Preparation and Characterization of Some Sol-Gel Modified Silica Coatings Deposited on Polyvinyl Chloride (PVC) Substrates

Violeta Purcar,Raluca Augusta Gabor,Simona Căprărescu,Cristian Andi Nicolae,Adriana Nicoleta Frone,Mihai Anastasescu,Florentina Monica Raduly,Valentin Rădițoiu,Hermine Stroescu,Alina Rădițoiu,Raluca Manea,Georgiana Cornelia Ispas

doi:10.3390/coatings11010011

Abstract

Transparent and antireflective coatings were prepared by deposition of modified silica materials onto polyvinyl chloride (PVC) substrates. These materials were obtained by the sol-gel route in acidic medium, at room temperature (25 °C), using different alkoxysilanes with various functional groups (methyl, vinyl, octyl or hexadecyl). Physicochemical and microstructural properties of resulted silica materials and of thin coatings were investigated through Fourier Transforms Infrared Spectroscopy (FTIR), UV-Vis spectroscopy, Thermal Gravimetric Analysis (TGA), Dynamic Mechanical Analysis (DMA), Atomic Force Microscopy (AFM) and ellipsometric measurements. Wetting behaviors of the silica coatings were evaluated by measurement of static contact angle against water. FTIR spectra of materials confirmed the high degree of cross-linking that result from the formation of the inorganic backbone through the hydrolysis and polycondensation reactions together with the formation of the organic network. These sol-gel silica coatings showed a reduction in the reflectance (10%) compared with uncoated PVC substrate. AFM reveals that the films are uniform, and adherent to the substrate, but their morphology is strongly influenced by the chemical composition of the coating matrices. These silica coatings can be useful for potential electronic and optical devices.

Highlights

Many useful synthetic and/or processing strategies have been developed to prepare transparent hydrophobic and super-hydrophobic coatings
The results revealed that functional silica nanoparticles coating exhibited both superhydrophobic and oleophobic wetting properties, at lower temperatures (100 ◦C)
Transparent thin films with hydrophobic and antireflective properties were prepared by coating the plastic substrate (PVC) with silica materials obtained by the acid-catalyzed sol-gel process

Summary

Introduction

Many useful synthetic and/or processing strategies have been developed to prepare transparent hydrophobic and super-hydrophobic coatings. Chen et al [10] fabricated the multifunctional coating with superhydrophilic, high transparency, antireflective and self-cleaning properties via a chemical vapor deposition method. They demonstrated that the antifogging and transparency properties were due to the low water contact angles and the decrease of refractive index, respectively. Tasleem et al [14] synthesized transparent hybrid silica hydrophobic coatings using the chemical surfactant trimethoxyoctylsilane and green surfactants (Nelumbo nucifera) They showed that the hybrid silica coatings displayed good transparency, low surface energy and superhydrophobic property Eshaghi immobilized the nano-hybrid coatings on polycarbonate (PC) substrates through the sol-gel method, using silica nanoparticles, 3-glycidoxypropyltrimethoxysilane (GPTMS) and perfluorooctyltrichlorosilane (PFTS) [15]. Sutar et al [23] reported the preparation of superhydrophobic coating by applying the multiple layers of PVC/SiO2 NPs on glass substrate

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Conclusion