Contact Angle Of Films Research Articles

Enhanced Wettability and Transport Control of Ultrafiltration and Reverse Osmosis Membranes with Grafted Polyelectrolytes.

End-functionalized poly(acrylic acid) (PAA-silane) was synthesized with reversible addition-fragmentation chain-transfer (RAFT) polymerization and attached to both polysulfone ultrafiltration (UF) and polyamide reverse osmosis (RO) membranes through a nonimpairing, one-step grafting to approach in order to improve membrane surface wettability with minimal impact on membrane transport performance. After PAA grafting, composition and morphology changes on the membrane surface were characterized with Fourier transform infrared spectroscopy (FTIR) and atomic force microscopy (AFM). Static contact angle on PAA grafted membranes exhibited an increase in surface hydrophilicity and hence a potential enhancement in antifouling performance. The native contact angle on the polysulfone membrane systems was 86° and was reduced to 24° after modification, while the polyamide film contact angle decreased from 58° to 25°. The PAA layer endowed the porous UF membrane with dynamic control over the permeability and selectivity through the manipulation of the solution pH. The UF membrane with a 35 nm average pore size displayed a 115% increase in flux when the contact solution was changed from pH 11 to pH 3. This effect was diminished to 70% and 32% as the average pore size decreased to 20 and 10 nm, respectively. Modified RO membranes displayed no reduction in membrane performance indicating that the underlying materials were unaffected by the modification environment or added polymer. Model polyamide and polysulfone surfaces were reacted with the PAA-silane inside a quartz crystal microbalance (QCM) to help inform the deposition behavior for the respective membrane chemistries.

Study on the Properties of UHMW-PE Film

Some physicochemical properties of UHMW-PE film such as gas permeability, tensile strength, and corrosion resistance in acid with different immersion time, various concentrations and various solutions and rattler testing were studied. The obtained results showed that the values of gas permeability, tensile strength, elongation at break, and the temperature of dissociation at weight loss 5% was 546.57 cm3·m﹣2·24 h·0.1 MPa, 37.22 MPa, 368.00%, 360°C, respectively. In different concentration acid, the surface resistance of film accumulated to some extent with immersion time increasing, together with that the higher acid concentration was, the lower the surface resistance of film was. Moreover, the contact angle of films gradually increased with the acid concentration decreasing and the increase of immersion time. After wear testing, the mass of UHMW-PE film did not nearly change, while the contact angle became larger with the number of turning increasing and the value was more than 90°.

Development of a sensitive SPR biosensor for C-reactive protein (CRP) using plasma-treated parylene-N film

Parylene-N film has high protein immobilization property after plasma-treatment. In this work, the optimum conditions for plasma-treatment of parylene-N films were investigated to develop a highly sensitive SPR biosensor. The effects of the plasma power and plasma-treatment time on the surface of parylene-N films were analyzed by measuring film contact angle and roughness from atomic force microscopy images. The plasma power was applied at a range of 0–100W for different treatment times. The influence of plasma-treatment was also analyzed using the depth profiles from X-ray photospectroscopy. From this analysis, chemical functional groups (those related to oxygen) were introduced and were estimated to penetrate up to 4nm and 8nm from the top surface of the parylene-N film due to treatment with plasma powers of 50W and 100W, respectively, for 1min. Based on the optimum plasma-treatment conditions for the plasma power and the plasma-treatment time, an SPR biosensor was developed for the detection of the human C-reactive protein.

Highly transparent superhydrophobic thin film with low refractive index prepared by one-step coating of modified silica nanoparticles

An easy and effective method to prepare superhydrophobic thin film has been developed. The film with optically transparent and low refractive index was composed by one-step coating with modified silica nanoparticles. The silica nanoparticles were prepared by sol–gel process of hydrolysis and condensation of alkoxysilane compounds and then surface modification silica nanoparticles, 50 ± 10 nm, were accomplished using methoxytrimethylsilane (MOTMS). Water contact angle of film increased with the weight of MOTMS of silica sol. When the weight of MOTMS was optimized, the water contact angle and sliding angle of film were 152.8° and less than 10°, respectively. The transmittance of film was also increased as compared to the un-coated microscope glass slide, from 91 to 93.5 %. The refractive index of the film was approximately 1.09 as measured by ellipsometer. The superhydrphobic thin film was also successfully made by using spray coating and the water contact angle of this film was more than 160°. Surface morphology of difference coating methods, dip and spray, were studied. Our result suggests that the film can be applied for superhydrophobicity and optical applications.

