An Easy Route to Wettability Changes of Polyethylene Terephthalate–Silicon Oxide Substrate Films for High Barrier Applications, Surface-Modified with a Self-Assembled Monolayer of Fluoroalkylsilanes (original) (raw)
Related papers
Surface and Coatings Technology, 2014
Hydrophobic layers are generated and chemisorbed onto standard coating materials for photovoltaic (PV) devices in order to improve their barrier properties against the atmospheric degradation agents and achieve a higher lifetime for the coated devices. The hydrophobic layers are deposited on PET-SiOx substrates using two different molecules (alkylsilanes and fluoroalkylsilanes) as precursors. High liquid barrier properties are achieved for the fluoroalkylsilane coated PET-SiOx, best results being average water contact angle N 130°and average oil contact angle N 90°. A chemical mechanism hypothesis is provided in order to explain the different reactive behavior observed for the PET-SiOx samples with alkylsilanes and fluoroalkylsilanes, respectively. Moreover, the oxygen barrier properties are significantly improved by the fluoroalkylsilane layer deposited in ethanol, that leads to a 70% reduction of the Oxygen Transmission Rate (OTR) compared to that of the uncoated PET-SiOx substrate.
Applied Nanoscience, 2016
A method was developed for generating transparent and hydrophobic nanolayers chemisorbed onto flexible substrates of ethylene tetrafluoroethylene-silicon oxide (ETFE-SiOx). In particular, the effect of the deposition time and of the precursor molecule on the nanocoating process was analyzed with the aim of pursuing an optimization of the above method in an industrial application perspective. It was found that precursor molecule of triethoxysilane allowed to obtain better hydrophobic properties on the SiOx surface in shorter times compared to trichlorosilane, reaching the 92 % of final contact angle (CA) value of 106°after only 1 h of deposition. The optical properties and surface morphology were also assessed in function of time, revealing that an initial transparency reduction is followed by a subsequent transmittance increase during the self assembly of fluoroalkylsilanes on the SiOx surface, coherently with the surface roughness analysis data. Encouraging results were also obtained in terms of oleophobic properties improvement of the nanocoated surfaces.
SiOx-Based Multilayer Barrier Coatings Produced by a Single PECVD Process
Plasma Processes and Polymers, 2009
Multilayer organic/inorganic gas barrier coatings on plastics are needed for high performance demanding applications from OLEDs to packaging. In order to simplify the multilayer deposition process, we developed a single step vacuum process where silicon oxide-based PECVD multilayers are obtained by the modulation of the hexamethyldisiloxane (HMDSO) precursor inlet and interfaces are controlled by pumping speed. In this way, depending on O2/HMDSO ratio, ‘ceramic’ or ‘polymeric’ layers are deposited, with nanometre control of thickness of layers and interfaces. Permeability behaviour of the multilayer structures obtained is described as a function of the number of layers and their thickness.
Thin Solid Films, 2005
A novel process for polyethylene terephthalate (PET) surface modification with a silica-like thin layer is proposed. 3-Aminopropyltrimethoxysilane was employed to react with acetone to form dimethyliminopropyltrimethoxysilane (DIPTMS) after aging for 10 days at room temperature. After hydrolysis of alkoxy groups in DIPTMS, dimethylimine-modified silica clusters occurred resulting in an increase of the solution viscosity. Consequently, a dense and homogeneous thin layer was easily dip-coated onto a PET film. After heat treatment at 150 8C, a smooth, flexible and transparent silica-like film (about 70 nm thick) was formed via dehydration and condensation. The surface of the PET dramatically changed from hydrophobic (water contact angle: 70F28) to hydrophilic (45F38). As an attempt for application, a dense film of lithium metasilicate (Li 2 Od 2SiO 2 d nH 2 O) was successfully prepared by dip coating on the modified PET film, which appeared very low oxygen permeability of about 0.17 cm 3 /m 2 day atm at 23 8C and 85% humidity.
SiOx Gas Barrier Coatings on Polymer Substrates: Morphology and Gas Transport Considerations
The Journal of Physical Chemistry B, 1999
Plasma-enhanced chemical vapor deposition (PECVD) of SiO x thin coatings on polymer surfaces yields tough hybrid materials with the gas barrier properties and transparency of glass. Combination of these properties makes these materials ideally suited for food packaging and biomedical device applications. In this study, we employ a Non-Parametric Response Surface Methods optimization to identify the Magnetron-PECVD conditions responsible for superlative SiO x barrier coatings on poly(ethylene terephthalate) (PET). Oxygen and water vapor permeances of optimized PET/SiO x composites produced by hexamethyldisiloxane and trimethylsilane have been measured as functions of temperature and are found to exhibit Arrhenius behavior. The thermal activation energy for water vapor permeation, unlike that for oxygen permeation, depends on barrier performance and increases by as much as 20 kJ/mol with an increase in barrier efficacy. Examination of these materials by phase-imaging atomic force microscopy and energy-filtered transmission electron microscopy reveals a correlation between SiO x morphology (including defects) and barrier performance. Morphological and permeation results are compared to identify some of the physical factors governing water vapor permeation through SiO x-modified polymers.
