Synthesis of superhydrophobic polymer/tungsten (VI) oxide nanocomposite thin films

Abstract

A method is presented to enable the preparation of superhydrophobic polymer/tungsten (VI) oxide (WO3) nanocomposite coatings on glass substrates. WO3 nanoparticles were incorporated via the swell-encapsulation-shrink method into superhydrophobic silicone polymer films deposited on glass via aerosol-assisted chemical vapour deposition (AACVD) to produce the novel nanocomposite films. The technique overcomes the limitations of previous methods for nanoparticle incorporation to provide a synthetic route to previously unattainable materials. The nanocomposite films retain the properties of the superhydrophobic polymer while the presence of the nanoparticles is clearly evident. As such, the films have a range of potential applications including high surface area photocatalysis and self-cleaning photochromic or electrochromic coatings. The two-stage synthesis is shown to be flexible and suggests great scope for producing any number of future novel materials. The thin films were characterized using scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) analysis, X-ray photoelectron spectroscopy (XPS), infra-red (FTIR) spectroscopy, X-ray diffractometry (XRD) and water droplet contact angle measurements. KEYWORDS

Enhanced Gamma Radiation Shielding of Polyester Composites Reinforced With the Recycled Tungsten Oxide and Their Structural, Thermal Characteristics

“…The intensity of these peaks increased with tungsten oxide content up to WO30PEs, followed by a reduction at WO50PEs, which suggests possible agglomeration at higher filler loadings [42]. This trend aligns with prior studies, where excessive tungsten oxide content led to particle clustering, reducing effective interaction sites [43]. The peak at ~704 cm -1 associated with W O stretching [41] was most prominent in WO3E0PEs, reinforcing the observation that this composition achieved optimal dispersion.…”

“…Overall, FTIR analysis confirms the successful integration of tungsten oxide into the PE matrix with minimal disruption to the polymer backbone. The intensity variations and minor peak shifts suggest primarily physical interactions, aligning with previous studies on tungsten oxide-polymer composites [31,42,43]. The observed trends in peak intensities further correlate with the flexural properties, where WO30PEs exhibited the highest mechanical strength, indicating that optimal tungsten oxide dispersion plays a critical role in enhancing composite performance.…”

“…Upon incorporation of tungsten oxide, WO5PEs displayed the most pronounced overall Raman signals. A distinct and intense band emerged at 404 cm -1 , markedly stronger than in PEs, assignable to O W O bending vibrations [43]. Similarly, sharp signals at 619 and 650 cm -1 -most intense in WO5PEs-correspond to W O stretching and lattice vibrations in hydrated or monoclinic WO 3 phases [41,43].…”

“…A distinct and intense band emerged at 404 cm -1 , markedly stronger than in PEs, assignable to O W O bending vibrations [43]. Similarly, sharp signals at 619 and 650 cm -1 -most intense in WO5PEs-correspond to W O stretching and lattice vibrations in hydrated or monoclinic WO 3 phases [41,43]. All composites exhibited a band at ~272 cm -1 , characteristic of O W O bending [41,48], and new features at ~810 and 888 cm -1 .…”

Enhanced Gamma Radiation Shielding of Polyester Composites Reinforced With the Recycled Tungsten Oxide and Their Structural, Thermal Characteristics

“…The intensity of these peaks increased with tungsten oxide content up to WO30PEs, followed by a reduction at WO50PEs, which suggests possible agglomeration at higher filler loadings [42]. This trend aligns with prior studies, where excessive tungsten oxide content led to particle clustering, reducing effective interaction sites [43]. The peak at ~704 cm -1 associated with W O stretching [41] was most prominent in WO3E0PEs, reinforcing the observation that this composition achieved optimal dispersion.…”

“…Overall, FTIR analysis confirms the successful integration of tungsten oxide into the PE matrix with minimal disruption to the polymer backbone. The intensity variations and minor peak shifts suggest primarily physical interactions, aligning with previous studies on tungsten oxide-polymer composites [31,42,43]. The observed trends in peak intensities further correlate with the flexural properties, where WO30PEs exhibited the highest mechanical strength, indicating that optimal tungsten oxide dispersion plays a critical role in enhancing composite performance.…”