천연 고분자가 함유된 락타이드 글리콜라이드 공중합체 필름에서 슈반세포의 부착과 증식 거동 비교평가

본 연구에서는 신경세포인 슈반세포(SC)의 증식에 가장 적합한 생체재료를 연구하였다. 락타이드 글리콜라이드 공중합체(PLGA)에 탈미네랄 골분(demineralized bone particle, DBP), 소장점막하조직(small intestine submucosa, SIS), 그리고 실크를 각각 20% 첨가하여, 용매 증발법으로 각각의 필름을 제조하고, SC세포의 부착과 증식을 확인하기 위해 MTT, SEM 그리고 RT-PCR 분석을 실시하였다. 또한 필름의 친수성을 확인하기 위해 접촉각을 측정하였다. 분석 결과, PLGA/DBP 20% 필름에서 높은 친수성을 보였으며, SC의 부착과 증식률이 다른 군에 비해 크게 증가한 것을 확인할 수 있었다. 따라서 PLGA/DBP 필름은 중추신경재생 재료로 활용할 수 있을 것으로 사료된다. This study was designed to find an appropriate biomaterial to proliferate Schwann cell (SC). Poly(lactic-co-glycolic acid) (PLGA) films mixed with demineralized bone particle (DBP), small intestine submucosa (SIS), and silk were fabricated by a solvent casting method. Analysis of MTT, SEM and RT-PCR were performed to confirm adhesion and proliferation of SC. Contact angle of films was assayed for hydrophilicity of films. We confirmed that PLGA/DBP 20% film showed higher hydrophilicity, promoted adhesion and proliferation of SC than other films. It was concluded that PLGA/DBP film can be applied for the scaffold biomaterials for the regeneration of central nerve system.

이온빔 조사에 의한 기능성 고분자 필름의 표면 특성

Polycarbonate (PC) films have been irradiated with various kinds of ions according to energy and dose. Change of the optical transmittance and chemical characteristics were confirmed by UV-VIS and FTIR (ATR) spectroscopy respectively. These UV-A block in 400 nm was variable from 10 to 100% according to energy and doses. Surface electrical resistance of PC film irradiated by ion beam was , which reveal variation of conduction. Contact angle of film irradiated by ion beam was decreased than the pristine film. Polymer surface morphology was examined by means of atomic force microscopy (AFM). As expected, degradation of polymer film was higher after irradiation with heavier Xe ions but the roughness in the polymer surface morphology were more pronounced for Ar ions. This observed effect can be explained by stronger compaction of polymer surface layer in the case of Xe irradiation, connected with a reduction of free volume available.

Using a monocular optical microscope to assemble a wetting contact angle analyser

The ability of a solid surface to be wetted by a liquid can be classified by its wetting contact angle, θC: hydrophilic (θC<90°), hydrophobic (90°⩽θC⩽150°), or super-hydrophobic (θC>150°). To study the wetting behaviour of material surfaces, commercial contact angle analysers are generally employed. In this paper, we report on the construction and testing of a wetting contact angle analyser. To test the performance of the measurement system, we have measured the contact angles of films from commercial paraffin wax and polytetrafluoroethylene (PTFE). The contact angles are found to be in good agreement with the values described in the literature; thus, our analyser can be useful not only for research but also for educational purposes.

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.

NaOH처리시 Poly(ethylene terephthalate)필름의 표면특성에 영향을 주는 Diamine의 첨가효과

This study is a preliminary investigation of the influence of surface characteristics of substrates on detergency of particulate soil. The surface of PET film was modified with NaOH and NaOH+ethylene diamine on different times. The surface morphology of the film was scanned by AFM and surface energies were calculated from measured contact angles between several solutions and film based on the geometric mean and a Lewis acid base method. The surface morphology of PET film treated with NaOH and NaOH+ethylene diamine became more etched, and the surface area, surface roughness and the coefficient of friction of film increased with treatment of NaOH and NaOH+ethylene diamine. The contact angle of film treated with NaOH and NaOH+ethylene diamine decreased in water and surfactant solution; in addition, the surface energy increased was largely attributed to the increased portion on the polar surface energy of film. However, the effect of the diamine addition to the NaOH treatment solution on surface characteristics of PET film was insignificant.

