GNP-filled PP showed better through-plane conductivity and surface resistivity than those of unmodified GNP-filled PP. Tensile and three point bending tests were performed to determine tensile and flexural properties of composites. Dynamic mechanical analysis was carried out to evaluate viscoelastic properties, such as storage modulus and loss modulus of composites. The thermal properties of samples were measured by using a differential scanning calorimetry, thermogravimetric analysis, and thermo-mechanical analysis. Scanning electron microscopy was utilized to observe the fracture surfaces of the composites after tensile tests. (C) 2018 Society of Plastics Engineers

EgeUn###, Pumice stone (P), which is as a cheap material, can be a good candidate for filling material for polymers because of its high thermal resistance. Its effect on properties of polypropylene (PP) has not been studied in detail up to now. The mechanical, viscoelastic, thermal, morphological, crystallographic, and thermomechanical behaviors of PP filled with P powder were studied. The composites were produced by adding different weight fractions of P powder (0-40 wt%) into PP using a high-speed thermo kinetic mixer and compression molding. The highest tensile and flexural strength values, 26.5 and 46.4 MPa, respectively, were obtained when 10 wt% of P powder was filled into PP. Besides, the storage and loss modulus of PP was increased with the addition of P powder. The onset decomposition temperature of PP increased by 39 degrees C with P powder loading into PP. The addition of P powder into PP led to a significant increase on the crystallinity of PP. It is interesting to report that thermal conductivity of PP was increased with increasing weight fraction of P powder.

Polypropylene (PP) was filled with synthetic graphite (SG) and graphene nanoplatelets (G) at different weight fractions. Composites were prepared by the melt mixing process by using a co-rotating twin screw extruder. Mechanical tests were carried out to determine tensile and flexural properties of composites. Dynamic Mechanical Analysis of composites was performed to determine their thermo-mechanical properties, such as storage modulus and loss modulus. Scanning Electron Microscopy was used to observe the fracture surfaces of the composites after tensile tests. The effect of SG and G on thermal properties such as melting and crystallization temperature, thermal conductivity, thermal stability, and coefficient of thermal expansion of PP was investigated. Tensile strength and flexural strength of PP increased with the addition of 10 wt% SG. The highest thermal conductivity achieved in this study at 50 wt% SG and 3 wt% G loading was 4.6 W/mK. POLYM. COMPOS., 40:277-287, 2019. (c) 2018 Society of Plastics Engineers

Seki, Yoldas/0000-0002-2225-1236; ATAGUR, Metehan/0000-0002-1916-457X, WOS:000448083600027, Recycled carbon fiber reinforced polypropylene (PP) composites were fabricated by using high speed thermo-kinetic mixer. The effect of recycled carbon fiber on the morphological, chemical, physical, thermal, and mechanical properties of PP composites was investigated. The results indicate that the tensile and flexural strength of PP increase with addition of recycled carbon fiber up to 20 wt%. When 40 wt% recycled carbon fiber was added into PP, the tensile and flexural moduli were increased by about 177 and 359%, respectively. The coefficient of thermal expansion was found to be decreased by increasing recycled carbon fiber weight fraction. The addition of low weight fraction of recycled carbon fibers (up to 5 wt%) increased the nucleation process on PP crystallization. POLYM. COMPOS., 39:3656-3665, 2018. (c) 2017 Society of Plastics Engineers

In this study, multilayer graphene (Gr)-reinforced cellulose composites were synthesized by using 1-ethyl-3-methylimidazolium diethylphosphonate ionic liquid. The composites were fabricated via dissolving the cellulose in 1-ethyl-3-methylimidazolium diethylphosphonate and Gr loading at different ratios (0.2, 0.4, and 0.6 wt.%). Both sides of the composites were coated with gold leaf to generate electrodes. The effect of Gr loading on chemical functional groups, crystallographic properties, thermal stability, and morphological and mechanical properties of cellulose film was investigated by Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, and tensile test, respectively. Electromechanical behavior of the cellulose composite films reinforced with Gr (0.2, 0.4, and 0.6 wt.%) was investigated under DC excitation voltages of 1, 3, 5 and 7 V. Gr loading of 0.2 wt.% increased maximum tip displacement by 400% when the actuator is excited with 3 V.