“…Upon incorporation of tungsten oxide, WO5PEs displayed the most pronounced overall Raman signals. A distinct and intense band emerged at 404 cm -1 , markedly stronger than in PEs, assignable to O W O bending vibrations [43]. Similarly, sharp signals at 619 and 650 cm -1 -most intense in WO5PEs-correspond to W O stretching and lattice vibrations in hydrated or monoclinic WO 3 phases [41,43].…”

“…A distinct and intense band emerged at 404 cm -1 , markedly stronger than in PEs, assignable to O W O bending vibrations [43]. Similarly, sharp signals at 619 and 650 cm -1 -most intense in WO5PEs-correspond to W O stretching and lattice vibrations in hydrated or monoclinic WO 3 phases [41,43]. All composites exhibited a band at ~272 cm -1 , characteristic of O W O bending [41,48], and new features at ~810 and 888 cm -1 .…”

Sonochemical Routes to Superhydrophobic Soft Matter Coatings: Comparing Silica and Copper Oxide Coatings on Polyester Fabric

“…For fibrous hydrophobic surfaces, water forms bead-like drops, minimizing the solid–liquid contact area, to reduce surface free energy, when the fabric surface tension (γ C ) is lower than the liquid surface tension (γ L ). , For textile substrates, γ C also depends on the material properties such as yarn composition, fabric structure (i.e., synthetic material vs natural, thread density, floats), and surface features (i.e., being composed of microfibers possessing inherent binary nano- and microscaled textures) that allow for hydrophobic and even superhydrophobic characteristics to be achieved (often in combination with modifying hydrophobic agents). , Thus, while rough surfaces are usually fragile due to the high local pressures under mechanical load, a hierarchical, dual-scale surface roughness can yield both coating durability and high hydrophobicity while any impinging water droplets are firmly pinned to the surface due to air trapped within the nanoscale structures. , Dendritic copper-based structures offer high surface areas due to this hierarchical roughness and higher amplitude of asperity that allows control of surface wettability . In addition to the material focus in this paper, alternative materials (e.g., PDMS, ZnO, TiO 2 , among many others) have been explored by other authors, due to similar hierarchical properties. − …”

Enhanced Gamma Radiation Shielding of Polyester Composites Reinforced With the Recycled Tungsten Oxide and Their Structural, Thermal Characteristics

“…The intensity of these peaks increased with tungsten oxide content up to WO30PEs, followed by a reduction at WO50PEs, which suggests possible agglomeration at higher filler loadings [42]. This trend aligns with prior studies, where excessive tungsten oxide content led to particle clustering, reducing effective interaction sites [43]. The peak at ~704 cm -1 associated with W O stretching [41] was most prominent in WO3E0PEs, reinforcing the observation that this composition achieved optimal dispersion.…”

“…Overall, FTIR analysis confirms the successful integration of tungsten oxide into the PE matrix with minimal disruption to the polymer backbone. The intensity variations and minor peak shifts suggest primarily physical interactions, aligning with previous studies on tungsten oxide-polymer composites [31,42,43]. The observed trends in peak intensities further correlate with the flexural properties, where WO30PEs exhibited the highest mechanical strength, indicating that optimal tungsten oxide dispersion plays a critical role in enhancing composite performance.…”

“…Upon incorporation of tungsten oxide, WO5PEs displayed the most pronounced overall Raman signals. A distinct and intense band emerged at 404 cm -1 , markedly stronger than in PEs, assignable to O W O bending vibrations [43]. Similarly, sharp signals at 619 and 650 cm -1 -most intense in WO5PEs-correspond to W O stretching and lattice vibrations in hydrated or monoclinic WO 3 phases [41,43].…”

“…A distinct and intense band emerged at 404 cm -1 , markedly stronger than in PEs, assignable to O W O bending vibrations [43]. Similarly, sharp signals at 619 and 650 cm -1 -most intense in WO5PEs-correspond to W O stretching and lattice vibrations in hydrated or monoclinic WO 3 phases [41,43]. All composites exhibited a band at ~272 cm -1 , characteristic of O W O bending [41,48], and new features at ~810 and 888 cm -1 .…”

Sonochemical Routes to Superhydrophobic Soft Matter Coatings: Comparing Silica and Copper Oxide Coatings on Polyester Fabric