Polynorbornene/fluorosilica hybrids for hydrophobic and oleophobic coatings

Polynorbornene dicarboxylic anhydride (PNA)/fluorosilica hybrid coating materials with good hydrophobicity, oleophobicity, transparency, thermal stability, and hardness were synthesised using a sol–gel method. The surface structure, transparency, hydrophobicity, oleophobicity, and surface free energy of the coating could be controlled by adjusting the fluorosilane ratio. The maximum static water and oil contact angles of films were 112° and 87°, respectively. The PNA/fluorosilica hybrid films exhibited good transparency and colourlessness. The marks written using water and oil-based pens on the films could be erased with a tissue even after eight times. In addition, the hardness of the hybrid films was enhanced to 4H with increasing fluorosilane content.

O2플라즈마로 전처리된 PET 및 PI 필름의 2단계 CHF3플라즈마 처리가 필름의 표면특성에 미치는 영향

Poly(ethylene terephthalate) and poly(imide) surfaces pre-treated by <TEX>$O_2$</TEX> plasma were modified by two-step <TEX>$CHF_3$</TEX> plasma, and the plasma modified film surface were investigated with scanning probe microscopy, X-ray photoelectron spectroscopy, and contact-angle and surface energy to characterize the surfaces. The surface energies were calculated from measured contact angles between several solutions and film-based on geometric means and the Lewis acid-base method. The exposure of the PET and PI film surfaces pre-treated by <TEX>$O_2$</TEX> plasma to the two-step <TEX>$CHF_3$</TEX> plasma led to the decrease in surface roughness and increase of the contact angles of film in water and surfactant solution. Primarily because of the contribution of polar force, the surface energy and hydrophilicity of PET and PI film treated by <TEX>$CHF_3$</TEX> plasma decreased greatly. Electron spectroscopy for chemical analysis (ESCA) indicated that the <TEX>$CHF_3$</TEX> plasma treatment introduced fluorine functional groups led to a decrease of the surface energy and hydrophilicity of PET and PI film.

자기세정산업용 소재 개발을 위한 O2플라즈마 처리가 Poly(imide) 필름의 표면 형태 및 특성에 미치는 영향

Abstract This study was a preliminary study to investigate the influence of surface morphology and characteristicson the self-cleaning of substrates. PI film was treated by O 2 plasma to modify the surface; in addition, AFMand Fe-SEM were employed to examine the morphological changes induced on a PI film treated by O 2 plasma and surface energies calculated from measured contact angles between several solutions and PIfilm based on the geometric mean and a Lewis acid base method. The surface roughness of PI film treatedby O 2 plasma increased with the duration of the O 2 plasma on PI film due to the increased surface etching.The contact angle of film treated by O 2 plasma decreased with the increased treatment time in water andsurfactant solution; in addition, the surface energy increased with the increased treatment times largely attri-buted to the increased portion on the polar surface energy of PI film. The coefficient of the correlationbetween surface roughness and surface polarity such as contact angle and surface energy was below 0.35;however, it was over 0.99 for the contact angle and surface energy.Key words: PI film, O

Characterization of a multilayer film activated with Lactobacillus curvatus CRL705 bacteriocins

Bacteriocins produced by lactic acid bacteria offer enormous promise for food safety preservation. In this study an active multilayer film obtained by the incorporation of lactocin 705 and lactocin AL705, two bacteriocins produced by Lactobacillus curvatus CRL705 with antimicrobial activity against Lactobacillus plantarum CRL691 and Listeria innocua 7, respectively, was characterized for its potential application in active packaging technology. Film activity performance at different storage conditions, bacteriocins transfer into water and sunflower oil, and film surface properties were evaluated. Film activity against L. innocua 7 was maintained during 2, 4 and 6 weeks at 30, 10 and 5 °C respectively. At 30 and 10 °C, activity loss against L. plantarum CRL691 was observed on the second week of storage and after the fourth week at 5 °C. Results showed no significant difference for active multilayer film contact angle and seal properties compared to the control (without bacteriocins). A decrease in lactocin 705 inhibitory activity after sunflower oil contact was observed, while lactocin AL705 remained unaffected. After water contact, film activity was retained for both bacteriocins. As demonstrated by antimicrobial activity and physico-mechanical properties retention, lactocin 705 and AL705 active multilayer film present potential for application in active packaging technology.