The effect of gold electrode thickness (10, 27, 45, 67 and 80 nm) on the electromechanical performance of Nafion-based Ionic Polymer Metal Composite (IPMC) actuators was investigated in this study. The mechanical, morphological, electrical properties and electroactive behaviors of IPMC under direct current voltage (DC) and alternating voltage (AC) were examined. The tip displacement and maximum blocking force of actuators under various electrical stimulations were measured. In order to define transient response characteristics and quasi-steady state value of the actuators, DC excitations of 1, 3, 5, 7 and 9 V were used. Besides, to define bandwidth of the actuator samples, square wave excitation with magnitudes of 3, 5, and 7 V and frequencies of 0.1, 0.25, 0.5, 1, and 2 Hz were applied to actuator samples. The actuator having a gold electrode thickness of 45 nm produced maximum tip displacement among all actuators for all excitation DC voltages. In the square wave experiments, the higher cutoff frequencies were observed for the actuators with 27 and 45 nm electrode thicknesses. The blocking force of IPMC increased with increasing gold electrode thickness from 10 nm to 45 nm and decreased with increasing gold electrode thickness from 45 nm to 80 nm.

In this study, graphene nanoplatelets (0.10, 0.25, and 0.50 wt.%) were loaded into cellulose matrix to improve electroactive performance of cellulose-based composite actuators. Firstly, cellulosic films were produced by dissolving microcrystalline cellulose in 1-butyl-3-methylimidazolium chloride. Afterwards, graphene loaded cellulosic films were fabricated and gold leaf was coated on both surfaces of graphene loaded cellulose-based films. The changes in crystallographic properties and chemical functional groups of cellulose were investigated by X-ray diffraction and Fourier transform infrared analyses, respectively. Besides, thermal stability, electrical conductivity, and morphological properties of the films were examined by thermogravimetric analysis, electrical conductivity measurement, and scanning electron microscopy, respectively. The tensile strength and the Young's modulus of the films and actuators were also determined by tensile tests. The electroactive characteristics were analyzed under DC excitation voltages of 3 V, 5 V and 7 V. The time responses were evaluated via proposed experimental data based model. The performances of the actuators were compared in terms of maximum tip displacement, minimum tip displacement and time constant. (C) 2014 Elsevier Ltd. All rights reserved.

PubMed: 29253989, 2-s2.0-85032709453, In order to analyze the bending mechanism of the electroactive? chitosan-based actuator, different amounts of poly(diallyldimethylammonium chloride) (PDAD) were incorporated in chitosan solution. The effects of PDAD concentration on electromechanical performance of chitosan actuator were investigated under various excitation voltages. With the incorporation of PDAD into chitosan solution, crosslinked chitosan film acts as an actuator showing a considerable displacement behavior. However it can be noted that higher incorporation of PDAD into chitosan solution decreased the performance of the actuators. Thermal, viscoelastic, and crystallographic properties of the chitosan films were examined by thermogravimetric analysis, dynamic mechanical analysis, and X-ray diffraction analysis, respectively. The effect of incorporation of PDAD in chitosan-based film on morphological properties of chitosan film was determined by scanning electron microscopy. It was observed that the films involving PDAD have larger pore size than the PDAD free film. © 2017 Elsevier Ltd, 111M643, This study was supported by TUBITAK-The Scientific and Technological Research Council of Turkey , with a Project Number: 111M643.

Flax fibers were modified by argon and air atmospheric pressure plasma treatments to improve the mechanical properties of flax fiber-reinforced unsaturated polyester composites. Plasma treatments were carried out at plasma powers of 100, 200, and 300 W. Both plasma surface treatments were conducted to improve the tensile strength, tensile modulus, flexural strength, flexural modulus, interlaminar shear strength (ILSS), Mode I interlaminar fracture toughness (GIC), and Mode II interlaminar fracture toughness (GIIC). Moreover, the maximum improvement in the mechanical properties was obtained after air plasma treatment of flax fiber at a plasma power of 300 W. Tensile strength, flexural strength, ILSS, GIC, and GIIC values of flax fiber-reinforced polyester composites increased by nearly 34%, 31%, 39%, 35%, and 42%, respectively. However, for argon plasma-treated flax fiber-reinforced polyester composites, the mechanical properties of composite increased up to argon plasma power of 200 W.