“…For fibrous hydrophobic surfaces, water forms bead-like drops, minimizing the solid–liquid contact area, to reduce surface free energy, when the fabric surface tension (γ C ) is lower than the liquid surface tension (γ L ). , For textile substrates, γ C also depends on the material properties such as yarn composition, fabric structure (i.e., synthetic material vs natural, thread density, floats), and surface features (i.e., being composed of microfibers possessing inherent binary nano- and microscaled textures) that allow for hydrophobic and even superhydrophobic characteristics to be achieved (often in combination with modifying hydrophobic agents). , Thus, while rough surfaces are usually fragile due to the high local pressures under mechanical load, a hierarchical, dual-scale surface roughness can yield both coating durability and high hydrophobicity while any impinging water droplets are firmly pinned to the surface due to air trapped within the nanoscale structures. , Dendritic copper-based structures offer high surface areas due to this hierarchical roughness and higher amplitude of asperity that allows control of surface wettability . In addition to the material focus in this paper, alternative materials (e.g., PDMS, ZnO, TiO 2 , among many others) have been explored by other authors, due to similar hierarchical properties. − …”

Enhanced Gamma Radiation Shielding of Polyester Composites Reinforced With the Recycled Tungsten Oxide and Their Structural, Thermal Characteristics

“…The intensity of these peaks increased with tungsten oxide content up to WO30PEs, followed by a reduction at WO50PEs, which suggests possible agglomeration at higher filler loadings [42]. This trend aligns with prior studies, where excessive tungsten oxide content led to particle clustering, reducing effective interaction sites [43]. The peak at ~704 cm -1 associated with W O stretching [41] was most prominent in WO3E0PEs, reinforcing the observation that this composition achieved optimal dispersion.…”

“…Overall, FTIR analysis confirms the successful integration of tungsten oxide into the PE matrix with minimal disruption to the polymer backbone. The intensity variations and minor peak shifts suggest primarily physical interactions, aligning with previous studies on tungsten oxide-polymer composites [31,42,43]. The observed trends in peak intensities further correlate with the flexural properties, where WO30PEs exhibited the highest mechanical strength, indicating that optimal tungsten oxide dispersion plays a critical role in enhancing composite performance.…”

“…Upon incorporation of tungsten oxide, WO5PEs displayed the most pronounced overall Raman signals. A distinct and intense band emerged at 404 cm -1 , markedly stronger than in PEs, assignable to O W O bending vibrations [43]. Similarly, sharp signals at 619 and 650 cm -1 -most intense in WO5PEs-correspond to W O stretching and lattice vibrations in hydrated or monoclinic WO 3 phases [41,43].…”

“…A distinct and intense band emerged at 404 cm -1 , markedly stronger than in PEs, assignable to O W O bending vibrations [43]. Similarly, sharp signals at 619 and 650 cm -1 -most intense in WO5PEs-correspond to W O stretching and lattice vibrations in hydrated or monoclinic WO 3 phases [41,43]. All composites exhibited a band at ~272 cm -1 , characteristic of O W O bending [41,48], and new features at ~810 and 888 cm -1 .…”

Sonochemical Routes to Superhydrophobic Soft Matter Coatings: Comparing Silica and Copper Oxide Coatings on Polyester Fabric

“…For fibrous hydrophobic surfaces, water forms bead-like drops, minimizing the solid–liquid contact area, to reduce surface free energy, when the fabric surface tension (γ C ) is lower than the liquid surface tension (γ L ). , For textile substrates, γ C also depends on the material properties such as yarn composition, fabric structure (i.e., synthetic material vs natural, thread density, floats), and surface features (i.e., being composed of microfibers possessing inherent binary nano- and microscaled textures) that allow for hydrophobic and even superhydrophobic characteristics to be achieved (often in combination with modifying hydrophobic agents). , Thus, while rough surfaces are usually fragile due to the high local pressures under mechanical load, a hierarchical, dual-scale surface roughness can yield both coating durability and high hydrophobicity while any impinging water droplets are firmly pinned to the surface due to air trapped within the nanoscale structures. , Dendritic copper-based structures offer high surface areas due to this hierarchical roughness and higher amplitude of asperity that allows control of surface wettability . In addition to the material focus in this paper, alternative materials (e.g., PDMS, ZnO, TiO 2 , among many others) have been explored by other authors, due to similar hierarchical properties. − …”