Waterborne polyurethane/acrylate: Comparison of hybrid and blend systems

Polyurethane/acrylate hybrid composites in a broad range of composition (10, 30, 50, 70 and 90 wt.% of acrylic content), were obtained by emulsion polymerization of acrylic monomers (methyl methacrylate/ n-butyl acrylate/acrylic acid mixture) in the presence of preformed polyurethane chains with polymerizable terminal vinyl groups. Blends with the same acrylic content were also prepared by mixing polyurethane and acrylic dispersions. Samples were characterized by SEC, DLS, FTIR, UV, TEM, AFM, SAXS/WAXS and gel fraction content. Mechanical properties, Buccholz and pencil hardness, surface roughness and water contact angle of films were also determined. The effect of the acrylic content on morphology and film properties was also evaluated. Hybrids are crosslinked systems showing changes in the particle and film morphologies with increasing acrylic content. The properties of hybrid films show a non-linear behavior with the increase of the acrylic component, while physical blends exhibit a gradual behavior from PU to AC. FTIR results indicate better acrylic–polyurethane compatibility in hybrid systems than in physical blends. Hybrid composites with up to 70 wt.% of acrylic component are homogeneous by SAXS. On the other hand, AFM results show that blends are phase segregated systems at all composition levels.

Poly(ethylene Terephthalate) 필름의 표면모폴로지와 표면특성

This study was a preliminary investigation of the influence of surface characteristics of substrates on the detergency of particulate soil. A PET film was surface modified with NaOH and DMF for different times. The surface morphology of the film was scanned by AFM and the surface energies were calculated from the measured contact angles between several solutions and film based on a geometric mean and the Lewis acid base method. The surface morphology of the PET film treated with NaOH and DMF became more etched and swelled with an increased treatment time, respectively. The surface roughness and surface area of film treated with NaOH enlarged with increased treatment time. However, the coefficient of friction of film treated with NaOH and coefficient of friction, surface roughness, and surface area of film treated with DMF increased and then decreased with increased treatment time. The contact angle of film treated with DMF decreased with increased treatment time in water and surfactant solution; however, the effect of treatment time on the contact angle was different in both solutions for film treated with NaOH. By the treatment of PET film with NaOH and DMF, the polar group of the surface energy increased and the nonpolar group decreased; however, the change of total surface energy was not significant.

Study on the double fluorinated modification of the acrylate latex

Double fluorinated acrylate latex (DFAL) has been successfully prepared by macromolecule reaction between m-trifluoromethylphenylamine (m-TFMPA) and the single fluorinated acrylate latex (SFAL), which is prepared by semi-continuous seeded emulsion polymerization of butyl acrylate (BA), methyl methacrylate (MMA) 2-(perfluoro-(1,1-bis-isopropyl)-2-propenyl)oxyethyl methacrylate (POMA) and glycidyl methacrylate (GMA). The resultant DFAL is characterized by Fourier transform infrared (FTIR) spectrometry, contact angle determinator, dynamic light scattering detector and thermo-gravimetric analysis (TGA). Results show that the contact angle of DFAL film is improved in comparison with that of SFAL film. The surface properties especially the contact angle of the film with annealing have been improved greatly because more fluorine atom is introduced into the molecule of acrylate latex and moves to the surface of the film. However, the thermal stability of the DFAL film is not improved.

