Use of self-assembled monolayers to improve the hydrophobic properties of PET film for photovoltaic applications

Schiavone, Nicola; Rossi, Gabriella; Incarnato, Loredana; Scarfato, Paola

doi:10.1063/1.5046037

Cited by 1 publication

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“…In this context, we are carrying out a study aimed to develop a simple route to change the wettability of PET-SiOx films for high barrier applications. In previous works, we developed a method to obtain flexible and transparent hydrophobic SAM nanocoating using different alkyl- and fluoroalkylsilanes as precursor molecules, by means of simple and effective single-step process carried out at room temperature and applied to a polyethylene terephthalate–silicon oxide substrate (PET-SiOx), with the demonstrated efficacy of SAM in improving the oxygen and water barrier characteristics of commercial PET-SiOx films, normally used in photovoltaics, without losing significant transparency and assessing high durability of the developed systems in aggressive environments [ 2 , 24 , 25 ]. In this work, using as precursor molecule the best among those already tested, i.e., 1H,1H,2H,2H-per-fluorodecyltrichlorosilane (FDTS), we intended to optimize the conditions of the deposition reaction to minimize the film wettability.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2019

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Inorganic–organic multilayer films consisting of polymers coated with thin inorganic oxidic layers (e.g., SiOx) ensure very high barrier performances against gas and vapor permeation, what makes them packaging materials suitable for sophisticated technical applications, including the encapsulation of photovoltaic devices or quantum dots, barrier films for optical displays, and transparent greenhouse screens. In these fields, surface coating or texturing of the multilayer protective films are effective technologies to improve their self-clean ability, thus reducing the required maintenance and ensuring longer durability and better performances. In this work, we used the self-assembled monolayer (SAM) technique to modify the surface and wetting properties of commercial polyethylene terephthalate-silicon oxide substrate (PET-SiOx) films developed for technical applications requiring a combined high barrier and transparency. The selected surface modifier was the 1H,1H,2H,2H-per-fluorodecyltrichlorosilane (FDTS). The reagent mixture composition was optimized for the lowest water and oil wettability, as well as the highest self-cleaning capacity and performance stability. In particular, for the used PET-SiOx film the best FDTS/film surface for both the lowest water and oil wettability was found to be equal to 26.5 mM/dm2, which changes the surface behavior from very hydrophilic (static water contact angle (CAw) = 21.5°) to hydrophobic (CAw = 101°), and gives a significant increment of the static oil contact angle (CAo) from 27° to 60°. Interestingly, the results demonstrated that the SAM reaction occurred also on the uncoated the PET side. After the SAM treatment, a small increase of the water vapor permeability is observed, probably due to a crack or defect onset of the SiOx coating of the SAM modified films. On this point, atomic force measurements demonstrated an increment of the SiOx coating layer roughness after the SAM treatment execution. Finally, the transparency changes of the SAM treated films, measured in the wavelength range 400–800 nm, were always small, so that the results were acceptable for the films’ use in applications where high transparency is required.

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Section: Introductionmentioning

confidence: 99%