The aim of this study is to examine the use of Ferula communis fibers as potential reinforcement in polymer composites. The fibers are extracted from the F. communis plant which grows in Selcuk, Izmir in western Turkey. The chemical composition of ferula fibers in terms of cellulose, lignin, and ash contents was determined. Surface functional groups of ferula fibers were obtained by fourier transform infrared and Xray photoelectron spectroscopy. Crystallinity index and crystallite size were determined by X-ray diffraction analysis. The morphology of ferula fibers was investigated through scanning electron microscopy, the thermal behavior through thermogravimetric and differential scanning calorimetry analyses. The real density of ferula fibers was measured by means of Archimedes method with ethanol. The mechanical properties of F. communis were measured through single fiber tensile tests. The interfacial shear strength (IFSS) in a polyester matrix has been estimated from the pull-out test. Crown Copyright (C) 2012 Published by Elsevier Ltd. All rights reserved.

The aim of this study is to characterize linden fibres as a novel cellulose-based fibre to be used as a reinforcement material in composites and to investigate the adhesion property to unsaturated polyester. Up to now, there is no report regarding the potential usability of linden fibre in composite applications. Linden fibres were extracted from the stem of a plant of Tilia rubra DC. subsp. caucasica (Rupr.) V.Engl. Characterization of linden fibres was studied by Fourier transform infrared, X-ray photoelectron spectroscopy, thermogravimetric analysis, X-ray diffraction analysis, tensile and pull-out tests. Morphological properties of the fibres were observed through scanning electron and optical microscopes. Initial degradation temperature of the linden fibre was reported to be 238℃. The tensile strength and the Young’s modulus of the linden fibres were calculated to be 675.4 ± 45.7 MPa and 61.0 ± 9.8 GPa, respectively. The interfacial shear strength of the linden fibre with unsaturated polyester matrix was computed as 26.15 ± 2.27 MPa via pullout test. This study offers an alternative and eco-friendly reinforcement material which may have usability potential in polymeric composites.

This study aims to produce a long-term antistatic acrylic-based film by incorporating ionic liquid (IL), 1-ethyl-2,3-dimethylimidazolium ethyl sulphate (EIL) into acrylic resin. After loading, characterisations of samples were conducted by mechanically, thermally and morphologically. In order to determine antistatic properties, surface resistivity of samples was measured by using at different time intervals. The results indicated that IL loaded polymers showed a good antistatic property for a long time. The effect of incorporation on tensile strength, tensile modulus, flexural strength and flexural modulus of polymer were also obtained. After loading process, tensile strength, tensile modulus, flexural strength and flexural modulus values decreased considerably. The decrement in tensile strength of polymer is much less than that in flexural strength. The effect of EIL incorporation into acrylic resin on thermal conductivity and surface wettability was also investigated. From scanning electron microscopy images, EIL particles in nano-size range were observed in polymer structure.

To increase the mechanical properties of recycled carbon fiber-reinforced polypropylene (PP) composites, recycled carbon fibers (RCF) were subjected to atmospheric plasma treatment at different plasma powers (100, 200, and 300W). The changes on surface topography and roughness of RCF were examined by atomic force microscopy. Plasma treatment of RCF increased the roughness value of RCF. The variation of surface elemental compositions and tensile strength of RCF were determined by using X-ray photoelectron spectroscopy and tensile test, respectively. Plasma-treated RCF-reinforced PP composites were fabricated using high speed thermo-kinetic mixer. Plasma treatment of RCF at 100W increased the tensile and flexural strength values of RCF-reinforced PP composites considerably by 17 and 11%, respectively. However, plasma treatment of RCF at higher plasma powers (200W and 300W) decreased tensile and flexural strength values of composites because of the etching of RCF. (c) 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47131.

Enhancement of the mechanical and vibrational properties of glass/polyester composites was aimed via matrix modification technique. To achieve this, unsaturated polyester was modified by incorporation of oligomeric siloxane in the concentration range of 1-3 wt%. Modified matrix composites reinforced with woven roving glass fabric were compared with untreated glass/polyester in terms of mechanical and interlaminar properties by conducting tensile, flexure, and short-beam shear tests. It was found that after incorporation of 3 % oligomeric siloxane into the polyester matrix, the tensile, flexural, and interlaminar shear strength (ILSS) values of the resulting composite increased by 16, 15, and 75 %, respectively. The increases in ILSS as well as in tensile and flexural properties were considered to be an indication of better fiber/matrix interaction as confirmed by SEM fractography images. Furthermore, the effect of oligomeric siloxane incorporation on the vibrational properties of the composites was investigated by experimental modal testing and the natural frequencies of the composites were found to increase with increasing siloxane concentration.