A study on the performance of hyaluronic acid immobilized chitosan film

In order to improve hydrophilicity and biocompatibility of chitosan, hyaluronic acid was immobilized onto the surface of chitosan film. The structure of films was characterized by Fourier transformed infrared spectroscopy with attenuated total reflectance (ATR-FTIR), x-ray photoelectron spectroscopy (XPS) and zeta potential. Results confirmed that hyaluronic acid was successfully immobilized on chitosan film. Transparency, water absorption percentage and contact angle of films were characterized. Results showed that there was no significant variation in transparency (p < 0.05) before and after immobilization, the maximum was up to 99% which was enough for corneal regeneration in clinical applications. After the immobilization, the time-dependent contact angle declined sharply (from 91.8° to 67.7° at 100 s). The hydrophilicity was significantly improved. The methylthiazol tetrazolium (MTT) (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay was used to assess cell viability and proliferation. Results showed that human cornea epithelial cells (HCEC) grew better on hyaluronic acid immobilized chitosan films than on chitosan films. The hyaluronic acid immobilized chitosan film could be a promising candidate material for corneal regeneration.

Structure and washing fastness of composite fluorocarbon/ZnO films prepared by RF sputtering

Composite fluorocarbon/ZnO films were deposited by RF sputtering, using polytetrafluoroethylene and Zn targets, on polyethylene terephthalate substrates. Argon and oxygen were used as working and reacting gases, respectively, with an oxygen:argon volume ratio of 3:1. The films were characterized by X-ray Photoelectron Spectroscopy, Fourier Transform Infrared Spectroscopy and static contact angle measurements. It was found that the deposited films are made up of the four components –CF 3, –CF 2–, –CF– and –C–. The proportions of the four components varied with sputtering conditions. There was a large number of C=C double bonds on the surface of deposited films. The static contact angle of the deposited films was greater than 90°, indicating excellent hydrophobicity. The contact angle of films decreased after washing, and the washing fastness of the composite films were slightly inferior to those of the fluorocarbon films.

Protein Immobilization on Epoxy-Activated Thin Polymer Films: Effect of Surface Wettability and Enzyme Loading

A series of epoxy-activated polymer films composed of poly(glycidyl methacrylate/butyl methacrylate/hydroxyethyl methacrylate) were prepared. Variation in comonomer composition allowed exploration of relationships between surface wettability and Candida antartica lipase B (CALB) binding to surfaces. By changing solvents and polymer concentrations, suitable conditions were developed for preparation by spin-coating of uniform thin films. Film roughness determined by AFM after incubation in PBS buffer for 2 days was less than 1 nm. The occurrence of single CALB molecules and CALB aggregates at surfaces was determined by AFM imaging and measurements of volume. Absolute numbers of protein monomers and multimers at surfaces were used to determine values of CALB specific activity. Increased film wettability, as the water contact angle of films increased from 420 to 550, resulted in a decreased total number of immobilized CALB molecules. With further increases in the water contact angle of films from 55 degrees to 63 degrees, there was an increased tendency of CALB molecules to form aggregates on surfaces. On all flat surfaces, two height populations, differing by more than 30%, were observed from height distribution curves. They are attributed to changes in protein conformation and/or orientation caused by protein-surface and protein-protein interactions. The fraction of molecules in these populations changed as a function of film water contact angle. The enzyme activity of immobilized films was determined by measuring CALB-catalyzed hydrolysis of p-nitrophenyl butyrate. Total enzyme specific activity decreased by decreasing film hydrophobicity.

Preparation and characterization of increased-efficiency photocatalytic TiO 2–2 xN x thin films

We report here on the characteristics of RF-sputtered 300 nm thick films of TiO 2–2 x N x prepared on glass substrates at 350 °C, by adjusting the N 2:Ar partial pressure ratio in the deposition chamber between 0.00 and 0.33. XRD, XPS, AFM and contact angle data were used to derive film structure, elemental composition and oxidation state of Ti, surface morphology and hydrophilicity, respectively. The band gap was derived from spectral data in the 350–450 nm range. Film structure and composition were changed by adjusting the partial pressure of the reactive gases during sputtering and by post-deposition annealing at 400 °C in air, for 90 min. The values of the contact angle of films' surface with de-ionized water and of surface free energy per unit area show that films are super-hydrophilic for high-nitrogen content. Correlations are made between film structure, elemental composition, electronic and wettability properties.