Wettability of polypropylene films coated with SiOx plasma deposited layers
Surface and Coatings Technology, 2006
Surface wettability of polypropylene (PP) films has been significantly improved by the deposition of thin SiO x layers, elaborated from a mixture of hexamethyldisiloxane (HMDSO) and oxygen in a microwave DECR (distributed electron cyclotron resonance) plasma reactor (2.45 GHz, 400 W). Contact angle measurements, Atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) were used to study, respectively, the change in surface free energy, surface topography and chemical composition due to the deposition of thin SiO x layers. Contact angle measurements revealed that the water contact angle value is reduced from about 99°for untreated PP surface to nearly 30°for coated PP film. The polar component of the surface energy is considerably increased from 0.5 to 35 mJ/m 2. For films deposited in the presence of VUV photons, AFM images showed the growth of irregular structure due to substrate etching effect and the deconvolution results of the Si 2p XPS peaks indicated that the proportion of the partly oxidized silicon environment was the major component. However, for films deposited without the presence of VUV radiation, typical SiO 2 agglomerates can clearly be seen on PP surface at a thickness of about 29 nm and the proportion of the silicon dioxide was the major component.
Journal of Coatings Technology and Research, 2018
In this paper, a multilayer barrier thin film, based on polyvinylidene difluoride (PVDF)-silicon dioxide (SiO 2), has been fabricated on a PET substrate through a novel method of joint fabrication techniques. The inorganic SiO 2 thin film was deposited using a rollto-roll atmospheric atomic layer deposition system (R2R-AALD), while the organic PVDF layer was deposited on the surface of SiO 2 through the electrohydrodynamic atomization (EHDA) technique. The multilayer barrier thin films exhibited very good surface morphology, chemical composition, and optical properties. The obtained values for arithmetic surface roughness and water contact angle of the as-developed multilayer barrier thin film were 3.88 nm and 125°, respectively. The total thickness of the multilayer barrier thin film was 520 nm with a high optical transmittance value (85-90%). The water vapor transmission rate (WVTR) of the barrier thin film was $ 0.9 9 10 À2 g m À2 day À1. This combination of dual fabrication techniques (R2R-AALD and EHDA) for the development of multilayer barrier thin films is promising for gas barrier applications.
Silicon oxide surface as a substrate of polymer thin films
2001
We have measured the thickness of the oxide layer of Si wafers as a function of annealing temperature following treatment with either a modified Shiraki method (hydrophilic) or HF etching (hydrophobic). The results show that in both cases there exists a well-defined oxide layer, approximately 20 Å thick, which forms within at least 20 min of the processing. The density of this layer is initially 35% of the usual silicon oxides. The density of this layer gradually increases, approaching that of the pure oxides as the substrates are annealed from room temperature to 180°C. These results were interpreted in terms of a complexed layer of water. These results are consistent with dynamic secondary ion mass spectrometry, which shows that the amount of oxygen at the Si interface decreases with increasing temperature. The activation energies, obtained 31.6 and 19.3 kJ/mol for the hydrophilic and hydrophobic surfaces, are consistent with the evaporation energy of water. The effect of the adsorbed water was also evident on the diffusion coefficient of PS from the Si interface. The diffusion coefficient (D*) was expressed as D*) D WLF(T) exp(-∆Es/kT) where DWLF is the usual WLF temperature dependence diffusion coefficient, and the additional activation energy measured was ∆Es ∼ 6.7 kJ/mol per contact. The energy corresponds to the interaction energy between styrene monomers and mostly the adsorbed water layer.
Journal of Nanoscience and Nanotechnology, 2020
Organic solar cell and OLED display devices are very sensitive to moisture, which leading to a fast degradation by the exposure to moisture and oxygen in the air. Therefore, in order to enhance the stability of the devices, a barrier film having WVTR (Water Vapor Transmission Rate) of 10−4 to 10−6 g/m2/day is required. In order to prepare the barrier film with excellent moisture blocking characteristics, perhydro polysilazane (PHPS) is used, which is developed to prepare an insulating film for semiconductors. Also a catalyst is added to lower the curing temperature to 100 °C or less. The result shows that the polysilazane is cured and converted to SiO2 under 100 °C in 30 min. WVTR of the polysilazane coated film is estimated to be 2.1×10−2 g/m2/day. In addition, when the inorganic layer such as SiO2 and Al2O3 is deposited on the planarization layer, the film shows excellent moisture blocking characteristics having WVTR to be 7.9×10−5 g/m2/day.