In this study, jute/polyester composites were fabricated. To improve the adhesion between jute fabric and polyester alkali-treated jute fabrics were treated with γ-methacryloxypropyltrimethoxysilane (γ-MPS). The effect of silane concentrations (0.1%, 0.3%, and 0.5%) on tensile properties, flexural properties, and interlaminar shear strength was investigated. Once jute fabrics were treated with 0.1% and 0.3% silane concentrations, the tensile properties of silane-treated jute polyester composites increased. However, when 0.5% γ-MPS was used in silane treatment, the tensile properties of jute/polyester composites decreased. 0.3% silane-treated jute/polyester composites exhibited superior improvements in terms of the flexure properties among the fabricated composites. Interlaminar shear strength measurements showed that best adhesion was provided by using 0.3% silane-treated jute/polyester composites. Good adhesion between silane-treated jute fabric and polyester was also confirmed by scanning electron microscope observations.

In this study, glass fibers. were modified using gamma-glycidoxypropyltrimethoxysilane of different concentrations to improve the interfacial adhesion at interfaces between fibers and matrix. Effects of gamma-glycidoxypropyltrimethoxysilane on mechanical properties and fracture behavior of glass fiber/epoxy composites were investigated experimentally. Mechanical properties of the composites have been investigated by tensile tests, short beam tests, and flexural tests. The short-beam method was used to measure the interlaminar shear strength (ILSS) of laminates. The tensile and flexural properties of composites were characterized by tensile and three-point bending tests, respectively. The fracture surfaces of the composites were observed with a scanning electron microscope. On comparing the results obtained for the different concentrations of silane solution, it was found that the 0.5% GPS silane treatment provided the best mechanical properties. The ILSS value of heat-cleaned glass fiber reinforced composite is enhanced by similar to 59% as a result of the glass fiber treatment with 0.5% gamma-GPS. Also, an improvement of about 37% in tensile strength, about 78% in flexural strength of the composite with the 0.5% gamma-GPS treatment of glass fibers was observed. POLYM. COMPOS., 30:1251-1257, 2009. (C) 2008 Society of Plastics Engineers

In this study, effects of fiber surface treatments on mechanical behavior and fracture mechanism of glass fiber/epoxy composites were investigated experimentally. To change the composition of the glass and regenerate to the hydroxyl groups, activation pretreatment of heat cleaned woven glass fabric was performed using (v/v) HCl aqueous solution at different concentrations before silane treatment. The treatment of silanization of heat cleaned and acid activated glass fibers with gamma-glycidoxypropyltrimethoxysilane were performed. In this work, short beam shear test has been conducted to determine the performance of the acid treatment and the silane treatment in terms of the interlaminar shear strength. The silane coating on the heat cleaned glass fibers increased the interlaminar shear strength of the composite. However, the silane coating on the acid activated glass fibers did not improve the interlaminar shear strength of the composite. In addition, the strengths of the glass fabric specimens in tension and flexure were investigated. When the glass fibers are first treated with HCl solution and then with silane coupling agent, the tensile strengths of the composites decreased significantly. Scanning electron photomicrographs of fractured surfaces of composites were performed to explain the failure mechanisms in the composite laminates broken in tension.

© 2015, Springer Science+Business Media Dordrecht.Electroactive behavior of carboxymethylcellulose (CMC)-based actuators was investigated in this study. CMC-based films were firstly fabricated by using 1-butyl-3-methylimidazolium bromide. Characterization studies of the CMC films were conducted by using Fourier transform infrared, X-ray diffraction analysis, thermogravimetric analysis, scanning electron microscopy, and tensile testing. CMC-based actuator films were produced by gold coating on both surfaces of CMC-based films. Polyethylene glycol (PEG) at different loadings (1, 1.5 and 2 g) was used to improve electroactive behavior of CMC based actuators. Maximum tip displacements were obtained under DC excitation voltages of 1, 3, 5 and 7 V. CMC based actuator loaded with 1.5 g PEG exhibited the largest tip displacement among other actuators for each excitation voltage. The PEG loading did not lead to considerable differences in tensile strength of CMC-based films. However, Young’s modulus decreased with PEG loading.

