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

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.

Proof-of-Concept of Detection of Counterfeit Medicine through Polymeric Materials Analysis of Plastics Packaging

“…Figure 2 shows typical ATR-FTIR spectra of blister packaging of samples of authentic A and counterfeit A1. The main bands identified in the ATR-FTIR spectra are as follows: 609 cm −1 and 679–681 cm −1 due to C–Cl bond stretching [ 27 ]; 964 cm −1 : rocking of CH 2 group; 1251–1252 cm −1 : C–H bending; 1328–1330 cm −1 and 1426 cm −1 : CH 2 bending. These results suggest the presence of PVC in the chemical composition of the forming polymer of the blister packaging.…”

Structural and Functional Properties of Fluorinated Silica Hybrid Barrier Layers on Flexible Polymeric Foil

“…The bands of medium intensity located in the range of 2980-2850 cm −1 were related to the symmetric and asymmetric stretching vibrations of C-H bonds in -CH 2 and -CH 3 groups. The bending vibrations of C−H bonds were also present at 1350-1490 cm −1 [39,40]. The absorption seen for (CF)6 and (CF)10 in the range of 1100-1250 cm −1 was the characteristic bands of the C-F stretching vibrations in -CF 2 and -CF 3 groups.…”

Effect of Modified Silica Materials on Polyvinyl Chloride (PVC) Substrates to Obtain Transparent and Hydrophobic Hybrid Coatings

“…The silica materials were prepared using the sol-gel method in a similar way to that previously reported [27]. In this work, tetraethoxysilane (TEOS) was used as a silica source, and silane precursors (ethoxydimethylvinylsilane (DMVES), triethoxyoctylsilane (OTES), and trimethoxyhexadecylsilane (HDTMES)) were used as modifying agents (see Table 1).…”

“…In our previous study [27], we showed that the transparent and antireflective coatings on polyvinyl chloride (PVC) substrates can be obtained through the sol-gel method under mild conditions, using methyltriethoxysilane (MTES) and vinyltrimethoxysilane (VTMES). The obtained results indicated a reduction of reflectance (10%) for the sol-gel silica coatings, at the wavelength of 550 nm, compared with uncoated PVC substrate.…”