Rice husk (RH) reinforced wheat gluten/glycerol (Gly/Glut) and rice husk (R) reinforced wheat gluten-glycerol/chitosan-polyethylene glycol (Gly/Glut-CP) biocomposites with varying rice husk loading were prepared. Morphological, thermal, and mechanical properties of the biocomposites were investigated by scanning electron microscope, thermogravimetric analyzer, and tensile testing machine, respectively. Water absorption properties and surface functional groups of the biocomposite films were determined by weight measurement and attentuated total reflectance Fourier transform infrared spectroscopy, respectively. The results were discussed in terms of chitosan-polyethylene glycol (CP) and rice husk content. Although CP and 1-g rice husk addition decreased maximum degradation temperature of Gly/Glut film, adding of more rice husk did not considerably change the maximum degradation temperature. As a result of adding CP, the tensile strength of Gly/Glut film was increased by about 183%, whereas tensile modulus was decreased by about 34%. POLYM. ENG. SCI., 54:1477–1483, 2014. © 2013 Society of Plastics Engineers

High density polyethylene (HDPE) were filled with expanded graphite particles that have different particle sizes, 5-7 mu m (EG5) and 40-55 mu m (EG50) in diameter. Nanocomposites were prepared by the melt-mixing technique using EG5 and EG50 at different weight ratios. Transmission Electron Microscopy (TEM) was used to observe the morphology of the nanocomposites. X-ray diffraction patterns of EG5-HDPE and EG50-HDPE nanocomposites were investigated. Tensile tests were carried out to determine tensile strength, Young's modulus and elongation at break values. The storage modulus and loss modulus were evaluated by Dynamic Mechanical Analysis (DMA). The effect of EG5 and EG50 on electrical conductivity of HDPE was also determined. The tensile strength of HDPE increased 18.7% and 8.5% when 40 wt% EG5 and EG50 was added into HDPE, respectively. The storage modulus of EG5-HDPE and EG50-HDPE is higher compared to that of HDPE. Incorporation of EG5 and EG10 into HDPE also increased the relaxation transition peak of HDPE. The values of electrical conductivity for EG50-HDPE nanocomposites under the same filler content obtained higher in comparison with those for EG5-HDPE nanocomposites. (C) 2013 Elsevier Ltd. All rights reserved.

High-density polyethylene (HDPE)/graphite nanocomposites containing up to 30 vol% of graphite powder filler were prepared by melt mixing in a Brabender Plasticorder at 180 degrees C for 15 min. The nanocomposites were characterized for their rheological, dynamic mechanical, crystallographic, and electrical properties as a function of graphite loading. The results indicated that graphite loading affects storage modulus, loss modulus, complex viscosity, and conductivity of HDPE matrix. The storage modulus increases while the graphite loading increases in the studied concentration range (up to 30%). When the graphite loading was increased to 30%, storage modulus at room temperature was about 300% higher than that of pure HDPE. Also, the composites containing 20 and 30% graphite shows more conductivity than the others. POLYM. COMPOS., 2012. (C) 2012 Society of Plastics Engineers

In this study, the effect of oligomeric siloxane on the mechanical properties of jute fabric-reinforced low-density polyethylene (LDPE) composites is examined. After alkali treatment of jute fabric, oligomeric siloxane treatment is conducted to promote adhesion between jute fiber and polyethylene matrix. Mechanical properties of fabricated composites such as tensile strength, flexural strength, and interlaminar shear strength (ILSS) were evaluated. The tensile strength is observed to increase from 17.5 MPa for untreated jute fabric/LDPE composite to 27.7 MPa for oligomeric siloxane-treated alkalized jute fabric/LDPE composite. Provided that jute fabric is treated with alkali and oligomeric siloxane, a 39% increase is observed in the flexural strength. It is interesting to note that the effect of siloxane treatment after alkalization procedure of jute fabric on ILSS of jute/LDPE composite is due to the fact that 98% improvement is obtained. It can be observed that the adhesion between jute fiber and LDPE also improves to a great extent through both alkali and oligomeric siloxane treatment, respectively. These results are also confirmed by the SEM observations of fracture surfaces of jute/LDPE composites.

This study aims to form a functional film on the glass substrates by plasma polymerization of glycidoxypropyltrimethoxysilane (gamma-GPS). Low frequency plasma generator was used to prepare plasma polymer thin films of gamma-GPS (PlzP-gamma-GPS) on glass substrates at different plasma powers (30, 60 and 90W) and exposure times (5, 15 and 30 min). XPS analyses were utilized to reveal the presence of functional groups in plasma polymer films. When higher plasma powers are applied, relative amount of Si-C bonds decreases and the amount of Si-O bonds increases. Contact angle measurements were performed to evaluate surface characteristics. Atomic force microscopy (AFM) studies were carried out to elucidate morphological changes. From AFM observations, it was obtained that the surface roughness slightly increased with the increase of plasma power from 30 to 90 W. (C) 2009 Elsevier B.V. All rights reserved.